Microsoft Word - Drain Commissioner Rules Revised 4-1-23

RULES

OF THE

ST. CLAIR COUNTY

DRAIN COMMISSIONER

Procedures and Design Criteria

For Stormwater Drainage in Development Plans

Established Pursuant to:

The Land Division Act

Public Act No. 288 of 1967, as amended;

M.C.L. §§ 560.101 – 560.293

the Mobile Home Commission Act

Public Act No. 96 of 1987, as amended;

M.C.L. §§ 125.2301 – 125.2350

The Condominium Act

Public Act No. 59 of 1978, as amended;

M.C.L. §§ 559.101 – 559.276

The Michigan Drain Code

Public Act No. 40 of 1956, as amended

M.C.L. §§ 280.1 – 280.630

April 1, 2023

Robert Wiley

St. Clair County Drain Commissioner

Order of Adoption of Amendments

To the Rules of the St. Clair County Drain Commissioner

Whereas, the Land Division Act (Act 288 of 1967, as amended), M.C.L. §§ 560.101 – 560.293,

and the Mobile Home Commission Act (Act 96 of 1987), M.C.L. §§ 125.2301 –

125.2350, provide for the adoption and publication of rules and standards by the

County Drain Commissioner to govern outlet drainage and storm water facilities in

developments; and

Whereas, the Michigan Drain Code (Act 40 of 1956, as amended), M.C.L. §§ 280.1 – 280.630,

provides the general authority of Drain Commissioners and for other standards and

permitting requirements; and

Whereas, the Rules of the St. Clair County Drain Commissioner were originally adopted and

published by Drain Commissioner Thomas Donohue effective January 1, 1995, and

amended July 14, 2000, October 1, 2004, October 1, 2013, and October 1, 2018,

effective upon re-publication; and

Whereas, it has become necessary to further amend and to clarify certain of those rules;

Now, Therefore, It Is Hereby Ordered, that the Rules of the St. Clair County Drain

Commissioner are amended to read as follows and such amended rules shall take

effect immediately upon publication on the St. Clair County website, April 1, 2023.

TABLE OF CONTENTS

1.0 INTRODUCTION

1.1 Impacts of Development on Water Quantity

1.1.1 Examples of Changes in Watershed Hydrology and Stream Morphology

1.2 Impacts of Development on Water Quality

1.3 Framework for the Design of Storm water Management Systems

1.3.1 Source Controls

1.3.2 Site Controls

1.3.3 “Drain” and “Drainage District” Defined

1.4 Purpose of These Rules

2.0 DEVELOPMENTS REQUIRING REVIEW and SUBMISSION REQUIREMENTS

Condition I

Condition II

Condition III

2.1 Platted Subdivisions

2.1.1 Pre-Preliminary Plats

2.1.2 Preliminary Plats

2.1.3 Construction Plans

2.1.4 Final Plats

2.2 Condominium Developments

2.2.1 Preliminary Plans

2.2.2 Construction Plans

2.3 Private Road or Land Split Developments

2.3.1 Preliminary Plans

2.3.2 Construction Plans

2.4 Manufactured Housing Communities / Mobile Home Parks

2.4.1 Preliminary Plans

2.4.2 Construction Plans

2.5 Commercial or Industrial Developments

2.5.1 Preliminary Plans

2.5.2 Construction Plans

2.6 Direct or Indirect Discharges to an Established Drain

2.7 Drain Crossings, Culverts, Tiling, and/or Enclosing an Established Drain

2.8 Drain Widening, Deepening, or Relocation

2.9 Adding or Subtracting Land to/from a Drainage District and/or Construction of a

Drain for Ascription as an Established Drain

3.0 PLAT/PLAN REQUIREMENTS and PROCEDURES

3.1 Preliminary Plat/Plan Requirements & Procedures

3.2 Construction Plan Requirements & Procedures

3.3 Final Plat Requirements & Procedures

3.3.1 Procedure for the Construction of Drainage Systems Prior to Final Plat

Approval

3.3.2 Procedure for Drainage Systems Constructed Subsequent to Final Plat

Approval

3.4 Other Permits & Requirements

3.4.1 Soil Erosion & Sedimentation Control Permit

3.4.2 NPDES Permit-by-Rule

3.4.3 Other Requirements

3.5 Procedures for Appeal of Decision of Drain Commissioner

4.0 DESIGN STANDARDS for STORMWATER SYSTEMS

4.1 General Requirements

4.2 Established Drains

4.3 Storm Sewers

4.4 Open Channels

4.5 Culverts

4.6 Bioretention

4.6.1 Pre-Design Site Evaluation

4.6.2 Design Criteria

4.7 Infiltration

4.7.1 Pre-Design Site Evaluation

4.7.2 Design Criteria

4.8 Detention Storage Facilities

4.8.1 Detention Basins

4.8.2 Underground Storage

4.9 Retention Basins

4.10 Wetlands and Low Lying Areas

4.11 Oil Separators

4.12 First Flush Basins and Sediment Collection Units

4.13 Design Reference Material

APPENDIX A Application for Drain Commissioner Review

APPENDIX B Review & Permit Fees

APPENDIX C Drainage Application and Permit Form

APPENDIX D Section 433 Agreement Application: Application to Add/Subtract Land to/from

a Drainage District

APPENDIX E Example Permit Status Table

APPENDIX F Preliminary Plat/Plan Checklist

APPENDIX G Construction Plan Checklist

APPENDIX H Model Forms of Stormwater System Maintenance Agreements

APPENDIX I Example Stormwater Handling Strategies

APPENDIX J Reference Tables

APPENDIX K Example Bioretention Details

APPENDIX L Example Infiltration Details

APPENDIX M Example Detention Basin Details

APPENDIX N Example Calculations

APPENDIX O Example Oil Removal BMP’s (Best Management Practices)

APPENDIX P Glossary

1.0 INTRODUCTION

These Rules of the St. Clair County Drain Commissioner are adopted pursuant to the general

authority granted under the Michigan Drain Code of 1956, Public Act No. 40 of 1956, as

amended, M.C.L. §§ 280.1 – 280.630 (hereinafter “Drain Code”) and other applicable laws, to

protect the public health, safety, and welfare in regarding drainage matters over which the Drain

Commissioner has jurisdiction. These Rules are meant to assist in maintaining the County’s

stormwater drainage systems, waterways and watersheds, focusing on the legally established

drainage districts and drains within St. Clair County. Specifically, these Rules are designed to

provide guidance in order for project design to minimize flood damage; to preserve farm

drainage; to promote best management practices relating to drainage; to protect the quality of

surface and ground waters; to protect St. Clair County residents’ natural flow rights under

common law; and to manage the County’s drains, drainage resources, and drainage districts for

multiple purposes including drainage, sustainable development, recreation, scenic beauty, and

fish and wildlife habitats. These Rules are applicable to all developments subject to review and

approval of the Drain Commissioner and over which the Drain Commissioner has jurisdiction.

These Rules provide minimum standards for developments covered under the Rules, provided,

however, that the Drain Commissioner reserves the right to deviate from the specific design

standards set forth in the Rules when, on a case-by-case basis, such deviation is appropriate or

necessary in order to accommodate the goals and purposes underlying these Rules. These rules

and their implementation are designed to promote low impact designs such as rain gardens or

other site control of stormwater. The Drain Commissioner is committed to working with those

developing projects or applying for permits to use alternate drainage methods which help meet

local landscape ordinance requirements and improve the quality of water in our environment.

The following discussion outlines basic ideas and principals of stormwater management, and

provides a conceptual foundation for the design standards contained in this document.

1.1 Impacts of Development on Water Quantity

The hydrology of a watershed changes in response to site clearing and development of the

natural landscape. A site’s existing stormwater storage capacity can be lost as vegetation is

removed, natural depressions are graded and both topsoil and wetlands are eliminated. As the

soil is compacted and resurfaced with impervious materials, rainfall may no longer penetrate into

the ground and runs off of the land. These modifications, along with the installation of drainage

facilities, alter natural drainage patterns within the area drained.

1.1.1 Examples of Changes in Watershed Hydrology and Stream Morphology

 Increases in volume of runoff raise the flood stage and the frequency of severe flood

events.

 Bankfull floods fill the stream channel to the top of its banks, but do not spill over into

the floodplain. Increased bankfull flooding subjects the stream channel to continual

disturbance and scour.

 Increases in flow velocities are caused by the combined effect of greater discharges,

shorter times of concentration, and smoother hydraulic surfaces.

 Stream flow fluctuations increase dramatically as runoff is concentrated into more

quickly rising, higher peaks with equally abrupt returns to pre-storm level discharges.

Increased flow fluctuations may disrupt habitats and reduce the diversity of aquatic

species regardless of water quality.

 If infiltration into the underlying water table is reduced, there is often a lowering of the

level of surface waterbodies that are dependent on groundwater to maintain base flows

during dry periods.

 Channel widening and down-cutting contribute to increased runoff rates and flow

fluctuations.

 Streambank erosion accelerates as channels are disturbed by undercutting, tree-falls and

bank slumping.

 Sediment loads increase with streambank erosion and construction site runoff. These

sediments settle out and form shifting bars that often accelerate the erosion process by

deflecting runoff into sensitive bank areas.

 Increased sedimentation and channel widening affect aquatic habitats. Stream structure

changes as the gradient of the stream adjusts to accommodate frequent floods. Sediment

deposition damages invertebrate habitat as well as fish spawning areas.

1.2 Impacts of Development on Water Quality

As development occurs, changes in land use may contribute new or additional pollutants to

storm-water runoff. In addition, some accompanying impervious surfaces may provide efficient

delivery of these pollutants into receiving waterways. Leaves, litter, animal droppings, exposed

soil from construction sites, fertilizer and pesticides are all washed off of the land. Vehicles and

deteriorating urban surfaces deposit trace metals, oil, and grease onto streets and parking lots.

These and other toxic substances may be carried by stormwater and conveyed through creeks,

ditches and storm drains into our rivers and lakes.

In short, the ecology of drains and waterways may be re-shaped by the shifts in hydrology,

morphology and water quality that can accompany the development process. The stresses that

these changes place on the environment are often gradual and invisible, yet they may produce

significant effects over time: The Michigan Department of Environment, Great Lakes & Energy

(EGLE) has identified streams in the urban and urbanizing areas as requiring special initiatives to

restore degraded habitats, and to improve water quality.

To mitigate drainage impacts, it is necessary to evaluate the way that stormwater and land

development are managed. The following discussion provides a framework for this evaluation,

which encompasses the entire development process from land use planning and zoning to site

design and construction.

1.3 Framework for the Design of Stormwater Management Systems

Thoughtful site planning can substantially reduce environmental and drainage impacts associated

with development. Towards this end, communities, regulatory agencies, and designers must

evaluate the impact of each individual development project over the long term, and on a

watershed scale. Such an approach requires consideration of Best Management Practices

(BMPs) that function together as a system to ensure that the volume, rate, timing and pollutant

load of runoff remains stable and sustainable. A “BMP” is a practice or combination of practices

that prevent or reduce stormwater runoff and/or associated pollutants. This can be achieved

through a coordinated network of structural and nonstructural methods. In such a system, each

BMP by itself may not provide major benefits, but becomes very effective when combined with

others.

1.3.1 Source Controls

Source controls reduce the volume of runoff generated on-site, and eliminate initial opportunities

for pollutants to enter the drainage system. By working to prevent problems, source controls are

the best option for controlling stormwater, and include the following key practices:

 Preservation of existing natural features that perform stormwater management functions,

such as depressions, wetlands, and woodland and vegetative buffers along streambanks.

 The minimization of impervious surface area through site planning that makes efficient use

of paved, developed areas and maximizes open space. Encouraging flexible street and

parking standards and the use of permeable ground cover materials can also reduce

impervious surfaces.

 Direction of stormwater discharges to open grassed areas such as swales and lawns rather

than allowing stormwater to run off from impervious areas directly into the stormwater

conveyance system.

 Careful design and installation of erosion control mechanisms and rigorous maintenance

throughout the construction period. Effective erosion control measures include minimizing

the area and length of time that a site is cleared and graded, and the timely vegetative

stabilization of disturbed areas.

1.3.2 Site Controls

Site controls are the subject of this document. After the implementation of source controls, site

controls are then required to convey, pre-treat, and treat (e.g., detain, retain or infiltrate) the

stormwater runoff generated by development. The range of engineering and design techniques

available to achieve these objectives is to some degree dictated by site configuration, soil type,

and the receiving waterway. For example, flat or extremely steep topography may preclude the

use of grassed swales, which are otherwise preferable to curb and gutter systems. But while each

site will be unique, some universal guidelines for controlling stormwater quality and quantity can

be stated.

1.3.3 “Drain” and “Drainage District” Defined

The term “Drain” as used in these Rules shall have the meaning as proscribed in Section 3 of the

Drain Code as follows:

The word ‘drain’, whenever used in this act, shall include the main

stream or trunk and all tributaries or branches of any creek or river,

any watercourse or ditch, either open or closed, any covered drain,

any sanitary or any combined sanitary and storm sewer or storm

sewer or conduit composed of tile, brick, concrete, or other

material, any structures or mechanical devices, that will properly

purify the flow of such drains, any pumping equipment necessary

to assist or relieve the flow of such drains and any levee, dike,

barrier, or a combination of any or all of same constructed, or

proposed to be constructed, for the purpose of drainage or for the

purification of the flow of such drains, but shall not include any

dam and flowage rights used in connection therewith which is used

for the generation of power by a public utility subject to regulation

by the public service commission.

The term “Drainage District” as used in these Rules shall have the following meaning:

A Drainage District is any county or inter-county drainage district

legally established pursuant to applicable provisions of the Drain

Code. Drain Code Section 5 provides that each such drainage

district is a body corporate with the power to contract, to sue and

be sued, and to hold, manage, and dispose of real property, in

addition to any other powers conferred by law. Generally, a

drainage district is comprised of all lands which drain to a legally

established Drain.

1.4 Purpose of These Rules

It is the purpose of these site development rules to establish minimum stormwater management

requirements to meet the following objectives:

 Ensure that stormwater drainage systems and BMPs are adequate to address

stormwater management needs within a proposed development and protect the

drainage, property and water rights of landowners outside of the proposed

development.

 Reduce artificially induced flood damage.

 Minimize the degradation of existing watercourses.

 Prevent an increase in non-point source pollution.

 Maintain site hydrology to avoid detrimental changes in the balance between

stormwater runoff, groundwater recharge and evapo-transpiration.

Further documentation of the impacts of development on land and water resources and the

importance of stormwater management can be found in Chapter 2 of the Low Impact

Development Manual for Michigan (SEMCOG, 2008).

Low Impact Development Manual for Michigan, A Design Guide for Implementers & Reviewers

https://www.semcog.org/Reports/LID/files/assets/basic-html/page-1.html

2. 0 DEVELOPMENTS REQUIRING REVIEW and

SUBMISSION REQUIREMENTS

Pursuant to state law, all residential or industrial subdivisions and all manufactured housing

communities or mobile home parks must conform to these Rules and design standards adopted

by the Drain Commissioner. Additionally, these Rules and design standards will be applied to,

and a permit from the Drain Commissioner (see Appendix C) may be required for, all other

developments and construction activities that affect drainage conditions or drainage patterns for

which one or more of the following conditions

applies:

Condition I

The proposed development will directly impact a drain, for example, by directly contributing

flow or depositing sediment or contaminants into the drain.

Condition II

County or local ordinances or other legal authority require the Drain Commissioner's evaluation.

Additionally, the Drain Commissioner may apply these standards if requested by a local

municipality or county.

Condition III

The site development is in the defined Port Huron Urbanized Area and disturbs one or more

acres, including projects less than an acre that are part of a larger common plan of development

or sale, and discharges into a Municipal Separate Storm Sewer System (MS4) owned by or under

the jurisdiction of the SCCDO or a municipality which has adopted these Rules.

These conditions will also apply to projects of the SCCDO and St. Clair County as long as there

is no conflict with PA 40 of 1956 (Drain Code).

Outlined below are examples of types of developments and construction activities that may be

within the jurisdiction of the Drain Commissioner that are expressly addressed in the referenced

subsections of this Section of the Rule and which may generally require a Drainage Permit from

the Drain Commissioner:

2.1 Platted Subdivisions

2.2 Condominium Developments

2.3 Private Road or Land Split Developments

2.4 Manufactured Housing Communities / Mobile Home Parks

2.5 Commercial or Industrial Developments

2.6 Direct Discharges to an Established Drain

2.7 Drain Crossings, Culverts, Tiling and/or Enclosing an Established Drain

2.8 Drain Widening, Deepening or Relocation

Minor development or construction activities, such as those associated with a typical single-family residence, that

are not part of a larger common plan or development may be exempt from the Drainage Permit requirement.

2.9 Adding or Subtracting Land to/from a Drainage District and/or Construction of a Drain

for Ascription as an Established Drain.

The types of plans to be submitted are listed for each development type. Some of the legal

sources of the Drain Commissioner's authority are also cited. Details regarding the requirements

for plats and plans can be found in the following section, Section 3.0 Plat/Plan Requirements and

Procedures.

2.1 Platted Subdivisions

Pursuant to Land Division Act, PA 288 of 1967, as amended, M.C.L. §§ 560.101 – 560.293, and

the general authority of Drain Commissioners under the Drain Code

2.1.1 Pre-Preliminary Plats

Section 107 of the Land Division Act, M.C.L. § 560.107, states that a proprietor may submit a

pre-preliminary plat to a governing body for their information and review. The pre-preliminary

plat will be reviewed by the Drain Commissioner per the same standards as a preliminary plat.

Comments on the pre-preliminary plat will be provided for the proprietor’s consideration, but

approval from the Drain Commissioner is not required to proceed with submission of the

preliminary plat. For review of a pre-preliminary plat, the Drain Commissioner may charge the

same review fees that would be applicable to a preliminary plat.

2.1.2 Preliminary Plats

Section 105 of the Land Division Act, § 560.105, states that the approval of a preliminary plat

shall be conditioned upon compliance with any published rules of a county Drain Commissioner.

A checklist of requirements for preliminary plats can be found in Appendix F. Additional

requirements for preliminary plats can be found in Section 3.1 Preliminary Plat/Plan

Requirements & Procedures. Review fees for preliminary plat apply as outlined in Appendix B.

Approval of a preliminary plat does not constitute approval of construction or engineering plans

for the proposed subdivision. Construction and engineering plans must be approved prior to the

beginning of construction and prior to final approval.

2.1.3 Construction Plans

Construction plans will be reviewed for their compliance with the requirements described in

Section 3.2 and the design standards listed in Section 4.0 Design Standards for Stormwater

Systems. The plans must be approved by the Drain Commissioner prior to any on-site

construction or grading. Additionally, a Drainage Permit must be obtained from the Drain

Commissioner if one or more of the conditions in Section 2.0 apply. The initiation of grading or

building activities before plan approvals and/or permits from the Drain Commissioner is the

basis for issuance of a Stop Work Order. In addition, the completion of projects that do not

conform to approved plan specifications will not be tolerated by the Drain Commissioner and

may entail legal enforcement and/or withholding of approval of any final plats until outstanding

issues are resolved.

2.1.4 Final Plats

Section 192 of the Land Division Act, M.C.L. § 560.192, states that the Drain Commissioner

shall require that the proprietor provide for adequate stormwater facilities within the lands

proposed for platting and outlets thereto. If the stormwater facilities are not installed before

approval of the final plat, some form of surety must be posted with the Drain Commissioner.

Section 192 also allows the Drain Commissioner to require the proprietor to provide adequate

stormwater retention/detention systems and an arrangement for the future maintenance of the

stormwater facilities. All these requirements must be addressed before the final plat is submitted

for review. Additional details regarding the requirements for final plat approval can be found in

Section 3.3 Final Plat Requirements & Procedures. Section 146 of the Land Division Act,

M.C.L. § 560.146, states that a certificate shall be signed and dated by the Drain Commissioner

signifying that the provisions of Section 192 have been met and that the final plat meets the

Drain Commissioner's approval.

2.2 Condominium Developments

Pursuant to the Condominium Act, PA 59 of 1978, as amended, M.C.L. §§ 559.101 – 559.276,

and the general authority of Drain Commissioners under the Drain Code

Section 71 of the Condominium Act, M.C.L. § 559.171, requires that written notice be provided

to the Drain Commissioner prior to taking reservations under a preliminary reservation

agreement, recording a master deed for the property, or beginning construction for a

condominium project. The Drain Commissioner will review plans and offer comments/approval

as may be within his jurisdiction. Generally, the Drain Commissioner will review and approve

condominium plans using the same criteria that apply to subdivisions. Such review shall be

completed prior to the recording of the master deed for the condominium.

2.2.1 Preliminary Plans

Preliminary plans for condominium sites will be reviewed by the Drain Commissioner as per

preliminary plats. A checklist of requirements for preliminary plats/plans can be found in

Appendix F. Requirements for preliminary plans can be found in Section 3.1 Preliminary

Plat/Plan Requirements & Procedures. Approval of a preliminary plat does not constitute

approval of construction or engineering plans for proposed subdivisions, and construction and

engineering plans must be approved prior to the beginning of any construction and prior to the

final plat approval.

2.2.2 Construction Plans

Condominium construction plans must be reviewed by, and a Drainage Permit obtained from, the

Drain Commissioner if one or more of the Conditions in Section 2.0 apply. Construction plans

will be reviewed for their compliance with the requirements described in Section 3.2 and the

design standards listed in Section 4.0 Design Standards for Stormwater Systems. The plans must

be approved by the Drain Commissioner prior to any on-site construction or grading. Only upon

their approval will permits required from the Drain Commissioner be issued. The initiation of

grading or building activities before obtaining plan approvals and/or permits from the Drain

Commissioner is the basis for issuance of a Stop Work Order. Condominium master deeds shall

contain a legally binding plan for long-term maintenance of the stormwater facilities. Such plans

shall be reflective of/similar to subdivision stormwater management deed restrictions. Examples

of such stormwater facility maintenance agreements can be found in Appendix H. A copy of the

stormwater maintenance plan will be submitted to the Drain Commissioner as part of the review

process. All review fees and expenses will be paid before final approval is given to proceed with

construction activities.

2.3 Private Road or Land Split Developments

The Drain Commissioner may have jurisdiction over private road developments or land split

developments depending on how the property will be used and whether the use of the property

impacts a Drain. The jurisdictional criteria are set forth in Section 2.0 above. The Drain

Commissioner strongly recommends that plans for private road developments or land split

developments be submitted for review so as to avoid the risk that a project could be delayed

because approval was required but not obtained.

2.3.1 Preliminary Plans

If preliminary plans are submitted, preliminary plans for private road and land split

developments will be reviewed by the Drain Commissioner as per preliminary plats. A checklist

of requirements for preliminary plats/plans can be found in Appendix F. Requirements for

preliminary plans can be found in Section 3.1 Preliminary Plat/Plan Requirements & Procedures.

Preliminary plans will be approved by the Drain Commissioner contingent upon review of

detailed engineering and construction plans.

2.3.2 Construction Plans

Private road and land split development construction plans must be reviewed by, and a Drainage

Permit obtained from, the Drain Commissioner if one or more of the Conditions in Section 2.0

apply. Construction plans will be reviewed for their compliance with the requirements described

in Section 3.2 and the design standards listed in Section 4.0 Design Standards for Stormwater

Systems. The plans must be approved by the Drain Commissioner prior to any on-site

construction or grading. Only upon their approval will a permit be issued for discharge to an

established drain and/or for work in a drain right-of-way. The initiation of grading or building

activities before obtaining plan approvals and/or permits from the Drain Commissioner is the

basis for issuance of a Stop Work Order. Stormwater facility maintenance must be ensured

through a deed restriction or an equivalent legally binding agreement. Examples of such

stormwater facility maintenance agreements can be found in Appendix H. A copy of the

stormwater maintenance plan must be submitted to the Drain Commissioner as part of the review

process. All review fees and expenses must be paid before final approval is given to proceed

with construction activities.

2.4 Manufactured Housing Communities / Mobile Home Parks

Pursuant to the Mobile Home Commission Act, Act No. 96 of 1987, as amended, M.C.L. §§

125.2301 – 125.2350, and the general authority of Drain Commissioners under the Drain Code

Section 11 of the Mobile Home Commission Act, M.C.L. § 125.2311, states that a person who

desires to develop a mobile home park shall submit a preliminary plan to the county Drain

Commissioner for preliminary approval. It also states that the preliminary plan shall not include

detailed construction plans. Subsection 3 states that the Drain Commissioner shall review and

may approve the outlet drainage, and that the Drain Commissioner shall adopt and publish

standards to implement the subsection. These standards are as published in Section 4.0 Design

Standards for Stormwater Systems. Mobile home interior drainage may be reviewed to the

extent necessary to determine that the outlet drainage meets these standards, since inadequate

interior drainage may result in overflows to the receiving watercourse.

2.4.1 Preliminary Plans

Preliminary plans will include the location, layout, general design, and general description of the

mobile home park. A checklist of requirements for preliminary plans can be found in

Appendix F. Requirements for preliminary plats can be found in Section 3.1 Preliminary

Plat/Plan Requirements & Procedures. Preliminary plan approval will be contingent upon a

review of the engineering and construction plans and all details related to and affecting outlet

drainage

2.4.2 Construction Plans

Construction plans for mobile home parks must be reviewed by the Drain Commissioner to

determine that the adequacy of the outlet drainage has been considered. Additional aspects of

the plans for mobile home parks must also be reviewed by, and a Drainage Permit obtained from,

the Drain Commissioner if one or more of the Conditions in Section 2.0 apply. Construction

plans will be reviewed for their compliance with the requirements described in Section 3.2 and

the design standards listed in Section 4.0 Design Standards for Stormwater Systems. The plans

must be approved by the Drain Commissioner prior to any on-site construction or grading. Only

upon their approval will any permits from the Drain Commissioner be issued. The initiation of

grading or building activities before obtaining plan approvals and/or permits from the Drain

Commissioner may result in issuance of a Stop Work Order. Stormwater facility maintenance

must be ensured through a deed restriction or an equivalent legally binding agreement.

Examples of such stormwater facility maintenance agreements can be found in Appendix H. A

copy of the stormwater maintenance plan must be submitted to the Drain Commissioner as part

of the review process. All review fees and expenses must be paid before final approval is given

to proceed with construction activities.

Communication with the Drain Commissioner is strongly encouraged regarding all proposed

developments.

2.5 Commercial or Industrial Developments

Pursuant to the jurisdiction of the Drain Commissioner under the Drain Code as set forth in

Section 2 above and to the extent local ordinances require a permit.

Proposed commercial/industrial developments (e.g. shopping malls, apartments, schools, general

retail and wholesale establishments, factories, industrial complexes, etc.) or additions/

modifications to such existing developments must be reviewed by and a Drainage Permit

obtained from the Drain Commissioner if one or more of the Conditions in Section 2.0 apply or

if required by a local ordinance.

2.5.1 Preliminary Plans

If preliminary plans for proposed commercial/industrial construction activities are submitted,

they will be reviewed by the Drain Commissioner as per preliminary plats. A checklist of

requirements for preliminary plats/plans can be found in Appendix F. Requirements for

preliminary plans can be found in Section 3.1 Preliminary Plat/Plan Requirements & Procedures.

Submission of preliminary plans is encouraged, but not required. Approval of preliminary plans

by the Drain Commissioner is not required to proceed with submission of construction plans.

2.5.2 Construction Plans

Construction plans must be submitted to and a Drainage Permit obtained from the Drain

Commissioner if one or more of the Conditions in Section 2.0 apply. Construction plans will be

reviewed for their compliance with the requirements described in Section 3.2 and the design

standards listed in Section 4.0 Design Standards for Stormwater Systems. The plans must be

approved by the Drain Commissioner prior to any on-site construction or grading. Only upon

their approval will any permits from the Drain Commissioner be issued. The initiation of

grading or building activities before obtaining plan approvals and/or permits from the Drain

Commissioner is the basis for issuance of a Stop Work Order. A copy of the stormwater

maintenance plan will be submitted to the Drain Commissioner as part of the review process.

All review fees and expenses must be paid before final approval is given to proceed with

construction activities.

2.6 Direct or Indirect Discharge to an Established Drain

If point source or sheet flow drainage from any proposed development or any construction

activities are to be directed toward and/or empty into an established drain or to any watercourse

under the jurisdiction of the Drain Commissioner, compliance with these Rules and a Drainage

Permit and fees shall be required. This permit may be required in addition to approval of plats

and/or plans. Please refer to Appendix C for a Drainage Permit application: “Application and

Permit Authorizing Development or Construction Activities Affecting Drainage.” Unrestricted

discharge of stormwater from developments to an established drain or other watercourse within

the jurisdiction of the Drain Commissioner is unacceptable.

Before commencing to do any work on the site, the proprietor shall notify the Drain

Commissioner at least 48 hours in advance to provide for the inspection of the project by the

Drain Commissioner if required. The proprietor shall also notify the Drain Commissioner at the

completion of the project to provide for a final inspection by the Drain Commissioner if required.

Inspections by the Drain Commissioner shall not relieve the proprietor of his obligations. Only

upon the satisfactory completion of the project and final inspection will the Drain Commissioner

issue the Drainage Permit.

Pursuant to Section 423 of the Drain Code, no sewage or waste matter shall be discharged into an

established drain, which is capable of producing in the drain, detrimental deposits, objectionable

odor nuisance, injury to drainage conduits or structures, or capable of producing such pollution

of the waters of the state receiving the flow from the drains as to injure livestock, destroy fish

life, or be injurious to public health.

Pursuant to Section 423 of the Drain Code, non-storm water discharges to water courses under

the jurisdiction of the Drain Commissioner are prohibited. This may include illicit discharges,

direct dumping, disposal of materials, and/or illicit connections to water courses. The following

categories of non-storm water discharges are excluded from this prohibition unless they have

been identified as significant sources of pollutants to these water courses.

 Discharges or flows from firefighting activities

 Water line flushing and discharges from potable water sources

 Landscape irrigation runoff, lawn watering runoff, and irrigation waters

 Diverted stream flows and flows from riparian habitats and wetlands

 Rising groundwater and springs

 Uncontaminated groundwater infiltration and seepage

 Uncontaminated pumped groundwater, except for groundwater cleanups specifically

authorized by NPDES permits

 Foundation drains, water from crawl space pumps, footing drains, and basement sump

pumps

 Air conditioning condensation

 Waters from noncommercial car washing

 Street wash water

 Dechlorinated swimming pool water from single, two, or three family residences.

The SCC Drain Commissioner may inspect, investigate, and monitor suspected illicit discharges

into watercourses under his/her jurisdiction, and require and enforce the elimination of these

discharges. To the maximum extent practicable, illicit discharges shall be eliminated from water

courses under the SCC Drain Commissioner’s jurisdiction within 120 days of its presence being

confirmed by the SCC Drain Commissioner or his/her staff.

2.7 Drain Crossings, Culverts, Tiling and/or Enclosing an Established

Drain

A Drainage Permit from the Drain Commissioner is required for any and all culverts, bridges,

enclosures, and utility crossings of established drains. Section 425 of the Drain Code, M.C.L. §

280.425, states that a land owner may make a written request to the Drain Commissioner for

permission to tile or enclose an open drain at his/her own expense. The Drain Commissioner

may grant the request, via a Drainage Permit, but in so doing shall prescribe the size of the

enclosure to be used. In accordance with Section 421 of the Drain Code, M.C.L. § 280.421, a

permit shall not be issued to enclose a drain if the enclosure would obstruct the established drain.

2.8 Drain Widening, Deepening or Relocation

If the proprietor desires to perform construction activities within an existing drain right-of-way,

including, widening, deepening, or relocation of a drain, application for a Drainage Permit will

be filed with the office of the Drain Commissioner. This application will be accompanied by the

necessary release of right-of-way, in recordable form, accomplished by all owners of interest.

Preliminary and/or construction plans may be required for review as appropriate. Requirements

and procedures for preliminary plans and construction plans are described in Section 3.0.

2.9 Adding or Subtracting Land to/from a Drainage District, and/or

Construction of a Drain for Ascription as an Established Drain

If a proprietor desires to add or subtract land to/from a drainage district, and to construct a drain

for designation as an established drain, the Drain Commissioner’s approval must be obtained

prior to construction. Section 433 of the Drain Code, M.C.L. § 280.433, requires that the

proprietor enter into an agreement with the Drain Commissioner. The agreement would obligate

the proprietor to pay (or put on deposit) all costs associated with the new drain(s). The

agreement would require that a registered professional engineer prepare and certify all necessary

documents, including but not limited to:

 An updated map of the drainage district showing the district boundary

 A document indicating the total area (in acres) of the drainage district, the area of the

lands serviced by the new branches and/or extensions, and the total length (in miles and

fractions thereof) of all drains, branches, and/or new extensions within the district.

 A current listing of all parcels partially or totally within district boundary.

 Legal descriptions for each parcel partially or totally within district boundary.

 For each parcel partially within district, a general description of the portion of parcel

within district and the area (in acres) of that portion.

 Right-of-way documents dedicating to the drainage district all necessary easements and

right-of-ways for the new branches and/or extensions. Said documents must be in a

recordable form satisfactory to the Drain Commissioner and the County Register of

Deeds.

 Covenants or Restrictions attaching to each new lot in the subdivision clearly stating that

said lot is in the drainage district and subject to periodic special assessments for drain

maintenance.

 Updated special assessment roll reflecting all parcels within the district subject to drain

special assessments.

Subsequent to Drain Commissioner approval, the documents must be recorded, with the originals

returned to the Office of the Drain Commissioner.

Before commencing to do any work on the site, the proprietor shall make satisfactory

arrangements with the Commissioner to provide for the inspection of the project by the Drain

Commissioner. These arrangements shall include, among other things, the submission of three

sets of approved drainage plans, satisfactory evidence of insurance coverage, and a copy of the

signed contract between the proprietor and his Contractor covering the work to be performed.

Inspections by the Drain Commissioner shall not relieve the proprietor of his obligations. Spot

inspections by the Drain Commissioner's inspector are to verify the proper construction of the

drains in their various stages of completion. If it is necessary to retain a natural watercourse

because this watercourse serves land outside the proposed development, then recordable releases

for said watercourse will be submitted. The contract shall show in addition to the name of the

Contractor, the items of work involved, the total cost of the project, and the proposed completion

date. At the time this information is supplied to the Drain Commissioner, inspection deposits

shall be computed and payment of same shall be made to the Commissioner prior to

commencing work. The proprietor will be held responsible for the actual inspection costs

incurred by the Drain Commissioner. Before work commences, an inspector must be assigned to

the project. The inspector may, at his discretion, request that a pre-construction meeting of all

involved parties be held.

3.0 PLAT/PLAN REQUIREMENTS and PROCEDURES

Listed below are requirements and procedures for preliminary plats and plans, construction

plans, and final plats.

All submissions for review by the Drain Commissioner must be accompanied by an Application

for Drain Commissioner Review, which can be found in Appendix A. The application must

indicate the type of plat/plans being submitted and be signed and dated by the proprietor or the

proprietor's legal agent. The application grants permission for the Drain Commissioner or an

assigned representative to enter and inspect the site. A check, or equivalent, for the initial review

must accompany the application. Initial review fees are presented in Appendix B. These fees

are predicated upon the size of the proposed development. Plats/plans shall not be considered

"received" for review until the Application for Drain Commissioner Review is completed,

signed, and filed along with payment of initial review fees. Proprietors may be responsible for

additional fees if additional review time is necessary to perform a satisfactory review of the

plat/plans.

3.1 Preliminary Plat/Plan Requirements & Procedures

A preliminary plat is required for proposed residential and industrial subdivisions prior to

submission of construction plans. Preliminary plans are required for Manufactured Housing

Communities / Mobile Home Parks. Submission of preliminary plans is optional, but may be

required, for all other types of developments subject to review and approval of the Drain

Commissioner. If preliminary plans are submitted, they will be reviewed according to the same

requirements and standards as preliminary plats. All preliminary plat or plan approvals are

contingent upon approval of construction plans and other applicable provisions of the Rules.

With the submission of a preliminary plat or preliminary plans, the proprietor or assigned agent

must simultaneously submit to the Drain Commissioner:

 five copies of the preliminary plat/plans

 a letter of transmittal

 the Application for Drain Commissioner Review (See Appendix A)

 payment for initial review (See Appendix B)

 the completed Preliminary Plat/Plan Checklist (See Appendix F)

Preliminary plats/plans shall conform to the following requirements:

A. A preliminary plat or preliminary plans shall show the layout of the area intended to be

platted or developed. The plat or plans shall be prepared under the direction of a

registered engineer or a registered land surveyor, and shall be drawn to a scale not

smaller than 1 inch equal to 100 ft.

B. The preliminary plat or preliminary plans shall give the location of the proposed

subdivision/development with reference to the section and part of section in which the

parcel is situated and the name of the township, city, or village. The plat/plans shall

show the proposed street and alley layout, lot and plat/site dimensions, all pertinent

factors such as adjoining roads and subdivisions, rivers, railroads, high tension tower

lines or underground transmission lines, cemeteries, parks, natural watercourses,

established drains, sewers, easements, or any other feature, the existence, location, or

description of which might be of value in determining the overall requirements for the

subdivision/development. If the proposed plat/development is a part of or an addition to

an established county or inter-county drainage district, this fact shall be clearly stated and

the district boundaries shall be shown on the watershed map.

C. Easements for the public utilities shall be shown with the tentative layout. Inasmuch as

improper utility easement location can result in a change in plat/site layout, the proprietor

is advised to consult with the respective utility companies before presenting the tentative

layout for approval. Contour information shall be shown with a minimum of a 2-ft.

contour interval.

D. In the case where the proprietor wishes to develop a given area, but wishes to begin with

only a portion of the total area, the original plat/plans shall include the proposed general

layout for the entire area. The part that is proposed to be developed first shall be clearly

superimposed upon the overall plan in order to illustrate clearly the method of

development that the proprietor intends to follow. Each subsequent plat or set of

preliminary plans shall follow the same procedure until the entire area controlled by the

proprietor is subdivided. The final acceptance of a subdivision/development that is a

partial development of a larger general layout does not automatically ensure the final

acceptance of the overall layout. Each phase of the development will be required to have

adequate stormwater drainage and detention. Drainage plans for a phase of development

must not be dependent upon work planned to be performed in a future phase.

E. The names of the proprietor and engineering and/or surveying firm, with mailing

addresses and telephone numbers for each, shall be included.

F. If an established drain is involved, preliminary plats/plans shall include a note indicating

that “All work performed in the right-of-way of an established drain shall require a

permit from the Drain Commissioner.”

G. Accompanying each copy of the preliminary plat/plans shall be a copy of the site report

furnished to the Department of Health under their rule.

H. All wetlands and floodplains shall be delineated on preliminary plats or plans.

I. The seasonal high groundwater table elevation and basement floor elevations (if

applicable) shall be indicated on the preliminary plat or plans. Basement floors shall be

at least two feet above the seasonal high water table or a permanently controlled

groundwater level associated with a permanent gravity groundwater depression system.

J. The receiving watercourse to serve as the outlet for each proposed detention facility shall

be identified on the preliminary plat/plans. If the receiving watercourse identified is not

suitable to serve as the outlet, the proprietor may be required to improve the watercourse

to conditions approvable by the Drain Commissioner.

K. Careful consideration should be given to the design of detention and/or retention basins

during preparation of the preliminary plat/plans. Although design calculations for the

volume and size of detention or retention basins are evaluated as part of the construction

plan review, unidentified problems could result in significant modifications to the design

and/or site layout. Frequently overlooked problems include:

 Failure to provide adequate space for detention or retention basins, since

unrestricted discharge is not an acceptable option;

 Off-site areas contributing runoff onto a subject property affecting detention or

retention pond volume requirements;

 Intrusive floodplain elevations;

 Depth to groundwater as a constraint to a detention/retention basin’s depth; and

 Insufficient elevation change between a detention basin and its receiving

watercourse.

L. If the preliminary plat/plans have been revised and are being re-submitted, the letter of

transmittal shall indicate how the plat/plans have been revised and how each comment

from the Drain Commissioner’s previous review letter has been addressed.

M. When concentrated stormwater is proposed to be discharged over, onto, or across

property other than that owned by the proprietor, an easement or agreement between the

property owners must be executed and submitted to the Drain Commissioner in a form

acceptable to the Drain Commissioner.

N. If either the proprietor or the Drain Commissioner finds it advantageous to make changes

to a preliminary plat before the final plat is presented to the Commissioner for signature,

such changes can be made, provided that a new preliminary plat is submitted for with

each change in the layout. The proprietor is reminded that approval of a proposed

subdivision by the local governing body is also required under the Subdivision Control

Act. Changes made to obtain approval by the local governing body must be incorporated

into the layout and a new preliminary plat resubmitted even though the original layout

may have already been approved by the Drain Commissioner. If the proprietor does not

present his final plat to the Commissioner for approval within a period of two years after

receiving approval of the preliminary plat, it may be necessary that he resubmit the

preliminary plat for review in the light of new information that may have become

available during the interim.

3.2 Construction Plan Requirements and Procedures

Construction plans shall be reviewed subsequent to preliminary plat/plan reviews, if applicable.

With the submission of construction plans, the proprietor or assigned agent must simultaneously

submit the following to the Drain Commissioner:

 two copies of the construction plans

 a letter of transmittal

 the Application for Drain Commissioner Review (See Appendix A)

 payment for initial review (See Appendix B)

 the completed Construction Plan Checklist (See Appendix G)

 an agreement for maintenance of the stormwater management facilities (See Appendix H)

 any needed applications for permits to discharge to an established drain (Drainage

Permit) or appeals for inclusion within a drainage district (Section 433 Agreement)

 an agreement between land owners if concentrated stormwater is to be discharged onto

private property other than that owned by the proprietor

 a permit from the Michigan Department of Environmental Quality, if any construction

activities are proposed within regulated wetlands

Construction plans must meet the following requirements:

A. For developments required to submit a preliminary plat, the approved preliminary plat or

plans shall be incorporated into the constructions plans. For developments not required

to submit a preliminary plat, the construction plans shall conform to the requirements and

standards identified for preliminary plats/plans, items A-M in Section 3.1.

B. Construction plans must conform to the design standards presented in Section 4.0 Design

Standards for Stormwater Systems.

C. Except for developments that will ultimately be owned by a single proprietor (e.g.

commercial developments, mobile home parks, municipal developments), construction

plans will not be granted approval by the Drain Commissioner until a satisfactory

agreement has been submitted regarding long-term maintenance of the stormwater

management facilities, including the detention and/or retention basins. Examples of

acceptable maintenance agreements include:

 Resolution of Acceptance from the municipality (e.g. township, city, or village) or

other governmental agency with taxing powers indicating that the municipality or

governmental agency is willing to accept, maintain, and operate the proposed

stormwater management facilities on a permanent basis.

 Deed Restrictions for a subdivision indicating that the homeowners’ association will

accept, maintain, and operate the proposed stormwater management facilities on a

permanent basis.

 Master Deed for a condominium development indicating the condominium

association will accept, maintain, and operate the proposed stormwater management

facilities on a permanent basis.

Examples of such maintenance agreements can be found in Appendix H.

D. When concentrated stormwater is proposed to be discharged over, onto, or across private

property other than that owned by the proprietor, an agreement between the land owners

must be executed relieving the Drain Commissioner and municipality of any and all

responsibility for damage that might occur. Such an agreement shall be submitted to the

Drain Commissioner and municipality prior to construction.

3.3 Final Plat Requirements and Procedures

Final plats are required to be submitted for residential and industrial subdivision developments

only; all other types of developments are considered approved by the Drain Commissioner upon

approval of the construction plans. The Drain Commissioner's evaluation of final plats will

occur subsequent to construction plan approvals.

Five copies of the final plat shall be submitted to the Drain Commissioner. If approved, the

Drain Commissioner's signature will be affixed to the plats for execution. Six copies may be

submitted if the proprietor requests the return of a copy with the Drain Commissioner's signature.

The following requirements must be satisfied prior to final plat approval:

A. The final plat must strictly adhere to the construction plans as approved by the Drain

Commissioner.

B. The proprietor must submit a copy of the concerned municipality's approval of the

preliminary plat. The municipality’s approval shall be considered valid for two years

from the date of their approval.

C. The proprietor must submit a notarized letter in which the proprietor or assigned agent

attests to the fact that all necessary permits (e.g. Wetland, Floodplain, Inland Lakes and

Streams, Erosion Control, etc.) and required governmental approvals (e.g. Michigan

Department of Environment, Great Lakes & Energy (EGLE) Compliance Analysis

determination of adequacy, EGLE Baseline Environmental Assessment determination of

adequacy, EGLE risk assessment determination of adequacy, etc.) have been granted.

D. The proprietor's engineer shall furnish a certificate bearing a clear statement that all of the

drainage facilities within the subject plat have been constructed in accordance with the

approved construction plans and specifications (See Section 3.3.1 below), or, if the

construction has not been completed at the time of final plat submittal, the proprietor

must enter into an agreement with the Drain Commissioner and post surety for faithful

performance of the agreement (See Section 3.3.2 below).

3.3.1 Procedure for the Construction of Drainage Systems Prior to Final Plat Approval

If a drainage system is to be completed before submission of the final plat, the proprietor must

request the Drain Commissioner's inspection of the project. The Commissioner must receive an

Inspection Request Letter proposing an available time and date for inspection. Requested

inspection dates must be no less than 15 working days from the Drain Commissioner's receipt of

the request.

Approval of the final plat shall be contingent upon strict adherence to the construction plans as

approved in writing by the Drain Commissioner. The proprietor shall be responsible for cleaning

all sewers, manholes, catch basins, or other structures affected by the operations in the

development before final plat approval. The proprietor should take whatever precautions he

deems necessary in direct relations with his contractor in order to assure the work performed by

the contractor meets the approval of the Drain Commissioner. The proprietor shall be held

totally responsible for the fulfillment of his obligations to the Drain Commissioner

notwithstanding that his contractor or consulting engineer may be at fault. The proprietor may

be required to post a nominal bond with the Drain Commissioner to guarantee repairs of any

defects, which may show up as a result of poor workmanship or defective materials within one

year after completion of the improvements. Should no defects occur within this period of one

year and should no adjustments be required, this bond will be returned to the proprietor in its

entirety.

3.3.2 Procedure for Drainage Systems Constructed Subsequent to Final Plat Approval

As required under Section 192(b) of the Land Division Act, as amended; M.C.L. § 560.192(b), if

adequate stormwater facilities within the land proposed for platting are not installed before

approval of the final plat, the proprietor shall enter into an agreement with the governing body or

county drain commissioner and shall post a cash deposit, certified check or irrevocable bank

letter of credit whichever the proprietor selects, or a surety bond acceptable to the approving

authority, in an amount sufficient for the faithful performance of the agreement. A rebate shall be

made to the proprietor, as the work progresses, of amounts of any cash deposits equal to the ratio

of the work completed to the entire project.

Prior to the final release of surety money, the proprietor's engineer shall submit a complete set of

as-built drawings showing all of the approved field changes. The as-built drawings will be kept

on file with Drain Commissioner for permanent public record.

3.4 Other Permits & Requirements

3.4.1 Soil Erosion and Sedimentation Control Permit

The development may require a Soil Erosion and Sedimentation Control (SESC) Permit from the

County Enforcing Agency (St. Clair County Health Department) for Part 91, Soil Erosion &

Sedimentation Control, of the Natural Resources Environmental Protection Act (NREPA), Public

Act 451 of 1994, as amended.

SESC permit applications can be obtained from the St. Clair County Health Department:

St. Clair County Health Department

3415 28

Street

Port Huron, MI 48060

http://www.stclaircounty.org/Offices/health/SoilErosion.aspx

3.4.2 NPDES Permit-by-Rule

The development may require a National Pollutant Discharge Elimination System (NPDES)

Permit-by-Rule from the Michigan Department of Environment, Great Lakes & Energy (EGLE).

The (NPDES) Permit Program is the Construction Storm Water Coverage under Permit-by-Rule

under Part 31, Water Resources Protection of the Natural Resources and Environmental

Protection Act (NREPA), Public Act 451 of 1994, as amended and the Federal Water Pollution

Control Act, 33 U.S.C. 1251, et seq. (Clean Water Act)

NPDES permit applications for projects within St. Clair County should be submitted to the

following EGLE local district office:

Southeast Michigan District Office

27700 Donald Court

Warren, MI 48092

(586) 753-3700

3.4.3 Other Requirements

In any case where construction will occur within a County Drain Right of Way, the following

conditions also apply:

The facility shall be constructed at the location, elevation, and manner shown in the construction

drawings. All underground lines must be buried a minimum of 5 feet below the existing bottom

and side slopes of the drain unless a written agreement is reached between both parties stating

otherwise.

All work done in connection with the construction and the drain facility will be documented to

have been restored substantially to the working condition as designed.

Drainage shall be maintained and left unobstructed during construction so as to prevent the

backing up of water which would cause flooding of adjacent land.

The Developer assumes all liability for any loss or damage sustained by any person or property

as a result of operations performed by him and will repair any damage which it causes.

Documentation of the final condition will be provided to the St. Clair County Drain

Commissioner.

The Developer will notify the St. Clair County Drain Commissioner 48 hours prior to the

commencement of work and an inspector will be present while the work is in progress. Fees for

inspection by the St. Clair County Drain Commissioner will be the responsibility of the

Developer and the Developer agrees to pay the necessary expense of the Drain Commissioner’s

inspector. The cost of the Inspector shall be reflected in the budget for construction.

At the discretion of the St. Clair County Drain Commissioner, progress meetings may be

required for any work done within County Drain Right of Way. The Developer will prepare

agendas and publish minutes of the progress meetings to accurately record the proceedings.

An accurate record of facility construction in the form of scale drawings will be submitted to the

St. Clair County Drain Commissioner within 6 months of the completion of construction.

3.5 Procedures for Appeal of Decision of Drain Commissioner

If a proprietor, or other person aggrieved by a decision made by the Drain Commissioner

pursuant to these Rules, wishes to appeal the decision of the Drain Commissioner, such appeal

shall be made in writing to the St. Clair County Drain Commissioner within 20 calendar days of

the decision. Examples of decisions subject to these appeal procedures include, but are not

limited to, approvals or denials relating to plats, condominium developments, mobile home

developments, or other construction and development activities subject to 425 permits. The

written appeal shall identify which aspects of the decision of the Drain Commissioner are the

subject of the appeal, and should specify in detail the basis and rationale for the appeal. The

appellant may rely on the documentation previously presented to the Drain Commissioner or

may include any additional information or documentation to be considered by the Drain

Commissioner as part of the appeal. Additionally, the appellant may request an informal hearing

with the Drain Commissioner. If an informal hearing is requested, the Drain Commissioner will

schedule the hearing within 10 calendar days from the date of having received the appeal.

At the appeal hearing, the proprietor and/or its representatives shall be allowed an opportunity to

submit additional information or re-emphasize previously submitted data supporting positions

taken in their appeal; to further explain the nature and basis for the appeal; and/or to present an

alternative disposition for the decision appealed. Following the Drain Commissioner’s review of

the information presented during the appeal process, the Drain Commissioner shall make a final

decision on the appeal within 20 days of the appeal if no hearing is requested. If a hearing is

requested and held, the final decision shall be made within 20 days of the hearing. The final

decision of the Drain Commissioner shall be mailed to the proprietor by first class mail.

Undertaking an administrative appeal pursuant to these rules shall be a prerequisite to seeking

relief by way of filing court proceedings regarding the subject of the appeal, unless different

procedures are expressly provided under the Drain Code pertaining to decisions of the Drain

Commissioner or Drain Board or other applicable state laws.

4.0 DESIGN STANDARDS for STORMWATER

SYSTEMS

Unless otherwise noted, the following design standards and requirements apply to construction

plans submitted for review by the St. Clair County Drain Commissioner for all types of

developments or drain-related construction activities.

4.1 General Requirements

The following general stormwater management requirements apply to all new

developments and redevelopments in St. Clair County.

A. The design process shall begin by identifying sensitive areas located on the site and

laying out the site to protect the sensitive areas.

B. Best Management Practices (BMPs) that reduce the amount of stormwater runoff and

improve water quality are required and shall be designed on a site specific basis. Rate

and volume reduction BMPs shall be used to protect open channel storm drains. All

BMPs shall be included on the plans and will be subject to review and approval by

the SCCDO and EGLE as necessary for permits. BMP usage shall be monitored and

recorded in the weekly SESC reports. Areas with potential for significant pollutant

loading, as determined by the SCCDO, will require BMPs which address regulation

of the specific hazard.

The Developer/Owner shall include a long-term operation and maintenance schedule

for all permanent BMPs. A maintenance agreement between the SCCDO and the

owners, lessees, or operators is necessary for permanent BMPs which shall include

but not be limited to: inspection of structural or vegetative BMPs, performance of

maintenance and corrective actions when BMPs are neglected by the owner, and deed

restrictions. This document must be signed and have an email address so the SCCDO

can follow up as needed to ensure maintenance is being completed. There must also

be a statement that the owner will notify the SCCDO of any sale or transfer of

ownership on the property. This can also be done by the use of deed restriction

language for subdivisions or through residential and industrial condominium project

documents.

C. Onsite management of stormwater is required first and foremost, unless site

constraints preclude this approach.

D. Stormwater shall be managed using four standards: stream protection, flood control,

water quality and pre-treatment to protect both water resources and real property.

E. Stream protection (channel protection/bankfull flood) shall be provided for surface

water discharges to natural water courses (directly or through pipes or ditches) by

retaining onsite the difference in stormwater runoff volume between pre-development

and post-development conditions for the 2-year, 24 hour storm (2.30 inches of rain).

Stream protection for redevelopments shall be provided through retention of the

difference in the 2-year 24-hour stormwater runoff volume between existing and post-

development conditions. If extended detention is considered, refer to section 1.3.1 for

Source Controls. The design engineer must consider incorporation of green

infrastructure elements and keep in mind that if extended detention is to be used, then

additional BMPs likely will be needed to maintain pre-development volume and peak

flow rate levels for all storms up to the 2-year 24 hour event. The discharge rate from

the proposed site cannot exceed 0.15 cfs/acre. The developer will need to provide

extended detention for the portion of runoff from the 2-year 24-hour storm that

cannot be removed on site and discharge at the runoff rate of 0.15 cfs/acre. Examples

of BMPs include but are not limited to green roofs, rain gardens, bio retention, bio

swales, removal of impervious area, or use of trees and various shrubs.

F. Flood control shall be provided for all sites through retention or detention. One inch

of runoff from disturbed pervious and impervious areas should be detained for

treatment and flood control. The maximum allowable detention release rate is equal

to the presettlement runoff rate for all storms up to the 100 year storm event using the

Runoff Curve Number Method to determine presettlement runoff. The maximum

allowable release rate shall be 0.15 cfs per acre. Onsite flood control may be waived

for direct discharges to large lakes and rivers if the Developer demonstrates no

negative impacts, or if provided in a regional facility with adequate upstream

infrastructure.

G. Overland flow routes and the extent of high water levels for the 100-year storm shall

be identified for all sites.

H. Water quality treatment shall be provided for all sites. A minimum treatment volume

equal to one inch of runoff from the directly contributing impervious area is required.

A minimum volume of 900 cubic feet per acre is required for directly connected

disturbed pervious areas (i.e. lawns). BMP’s shall be designed to reduce post

development solids loadings by 80% or to not exceed solids loadings of 80

milligrams per liter.

I. Pre-treatment is required for infiltration, filtration and detention BMPs for ease of

maintenance and to protect BMP integrity and preserve longevity.

J. Stormwater discharges from activities with a high risk for an accidental spill of

pollutants (stormwater hot spots) shall provide spill containment.

K. Stormwater discharges to cold water streams shall employ management strategies to

reduce stormwater runoff temperature and promote groundwater recharge.

L. The design maximum release rate, volume or concentration of stormwater discharged

from a site shall not exceed the capacity of existing infrastructure or cause

impairment to the offsite receiving area. Evaluation of the existing outlet must be

performed and an adequate outlet must be provided.

M. The use of many decentralized Low Impact Development (LID) BMPs is not

mandated, but is encouraged on private sites.

N. Construction plans for a phased development shall show the existing and/or proposed

drainage systems for all prior phases of the development, unless the drainage system

for the current phase is entirely independent of the prior phases. Furthermore,

drainage plans for a phase of a development must not be dependent upon work

planned to be performed in a future phase.

O. Plans shall include a grading plan showing existing and proposed topographic contour

lines and proposed finish floor and basement floor elevations.

P. All existing natural or manmade watercourses shall be shown on the plans. The

proposed changes to the site must not interfere with Common Law Natural Flow

Rights. Existing watercourses must be preserved or relocated, or the flow otherwise

accommodated by the proposed plans. Provisions for the maintenance of the

watercourse must be included in the deed restriction or an equivalent legally binding

agreement. EGLE and/or the Army Corp. of Engineers may also require permits for

changes made to such watercourses.

Q. No construction activities shall be allowed without approval of the Drain

Commissioner in a 100-year floodplain as determined by the Drain Commissioner.

R. The cover sheet of the plans shall include a “Permit Status Table” indicating the

status of all permits being obtained. An example of such a table is provided in

Appendix E.

S. If an established drain is involved, construction plans shall include a note indicating

that “All work performed in the right-of-way of an established drain shall be in

accordance with the Drain Commissioner’s Rules.”

T. The engineer's seal shall be affixed to all sheets of the construction plans.

4.2 Established Drains

A. Plans shall include plans and profiles of all existing and proposed drains within road

right-of-way and drainage easements on site. These drawings shall indicate the channel

bottom, banks, base flow water elevation, and the location of the outlet from the

detention facility, if applicable.

B. Minimum right-of-way widths for proposed drains:

1. Proposed open drains shall have a minimum right-of-way of 40 feet plus top width of

channel centered on drain centerline. A consistent right-of-way width shall be

maintained along the entire reach of drain on the proposed site. A minimum width of

20 feet must be maintained from the top-of-bank to the edge of the right-of-way to

allow for maintenance of the drain.

2. Proposed enclosed drains shall have a minimum right-of-way of 40 feet centered on

the centerline of the enclosure.

3. The above minimum widths shall govern generally; however, wider right-of-ways

may be required at the discretion of the Commissioner.

C. Where drainage is to be discharged to an established drain, either directly or through

secondary routes, the drain shall be improved to standards approved by the Drain

Commissioner when necessary for proper drainage of the proposed development. The

drain restoration can be performed by and/or at the expense of the Developer (See

Section 2.8), or by the Drain Commissioner by means of a petition to clean out the drain.

D. Where drainage is discharged to an established drain, the outlet shall be so designed as to

enter the drain at an angle of 90 degrees or less, as determined by the upstream centerline.

Preformed end sections, grouted riprap, or specially designed outlet structures will be

required.

E. If cutting and/or filling is to be performed within a drain right-of-way, a table shall be

provided indicating at one-foot elevation intervals the total cut and fill volumes below

each elevation. At each one-foot elevation interval, the total cut volume must equal or

exceed the total fill volume. (Note that additional permit(s) may be required from

EGLE).

F. Sodding, seeding, and mulching within a drain right-of-way shall be done in accordance

with the requirements of the “Soil Erosion and Sedimentation Control, Authorized Public

Agency Procedures Manual” of the St. Clair County Drain Commissioner, and performed

only after prior approval of the Drain Commissioner as to the time of performance and

acceptability of the finished grade. This work must be performed under the inspection of

the Drain Commissioner.

4.3 Storm Sewers

A. Plans shall show boundaries and acreages of catchment areas contributing runoff to each

proposed or existing catch basin and/or inlet. Runoff from off-site tributary areas must be

accommodated in design or rerouted.

B. The required discharge capacity for each reach of sewer shall be determined by the

Rational Method.

1. A 10-year design storm shall be used such that rainfall intensity, I = 175 / (T + 25),

where T = time of concentration in minutes.

2. The runoff coefficient, C, shall be in conformance will normal design practice. Where

a weighted average coefficient is employed, the computations shall be submitted for

review.

C. A complete set of storm sewer design calculations shall accompany every set of

construction plans submitted for review.

1. Sewer capacities shall be based on the Manning equation.

2. Energy losses from friction shall be based on calculated design storm peak discharges

and velocities, not Manning design (i.e. full-pipe) capacities.

3. Energy losses from friction shall be based on typical Manning “n” roughness values

as shown in Table J-3.

4. Energy losses through manholes and other appurtenances shall be included in the

design calculations OR reflected in friction losses through use of conservative

Manning “n” roughness values as shown in Table J-3.

D. The storm sewer pipe shall have a minimum diameter of 12 inches when constructed in a

public right-of-way or easement.

E. Storm sewer slopes must not be flatter than the minimum slopes indicated in Table J-2.

F. Minimum allowable pipe velocity shall be 2.5 ft/sec. (except where the minimum

diameter requirement makes this unachievable.) Desirable pipe velocity range shall be 4-

8 ft/sec. Maximum allowable pipe velocity shall be 10 ft/sec.

G. Hydraulic grade lines shall be calculated and shown as a part of all storm sewer profiles.

In no case shall the hydraulic grade line exceed the elevation lying 1 foot below the rim

elevation of a manhole, catch basin or inlet. The hydraulic grade line upstream of a

detention or retention storage facility shall be calculated assuming the design high water

elevation (e.g. full detention basin).

H. The storm sewer plan and profile drawing shall show the following data:

1. Proper identification and numbering of manholes, catch basins and inlets

2. Invert and casting elevations for all structures

3. Pipe length (C/L to C/L to structures)

4. Pipe diameter

5. Pipe slope

6. Pipe class or designation

7. Detail of trench construction and type of backfill material

I. Generally, manholes shall be placed not more than 400 feet apart for sewers less than 30

inches diameter and 600 feet apart for larger sewers.

J. The minimum inside diameter of all manholes, catch basins and inlets shall be 48 inches,

with the following exception: Inlet structures from which water will be discharged

directly into a catch basin may be 24 inches inside diameter. The depth of such inlets

shall be no greater 5.0 feet and no less than 3.5 feet from the top of frame and cover to

the invert.

K. Manholes and inlets structures may be constructed of brick, manhole block, precast

concrete (ASTM C478) or cast-in-place concrete.

L. All manhole block or brick structures shall be plastered on the outside with 1 to 2.5 mix

of portland cement mortar, ½-inch thick. No calcium chloride or other chemical shall be

added to lower the freezing point of the mortar, as the strength of the mortar may be

lessened.

M. Inlet structures in the public street right-of-way shall be spaced a maximum of 400 feet

apart (or a maximum of 400 feet on either side of a high point). The spacing and/or

number of inlet structures required to accommodate the design flows in streets and in

private drives and parking areas, shall be based on a maximum of 1 cfs per 90 square

inches of opening in an inlet or catch basin cover.

N. All storm sewer pipe, manholes, catch basins, and inlets shall meet MDOT specifications.

O. Generally, drops of over 2.0 feet at manholes, from invert of higher pipes to lower pipes,

shall be avoided.

P. Joints in concrete pipe having a diameter of 30 inches or larger shall be pointed up on

inside with mortar after backfilling has been completed.

Q. Where drainage is discharged to an established drain or natural watercourse, such outlets

shall enter the drain or watercourse at an angle of 90 degrees or less, as measured from

the upstream centerline. Preformed end sections, riprap or specially designed outlet

structures will be required.

R. Unless the storm sewers are to be owned and maintained by a single private entity (i.e.

municipal or commercial development, manufactured housing community, etc.), all storm

sewers shall be located within an easement. The minimum easement width for a storm

sewer shall be 40 feet centered on the sewer centerline.

S. All existing and proposed on-site drainage easements shall be clearly shown.

T. If any utilities are to be located within existing or proposed drainage easements within a

development, the proprietor's engineer shall present plans of such utilities to the Com-

missioner for his approval as to location. If possible, such plans should be presented at

the same time as drainage plans so that all details of construction and location may be

checked and properly oriented with each other. In order to avoid conflict, it is important

that a careful investigation be made where underground utilities are in close proximity to

proposed storm sewers, or where they cross each other.

4.4 Open Channels

NOAA Atlas 14, “Precipitation–Frequency Atlas of the United States” (2013) is

considered the most current and comprehensive rainfall data available. The National

Oceanic & Atmospheric Administration’s Atlas 14 data can be accessed at:

https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html

In the recent past, rainfall data compiled by Huff, F.A. and Angel, J.R. was commonly

used. See: Rainfall Frequency Atlas of the Midwest, 1992, Bulletin 71 Midwestern

Climate Center and Illinois State Water Survey. MCC Research Report 92-03, available

for free download at: http://www.sws.uiuc.edu/pubdoc/B/ISWSB-71.pdf

Long-term daily and monthly precipitation data for about 25 stations throughout

Michigan is available free from the United States Historical Climatology Network

(USHCN) at: http://cdiac.ornl.gov/epubs/ndp/ushcn/ushcn_map_interface.html

A. The peak 10-year flow in each reach of open channel shall remain within the banks of the

channel. Off-site tributary area shall be included in the design, or the off-site tributary

runoff shall be rerouted around the channel.

B. The values of Manning's "n" shall be no less than 0.040 except where the channel is

smooth and paved in which case an "n" value of 0.013 to 0.022 shall be used.

C. The maximum velocity for grass lined channels shall not exceed 5 ft/sec. Where above

velocity is exceeded, the channel shall be protected by cobble paving or other means to

prevent scour.

D. The minimum acceptable non-siltation velocity should be 1.5 ft/sec.

E. Unless the open channels are to be owned and maintained by a single private entity (i.e.

industrial/commercial development, manufactured housing community, etc.), all open

channels shall be located within an easement. Open channels shall have a minimum

right-of-way of 40 feet plus top width of channel centered on the centerline. A consistent

right-of-way width shall be maintained along the entire reach of channel on the proposed

site. A minimum width of 20 feet must be maintained from the top-of-bank to the edge

of the right-of-way to allow for maintenance. The above minimum width shall govern

generally; however, wider right-of-ways may be required at the discretion of the

Commissioner.

F. Side slopes of open channels shall normally be no steeper than 1 vertical to 3 horizontal.

Where conditions dictate steeper side slopes, consideration should be given to slope

paving and fencing. The final decision in such matters rests with the Drain

Commissioner.

G. All existing and proposed on-site drainage easements shall be clearly shown on the plans.

4.5 Culverts

A. All culverts should be labeled on the plans as “existing”, “proposed”, or “to be

extended”.

B. Plans shall show boundaries and acreages of tributary areas contributing runoff to each

proposed or existing culvert on the proposed site.

C. Proposed or extended culverts on established county drains must be approved by the

Drain Commissioner. Proposed or extended culverts may also require the approval of the

Michigan Department of Environment, Great Lakes & Energy (EGLE), the St. Clair

County Road Commission and/or the Michigan Department of Transportation (MDOT).

Copies of permits obtained from other agencies must be submitted to the St. Clair County

Drain Commissioner.

D. If the tributary area to a culvert is less than 20 acres, the Rational Method shall be used to

determine the peak design flow for the culvert. For larger tributary areas, the SCS

Method shall be used. The runoff coefficients used should be consistent with those in

Table J-1, and selected to reflect the future land use of the tributary area.

E. All culverts shall be designed for inlet and outlet control conditions. Calculations of the

10-year and 100-year headwater elevations shall accompany the final plans (see

Appendix N for Example Culvert Design Calculation).

1. The 10-year headwater elevation of each culvert shall not exceed an elevation one

foot below the road or driveway centerline elevation. The backwater shall not extend

beyond the limits of the proprietor’s property.

2. The 100-year headwater elevation of each culvert may overtop the road or driveway

centerline elevation, but must remain below proposed finish floor elevations of all

nearby existing and proposed structures.

3. The tailwater elevation assumed for each culvert should be estimated as the normal

depth of the peak flow in the downstream channel, unless the tailwater is influenced

by the headwater of another downstream culvert or the confluence of another

watercourse.

F. Wing walls, headwalls, end sections, and all other culvert extremities shall be designed to

ensure the stability of the surrounding soil, and to meet the requirements of other

governing agencies (e.g. St. Clair County Road Commission, MDOT, EGLE).

G. Roadways over culverts or bridges may be required to be paved or designed in such a

way as to prevent the erosion of road material into the established drain or watercourse.

H. The following data shall be provided for all proposed or extended culverts:

 Length

 Diameter

 Invert elevations

 Material type

 Protection for culvert ends

I. Riprap must be provided for all culverts in established drains or significant watercourses.

The rip-rap provided for the protection of culvert ends shall:

1. Extend at least one culvert diameter upstream of the culvert inlet and at least four

culvert diameters downstream of the culvert outlet;

2. Extend across the bottom of the channel and up the banks of the channel to at least

the elevation of the crown of the culvert;

3. Be inlayed such that it does not cause an obstruction in the watercourse; and

4. Have a minimum dimension no smaller than that consistent with HEC-11 Design

Guidelines for Rock Riprap and MDOT standards. (A conservative guideline for

water depths less than 3 feet would be to use 8-inch diameter riprap for flow

velocities up to 6 feet/sec, and 16-inch diameter riprap for flow velocities up to 11

feet/sec.)

J. Minimum diameter for a driveway or crossroad culvert shall be 18 inches or equivalent

pipe arch.

K. The pipe used in culverts shall meet MDOT specifications and St. Clair County Road

Commission standards.

4.6 Bioretention

A bioretention system consists of a soil bed planted with native vegetation located above an

underdrained sand layer. It can be configured as either a bioretention structure or a bioretention

swale. Stormwater runoff entering the bioretention system is filtered first through the vegetation

and then the sand/soil mixture before being conveyed downstream by the underdrain system.

Runoff storage depths above the planting bed surface are typically shallow. The adopted TSS

removal rate for bioretention systems is 90 percent.

Bioretention systems are used to remove a wide range of pollutants, such as suspended solids,

nutrients, metals, hydrocarbons, and bacteria from stormwater runoff. They can also be used to

reduce peak runoff rates and increase stormwater infiltration when designed as a multi-stage,

multi-function facility.

4.6.1 Pre-Design Site Evaluation

Each specific site proposed for development or re-development is unique due to soils, land cover,

topography, location, land use and many other variables. These unique characteristics make it

difficult, if not impossible, to develop one set of uniform storm water standards which can

accommodate all variables. Due to this parameter, additional requirements not included in these

standards may be necessary to meet the intent of these rules. Also, waivers and variances from

certain provisions of these design standards or rules may be requested when it can be determined

that the standard cannot be feasibly accommodated. In these situations, alternatives consistent

with the overall intent of these rules may be proposed for consideration and will be subject to the

approval of the St. Clair County Drain Commissioner. For example, if there is an underdrain

sand filtration system in place to completely filter all runoff from this system, then the first flush

treatment criteria can be disregarded. During the review of the final submittal, if the design

meets applicable volume and water quality standards and any applicable discharge criteria, it can

be approved by the Drain Commissioner’s engineer or designee.

Soil borings and/or soil test pits may be required to determine the feasibility of infiltration. Also,

the design engineer must research the soils in the area of development/re-development and

determine the hydrologic soil groups (HSG - A, B, C, or D) and soil characteristics. The

majority of the Urbanized Area of St. Clair County does not have very permeable soils and the

soils are mainly type C and D soils. If the site has had previous soils borings and BMPs in place

which have functioned well in the past and can currently meet the 0.25 inches per hour

infiltration rate, or if the soils map and soil profile show an area which is conducive to

infiltration, then new soil borings may not be required. The need for soil borings will be

determined by the Drain Commissioner’s engineer or designee.

Another aspect to be cognizant of when implementing infiltration practices is the buildings on

the perimeter of a site development. The design engineer must consider basements nearby or

other buildings which may be adversely impacted by an infiltration practice being implemented

in an area with a clay layer just a few feet under the soils which prevents effective infiltration.

The bio-retention filtration collection system with its sand filtration system will slow the

discharge rates considerably and will lower the peak discharge rates. The peak discharge rate

from these systems cannot exceed the 2-yr 24-hr discharge from the site, so as to meet channel

protection standards.

For infiltration trench and structure practices, the following infiltration (K

SAT

) values shall be

used:

 K

sat

≥ 0.50 inches/hour

Infiltration BMPs shall be constructed to provide the infiltration volume as calculated

using the above requirements.

 0.24 inches/hour < K

sat

< 0.50 inches/hour

Install supplemental measures, which may include subsoil amendment, or an

underdrain placed at the top of the storage bed layer to ensure dewatering in the event

underlying soils fail to provide adequate drawdown/dewatering time. If underdrains

are selected, they shall be designed to allow stormwater to percolate through the soils

first, with the underdrain serving as a secondary outlet, by placing the underdrain in

the upper level of the BMP, with pipe perforations located along the underdrain

invert.

 K

sat

< 0.24 inches/hour

Soils are not suitable for infiltration. Alternative methods to reduce stormwater

volume shall be used.

Feasibility testing is to be conducted to screen unsuitable sites, and reduce testing costs. A soil

boring is not required at this stage. However, a designer or landowner may opt to engage

Concept Design Borings at his discretion, without feasibility testing.

Initial testing involves either one field test per facility, regardless of type or size, or previous

testing data, such as the following:

* on-site septic percolation testing, within 200 feet of the proposed BMP location, and on

the same contour which can establish initial rate, water table and/or depth to bedrock,

* geotechnical report on the site prepared by a qualified geotechnical consultant, or

* Natural Resources Conservation Service (NRCS) County Soil Mapping showing an

unsuitable soil group such as a hydrologic group “D” soil in a low-lying area.

Soil information can be found at this website:

https://websoilsurvey.nrcs.usda.gov/app/HomePage.htm

If the results of initial feasibility testing as determined by a qualified professional show that an

infiltration rate of greater than 0.24 inches per hour is probable, then the Drain Commissioner’s

engineer or designee shall make the final decision on implementation.

Once all testing is completed the design engineer must contact the St. Clair County Drain

Commissioner’s engineer to review the results for the site and determine if the proposed BMP is

a feasible practice for the development/re-development.

Technical Infeasibility

For projects where technical infeasibility exists, the design engineer must document and quantify

that stormwater strategies, such as infiltration, evapotranspiration, and harvesting and water use

have been used to the maximum extent technically feasible (METF) and that implementation of

these methods are infeasible due to site constraints. The burden of proof of technical infeasibility

lies with the design engineer. Documentation of technical infeasibility should include, but may

not be limited to, engineering calculations, geological reports, hydrological analyses and site

maps. A determination that the performance design goals cannot be achieved on the site should

include analyses that rule out the use of an adequate combination of infiltration,

evapotranspiration, and water use measures. Adequate documentation must be submitted to the

St. Clair County Drain Office for review and final determination. Examples of site conditions

that may prevent the application of stormwater BMP’s to the METF include (adapted from EPA

Section 438 Technical Guidance, December 2009):

 The conditions on the site preclude the use of infiltration practices due to the presence of

shallow bedrock, hard clay horizons, contaminated soils, high ground water or other

factors, such as underground facilities, utilities or location of the development within a

wellhead protection area.

 The design of the site precludes the use of soil amendments, plantings of vegetation or

other designs that can be used to infiltrate and evapotranspirate stormwater runoff.

 Water harvesting and use are not practical or possible because the volume of water used

for irrigation, toilet flushing, industrial make-up water, wash-waters, etc. is not

significant enough to warrant the design and use of water harvesting and use systems.

 Modifications to an existing building to manage stormwater are not feasible due to

structural or plumbing constraints or other factors.

 Site area is too small to accommodate adequate infiltration practices for the impervious

area to be served.

 Soils cannot be sufficiently modified to provide reasonable infiltration rates.

 Site use is inconsistent with the capture and use of stormwater or other physical

conditions on site that preclude the use of plants for evapotranspiration or bio-infiltration.

 Retention and/or use of stormwater onsite or discharge of stormwater onsite by

infiltration would have an adverse effect on the site, the down gradient surface or

subsurface water or receiving watershed or water body ecological processes.

 Federal, state, or local requirements or permit conditions prohibit water collection or

make it technically infeasible to apply LID practices.

4.6.2 Design Criteria

A. Storage Volume, Depth, and Duration

Bioretention systems shall be designed to treat the runoff volume generated by the

stormwater quality design storm (2 year). The maximum water depth during treatment

of the stormwater quality design storm shall be 12 inches in a bioretention structure and

18 inches in a bioretention swale. The minimum diameter of any outlet or overflow

orifice is 2.5 inches. The bottom of a bioretention system, including any underdrain

piping or gravel layer, must be a minimum of 2 feet above the seasonal high groundwater

table. The planting soil bed and underdrain system shall be designed to fully drain the

stormwater quality design storm runoff volume within 72 hours. The distance from the

bottom of the bioretention system to the seasonal high groundwater level is recommended

to be four (4) feet. Two feet is allowable, but may reduce the performance of the BMP.

B. Permeability Rates

The design permeability rate through the planting soil bed must be sufficient to fully

drain the stormwater quality design storm runoff volume within 72 hours. This

permeability rate must be determined by field or laboratory testing. Since the actual

permeability rate may vary from test results and may also decrease over time due to soil

bed consolidation or the accumulation of sediments removed from the treated stormwater,

a factor of safety of two shall be applied to the tested permeability rate to determine the

design permeability rate. Therefore, if the tested permeability rate of the soil bed material

is 4 inches/hour, the design rate would be 2 inches/hour (i.e., 4 inches per hour/2). This

design rate would then be used to compute the system’s stormwater quality design storm

drain time.

C. Planting Soil Bed

The planting soil bed provides the environment for water and nutrients to be made

available to the vegetation. The soil particles can adsorb some additional pollutants

through cation exchange, and voids within the soil particles can store a portion of the

stormwater quality design storm runoff volume. The planting soil bed material should

consist of 10 to 15 percent clays, a minimum 65 percent sands, with the balance as silts.

The material’s pH should range from 5.5 to 6.5. The material shall be placed in 12 to 18

inch lifts. The total depth or thickness of the planting soil bed should be a minimum of 3

feet. As noted above, the design permeability rate of the soil bed material must be

sufficient to drain the stormwater quality design storm runoff volume within 72 hours.

Filter fabric should be placed along the sides of the planting soil bed to prevent the

migration of soil particles from the adjacent soil into the planting soil bed.

D. Vegetation

The vegetation in a bioretention system removes some of the nutrients and other

pollutants in the stormwater inflow. The use of native plant material is recommended for

bioretention systems wherever possible. The goal of the planting plan should be to

simulate a forest-shrub community of primarily upland type. In general, trees should

dominate the perimeter zone that is subject to less frequent inundation. Shrubs and

herbaceous species that are adapted to moister conditions and expected pollutant loads

should be selected for the wetter zones. The number of stems per acre should average

1,000, with tree spacing of 12 feet and shrub spacing of 8 feet.

E. Sand Layer

The sand layer serves as a transition between the planting soil bed and the gravel layer

and underdrain pipes. It shall be a minimum thickness of 12 inches and consist of clean

medium aggregate sand (AASSHTO M-6/ASTM C-33 or MDOT Class II). To ensure

proper system operation, the sand layer must have a permeability rate at least twice as

fast as the design permeability rate of the planting soil bed.

F. Underdrain

The underdrain piping must be rigid Schedule 40 PVC pipe. The portion of drain piping

beneath the planting soil bed and sand layer must be perforated. All remaining underdrain

piping, including cleanouts, must be nonperforated. All joints must be secure and

watertight. The underdrain piping must connect to a downstream storm sewer manhole,

catch structure, channel, swale, or ground surface at a location that is not subject to

blockage by debris or sediment and is readily accessible for inspection and maintenance.

Blind connections to downstream storm sewers are prohibited.

G. Overflows

All bioretention systems must be able to safely convey system overflows to downstream

drainage systems. The capacity of the overflow must be consistent with the remainder of

the site’s drainage system and sufficient to provide safe, stable discharge of stormwater in

the event of an overflow.

H. Tailwater

The hydraulic design of the underdrain and overflow systems, as well as any stormwater

quantity control outlets, must consider any significant tailwater effects of downstream

waterways or facilities. This includes instances where the lowest invert in the outlet or

overflow structure is below the flood hazard area design flood elevation of a receiving

stream.

Bioretention systems must be constructed off-line from County Drains.

I. Maintenance

The following requirements must be included in the system’s maintenance plan.

1. General Maintenance

All bioretention system components expected to receive and/or trap debris and

sediment must be inspected for clogging and excessive debris and sediment

accumulation at least four times annually as well as after every storm exceeding 1

inch of rainfall. Such components may include bottoms, trash racks, low flow

channels, outlet structures, riprap or gabion aprons, and cleanouts.

Sediment removal should take place when the structure is thoroughly dry. Disposal of

debris, trash, sediment, and other waste material should be done at suitable

disposal/recycling sites and in compliance with all applicable local, state, and federal

waste regulations.

2. Vegetated Areas

Mowing and/or trimming of vegetation must be performed on a regular schedule

based on specific site conditions. Grass should be mowed at least once a month

during the growing season. Vegetated areas must be inspected at least annually for

erosion and scour. Vegetated areas should also be inspected at least annually for

unwanted growth, which should be removed with minimum disruption to the planting

soil bed and remaining vegetation.

When establishing or restoring vegetation, biweekly inspections of vegetation health

should be performed during the first growing season or until the vegetation is

established. Once established, inspections of vegetation health, density, and diversity

should be performed at least twice annually during both the growing and non-growing

seasons. The vegetative cover should be maintained at 85 percent. If vegetation has

greater than 50 percent damage, the area should be reestablished in accordance with

the original specifications and the inspection requirements presented above.

All use of fertilizers, mechanical treatments, pesticides and other means to assure

optimum vegetation health should not compromise the intended purpose of the

bioretention system. All vegetation deficiencies should be addressed without the use

of fertilizers and pesticides whenever possible.

3. Structural Components

All structural components must be inspected for cracking, subsidence, spalling,

erosion, and deterioration at least annually.

4.7 Infiltration

An infiltration structure is a facility constructed within highly permeable soils that provides

temporary storage of stormwater runoff. An infiltration structure does not normally have a

structural outlet to discharge runoff from the stormwater quality design storm. Instead, outflow

from an infiltration structure is through the surrounding soil. An infiltration structure may also be

combined with an extended detention structure to provide additional runoff storage for both

stormwater quality and quantity management. The adopted TSS removal rate for infiltration

structures is 80 percent.

Infiltration structures are used to remove pollutants and to infiltrate stormwater back into the

ground. Such infiltration also helps to reduce increases in both the peak rate and total volume of

runoff caused by land development. Pollutant removal is achieved through filtration of the runoff

through the soil as well as biological and chemical activity within the soil.

4.7.1 Pre-Design Site Evaluation

Infiltration structures can present some practical design problems. When planning for an

infiltration structure that provides stormwater quality treatment, consideration should be given to

soil characteristics, depth to the groundwater table, sensitivity of the region, and runoff water

quality. Specifically, infiltration structures must not be used in the following locations:

• Industrial and commercial areas where solvents and/or petroleum products are loaded,

unloaded, stored, or applied or pesticides are loaded, unloaded, or stored.

• Areas where hazardous materials are expected to be present in greater than “reportable

quantities” as defined by the U.S. Environmental Protection Agency in the Code of

Federal Regulations at 40 CFR 302.4.

• Areas where infiltration structure use would be inconsistent with an NJDEP-approved

remedial action work plan or landfill closure plan.

• Areas with high risks for spills of toxic materials such as gas stations and vehicle

maintenance facilities.

• Areas where industrial stormwater runoff is exposed to “source material.” “Source

material” means any material(s) or machinery, located at an industrial facility, that is

directly or indirectly related to process, manufacturing, or other industrial activities, that

could be a source of pollutants in any industrial stormwater discharge to groundwater.

Source materials include, but are not limited to raw materials, intermediate products, final

products, waste materials, by-products, industrial machinery and fuels, and lubricants,

solvents, and detergents that are related to process, manufacturing, or other industrial

activities that are exposed to stormwater.

• Areas where their installation would create a significant risk for basement seepage or

flooding, cause surficial flooding of groundwater, or interfere with the operation of

subsurface sewage disposal systems and other subsurface structures. Such adverse

impacts must be assessed and avoided by the design engineer.

If any of the above mentioned conditions are present, the SCCDO will coordinate with EGLE as

appropriate in the matters regarding the site to implement infiltration BMPs to manage

stormwater on a site with contaminated soils or similar issues.

Infiltration structures must be configured and located where their construction will not compact

the soils below the structure. In addition, an infiltration structure must not be placed into

operation until the contributing drainage area is completely stabilized.

General Setback Requirements for Infiltration Structures:

Soil Absorption Systems for Title 5 Systems: 50ft.

Private wells: 100 ft.

Public wells: 150 ft.

Public reservoir, surface water sources for public water systems and their tributaries: 400

ft.

Other surface waters: 50 ft.

Property Lines: 10 feet

Building foundations: >10 to 100 ft, depending upon soil types and Infiltration Structure

type

Soils are perhaps the most important consideration for site suitability. In general, County Soil

Surveys can be used to obtain necessary soil data for the planning and preliminary design of

infiltration structures. For final design and construction, soil tests are required at the exact

location of a proposed structure in order to confirm its ability to function without failure.

Tests should include:

 determination of the textural classification

 permeability of the subgrade soil at and below the bottom of the proposed

infiltration structure

The recommended minimum depth for subgrade soil analysis is 5 feet below the bottom of the

structure or to the groundwater table. Soil permeability testing can be conducted in accordance

with the Standards for Individual Subsurface Sewage Disposal Systems.

4.7.2 Design Criteria

A. Storage Volume, Depth, and Duration

An infiltration structure must be designed to treat the total runoff volume generated by

the structure’s maximum design storm. This may either be the groundwater recharge or

stormwater quality design storm, depending upon the structure’s proposed use. An

infiltration structure must also fully drain this runoff volume within 72 hours. Runoff

storage for greater times can render the structure ineffective and may result in anaerobic

conditions, odor, and both water quality and mosquito breeding problems. The bottom of

the infiltration structure must be at least 2 feet above seasonal high water table or

bedrock. For surface structures, this distance must be measured from the bottom of the

sand layer. The structure bottom must be as level as possible to uniformly distribute

runoff infiltration over the subgrade soils.

To enhance safety by minimizing standing water depths, the vertical distance between the

structure bottom and the maximum design storm water surface in surface infiltration

structures should be no greater than 2 feet. Construction of an infiltration structure must

be done without compacting the structure’s subgrade soils. Excavation must be

performed by equipment placed outside the structure whenever possible. This

requirement should be considered when designing the dimensions and total storage

volume of an infiltration structure. It is important to note that the use of infiltration

structures is recommended only for the stormwater quality design storm and smaller

storm events. Use of infiltration structures for larger storm events and the requirements

by which such structures are to be designed, constructed, and maintained should be

reviewed and approved by all applicable reviewing agencies.

B. Permeability Rates

The minimum design permeability rate of the soils below an infiltration structure will

depend upon the structure’s location and maximum design storm. The use of infiltration

structures for stormwater quality control is feasible only where soil is sufficiently

permeable to allow a reasonable rate of infiltration. Therefore, infiltration structures

designed for storms greater than the groundwater recharge storm can be constructed only

in areas with Hydrologic Soil Group A and B soils.

Maximum Design Structure Location Minimum Design Permeability Rate

(Inches/Hour)

Groundwater Recharge Subsurface 0.2

Groundwater Recharge Surface 0.5

Stormwater Quality Surface and Subsurface 0.5

In addition to the above, the design permeability rate of the soil must be sufficient to fully

drain the infiltration structure’s maximum design storm runoff volume within 72 hours.

This design permeability rate must be determined by field testing (See Bioretention Pre

Design). Since the actual permeability rate may vary from test results and may also

decrease over time due to soil bed consolidation or the accumulation of sediments

removed from the treated stormwater, a factor of safety of two must be applied to the

tested permeability rate to determine the design permeability rate. Therefore, if the tested

permeability rate of the soils is 4 inches/hour, the design rate would be 2 inches/hour

(i.e., 4 inches per hour/2). This design rate would then be used to compute the structure’s

maximum design storm drain time.

C. Bottom Sand Layer

To help ensure maintenance of the design permeability rate over time, a 6 inch layer of

sand must be placed on the bottom of an infiltration structure. This sand layer can

intercept silt, sediment, and debris that could otherwise clog the top layer of the soil

below the structure. The sand layer will also facilitate silt, sediment, and debris removal

from the structure and can be readily restored following removal operations. The sand

layer must meet the specifications of MDOT Class II sand. This must be certified by a

certified testing lab.

D. Overflows

All infiltration structures must be able to convey overflows to downstream drainage

systems in a safe and stable manner. The capacity of the overflow must be consistent

with the remainder of the site’s drainage system and sufficient to provide safe, stable

discharge of stormwater in the event of an overflow.

E. Subsurface Infiltration Structures

A subsurface infiltration structure is located entirely below the ground surface. It may

consist of a vault, perforated pipe, and/or stone bed. However, due to the greater

difficulty in removing silt, sediment, and debris, all runoff to a subsurface infiltration

structure must be pretreated. This pretreatment must remove 80 percent of the TSS in the

runoff from the structure’s maximum design storm.

Infiltration Structures must be constructed off-line from County Drains.

F. Basis of Design

The design of an infiltration basin is based upon Darcy's Law:

Q = KIA

where:

Q = the rate of infiltration in cubic feet per second (cfs)

K = the hydraulic conductivity of the soil in feet per second (fps)

I = the hydraulic gradient

A = the area of infiltration in square feet (sf)

From the variables shown in the Figure below:

Average Hydraulic Gradient = D

avg

Minimum Hydraulic Gradient = D

Maximum Hydraulic Gradient = D

G. Maintenance

The following requirements must be included in the system’s maintenance plan.

General Maintenance

All infiltration structure components expected to receive and/or trap debris and sediment

must be inspected for clogging and excessive debris and sediment accumulation at least

four times annually as well as after every storm exceeding 1 inch of rainfall. Such

components may include bottoms, riprap or gabion aprons, and inflow points. This

applies to both surface and subsurface infiltration structures. Sediment removal should

take place when the structure is thoroughly dry. Disposal of debris, trash, sediment, and

other waste material should be done at suitable disposal/recycling sites and in compliance

with all applicable local, state, and federal waste regulations.

4.8 Detention Storage Facilities

Detention storage facilities are designed to detain runoff for a short period of time and then

release it to a watercourse where it returns to the hydrologic cycle. The objective of detention

storage is to regulate the released runoff rate and to reduce the impact on downstream drainage

systems. Detention storage should not be confused with retention storage (i.e. retention basins),

a facility with no engineered outlet (other than an emergency-type outlet) designed to hold runoff

for a considerable length of time. The water in a retention basin is not discharged to surface

water, although it may infiltrate in to the ground, evaporate, or be consumed by plants.

In keeping with Common Law Natural Flow Rights and the Michigan Drain Code, concentrated

discharges of stormwater (such as the outflow from a detention facility) or increased surface

water runoff over property owned by others must be pursuant to a valid right-of-way, easement,

or other written permission from all property owners affected. The outflow from a detention

facility is considered to be such a concentrated discharge of stormwater.

All forms of detention storage shall meet the following criteria:

A. On-site detention (or retention – See Section 4.9 Retention Basins) of stormwater is

required of all new developments or redevelopments to maintain the peak outflow to a

rate similar to the pre-development runoff rate. The maximum allowable release rate

shall be 0.15 cfs per acre, but not to exceed the pre-development runoff rate from the 2-yr

/ 24 hr storm event, or a discharge rate approved by the St. Clair County Drain

Commissioner. In no case shall the outflow from a site exceed the capacity of the

receiving watercourse to accept the flow.

B. Detention requirements may be more stringent in certain watersheds according to local

ordinances or policies of the drainage district. In the Crapaud Creek watershed, the peak

allowable discharge rate is limited to 0.1 cfs/acre.

C. The detention basin volume shall be determined for the 100-year flood volume from all

tributary area, including off-site area.

1. The tributary area shall include all acreage contributing runoff to the detention

storage facility, including any off-site tributary area in its existing state, whether

developed or undeveloped.

2. The following equations shall be used to determine the 100-year detention volume:

= Allowable release rate, cfs

= Q

/ (A C), where A = Tributary area in acres, C = weighted runoff coefficient

Detention time in minutes, T = -25 + sqrt(10,312.5 / Q

)

Storage volume per impervious acre, V

= 16,500 T / (T + 25) – 40 Q

Required detention volume in cubic feet, V = V

x A x C

D. If the site is located near the downstream end of a watercourse or drainage district, the

Drain Commissioner may require that the proprietor (or his engineer) generate and

submit hydrographs of the outflow from the existing site and from the proposed site (i.e.

detention facility) and a hydrograph of the flow in the receiving watercourse to verify that

the detained outflow would not result in an increase in the peak flow in the receiving

watercourse. If the detained outflow would result in an increase in the peak flow in the

receiving watercourse, then stormwater detention is not an acceptable stormwater

management option. Retention of stormwater or other stormwater management design

approved by the Drain Commissioner must be provided. See Sections 4.6, 4.7 and 4.9 for

design requirements. The St. Clair County Drain Commissioner’s office may be able to

assist in the determination of the required hydrographs, if needed.

E. All developed areas shall drain to detention basins. However, portions of the developing

site may be allowed to drain unrestricted (i.e. not through a detention facility) if either of

the following conditions are met:

1. The areas draining unrestricted are not being disturbed or altered by the construction,

such that they will maintain their existing drainage characteristics and patterns.

2. The areas draining unrestricted are being disturbed or altered but will be permanently

stabilized to prevent erosion and will not contain any impervious surface post-

construction. In this case, the unrestricted flow must be draining to a receiving

watercourse with valid rights-of-way, or else written agreement from the affected

property owners would have to be obtained per Common Law Natural Flow Rights

and the Michigan Drain Code. In addition, the post-construction peak 100-year flow

from these areas should be calculated and deducted from the total allowable peak

flow from the detention facility (Q

). The detention outlet(s) should be designed to

restrict the basin outflow(s) to this reduced allowable peak flow rate.

F. Where the detention facility is to be equipped with a pump discharge, the St. Clair

County Drain Commissioner may require the proprietor to furnish design data on

pump(s) and discharge force main so that the capacity of the system can be verified.

These data will include system curve calculations, the pump performance curves, and a

profile of the system piping. The pumping station should be able to release the first flush

volume over approximately 24 hours, the bankfull flood volume over 24-48 hours, and

the 100-year flood volume at a rate not to exceed 0.15 cfs/ac of tributary area. A back-up

generator will be required to ensure the operation of the pumping station in the event of

power loss. The Drain Commissioner discourages the use of pumped outlets, and will not

accept responsibility for damages due to power failure, pump malfunction, or Acts of

God that result in storm conditions that exceed the design conditions of the pump station.

G. An agreement for acceptance and maintenance of the detention facility, if executed by the

proprietor, shall be submitted to the St. Clair County Drain Commissioner prior to plat

approval. The agreement both as form and content shall be subject to the approval of the

Drain Commissioner's legal counsel.

H. Under no conditions shall a detention facility be located within the 100-year flood plain

of a stream, creek or lake, as determined by the Drain Commissioner.

I. In-line detention (i.e. detention along the drain) will not be permitted unless it can be

proven beneficial to the drainage district as a whole.

4.8.1 Detention Basins

A detention basin is a form of detention storage where the stormwater is detained above

ground as surface water. An example of a typical detention basin cross section can be found

in Appendix M.

In addition to the general requirements indicated above in Section 4.8, detention basins shall

meet the following requirements:

J. Detention volume in a gravity-outlet detention basin must be located:

1. Above the invert of the lowest row of orifices in the outlet standpipe,

2. Above the elevation of the dry weather base flow in the receiving watercourse,

3. Above the elevation of the groundwater table. Soil boring data used to determine the

groundwater table elevation shall be submitted with the plans.

K. The detention basin outlet shall consist of a vertical standpipe with multi-level orifices.

(See example Standpipe Details in Appendix M.)

1. The standpipe shall not be less than 36 inches in diameter.

2. The standpipe shall contain multiple rows of orifices (i.e. holes) to control the release

of the first flush runoff volume, the bankfull flood volume, and the 100-year flood

volume.

 First flush orifices shall be located at the elevation of the basin floor (or

permanent pool water level, if a wet basin),

 Additional bankfull flood (stream protection) orifices shall be at the elevation of

the first flush volume in the basin, where the first flush volume is calculated as the

first one inch of runoff over the site, or

(cf) = 3630 x A(acres) x C, where C is the runoff coefficient

 Additional 100-year flood control orifices shall be located at the elevation of the

bankfull flood (stream protection) volume in the basin, where the bankfull flood

volume is calculated as the runoff from a 2-year 24-hr storm event (2.30 inches

per NOAA Atlas 14, volume 8, version 2, or

(cf)

= 8349 x A(acres) x C

To promote improved filtering of runoff sediment from smaller, more frequent storm

events, the bankfull flood and first flush volumes shall be based on the developing

tributary site area only, and not include off-site tributary area.

3. Orifices should not be less than 1 inch in diameter or greater than 4 inches in

diameter.

4. The top of the standpipe shall consist of a grating at or above the design (high) water

level to serve as an overflow mechanism, in addition to the overflow spillway/berm.

5. The standpipe shall be encased in stone extending to the design (high) water level to

allow for filtering of the stormwater prior to discharge from the basin. The

encasement stone size shall be large enough so as not to plug or pass through the

orifices in the standpipe.

6. The standpipe shall contain a sediment sump with a depth of at least one foot.

7. Double standpipes (e.g. a 36-inch diameter inner standpipe within a 48-inch diameter

outer standpipe) are encouraged. Double standpipes are believed to be less prone to

blockages of the control orifices, and therefore require less maintenance. The inner

standpipe should contain the appropriate number and configuration of orifices to

provide the controlled release of the first flush volume, the bankfull flood (stream

protection) volume, and the 100-year flood volume. The outer standpipe should

contain at least several times the orifice area as the inner standpipe over the entire

height of the standpipe, such that the head loss across the outer standpipe orifices is

negligible. (See example Double Standpipe Details in Appendix M.)

8. The outlet pipe extending from the standpipe to the receiving watercourse shall be

sized to convey the calculated 10-year peak inflow to the detention basin.

9. The location of the outlet pipe extending downstream of the standpipe shall be

indicated on a profile drawing of the receiving watercourse, whether or not the

receiving watercourse is an established drain. The receiving watercourse profile shall

extend at least from the upstream end of the site to the downstream end of the site.

L. A sediment sump shall be provided within the basin, below the lowest orifice elevation

but above the groundwater table, to provide for sediment accumulation.

1. The volume of the sump shall be equivalent to the first flush volume, or one inch of

runoff over the contributing site area. (Sump Volume, cf = V

= 3630 x A x C)

2. Appropriate precautions shall be taken to protect public safety and to ensure that the

sump does not constitute a nuisance.

M. All detention basins must have standpipe overflow grates and spillways in berms for

emergency overflow at the high water level.

1. The standpipe overflow grate and spillway must provide adequate capacity to

overflow the peak 10-year basin inflow with no more than one foot of head (i.e. water

level must not exceed the one foot of freeboard).

2. Downstream of the overflow spillway, the stormwater overflow must be directed

(either by overland flow or via a swale or ditch) to the receiving watercourse.

N. A minimum of one-foot freeboard shall be provided above the design high water

elevation.

O. The side slopes shall not be steeper than 6 ft. horizontal to 1 ft. vertical unless fenced in

accordance with local township or city requirements. Slope protection shall be provided

as necessary. Basin side slope elevation contours shall be shown on the plans.

P. Unless the detention basin contains a permanent pool, the bottom of all detention basins

shall be graded in such a manner as to provide positive flow to the outlet. A minimum

bottom slope of 1% should be provided.

Q. A 12-ft. wide minimum access easement shall be provided for all detention basins, as

measured from the top of bank.

R. A 25-ft. wide minimum setback from property lines shall be provided for all detention

basins, as measured from the top of bank.

S. Detention basin configurations where stormwater must “back-up” into the basin (i.e.

stormwater enters the conveyance system downstream of the basin) will not be permitted.

T. Multiple detention basins serving a single development should function independently. If

the outflow from one basin passes through another basin before being discharged to the

receiving watercourse, a full hydraulic analysis (i.e. a computer model simulation) will be

required to ensure that the system functions satisfactorily.

U. If at any time the detention basin is to function as a sediment basin (for use during the

construction phase), an outlet filter shall be provided. Such an outlet filter is to be

designed in accordance with criteria established by the St. Clair County Department of

Public Health for Soil Erosion and Sedimentation Control. Such use of a detention pond

shall be considered a temporary measure only. The proprietor shall be responsible for

sediment removal upon completion of construction.

V. Detention basins shall meet all local ordinances and/or requirements for “ponds.”

4.8.2 Underground Storage

Underground storage is a form of detention storage where the stormwater is detained in

underground pipes. Like a detention basin, the water is released at a controlled rate to a

receiving watercourse.

In addition to the general requirements indicated above in Section 4.8, underground detention

facilities shall meet the following requirements:

A. Detention volume in an underground detention facility shall be located above the

elevation of the dry weather baseflow in the receiving watercourse and above the

elevation of the groundwater table. Soil boring data used to determine the groundwater

table shall be submitted with the plans.

B. To minimize sedimentation in the downstream drainage district, sediment shall be

removed from the stormwater before water enters the underground storage facility (e.g. in

first flush forebay or within the catch basins using removable filtration inserts).

C. The pipe material used for the underground storage facility shall have an expected life of

at least 50 years.

D. Access manholes shall be provided along the underground storage facility to allow for

maintenance.

E. A minimum of one foot of freeboard shall be provided between the design hydraulic

grade line in the underground storage facility and the rim elevations of all access

manholes.

F. A 25-ft. wide setback from property lines shall be provided for all underground storage

facilities.

G. An access easement shall be provided to and above the underground storage facility.

H. No permanent structures shall be constructed above the underground storage facility.

4.9 Retention Basins

A “Retention Basin” is a facility with no engineered outlet (other than an emergency-type outlet)

designed to hold runoff for a considerable length of time. The water in a retention basin is not

discharged to a natural watercourse, although it may be consumed by plants, evaporate, or

infiltrate into the ground. A Retention Basin should not be confused with a “Detention Basin,” a

facility designed to detain runoff for a short period of time and then release it to a watercourse.

A. On-site retention (or detention – See section 4.8 Detention Storage Facilities) is required

of all new developments or redevelopments to prevent an increase in peak flows

downstream in the drainage district.

1. Retention basins are an acceptable stormwater management practice on sites where

the soil has an infiltration rate of at least 0.52 inches per hour and a clay content of

less than 30% (per recommendations in Guidebook of Best Management Practices for

Michigan Watersheds). The required storage volume of a retention basin is that of

the runoff from a 100-year design storm as determined using the SCS Method. On

sites with soils having a lower infiltration rate and/or higher clay content (hydrologic

soils groups C or D, for example), the Drain Commissioner may allow retention

basins with storage volume for the runoff from two consecutive 100-year design

storms.

2. Retention basins shall accommodate runoff from off-site areas that drain onto/across

the developing site. (An exception to this rule would be if off-site runoff were to be

routed around the site to a receiving watercourse, if done in a manner such that runoff

from the developing site would not contribute to this off-site flow. If the off-site flow

were to be concentrated from overland flow to a point discharge into a receiving

watercourse without valid rights-of-way, written agreement from the affected

property owners would have to be obtained per Common Law Natural Flow Rights

and the Michigan Drain Code.)

B. One foot of freeboard shall be provided above the design high water elevation.

C. Retention volume must be provided above the elevation of the groundwater table. Soil

boring data used to determine the groundwater table elevation shall be submitted with the

plans.

D. All retention basins must have a spillway for emergency overflow at the high water level.

1. The spillway must provide adequate capacity to overflow the peak 10-year basin

inflow with no more than one foot of head (i.e. water level must not exceed the one

foot of freeboard).

2. The plans must identify where the overflow would be directed to flow or stored in the

event of an overflow.

E. The side slopes shall not be steeper than 6 ft. horizontal to 1 ft. vertical unless fenced in

accordance with local township or city requirements. Slope protection shall be provided

as necessary. Basin side slope elevation contours shall be shown on the plans.

F. A 12-ft. wide access easement shall be provided to and around all retention basins.

G. An agreement for acceptance and maintenance of the retention basin system, if executed

by the proprietor, shall be submitted to the St. Clair County Drain Commissioner prior to

plat approval. The agreement both as form and content shall be subject to the approval of

the Drain Commissioner's legal counsel.

H. If at any time during the construction period the retention basin is to function as a

sediment basin, the proprietor shall be responsible for sediment removal prior to

completion of construction. (See St. Clair County Department of Public Health for

requirements regarding Soil Erosion and Sedimentation Control during construction.)

I. Under no conditions shall a retention basin be located within the flood plain of a stream,

creek or lake.

4.10 Wetlands and Low Lying Areas

A. In order to help in analyzing site hydrology and the pre-development runoff rate, soil

types, the normal groundwater table, and an accurate delineation of wetlands must be

provided as part of preliminary plats/plans. The Drain Commissioner may require

confirmation of the absence or presence of regulated wetlands from the Michigan

Department of Environment, Great Lakes & Energy (EGLE) through its wetland

assessment program. Construction activities to be performed within a regulated wetland

may require a permit from EGLE and/or local municipalities.

B. Any regulated wetlands or other wetlands that will be part of the drainage system shall be

designated as a common area and placed within a conservation easement.

C. If existing wetlands or low lying areas are to be used for stormwater storage, all

requirements under either section 4.8 Detention Basins or section 4.9 Retention Basins

would apply, depending on whether the wetlands/area would have an outlet.

D. If any disturbed or impervious surfaces will drain into an existing wetland or low lying

area, calculations may be required to be submitted indicating that the wetland will

accommodate runoff from a 100-year design storm without exceeding the finished grade

elevation of any adjacent existing or proposed structure.

E. If a wetland will be used for stormwater storage, a sediment forebay shall be provided

upstream of the wetlands to reduce the stormwater velocity and encourage sedimentation.

Additionally, a permit from EGLE and/or local municipalities may be required.

4.11 Oil Separators

Oil must be removed from stormwater as appropriate prior to discharge to a receiving

watercourse. Examples of acceptable Best Management Practices for low oil applications

and for high oil applications can be found in Appendix O. The Drain Commissioner will

consider other means of oil removal on a case-by-case basis.

4.12 First Flush Basins and Sediment Collection Units

Stand-alone, permanent first flush basins and prefabricated sediment collection units are

stormwater Best Management Practices not generally required for developments by the Drain

Commissioner. However, when such BMPs are proposed or required for a specific site, the

following design standards shall apply:

A. A first flush basin or pre-fabricated sediment collection unit shall contain storage volume

for the first one inch of runoff from the on-site impervious tributary area. The storage

volume of a first flush basin can be calculated as:

(cf) = A x C x 3630 cf/ac-impervious

B. The outlet of a first flush basin or sediment collection unit shall be designed to release the

first flush volume over 24-36 hours. This will achieve the goal of 80% sediment removal

or not to exceed 80 mg/L TSS.

C. The outlet of a first flush basin or sediment collection unit shall not be submerged by the

receiving watercourse at a 10-year design level.

D. The first flush basin or sediment collection unit shall contain a bypass structure and/or

berm to allow the 10-year peak flow to bypass without hydraulic interference.

4.13 Design Reference Material

Additional material regarding stormwater design can be obtained from the sources below.

Low Impact Development Manual for Michigan, A Design Guide for Implementers & Reviewers

https://www.semcog.org/Reports/LID/files/assets/basic-html/page-1.html

NOAA ATLAS 14 POINT PRECIPITATION FREQUENCY ESTIMATES: MI

http://hdsc.nws.noaa.gov/hdsc/pfds/

Technical Guidance on Implementing the Stormwater Runoff Requirements for Federal Projects

under Section 438 of the Energy Independence and Security Act, EPA 841-B-09-001

December 2009

https://www.epa.gov/sites/production/files/2015-08/documents/epa_swm_guidance.pdf

Claytor, R. and T. Schueler. December 1996. Design of Stormwater Filtering Systems. The

Center for Watershed Protection. Ellicott City, MD.

Livingston, E.H., H.E. Shaver, J.J. Skupien and R.R. Horner. August 1997. Operation,

Maintenance, & Management of Stormwater Management Systems. In cooperation with U.S.

Environmental Protection Agency. Watershed Management Institute. Crawfordville, FL.

Schueler, Thomas R. and Richard A. Claytor. 2000. Maryland Stormwater Design Manual.

Maryland Department of the Environment. Baltimore, MD.

A-1

APPENDIX A

APPLICATION FOR DRAIN COMMISSIONER REVIEW

A-2

A-3

Application for Drain Commissioner Review

ST. CLAIR COUNTY DRAIN COMMISSIONER

21 Airport Drive, St. Clair, Michigan 48079

The undersigned hereby requests the St. Clair County Drain Commissioner review plans for:

_________________________________________________________________________

Name of project

Please indicate the type of development or construction activity for which plans are being submitted

for review:

 Platted Subdivision (Pursuant to Land Division Act, Act No. 288 of 1967, as amended, M.C.L. §§ 560.101 –

560.293)

___ Pre-preliminary Plat

___ Preliminary Plat

___ Construction Plans

___ Final Plat

Is a Drainage Permit required? _____ Yes _____ No (Check one)

 Condominium Development (Pursuant to Condominium Act, Act No. 59 of 1978, as amended, M.C.L. §§

559.101 – 559.276; the general authority of Drain Commissioners under the Drain Code including Drain Code

Sections 425 and 433; and Local Ordinances)

___ Preliminary Plans

___ Master Deed

___ Construction Plans

Is a Drainage Permit required? _____ Yes _____ No (Check one)

 Private Road or Land Split Development (Pursuant to the general authority of Drain Commissioners under

the Drain Code, including Michigan Drain Code Sections 425 and 433, and Local Ordinances)

___ Preliminary Plans

___ Construction Plans

Is a Drainage Permit required? _____ Yes _____ No (Check one)

 Manufactured Housing Community / Mobile Home Park (Pursuant to Mobile Home Commission Act,

Act No. 96 of 1987, as amended, and the general authority of Drain Commissioners under the Drain Code,

including Drain Code Sections 425 and 433)

___ Preliminary Plans

___ Construction Plans

Is a Drainage Permit required? _____ Yes _____ No (Check one)

 Commercial or Industrial Development (Pursuant to the general authority of Drain Commissioners under

the Drain Code, including Drain Code Sections 425 and 433, and Local Ordinances)

___ Preliminary Plans

___ Construction Plans

Is a Drainage Permit required? _____ Yes _____ No (Check one)

 Direct Discharge to an Established Drain (Pursuant to the general authority of Drain Commissioners

under the Drain Code, including Drain Code Sections 425 and 433, and Local Ordinances)

___ Application for Drainage Permit

A-4

 Drain Widening, Deepening, or Relocation (Pursuant to the general authority of Drain Commissioners

under the Drain Code, including Drain Code Sections 425 and 433, and Local Ordinances)

___ Application for Drainage Permit

 Drain Crossings, Culverts, Tiling, and/or Enclosing an Established Drain (Pursuant to the general

authority of Drain Commissioners under the Drain Code, including Drain Code Sections 425 and 433, and Local

Ordinances)

___ Application for Drainage Permit

 Adding or Subtracting Land to/from a Drainage District and/or Construction of a Drain for

Ascription as an Established Drain (Pursuant to the general authority of Drain Commissioners under the

Drain Code, including Drain Code Sections 425 and 433, and Local Ordinances)

___ Draft Section 433 Agreement

Attached are initial review fees in the amount of: ____________

(See Review & Permit Fees Schedule)

I hereby grant permission to the Drain Commissioner, his employees, agents, or consultants, to enter and

inspect the site under review. I am the owner of the property or the owner’s agent and am authorized to

grant this permission. I also understand and agree that I am obligated to and will reimburse the St. Clair

County Drain Commissioner for all out-of-pocket consulting, engineering, site inspection,

administration, and/or legal expenses incurred by the Commissioner in connection with review of this

site and plans.

______________________________________________________ ___________________________

Signature Date

______________________________________________________ ___________________________

Name printed Date

Send copies of reviews to:

_______________________________________ _ ________________________________________

Name Name

________________________________________ ________________________________________

Address Address

________________________________________ ________________________________________

B-1

APPENDIX B

REVIEW & PERMIT FEES

B-2

B-3

ST. CLAIR COUNTY DRAIN COMMISSIONER

REVIEW & PERMIT FEES

Initial Fees Due with Application

Pre-preliminary Plat Review $ 100

Preliminary Plat or Site Plan Review $ 550

Construction Plan Review (Stormwater Facilities) $ 600

Plus $10 for each residential lot, or

Plus $50/acre for commercial sites

Final Plat Inspection and Review: $ 200

Re-submittal Review Fees: 50% of Initial Fees

Drainage Permit–Development/Construction Activities, $250

Direct Discharge, Widening/Deepening/

Relocation

Drainage Permit–Residential, Agricultural, Utility Crossing, $175

Culverts, Tiling, Enclosing

Inspection Fees: $ 50/hour

In addition to these fees, there may also be additional costs if the project requires the relocation, clean-

out, tiling, extension or establishment of a county drain, pursuant to Sections 425 or 433 of the Michigan

Drain Code.

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C-1

APPENDIX C

DRAINAGE APPLICATION AND PERMIT FORM

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St. Clair County Drain Commissioner Permit No.: ______________

21 Airport Drive

St. Clair, Michigan 48079 Fee Deposit: _____________

Phone: (810) 364-5369

Fax: (810) 364-7240

DRAINAGE PERMIT

Application and Permit Authorizing Development

or Construction Activities Affecting Drainage Pursuant to Section 2.0

Of the Rules of the St. Clair County Drain Commissioner

Pursuant to applicable provisions of the Rules of the St. Clair County Drain Commissioner and

the Michigan Drain Code, Public Act No. 40 of 1956, as amended, the undersigned landowner(s)

has petitioned the Drain Commissioner (or Drainage Board) for permission to undertake

development or construction activities which will affect drainage conditions or drainage patterns

within a legally established Drainage District, which would require additional drainage to an

established Drain, or which would potentially increase contaminant levels within an established

Drain. Such activities include, but are not limited to, tapping into, adding new or additional

discharges to, or changing the magnitude, concentration, or frequency of runoff discharges to any

established Drain, creek, river, ditch, or other natural watercourse in St. Clair County.

This permit is granted for _________________________________________________________

__________________________________________________________________ in accordance

with the plans labeled____________________________________________________________

______________________________ and dated _____________________________, which have

been approved by the Drain Commissioner and are hereby made a part of this permit. All

underground lines must be buried a minimum of 5 feet below the bottom and side slopes of the

drain unless a written agreement is reached between both parties stating otherwise.

The permitted activity will affect drainage to ______________________________________

(drain or watercourse) as part of the _____________________________________ Drainage

District. The proposed drain is located in the municipality(s) of _________________________.

1. The undersigned landowner(s), their heirs and assigns, agree to construct and maintain the

stormwater facilities so that they function as designed in the approved plans and as approved by

the Drain Commissioner or Drainage Board on behalf of the Drainage District.

2. The landowner(s) certify that consent in writing has been obtained from all owners of land to

be traversed by the proposed drain, and that they have supplied the Drain Commissioner with

true copies of that consent.

3. The undersigned contractor agrees to perform construction in a good workman-like manner

according to the approved plans and specifications. The county or inter-county drain shall be

restored to the same or better condition as existed prior to construction. Drainage shall be

maintained and left unobstructed during construction so as to prevent backing up of water which

could cause flooding of other lands.

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4. The undersigned contractor agrees to notify the Drain Commissioner at least 48 hours prior to

the beginning of the construction performed under this permit so that the Drain Commissioner

may have an inspector present during construction.

5. The landowner(s) or contractor agree to pay all costs to the Drain Commissioner for review of

the plans and issuance of permit, including engineering fees, legal fees, and inspection fees.

Inspection fees will be charged at the rate of ________ per hour. An estimate for fees and costs,

based on the complexity of the project, shall be deposited with the Drain Commissioner in the

amount noted at the top of this form. This deposit is non-refundable if the contractor fails to give

notice prior to construction as required above.

6. The landowner(s) and contractor agree to repair any damage they might cause to the county or

inter-county drain as a result of this construction. The Drainage District, Drainage Board, Drain

Commissioner and St. Clair County shall be kept free and harmless by the landowner and

contractor from all loss, cost, or damage sustained by any person or property as a result of

operations performed under this permit.

7. This permit does not relieve the landowner(s) or contractor of responsibility to secure any

additional local, state, or federal permits required and to meet any other permit requirements of

law or other public bodies or agencies.

8. This permit is subject to additional terms and conditions as

follows:_______________________________________________________________________

______________________________________________________________________________

Signed by:

_____________________________________ ____________________________________

Landowner or authorized agent signature Contractor signature

_________________________________________________ ________________________________________________

Name printed Name printed

_________________________________________________ ________________________________________________

Address Address

_________________________________________________ ________________________________________________

City City

_________________________________________________ ________________________________________________

Phone number Phone number

_________________________________________________ ________________________________________________

Date Date

Permit Issued by St. Clair County Drain Commissioner on: _____________

_________________________________________________

Signature

_________________________________________________

Title

D-1

APPENDIX D

SECTION 433 AGREEMENT APPLICATION:

APPLICATION TO ADD/SUBTRACT LAND TO/FROM A DRAINAGE DISTRICT

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D-3

AGREEMENT TO ADD LANDS TO THE DRAINAGE DISTRICT PURSUANT TO

SECTION 433 OF THE MICHIGAN DRAIN CODE

__________________ Drain Drainage District, St. Clair County

This instrument made and entered into this ____ day of ______________, _______, by

and between Bob Wiley, St. Clair County Drain Commissioner (herein “Drain Commissioner”),

2 Airport Drive, St. Clair, Michigan 48079, acting for and on behalf of the _____________

Drain Drainage District, a public body corporate (hereinafter “Drainage District”) and

__________________________, of ___________________________, landowners and

developers, (herein “Developer”).

WITNESSETH:

WHEREAS, the Drainage District, pursuant to the Michigan Drain Code (Act 40 of the

Public Acts of 1956, as amended), is an established body corporate under the jurisdiction of the

Drain Commissioner, in the County of St. Clair and State of Michigan;

WHEREAS, the Developer, pursuant to Section 433 of the Michigan Drain Code wishes

to add lands to the Drainage District as part of the _______________________________;

WHEREAS, those lands are described as follows:

(See Exhibits ___________ attached)

WHEREAS, stormwater drainage facilities have been constructed to service those lands

as part of the _________________________________;

WHEREAS, pursuant to Section 433, the Developer has obtained at his/her own expense

a certificate from a registered professional engineer satisfactory to the first party, to the effect

that the lands to be added naturally drain into the area served by the existing drain or that the

existing drain is the only reasonably available outlet for the drainage from the lands to be added

and that there is existing capacity in the existing drain to serve the lands to be added without

detriment to or diminution of the drainage service provided or to be provided, in the foreseeable

future, to the area in the existing drainage district.

NOW, THEREFORE, the parties agree as follows:

1. The lands described above shall be added to the drainage district and shall be

from this date forward liable for their apportioned share of maintenance,

inspection and repair assessments for the __________ Drain as well as

assessments on any county or intercounty drain providing outlet benefits to the

added lands.

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2. The Developer shall pay or has paid the cost of the drainage facilities and the cost

of engineering, inspection, administration, and legal expenses incurred by the

drain commissioner, pursuant to Section 433.

3. This Agreement shall become effective upon its execution by the parties and shall

be binding upon the successors and assigns of each party.

IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed

by their duly authorized officers.

Witnessed:

______________________________ ______________________________

By:

______________________________ Its:

Subscribed and sworn to before me this

_____ day of _______________, _______.

_______________________________

Notary Public, St. Clair County, MI

Acting in St. Clair County, Michigan

My commission expires:

_____________ Drainage District

Witnessed: Drain Commissioner

______________________________ ______________________________

By: Bob Wiley, St. Clair County

Drain Commissioner

______________________________

Subscribed and sworn to before me this

_____ day of _______________, ________.

_______________________________

Notary Public, St. Clair County, MI

Acting in St. Clair County, Michigan

My commission expires:

Drafted by and return to: Bob Wiley

St. Clair County Drain Commissioner

21 Airport Drive

St. Clair, MI 48079

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APPENDIX E

EXAMPLE PERMIT STATUS TABLE

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Example Permit Status Table

Permit Agency Reason for Permit Application

Date

Date Issued

Soil Erosion Control

Permit

SCC Dept. of

Public

Health

Soil to be disturbed during construction activities 4/10/18 5/5/18

Road Commission Permit

SCC Road

Commission

Public roads proposed 4/15/18 5/10/18

Inland Lakes and

Streams Permit

EGLE/Army Corp. Proposed culvert has more than 2 square miles

tributary area

5/25/18 6/15/18

Wetlands Permit EGLE/Army Corp. Construction of parking lot will disturb existing

wetlands

5/25/18 6/15/18

Drainage Permit SCC Drain

Commissioner

Proposed discharge of flow to established drain 4/20/18

Drainage Permit SCC Drain

Commissioner

Proposed culvert crossing on established drain 4/20/18

NPDES Phase II Permit EGLE More than 1 acre to be disturbed during

construction

4/15/18

MDOT Permit MDOT Proposed driveway construction in MDOT

R.O.W.

4/30/18

E-4

F-1

APPENDIX F

PRELIMINARY PLAT/PLAN CHECKLIST

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F-3

DEVELOPMENT NAME: DATE:

LOCATION: REVIEWED BY:

ENGINEER’S EMAIL ADDRESS:

CHECKLIST FOR PRELIMINARY PLATS/PLANS

Page No.

Approved

Plat Name

(e.g. Preliminary Plat of “Residential Hills”

________

2. Description of Location (Including Section and fractional

portion thereof, Town and Range designation, Township

or City of St. Clair County, Michigan)

________ ________

Location Map

________

Name, Address and Telephone No. of proprietor

________

Name,

Address and Telephone No. of Engineer/Surveyor

________

Scale not smaller than 1”=100’

________

Engineer’s Seal, all sheets

________

Tentative approval of Governing Body

________

North Arrow and

Scale

________

10.

Bar Scale

________

11.

USGS Benchmark Description

________

12.

Legend

________

13. Typical Road cross-section (Label road as “Public Road”

or “Private Road”)

________ ________

14.

Lot

Square Footage (Minimum)

________

15.

Proposed Improvements

________

16.

Plat Boundary

________

17. Identification of all adjoining parcels (For subdivisions

show Lot Number, Subdivision Name, Liber & Page

Numbers. For acreage parcels, show Tax roll number &

proprietor name.)

________ ________

The following information shall be included on all Preliminary Plats and Plans submitted for

approval by the St. Clair County Drain Commissioner.

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Page No.

Approved

18. Existing Buildings (Label those under construction with

address)

________ ________

19. Existing Roads (w/Name, R.O.W. width and width and

type of

surface.)

________ ________

20.

Proposed Roads (with Names and R.O.W. widths)

________

21. Property Description Metes & Bounds (w/Ties to

government corner.)

________ ________

22.

Lot Dimensions

________

23.

Lot Numbers

________

24.

Building Setback Lines

________

25.

Typical Lot Grading Plan Detail or Statement

________

26.

Minimum House Grade for Each Lot

________

27.

Basement Elevations for Each Lot

________

28. Soil Boring Logs and Locations (to include ground

elevation at each boring log and water table information.)

Logs from site report prepared for Dept of Health are

acceptable.

________ ________

29.

Existing Contours

________

30. Easements (w/dimensions, utility and existing drain

easements.)

________ ________

31. Identification of entity to assume ownership of drainage

system (including detention facilities)

________ ________

32. Off-site watershed areas and/or drainage district

(w/boundaries and acreages to be shown on Location Map)

________ ________

33. All existing drainage courses and structures (w/proper

labeling as to type, size, and invert elevations.)

________ ________

34.

Flood Plain Contour (Existing or

Proposed)

________

35. Boundaries and acreages of tributary areas of all proposed

and existing inlets, catch basins and culverts.

________ ________

36. Proposed drainage system (Clearly identify all open and

enclosed portions.)

________ ________

37.

Proposed Drainage Easements

________

38.

Intercepting Swales

–

Easements

________

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Page No.

Approved

39.

Established Drains (permit required to tap)

________

40.

Off

site Drain Easements/ ROWs

________

41. If established drain involved, note that “All work… in

accordance with… Rules.”

________ ________

42.

Wetlands delineated

________

43.

Floodplains

________

44.

Proposed stormwater detention/retention basins

________

45.

Receiving watercourse(s) identified

________

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G-1

APPENDIX G

CONSTRUCTION PLAN CHECKLIST

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G-3

DEVELOPMENT NAME: DATE:

LOCATION: REVIEWED BY:

ENGINEER’S EMAIL ADDRESS:

CHECKLIST FOR CONSTRUCTION PLANS

Page No.

Approved

General Requirements

1. Approved Preliminary Plat included OR plans also

conform to Preliminary Plat Checklist (submit

Preliminary Plat Checklist)

________ ________

2. Agreement re: maintenance of stormwater

management facilities (including existing

watercourses)

________ ________

3. O&M Agreement recorded with Register of Deeds

and Liber

Page provided

________ ________

Drainage systems for prior phases shown

________

5. Grading Plan with existing and proposed contour

lines shown

________ ________

6. Proposed minimum finish floor or finish basement

elevations

________ ________

7. Existing watercourses shown and preserved,

relocated or accommodated

________ ________

No construction activities in floodplain

________

Permit Status Table shown

________

10. Note: “All work performed in the right-of-way of

an established drain shall be in accordance with

Drain Commissioner’s Rules.”

________ ________

11.

Engineer’s seal on all sheets

________

Established Drains

12. Plans and profiles of established drains in road or

drain easements shown, including base flow profile

and basin outlets

________ ________

13. Min. open drain easement 40’ plus top width, 20’

top of bank to easement

________ ________

The following information shall be included on/with all Construction Plans submitted for

approval by the St. Clair County Drain Commissioner.

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Page No.

Approved

14.

Min. 20’ easement for enclosed drains

________

15.

Drains used as outlet improved if necessary

______

________

16.

Outlet to Drain enters at 90 degrees max.

________

17.

Drain easement cut/fill volume table

________

18. Drain re-stabilization in accordance with SESC

APA Manual

________ ________

Storm Sewers

19. Delineated catchment areas for each catch

basin/inlet

________ ________

20. Off-site tributary area included in design, or

rerouted

________ ________

Storm sewers designed per Rational Method

________

22.

Storm sewers designed for 10

year peak flow

________

23. Storm sewers designed using standard intensity

equation

________ ________

24.

Storm sewer design runoff coefficient reasonable

________

25.

Sewer capacities based on Manning equation

________

26. Friction losses based on design flows, not pipe

capacities

________ ________

27.

Sewers designed using appropriate Manning n

________

28.

Manhole losses included

________

29.

Storm sewer capacities meet/exceed design flows

________

30.

Min. 12” pipe diameter

________

31.

Sewer slopes meet/exceed minimum slopes

________

32. Storm sewer design velocities acceptable (2.5 < V <

10 fps)

________ ________

33.

Hydraulic grade line shown on storm sewer profile

________

34. Hydraulic grade line 1 foot min. below rim

elevations

________ ________

35. Hydraulic grade line assumes receiving water

elevation (e.g. full detention basin)

________ ________

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Page No.

Approved

36.

Manholes and CBs labeled

________

37. Sewer lengths, diameters, slopes, pipe class, trench

details identified

________ ________

38. Manholes spacing 400 ft max for sewers < 30”

(600 ft for larger sewers)

________ ________

39. Drainage structure dia. 48” min, inlet dia. 24” min,

inlet depth 3.5’ to 5’

________ ________

40. Drainage structures brick, block, precast or cast-in-

place

________ ________

41. CB/inlet spacing in street R.O.W. 400 ft. max. or

for 1 cfs max.

________ ________

42. Pipe, manholes, catch basins, inlets meet MDOT

specs

________ ________

43.

No manhole drops over 2 feet

________

44.

Joints pointed up with mortar for pipes over 30

inch

________

45.

Outlets enter receiving watercourse at <90 degrees

________

46.

Storm sewer easements

shown, min. 40 ft width

________

47.

Existing & proposed drainage easements shown

________

48. Utilities in drain easements not in conflict with

sewers

________ ________

Open Channels

49.

Open channels designed per Rational

Method

________

50.

Open channel design runoff coefficient reasonable

________

51. Open channels designed using standard intensity

eqn

________ ________

52.

Open channels 10

year peak flow is within banks

________

53. Open channel capacities based on Manning

equation

________ ________

54. Open channel designed using appropriate Manning

________ ________

55. Open channel velocities acceptable (1.5 < V < 5

fps)

________ ________

G-6

Page No.

Approved

56. Open channels in easements, 40 ft + top width, 20’

top of bank to easement

________ ________

57.

Open channel side slopes not steeper than 3:1

________

Culverts

58. Culverts labeled “existing” “proposed” or “to be

extended”

________ ________

59.

Culvert design flow calculated w/ correct method

________

60.

Inlet and outlet control nomographs/equations used

________

61. Culvert 10-yr headwater is 1 ft min. below

road

way

/driveway

________ ________

62.

Culvert 100

headwater does not flood structures

________

63.

Reasonable tailwater used

________

64. Culvert end sections / head-walls / wing walls

acceptable

________ ________

65.

Culvert data provided

________

66.

Culvert

riprap acceptable

________

67.

Culverts 18” minimum dia.

________

Culverts meet MDOT specs

________

Bioretention

69.

Soils and site are suitable for Bioretention

________

70.

Bioretention designed for

year, 24 hour storm

________

71. Bioretention water depth 12” max. in swales, 18”

max. in structures

________ ________

72.

Bioretention outlet/overflow orifice 2.5” min.

________

73. Bioretention 2’ min. above seasonal high water

table

________ ________

74. Bioretention drains water quality storm within 72

hrs

________ ________

75.

Planting bed permeability safety factor of 2 applied

________

76.

Planting soil bed acceptable

________

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Page No.

Approved

77.

Bioretention Vegetation acceptable

________

78.

Bioretention sand layer 12” min.

________

79.

Bioretention underdrain is rigid Schedule. 40 PVC

________

80.

Bioretention has sufficient overflow capacity

________

81.

Tailwater elev. in receiving stream is considered

________

82.

Bioretention is off

line from County Drain

________

Infiltration

83.

Soils and site are suitable for Infiltration

________

84.

Infiltration designed for maximum design storm

________

85.

Infiltration fully drains within 72 hrs

________

86. Infiltration structure 2’ min. above seasonal high

water table

________ ________

87.

Surface infiltration water

depth = 2’ max.

________

88. Infiltration structure subgrade compaction is

avoided

________ ________

89.

Infiltration permeability safety factor of 2 applied

________

90.

6” sand layer included

________

91. Infiltration structure has sufficient overflow

capacity

________ ________

92.

Subsurface infiltration systems include pretreatment

________

93. Infiltration structures are off-line from County

Drain

________ ________

94.

Infiltration

design based on Darcy’s Law

________

Detention

95.

Detention discharges to valid right

way

________

96.

Detention max outflow <0.15 cfs/ac

________

97.

Detention volume designed for 100

year storm

________

98.

Off

site acreage included in detention volume calc

________

G-8

Page No.

Approved

99.

Appropriate sizing eqns used

________

100.

Detention will not increase downstream peak flow

________

101. Areas draining unrestricted are undisturbed or

contain only pervious surface

________ ________

102. Concentrated discharge to valid R.O.W. – or --

agreement with downstream property owners

________ ________

103. Disturbed areas draining unrestricted were deducted

from basin outlet design

________ ________

104. If pumped outlet, system curve, pump curves,

profile submitted

________ ________

105. If pumped outlet, discharges first flush over 24

hours, bankfull flood over 24-48 hours, and 100-

year

storm at <0.15 cfs/ac

________ ________

106.

Drainage system / basin maintenance agreement

________

107.

Detention is not within 100

year floodplain

________

108.

Detention is not “in

line”

________

109. Storage volume provided above orifices, receiving

watercourse baseflow, and groundwater table

________ ________

110.

Standpipe outlet

with multilevel orifices

proposed

________

111.

Standpipe at least 36” dia.

________

112. Basin outlet is multi-stage for first flush, bankfull

flood, and 100

year storm

________ ________

113. Bankfull flood and first flush volumes do not

include off

site tributary area

________ ________

114.

Orifice size 1” min., 4” max.

________

115.

Standpipe has overflow grate at high water level

________

116.

Standpipe encased in stone to high water elevation

________

117.

Standpipe has sediment sump, 1’ min. depth

________

118. If double standpipe used, outer pipe orifices

adequate

________ ________

119. Outlet pipe from standpipe sized for 10-year peak

flow

________ ________

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Page No.

Approved

120. Profile of outlet pipe and receiving watercourse

shown

________ ________

121. Detention basin sediment sump sized for first flush

vol.

________ ________

122. Standpipe overflow grate and emergency spillway

in berm have combined capacity for 10

yr flow

________ ________

123. Emergency spillway overflow directed to receiving

watercourse

________ ________

124.

Basin has 1’ min. freeboard

________

125.

Basin side slopes 6:1 or flatter, unless fenced

________

126. Detention basin bottom slope 1% min. or permanent

pool

________ ________

127.

ft access

easement to and around detention basin

________

128.

ft setback from property lines to basin

________

129.

Basin is not “back

up” configuration

________

130.

Multiple detention basins function independently

________

131. If detention basin used as sediment basin, outlet

filter provided

________ ________

Underground Storage

132.

Soil boring data submitted for underground storage

________

133.

Sediment removed before underground storage

________

134.

Underground storage pipe material has 50

year life

________

135.

Access manholes provided for underground storage

________

136.

Underground storage facility has 1’ freeboard

________

137. 25-ft setback from property lines to underground

storage

________ ________

138.

Access easement to and above underground storage

________

139.

No permanent structures above underground storage

________

G-10

Retention

Page No.

Approved

140. Soil infiltration rate for retention > 0.52 in/hr, clay

content < 30%

________ ________

141. Retention basin designed for runoff from 100-year

storm

________ ________

142. Off-site tributary area included in design, or

rerouted

________ ________

143. Rerouted off-site drainage to valid R.O.W. – or --

agreement with downstream property owners

________ ________

144.

Basin has 1’ min. freeboard

________

145. Retention above groundwater table, soil borings

submitted

________ ________

146. Emergency spillway in berm has capacity for 10-yr

flow

________ ________

147.

Emergency spillway overflow route shown

________

148.

Basin side slopes 6:1 or flatter, unless fenced

________

149.

access easement to and around retention basin

________

150.

Retention basin maintenance agreement submitted

________

151. If retention basin used as sediment basin, outlet

filter provided

________ ________

152.

Retention is not

within 100

year floodplain

________

Wetlands

153.

Wetlands delineated, in conservation easement

________

154. Drainage into wetland will not raise water surface

above structures

________ ________

155. If wetlands to serve as detention/retention, sediment

forebay provided

________ ________

Oil Separators

156.

Oil removal BMP’s shown (where required)

________

157.

Oil/grit separators meet design standards

________

G-11

First Flush Basins/Sediment Collection Units

Page No.

Approved

158. First flush basin or sediment collector (FFB/SC) has

storage volume for 1” of runoff

________ ________

159.

FFB/SC release time between 24

36 hours

________

160. FFB/SC outlet not submerged by receiving

watercourse at 10

year design level

________ ________

FFB/SC bypasses 10

year peak flow

________

G-12

H-1

APPENDIX H

MODEL FORMS OF STORMWATER SYSTEM MAINTENANCE AGREEMENTS

H-2

H-3

DECLARATION OF DRAINAGE EASEMENT

AND DRAINAGE MAINTENANCE AGREEMENT

This declaration made this ________ day of _______________, 20__, by

_______________, whose address is ___________________________________________

(hereinafter “Developer”), and on behalf of

_____________________________________________, a Homeowner’s Association to be

formed (hereinafter “Association”).

WHEREAS, the Developer is the owner of all legal and equitable interest in the following

property located in the Township of _______________, County of St. Clair, State of Michigan,

(hereinafter “Development”) described as:

See legal description attached hereto as Exhibit 1.

WHEREAS, the Developer has divided the Development, known as

_______________________________ into Lots for the purpose of residential home sites;

WHEREAS, Developer is constructing a public road on the Development for the purpose of

providing ingress and egress to the Lots and is also providing drainage for the Lots;

WHEREAS, the purpose of this declaration is to provide for the development and maintenance

of easements and other drainage facilities to provide proper drainage for the Development;

NOW THEREFORE, in consideration of the mutual benefits to be derived by the Developer, its

successors and assigns, and all purchasers and future owners of the various Lots comprising the

Development, the Developer, for itself, its successors and assigns, does hereby publish, declare

and make known to all intending purchasers and future Owners of the Lots comprising the

Development, that all Lots in the Development will and shall be used, owned, held and/or sold

expressly subject to the following covenants, conditions, restrictions, easements, obligations and

special assessments for the development and maintenance of Drainage Easements and Facilities

as described in this Agreement.

It is further declared that the Drainage Easements and Facilities described in Exhibit __________

attached hereto, together with the drainage maintenance provisions contained herein shall run

with the land and be binding on the Developer and purchasers of all Lots in the Development and

their heirs, personal representatives, successors and assigns.

1. DEFINITION OF TERMS. The words and phrases following used in this

Agreement are defined as follows:

a. “Agreement” shall mean and refer to this Declaration of Drainage Easement and

Drainage Maintenance Agreement as recorded in the Office of the St. Clair County

H-4

b. “Association” shall mean and refer to Homeowners’

Association and its successors and assigns;

c. “Developer” shall mean and refer to and its

successors and assigns;

d. “Drain Commissioner” shall mean the St. Clair County Drain Commissioner;

e. “Drainage Easements and Facilities” shall mean those areas of land within the

Development (including the improvements thereto) now or hereafter owned by the

Association or used by the Association or Owners for the drainage purposes as

referenced in this Agreement;

f. “Lot” shall mean and refer to any Lot or parcel of land within the Development;

g. “Member” shall mean and refer to those persons entitled to membership in the

Association, as provided in this Agreement;

h. “Owner” shall mean and refer to the record owners, whether one or more persons or

entities, of the fee simple title to any Lot which is a part of the Development. When

more than one person or entity has an interest in the fee simple title to a Lot, the

collective interest of all such persons or entities shall be considered to be that of a

single Owner for purposes of this Agreement. If any Lot is sold on a land contract,

the land contract purchaser shall be considered the Owner. Those persons having any

interest in a Lot merely as security for the performance of an obligation are not

considered to be Owners.

2. DRAINAGE EASEMENTS AND FACILITIES. The Drainage Easements and

Facilities subject to this Agreement are shown and described in Exhibit ___________, attached

hereto. Each purchaser of the Lots in the Development acquires an indivisible property interest

to all the above-described Drainage Easements and Facilities for the purpose of constructing,

operating, inspecting, maintaining and repairing such Facilities. The financial responsibility for

maintenance of the Drainage Easements and Facilities shall be the Association’s and be shared

by the Owners of all of the Lots in the Development pursuant to the terms of this Agreement,

except that minor maintenance of the drainage areas (such as mowing and landscaping along and

around the Drainage Easement and Facilities) shall be performed by the Owners of the Lots

where the Drainage Easements and Facilities are located. All Owners are deemed to have

consented to entry upon their property necessary to construct, inspect and maintain the Drainage

Easements and Drainage Facilities. No buildings or permanent structures may be constructed or

maintained over or on any easement area subject to this Agreement. This Agreement shall be

perpetual and terminable only upon the occurrence of any one of the following events:

(1) The Drainage Easements and Facilities are no longer necessary to service the

Development and are abandoned or replaced with the express written permission

of the Association and the Drain Commissioner; or

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(2) A Municipality or a Governmental Agency with taxing powers expressly

assumes, in writing, the responsibility for the operation and maintenance of the

Drainage Easements and Facilities; or

(3) A county or intercounty drainage district is established to operate and maintain

the facilities and easements in accordance with Act 40 of the Public Acts of 1956,

as amended, and the Rules of the St. Clair County Drain Commissioner.

3. HOMEOWNERS ASSOCIATION. There is hereby created an Association, which

consists of all the Owners of Lots located within the Development and shall be known as the

_________________________ Homeowner’s Association. Membership in the Association is

mandatory for each Owner. The Owners of each Lot shall have one (1) vote in the Association

(i.e., one vote per Lot, regardless of the number of Owners of the Lot). The Association shall

annually elect a president, secretary, and treasurer, which together shall constitute the Board of

Directors of the Association (hereafter “the Board”). In the event that such officers are not

elected, the existing officers may serve until the new elections take place. In the event that an

officer dies, resigns, or is unable or unwilling to carry out his/her duties during the year, the

remaining offices may appoint a replacement who shall serve until a new officer is elected. The

presence of two (2) members of the Board at a meeting shall constitute a quorum. If only two (2)

members of the Board are present at a meeting, the affirmative vote of both is required to take

action. Upon majority vote of the Owners of all of the lots in the Development (one vote per

lot), the Association may choose to convert the Association to a non-profit corporation or limited

liability company which shall carry out the same functions as the Association.

a. ASSOCIATION MEETINGS. Each year, during the first week of

____________________ (or such other date as a majority of the Association

member shall designate), the Association members shall meet for the purpose

of electing a Board of Directors (the “Board”) and officers and approving a

maintenance program and budge for the coming year for the Drainage

Easements and Facilities. An Owner may vote in person or by proxy

authorized in writing signed by the lot Owners (or one of them). For purposes

of the annual meeting and setting of the budget, it is not necessary that a

majority of Owners be present in person or by proxy in order that a valid

meeting is held. Owners or proxies representing at least fifty percent (50%) of

the Lots in the Development shall constitute a quorum. Questions shall be

approved or disapproved by a majority of Owners present in person or by

proxy and voting at the annual meeting or any special meeting called for

purposes of this Agreement. Written notice of the time and location of the

annual meetings shall be provided to all Owners of record in the

Development.

Special meetings may be called with ten (10) days prior written notice to all

Owners by the President of the Board or upon request of any three (3)

Owners representing (3) separate Lots.

Until such time as all of the Lots in the Development have been sold, by the

Developer, or sooner if the Developer so chooses, the Developer shall

exercise all the powers and duties of the Association and its Board. However,

H-6

all Owners are entitled to attend the annual meeting and give input into the

setting of the forthcoming budget. The Developer may from time to time

designate an agent for the purpose of maintaining and enforcing the

Agreement. Appropriate written notice of such designation, or any other

written notice permitted or required by this Agreement, shall be addressed by

ordinary mail to each Owner.

The Developer may at any time assign and convey all or part of his rights,

powers, privileges and duties, which are reserved to it in this Agreement, to

the Association, and upon the execution and filing of the appropriate

instruments of assignment, the Association shall thereupon have the right and

obligation to exercise all the rights, powers, privileges and duties so assigned

by this document to the Developer.

b. DUTIES: GENERALLY. The purpose of the Homeowners Association is to

manage the Drainage Easements and Facilities in the Development and

matters incidental thereto for the benefit of all owners and to enforce these

restrictions and any by-laws, rules or regulations the Association may adopt.

Adoption of by-laws, rules or regulations shall require the affirmative vote of

those owning a majority of the lots in the Development at an annual meeting

or a special meeting called for that purpose.

c. BUDGET. The Board shall be responsible for drafting a proposed budget for

maintenance and repair of Drainage Easements and Facilities for the coming

year, if any.

d. MAINTENANCE AND REPAIR WORK. The President of the Board shall

arrange for such maintenance and repair work as has been approved by the

Association. All bills for approved work shall be paid by the treasurer after

approval by the officer designated for this purpose by the officers. The budget

may include a reserve for future capital expenditures. The Board may

authorize above-budget expenditures for emergency maintenance and repairs

where the failure to do so would result in a threat to health, human safety, or a

risk of financial loss to the Association.

e. ASSESSMENT. Each landowner shall pay an annual assessment for the

maintenance program required pursuant to Paragraph 3, Subparagraph d. of

this Agreement.

f. ASSESSMENT COLLECTION. All assessment payments shall be made

payable to the Association. Payment is due thirty (30) days after the

assessment is mailed by first class ordinary mail. The treasurer shall place all

funds collected in the Association account at a federally insured banking

institution selected periodically by the Board.

g. FAILURE TO PAY ASSESSMENT. If any Owner is in default for any

assessment payment of thirty (30) or more days, the Association may bring

suit to collect the assessment, together with any costs of collection including

H-7

reasonable attorney fees. Additionally, the Association may file a lien against

the land in the public records and foreclose the lien in the same manner as the

enforcement and foreclosure of mortgages in Michigan. For any Lot in the

Development whose dues remain unpaid more than four (4) months after the

dues notices are mailed, the delinquent Lot owner shall lose their right to vote

as a member of the Association and as a member of the Board until such time

as the delinquent dues are paid.

h. REMEDIES. By acceptance of title, Owner vests in the Association and/or

the Drain Commissioner the right and power to take any legal action which it

may deem necessary or advisable to enforce this Agreement or any of its rules

or regulations. Upon violation of any restriction or breach of any covenant,

the Association and/or the Drain Commissioner may enforce it by a suit for

money judgment, by foreclosing of the lien securing payment, or by an action

in equity seeking a mandatory injunction. If an Owner is found to be in

violation of any of these restrictions, covenants, or any duly adopted rules or

regulations of the Associations, the violator agrees to pay the reasonable

attorney fees and other costs incurred by the Association and/or the St. Clair

County Drain Commissioner in such enforcement action and authorizes the

court to enter an order requiring such payment.

In addition to all other remedies, the Association and/or Drain Commissioner

may enter upon any land in the Development for purposes of carrying out the

provisions of this Agreement and neither the Association nor the Drain

Commissioner shall be liable for trespass and shall further be held harmless

for any damage or liability occurred thereon as a result of enforcing this

Agreement.

The St. Clair County Drain Commissioner shall have the right, but not the

obligation, to enforce all provisions of this Agreement and to require

appropriate maintenance of and/or improvements to the Drainage Easements

and Drainage Facilities referenced in this Agreement if the Developer or the

Association fails to adequately maintain the Drainage Easements and

Facilities. All costs incurred by the Drain Commissioner, including but not

limited to engineering and attorney fees, shall be paid by the Developer,

Owners or Association as otherwise provided in this Agreement. Failure of

the Drain Commissioner to enforce any covenant or restriction herein

contained shall in no event be deemed an estoppel or a waiver of the right to

do so thereafter.

4. HOLD HARMLESS PROVISION. In addition to the provisions contained above,

the Owners of all Lots in the Development agree to hold the St. Clair County Drain

Commissioner harmless from any loss, damages or injuries relating to the Drainage Easements

and Drainage Facilities in the Development.

5. SEVERABILITY. If any section, paragraph, clause or phrase of this Agreement is

for any reason held invalid by a court of competent jurisdiction, it is the intent of the undersigned

H-8

that such decision should not affect the validity of the remaining provisions of the Agreement,

which shall be enforced as if the invalid provision did not exist.

6. RECORDING. Upon signing, this Agreement shall be immediately recorded at the

St. Clair County Register of Deeds office. A true copy of the Agreement, as recorded, shall be

provided to the Drain Commissioner.

7. AMENDMENT. This Agreement may not be amended without the express written

consent of the St. Clair County Drain Commissioner.

Dated this _________ day of ____________________, _______.

DEVELOPER:

___________________________________

State of Michigan )

) SS:

County of St. Clair )

On this _________ day of ____________________, 2023, before me personally appeared

________________, to me known to be the person described in and who executed the foregoing

instrument and acknowledged that he / she / they had authority to execute the foregoing

instrument and executed same as his/ her / their free act and deed.

______________________________

Notary Public, St. Clair County, MI

Acting in St. Clair County, MI

My Commission Expires: _________

Drafted By: When Recorded Return To:

Timothy J. Lozen, Esq. [Developer]

901 Huron Ave., Ste. 4

Port Huron, MI 48060

H-9

Example Maintenance Plan and Budget for Development X*

Component Maintenance Activity Frequency Estimated Cost Annual Budget

Catch Basin Sumps Inspect for sediment accumulation and debris Annually $100 $100

Remove sediment accumulation and debris Every 1-3 years $1000 $500

Storm Sewers Inspect for sediment accumulation Annually $100 $100

Remove sediment accumulation Every 5-10 years $1000 $200

Inspect structural elements and compare to Every 5 years $200 $200

as-built construction plans

Detention Basin Mow At least 3 times/year $200 $200

Inspect for sediment accumulation and debris Annually $100 $100

Remove debris Annually $100 $100

Remove sediment accumulation Every 5-10 years $2000 $400

Replace gravel jacket around outlet structure Every 3-5 years $500 $500

Inspect emergency overflow for erosion Annually $100 $100

Reestablish as-built overflow elevation As needed $1000 / 5 years $200

Inspect banks for erosion Annually $100 $100

H-10

Reestablish vegetation on eroded slopes As needed $500 / 5 years $100

Open Channels Mow At least 3 times/year $200 $200

Inspect for sediment accumulation and debris Annually $100 $100

Remove debris Annually $100 $100

Remove sediment accumulation Every 5-10 years $1000 $200

Inspect banks for erosion Annually $100 $100

Reestablish vegetation on eroded slopes As needed $500 / 5 years $100

Record Keeping Record all inspections and maintenance activities As performed $100 $100

Adjust estimated costs for maintenance activities Every five years $100 / 5 years $20

______________________________

Total Annual Budget: $3800

* Maintenance schedule and budget are for example only. Frequency of maintenance activities and costs will vary for each development.

H-11

Operation & Maintenance Plan for

STORM DRAINAGE SYSTEMS

I. Responsibility for Maintenance:

A. During Construction: <name of site> (contractor) has the responsibility to perform the

maintenance

B. Following Construction: <name of site> is responsible to perform the maintenance

C. Routine maintenance of the storm water facilities must be completed on a scheduled basis

by the owner or lessee. All catch basins/manholes/rear yard basins, detention basins, flow

restrictors, or other stormwater structures must be maintained and inspected on a scheduled

basis.

D. If the site is notified by the local DPW, zoning administrator or municipal engineer, either

verbally or in writing, action is required within 10 calendar days of this notification, unless

other acceptable arrangements are made with the <municipality name>. Emergency

maintenance (when there is endangerment to public health, safety or welfare) shall be

performed immediately upon receipt of verbal or written notification. If the <name of site>

fails to act within these timeframes, the <municipality name> or successors may perform the

needed maintenance and assess the cost against the <name of site>, plus an administrative

fee.

II. Funding:

A. The <name of site> is required to pay for all continued maintenance activities.

III. Maintenance Tasks and Schedule:

A. During Construction:

1. Properly plug and abandon existing storm sewer to prevent any sediment from

entering the existing system

2. Establish and maintain ‘BMP’s to prevent sediment from leaving the site.

B. Post Construction:

1. Perform scheduled semi-annual inspections and inspections following major storm

events to check for floatables and debris within the system, especially where the

restrictor is located. Remove floatables and debris as required.

2. Annually inspect for sediment within the catch basin sumps. Removal of sediment

is required if it is within 12 inches (or 50% of sump depth) of an inlet or outlet pipe in

the structure.

3. Every two (2) years inspect the structural elements of the storm system (restrictor,

catch basins, etc.) noting any failures. Correct as needed.

4. If catch basin inserts are in place, inspect every 6 months replace screens, filters,

cloth, as necessary for the particular type of insert.

5. Mow detention basins on a regular basis, no cattails, phragmites or other plants can

grow unrestricted in these basins.

6. Follow manufacturer recommendations for installed devices and structures.

C. Spills:

H-12

1. Identify key spill response personnel and train employees on who they are.

2. Store and maintain appropriate spill cleanup materials in a clearly marked location

near storage areas; and train employees to ensure familiarity with the site's spill

control plan and/or proper spill cleanup procedures.

3. Locate spill cleanup materials, such as absorbents, where they will be readily

accessible (e.g. near storage and maintenance areas).

4. If a spill occurs, notify the key spill response personnel immediately. If the

material is

unknown or hazardous, the local fire department may also need to be

contacted.

5. If the spill gets into the storm drainage system contact the local DPW staff at

_____________________

6. If safe to do so, attempt to contain the material and block the nearby storm drains

that the area impacted is minimized. If the material is unknown or hazardous wait

for

properly trained personnel to contain the materials.

7. Spills or leaks from vehicles in parking lots such as oils, antifreeze, or fuels should

be addressed immediately when noticed by staff working at the site. The spill MUST

be cleaned up using adsorbent materials such as Oil Dry or even kitty litter and then

swept up and disposed of. DO NOT hose down and wash into the storm drain

system, these systems drain directly to rivers in our area and eventually the Great

Lakes.

8. Solid materials should be swept up and disposed of properly. DO NOT hose down

and wash into storm drain system, these systems drain directly to rivers in our area

and eventually to the Great Lakes.

IV. Records:

A. The <name of site> shall keep a written log of both preventive and corrective maintenance

activities. At minimum, the log shall contain the date of the inspection, the reason for the

inspection, the conditions encountered and the resulting activities. The log shall be available

for review at the request of the <name of municipality>. If this site is sold to another, this

Operation and Maintenance agreement must be transferred to the new owner and the <name

of municipality> must be informed of the change in ownership within 14 days of the sale.

V. Site Access

A. If there is a drainage issue/problem on the site that has to do with the storm drainage

system, best management practices, or discharge of too much storm water or water that does

not appear to meet water quality standards, the owner shall allow the municipality or

designee onto the property to inspect the system.

I have read this document and agree to implement the operation and maintenance

procedures listed for this site to protect storm water quality leaving this site.

_________________________________________ ____________________________

Authorized Signature Date

Email address of responsible party: ___________________________________________

I-1

APPENDIX I

EXAMPLE STORMWATER HANDLING STRATEGIES

I-2

I-3

I-4

I-5

I-6

J-1

APPENDIX J

REFERENCE TABLES

J-2

J-3

Table J-1. Rational Method Runoff Coefficients

Surface Runoff Coefficient (C)

Impervious (roof, pavement) 0.90

Typical ¼-acre lot subdivision 0.35

Mowed grass 0.25

Undeveloped farmland/meadow 0.20

Forested 0.15

J-4

Table J-2. Storm Sewer Minimum Slopes

Sewer Diameter (in) Minimum Slope (%)

8 0.50

10 0.40

12 0.33

15 0.25

18 0.22

21 0.20

24 0.17

27 0.16

30 0.15

36 0.13

42 0.11

48 0.10

54 0.09

60 0.09

J-5

Table J-3. Manning “n” Roughness Values

Typical Manning “n” Conservative Manning “n”

Sewer Material Roughness Values Roughness Values

Concrete, Clay 0.013 0.014

Corrugated metal 0.024 0.026

Plastic (smooth lined) 0.010 0.011

J-6

K-1

APPENDIX K

EXAMPLE BIORETENTION DETAILS

K-2

K-3

Typical Bioretention System

K-4

Typical Bioretention Section Detail

L-1

APPENDIX L

EXAMPLE INFILTRATION DETAILS

L-2

L-3

Typical Infiltration Basin

Typical Infiltration Section Detail

L-4

M-1

APPENDIX M

EXAMPLE DETENTION BASIN DETAILS

M-2

M-3

M-4

M-5

M-6

APPENDIX N

EXAMPLE CALCULATIONS

Example 1: Detention Basin Design

A 10-acre parcel is to be developed into a single-family residential subdivision. A detention

basin will be provided to control the release of stormwater runoff to a nearby established drain.

No off-site area drains onto or across the developing site. The predevelopment runoff coefficient

for the site is 0.20.

A hydraulic analysis of the proposed storm sewer indicates that the design water elevation of the

basin cannot exceed elevation 585.00 ft to maintain the hydraulic grade line in the storm sewer at

least one foot below all catch basin and manhole rim elevations. The bottom of the detention

volume in the basin must be at or above the invert of the storm sewer conveying the basin

outflow to the receiving watercourse. It must also be above base flow elevation in the drain and

above the groundwater table. The receiving watercourse in this case is an existing established

drain, which maintains a dry weather base flow with a depth of approximately 6 inches. At the

location where the detention basin outlet pipe will tap the drain, the drain bottom is at elevation

580.00 ft. The basin outlet will be located 400 feet away from the drain. The groundwater table

was determined by soil borings to be at elevation 578.00 ft.

STEP 1. Size the storm sewer extending from the basin to the drain.

The 10-year peak flow to the basin = Q

= C x I x A

weighted

= 0.34 C

weighted

= (30% impervious)(0.9) + (70% pervious)(0.2) = 0.41

T = 28 minutes (determined by storm sewer design calculations)

I = 175 / (T + 25) = 3.30 in/hr

A = 10 acres

= C x I x A = (0.41) x (3.30 in/hr) x (10 acres) = 13.5 cfs

At slope of 0.17%, a 27-inch concrete storm sewer would have a capacity of 13.8 cfs.

Therefore, use 27-inch storm sewer at 0.17%.

STEP 2. Set basin floor (or permanent pool) elevation.

Sewer invert at basin outlet = Receiving watercourse bottom elevation + (length of

outlet sewer) x (slope of outlet sewer)

Sewer invert at basin outlet = 580.00 + 400 ft x 0.0017 = 580.68 ft

Since the base flow in the drain is at elevation 580.50 ft, and the groundwater table is at

elevation 578.00 ft, the sewer invert at the basin outlet (elev. 580.68 ft) will control the

minimum elevation of the detention volume in the basin.

Set basin floor (or permanent pool) elevation to at or above 580.68 feet, say 581.00 feet.

STEP 3. Determine the required basin volume for 100-year storm.

A = 10 acres

allowable

= Q

= 0.15 cfs/ac x 10 ac = 1.5 cfs

= Q

/ A C = 1.5 cfs / (10 ac x 0.41) = 0.366 cfs/impervious acre

Storage Time = T = -25 + sqrt(10,312.5 / Q

) = 143 minutes

Volume per impervious acre = V

= 16,500 T / (T + 25) – 40 Q

T = 11,952 cf / imp-ac

Required Storage Volume = V

x A x C = (11,952) x (10 ac) x (0.41) = 49,003 cf

STEP 4. Design the basin outlet standpipe.

Available basin depth = 586.00 ft – 581.00 ft = 5.0 ft

Stage-Storage Curve for proposed basin (assume 1:6 side slopes):

Elev (ft) Area (sf) Depth (ft) Volume (cf) Cumulative

Volume (cf)

586.0

18,769

17,197

58,865

585.0

15,625

14,197

41,668

584.0

12,769

11,485

27,471

583.0

10,201

9,061

15,986

582.0

7921

6,925

581.0

5929

First Flush

First Flush Storage Volume = 1 in x 10 ac x 0.41 x 43,560 sf/ac x 1 ft/12 in = 14,883 cf

Depth of First Flush Volume in proposed basin:

(15,986 – 14,883 cf) / (15,986 – 6,925 cf) = (583 ft – FF Elev.) / (583 – 582 ft)

FF Elev. = 582.88 ft

Release First Flush Volume over 24 hours:

average

= 14,883 cf / 24 hrs x 1 hr/3600 s = 0.172 cfs

Average head on orifice outlet:

average

= 2/3 (582.88 – 581.0 ft) = 1.253 ft

Area of First Flush orifices:

= 0.172 cfs / 0.62 sqrt(2 g H

average

) = 0.031 sf

Since a 1-inch orifice has an area of 0.00545 sf, use five 1-inch orifices in 36-inch

standpipe at elev. 581.00 ft

Bankfull Flood (Stream Protection)

Bankfull Flood Vol. = 2.30 in x 10 ac x (0.41-0.20) x 43,560 sf/ac x 1 ft/12 in = 17,533 cf

Depth of Bankfull Flood Volume in proposed basin:

(27,471 – 17,545 cf) / (27,471 – 15,986) = (584.0 – BF Elev.) / (584.0 – 583.0 ft)

BF Elev. = 583.14 ft

Release Bankfull Flood Volume over 48 hours maximum.

Determine discharge rate of Bankfull Flood Volume through First Flush orifices:

average

= 2/3 (583.14 – 581.0 ft) = 1.43 ft

= 0.62 (5) (0.00545 sf) sqrt(2 g H

average

) = 0.162 cfs

Check detention time for Bankfull Flood Volume:

17,533 cf / 0.162 cfs x 1 hr/3600 s = 30.1 hrs

Since this does not exceed the desired 48-hour maximum detention time, no additional

orifices are required at Elev. 582.88 ft

100-year Flood

Depth of 100-year Flood Volume in proposed basin:

(58,865 – 49,003 cf) / (58,865 – 41,668) = (586.0 – Elev.) / (586.0 – 585.0 ft)

Elev. = 585.43 ft

Determine discharge rate of 100-year Flood Volume through First Flush and Bankfull

Flood orifices:

= 0.62 (0) (0.00545 sf) sqrt(2 g (585.43 – 582.88 ft)) = 0.0 cfs

= 0.62 (5) (0.00545 sf) sqrt(2 g (585.43 – 581.00 ft)) = 0.285 cfs

Determine discharge rate of 100-year Flood Volume through 100-year Flood orifices:

– Q

= 1.5 – 0.0 – 0.285 cfs = 1.215 cfs

Head on 100-year Flood orifices:

H = 585.43 – 583.14 ft = 2.29 ft

Area of 100-year Flood orifices at Elev. 583.14 ft:

A = 1.215 cfs / (0.62 sqrt(2 g H)) = 0.161 sf

Since a 2-inch orifice has an area of 0.022 sf, use seven 2-inch orifices at Elev. 583.14 ft

STEP 5. Verify that at least one foot of freeboard is being provided.

Design water elevation = 585.43 ft

Detention basin banks and surrounding ground elevation = 587 ft +/-

Therefore, more than one foot of freeboard is being provided.

STEP 6. Design overflow spillway.

Peak 10-year flow into basin = 13.5 cfs

Since head over weir must be less than 1 foot so as not to exceed the available freeboard,

Q = C x L x H

1.5

L = Q / ( C x H

1.5

)

L = 13.5 cfs / ( 3 x 1

1.5

)

L = 4.5 ft, say 5 ft

Set length of overflow spillway to at least 5 feet.

Example 2: Retention Basin Design

A 10-acre parcel is to be developed into a single-family residential subdivision. A retention

basin will be provided to capture the stormwater runoff from the site. No off-site area drains

onto or across the developing site.

A hydraulic analysis of the proposed storm sewer indicates that the design water elevation of the

basin cannot exceed elevation 585.00 ft to maintain the hydraulic grade line in the storm sewer at

least one foot below all catch basin and manhole rim elevations. The bottom of the retention

volume in the basin must be at or above the groundwater table, which was determined by soil

borings to be at elevation 578.00 ft.

STEP 1. Determine the soil types in the tributary area (from the United States Department of

Agriculture Soil Survey for St. Clair County), and classify these soil types by Hydrologic Soil

Group (per Michigan Department of Environmental Quality’s “Computing Flood Discharges for

Small Ungaged Watersheds” by Sorrell, July 2003).

50% Hydrologic soil group A

50% Hydrologic soil group B

The retention basin will be located in an area that (primarily) consists of soils from

hydrologic soil group B.

STEP 2. Determine the weighted Runoff Curve Number for the site (per SCS Method).

For this example, assume initially that the retention basin area will be 10% of the area of

the site.

Hydrologic Percent of Total Percent of Partial

Soil Group Drainage Area Land Use Soil Group RCN RCN

A 59 Single-fam. Res. (1/4-ac) 100 61 36.0

B 41 Single-fam. Res. (1/4-ac) 76 75 23.4

Retention basin 24 100 9.9

_______

Composite RCN = 69.3

STEP 3. Determine the 100-year, 24-hour precipitation total for the area, P

Per NOAA Atlas 14 (Volume 8, Version 2), the 100-year, 24-hour storm consists of 5.19

inches of rainfall (P = 5.19).

STEP 4. Calculate the storage, S (per SCS Method).

S = 1000 / RCN – 10 = 1000 / 69.3 – 10 = 4.43 in

STEP 5. Calculate the stormwater runoff for a 100-year, 24-hour storm, SRO (per SCS Method).

SRO = ( P – 0.2S )

/ ( P + 0.8S ) = ( 5.19 – 0.2 x 4.43 )

/ ( 5.19 + 0.8 x 4.43 ) = 2.12 in

STEP 6. Determine the runoff volume for a 100-year, 24-hour storm from the site.

Runoff Volume = 2.12 in x 10 acres x 1 ft/12 in x 43,560 sf/1 ac = 76,956 cf

STEP 7. Determine stage-storage curve for proposed retention basin.

The available storage must equal or exceed twice the runoff volume for a 100-year, 24-

hour storm: 2 x 76,956 = 153,912

Stage-Storage Curve (assume 1:6 side slopes):

Elev (ft) Area (sf) Depth (ft) Volume (cf) Cumulative

Volume (cf)

586.0

46,208

42,704

166,944

585.0

39,200

35,984

124,240

584.0

32,768

29,840

88,256

583.0

26,912

24,272

58,416

582.0

21,632

19,280

34,144

581.0

16,928

14,864

580.0

12,800

STEP 8. Determine the design water elevation (DWE) in the retention basin.

(166,944 – 153,912 cf) / (166,944 – 124,240) = (586.0 – DWE) / (586.0 – 585.0 ft)

DWE = 585.69 ft

STEP 9. Check assumption that retention basin area is approximately 10% of total site area.

Design water elevation is 585.81 ft, say 586 ft

Area of basin at elevation 586 feet is 46,208 sf

Basin area is approximately 46,208 sf / 435,600 sf = 10.6% of total area

Assumption that basin area is about 10% of total area is valid.

STEP 10. Verify that at least one foot of freeboard is being provided.

Design water elevation = 585.69 ft

Retention basin banks and surrounding ground elevation = 587 ft +/-

More than one foot of freeboard is being provided.

STEP 11. Design overflow spillway.

Peak 10-year flow into basin, Q = C x I x A

Q = 0.35 x 175 / (T + 25) x 10 ac, where T is estimated to be 20 minutes

Q = 13.6 cfs

Since head over weir must be less than 1 foot so as not to exceed the available freeboard,

Q = C x L x H

1.5

L = Q / ( C x H

1.5

)

L = 13.6 cfs / ( 3 x 1

1.5

)

L = 4.5 ft, say 5 ft

Set length of overflow spillway to at least 5 feet.

Example 3: Culvert Design Calculation

A 12-acre parcel is to be developed into an apartment complex. The entrance driveway to the

development will cross an established drain that flows west along the roadside. A 60-ft. culvert

is proposed to allow the flow in the drain to cross the entrance driveway. The proposed

development drains via overland flow south into the drain. Nine acres of undeveloped land just

north of the proposed subdivision drains across the site to the drain. Further upstream in the

watershed, another ten acres of single-family residential subdivision and eight acres of

undeveloped area also drains into drain. (See figure below.)

STEP 1. Determine the peak design flow to the proposed culvert.

A USGS map indicates that the proposed site and upstream off-site area are tributary to

the proposed culvert, as well as a 10-acre residential subdivision and an 8-acre

undeveloped parcel. Since less than 2 square miles of area are tributary to the culvert, the

culvert will be designed for the 10-year peak flow per county standards, rather than for

the 100-year peak flow per state standards.

All the area except the 8-acre undeveloped parcel will pass through detention, so assume

a peak flow from this tributary area of 0.15 cfs/acre.

detention

= (12 + 9 + 10 acres) x 0.15 cfs/acres = 4.7 cfs

Assume that the future use of the undeveloped area is multiple-family residential, but

without detention. Use Rational Method to estimate the 10-year peak flow from this area.

future multiple-family residential

= C I A

future multiple-family residential

= 0.5 x (175 / T + 25) x 8 acres Estimate T = 20 min

future multiple-family residential

= 0.5 x 3.89 in/hr x 8 acres

future multiple-family residential

= 15.6 cfs

Add peak flows:

total

= 15.6 + 4.7 = 20.3 cfs

STEP 2. Estimate tailwater elevation for proposed culvert.

The typical cross-section of the drain is 4 feet deep, with a 1-ft bottom width and 1:3 side

slopes. The typical drain slope downstream of the proposed culvert is 0.002 (0.2%).

Using Manning’s equation, the normal depth of flow for 20.3 cfs in this drain would be

Q = 1.49 R

0.67

0.5

A / n where R

= hydraulic radius of flow

= area / wetted perimeter

S = slope of drain

A = area of flow

n = channel roughness (assume 0.04)

Solving for the normal depth of flow yields:

= 1.88 feet = tailwater elevation for culvert

STEP 3. Size culvert so that the headwater remains at least one foot below driveway and

roadway elevations, and the backwater does not extend beyond the limits of the site.

Use a culvert hydraulic analysis program such as the Federal Highway Administration’s

HY-8, or standard inlet and outlet control nomographs. Assume the proposed culvert is a

round, corrugated metal pipe (CMP).

Propose a 30-inch CMP culvert at a slope of 0.2% with upstream and downstream invert

elevations: 800.06 ft and 799.94 ft, respectively.

Per FHWA HY-8, Inlet control headwater elev. = 802.61 ft

Outlet control headwater elev. = 803.00 ft

Therefore, the culverts will be under outlet control with a headwater elev. = 803.00 ft

Since the proposed driveway centerline elevation is 804.0 ft, the headwater elevation is

more than one foot below the banks.

The elevation of the normal depth of flow at the upstream property line is greater than

804.0 ft. The backwater would not extend onto upstream off-site property.

STEP 4. Verify that 100-year peak flow headwater elevation will remain below adjacent

proposed and existing structures.

All the area except the 8-acre undeveloped parcel will pass through detention, so assume

a peak flow from this tributary area of 0.15 cfs/acre.

detention

= (12 + 9 + 10 acres) x 0.15 cfs/acres = 4.7 cfs

Assume that the future use of the undeveloped area is multiple-family residential, but

without detention. Use Rational Method to estimate the 100-year peak flow from this

area.

undeveloped

= C I A

undeveloped

= 0.5 x (275 / T + 25) x 8 acres Estimate T = 20 minutes

undeveloped

= 0.5 x 6.11 in/hr x 8 acres

undeveloped

= 24.4 cfs

Add peak flows:

total

= 24.4 + 4.7 = 29.1 cfs

Using Manning’s equation to find the tailwater on the culvert yields

= 2.22 feet = tailwater elevation for culvert

HY-8 (or the culvert nomographs) indicates that the culvert would be under outlet control

with a headwater elevation of 804.04 feet.

The lowest nearby structure has a finished floor elevation of 805.0 feet. Therefore, all

nearby structures would be above the 100-year headwater elevation for the culvert.

Proposed Site

for Apartments

(12 acres)

Proposed Culvert

County Drain

Off-site Area

draining across

Proposed Site

(9 acres)

North

Undeveloped

Area –

Future

Multiple

Family

Residential

(8 acres)

Residential

Subdivision

(10 acres)

Detention basins

N-14

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APPENDIX O

EXAMPLE OIL REMOVAL BMP’S (BEST MANAGEMENT PRACTICES)

O-2

O-3

Oil Removal BMP – Low Oil Application

For low oil applications, a typical detention basin outlet may be equipped with an oil skimmer,

consisting of a non-leaching absorbent material, connected to the rim of the standpipe with a

non-degradable line or rope. A typical standpipe would require one 13-inch x 13-inch packet of

absorbent material that converts liquid petroleum hydrocarbons into a manageable solid waste

(i.e. not a hazardous waste). An acceptable product would be the “Smart Sponge® Passive

Skimmer” or equal. The length of the connecting line should be such that the skimmer, when

hanging freely, rests above the crown of the outlet pipe extending from the standpipe. The

skimmer shall not cause an obstruction to the flow exiting the standpipe. Additional information

on the “Smart Sponge® Passive Skimmer” can be found on the following page.

Oil Removal BMP – High Oil Application

For high oil applications, one or more prefabricated oil/grit separator units may be required. The

following design standards shall apply to such units:

 Each oil separator shall serve no more than one acre of (impervious) area.

 The separator shall be designed to pass the ten-year design storm without hydraulic

interference.

 Oil separators shall consist of at least three chambers: a sediment chamber, an oil

chamber, and a discharge chamber.

 The first two chambers shall provide at least 400 cubic feet of grit storage, with

permanent pool depth of at least 4 feet.

 The first and second chambers (sediment chamber and oil chamber) shall be hydraulically

connected by two 6-inch orifices protected by a trash rack. The orifices shall be located

at least 4 feet above the separator floor.

 The second and third chambers (oil chamber and discharge chamber) shall be

hydraulically connected by an inverted elbow at least 18 inches in diameter, 3 feet in

length and at least one foot above the oil chamber floor.

 A manhole shall be provided to each chamber for maintenance.

 The outlet from the oil separator shall not be submerged by the receiving watercourse

during a 10-year design storm.

O-4

P-1

APPENDIX P

GLOSSARY

P-2

P-3

Glossary

Best Management Practice Also “BMP”. A practice or combination of practices based on

current, accepted engineering standards that prevent or reduce

stormwater runoff and/or associated pollutants. For example, the

Guidebook of Best Management Practices for Michigan

Watersheds.

Construction Plans Detailed plans showing the existing and proposed features of a

proposed development and engineering calculations supporting the

design of the proposed features.

County Drain A drain which has been designated as an Established Drain wholly

within St. Clair County.

Design Storm A rainfall event of specified return frequency and duration (e.g. a

100-year, 24-hour storm) that is used to calculate peak flows and

/or runoff volumes.

Detention Basin A stormwater management practice that captures stormwater

runoff temporarily and releases the stormwater to a surface water

body or watercourse

Development A residential, industrial, municipal, commercial, or other project

involving the construction of structures and/or paved surfaces on

natural or previously developed land.

Drain The term “drain” as used in these Rules shall have the meaning as

proscribed in Drain Code Section 3 as follows: The word “drain”,

whenever used in this act, shall include the main stream or trunk

and all tributaries or branches of any creek or river, any

watercourse or ditch, either open or closed, any covered drain, any

sanitary or any combined sanitary and storm sewer or storm sewer

or conduit composed of tile, brick, concrete, or other material, any

structures or mechanical devices, that will properly purify the flow

of such drains, any pumping equipment necessary to assist or

relieve the flow of such drains and any levee, dike, barrier, or a

combination of any or all of same constructed, or proposed to be

constructed, for the purpose of drainage or for the purification of

the flow of such drains, but shall not include any dam and flowage

rights used in connection therewith which is used for the

generation of power by a public utility subject to regulation by the

public service commission.

Drain Commissioner The Drain Commissioner of the County of St. Clair, Michigan.

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Drainage District The term “drainage district” as used in these Rules shall have the

meaning as proscribed in Drain Code Section 5 as follows: A

Drainage District is any county or inter-county drainage district

legally established pursuant to applicable provisions of the Drain

Code. Drain Code Section 5 provides that each such drainage

district is a body corporate with the power to contract, to sue and

be sued, and to hold, manage and dispose of real property, in

addition to any other powers conferred by law. Generally, a

drainage district is comprised of all lands which drain to a legally

established drain.

Easement Also “Right-of-way”. A legal right granted by a property owner to

another entity, allowing that entity to make limited use of the

property for a specific purpose. The Drain Commissioner secures

easements along established drains, detention and retention basins,

and other stormwater conveyance systems for the purpose of

maintenance access.

Established Drain An open or enclosed stormwater conveyance system that has been

legally established as a county or inter-county drain within St.

Clair County pursuant to applicable provisions of the Drain Code.

Final Plat A map of all or part of a subdivision prepared and certified by the

proprietor’s Engineer or Land Surveyor in accordance with the

requirements of the Subdivision Control Act of 167, Act 288 of the

Public Acts of 1967, as amended.

First Flush During the early stages of a storm, stormwater with a highly

concentrated pollutant load, due to the runoff washing away the

pollutants that have accumulated on the land.

Freeboard The vertical distance from the top of an embankment to the design

water elevation of a detention basin or retention basin, required as

a safety margin.

Headwater The depth of water at the upstream end of a culvert.

Infiltration The absorption of water into the ground, often expressed in terms

of inches per hour.

Inter-county Drain A drain traversing two or more counties that has been legally

established as an established drain.

Invert The interior surface of the bottom of a pipe.

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Pre-Preliminary Plans A sketch plan or informal plan drawn to scale and showing the

existing features of a site and its surroundings and the general

layout of the proposed development.

Pre-Preliminary Plat A sketch plan or informal plan drawn to scale and showing the

existing features of a site and its surroundings and the general

layout of the proposed subdivision.

Preliminary Plans A plan showing the preliminary layout of a development in

sufficient detail to allow review by interested agencies.

Preliminary Plat A plan showing the preliminary layout of a subdivision

development in sufficient detail to allow review by interested

agencies.

Proprietor A person, firm, association, partnership, corporation or

combination of any of them which may hold ownership in land

whether recorded or not. “Proprietor” shall be synonymous with

“Developer” or “Land owner”.

Retention Basin A stormwater management practice that captures stormwater

runoff and does not discharge to a surface water body or

watercourse, but allows the water to evaporate or infiltrate into the

ground.

Redevelopment Additions and/or modifications to an existing development.

Riprap A combination of large stone, cobbles, and boulders used to line

channels, stabilize banks, reduce runoff velocities, or filter out

sediment.

Runoff The excess portion of precipitation that does not infiltration into

the ground or is not captured by vegetation, but flows overland to a

stream, storm sewer, or water body.

Spillway A depression in the embankment of a detention basin used to allow

overflow of stormwater during storm events in excess of the design

storm.

Tailwater The depth of water at the downstream end of a culvert.

Time of Concentration The time it takes for surface runoff to travel from the hydraulically

farthest portion of a watershed to the design point.