Page 1 of 61 Ohio EPA Permit No.: OHC000006

Page 1 of 61

Ohio EPA Permit No.: OHC000006

Effective Date: April 23, 2023

Expiration Date: April 22, 2028

OHIO ENVIRONMENTAL PROTECTION AGENCY

GENERAL PERMIT AUTHORIZATION FOR STORMWATER DISCHARGES ASSOCIATED

WITH CONSTRUCTION ACTIVITY UNDER THE NATIONAL POLLUTANT

DISCHARGE ELIMINATION SYSTEM

In compliance with the provisions of the federal Water Pollution Control Act, as amended (33

U.S.C. Section 1251 et. seq. hereafter referred to as "the Act") and the Ohio Water Pollution

Control Act [Ohio Revised Code (“ORC”) Chapter 6111], dischargers of stormwater from sites

where construction activity is being conducted, as defined in Part I.B of this permit, are

authorized by the Ohio Environmental Protection Agency, hereafter referred to as "Ohio EPA,"

to discharge from the outfalls at the sites and to the receiving surface waters of the state

identified in their Notice of Intent (“NOI”) application form on file with Ohio EPA in accordance

with the conditions specified in Parts I through VII of this permit.

It has been determined that a lowering of water quality of various waters of the state associated

with granting coverage under this permit is necessary to accommodate important social and

economic development in the state of Ohio. In accordance with OAC 3745-1-05, this decision

was reached only after examining a series of technical alternatives, reviewing social and

economic issues related to the degradation, and considering all public and intergovernmental

comments received concerning the proposal.

This permit is conditioned upon payment of applicable fees, submittal of a complete NOI

application form, development (and submittal, if applicable) of a complete Stormwater Pollution

Prevention Plan (SWP3) and written approval of coverage from the director of Ohio EPA in

accordance with Ohio Administrative Code (“OAC”) Rule 3745-38-02.

____________________________

Anne M. Vogel

Director

2023-04-11 19:00:28 UTC

E-SIGNED by Anne Vogel

on 2023-04-11 19:00:28 GMT

Ohio EPA

Entered Director’s Journal

04/11/2023

I certify this to be a true and accurate copy of the

official documents as filed in the records of the Ohio

Environmental Protection Agency.

By: Date:

04/11/2023

Page 2 of 61 
Ohio EPA Permit No.: OHC000006 
 
 
TABLE OF CONTENTS 
PART I.  COVERAGE UNDER THIS PERMIT ............................................................................................................... 3 
A.  Permit Area. ...................................................................................................................................................... 3 
B.  Eligibility. ........................................................................................................................................................... 3 
C.  Requiring an individual NPDES permit or an alternative NPDES general permit. ............................................. 5 
D.  Permit requirements when portions of a site are sold ....................................................................................... 6 
E.  Authorization ..................................................................................................................................................... 6 
F.  Notice of Intent Requirements ........................................................................................................................... 7 
Part II. NON-NUMERIC EFFLUENT LIMITATIONS ....................................................................................................... 8 
A.  Erosion and Sediment Controls. ....................................................................................................................... 8 
B.  Soil Stabilization. ............................................................................................................................................... 9 
C.  Dewatering ........................................................................................................................................................ 9 
D.  Pollution Prevention Measures. ...................................................................................................................... 10 
E.  Prohibited Discharges. .................................................................................................................................... 10 
F.  Surface Outlets ............................................................................................................................................... 10 
G.  Post-Construction Stormwater Management Controls. ................................................................................... 10 
PART III.  STORMWATER POLLUTION PREVENTION PLAN (SWP3) ..................................................................... 10 
A.  Stormwater Pollution Prevention Plans. .......................................................................................................... 10 
B.        Timing. .......................................................................................................................................................... 11 
C.  SWP3 Signature and Review. ......................................................................................................................... 11 
D.  Amendments. .................................................................................................................................................. 12 
E.  Duty to inform contractors and subcontractors. ............................................................................................... 13 
F.  Total Maximum Daily Load (TMDL) allocations. .............................................................................................. 13 
G.  SWP3 Requirements....................................................................................................................................... 13 
PART IV.  NOTICE OF TERMINATION REQUIREMENTS ......................................................................................... 32 
A.  Failure to notify. .............................................................................................................................................. 32 
B.  When to submit an NOT. ................................................................................................................................. 33 
C.  How to submit an NOT. ................................................................................................................................... 33 
PART V.  STANDARD PERMIT CONDITIONS. ........................................................................................................... 34 
A.  Duty to comply. ............................................................................................................................................... 34 
B.  Continuation of an expired general permit. ..................................................................................................... 34 
C.  Need to halt or reduce activity not a defense. ................................................................................................. 34 
D.  Duty to mitigate. .............................................................................................................................................. 34 
E.  Duty to provide information. ............................................................................................................................ 34 
F.  Other information. ........................................................................................................................................... 34 
G.  Signatory requirements. .................................................................................................................................. 34 
H.  Certification. .................................................................................................................................................... 36 
I.  Oil and hazardous substance liability .............................................................................................................. 36 
J.  Property rights. ................................................................................................................................................ 36 
K.  Severability. .................................................................................................................................................... 36 
L.  Transfers. ........................................................................................................................................................ 36 
M.  Environmental laws. ........................................................................................................................................ 36 
N.  Proper operation and maintenance. ................................................................................................................ 37 
O.  Inspection and entry. ....................................................................................................................................... 37 
P.  Duty to Reapply. ............................................................................................................................................. 37 
Q.  Permit Actions. ................................................................................................................................................ 37 
R.  Bypass. ........................................................................................................................................................... 37 
S.  Upset............................................................................................................................................................... 37 
T.  Monitoring and Records. ................................................................................................................................. 38 
U.  Reporting Requirements. ................................................................................................................................ 38 
V.  General Effluent Limitation .............................................................................................................................. 38 
PART VI.  REOPENER CLAUSE ................................................................................................................................. 38 
PART VII. DEFINITIONS ............................................................................................................................................. 38 
APPENDICES .............................................................................................................................................................. 44 
Appendix A. Big Darby Creek Watershed ................................................................................................................ 44 
Appendix B. Olentangy River Watershed ................................................................................................................. 55 
 
 
 
 

Page 3 of 61

Ohio EPA Permit No.: OHC000006

PART I. COVERAGE UNDER THIS PERMIT

A. Permit Area.

This permit covers the entire State of Ohio. Appendices A and B of this permit contain additional

watershed specific requirements for construction activities located partially or fully within the Big

Darby Creek Watershed and portions of the Olentangy River Watershed.

B. Eligibility.

1. Construction activities covered. Except for stormwater discharges identified under Part

I.B.2, this permit may cover all new and existing discharges composed entirely of

stormwater discharges associated with construction activity that enter surface waters of

the state or a storm drain leading to surface waters of the state.

For the purposes of this permit, construction activities include any clearing, grading,

excavating, grubbing and/or filling activities that disturb one or more acres. Discharges

from trench dewatering are also covered by this permit as long as the dewatering activity

is carried out in accordance with the practices outlined in Part III.G.2.g.iv of this permit.

Construction activities disturbing one or more acres of total land or will disturb less than

one acre of land but are part of a larger common plan of development or sale that will

ultimately disturb one or more acres of land are eligible for coverage under this permit.

The threshold acreage includes the entire area disturbed in the larger common plan of

development or sale.

This permit also authorizes stormwater discharges from support activities (e.g., concrete

or asphalt batch plants, equipment staging yards, material storage areas, excavated

material disposal areas, borrow areas) provided:

a. The support activity is directly related to a construction site that is required to

have NPDES permit coverage for discharges of stormwater associated with

construction activity;

b. The support activity is not a commercial operation serving multiple unrelated

construction projects and does not operate beyond the completion of the

construction activity at the site it supports;

c. Appropriate controls and measures are identified in a stormwater pollution

prevention plan (SWP3) covering the discharges from the support activity; and

d. The support activity is on or contiguous with the property defined in the NOI

(offsite borrow pits and soil disposal areas, which serve only one project, do not

have to be contiguous with the construction site).

2. Limitations on coverage. The following stormwater discharges associated with

construction activity are not covered by this permit:

a. Stormwater discharges that originate from the site after construction activities have

ceased, including any temporary support activity, and the site has achieved final

Page 4 of 61

Ohio EPA Permit No.: OHC000006

stabilization. Industrial post-construction stormwater discharges may need to be

covered by an NPDES permit;

b. Stormwater discharges associated with construction activity that the director has

shown to be or may reasonably expect to be contributing to a violation of a water

quality standard and such discharge would be a violation of this permit; and

c. Stormwater discharges authorized by an individual NPDES permit or another

NPDES general permit.

3. Waivers. After March 10, 2003, sites whose larger common plan of development or sale

have at least one, but less than five acres of land disturbance, which would otherwise

require permit coverage for stormwater discharges associated with construction

activities, may request that the director waive their permit requirement. Entities wishing

to request such a waiver must certify in writing that the construction activity meets one of

the two waiver conditions:

a. Rainfall Erosivity Waiver. For a construction site to qualify for the rainfall erosivity

waiver, the cumulative rainfall erosivity over the project duration must be five or less

and the site must be stabilized with a least a 70 percent vegetative cover or other

permanent, non-erosive cover. The rainfall erosivity must be calculated according to

the method in U.S. EPA Fact Sheet 3.1 Construction Rainfall Erosivity Waiver dated

January 2001 and be found at: https://epa.ohio.gov/divisions-and-

offices/surface-water/permitting/stormwater-program. If it is determined that a

construction activity will take place during a time period where the rainfall erosivity

factor is less than five, a written waiver certification must be submitted to Ohio EPA

at least 21 days before construction activity is scheduled to begin. If the construction

activity will extend beyond the dates specified in the waiver certification, the operator

must either: (a) recalculate the waiver using the original start date with the new

ending date (if the R factor is still less than five, a new waiver certification must be

submitted) or (b) submit an NOI application form and fee for coverage under this

general permit at least seven days prior to the end of the waiver period; or

b. TMDL (Total Maximum Daily Load) Waiver. Stormwater controls are not needed

based on a TMDL approved or established by U.S. EPA that addresses the

pollutant(s) of concern or, for non-impaired waters that do not require TMDLs, and

equivalent analysis that determines allocations for small construction sites for the

pollutant(s) of concern or that determines that such allocations are not needed to

protect water quality based on consideration of existing in-stream concentrations,

expected growth in pollutant contributions from all sources, and a margin of safety.

The pollutant(s) of concern include sediment or a parameter that addresses

sediment (such as total suspended solids, turbidity or siltation) and any other

pollutant that has been identified as a cause of impairment of any water body that will

receive a discharge from the construction activity. The operator must certify to the

director of Ohio EPA that the construction activity will take place, and stormwater

discharges will occur, within the drainage area addressed by the TMDL or equivalent

analysis. A written waiver certification must be submitted to Ohio EPA at least 21

days before the construction activity is scheduled to begin.

Page 5 of 61

Ohio EPA Permit No.: OHC000006

4. Prohibition on non-stormwater discharges. All discharges covered by this permit must

be composed entirely of stormwater with the exception of the following: discharges from

firefighting activities; fire hydrant flushings; potable water sources including waterline

flushings; irrigation drainage; lawn watering; routine external building washdown which

does not use detergents; pavement washwaters where spills or leaks of toxic or

hazardous materials have not occurred (unless all spilled material has been removed)

and where detergents are not used; air conditioning condensate; springs;

uncontaminated groundwater from trench or well point dewatering and foundation or

footing drains where flows are not contaminated with process materials such as

solvents. Dewatering activities must be done in compliance with Part II.C and Part

III.G.2.g.iv of this permit. Discharges of material other than stormwater or the authorized

non-stormwater discharges listed above must comply with an individual NPDES permit

or an alternative NPDES general permit issued for the discharge.

Except for flows from firefighting activities, sources of non-stormwater listed above that

are combined with stormwater discharges associated with construction activity must be

identified in the SWP3. The SWP3 must identify and ensure the implementation of

appropriate pollution prevention measures for the non-stormwater component(s) of the

discharge.

5. Spills and unintended releases (Releases in excess of Reportable Quantities). This

permit does not relieve the permittee of the reporting requirements of Title 40 of the

Code of Federal Regulations (“CFR”) Part 117 and 40 CFR Part 302. In the event of a

spill or other unintended release, the discharge of hazardous substances in the storm

water discharge(s) from a construction site must be minimized in accordance with the

applicable stormwater pollution prevention plan for the construction activity and in no

case, during any 24-hour period, may the discharge(s) contain a hazardous substance

equal to or in excess of reportable quantities.

40 CFR Part 117 sets forth a determination of the reportable quantity for each substance

designated as hazardous in 40 CFR Part 116. The regulation applies to quantities of

designated substances equal to or greater than the reportable quantities, when

discharged to surface waters of the state. 40 CFR Part 302 designates under section

102(a) of the Comprehensive Environmental Response, Compensation and Liability Act

of 1980, those substances in the statutes referred to in section 101(14), identifies

reportable quantities for these substances and sets forth the notification requirements for

releases of these substances. This regulation also sets forth reportable quantities for

hazardous substances designated under section 311(b)(2)(A) of the Clean Water Act

(CWA).

C. Requiring an individual NPDES permit or an alternative NPDES general permit.

1. The director may require an alternative permit. The director may require any operator

eligible for this permit to apply for and obtain either an individual NPDES permit or

coverage under an alternative NPDES general permit in accordance with OAC Rule

3745-38-02. Any interested person may petition the director to take action under this

paragraph.

The director will send written notification that an alternative NPDES permit is required.

This notice shall include a brief statement of the reasons for this decision, an application

Page 6 of 61

Ohio EPA Permit No.: OHC000006

form and a statement setting a deadline for the operator to file the application. If an

operator fails to submit an application in a timely manner as required by the director

under this paragraph, then coverage, if in effect, under this permit is automatically

terminated at the end of the day specified for application submittal.

2. Operators may request an individual NPDES permit. Any owner or operator eligible for

this permit may request to be excluded from the coverage of this permit by applying for

an individual permit. The owner or operator shall submit an individual application with

reasons supporting the request to the director in accordance with the requirements of 40

CFR 122.26. If the reasons adequately support the request, the director shall grant it by

issuing an individual NPDES permit.

3. When an individual NPDES permit is issued to an owner or operator otherwise subject to

this permit or the owner or operator is approved for coverage under an alternative

NPDES general permit, the applicability of this permit to the individual NPDES permittee

is automatically terminated on the effective date of the individual permit or the date of

approval for coverage under the alternative general permit, whichever the case may be.

D. Permit requirements when portions of a site are sold

If an operator obtains a permit for a development, and then the operator (permittee) sells off lots

or parcels within that development, permit coverage must be continued on those lots until a

Notice of Termination (NOT) in accordance with Part IV.B is submitted. For developments

which require the use of centralized sediment and erosion controls (i.e., controls that address

stormwater runoff from one or more lots) for which the current permittee intends to terminate

responsibilities under this permit for a lot after sale of the lot to a new owner and such

termination will either prevent or impair the implementation of the controls and therefore

jeopardize compliance with the terms and conditions of this permit, the permittee will be

required to maintain responsibility for the implementation of those controls. For developments

where this is not the case, it is the permittee’s responsibility to temporarily stabilize all lots sold

to individual lot owners unless an exception is approved in accordance with Part III.G.4. In

cases where permit responsibilities for individual lot(s) will be terminated after sale of the lot, the

permittee shall inform the individual lot owner of the obligations under this permit and ensure

that the Individual Lot NOI application is submitted to Ohio EPA.

E. Authorization

1. Obtaining authorization to discharge. Operators that discharge stormwater associated

with construction activity must submit an NOI application form and Stormwater Pollution

Prevention Plan (SWP3) if located within the Big Darby Creek watershed or portions of

the Olentangy watershed in accordance with the requirements of Part I.F of this permit to

obtain authorization to discharge under this general permit. As required under OAC

Rule 3745-38-02(E), the director, in response to the NOI submission, will notify the

applicant in writing that he/she has or has not been granted general permit coverage to

discharge stormwater associated with construction activity under the terms and

conditions of this permit or that the applicant must apply for an individual NPDES permit

or coverage under an alternate general NPDES permit as described in Part I.C.1.

2. No release from other requirements. No condition of this permit shall release the

permittee from any responsibility or requirements under other environmental statutes or

Page 7 of 61

Ohio EPA Permit No.: OHC000006

regulations. Other permit requirements commonly associated with construction activities

include, but are not limited to, section 401 water quality certifications, isolated wetland

permits, permits to install sanitary sewers or other devices that discharge or convey

polluted water, permits to install drinking water lines, single lot sanitary system permits

and disturbance of land which was used to operate a solid or hazardous waste facility

(i.e., coverage under this NPDES general permit does not satisfy the requirements of

OAC Rule 3745-27-13 or ORC Section 3734.02(H)). The issuance of this permit is

subject to resolution of an antidegradation review. This permit does not relieve the

permittee of other responsibilities associated with construction activities such as

contacting the Ohio Department of Natural Resources, Division of Water, to ensure

proper well installation and abandonment of wells.

F. Notice of Intent Requirements

1. Deadlines for notification.

a. Initial coverage: Operators who intend to obtain initial coverage for a stormwater

discharge associated with construction activity under this general permit must submit

a complete and accurate NOI application form, a completed Stormwater Pollution

Prevention Plan (SWP3) for projects within the Big Darby Creek and portions of the

Olentangy river watersheds and appropriate fee at least 21 days (or 45 days in the

Big Darby Creek watershed and portions of the Olentangy watershed) prior to the

commencement of construction activity. If more than one operator, as defined in

Part VII of this general permit, will be engaged at a site, each operator shall seek

coverage under this general permit prior to engaging in construction activities.

Coverage under this permit is not effective until an approval letter granting coverage

from the director of Ohio EPA is received by the applicant. Where one operator has

already submitted an NOI prior to other operator(s) being identified, the additional

operator shall request modification of coverage to become a co-permittee. In such

instances, the co-permittees shall be covered under the same facility permit number.

No additional permit fee is required.

b. Individual lot transfer of coverage: Operators must each submit an individual lot

notice of intent (Individual Lot NOI) application form (no fee required) to Ohio EPA at

least seven days prior to the date that they intend to accept responsibility for permit

requirements for their portion of the original permitted development from the previous

permittee. Transfer of permit coverage is not granted until an approval letter from the

director of Ohio EPA is received by the applicant.

2. Failure to notify. Operators who fail to notify the director of their intent to be covered and

who discharge pollutants to surface waters of the state without an NPDES permit are in

violation of ORC Chapter 6111. In such instances, Ohio EPA may bring an enforcement

action for any discharges of stormwater associated with construction activity.

3. How to submit an NOI. Operators seeking coverage under this permit must submit a

complete and accurate Notice of Intent (NOI) application using Ohio EPA’s electronic

application form which is available through the Ohio EPA eBusiness Center at:

https://ebiz.epa.ohio.gov/. Submission through the Ohio EPA eBusiness Center will

require establishing an Ohio EPA eBusiness Center account and obtaining a unique

Personal Identification Number (PIN) for final submission of the NOI. Existing eBusiness

Page 8 of 61

Ohio EPA Permit No.: OHC000006

Center account holders can access the NOI form through their existing account and

submit using their existing PIN. Please see the following link for guidance:

https://epa.ohio.gov/divisions-and-offices/surface-water/permitting/electronic-

business-services-sub/streams. Alternatively, if you are unable to access the NOI

form through the agency eBusiness Center due to a demonstrated hardship, the NOI

may be submitted on a paper NOI form provided by Ohio EPA. NOI information shall be

typed on the form. Please contact Ohio EPA, Division of Surface Water at (614) 644-

2001 if you wish to receive a paper NOI form.

4. Additional notification. NOIs and SWP3s are considered public documents and shall be

made available to the public in accordance with Part III.C.2. The permittee shall make

NOIs and SWP3s available upon request of the director of Ohio EPA, local agencies

approving sediment and erosion control plans, grading plans or stormwater management

plans, local governmental officials, or operators of municipal separate storm sewer

systems (MS4s) receiving drainage from the permitted site. Each operator that

discharges to an NPDES permitted MS4 shall provide a copy of its Ohio EPA NOI

submission to the MS4 in accordance with the MS4’s requirements, if applicable.

5. Re-notification. Existing permittees having coverage under the previous generation of

this general permit shall have continuing coverage under OHC000006 with the submittal

of a timely renewal application. Within 180 days from the effective date of this permit,

existing permittees shall submit the completed renewal application expressing their

intent for continued coverage. In accordance with Ohio Administrative Code (OAC)

3745-38-02(E)(2)(a)(ii), a renewal application fee will not apply to existing permittees

having general permit coverage issued on or after April 22, 2022. Permit coverage will

be terminated if Ohio EPA does not receive the renewal application within this 180-day

period.

Part II. NON-NUMERIC EFFLUENT LIMITATIONS

You shall comply with the following non-numeric effluent limitations for discharges from your site

and/or from construction support activities. Part III of this permit contains the specific design

criteria to meet the objectives of the following non-numeric effluent limitations. You shall

develop and implement the SWP3 in accordance with Part III of this permit to satisfy these non-

numeric effluent limitations.

A. Erosion and Sediment Controls. You shall design, install and maintain effective

erosion controls and sediment controls to minimize the discharge of pollutants. At a

minimum, such controls shall be designed, installed and maintained to:

1. Control stormwater volume and velocity within the site to minimize soil and stream

erosion;

2. Control stormwater discharges, including both peak flowrates and total stormwater

volume, to minimize erosion at outlets and to minimize downstream channel and

streambank erosion;

3. Minimize the amount of soil exposed during construction activity;

4. Minimize the disturbance of steep slopes;

Page 9 of 61

Ohio EPA Permit No.: OHC000006

5. Minimize sediment discharges from the site. The design, installation and maintenance

of erosion and sediment controls shall address factors such as the amount, frequency,

intensity and duration of precipitation, the nature of resulting stormwater runoff, and soil

characteristics, including the range of soil particle sizes expected to be present on the

site;

6. If feasible, provide and maintain a 50-foot undisturbed natural buffer around surface

waters of the state, direct stormwater to vegetated areas to increase sediment removal

and maximize stormwater infiltration. If it is infeasible to provide and maintain an

undisturbed 50-foot natural buffer, you shall comply with the stabilization requirements

found in Part II.B for areas within 50 feet of a surface water; and

7. Minimize soil compaction and, unless infeasible, preserve topsoil.

B. Soil Stabilization. Stabilization of disturbed areas shall, at a minimum, be initiated in

accordance with the time frames specified in the following tables.

Table 1: Permanent Stabilization

Area requiring permanent stabilization

Time frame to apply erosion controls

Any areas that will lie dormant for one year or

Within seven days of the most recent

disturbance

Any areas within 50 feet of a surface water of

the state and at final grade

Within two days of reaching final grade

Other areas at final grade

Within seven days of reaching final grade

within that area

Table 2: Temporary Stabilization

Area requiring temporary stabilization

Time frame to apply erosion controls

Any disturbed areas within 50 feet of a

surface water of the state and not at final

grade

Within two days of the most recent

disturbance if the area will remain idle for

more than 14 days

Any disturbed areas that will be dormant for

more than 14 days but less than one year,

and not within 50 feet of a surface water of

the state

Within seven days of the most recent

disturbance within the area

For residential subdivisions, disturbed areas

must be stabilized at least seven days prior to

transfer of permit coverage for the individual

lot(s).

Disturbed areas that will be idle over winter

Prior to the onset of winter weather

Where vegetative stabilization techniques may cause structural instability or are

otherwise unobtainable, alternative stabilization techniques must be employed.

Permanent and temporary stabilization are defined in Part VII.

C. Dewatering. Discharges from dewatering activities, including discharges from

dewatering of trenches and excavations, are prohibited unless managed by appropriate

controls.

Page 10 of 61

Ohio EPA Permit No.: OHC000006

D. Pollution Prevention Measures. Design, install, implement and maintain effective

pollution prevention measures to minimize the discharge of pollutants. At a minimum,

such measures must be designed, installed, implemented and maintained to:

1. Minimize the discharge of pollutants from equipment and vehicle washing, wheel

washwater, and other washwaters. Washwaters shall be treated in a sediment basin or

alternative control that provides equivalent or better treatment prior to discharge;

2. Minimize the exposure of construction materials, products, and wastes; landscape

materials, fertilizers, pesticides, and herbicides; detergents, sanitary waste and other

materials present on the site to precipitation and to stormwater; and

3. Minimize the discharge of pollutants from spills and leaks and implement chemical spill

and leak prevention and response procedures.

E. Prohibited Discharges. The following discharges are prohibited:

1. Wastewater from washout of concrete, unless managed by an appropriate control;

2. Wastewater from washout and cleanout of stucco, paint, form release oils, curing

compounds and other construction materials;

3. Fuels, oils, or other pollutants used in vehicle and equipment operation and

maintenance; and

4. Soaps or solvents used in vehicle and equipment washing or all other waste water

streams which could be subject to an individual NPDES permit (Part III.G.2.g).

F. Surface Outlets. When discharging from sediment basins utilize outlet structures that

withdraw water from the surface, unless infeasible. (Note: Ohio EPA believes that the

circumstances in which it is infeasible to design outlet structures in this manner are rare.

Exceptions may include time periods with extended cold weather during winter months.

If you have determined that it is infeasible to meet this requirement, you shall provide

documentation in your SWP3 to support your determination.)

G. Post-Construction Stormwater Management Controls. So that receiving stream’s

physical, chemical and biological characteristics are protected, and stream functions are

maintained, post-construction stormwater practices shall provide long-term management

of runoff quality and quantity.

PART III. STORMWATER POLLUTION PREVENTION PLAN (SWP3)

A. Stormwater Pollution Prevention Plans.

A SWP3 shall be developed for each site covered by this permit. For a multi-phase construction

project, a separate NOI shall be submitted when a separate SWP3 will be prepared for

subsequent phases. SWP3s shall be prepared in accordance with sound engineering and/or

conservation practices by a professional experienced in the design and implementation of

standard erosion and sediment controls and stormwater management practices addressing all

phases of construction. The SWP3 shall clearly identify all activities which are required to be

Page 11 of 61

Ohio EPA Permit No.: OHC000006

authorized under Section 401 and subject to an antidegradation review. The SWP3 shall identify

potential sources of pollution which may reasonably be expected to affect the quality of

stormwater discharges associated with construction activities. The SWP3 shall be a

comprehensive, stand-alone document, which is not complete unless it contains the information

required by Part III.G of this permit. In addition, the SWP3 shall describe and ensure the

implementation of best management practices (BMPs) that reduce the pollutants and impact of

stormwater discharges during construction and pollutants associated with the post-construction

land use to ensure compliance with ORC Section 6111.04, OAC Chapter 3745-1 and the terms

and conditions of this permit.

B. Timing.

An acceptable SWP3 shall be completed and submitted to the applicable regulated MS4

entity (for projects constructed entirely within a regulated MS4 area) prior to the timely

submittal of an NOI. Projects within the Big Darby Creek and portions of the Olentangy

watersheds must submit a SWP3 with the NOI. The SWP3 shall be updated in accordance

with Part III.D. Submission of a SWP3 does not constitute review and approval on the part of

Ohio EPA. Upon request and good cause shown, the director may waive the requirement to

have a SWP3 completed at the time of NOI submission. If a waiver has been granted, the

SWP3 must be completed prior to the initiation of construction activities. The SWP3 must be

implemented upon initiation of construction activities.

In order to continue coverage from the previous generations of this permit, the permittee shall

review and update the SWP3 to ensure that this permit’s requirements are addressed within 180

days after the effective date of this permit. If it is infeasible for you to comply with a specific

requirement in this permit because (1) the provision was not part of the permit you were

previously covered under, and (2) because you are prevented from compliance due to the

nature or location of earth disturbances that commenced prior to the effective date of this

permit, you shall include documentation within your SWP3 of the reasons why it is infeasible for

you to meet the specific requirement.

Examples of OHC000006 permit conditions that would be infeasible for permittees renewing

coverage to comply with include:

• OHC000006 post-construction requirements, for projects that obtained NPDES

construction stormwater coverage and started construction activities prior to the effective

date of this permit;

• OHC000006 post-construction requirements, for multi-phase development projects with an

existing regional post-construction BMP issued under previous NPDES post-construction

requirements. This only applies to construction sites authorized under Ohio EPA’s

Construction Stormwater Permits issued after April 20, 2003; or

• Case-by-case situations approved by the Director.

C. SWP3 Signature and Review.

1. Plan Signature and Retention On-Site. The SWP3 shall include the certification in Part

V.H, be signed in accordance with Part V.G., and be retained on site during working

hours.

Page 12 of 61

Ohio EPA Permit No.: OHC000006

2. Plan Availability

a. On-site: The plan shall be made available immediately upon request of the director

or his authorized representative and MS4 operators or their authorized

representative during working hours. A copy of the NOI and letter granting permit

coverage under this general permit also shall be made available at the site. The NOI

and letter granting permit coverage may be maintained electronically under the

condition that they can be immediately produced on-site upon request. The SWP3

may be prepared, signed, and kept electronically, rather than in paper form, if the

records are: (a) in a format that can be read in a similar manner as a paper record;

(b) legally dependable with no less evidentiary value than their paper equivalent; and

as a paper copy stored at the site would be, if the records were stored in paper form.

For additional guidance on the proper practices to follow for the electronic retention

of inspection report records, refer to this general permit’s Fact Sheet at

https://epa.ohio.gov/divisions-and-offices/surface-water/permitting/storm-water-

discharges-from-small-and-large-construction-activities--general-permit

b. By written request: The permittee must provide the most recent copy of the SWP3

within 7 days upon written request by any of the following:

i. The director or the director’s authorized representative;

ii. A local agency approving sediment and erosion plans, grading plans or

stormwater management plans; or

iii. In the case of a stormwater discharge associated with construction activity which

discharges through a municipal separate storm sewer system with an NPDES

permit, to the operator of the system.

c. To the public: All NOIs, general permit approval for coverage letters, and SWP3s

are considered reports that shall be available to the public in accordance with the

Ohio Public Records law. The permittee shall make documents available to the

public upon request or provide a copy at public expense, at cost, in a timely manner.

However, the permittee may claim to Ohio EPA any portion of an SWP3 as

confidential in accordance with Ohio law.

3. Plan Revision. The director or authorized representative may notify the permittee at any

time that the SWP3 does not meet one or more of the minimum requirements of this

part. Within 10 days after such notification from the director or authorized representative

(or as otherwise provided in the notification), the permittee shall make the required

changes to the SWP3 and shall submit to Ohio EPA the revised SWP3 or a written

certification that the requested changes have been made.

D. Amendments.

The permittee shall amend the SWP3 whenever there is a change in design, construction,

operation or maintenance, which has a significant effect on the potential for the discharge of

pollutants to surface waters of the state or if the SWP3 proves to be ineffective in achieving the

general objectives of controlling pollutants in stormwater discharges associated with

Page 13 of 61

Ohio EPA Permit No.: OHC000006

construction activity. Amendments to the SWP3 may be reviewed by Ohio EPA in the same

manner as Part III.C.

E. Duty to inform contractors and subcontractors.

The permittee shall inform all contractors and subcontractors not otherwise defined as

“operators” in Part VII of this general permit who will be involved in the implementation of the

SWP3 of the terms and conditions of this general permit. The permittee shall maintain a written

document containing the signatures of all contractors and subcontractors involved in the

implementation of the SWP3 as proof acknowledging that they reviewed and understand the

conditions and responsibilities of the SWP3. For contactors and subcontractors which do not

meet the definition of an operator, the written document shall be created and signatures shall be

obtained prior to commencement of each contractors/subcontractors work.

F. Total Maximum Daily Load (TMDL) allocations.

If a TMDL is approved for any waterbody into which the permittee’s site discharges and requires

specific BMPs for construction sites, the director may require the permittee to revise his/her

SWP3. Specific conditions have been provided in Appendix A (for the Big Darby Creek

Watershed) and Appendix B (for portions of the Olentangy river watershed).

G. SWP3 Requirements.

Operations that discharge stormwater from construction activities are subject to the following

requirements and the SWP3 shall include the following items:

1. Site description. Each SWP3 shall provide:

a. A description of the nature and type of the construction activity (e.g., low density

residential, shopping mall, highway, etc.);

b. Total area of the site and the area of the site that is expected to be disturbed

(i.e., grubbing, clearing, excavation, filling or grading, including off-site borrow

areas);

c. A measure of the impervious area and percent imperviousness created by the

construction activity (existing, new and total impervious area after construction);

d. Stormwater calculations, including the volumetric runoff coefficients for both the

pre-construction and post- construction site conditions, and resulting water

quality volume; design details for post-construction stormwater facilities and

pretreatment practices such as contributing drainage areas, capacities,

elevations, outlet details and drain times shall be included in the SWP3; and if

applicable, explanation of the use of existing post-construction facilities. Ohio

EPA recommends the use of data sheets (see Ohio’s Rainwater and Land

Development manual and Ohio EPA resources for examples);

e. Existing data describing the soil and, if available, the quality of any discharge

from the site;

Page 14 of 61

Ohio EPA Permit No.: OHC000006

f. A description of prior land uses at the site;

g. A description of the condition of any on-site streams (e.g. prior channelization,

bed instability or headcuts, channels on public maintenance, or natural

channels);

h. A BMP implementation schedule which describes the sequence of major

construction operations (i.e., designation of vegetative preservation areas,

grubbing, excavating, grading, utilities, infrastructure installation and others) and

the implementation of erosion, sediment and stormwater management practices

or facilities to be employed during each operation of the sequence;

i. The name and/or location of the immediate receiving stream or surface water(s)

and the first subsequent named receiving water(s) and the areal extent and

description of wetlands or other special aquatic sites at or near the site which will

be disturbed, or which will receive discharges from disturbed areas of the project.

For discharges to an MS4, the point of discharge to the MS4 and the location

where the MS4 ultimately discharges to a stream or surface water of the state

shall be indicated;

j. For subdivided developments, a detail drawing of individual parcels with their

erosion, sediment or stormwater control practices and/or a typical individual lot

showing standard individual lot erosion and sediment control practices.

A typical individual lot drawing does not remove the responsibility to designate

specific erosion and sediment control practices in the SWP3 for critical areas

such as steep slopes, stream banks, drainage ways and riparian zones;

k. Location and description of any stormwater discharges associated with dedicated

asphalt and dedicated concrete plants covered by this permit and the best

management practices to address pollutants in these stormwater discharges;

l. A cover page or title identifying the name and location of the site, the name and

contact information of all construction site operators, the name and contact

information for the person responsible for authorizing and amending the SWP3,

preparation date, and the estimated dates that construction will start and be

complete;

m. A log documenting grading and stabilization activities as well as amendments to

the SWP3, which occur after construction activities commence; and

n. Site map showing:

i. Limits of earth-disturbing activity of the site including associated off-site

borrow or spoil areas that are not addressed by a separate NOI and

associated SWP3;

ii. Soils types for all areas of the site, including locations of unstable or

highly erodible and/or known contaminated soils;

Page 15 of 61

Ohio EPA Permit No.: OHC000006

iii. Existing and proposed contours. A delineation of drainage watersheds

expected during and after major grading activities as well as the size of

each drainage watershed, in acres;

iv. The location of any delineated boundary for required riparian setbacks;

v. Conservation easements or areas designated as open space, preserved

vegetation or otherwise protected from earth disturbing activities. A

description of any associated temporary or permanent fencing or signage;

vi. Surface water locations including springs, wetlands, streams, lakes, water

wells, etc., on or within 200 feet of the site, including the boundaries of

wetlands or stream channels and first subsequent named receiving

water(s) the permittee intends to fill or relocate for which the permittee is

seeking approval from the Army Corps of Engineers and/or Ohio EPA;

vii. Existing and planned locations of buildings, roads, parking facilities and

utilities;

viii. The location of all erosion and sediment control practices, including the

location of areas likely to require temporary stabilization during site

development;

ix. Sediment traps and basins noting their sediment storage and dewatering

(detention) volume and contributing drainage area. Ohio EPA

recommends the use of data sheets (see Ohio EPA’s Rainwater and

Land Development manual and website for examples) to provide data for

all sediment traps and basins noting important inputs to design and

resulting parameters such as their contributing drainage area, disturbed

area, detention volume, sediment storage volume, practice surface area,

dewatering time, outlet type and dimensions;

x. The location of permanent stormwater management practices (new and

existing) including pretreatment practices to be used to control pollutants

in stormwater after construction operations have been completed along

with the location of existing and planned drainage features including catch

basins, culverts, ditches, swales, surface inlets and outlet structures;

xi. Areas designated for the storage or disposal of solid, sanitary and toxic

wastes, including dumpster areas, areas designated for cement truck

washout, and vehicle fueling;

xii. The location of designated construction entrances where the vehicles will

access the construction site; and

xiii. The location of any areas of proposed floodplain fill, floodplain

excavation, stream restoration or known temporary or permanent stream

crossings.

Page 16 of 61

Ohio EPA Permit No.: OHC000006

2. Controls. In accordance with Part II.A, the SWP3 shall contain a description of the

controls appropriate for each construction operation covered by this permit and the

operator(s) shall implement such controls. The SWP3 shall clearly describe for each

major construction activity identified in Part III.G.1.h: (a) appropriate control measures

and the general timing (or sequence) during the construction process that the measures

will be implemented; and (b) which contractor is responsible for implementation (e.g.,

contractor A will clear land and install perimeter controls and contractor B will maintain

perimeter controls until final stabilization). The SWP3 shall identify the subcontractors

engaged in activities that could impact stormwater runoff. The SWP3 shall contain

signatures from all of the identified subcontractors indicating that they have been

informed and understand their roles and responsibilities in complying with the SWP3.

Ohio EPA recommends that the primary site operator review the SWP3 with the primary

contractor prior to commencement of construction activities and keep a SWP3 training

log to demonstrate that this review has occurred.

Ohio EPA recommends that the erosion, sediment, and stormwater management

practices used to satisfy the conditions of this permit should meet the standards and

specifications in the most current edition of Ohio’s Rainwater and Land Development

(see definitions) manual or other standards acceptable to Ohio EPA. The controls shall

include the following minimum components:

a. Preservation Methods. The SWP3 shall make use of practices which preserve

the existing natural condition as much as feasible. Such practices may include:

preserving existing vegetation, vegetative buffer strips, and existing soil profile

and topsoil; phasing of construction operations to minimize the amount of

disturbed land at any one time; and designation of tree preservation areas or

other protective clearing or grubbing practices. For all construction activities

immediately adjacent to surface waters of the state, the permittee shall comply

with the buffer non-numeric effluent limitation in Part II.A.6, as measured from the

ordinary high water mark of the surface water. Ohio EPA strongly recommends

that 50-foot buffers be maintained around surface waters, including wetlands.

b. Erosion Control Practices. The SWP3 shall make use of erosion controls that

provide cover over disturbed soils unless an exception is approved in accordance

with Part III.G.4. A description of control practices designed to re-establish

vegetation or suitable cover on disturbed areas after grading shall be included in

the SWP3. The SWP3 shall provide specifications for stabilization of all

disturbed areas of the site and provide guidance as to which method of

stabilization will be employed for any time of the year. Such practices may

include: temporary seeding, permanent seeding, mulching, matting, sod

stabilization, vegetative buffer strips, phasing of construction operations, use of

construction entrances and the use of alternative ground cover.

i. Stabilization. Disturbed areas shall be stabilized in accordance with

Table 1 (Permanent Stabilization) and Table 2 (Temporary Stabilization)

in Part II.B of this permit.

ii. Permanent stabilization of conveyance channels. Operators shall

undertake special measures to stabilize channels and outfalls and

prevent erosive flows. Measures may include seeding, dormant seeding

Page 17 of 61

Ohio EPA Permit No.: OHC000006

(as defined in the most current edition of the Rainwater and Land

Development manual), mulching, erosion control matting, sodding, riprap,

natural channel design with bioengineering techniques or rock check

dams.

c. Runoff Control Practices. The SWP3 shall incorporate measures which control

the flow of runoff from disturbed areas so as to prevent erosion from occurring.

Such practices may include rock check dams, pipe slope drains, diversions to

direct flow away from exposed soils and protective grading practices. These

practices shall divert runoff away from disturbed areas and steep slopes where

practicable. Velocity dissipation devices shall be placed at discharge locations

and along the length of any outfall channel to provide non-erosive flow velocity

from the structure to a water course so that the natural physical and biological

characteristics and functions are maintained and protected.

d. Sediment Control Practices. The plan shall include a description of structural

practices that shall store runoff allowing sediments to settle and/or divert flows

away from exposed soils or otherwise limit runoff from exposed areas. Structural

practices shall be used to control erosion and trap sediment from a site

remaining disturbed for more than 14 days. Such practices may include, among

others: sediment settling ponds, sediment barriers, earth diversion dikes or

channels which direct runoff to a sediment settling pond and storm drain inlet

protection. All sediment control practices must be capable of ponding runoff in

order to be considered functional. Earth diversion dikes or channels alone are

not considered a sediment control practice unless those are used in conjunction

with a sediment settling pond.

The SWP3 shall contain detail drawings for all structural practices.

i. Timing. Sediment control structures shall be functional throughout the

course of earth disturbing activity. Sediment basins and perimeter

sediment barriers shall be implemented prior to grading and within seven

days from the start of grubbing. They shall continue to function until the

upslope development area is stabilized with permanent cover. As

construction progresses and the topography is altered, appropriate

controls shall be constructed, or existing controls altered to address the

changing drainage patterns.

ii. Sediment settling ponds. A sediment settling pond is required for any

one of the following conditions:

• Concentrated or collected stormwater runoff (e.g., storm sewer or

ditch);

• Runoff from drainage areas, which exceed the design capacity of silt

fence or other sediment barriers; or

• Runoff from drainage areas that exceed the design capacity of inlet

protection.

The permittee may request approval from Ohio EPA to use alternative

controls if the permittee can demonstrate the alternative controls are

equivalent in effectiveness to a sediment settling pond.

Page 18 of 61

Ohio EPA Permit No.: OHC000006

In accordance with Part II.F, if feasible, sediment settling ponds shall be

dewatered at the pond surface using a skimmer or equivalent device.

The sediment settling pond volume consists of both a dewatering zone

and a sediment storage zone. The volume of the dewatering zone shall

be a minimum of 1800 cubic feet (ft

) per acre of drainage (67 yd

/acre)

with a minimum 48-hour drain time. The volume of the sediment storage

zone shall be calculated by one of the following methods:

Method 1: The volume of the sediment storage zone shall be 1000 ft

per

disturbed acre within the watershed of the basin. OR

Method 2: The volume of the sediment storage zone shall be the volume

necessary to store the sediment as calculated with RUSLE or a similar

generally accepted erosion prediction model.

Accumulated sediment shall be removed from the sediment storage zone

once it exceeds 50 percent of the minimum required sediment storage

design capacity and prior to the conversion to the post-construction

practice unless suitable storage is demonstrated based upon over-design.

When determining the total contributing drainage area, off-site areas and

areas which remain undisturbed by construction activity shall be included

unless runoff from these areas is diverted away from the sediment settling

pond and is not co-mingled with sediment-laden runoff. The depth of the

dewatering zone shall be less than or equal to five feet. The configuration

between inlets and the outlet of the basin shall provide at least two units

of length for each one unit of width (≥ 2:1 length:width ratio); however, a

length to width ratio of 4:1 is recommended. When designing sediment

settling ponds, the permittee shall consider public safety, especially as it

relates to children, as a design factor for the sediment basin and

alternative sediment controls shall be used where site limitations would

preclude a safe design. Combining multiple sediment and erosion control

measures in order to maximize pollutant removal is encouraged.

iii. Sediment Barriers and Diversions. Sheet flow runoff from denuded

areas shall be intercepted by sediment barriers or diverted to a sediment

pond to protect adjacent properties and water resources from sediment

transported via sheet flow. Where intended to provide sediment control,

sediment barriers shall be placed on a level contour downslope of the

disturbed area. For most applications, standard silt fence or a 12-inch

diameter tubular filter may be used as a sediment barrier. The

relationship between the maximum drainage area to sediment barrier for

a particular slope range is shown in the following table:

Table 3 Sediment Barrier Maximum Drainage Area Based on Slope

Maximum drainage area (in acres) to 100

linear feet of sediment barrier

Range of slope for a particular

drainage area (in percent)

0.5

< 2%

0.25

> 2% but < 20%

0.125

> 20% but < 50%

Page 19 of 61

Ohio EPA Permit No.: OHC000006

Placing sediment barriers in a parallel series does not extend the size of

the drainage area. Stormwater diversion practices shall be used to keep

runoff away from disturbed areas and steep slopes where practicable.

Diversion practices, which include swales, dikes or berms, may receive

stormwater runoff from areas up to 10 acres.

iv. Inlet Protection. Other erosion and sediment control practices shall

minimize sediment laden water entering active storm drain systems. All

inlets receiving runoff from drainage areas of one or more acres will

require a sediment settling pond.

v. Surface Waters of the State Protection. If construction activities disturb

areas adjacent to surface waters of the state, structural practices shall be

designed and implemented on site to protect all adjacent surface waters

of the state from the impacts of sediment runoff. No structural sediment

controls (e.g., the installation of silt fence or a sediment settling pond)

shall be used in a surface water of the state. For all construction activities

immediately adjacent to surface waters of the state, the permittee shall

comply with the buffer non-numeric effluent limitation in Part II.A.6, as

measured from the ordinary high water mark of the surface water. Where

impacts within this buffer area are unavoidable, due to the nature of the

construction (e.g., stream crossings for roads or utilities), the project shall

be designed such that the number of stream crossings and the width of

the disturbance within the buffer area are minimized.

vi. Modifying Controls. If periodic inspections or other information

indicates a control has been used inappropriately or incorrectly, the

permittee shall replace or modify the control for site conditions.

e. Post-Construction Stormwater Management Requirements. So that receiving

stream’s physical, chemical and biological characteristics are protected, and

stream functions are maintained, post-construction stormwater practices shall

provide long-term management of runoff quality and quantity. To meet the post-

construction requirements of this permit, the SWP3 shall contain a description of

the post-construction BMPs that will be installed during construction for the site

and the rationale for their selection. The rationale shall address the anticipated

impacts on the channel and floodplain morphology, hydrology, and water quality.

Post-construction BMPs cannot be installed within a surface water of the state

(e.g., wetland or stream) unless it is authorized by a CWA 401 water quality

certification, CWA 404 permit, or Ohio EPA non-jurisdictional wetland/stream

program approval. Note: local jurisdictions may have more stringent post-

construction requirements.

i. Operation and Maintenance Plans. Detail drawings and maintenance

plans shall be provided for all post-construction BMPs in the SWP3.

Maintenance plans shall be provided by the permittee to the post-

construction operator of the site (including homeowner associations) upon

completion of construction activities (prior to termination of permit

coverage). Maintenance plans shall ensure that pollutants collected within

structural post-construction practices are disposed of in accordance with

Page 20 of 61

Ohio EPA Permit No.: OHC000006

local, state, and federal regulations. To ensure that stormwater

management systems function as designed and constructed, the post-

construction operation and maintenance plan shall be a stand-alone

document which contains:

1) a designated entity for stormwater inspection and maintenance

responsibilities;

2) the routine and non-routine maintenance tasks to be undertaken;

3) a schedule for inspection and maintenance;

4) any necessary legally binding maintenance easements and

agreements;

5) construction drawings or excerpts showing the plan view, profile

and details of the outlet(s);

6) a map showing all access and maintenance easements; and

7) for table 4a/4b practices, provide relevant elevations and

associated volumes that dictate when removal of accumulated

sediments must occur.

Permittees are responsible for assuring all post-construction practices

meet plan specifications and intended post-construction conditions have

been met (e.g., sediment removed from, and sediment storage restored

to, permanent pools, sediment control outlets removed and replaced with

permanent post-construction discharge structures, and all slopes and

drainageways permanently stabilized), but are not responsible under this

permit for operation and maintenance of post-construction practices once

coverage under this permit is terminated.

ii. Point Source Dischargers. Post-construction stormwater BMPs that

discharge pollutants from point sources once construction is completed

may in themselves need authorization under a separate NPDES permit

(one example is stormwater discharges from regulated industrial sites).

iii. No Impervious Surface. Construction activities that do not include the

installation of any impervious surface (e.g., park lands), abandoned mine

land reclamation activities regulated by the Ohio Department of Natural

Resources, stream and wetland restoration activities, and wetland

mitigation activities are not required to comply with the conditions of Part

III.G.2.e of this permit. Linear construction projects (e.g., pipeline or utility

line installation) which do not result in the installation of additional

impervious surface are not required to comply with the conditions of Part

III.G.2.e of this permit. However, linear construction projects shall be

designed to minimize the number of stream crossings and the width of

disturbance, and to achieve final stabilization of the disturbed area as

defined in Part VII.M.1.

iv. Post-Construction BMPs. For all construction activities that will disturb

two or more acres of land or will disturb less than two acres that are part

of a larger common plan of development or sale which will disturb two or

more acres of land, the post construction BMP(s) chosen shall be able to

manage stormwater runoff for protection of stream channels, stream

stability, and water quality. The BMP(s) chosen must be compatible with

Page 21 of 61

Ohio EPA Permit No.: OHC000006

site and soil conditions. Structural post-construction stormwater

treatment practices shall be incorporated into the permanent drainage

system for the site. The BMP(s) chosen must be sized to treat the water

quality volume (WQ

) and ensure compliance with Ohio’s Water Quality

Standards in OAC Chapter 3745-1. The WQ

shall be equivalent to the

volume of runoff from a 0.90-inch rainfall and shall be determined using

the following equations:

= Rv * P * A / 12 (Equation 1)

where:

= water quality volume in acre-feet

Rv = the volumetric runoff coefficient calculated using equation 2

P = 0.90 inch precipitation depth

A = area draining into the BMP in acres

Rv = 0.05 + 0.9i (Equation 2)

where i = fraction of post-construction impervious surface

Ohio EPA recommends BMPs be designed according to the methodology

described in the most current edition of the Rainwater and Land

Development manual or in another design manual acceptable for use by

Ohio EPA and in accordance with ORC Chapter 4733.

The BMPs listed in Tables 4a and 4b below are considered standard

BMPs approved for general use. However, communities with a regulated

MS4 may limit the use of some of these BMPs. BMPs shall be designed

such that the drain time is long enough to provide treatment but short

enough to provide storage for successive rainfall events and avoid the

creation of nuisance conditions. The outlet structure for the post-

construction BMP shall not discharge more than the first half of the WQv

in less than one-third of the minimum drain time listed in Table 4a. The

WQv is the volume of stormwater runoff that must be detained by a post-

construction practice as specified by the most recent edition of the

Rainwater and Land Development manual.

Post-construction practices shall be sized to treat 100% of the WQv

associated with their contributing drainage area. If there is an existing

post-construction BMP that treats runoff from the disturbed area and the

BMP meets the post-construction requirements of this permit, no

additional post-construction BMP will be required. A regional stormwater

BMP may be used to meet the post-construction requirement if: (1) the

BMP meets the design requirements for treating the WQv; and (2) a legal

agreement is established through which the regional BMP owner or

operator agrees to provide this service in the long term. Design

information for such facilities such as contributing drainage areas,

capacities, elevations, outlet details and drain times shall be included in

the SWP3.

Page 22 of 61

Ohio EPA Permit No.: OHC000006

Table 4a Extended Detention Post-Construction Practices with Minimum Drain Times

Extended Detention Practices

Minimum Drain Time of WQv

Wet Extended Detention Basin

1,2,3

24 hours

Extended Detention Constructed Wetland

1, 3

24 hours

Dry Extended Detention Basin with Forebay and

Micropool

1,3,4

48 hours

Permeable Pavement – Extended Detention

24 hours

Underground Storage Facility– Extended Detention

1,5

24 hours

Sand Filter - Extended Detention

1, 6

24 hours

Notes:

1. The outlet structure shall not discharge more than the first half of the WQv in less than

one-third of the minimum drain time.

2. Provide a permanent pool with a minimum volume equal to the WQv and an extended

detention volume above the permanent pool equal to the WQv.

3. An additional volume equal to 20 percent of the WQ

shall be incorporated into the

BMP for sediment storage.

4. Dry extended detention basins must include a forebay and a micropool each sized at a

minimum of 0.1 x WQv and a protected outlet, or include acceptable pretreatment and a

protected outlet.

5. Underground storage must have pretreatment for removal of suspended sediments

included in the design and documented in the SWP3. This pretreatment shall concentrate

sediment in a location where it can be readily removed. For non-infiltrating, underground

extended detention systems, pretreatment shall be at least 50% effective at capturing

total suspended solids according to the testing protocol established in the Alternative

Post-Construction BMP Testing Protocol.

6. The WQv ponding area shall completely empty between 24 and 72 hours.

Table 4b Infiltration Post-Construction Practices with Maximum Drain Times

Infiltration Practices

Maximum Drain Time of WQv

Bioretention

1,2,3

24 hours

Infiltration Basin

2,3

24 hours

Infiltration Trench

3,4

48 hours

Permeable Pavement – Infiltration

48 hours

Underground Storage Facility – Infiltration

3,4,5

48 hours

Notes:

1. Bioretention soil media shall have a permeability of approximately 1 – 5 in/hr. Meeting

the soil media specifications in the Rainwater and Land Development manual is

considered compliant with this requirement. Bioretention cells must have underdrains

unless in-situ conditions allow for the WQv (surface ponding) plus the bioretention soil (to

a depth of 24 inches) to drain completely within 48 hours.

2. Infiltrating practices with the WQv stored aboveground (bioretention, infiltration basin)

shall fully drain the WQv within 24 hours to minimize nuisance effects of standing water

and to promote vigorous communities of appropriate vegetation.

3. The SWP3 shall demonstrate the design infiltration rate values are derived from site-

specific measurements obtained through field tests of the in-situ soil for practices

designed to infiltrate the WQv.

4. Subsurface practices designed to fully infiltrate the WQv (infiltration trench, permeable

pavement with infiltration, underground storage with infiltration) shall empty within 48

hours to recover storage for subsequent storm events.

5. Underground storage systems with infiltration must have adequate pretreatment of

suspended sediments included in the design and documented in the SWP3 in order to

minimize clogging of the infiltrating surface. Pretreatment shall concentrate sediment in a

location where it can be readily removed. Examples include media filters situated

Page 23 of 61

Ohio EPA Permit No.: OHC000006

upstream of the storage or other suitable alternative approved by Ohio EPA. For

infiltrating underground systems, pretreatment shall be at least 80% effective at capturing

total suspended solids according to the testing protocol established in the Alternative

Post-Construction BMP Testing Protocol.

v. Small Construction Activities. For all construction activities authorized

under this permit which result in a disturbance less than 2 acres, a post-

construction practice shall be used to treat stormwater runoff for

pollutants and to reduce adverse impacts on receiving waters. The

applicant must provide a justification in the SWP3 why the use of table 4a

and 4b practices or runoff reduction practice are not feasible. The

justification must address limiting factors which would prohibit the project

going forward should table 4a and 4b practices be required. Please note

that practices selected will require approval from the regulated MS4.

vi. Transportation Projects. The construction of new roads and roadway

improvement projects by public entities (i.e., the state, counties,

townships, cities, or villages) and the construction of publicly accessible,

non-vehicular (i.e., pedestrian or shared-use) paths by public entities or

non-governmental, non-profit organizations may implement post-

construction BMPs in compliance with the current version (as of the

effective date of this permit) of the Ohio Department of Transportation’s

“Location and Design Manual, Volume Two Drainage Design” that has

been accepted by Ohio EPA as an alternative to the conditions of this

permit.

vii. Offsite Mitigation of Post-Construction. Ohio EPA may authorize the

offsite mitigation of the post-construction requirements of Part III.G.2.e of

this permit on a case by case basis provided the permittee clearly

demonstrates the BMPs listed in Tables 4a and 4b are not feasible and

the following criteria are met: (1) a maintenance agreement or policy is

established to ensure operations and treatment long-term; (2) the offsite

location discharges to the same HUC-12 watershed unit; and (3) the

mitigation ratio of the WQv is 1.5 to 1 or the WQv at the point of retrofit,

whichever is greater. Requests for offsite mitigation must be received

prior to receipt of the NOI application.

viii. Previously Developed Areas. Ohio EPA encourages the redevelopment of

untreated impervious areas through a reduction of the WQv treatment

requirement. For an untreated previously developed area, one or a

combination of the following two conditions shall be met:

• A 20 percent net reduction of the site’s volumetric runoff coefficient

through impervious area reduction with soil restoration or replacing

impervious roof area with green roof area (for these purposes green

roofs shall be considered pervious surface) or

• Treatment of a portion of the site using a practice meeting Table

4a/4b criteria for which the WQv (see Equation 1) equals or exceeds

the WQv

determined with the following equation:

Page 24 of 61

Ohio EPA Permit No.: OHC000006

WQv

= P * A * [(Rv

*0.2) + (Rv

- Rv

)] / 12 (Equation 3)

where

WQv

= Redevelopment Water Quality Volume in acre-feet

P = 0.90 inches

A = disturbed area in acres

= volumetric runoff coefficient for existing (current site)

conditions within the disturbed area

= volumetric runoff coefficient for proposed (post-construction

site) conditions within the disturbed area

and is located to treat impervious areas most likely to generate the

highest pollutant load, such as parking lots or roadways.

This section does not apply to previous development that was

obligated to obtain CGP coverage and provide management of the

WQv under previous generations of this general permit (i.e., after

April 21, 2003).

ix. Runoff Reduction Practices. The size of structural post-construction

practices used to capture and treat the WQv can be reduced by

incorporating runoff reducing practices into the design of the site’s

drainage system. The approach to calculate and document runoff

reduction is detailed in the Rainwater and Land Development Manual.

BMP-specific runoff reduction volumes are set by specifications in the

Rainwater and Land Development Manual for the following practices:

• Impervious surface disconnection

• Rainwater harvesting

• Bioretention

• Infiltration basin

• Infiltration trench

• Permeable pavement with infiltration

• Underground storage with infiltration

• Grass swale

• Sheet flow to filter strip

• Sheet flow to conservation area

A runoff reduction approach may be used to meet the groundwater

recharge requirements in the Big Darby Creek Watershed. The runoff

reduction practices used for groundwater recharge may be used to

reduce the WQv requirement, see appendix A for details on

groundwater recharge requirements.

In order to promote the implementation of green infrastructure, the

Director may consider the use of runoff reducing practices to demonstrate

compliance with Part III.G.2.e of this permit for areas of the site not

draining into a common drainage system of the site, e.g., sheet flow from

Page 25 of 61

Ohio EPA Permit No.: OHC000006

perimeter areas such as the rear yards of residential lots, low density

development scenarios, or where the permittee can demonstrate that the

intent of pollutant removal and stream protection, as required in Part

III.G.2.e of this permit is being addressed through non-structural post-

construction BMPs based upon review and approval by Ohio EPA.

x. Use of Alternative Post-Construction BMPs. This permit does not

preclude the use of innovative or experimental post-construction

stormwater management technologies. Permittees shall request

approval from Ohio EPA to use alternative post-construction BMPs on a

case-by-case basis. The permittee shall submit an application (form

maintained on the Ohio EPA Website) to Ohio EPA for any proposed

alternative post-construction BMP and secure any approval from Ohio

EPA before permittees submit an NOI for permit coverage. Where the

development project is located within a regulated municipal separate

storm sewer system (MS4) community, the use of an alternative

practice requires pre-approval by the MS4 before submittal of the

application to Ohio EPA. Ohio EPA requires that approvals for

alternative post-construction BMPs are finalized.

To use an alternative post-construction BMP, the permittee must

demonstrate that use of a BMP listed in Tables 4a and 4b is not feasible

and the proposed alternative post-construction BMP meets the following

three criteria:

a. Alternative post-construction BMPs must be capable of providing

sustained, long-term treatment of stormwater. It must be durable and

maintainable in accordance with industry standards.

b. Alternative post-construction BMPs shall previously have been tested

to confirm stormwater treatment efficacy equivalent to those BMPs

listed in Tables 4a and 4b using the protocol described in this permit.

BMP testing may include laboratory testing, field testing, or both. For an

alternative BMP to be acceptable, the test results must demonstrate

that the minimum treatment rate is 80% TSS removal at the design flow

rate for laboratory tested BMP. Field test results must demonstrate the

minimum treatment rate is 80% TSS removal for influent concentrations

equal to or greater than 100 mg/L TSS. If the influent concentration to

the proposed alternative BMP is less than 100 mg/L TSS in the field,

then the BMP must achieve an average effluent concentration less than

or equal to 20 mg/L TSS.

c. The discharge rate from the proposed alternative practice shall be

reduced to prevent stream bed erosion and protect the physical and

biological stream integrity unless there will be negligible hydrological

impact to the receiving surface water of the state. Discharge rate is

considered to have a negligible impact if the permittee can

demonstrate that the entire WQv is recharged to groundwater, the

larger common plan of development or sale will create less than one

acre of impervious surface or the stormwater drainage system of the

Page 26 of 61

Ohio EPA Permit No.: OHC000006

development discharges directly into a large river with drainage area

equal to 100 square miles or larger upstream of the development site

or to a lake where the development area is less than 5 percent of the

watershed area, unless a TMDL has identified water quality problems

into the receiving surface waters of the state. If the conditions above

that minimize the potential for hydrological impact to the receiving

surface water of the state do not exist, then the alternative post-

construction BMP must prevent stream erosion by reducing the flow

rate from the WQV. In such cases, discharge of the WQV must be

controlled. A second stormwater BMP that provides extended

detention of the WQv may be needed to meet the post-construction

criteria.

Alternative BMPs that utilize treatment processes such as filtering or

centrifugal separation, rather than a detention and settling volume,

must be designed to ensure treatment of 90 percent of the average

annual runoff volume. For the design of these BMPs, the water quality

flow rate (WQF) shall be determined utilizing the Rational Method

(Equation 4) with an intensity (i) appropriate for the water quality

precipitation event. This intensity shall be calculated using the table

given in Appendix C.

WQF = C * i * A (Equation 4)

Where

WQF = water quality flow rate in cubic feet per second (cfs)

C = rational method runoff coefficient

i = intensity (in/hr)

A = area draining to the BMP (acres)

xi. Alternative Post-Construction BMP Testing Protocol. For laboratory

testing, the alternative BMP shall be tested using sediment with a

specific gravity of 2.65, a particle size distribution closely matching the

distribution shown in Table 5, and total suspended sediment (TSS)

concentrations within 10% of 200 mg/L (180 mg/L – 220 mg/L TSS).

Table 5 Particle Size Distribution for Testing Alternative Post-Construction BMPs

Particle Size (microns)

Percent Finer (%)

1,000

100

500

250

150

100

Page 27 of 61

Ohio EPA Permit No.: OHC000006

• For field testing, the alternative BMP shall be tested using stormwater

runoff from the field, not altered by adding aggregate or subjecting to

unusually high sediment loads such as those from unstabilized

construction disturbance. The stormwater runoff used for field testing

shall be representative of runoff from the proposed installation site for

the alternative BMP after all construction activities have ceased and the

ground has been stabilized. The influent and effluent TSS

concentrations of stormwater runoff must be collected in the field.

• Testing of alternative post-construction BMPs shall be performed or

overseen by a qualified independent, third-party testing

organization;

• Testing shall demonstrate the maximum flow rate at which the

alternative post-construction BMP can achieve the necessary

treatment efficacy, including consideration for the potential of

sediment resuspension;

• Testing shall demonstrate the maximum volume of sediment and

floatables that can be collected in the alternative post-construction

BMP before pollutants must be removed to maintain 80% treatment

efficacy;

• Testing shall indicate the recommended maintenance frequency

and maintenance protocol to ensure ongoing performance of the

alternative post-construction BMP.

The alternative post-construction BMP testing protocol described in this

section is similar to testing requirements specified by the New Jersey

Department of Environmental Protection (NJDEP) for stormwater

Manufactured Treatment Devices (MTD) and therefore testing results

certified by NJDEP shall be accepted by Ohio EPA. For a list of BMPs

that have been certified by NJDEP, see the website:

www.njstormwater.org.

Another nationally recognized stormwater product testing procedure is

the Technology Assessment Protocol – Ecology (TAPE) administered

by the State of Washington, Department of Ecology. Testing results for

a proposed alternative post-construction BMPcertified by TAPE under

their general use designation and basic treatment category shall be

accepted by Ohio EPA. The State of Washington, Department of

Ecology website is https://ecology.wa.gov/.

Alternative post-construction BMPs may include, but are not limited to:

vegetated swales, vegetated filter strips, hydrodynamic separators,

high-flow media filters, cartridge filters, membrane filters, subsurface

flow wetlands, multi-chamber treatment trains, road shoulder media

filter drains, wetland channels, rain barrels, green roofs, and rain

gardens. The Director may also consider non-structural post-

construction approaches.

Page 28 of 61

Ohio EPA Permit No.: OHC000006

f. Surface Water Protection. If the project site contains any streams, rivers, lakes,

wetlands or other surface waters, certain construction activities at the site may be

regulated under the CWA and/or state isolated wetland permit requirements.

Sections 404 and 401 of the Act regulate the discharge of dredged or fill material

into surface waters and the impacts of such activities on water quality,

respectively. Construction activities in surface waters which may be subject to

CWA regulation and/or state isolated wetland permit requirements include, but

are not limited to: sewer line crossings, grading, backfilling or culverting streams,

filling wetlands, road and utility line construction, bridge installation and

installation of flow control structures. If the project contains streams, rivers, lakes

or wetlands or possible wetlands, the permittee shall contact the appropriate U.S.

Army Corps of Engineers District Office. (CAUTION: Any area of seasonally wet

hydric soil is a potential wetland - please consult the Soil Survey and list of hydric

soils for your County, available at your county’s Soil and Water Conservation

District. If you have any questions about Section 401 water quality certification,

please contact the Ohio Environmental Protection Agency, Section 401

Coordinator.)

U.S. Army Corps of Engineers (Section 404 regulation):

▪ Huntington, WV District (304) 399-5210 (Muskingum River, Hocking

River, Scioto River, Little Miami River, and Great Miami River Basins)

▪ Buffalo, NY District (716) 879-4330 (Lake Erie Basin)

▪ Pittsburgh, PA District (412) 395-7155 (Mahoning River Basin)

▪ Louisville, KY District (502) 315-6686 (Ohio River)

Ohio EPA 401/404 and non-jurisdictional stream/wetland coordinator can be

contacted at (614) 644-2001 (all of Ohio)

Concentrated stormwater runoff from BMPs to natural wetlands shall be

converted to diffuse flow before the runoff enters the wetlands. The flow should

be released such that no erosion occurs downslope. Level spreaders may need

to be placed in series, particularly on steep sloped sites, to ensure non-erosive

velocities. Other structural BMPs may be used between stormwater features and

natural wetlands, in order to protect the natural hydrology, hydroperiod, and

wetland flora. If the applicant proposes to discharge to natural wetlands, a

hydrologic analysis shall be performed. The applicant shall attempt to match the

pre-development hydroperiods and hydrodynamics that support the wetland.

The applicant shall assess whether their construction activity will adversely

impact the hydrologic flora and fauna of the wetland. Practices such as

vegetative buffers, infiltration basins, conservation of forest cover, and the

preservation of intermittent streams, depressions, and drainage corridors may be

used to maintain wetland hydrology.

g. Other controls.

i. Non-Sediment Pollutant Controls. In accordance with Part II.E, no

solid (other than sediment) or liquid waste, including building materials,

shall be discharged in stormwater runoff. The permittee must implement

all necessary BMPs to prevent the discharge of non-sediment pollutants

to the drainage system of the site or surface waters of the state or an

Page 29 of 61

Ohio EPA Permit No.: OHC000006

MS4. Under no circumstance shall wastewater from the washout of

concrete trucks, stucco, paint, form release oils, curing compounds, and

other construction materials be discharged directly into a drainage

channel, storm sewer or surface waters of the state. Also, no pollutants

from vehicle fuel, oils, or other vehicle fluids can be discharged to surface

waters of the state. No exposure of stormwater to waste materials is

recommended. The SWP3 must include methods to minimize the

exposure of building materials, building products, construction wastes,

trash, landscape materials, fertilizers, pesticides, herbicides, detergents,

and sanitary waste to precipitation, stormwater runoff, and snow melt. In

accordance with Part II.D.3, the SWP3 shall include measures to prevent

and respond to chemical spills and leaks. You may also reference the

existence of other plans (i.e., Spill Prevention Control and

Countermeasure (SPCC) plans, spill control programs, Safety Response

Plans, etc.) provided that such plan addresses conditions of this permit

condition and a copy of such plan is maintained on site.

ii. Off-site traffic. Off-site vehicle tracking of sediments and dust

generation shall be minimized. In accordance with Part II.D.1, the SWP3

shall include methods to minimize the discharge of pollutants from

equipment and vehicle washing, wheel washwater, and other

washwaters. No detergents may be used to wash vehicles. Washwaters

shall be treated in a sediment basin or alternative control that provides

equivalent treatment prior to discharge.

iii. Compliance with other requirements. The SWP3 shall be consistent

with applicable State and/or local waste disposal, sanitary sewer or septic

system regulations, including provisions prohibiting waste disposal by

open burning and shall provide for the proper disposal of contaminated

soils to the extent these are located within the permitted area.

iv. Trench and ground water control. In accordance with Part II.C, there

shall be no turbid discharges to surface waters of the state resulting from

dewatering activities. If trench or ground water contains sediment, it shall

pass through a sediment settling pond or other equally effective sediment

control device, prior to being discharged from the construction site.

Alternatively, sediment may be removed by settling in place or by

dewatering into a sump pit, filter bag or comparable practice. Ground

water which does not contain sediment or other pollutants is not required

to be treated prior to discharge. However, care must be taken when

discharging ground water to ensure that it does not become pollutant-

laden by traversing over disturbed soils or other pollutant sources.

v. Contaminated Sediment. Where construction activities are to occur on

sites with contamination from previous activities, operators shall be aware

that concentrations of materials that meet other criteria (is not considered

a Hazardous Waste, meeting VAP standards, etc.) may still result in

stormwater discharges in excess of Ohio Water Quality Standards. Such

discharges are not authorized by this permit. Appropriate BMPs include,

but are not limited to:

Page 30 of 61

Ohio EPA Permit No.: OHC000006

• The use of berms, trenches, and pits to collect contaminated

runoff and prevent discharges;

• Pumping runoff into a sanitary sewer (with prior approval of the

sanitary sewer operator) or into a container for transport to an

appropriate treatment/disposal facility; and

• Covering areas of contamination with tarps or other methods that

prevent stormwater from coming into contact with the material.

Operators should consult with Ohio EPA Division of Surface Water prior

to seeking permit coverage.

h. Maintenance. All temporary and permanent control practices shall be maintained

and repaired as needed to ensure continued performance of their intended

function. All sediment control practices must be maintained in a functional

condition until all up-slope areas they control are permanently stabilized. The

SWP3 shall be designed to minimize maintenance requirements. The applicant

shall provide a description of maintenance procedures needed to ensure the

continued performance of control practices.

i. Inspections. The permittee shall assign “qualified inspection personnel” to

conduct inspections to ensure that the control practices are functional and to

evaluate whether the SWP3 is adequate and properly implemented in

accordance with the schedule proposed in Part III.G.1.h of this permit or whether

additional control measures are required. At a minimum, procedures in a SWP3

shall provide that all controls on the site are inspected:

• after any storm event greater than one-half inch of rain per 24-hour period

by the end of the next calendar day, excluding weekends and holidays

unless work is scheduled; and

• once every seven calendar days.

The inspection frequency may be reduced to at least once every month for

dormant sites if:

• the entire site is temporarily stabilized or

• runoff is unlikely due to weather conditions for extended periods of time

(e.g., site is covered with snow, ice, or the ground is frozen).

The beginning and ending dates of any reduced inspection frequency shall be

documented in the SWP3. Once a definable area has achieved final stabilization,

the area may be marked on the SWP3 and no further inspection requirements

shall apply to that portion of the site.

Following each inspection, a checklist must be completed and signed by the

qualified inspection personnel representative. Inspection reports may be

prepared, signed, and kept electronically, rather than in paper form, if the records

are: (a) in a format that can be read in a similar manner as a paper record; (b)

legally dependable with no less evidentiary value than their paper equivalent; and

extent as a paper copy stored at the site would be, if the records were stored in

Page 31 of 61

Ohio EPA Permit No.: OHC000006

paper form. For additional guidance on the proper practices to follow for the

electronic retention of inspection report records, refer to this general permit’s

Fact Sheet at https://epa.ohio.gov/divisions-and-offices/surface-

water/permitting/storm-water-discharges-from-small-and-large-

construction-activities--general-permit. At a minimum, the inspection report

shall include:

i. the inspection date;

ii. names, titles, and qualifications of personnel making the inspection;

iii. weather information for the period since the last inspection (or since

commencement of construction activity if the first inspection) including a best

estimate of the beginning of each storm event, duration of each storm event,

approximate amount of rainfall for each storm event (in inches), and whether

any discharges occurred;

iv. weather information and a description of any discharges occurring at the time

of the inspection;

v. location(s) of discharges of sediment or other pollutants from the site;

vi. location(s) of BMPs that need to be maintained;

vii. location(s) of BMPs that failed to operate as designed or proved inadequate

for a particular location;

viii. location(s) where additional BMPs are needed that did not exist at the time of

inspection; and

ix. corrective action required including any changes to the SWP3 necessary and

implementation dates.

Disturbed areas and areas used for storage of materials that are exposed to

precipitation shall be inspected for evidence of or the potential for pollutants

entering the drainage system. Erosion and sediment control measures identified

in the SWP3 shall be observed to ensure that those are operating correctly.

Discharge locations shall be inspected to ascertain whether erosion and

sediment control measures are effective in preventing significant impacts to the

receiving waters. Locations where vehicles enter or exit the site shall be

inspected for evidence of off-site vehicle tracking.

The permittee shall maintain for three years following the submittal of a notice of

termination form, a record summarizing the results of the inspection, names(s)

and qualifications of personnel making the inspection, the date(s) of the

inspection, major observations relating to the implementation of the SWP3 and a

certification as to whether the facility is in compliance with the SWP3 and the

permit and identify any incidents of non-compliance. The record and certification

shall be signed in accordance with Part V.G. of this permit.

i. When practices require repair or maintenance. If the inspection

reveals that a control practice is in need of repair or maintenance, with

the exception of a sediment settling pond, it shall be repaired or

maintained within 3 days of the inspection. Sediment settling ponds shall

be repaired or maintained within 10 days of the inspection.

ii. When practices fail to provide their intended function. If the

inspection reveals that a control practice fails to perform its intended

Page 32 of 61

Ohio EPA Permit No.: OHC000006

function and that another, more appropriate control practice is required,

the SWP3 shall be amended and the new control practice shall be

installed within 10 days of the inspection.

iii. When practices depicted on the SWP3 are not installed. If the

inspection reveals that a control practice has not been implemented in

accordance with the schedule contained in Part III.G.1.h of this permit, the

control practice shall be implemented within 10 days from the date of the

inspection. If the inspection reveals that the planned control practice is

not needed, the record shall contain a statement of explanation as to why

the control practice is not needed.

3. Approved State or local plans. All dischargers regulated under this general permit

must comply, except those exempted under state law, with the lawful requirements of

municipalities, counties and other local agencies regarding discharges of stormwater

from construction activities. All erosion and sediment control plans and stormwater

management plans approved by local officials shall be retained with the SWP3 prepared

in accordance with this permit. Applicable requirements for erosion and sediment

control and stormwater management approved by local officials are, upon submittal of a

NOI form, incorporated by reference and enforceable under this permit even if they are

not specifically included in an SWP3 required under this permit. When the project is

located within the jurisdiction of a regulated municipal separate storm sewer system

(MS4), the permittee shall certify that the SWP3 complies with the requirements of the

stormwater management program of the MS4 operator.

4. Exceptions. If specific site conditions prohibit the implementation of any of the erosion

and sediment control practices contained in this permit or site-specific conditions are

such that implementation of any erosion and sediment control practices contained in this

permit will result in no environmental benefit, then the permittee shall provide justification

for rejecting each practice based on site conditions. Exceptions from implementing the

erosion and sediment control standards contained in this permit will be approved or

denied on a case-by-case basis.

The permittee may request approval from Ohio EPA to use alternative methods to satisfy

conditions in this permit if the permittee can demonstrate that the alternative methods

are sufficient to protect the overall integrity of receiving streams and the watershed.

Alternative methods will be approved or denied on a case-by-case basis.

PART IV. NOTICE OF TERMINATION REQUIREMENTS

A. Failure to notify.

The terms and conditions of this permit shall remain in effect until a signed Notice of

Termination (NOT) form is submitted and permit coverage is terminated by Ohio EPA. Failure

to submit an NOT constitutes a violation of this permit and may affect the ability of the permittee

to obtain general permit coverage in the future.

Page 33 of 61

Ohio EPA Permit No.: OHC000006

B. When to submit an NOT.

1. Permittees wishing to terminate coverage under this permit shall submit an NOT form in

accordance with Part V.G. of this permit. Compliance with this permit is required until an

NOT form is submitted and permit coverage is terminated by Ohio EPA. Prior to

submitting the NOT form, the permittee shall conduct a site inspection in accordance

with Part III.G.2.i of this permit and have a maintenance plan in place to ensure all post-

construction BMPs will be maintained in perpetuity.

2. All permittees shall submit an NOT form within 45 days of completing all permit

requirements. Enforcement actions may be taken if a permittee submits an NOT form

without meeting one or more of the following conditions:

a. Final stabilization (see definition in Part VII) has been achieved on all portions of

the site for which the permittee is responsible (including, if applicable, returning

agricultural land to its pre-construction agricultural use);

b. Another operator(s) has assumed control over all areas of the site that have not

been finally stabilized;

c. A maintenance plan is in place to ensure all post construction BMPs are

adequately maintained in the long-term;

d. For non-residential developments, all elements of the stormwater pollution

prevention plan have been completed, the disturbed soil at the identified facility

have been stabilized and temporary erosion and sediment control measures

have been removed at the appropriate time, or all stormwater discharges

associated with construction activity from the identified facility that are authorized

by the above referenced NPDES general permit have otherwise been eliminated.

(i)For residential developments only, temporary stabilization has been completed

and the lot, which includes a home, has been transferred to the homeowner; (ii)

final stabilization has been completed and the lot, which does not include a

home, has been transferred to the property owner; (iii) no stabilization has been

implemented on a lot, which includes a home, and the lot has been transferred to

the homeowner; or

e. An exception has been granted under Part III.G.4.

C. How to submit an NOT.

To terminate permit coverage, the permitee shall submit a complete and accurate Notice of

Termination (NOT) form using Ohio EPA’s electronic application form which is available through

the Ohio EPA eBusiness Center at: https://ebiz.epa.ohio.gov/. Submission through the Ohio

EPA eBusiness Center will require establishing an Ohio EPA eBusiness Center account and

obtaining a unique Personal Identification Number (PIN) for final submission of the

NOT. Existing eBusiness Center account holders can access the NOT form through their

existing account and submit using their existing PIN. Please see the following link for guidance:

https://epa.ohio.gov/divisions-and-offices/surface-water/permitting/electronic-business-

services-sub/streams. Alternatively, if you are unable to access the NOT form through the

agency eBusiness Center due to a demonstrated hardship, the NOT may be submitted on paper

NOT forms provided by Ohio EPA. NOT information shall be typed on the form. Please contact

Page 34 of 61

Ohio EPA Permit No.: OHC000006

Ohio EPA, Division of Surface Water at (614) 644-2001 if you wish to receive a paper NOT

form.

PART V. STANDARD PERMIT CONDITIONS.

A. Duty to comply.

The permittee shall comply with all conditions of this permit. Any permit noncompliance

constitutes a violation of ORC Chapter 6111 and is grounds for enforcement action.

Ohio law imposes penalties and fines for persons who knowingly make false statements or

knowingly swear or affirm the truth of a false statement previously made.

B. Continuation of an expired general permit.

An expired general permit continues in force and effect until a new general permit is issued.

C. Need to halt or reduce activity not a defense.

It shall not be a defense for a permittee in an enforcement action that it would have been

necessary to halt or reduce the permitted activity in order to maintain compliance with the

conditions of this permit.

D. Duty to mitigate.

The permittee shall take all reasonable steps to minimize or prevent any discharge in violation

of this permit which has a reasonable likelihood of adversely affecting human health or the

environment.

E. Duty to provide information.

The permittee shall furnish to the director, within 10 days of written request, any information

which the director may request to determine whether cause exists for modifying, revoking and

reissuing, or terminating this permit or to determine compliance with this permit. The permittee

shall also furnish to the director upon request copies of records required to be kept by this

permit.

F. Other information.

When the permittee becomes aware that he or she failed to submit any relevant facts or

submitted incorrect information in the NOI, SWP3, NOT or in any other report to the director, he

or she shall promptly submit such facts or information.

G. Signatory requirements.

All NOIs, NOTs, SWP3s, reports, certifications or information either submitted to the director or

that this permit requires to be maintained by the permittee, shall be signed.

1. These items shall be signed as follows:

Page 35 of 61

Ohio EPA Permit No.: OHC000006

a. For a corporation: By a responsible corporate officer. For the purpose of this

section, a responsible corporate officer means:

i. A president, secretary, treasurer or vice-president of the corporation in

charge of a principal business function or any other person who performs

similar policy or decision-making functions for the corporation; or

ii. The manager of one or more manufacturing, production or operating

facilities, provided, the manager is authorized to make management

decisions that govern the operation of the regulated facility including

having the explicit or implicit duty of making major capital investment

recommendations and initiating and directing other comprehensive

measures to assure long-term environmental compliance with

environmental laws and regulations; the manager can ensure that the

necessary systems are established or actions taken to gather complete

and accurate information for permit application requirements; and where

authority to sign documents has been assigned or delegated to the

manager in accordance with corporate procedures;

b. For a partnership or sole proprietorship: By a general partner or the proprietor,

respectively; or

c. For a municipality, State, Federal or other public agency: By either a principal

executive officer or ranking elected official. For purposes of this section, a

principal executive officer of a Federal agency includes (1) the chief executive

officer of the agency or (2) a senior executive officer having responsibility for the

overall operations of a principal geographic unit of the agency (e.g., Regional

Administrators of U.S. EPA).

2. All reports required by the permits and other information requested by the director shall

be signed by a person described in Part V.G.1 of this permit or by a duly authorized

representative of that person. A person is a duly authorized representative only if:

a. The authorization is made in writing by a person described in Part V.G.1 of this

permit and submitted to the director;

b. The authorization specifies either an individual or a position having responsibility

for the overall operation of the regulated facility or activity, such as the position of

manager, operator of a well or well field, superintendent, position of equivalent

responsibility or an individual or position having overall responsibility for

environmental matters for the company. (A duly authorized representative may

thus be either a named individual or any individual occupying a named position);

and

c. The written authorization is submitted to the director.

3. Changes to authorization. If an authorization under Part V.G.2 of this permit is no longer

accurate because a different individual or position has responsibility for the overall

operation of the facility, a new authorization satisfying the requirements of Part V.G.2 of

Page 36 of 61

Ohio EPA Permit No.: OHC000006

this permit must be submitted to the director prior to or together with any reports,

information or applications to be signed by an authorized representative.

H. Certification.

Any person signing documents under this section shall make the following certification:

"I certify under penalty of law that this document and all attachments were

prepared under my direction or supervision in accordance with a system

designed to assure that qualified personnel properly gathered and evaluated the

information submitted. Based on my inquiry of the person or persons who

manage the system or those persons directly responsible for gathering the

information, the information submitted is, to the best of my knowledge and belief,

true, accurate and complete. I am aware that there are significant penalties for

submitting false information, including the possibility of fine and imprisonment for

knowing violations."

I. Oil and hazardous substance liability.

Nothing in this permit shall be construed to preclude the institution of any legal action or relieve

the permittee from any responsibilities, liabilities or penalties to which the permittee is or may be

subject under section 311 of the CWA or 40 CFR Part 112. 40 CFR Part 112 establishes

procedures, methods and equipment and other requirements for equipment to prevent the

discharge of oil from non-transportation-related onshore and offshore facilities into or upon the

navigable surface waters of the state or adjoining shorelines.

J. Property rights.

The issuance of this permit does not convey any property rights of any sort, nor any exclusive

privileges, nor does it authorize any injury to private property nor any invasion of personal rights,

nor any infringement of Federal, State or local laws or regulations.

K. Severability.

The provisions of this permit are severable and if any provision of this permit or the application

of any provision of this permit to any circumstance is held invalid, the application of such

provision to other circumstances and the remainder of this permit shall not be affected thereby.

L. Transfers.

Ohio NPDES general permit coverage is transferable. Ohio EPA must be notified in writing sixty

days prior to any proposed transfer of coverage under an Ohio NPDES general permit. The

transferee must inform Ohio EPA it will assume the responsibilities of the original permittee

transferor.

M. Environmental laws.

No condition of this permit shall release the permittee from any responsibility or requirements

under other environmental statutes or regulations.

Page 37 of 61

Ohio EPA Permit No.: OHC000006

N. Proper operation and maintenance.

The permittee shall at all times properly operate and maintain all facilities and systems of

treatment and control (and related appurtenances) which are installed or used by the permittee

to achieve compliance with the conditions of this permit and with the requirements of SWP3s.

Proper operation and maintenance requires the operation of backup or auxiliary facilities or

similar systems, installed by a permittee only when necessary to achieve compliance with the

conditions of the permit.

O. Inspection and entry.

The permittee shall allow the director or an authorized representative of Ohio EPA, upon the

presentation of credentials and other documents as may be required by law, to:

1. Enter upon the permittee's premises where a regulated facility or activity is located or

conducted or where records must be kept under the conditions of this permit;

2. Have access to and copy at reasonable times, any records that must be kept under the

conditions of this permit;

3. Inspect at reasonable times any facilities or equipment (including monitoring and control

equipment); and

4. Sample or monitor at reasonable times, for the purposes of assuring permit compliance

or as otherwise authorized by the Clean Water Act, any substances or parameters at

any location.

P. Duty to Reapply.

If the permittee wishes to continue an activity regulated by this permit after the expiration date of

this permit, the permittee must apply for and obtain a new permit.

Q. Permit Actions.

This permit may be modified, revoked and reissued, or terminated for cause. The filing of a

request by the permittee for a permit modification, revocation and reissuance, or termination, or

a notification of planned changes or anticipated noncompliance does not stay any permit

condition.

R. Bypass.

The provisions of 40 CFR Section 122.41(m), relating to “Bypass,” are specifically incorporated

herein by reference in their entirety. For definition of “Bypass,” see Part VII.C.

S. Upset.

The provisions of 40 CFR Section 122.41(n), relating to “Upset,” are specifically incorporated

herein by reference in their entirety. For definition of “Upset,” see Part VII.GG.

Page 38 of 61

Ohio EPA Permit No.: OHC000006

T. Monitoring and Records.

The provisions of 40 CFR Section 122.41(j), relating to “Monitoring and Records,” are

specifically incorporated herein by reference in their entirety.

U. Reporting Requirements.

The provisions of 40 CFR Section 122.41(l), relating to “Reporting Requirements,” are

specifically incorporated herein by reference in their entirety.

V. General Effluent Limitation

The effluent shall, at all times, be free of substances:

1. In amounts that will settle to form putrescent, or otherwise objectionable, sludge

deposits; or that will adversely affect aquatic life or waterfowl;

2. Of an oily, greasy, or surface-active nature, and of other floating debris, in amounts that

will form noticeable accumulations of scum, foam, or sheen;

3. In amounts that will alter the natural color or odor of the receiving water to such degree

as to create a nuisance;

4. In amounts that either singly or in combination with other substances are toxic to human,

animal, or aquatic life;

5. In amounts that are conducive to the growth of aquatic weeds or algae to the extent that

such growth become inimical to more desirable forms of aquatic life, or create conditions

that are unsightly, or constitute a nuisance in any other fashion;

6. In amounts that will impair designated instream or downstream water uses.

PART VI. REOPENER CLAUSE

If there is evidence indicating potential or realized impacts on water quality due to any

stormwater discharge associated with construction activity covered by this permit, the permittee

of such discharge may be required to obtain coverage under an individual permit or an

alternative general permit in accordance with Part I.C of this permit or the permit may be

modified to include different limitations and/or requirements.

Permit modification or revocation will be conducted according to ORC Chapter 6111.

PART VII. DEFINITIONS

A. “Act” means Clean Water Act (formerly referred to as the Federal Water Pollution

Control Act or Federal Water Pollution Control Act Amendments of 1972) Pub. L. 92-

500, as amended Pub. L. 95-217, Pub. L. 95-576, Pub. L. 96-483, Pub. L. 97-117 and

Pub. L. 100-4, 33 U.S.C. 1251 et. seq.

B. “Bankfull channel” means a channel flowing at channel capacity and conveying the

bankfull discharge. Delineated by the highest water level that has been maintained for a

sufficient period of time to leave evidence on the landscape, such as the point where the

natural vegetation changes from predominantly aquatic to predominantly terrestrial or

the point at which the clearly scoured substrate of the stream ends and terrestrial

vegetation begins.

Page 39 of 61

Ohio EPA Permit No.: OHC000006

C. “Bankfull discharge” means the streamflow that fills the main channel and just begins to

spill onto the floodplain; it is the discharge most effective at moving sediment and

forming the channel.

D. “Best management practices (BMPs)” means schedules of activities, prohibitions of

practices, maintenance procedures and other management practices (both structural

and non-structural) to prevent or reduce the pollution of surface waters of the state.

BMP's also include treatment requirements, operating procedures and practices to

control plant and/or construction site runoff, spillage or leaks, sludge or waste disposal

or drainage from raw material storage.

E. “Bypass” means the intentional diversion of waste streams from any portion of a

treatment facility.

F. “Channelized stream” means the definition set forth in Section 6111.01 (M) of the ORC.

G. “Commencement of construction” means the initial disturbance of soils associated with

clearing, grubbing, grading, placement of fill, or excavating activities or other

construction activities.

H. “Concentrated stormwater runoff” means any stormwater runoff which flows through a

drainage pipe, ditch, diversion or other discrete conveyance channel.

I. “Director” means the director of the Ohio Environmental Protection Agency.

J. “Discharge” means the addition of any pollutant to the surface waters of the state from a

point source.

K. “Disturbance” means any clearing, grading, excavating, filling, or other alteration of land

surface where natural or man-made cover is destroyed in a manner that exposes the

underlying soils.

L. “Drainage watershed” means for purposes of this permit the total contributing drainage

area to a BMP, i.e., the “watershed” directed to the practice. This would also include any

off-site drainage.

M. “Final stabilization” means that either:

1. All soil disturbing activities at the site are complete and a uniform perennial

vegetative cover (e.g., evenly distributed, without large bare areas) with a density

of at least 70 percent cover for the area has been established on all unpaved

areas and areas not covered by permanent structures or equivalent stabilization

measures (such as the use of mulches, rip-rap, gabions or geotextiles) have

been employed. In addition, all temporary erosion and sediment control

practices are removed and disposed of and all trapped sediment is permanently

stabilized to prevent further erosion; or

2. For individual lots in residential construction by either:

a. The homebuilder completing final stabilization as specified above or

Page 40 of 61

Ohio EPA Permit No.: OHC000006

b. The homebuilder establishing temporary stabilization including perimeter

controls for an individual lot prior to occupation of the home by the

homeowner and informing the homeowner of the need for and benefits of,

final stabilization. (Homeowners typically have an incentive to put in the

landscaping functionally equivalent to final stabilization as quick as

possible to keep mud out of their homes and off sidewalks and

driveways.); or

3. For construction projects on land used for agricultural purposes (e.g., pipelines

across crop or range land), final stabilization may be accomplished by returning

the disturbed land to its pre-construction agricultural use. Areas disturbed that

were previously used for agricultural activities, such as buffer strips immediately

adjacent to surface waters of the state and which are not being returned to their

pre-construction agricultural use, must meet the final stabilization criteria in (1) or

(2) above.

N. “General contractor” – for the purposes of this permit, the primary individual or company

solely accountable to perform a contract. The general contractor typically supervises

activities, coordinates the use of subcontractors, and is authorized to direct workers at a

site to carry out activities required by the permit.

O. “Individual lot NOI” means a Notice of Intent for an individual lot to be covered by this

permit (see Part I of this permit).

P. “Larger common plan of development or sale”- means a contiguous area where multiple

separate and distinct construction activities may be taking place at different times on

different schedules under one plan.

Q. “MS4" means municipal separate storm sewer system which means a conveyance or

system of conveyances (including roads with drainage systems, municipal streets, catch

basins, curbs, gutters, ditches, man-made channels or storm drains) that are:

1. Owned or operated by the federal government, state, municipality, township,

county, district(s) or other public body (created by or pursuant to state or federal

law) including special district under state law such as a sewer district, flood

control district or drainage districts or similar entity or a designated and approved

management agency under section 208 of the act that discharges into surface

waters of the state; and

2. Designed or used for collecting or conveying solely stormwater,

3. Which is not a combined sewer and

4. Which is not a part of a publicly owned treatment works.

R. “National Pollutant Discharge Elimination System (NPDES)” means the national program

for issuing, modifying, revoking and reissuing, terminating, monitoring and enforcing

permits and enforcing pretreatment requirements, under sections 307, 402, 318 and 405

of the CWA. The term includes an "approved program.”

S. “Natural channel design” means an engineering technique that uses knowledge of the

natural process of a stream to create a stable stream that will maintain its form and

function over time.

Page 41 of 61

Ohio EPA Permit No.: OHC000006

T. “NOI” means notice of intent to be covered by this permit.

U. “NOT” means notice of termination.

V. “Operator” means any party associated with a construction project that meets either of

the following two criteria:

1. The party has day-to-day operational control of all activities at a project which are

necessary to ensure compliance with a SWP3 for the site and all permit

conditions including the ability to authorize modifications to the SWP3,

construction plans and site specification to ensure compliance with the General

Permit, or

2. Property owner meets the definition of operator should the party which has day to

day operational control require additional authorization from the owner for

modifications to the SWP3, construction plans, and/or site specification to ensure

compliance with the permit or refuses to accept all responsibilities as listed above

(Part VII.V.1).

Subcontractors generally are not considered operators for the purposes of this permit.

As set forth in Part I.F.1, there can be more than one operator at a site and under these

circumstances, the operators shall be co-permittees.

W. “Ordinary high water mark” means that line on the shore established by the fluctuations

of water and indicated by physical characteristics such as clear, natural line impressed

on the bank, shelving, changes in the character of soil, destruction of terrestrial

vegetation, the presence of litter and debris, or other appropriate means that consider

the characteristics of the surrounding areas.

X. “Owner or operator” means the owner or operator of any “facility or activity” subject to

regulation under the NPDES program.

Y. “Permanent stabilization” means the establishment of permanent vegetation, decorative

landscape mulching, matting, sod, rip rap and landscaping techniques to provide

permanent erosion control on areas where construction operations are complete or

where no further disturbance is expected for at least one year.

Z. “Percent imperviousness” means the impervious area created divided by the total area

of the project site.

AA. “Point source” means any discernible, confined and discrete conveyance, including but

not limited to, any pipe, ditch, channel, tunnel, conduit, well, discrete fissure, container,

rolling stock, concentrated animal feeding operation, landfill leachate collection system,

vessel or the floating craft from which pollutants are or may be discharged. This term

does not include return flows from irrigated agriculture or agricultural stormwater runoff.

BB. “Qualified inspection personnel” means a person knowledgeable in the principles and

practice of erosion and sediment controls, who possesses the skills to assess all

conditions at the construction site that could impact stormwater quality and to assess

Page 42 of 61

Ohio EPA Permit No.: OHC000006

the effectiveness of any sediment and erosion control measures selected to control the

quality of stormwater discharges from the construction activity.

CC. “Rainwater and Land Development” is a manual describing construction and post-

construction best management practices and associated specifications. A copy of the

manual is maintained on the Ohio EPA website.

DD. “Riparian area” means the transition area between flowing water and terrestrial (land)

ecosystems composed of trees, shrubs and surrounding vegetation which serve to

stabilize erodible soil, improve both surface and ground water quality, increase stream

shading and enhance wildlife habitat.

EE. “Runoff coefficient” means the fraction of total rainfall that will appear at the conveyance

as runoff.

FF. “Sediment settling pond” means a sediment trap, sediment basin or permanent basin

that has been temporarily modified for sediment control, as described in the latest edition

of the Rainwater and Land Development manual.

GG. “State isolated wetland permit requirements” means the requirements set forth in

Sections 6111.02 through 6111.029 of the ORC.

HH. “Stormwater” means stormwater runoff, snow melt and surface runoff and drainage.

II. “Steep slopes” means slopes that are 15 percent or greater in grade. Where a local

government or industry technical manual has defined what is to be considered a “steep

slope,” this permit’s definition automatically adopts that definition.

JJ. “Stream edge” means the ordinary high water mark.

KK. “Subcontractor” – for the purposes of this permit, an individual or company that takes a

portion of a contract from the general contractor or from another subcontractor.

LL. “Surface waters of the state” or “water bodies” means all streams, lakes, reservoirs,

ponds, marshes, wetlands or other waterways which are situated wholly or partially

within the boundaries of the state, except those private waters which do not combine or

effect a junction with natural surface or underground waters. Waters defined as

sewerage systems, treatment works or disposal systems in Section 6111.01 of the ORC

are not included.

MM. “SWP3” means stormwater pollution prevention plan.

NN. “Upset” means an exceptional incident in which there is unintentional and temporary

noncompliance with technology based permit effluent limitations because of factors

beyond the reasonable control of the permittee. An upset does not include

noncompliance to the extent caused by operational error, improperly designed treatment

facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or

improper operation.

Page 43 of 61

Ohio EPA Permit No.: OHC000006

OO. “Temporary stabilization” means the establishment of temporary vegetation, mulching,

geotextiles, sod, preservation of existing vegetation and other techniques capable of

quickly establishing cover over disturbed areas to provide erosion control between

construction operations.

PP. “Water Quality Volume (WQ

)” means the volume of stormwater runoff which must be

captured and treated prior to discharge from the developed site after construction is

complete.

Page 44 of 61

Ohio EPA Permit No.: OHC000006

APPENDICES

Appendix A

A. Big Darby Creek Watershed

CONTENTS OF THIS APPENDIX

A.1 Permit Area

A.2 TMDL Conditions

A.3 Sediment Settling Ponds and Sampling

A.4 Post-Construction Stormwater Management Selection

A.5 Riparian Setback Requirements

A.6 Riparian Setback Mitigation

A.7 Groundwater Recharge Requirements

A.8 Groundwater Recharge mitigation

Attachment A-A: Big Darby Creek Watershed Map

Attachment A-B: Stream Assessment and Restoration

A.1 Permit Area.

This appendix to Permit OHC00006 applies to the entire Big Darby Creek Watershed

located within the State of Ohio. Please see Attachment A for permit area boundaries.

A.2 TMDL Conditions.

This general permit requires control measures/BMPs for construction sites that reflect

recommendations set forth in the U.S. EPA approved Big Darby Creek TMDL.

A.3 Sediment Settling Ponds and Sampling

Sediment settling ponds additional conditions. The sediment settling pond shall be sized

to provide a minimum dewatering volume of 134 cubic yards per acre of drainage area

and maintain a target discharge performance standard of 45 mg/l Total Suspended Solids

(TSS) or 50 Nephelometric Turbidity Units (NTUs) up to a 0.75-inch rainfall event within a

24-hour period. Unless infeasible, sediment settling ponds must be dewatered at the pond

surface using a skimmer or equivalent device. The depth of the sediment settling pond

must be less than or equal to five feet. Sediment must be removed from the sediment

settling pond when the design capacity has been reduced by 40 percent (This is typically

reached when sediment occupies one-half of the basin depth).

Silt Fence and Diversions. For sites five or more acres in size, the use of sediment barriers

as a primary sediment control is prohibited. Centralized sediment basins shall be used

for sites 5 or more acres in size. Diversions shall direct all stormwater runoff from the

disturbed areas to the impoundment intended for sediment control. The sediment basins

and associated diversions shall be implemented prior to the major earth disturbing activity.

The permittee shall sample in accordance with sampling procedures outlined in 40 CFR

136. Sampling shall occur as follows:

i. Occur at the outfall of each sediment settling pond associated with the site. Each

associated outfall shall be identified by a three-digit number (001, 002, etc.);

Page 45 of 61

Ohio EPA Permit No.: OHC000006

ii. The applicable rainfall event for sampling to occur shall be a rainfall event of 0.25-

inch to a 0.75-inch rainfall event to occur within a 24-hour period. Grab sampling

shall be initiated at a site within 14 days, or the first applicable rainfall event

thereafter, once upslope disturbance of each sampling location is initiated and

shall continue on a quarterly basis. Quarterly periods shall be represented as

January - March, April - June, July - September and October - December.

Sampling results shall be retained on site and available for inspection.

If any sample is greater than the performance standard of 45 mg/l TSS or

50 NTUs, the permittee shall modify the SWP3 and install/implement new

control practice(s) within 10 days to ensure the performance standard is

maintained. Within 3 days of improvement(s), or the first applicable rainfall

event thereafter, the permittee shall resample to ensure SWP3

modifications maintain the performance standard target.

For each sample taken, the permittee shall record the following information:

• the outfall and date of sampling;

• the person(s) who performed the sampling;

• the date the analyses were performed on those samples;

• the person(s) who performed the analyses;

• the analytical techniques or methods used; and

• the results of all analyses.

Both quarterly and sampling results following a discharge target

exceedance shall be retained on site and available for inspection.

A.4 Post-Construction Stormwater Management Selection.

For all construction activities authorized under this permit that fall within the watershed of

the Big Darby Creek, a Table 4b practice shall be used to treat stormwater runoff for

pollutants, to reduce adverse impacts on receiving waters, and to further support

groundwater recharge if feasible. The applicant must provide a justification in the SWP3

why the use of table 4b practices are not feasible. The justification must address limiting

factors which would prohibit the project going forward should Table 4b practices be

required. Please note that practices selected will require approval from the regulated

MS4.

A.5 Riparian Setback Requirements.

The SWP3 shall clearly delineate the boundary of required stream setback distances.

No construction activity shall occur, without appropriate mitigation, within the delineated

setback boundary except activities associated with restoration or recovery of natural

floodplain and channel form characteristics as described in Attachment B, stormwater

conveyances from permanent treatment practices and approvable utility crossings.

Such conveyances must be designed to minimize the width of disturbance. If intrusion

within the delineated setback boundary is necessary to accomplish the purposes of a

project, then mitigation shall be required in accordance with Appendix A.6 of this permit.

Streams requiring protection under this section are defined as perennial, intermittent or

jurisdictional ephemeral streams with a defined bed, bank or channel. National

Resources Conservation Service (NRCS) soil survey maps should be used as one

Page 46 of 61

Ohio EPA Permit No.: OHC000006

reference and the presence of a stream requiring protection should also be confirmed in

the field. Any required setback distances shall be clearly displayed in the field prior to

any construction related activity.

Riparian setbacks distance shall be delineated based upon one of the following two

methods:

i. The setback distance shall be sized as the greater of the following:

1. The regulatory 100-year floodplain based on FEMA mapping;

2. A minimum of 100 feet from the top of the streambank on each

side; or

3. A distance calculated using the following equation:

W = 133DA

0.43

(Equation 1, Appendix A)

where:

DA = drainage area (mi

)

W = total width of riparian setback (ft)

W shall be centered over the meander pattern of the stream such that a

line representing the setback width would evenly intersect equal elevation

lines on either side of the stream.

If the DA remains relatively constant throughout the stretch of interest,

then the DA of the downstream edge of the stretch should be used.

Where there is a significant increase in the DA from the upstream edge to

The downstream edge of the area of interest, the setback width shall

increase accordingly.

ii. Stream Restoration with 100 feet (each side) Riparian Setback. Each

stream segment within the proposed site boundaries can be assessed in

accordance with Attachment B, Part 1. In the event the stream segment

is classified as a “Previously Modified Low Gradient Headwater Stream”,

the permittee has the option to restore the stream segment in accordance

with Attachment B and include a 100-foot water quality setback distance

from the top of the streambank on each side. In the event the stream

segment exceeds the minimum criteria in Attachment B to be classified as

a “Previously Modified Low Gradient Headwater Stream,” this Appendix

A, Attachment B may be considered on a case-by-case basis.

No structural sediment controls (e.g., the installation of sediment barriers or a sediment

settling pond) or structural post-construction controls shall be used in a surface water of

the State or the delineated setback corridor.

Previously developed projects (as defined in Part III.G.2.e.) located within the delineated

setback boundary are exempt from Riparian Setback Mitigation (A.6) provided the

proposed project does not further intrude into the delineated setback boundary.

Page 47 of 61

Ohio EPA Permit No.: OHC000006

Linear transportation projects which are caused solely by correcting safety related

issues, mandates of modern design requirements and/or resulting from other mitigation

activities are exempt from Riparian Setback Mitigation (Appendix A, A.6) if less than one

acre of total new right-of-way is associated with the project.A.6 Riparian Setback

Mitigation.

The mitigation required for intrusion into the riparian setback shall be determined by the

horizontal distance the intrusion is from the stream. Up to three zones will be used in

determining the required mitigation. Zone 1 extends from 0 to 25 feet from the stream

edge. Zone 2 extends from 25 to 100 feet from the stream edge, and Zone 3 extends

from 100 feet to the outer edge of the setback corridor. Intrusion into these zones will

require the following mitigation within the same Watershed Assessment Unit (12-digit

HUC scale):

i. Four times the total area disturbed in the stream and within Zone 1 of the

site being developed shall be mitigated within Zone 1 of the mitigation

location.

ii. Three times the area disturbed within Zone 2 of the site being developed

shall be mitigated within Zones 1 and/or 2 of the mitigation location.

iii. Two times the area disturbed within Zone 3 of the site being developed

shall be mitigated within any zone of the mitigation location.

In lieu of mitigation ratios found within in this section, linear transportation projects which

result in total new right-of-way greater than one acre and less than two acres, which are

caused solely by correcting safety related issues, mandates of modern design

requirements and/or resulting from other mitigation activities, shall provide Riparian

Setback Mitigation at a ratio of 1.5 to 1.

All mitigation shall, at a minimum, include conserved or restored setback zone and

should be designed to maximize the ecological function of the mitigation. Including

mitigation at the stream edge along with associated setback areas is one way to

maximize ecological function. Mitigation shall be protected in perpetuity by binding

conservation easements or environmental covenants which must be recorded within 6

months of receiving permit authorization. Granting of binding conservation easements or

environmental covenants protected in perpetuity for land outside of disturbed area but

within a required riparian setback counts towards required mitigation.

Mitigation may also be satisfied by approved pooled mitigation areas and in-lieu fee

sponsored mitigation areas. Mitigation resulting from State or Federal environmental

regulations may be adjusted in recognition of these requirements.

A.7 Groundwater Recharge Requirements.

The SWP3 shall ensure that the overall site post-development groundwater recharge

equals or exceeds the pre-development groundwater recharge. The SWP3 shall

describe the conservation development strategies, BMPs and other practices deemed

necessary by the permittee to maintain or improve pre-development rates of

Page 48 of 61

Ohio EPA Permit No.: OHC000006

groundwater recharge. Pre-development and post-development groundwater recharge

shall be calculated using the following equation:

i. Vre

= A

* Dre

/ 12 (Equation 2, Appendix A)

where:

X = represents a land use and hydrologic soil group pair

Vre

= volume of total annual recharge from land use-soil group X

(in acre-ft)

Dre

= depth of total annual recharge associated with land use-soil

group X from Tables 1 or 2 (in inches)

= area of land use-soil group X (in acres)

Table A-1 values should be used for land where the underlying geology indicates a

potential for downward migration of groundwater. Table A-1 values represent the

combined total groundwater recharge potential including groundwater contribution to

stream baseflow and to the underlying bedrock aquifer. The potential for downward

migration can be determined from a comparison of the potentiometric maps for the

glacial and bedrock aquifers. Use Table A-2 when this potential is unlikely to exist. See

attachment B for a map of Table A-1 and A-2 areas. Detailed potentiometric maps for

the Franklin county portion of the Darby watershed, and coarse potentiometric maps for

the Darby watershed outside of Franklin County and hydrologic soil group data are

available at:

https://epa.ohio.gov/divisions-and-offices/surface-water/permitting/stormwater-

program.

Table A-1 (Appendix A) Annual Average Expected Total Groundwater Recharge

Density

(DU

/acre)

% Impervious

Recharge (inches) by Hydrologic Soil Group2

Apply the following land covers when calculating an area-weighted average value for the site.

Woods / Forest

17.0

16.6

15.6

14.6

Brush

17.0

16.6

15.6

14.6

Meadow

17.0

16.5

15.4

14.4

Managed Wood

16.9

16.0

14.7

13.4

Pasture

16.5

15.9

14.4

13.0

Row Crop

15.8

14.2

11.9

8.1

Urban Grasses

15.7

14.2

12.7

Impervious

0.0

Alternatively, the following land use average values may be applied to the site as a whole.

Low Density Residential

0.5

12%

15.7

14.2

12.7

Low Density Residential

20%

14.8

13.7

12.2

Medium Density Residential

25%

11.5

Medium Density Residential

30%

11.2

Medium Density Residential

38%

9.6

High Density Residential

≥5

65%

7.3

Commercial & Road Right-of-Way

90%

4.3

DU = Dwelling Units

Hydrologic soil group designations of A/D, B/D, and C/D should be considered as D soils for this

application.

These values apply when recharge of the aquifer is expected; recharge to the bedrock aquifer can be

expected when the potentiometric head of the glacial aquifer is greater than the bedrock aquifer.

Page 49 of 61

Ohio EPA Permit No.: OHC000006

). These values may be used where total pervious and impervious areas within the development are

tabulated separately..

These values may only be used for an area as a whole (includes impervious and pervious areas).

Table A-2 (Appendix A) Annual Average Expected Baseflow Recharge

Density

(DU

/acre)

% Impervious

Recharge (inches) by Hydrologic Soil Group2

Apply the following land covers when calculating an area-weighted average value for the site.

Woods / Forest

11.8

11.4

10.7

9.9

Brush

11.7

11.4

10.7

9.9

Meadow

11.8

11.3

10.6

9.8

Managed Wood

11.7

11.0

10.0

9.1

Pasture

11.3

11.0

9.9

8.9

Row Crop

11.1

10.1

9.0

6.2

Urban Grasses

11.2

10.3

9.3

Impervious

0.0

Alternatively, the following land use average values may be applied to the site as a whole.

Low Density Residential

0.5

12%

11.2

10.3

9.3

Low Density Residential

20%

9.5

9.0

8.6

Medium Density Residential

25%

7.8

Medium Density Residential

30%

7.6

Medium Density Residential

38%

6.5

High Density Residential

≥5

65%

5.0

Commercial & Road Right-of-Way

90%

2.9

DU = Dwelling Units

Hydrologic soil group designations of A/D, B/D, and C/D should be considered as D soils for this

application.

These values apply when no recharge of the aquifer is expected.

These values may be used where total impervious and pervious areas are tabulated separately.

These values may only be used for an area as a whole (includes impervious and pervious areas).

Table A-3 (Appendix A) Land Use Definitions

Land Use

Definition

Woods / Forest

Areas dominated by trees. Woods are protected from grazing and litter and

brush adequately cover the soil.

Brush

Brush, weeds, grass mixture where brush is the major element and more than

75% of the ground is covered.

Meadow

Continuous grass, protected from grazing, generally mowed for hay.

Managed Wood

Orchards, tree farms, and other areas planted or maintained for the production

of fruits, nuts, berries, or ornamentals.

Pasture

Pasture, grassland, or range where at least 50% of the ground is covered and

the area is not heavily grazed.

Row Crop

Areas used to produce crops, such as corn, soybeans, vegetables, tobacco,

and cotton.

Urban Grasses

Vegetation (primarily grasses) planted in developed settings for recreation,

erosion control, or aesthetic purposes. Examples include parks, lawns, golf

courses, airport grasses, and industrial site grasses.

Residential

Areas with a mixture of constructed materials and vegetation; the average %

imperviousness and number of dwelling units per acre to determine the

appropriate density is specified.

Commercial

Includes infrastructure (e.g. roads, railroads, etc.) and all highly developed

areas not classified as High Intensity Residential.

Page 50 of 61

Ohio EPA Permit No.: OHC000006

ii. The pre-development ground water recharge volume shall be calculated

by determining the area of each land use-soil type pairing on the site of

interest. The recharge associated with each such pairing multiplied by

the area will give the pre-development volume of total groundwater

recharge. The same shall be done for the post-development land use-soil

type pairings.

Any activity that is expected to produce stormwater runoff with elevated

concentrations of carcinogens, hydrocarbons, metals, or toxics is prohibited from

infiltrating untreated stormwater from the area affected by the activity. The

groundwater recharge mitigation requirement for areas affected by such activities

must be met by methods which do not present a risk of groundwater

contamination. The following land uses and activities are typically deemed

stormwater hotspots:

Vehicle salvage yards and recycling facilities

• vehicle service and maintenance facilities (i.e. truck stops, gas stations)

• fleet storage areas (i.e. bus, truck)

• industrial sites subject to industrial stormwater permitting requirements

• bulk terminals

• marinas

• facilities that generate or store hazardous materials

• other land uses and activities as designated by individual review

The following land uses and activities are not normally considered hotspots:

• residential streets and rural highways

• residential development

• institutional development

• commercial and office developments

• non-industrial rooftops

• pervious areas, except golf courses and nurseries

The applicant may use structural BMPs within drinking water source protection

areas for community public water systems only to the extent that the structural

BMP(s) does not cause contaminants in the recharge waters to impact the

ground water quality at levels that would cause an exceedance of the drinking

water Maximum Contaminant Levels (OAC Section 3745-81 and 3745-82). To

obtain a map of drinking water source protection areas for community public

water systems contact Ohio EPA’s Division of Drinking and Ground Waters at

(614) 644-2752.

Linear transportation projects which are caused solely by correcting safety related

issues, mandates of modern design requirements and/or resulting from other

mitigation activities are exempt from Groundwater Recharge Mitigation (Appendix

B, A.8) if less than one acre of total new right-of-way is associated with the project.

Protection of open space (infiltration areas) shall be by binding conservation

easements that identify a third-party management agency, such as a

Page 51 of 61

Ohio EPA Permit No.: OHC000006

homeowners’ association/condominium association, political jurisdiction or third-

party land trust.

A.8 Groundwater Recharge Mitigation.

If the post-development recharge volume is less than the pre-development recharge

volume, then mitigation will be required. Two options are available for most applications:

i. The preferred method is to convert additional land to land use with higher

recharge potential. The difference in groundwater recharge between the

existing and converted land use recharge is the amount which can be

used as recharge credit. Off-site Groundwater Recharge Mitigation shall

occur within the same Watershed Assessment Unit (12-digit HUC scale)

as the permitted site and preferably up-gradient and within a 2-mile

radius.

Mitigation shall be protected in perpetuity by binding conservation

easements or environmental covenants which must be recorded within 6

months of receiving permit authorization. Granting of binding

conservation easements or environmental covenants protected in

perpetuity for land outside of the disturbed area, but within a required

riparian setback counts towards required mitigation. Mitigation may also

be satisfied by approved pooled mitigation areas and in-lieu fee