COMPENDIUM OF MS4
PERMITTING APPROACHES
Photo credit: Alisha Goldstein, EPA
PART 3: WATER QUALITY-BASED REQUIREMENTS
SEPA
Office of Wastewater Management
Water Permit Division
April 2017
EPA-830-S-17-001

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Water Quality-Based Requirements
This compendium serves as a snapshot of MS4 permit provisions focused on water quality-
based requirements for specific pollutant parameters that are consistent with approved TMDLs.
It also includes provisions to protect impaired waters prior to TMDL development or to achieve
other water quality objectives, such as protecting high quality waters. To develop this
compendium, EPA reviewed all state and EPA-issued individual and general small MS4 final
permits issued up to January 2017 and compiled examples of permit language. This
compendium provides examples of permit language for permitting authorities' consideration as
they undertake implementation of the General Permit Remand Rule, particularly with respect
to establishing permit terms and conditions that are "clear, specific, and measurable." These
permit excerpts are intended to help permitting authorities develop appropriate permit terms
and conditions, and do not address compliance with the procedural and other requirements of
the General Permit Remand Rule.
The review of existing state and EPA permits for this compendium identified different ways of
implementing TMDLs through quantitative requirements or pollutant-specific management
measures, or a combination of both. EPA also reviewed MS4 permits to glean examples of how
permitting authorities measured progress of implementation of water quality-based
requirements through review and approval of implementation plans, monitoring and modeling,
and reporting requirements. Finally, EPA reviewed MS4 permits for water quality-based
requirements related to discharges to impaired waters without approved TMDL(s).
Overall, EPA found that nearly all MS4 permits include at least some language addressing
impaired waters. For the purposes of presenting the different permitting approaches found in
EPA's permit review, this compendium organizes the examples into the following categories:
1.	Listing of applicable TMDLs, Wasteload Allocations (WLAs), and/or the affected MS4s
2.	Numeric limits and other quantifiable approaches for the specific pollutants of concern1
3.	Required implementation of specific stormwater controls or management measures
4.	Other types of water quality-based requirements
a.	Permitting Authority Review and Approval of TMDL Plans
b.	Monitoring & Modeling Requirements
c.	TMDL-Related Annual Reporting Requirements
5.	Requirements for discharges to impaired waters prior to TMDL approval
EPA notes that this compendium is intended to serve as a snapshot of existing permit
provisions. EPA anticipates that as permits are reissued in the coming months and years, the
information in this compendium will need to be updated to include newer examples or
1 The use of the term pollutant of concern in this compendium refers to the pollutant parameter(s) for which a
waterbody is listed as impaired under section 303(d) of the Clean Water Act or for which a TMDL has been
approved or established by EPA.
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Water Quality-Based Requirements
modified information. EPA has an interest in ensuring the accuracy of the information
contained in this document, and therefore welcomes input on any aspect of this compendium
at any time.
The Agency will update the compendium as needed based on comments received and new
information. EPA notes that the inclusion of any particular permit example should not be read
as an Agency endorsement of the entire approach taken in that permit, nor should it be read as
EPA's independent determination that the permit terms meet the regulatory requirements.
This includes the permit standard for regulated small MS4s "to reduce the discharge of
pollutants from [the] MS4 to the maximum extent practicable, to protect water quality, and to
satisfy the appropriate water quality requirements of the Clean Water Act" 40 CFR 122.34(a).
In addition, this document does not contain or impose any legally binding requirements on EPA,
states, or the regulated community, and does not confer legal rights or impose legal obligations
upon any member of the public. EPA made every attempt to ensure the accuracy of the
examples included in this document; however, in the event of a conflict between this
compendium and any statute, regulation, or permit, the statute, regulation or permit controls.
For more information about the NDPES Stormwater Program visit
www.epa.gov/npdes/stormwater.
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Contents
1	LISTING OF TMDLS, WLAS, AND THE AFFECTED MS4S	1
GENERAL PERMITS	2
California	2
Massachusetts	2
Minnesota	2
New Hampshire	2
Pennsylvania	2
Washington	2
INDIVIDUAL PERMITS	3
Anchorage, AK	3
Menomonee Watershed, Wl	3
Prince George's County, MD	3
Portland, OR	3
2	NUMERIC LIMITS FOR POLLUTANTS OF CONCERN	4
GENERAL PERMITS	5
California	5
Virginia	6
Massachusetts	7
New Hampshire	8
Pennsylvania	9
New York	9
Middle Rio Grande Watershed, NM	10
INDIVIDUAL PERMITS	11
Arlington County, VA	11
Lake Tahoe, CA	11
Los Angeles County, CA	12
North Orange County, CA	13
San Diego, CA	13
San Francisco Bay Region, CA	14
Prince George's County, MD	14
Honolulu, HI	15
Washington, DC	15
New Castle County, DE	16
3	SPECIFIC CONTROL MEASURES FOR POLLUTANTS OF CONCERN	17
GENERAL PERMITS	18
Pennsylvania	18
Massachusetts	18
New Hampshire	19
Washington	19
Connecticut	20
New York	20
INDIVIDUAL PERMITS	21
Washington, DC	21
Denver, CO	22
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Contents
Florida Phase I MS4 Permits	22
San Francisco Bay Region, CA	23
4 OTHER TYPES OF WATER QUALITY-BASED REQUIREMENTS	24
GENERAL PERMITS	25
4.1	PERMITTING AUTHORITY REVIEW AND APPROVAL OF TMDL PLANS	25
Vermont	25
Pennsylvania	25
Virginia	26
Georgia	27
Minnesota	27
California	28
New York	28
Wisconsin	28
INDIVIDUAL PERMITS	29
Arlington County, VA	29
Denver, CO	29
Los Angeles Country, CA	30
Montgomery County, MD	31
Prince George's Country, MD	31
Washington, DC	31
Portland, OR	31
4.2	MONITORING & MODELING REQUIREMENTS	32
GENERAL PERMITS	32
California	32
Georgia	33
Washington	33
Connecticut	33
Tennessee	33
INDIVIDUAL PERMITS	34
Atlanta, GA	34
Nashville, TN	34
Florida Phase I Permits	35
Prince George's County, MD	35
Tucson, AZ	35
4.3	TMDL-RELATED ANNUAL REPORTING REQUIREMENTS	36
GENERAL PERMITS	36
Arkansas	36
California	36
Georgia	36
Minnesota	37
INDIVIDUAL PERMITS	37
Prince George's Country, MD	37
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Contents
5 DISCHARGES TO IMPAIRED WATERS PRIOR TO TMDL APPROVAL	38
GENERAL PERMITS	39
Arkansas	39
California	39
Georgia	40
Massachusetts	41
New Hampshire	41
INDIVIDUAL PERMITS	41
Baton Rouge, LA	41
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1 Listing of TMDLs, WLAs, and the Affected MS4s
A
first step in determining
whether additional
permit requirements are
necessary as a result of an
approved or established
TMDL is to establish whether
any TMDLs or WLAs apply to
the MS4s being permitted.
Although many permits have
placed the responsibility for
making this determination on
the MS4 permittee, several
permits have instead
included information on which TMDLs and WLAs apply and which MS4s
are affected directly in the permit. This approach reduces the amount
of work required of the permittee in interpreting TMDL documents, and
provides greater clarity for the permittee in understanding what water
quality-related requirements may apply. The following are examples of
this approach.
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1 Listing ofTMDLs, WLAs, and the Affected MS4s
General Permits
California
The 2013 California small MS4 permit includes tables showing applicable TMDLs, the MS4s
covered by WLAs, the applicable WLA, and individualized TMDL implementation requirements
for each affected MS4. See Attachment G.
Massachusetts
The 2016 (Effective 2017) Massachusetts small MS4 general permit identifies in Part 2.2.1 the
list of municipalities subject to nine different TMDLs, including TMDLs in other states that are
impacted by municipalities in Massachusetts.
Minnesota
The Minnesota Pollution Control Agency (MPCA) includes on its website the Master List MS4
Permit TMDLs Spreadsheet that identifies TMDLs and associated WLAs that apply to its
regulated MS4s. See "Application Items" under the Permit tab.
New Hampshire
The 2017 (Effective 2018) New Hampshire small MS4 general permit identifies in Part 2.2.1 the
list of municipalities subject to approved TMDLs for chlorides, bacteria, pathogens, and
phosphorus.
Pennsylvania
The 2016 (Effective 2018) Pennsylvania small MS4 general permit identifies two "MS4
Requirements Tables" for municipal MS4s and non-municipal MS4s that identify, for each MS4
subject to the permit, the impaired waters to which they discharge, the permit appendix that
applies to them (separate appendices address metals, pathogens, PCBs, Chesapeake Bay
watershed, and waters impaired for nutrients and/or sediment), and any other causes of
impairment.
Washington
The 2013 Western Washington small MS4 permit identifies each TMDL within the permit area
and all affected MS4 permittees. See Appendix 2.
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1 Listing ofTMDLs, WLAs, and the Affected MS4s
Individual Permits
Anchorage, AK
The 2015 Anchorage. Alaska. MS4 permit includes in Table 2 (Part 1.4.4) a list of impaired
receiving waters within the municipality's jurisdiction that includes both completed TMDLs and
impaired waters without TMDLs. The table identifies the pollutants of concern and receiving
waters.
Menomonee Watershed, Wl
The 2012 Menomonee Watershed Permit for Milwaukee, Wisconsin, and 10 other MS4
permittees includes a table that lists all of the impaired waterbodies in the Menomonee River
Watershed, the pollutants of concern, and the contributing MS4. See Table 1.
Prince George's County, MD
The 2014 Prince George's County. Maryland. MS4 permit provides an attachment, which
includes a three-page list of EPA-approved TMDLs in the County. See Attachment B.
Portland, OR
The 2011 City of Portland and Port of Portland MS4 permit lists on the cover page that WLAs
are included for urban stormwater for the Willamette River Basin, Columbia River Basin,
Tualatin River Sub-basin, and the Columbia Slough.
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2 Numeric Limits for Pollutants of Concern
P everal MS4 permits include numeric water quality-based
requirements for specific pollutant parameters that are consistent
with approved Total Maximum Daily Loads (TMDLs). These permits
often combine numeric limitations with specific control measure
requirements. Examples of such MS4 permits are included n this
section.
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2 Numeric Limits for Pollutants of Concern
General Permits
California
The 2013 California general permit for discharges from
small MS4s incorporates numeric WLAs that apply to
individual permittees.
See Attachment G. For example, for the Pajaro River
sediment TMDL, four MS4 permittees are prohibited from
discharging sediment to the listed waterbodies in excess of
the WLAs shown in the Table below. The allocations
represent a 90% reduction in sediment loading to each
waterbody from urban roads. The permit implements
numeric WLAs by also requiring near-term actions, in the
form of specific management measures, which constitute
the bulk of what the permittee must do to be consistent
with the WLAs. These requirements are individualized for
each pollutant of concern, impaired watershed and
contributing MS4 discharger. For example, for the Napa
River pathogens WLA for municipal stormwater, the permit
requires the six affected MS4s to educate the public about
pathogen impacts and ways to reduce pathogen
discharges, and to develop and implement programs to
reduce/eliminate fecal coliform loading from pet wastes,
among other requirements.
The blue boxes accompanying each
example provide a list of pollutants
with numeric limits or other
quantifiable approaches consistent
with the approved TMDLsfor each
identified MS4 permit
2013 CA MS4 General Permit
- Pollutants with Numeric
Limits
•	Sediment
•	Pathogens
•	Nitrogen
•	Phosphorus
•	Pesticides (Diazinon,
Chlorpyrifos)
•	Methyl-mercury
•	Dissolved Oxygen
•	Metals (Cu, Pb, Zn)
Pajaro River TMDL WLA and LA for Sediment2
Applicable MS4s
Major Subwatershed
Metric Tons of Sediment Per Year
City of Morgan Hill
City of Gilroy
City of Hollister
City of Watsonville
Tres Pinos
1
San Benito
100
Llagas
787
Uvas
139
Upper Pajaro
161
Corralitos
284
Mount of Pajaro River
191
2 CA Phase II Small MS4 General Permit. Appendix G.
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2 Numeric Limits for Pollutants of Concern
Virginia
The 2013 Virginia general permit for discharges from small
MS4s requires permittees discharging to the Chesapeake Bay
watershed to reduce loadings of nitrogen, phosphorus, and
total suspended solids from existing developed lands (pre-
June 30, 2009) by 5% of its total load reduction by the permit
expiration date. The permit also requires a 5% offset of
increased loads from new and grandfathered construction
projects disturbing one or more acres for which an average
land cover condition greater than 16% impervious cover was
used in the design of post-development stormwater facilities.
The general permit includes tables with loading rates and
reduction rates to be used by the permittee to calculate
required 5% load reductions from existing sources. Load
reductions are to be accomplished through the
implementation of a Chesapeake Bay TMDL Action Plan that
outlines the means and methods by which the permittee will
achieve the required reductions. For this permit term, the
permit states that compliance with these requirements
"represents adequate progress for this state permit term
towards achieving TMDL WLAs consistent with the
assumptions and requirements of the TMDL." See Sections
I.C, I.C.2.a.5, Tables 3.a-3.d, I.C.2.a.7 and 8, and I.C.3. In the
Watershed Implementation Plan for the Chesapeake Bay
TMDL, Virginia committed to a phased approach to reducing
nitrogen, phosphorus, and TSS from the MS4 and will include
additional loading reductions in the next two permits terms.
2013 VA MS4 General Permit
- Pollutants with Numeric
Limits
•	Nitrogen
•	Phosphorus
•	Sediment
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2 Numeric Limits for Pollutants of Concern
Massachusetts
The 2016 (Effective 2017) Massachusetts small MS4 general
permit, in Appendix F, identifies specific load reductions,
milestones, and completion dates for individual permittees for
the Charles River Phosphorus TMDL and the Lake and Pond
Phosphorus TMDLs. For example, the table below illustrates the
phosphorus reductions for several permittees in the Charles River
Watershed.


2016 (Effective 2017) MA

MS4 General Permit

- Pollutants with Numeric

Limits

• Phosphorus


-J
Annual Stormwater Phosphorus Load Reduction by Permittee, Charles River Watershed
Community
Baseline
Phosphorus
Load, kg/yr
Stormwater
Phosphorus Load
Reduction
Requirement kg/yr
Allowable
Phosphorus
Load, kg/yr
Stormwater Percent
Reduction in
Phosphorus Load (%)
Arlington
106
57
49
53%
Ashland
67
23
44
34%
Bellingham
947
331
616
35%
Belmont
202
86
116
42%
Brookline
1,635
789
846
48%
Cambridge
512
263
249
51%
Dedham
805
325
480
40%
Dover
831
137
694
17%
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2 Numeric Limits for Pollutants of Concern
New Hampshire
The 2017 (Effective 2018) New Hampshire small MS4 general
permit, in Appendix F, identifies percentage load reductions for
individual MS4s subject to an approved phosphorus TMDL to be
consistent with the assumptions and requirements of the
applicable WLA, as shown in Table below. Appendix F also
includes detailed methods and annual phosphorus load export
rates for measuring load reductions for various stormwater BMPs treating runoff from different
site conditions (i.e., impervious or pervious) and land uses (e.g., commercial, industrial,
residential, etc.). The estimates of annual phosphorus loads and load reductions due to BMPs
are intended for use by MS4 operators to measure compliance with their respective
phosphorus reduction requirements.
Waterbodies and Primary Municipalities subject to a Lake or Pond Phosphorus TMDL
Towns
Water Body name
% Reduction in TP Load
for All Sources
TMDL
Amherst; Merrimack
Baboosic Lake
44%
Baboosic TMDL
Merrimack
Horseshoe Pond
76%
Horshoe TMDL
Manchester
Nutt Pond
71 %
Nutt TMDL
Manchester
Pine Island Pond
64%
Pine Island TMDL
Hudson
Robinson Pond
48%
Robinson TMDL
Bedford
Sebbins Pond
64%
Sebbins TMDL
Sandown
Showell Pond
69%
Showell TMDL
Manchester
Stevens Pond
50%
Stevens TMDL
Derry
Hoods Pond
76%
Hoods TMDL
Kingston
Halmoon Pond
74%
Halfmoon TMDL
Kingston
Greenwood Pond
69%
Greenwood TMDL
Hollis
Flints Pond
40%
Flints TMDL
Manchester
Dorrs Pond
62%
Dorrs TMDL
Kingston; Newton
Country Pond
52%
Country TMDL
Raymond
Governors Lake
47%
Governors TMDL
Bedford
Sandy Pond
51 %
Sandv TMDL
r
2017 (Effective 2018) NH
MS4 General Permit
- Pollutants with Numeric
Limits
• Phosphorus
'	<
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2 Numeric Limits for Pollutants of Concern
Pennsylvania
The 2016 (Effective 2018) Pennsylvania small MS4 general
permit requires, for MS4s discharging to waters within the
Chesapeake Bay, that pollutant load reductions (lbs/year) be
achieved within 5 years of permit coverage. The MS4s is
required to identify pollutant reductions in a Pollutant
Reduction Plan, with minimum percent reductions of 10%
for pollutant loadings of sediment, 5% for pollutant loadings
of Total Phosphorus and 3% pollutant loadings of Total
Nitrogen. See Appendix D. Similar loading reductions are
required in Appendix E for discharges to waters impaired by
sediment or Total Phosphorus outside of the Chesapeake
Bay watershed.
New York
The 2015 New York small MS4 general permit in Part IX includes
pollutant load reductions for specific watersheds. Each
watershed includes deadlines for the development of a
watershed improvement strategy, retrofit plan, and pollutant
load reduction. An example from the permit for several
watersheds is below.
C	
2016 (Effective 2018) PA MS4
General Permit
- Pollutants with Numeric
Limits
•	Nitrogen
•	Phosphorus
•	Sediment
I	
2015 NY MS4 General Permit
- Pollutants with Numeric
Limits
•	Phosphorus
•	Pathogen
•	Nitrogen
Pollutant Load Reduction and Timetable for Pathogen Impaired Watershed Improvement
Strategy Areas - NY Small MS4 Permit.
Watershed
Watershed
Improvement
Strategy Deadline
Retrofit Plan
Submission
Deadline
Pollutant Load
Reduction (Waste
Load Allocation %)
Pollutant Load
Reduction Deadline
Richmond Creek
05/01/2013
09/30/2012
71
09/30/2022
Deep Hole Creek
05/01/2013
09/30/2012
29
09/30/2022
James Creek
05/01/2013
09/30/2012
51
09/30/2022
Flanders Bay
05/01/2012
03/09/2012
98
03/09/2021
Reeves Bay
05/01/2012
03/09/2012
97
03/09/2021
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2 Numeric Limits for Pollutants of Concern
Middle Rio Grande Watershed, NM
The 2014 Middle Rio Grande Watershed MS4 permit includes
approved TMDL tables in Appendix B with flow conditions and
associated WLAs for the 2010 bacteria TMDL for two stream
segments, as provided below, and with determinations for
calculating quantifiable WLAs for E. coli. The appendix also
provides a mechanism to calculate, based on acreage within a
drainage area, a target loading value for a particular monitoring
location by determining the base loading for subwatershed
areas consistent with the TMDL, setting subwatershed targets,
and ensuring overall compliance with the TMDL WLA
allocation.
TMDL Waste Load Allocations (WLAs)2 for E. coli: Rio Grande1
Stream
Segment
Stream Name
Permittee
Class
FLOW CONDITIONS & ASSOCIATED
WLA (cfu/day)3
High
Moist
Mid-
Range
Dry
Low
2105_50
Isleta Pueblo boundary to
Alameda Street Bridge (based
on flow at USGS Station
NM08330000)
Class A4
3.36
x1010
8.41
x1010
5.66
x1010
2.09
x1010
4.67
x109
Class B5
Class C6
3.73
x109
9.35
x109
6.29
x109
2.32
x109
5.19
x108
2105.1_00
non-Pueblo Alameda Bridge to
Angostura Diversion (based on
flow at USGS Station
NM08329928)
Class A
5.25
x1010
1.52
x1010
-
5.43
x109
2.8
x109
Class B
Class C
2.62
x1011
7.59
x1010
-
2.71
x1010
1.40
x1010
1	Total Maximum Daily Load for the Middle Rio Grande Watershed, NMED, 2010.
2	The WLAs for the stormwater MS4 permit was based on the percent jurisdiction area approach. Thus, the MS4 WLAs area
percentage of the available allocation for each hydrologic zone, where the available allocation = TMDL - WLA - MOS.
3	Flow conditions relate to percent of days the flow in the Rio Grande at a USGS Gauge exceeds a particular level: High 0-10%;
Moist 10-40%; Mid-Range 40-60%; Dry 60-90%; and Low 90-100% (Source: Figures 4.3 and 4.4 in 2010 Middle Rio Grande TMDL)
4	Phase II MS4s
5	Phase II MS4s (2000 Census)
6	New Phase II MS4s (2010 Census or MS4s designated by the Director)
2014 Middle Rio Grande
Watershed MS4 Permit
- Pollutants with Numeric
Limits
• Bacteria
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2 Numeric Limits for Pollutants of Concern
Individual Permits
Arlington County, VA
The 2013 Arlington County. Virginia. MS4 permit has the
same pollutant reduction requirements for nitrogen,
phosphorus, and TSS as the 2013 Virginia small MS4 general
permit (described above). The Arlington County MS4 permit
also requires the permittee to identify and submit to the
state at least seven retrofit projects within its watershed
retrofit plans that will be implemented within County
rights-of-way or on County property within 60 months of
permit issuance. The MS4 is also required to:
•	Plant a minimum of 2,000 trees on County lands and develop a program to distribute
a minimum of 2,000 trees to private property owners.
•	Have funding to accommodate a minimum of 200 participants in the StormwaterWise
Landscape program, which provides cost-sharing and technical assistance for the
installation of small-scale best management practices (BMPs) to reduce stormwater
runoff from private properties.
See Parts I.B.2.C and I.D.l.b.
Lake Tahoe, CA
The 2011 Lake Tahoe. California. MS4 permit, covering the
City of South Lake Tahoe, and portions of El Dorado County
and Placer County in the Lake Tahoe Hydrologic Unit,
requires each permittee to reduce fine sediment particle
(FSP), TP and total nitrogen (TN) loads by 10%, 7%, and 8%,
respectively, by September 30, 2016. These percentage
reduction requirements were applied to each of the
permittee's baseline load of FSP, TP, and TN to determine
the maximum load allowance for each permittee to meet
the 5-year load reduction requirements. See Section IV.B
and Table IV.B.l.
	
2013 Arlington, VA MS4
Permit
- Pollutants with Numeric
Limits
•	Nitrogen
•	Phosphorus
•	Sediment
2011 Lake Tahoe, CA
MS4 Permit
- Pollutants with Numeric
Limits
•	Fine Sediment Particles
•	Phosphorus
•	Nitrogen
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2 Numeric Limits for Pollutants of Concern
Los Angeles County, CA
The 2012 (Amended 2016) Los Angeles County. California,
systemwide permit requires permittees to comply with numeric
WQBELs based on WLAs in approved TMDLs. The permit includes
comprehensive provisions to achieve WLAs from applicable TMDLs,
including interim and final WQBELs and corresponding compliance
schedules consistent with the state-adopted TMDL Implementation
Plan, compliance monitoring, and reporting requirements, and for
each pollutant of concern. For example, Attachment L of the permit
prescribes final and interim WQBELs that apply to MS4s discharging
to the Santa Clara River. The attachment includes WQBELs for
nitrogen, chloride, trash, and E. coli that are consistent with the
WLAs from approved TMDLs for the Santa Clara River watershed.
For the interim WQBELs, the permit includes several alternatives
from which the permittees can choose to demonstrate compliance.
A permit can demonstrate compliance with the applicable interim
WQBEL in any of the following ways:
•	There are no violations of the interim WQBEL for the
pollutant of concern at the permittee's applicable MS4
outfalls;
•	There are no exceedances of the applicable receiving water
limitation for the pollutant of concern in the receiving
water at or downstream of the permittee's outfalls;
•	There is no direct or indirect discharge from the permittee's MS4 to the receiving
water subject to the interim WQBEL and/or the receiving water limitation for the
pollutant of concern;
•	The permittee has submitted and is fully implementing an approved Watershed
Management Program (WMP) or an Enhanced Watershed Management Program
(EWMP), which requires among other things that the permittee include multi-benefit
regional projects that retain through infiltration or capture and reuse the stormwater
volume from the 85th percentile, 24-hour storm for the drainage areas tributary to
these projects.
See Parts VI.C and E, and Attachments L - R.
2012 (Amended 2016) LA
County, CA MS4 Permit
- Pollutants with Numeric
Limits
•
Nitrogen
•
Chloride
•
Trash
•
Bacteria
•
Marine debris
•
DDTs and PCBs
•
Phosphorus
•
Toxics
•
Metals
•
Pesticides
•
Selenium
•
Mercury
•
Sediment
•
PAHs
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2 Numeric Limits for Pollutants of Concern
North Orange County, CA
The 2009 Orange County, California, MS4 permit establishes a
number of different numeric water quality-based requirements
that affect MS4s discharging to certain watersheds. For
instance, for MS4s discharging to the Newport Watershed, the
permit requires compliance with WLAs for metals (cadmium,
copper, lead, zinc, mercury, and chromium), organochlorine
compounds, and selenium. See Section XVIII.B.4. Note that the
original TMDLs for these constituents included no
implementation plans or compliance schedules for attainment.
During development of the modified TMDL, which will include
an implementation plan, the permittees are required to
continue working towards meeting the WLAs. In addition, for
TMDLs with implementation plans, the permit includes WLAs
that are required to be met as soon as 2013 (e.g., recreational
standards for fecal coliform), but by no later than 2019
(e.g., shellfish standards for fecal coliform). See Section XVIII.C. Other numeric WLAs are required in
Section XVIII.D for diazinon, chloropyrifos, TN, TP, and sediment. Compliance with the WLAs is to
be determined by receiving water monitoring. Where monitoring reveals that the WLAs are
exceeded, the permittees are required to evaluate and submit to the permitting authority within
12 months of the exceedances a proposal for implementing additional BMPs. See Section XVIII.E.
San Diego, CA
The 2013 San Diego Regional MS4 permit contains numeric
effluent limitations for diazinon, dissolved copper, TN, TP, lead,
zinc, and indicator bacteria, which are consistent with
applicable TMDL WLAs. The permit identifies for each
applicable TMDL information about the TMDL (waterbodies,
adoption dates); which MS4 co-permittees are affected; final
compliance requirements (final compliance dates, receiving
water and/or effluent limitations, BMP requirements, and final
TMDL compliance determination); interim compliance
requirements; and specific monitoring and assessment
requirements. See Attachment E.
2009 Orange County, CA
MS4 Permit
- Pollutants with Numeric
Limits
•	Metals
•	Organochlorine
Compounds (DDT, PCBs,
Chlordane, Dieldrin)
•	Selenium
•	Sediment
•	Fecal Coliform
•	Diazinon and Chlorpyrifos
•	Nutrients
2013 San Diego, CA MS4
Permit
- Pollutants with Numeric
Limits
•	Diazinon
•	Metals (Cu, Pb, Zn)
•	Nitrogen
•	Phosphorus
•	Bacteria
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2 Numeric Limits for Pollutants of Concern
San Francisco Bay Region, CA
The 2015 San Francisco Municipal Regional Stormwater Permit
requires the permittees to implement programs to address
pesticides toxicity, trash, mercury, PCBs, copper, and bacteria.
For pesticides toxicity, mercury, PCBs and bacteria, specific TMDL
WLAs are included. For trash, load reduction control actions are
required to reduce trash loads from the MS4 by 70% by 2017 and
80% by 2019; these requirements are based on the permitting
authority's best professional judgment in implementing a
narrative water quality objective absent a TMDL. See Provision
C.10. The permit also includes various specific control measures
for copper.
2015 San Francisco, CA
MS4 Permit
- Pollutants with Numeric
Limits
•	Trash
•	Mercury
•	PCBs
•	Pesticides
•	Bacteria
Prince George's County, MD
The 2014 Prince George's County. Maryland. MS4 permit requires the County to develop a work
plan within one year to address the Anacostia Trash TMDL, which estimates that 170,628
pounds of trash will need to be removed annually. The work plan must include a detailed
schedule, trash reduction benchmarks in years two and four, and methods of implementation.
The County must also develop accounting methods to quantify annual trash reductions.
The permit also requires restoration plans for waters with approved TMDLs. The restoration
plans must address the stormwater WLA for all EPA-approved TMDLs in the County. An annual
TMDL assessment report is required to be submitted to the permitting authority. In addition,
the permit requires the County, within the 5-year permit term, to achieve reductions in
discharges consistent with the Chesapeake Bay TMDL by restoring 20% of the previously
developed impervious land with little or no controls. See similar requirements in the 2014 Anne
Arundel County. Maryland. MS4 permit (Parts IV.E.2.a and VI.A).
Note that Maryland has five other Phase I MS4 permits [Charles
County (2014), Carroll County (2014), Frederick County (2014),
Harford County (2014), and Howard County (2014)] that are
required to restore 20% of the County's impervious surface area
based on the Maryland Department of Environment's 2014
Guidance "Accounting for Stormwater Wasteload Allocation and
Impervious Acres Treated." The permit further requires
monitoring to determine the effectiveness of the restoration
efforts toward achieving water quality.
See Parts IV.D.4, IV.E, and VI.A. See similar requirements in Parts
IV.E and VI of both the 2013 Baltimore County. Maryland. MS4
permit and the 2013 Baltimore City. Maryland. MS4 permit.
2014 Prince George's
MD MS4 Permit
- Pollutants with Numeric
Limits
•	Trash/Debris
•	Nitrogen
•	Phosphorus
•	Sediment
•	Bacteria
•	Mercury
•	PCBs
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2 Numeric Limits for Pollutants of Concern
Honolulu, HI
The 2015 Honolulu City/County MS4 permit requires
compliance with the "urban source wasteload allocation"
based on different TMDLs in table format including applicable
allocations; existing loads; and reductions needed for TN, TP,
and TSS. See Sections F.3.b and F.3.b.l through F.3.b.6.
2015 Honolulu, HI MS4
Permit
- Pollutants with Numeric
Limits
•	Nitrogen
•	Phosphorus
•	Sediment
Washington, DC
The 2011 DC MS4 permit requires the permittee to remove
103,188 pounds of trash annually. Reductions must be made
through a combination of the following approaches:
•	Direct removal from waterbodies (e.g., stream
cleanups, skimmers)
•	Direct removal from the MS4 (e.g., catch basin
cleanout, trash racks)
•	Direct removal prior to entry to the MS4 (e.g., street sweeping)
•	Prevention through additional disposal alternatives (e.g., public trash/recycling
collection)
•	Prevention through waste reduction practices, regulations, and/or incentives
(e.g., bag fees)
See Section 4.10.
2011 Washington, DC MS4
Permit
- Pollutants with Numeric
Limits
• Trash
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2 Numeric Limits for Pollutants of Concern
New Castle County, DE
The 2013 New Castle County/Delaware Department of
Transportation Individual Phase I MS4 permit includes in
Appendix A, WLAs assigned to the permittees for each
watershed. Annual baseline loads, annual TMDL loads, and
load reductions are included for each listed pollutant in each
watershed. An example for two waterbodies are included
below:
2013 New Castle County,
DE MS4 Permit
- Pollutants with Numeric
Limits
•	Nitrogen
•	Phosphorus
•	Bacteria
•	PCBs
•	Sediment
Wasteload Allocations Assigned to the New Castle County/DelDOT MS4
Waterbody
Pollutant
MS4 Wasteload Allocation Specified in Approved
TMDL
Annual Baseline
Load
Annual TMDL
Load
Load
Reduction
Appoquinimink River Dissolved
Oxygen and Nutrients (updated
Dec 2003) Bacteria (Dec 2006)
Total N
131,326 Ib/yr
70,251 Ib/yr
60%
Total P
23,300 Ib/yr
8,860 Ib/yr
60%
Bacteria
7.52E+12 CFU/yr
6.32+12 CFU/yr
15% (1)
7.03E+10 CFU/yr
6.06+10 CFU/yr
73% (2)
Army Creek
TMDL Analysis for the
Watersheds of Army Creek, Red
Lion Creek and Dragon Run
Creek, Delaware (August 2006)
Total N
14,782.5 Ib/yr
8.833 Ib/yr
40%
Total P
1241 Ib/yr
730 Ib/yr
40%
Bacteria
1.1E+13 CFU/hr
5.037E+12 CFU/yr
39%
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3 Specific Control Measures for Pollutants of Concern
EPA found several examples of permits that require their MS4
permittees to implement specific control measures or best
management practices (BMPs) to ensure consistency with the
applicable TMDLs. This approach provides both the permitting
authority and the permittee with measurable performance
measures that can be readily tracked, and it provides both parties
with the ability to understand what actions constitute reasonable
further progress towards achieving the TMDL and protecting water
quality.
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3 Specific Control Measures for Pollutants of Concern
General Permits
Pennsylvania
The 2016 (Effective 2018) Pennsylvania general permit for
discharges from small MS4s requires that permittees
implement pollutant control measures for waters impaired
by metals, pathogens, or priority organic compounds (see
Appendix A-C). For each of these pollutants, the permittee
is required to develop a sewershed map with outfalls that
discharge to the impaired water, an inventory of sources
of that pollutant in the sewersheds, and an investigation of
each suspected source. For pathogens, the permittee is
required to enact an ordinance that requires proper
management of animal wastes on property owned by the
permittee. See Appendix B.
The gray boxes provide a list of pollutants
for which the MS4 permit requires
implementation of specific control
measures consistent with approved
TMDLs.

2016 (Effective 2018) PA
MS4 General Permit

- Pollutants with specific
control measures

• Metals (Fe, Mn, Al)

• Acidity (Acid Mine
Drainage)

• Pathogens

• Priority Organic
Compounds (PCBs,
pesticides)



Massachusetts
The 2016 (Effective 2017) Massachusetts small MS4
general permit, in Appendix F, identifies enhanced best
management practice requirements for individual
permittees for each listed TMDL. For example, for MS4s in
one of the 16 approved bacteria or mixed pathogen
TMDLs (see Appendix F section A.Ill), the permit requires
enhanced public education measures (including annual
messages about proper management of pet waste) and
elevated priority ranking of catchments draining to
impaired waters for IDDE.
2016 (Effective 2017) MA
S
MS4 General Permit

- Pollutants with specific

control measures

• Bacteria or Mixed

Pathogen

• Nitrogen

• Phosphorus

• Metals (Cd, Pb, Al, Fe)



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3 Specific Control Measures for Pollutants of Concern
New Hampshire
The 2017 (Effective 2018) New Hampshire small MS4
general permit, in Appendix F. identifies specific actions
that individual permittees must take to address approved
TMDLs for chlorides and bacteria, and phosphorus. For
instance, among other requirements, affected MS4
operators are required to undertake as part of their
Chloride Reduction Plan the tracking of the amount of salt
applied to all municipally owned and maintained surfaces
and reporting of salt use using the UNH Technology
Transfer Center online tool, and to implement certain
planned activities, such as pre-wetting, pre-treating the
salt stockpile, increasing plowing prior to de-icing, and
monitoring of road surface temperatures. See Sections I
and II of Appendix F.
Washington
The 2013 Western Washington Phase II Municipal
Stormwater Permit includes tables that establish
additional watershed-specific actions that are required of
each named MS4. The actions are differentiated based on
the applicable TMDL and pollutant of concern. For
example, for the Stillaguamish River TMDL for fecal
coliform and dissolved oxygen, Appendix 2 lists the
permittees that the requirements apply to, and specific
actions. Some of these actions include inspections of
commercial animal handling and commercial composting
facilities at least every three years, installation of animal
waste collection stations at municipal parks, and screening
of all MS4 sub-basin outfalls for bacteria sources. See
Appendix 2.
r
2017 (Effective 2018) NH
MS4 General Permit
-1
- Pollutants with specific
control measures

• Bacteria or Pathogen

• Chloride

• Phosphorus

>—
—J
2013 Western WAMS4
General Permit
- Pollutants with specific
control measures
•	Bacteria
•	Dissolved oxygen
•	pH
•	Temperature
*	*
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3 Specific Control Measures for Pollutants of Concern
Connecticut
The 2016 (Effective 2017) Connecticut small MS4 general
permit requires that MS4s discharging to waters for which
nitrogen, phosphorus, or bacteria are stormwater
pollutants of concern to implement control measures,
screen outfalls and conduct monitoring. For example,
under the public education minimum control measure
(Section 6(a)(1)(C)), educational materials must be
specifically tailored and targeted to educate the public
about sources, impacts, and available pollution reduction
practices for sources of the pollutant of concern, such as
septic systems, fertilizer use, or grass clippings and leaves
management. See Section 6(k).
New York
The 2015 New York small MS4 general permit in Part IX
requires detailed controls to address specific impaired
waterbodies. For example, the New York City phosphorus
watershed strategy requires public education materials
that specifically address phosphorus by focusing on septic
systems as a source of phosphorus, phosphorus concerns
with fertilizer use, and phosphorus concerns with grass
clippings and leaves entering storm drains. Part IX.A also
requires inspection of on-site sanitary systems designed
for less than 1,000 gallons per day be inspected at least
once every five years.
r
¦"i
2016 (Effective 2017) CT
General Permit

= Pollutants with specific
control measures

• Phosphorus

• Nitrogen

• Bacteria

• Mercury


J
2016 NYMS4 General
Permit
- Pollutants with specific
control measures
•	Phosphorus
•	Bacteria
•	Nitrogen
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3 Specific Control Measures for Pollutants of Concern
Individual Permits
Washington, DC
The 2011 DC MS4 permit requires the permittee to
implement several different stormwater controls with
numeric targets:
- Pollutants with specific
control measures
•	Total organics
•	Nitrogen
•	Phosphorus
•	Sediment
•	Dissolved oxygen
•	Metals (As, Cu, Pb, Zn)
•	Oil & grease
•	PCB
•	Bacteria
2011 Washington, DC MS4
Permit
• Implement retrofits for stormwater discharges
from a minimum of 18,000,000 square feet of
impervious surfaces during the permit term. A
minimum of 1,500,000 square feet of this
objective must be in transportation rights-of-way;
• Achieve a minimum net annual tree planting rate
of 4,150 plantings annually within the DC MS4
area, with the objective of a District-wide urban
tree canopy coverage of 40% by 2035. The annual
total tree planting shall be calculated as a net
increase, such that annual mortality is also	
included in the estimate. Trees must be planted in
accordance with the Planting Specifications issued by the International
Society of Arboriculture as appropriate to the site conditions; and
• Install at a minimum 350,000 square feet of green roofs on District
properties during the term of the permit (including schools and school
administration buildings).
See Sections 4.1.5.4, 4.1.6.2, and 4.1.7.2.
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3 Specific Control Measures for Pollutants of Concern
Denver, CO
The 2009 Denver, Colorado, MS4 permit identifies specific
requirements that apply to discharges to Segment 14 of the Upper
South Platte River Basin associated with WLAs from the approved
E. coliTMDL. The permit requires the permittee to identify outfalls
with dry weather flows and to identify outfalls of concern; to
monitor priority outfalls of concern for flow rates and E. coli
densities; to implement a system maintenance program for listed
priority basins (which includes storm sewer cleaning and sanitary sewer investigations); to
install markers at least 90% of storm drain inlets in areas with public access; and to conduct a
public outreach program focused on sources that contribute E. coli loads to the MS4. See Part
I.B.l.f.
The permit also requires the permittee to develop and implement new programs and BMPs,
in addition to the activities described above, to reduce dry weather discharges of E. coli to the
extent necessary so that by the end of the compliance period, dry weather discharges from
MS4 outfalls of concern do not contribute to an exceedance of the E. coli standard (do not
exceed an E. coli density of 126 cfu per 100 ml for a geometric mean of all samples collected
at a specific outfall in a 30-day period). The permit includes a compliance schedule for
meeting this requirement by November 30, 2018. See Part I.B.l.f. Contact state for permit.
Florida Phase I MS4 Permits
Florida's Phase I MS4 permits require permittees that discharge
to waterbodies with an approved TMDL and a Basin
Management Action Plan (BMAP) to comply with the provisions
of the BMAP and report on the status of BMAP implementation
with each annual report. For waterbodies with an approved
TMDL, but no BMAP, the MS4 permittee is required to submit fc
review and approval a TMDL prioritization schedule within 6 months of the permit effective
date. At a minimum, the highest priority TMDL is to have a plan to address the pollutant of
concern by the end of the permit cycle. See, for example, Parts VIII. B.2 and B.3.a of the
Pinellas and Miami-Dade permits.
Florida's permits also include specific requirements for fecal coliform TMDL waters that do
not have a BMAP. In these cases, the MS4 permittee is required to develop and submit a
bacterial pollution control plan with specific elements such as bacteria source tracking and a
pet waste management program. The bacteria pollution control plan is to be implemented in
accordance with the schedule within the approved plan. The permittees are required to
submit a status report with each annual report. See, for example, Part VIII.B.4 of the Pinellas
and Miami-Dad permits. Contact state for permits.
2009 Denver, CO MS4
Permit
- Pollutants with specific
control measures
• Bacteria
FL Phase I MS4 Permit
- Pollutants with specific
control measures
• Bacteria
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3 Specific Control Measures for Pollutants of Concern
San Francisco Bay Region, CA
In addition to the numeric requirements for trash in the
2015 San Francisco Bay Regional Stormwater MS4 Permit as
described in Section 2 of this compendium, this permit
includes specific control measures that are required to
achieve water quality-based requirements for trash,
mercury, polychlorinated biphenyls, pesticides, copper,
polybrominated diphenyl ether, and selenium. The permit
requires interim milestones and pollutant-specific control
measures that are consistent with the implementation
actions identified in an applicable WLA. (For "urban
stormwater," see pages 15-16 of the Basin Plan
Amendments to the San Francisco Basin Water Quality
Control Plan). For example, the San Francisco Basin Water
Quality Control Plan for mercury includes interim and final milestones of 120 kilograms
per year (kg/yr) loading by February 2018 and 82 kg/yr by February 2028. The permit
incorporates both the aggregate WLA and the interim loading milestone, as well as
implementation requirements that are identified in the TMDL Implementation Plan,
including requirements to:
1.	Implement a mercury source control program;
2.	Implement a monitoring system to quantify mercury loads and loads reduced;
3.	Monitor methylmercury in discharges;
4.	Conduct a fate and transport study; and
5.	Develop an allocation sharing mechanism.
As another example, fecal indicator bacteria controls are required for San Pedro Creek
and Pacifica State Beach. The permit includes numeric targets for allowable exceedances
depending on dry or wet weather and frequency of sampling. The permit also requires
bacterial control strategies including inspections of commercial horse and dog kennel
facilities, installation of new dog waste clean-up signs and bag dispensers, and enhanced
pet waste public outreach.
See Sections C.9 through C.14.
2015 San Francisco Bay
Regional MS4 Permit
- Pollutants with specific
control measures
•	Mercury
•	Copper
•	Trash
•	PCBs
•	Bacteria
•	Pesticides
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4 Other Types of Water Quality-Based Requirements
A
/ \ number of permits
exhibit alternative
means of ensuring
consistency with
applicable TMDLs, other
than by adopting
numeric requirements
or implementing specific
stormwater controls. Permitting authorities measure the progress of
implementing water quality-based requirements through review and
approval of implementation plans, as well as the use of monitoring
and modeling provisions, and reporting requirements. The following
permitting approaches are illustrative of these types of requirements.
4.1 Permitting Authority Review and Approval of TMDL Plans
Several permitting authorities require that their permittees develop a TMDL Plan
(or the TMDL component of the overall stormwater management program
document) and submit it for review and/or approval. The benefit of this type of
approach is that through the permitting authority review there is a level of assurance
that the proposed plan will be consistent with the assumptions and requirements of
any available WLA in an approved TMDL.
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4.1 Permitting Authority Review and Approval of TMDL Plans
General Permits
Vermont
The 2012 Vermont general permit for discharges from small MS4s requires permittees that
discharge to a stormwater-impaired water with an approved TMDL to submit, within 3 years of
the permit issuance date, a Flow Restoration Plan for state review and approval. The permit
specifies six elements that must be addressed in the Flow Restoration Plan (Sec. IV.C.1(e).
Pennsylvania
The 2016 (Effective 2018) Pennsylvania general permit for discharges from small MS4s requires
permittees discharging to impaired waters to submit a Pollutant Reduction Plan (PRP) with
their notice of intent (NOI) for review and approval by the permitting authority if the MS4 is in
the Chesapeake Bay or discharging to a nutrient or sediment impaired water. A PRP is a
planning document prepared by the permittee, which guides the selection and implementation
of specific BMPs to reduce pollutant loading to surface waters. The objective of a PRP is to
improve the condition of surface waters such that the waters eventually attain water quality
standards and its designated and existing uses in accordance with 25 Pa. Code Chapter 93. See
Part C.ll and Appendix D and E.
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4.1 Permitting Authority Review and Approval of TMDL Plans
Virginia
The 2013 Virginia general permit for discharges from small MS4s requires that permittees
discharging to the Chesapeake Bay watershed submit a Chesapeake Bay TMDL Action Plan
within 24 months of the permit effective date for review and approval by the permitting
authority. The Chesapeake Bay TMDL Action Plans must include the following:
•	A review of the current MS4 program to identify new or modified legal authorities to
meet these requirements;
•	An estimate of the annual pollutant of concern loads discharged from the existing
sources based loading rates specified in the permit;
•	A determination of the total pollutant load reductions necessary to reduce the annual
pollutant of concern loads from existing sources;
•	The management practices and retrofit programs that will be utilized to meet the
required load reductions and a schedule to achieve those reductions. The schedule
should include annual benchmarks to demonstrate the ongoing progress in meeting the
reductions; and
•	The means and methods to offset the increased loads from new sources that disturb
one or more acres as a result of the utilization of an average land cover condition
greater than 16% impervious cover for the design of post-development stormwater
management facilities. The permittee must use tables in the permit to develop the
equivalent pollutant load for nitrogen and TSS.
See Table 1 and Section I.C.2.
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4.1 Permitting Authority Review and Approval of TMDL Plans
Georgia
The 2012 Georgia general permit for discharges from small MS4s requires existing permittees
discharging to impaired waters with an approved TMDL to develop and submit for review and
approval to the permitting authority an Impaired Waters Plan (for MS4s with a population of
< 10,000) or a Monitoring and Implementation Plan (for MS4s with a population of > 10,000).
•	The Impaired Waters Plan, which must be submitted by a specific date, must include a
list of the impaired waters and the pollutant(s) of concern, a map showing the locations
of the impaired waters and all MS4 outfalls discharging to those waters, BMPs that will
be implemented to address each pollutant of concern, and a schedule for implementing
the BMPs.
•	The Monitoring and Implementation Plan, which also must be submitted by a specified
date, must identify where wet weather monitoring will occur, sample type, frequency,
schedule to begin monitoring, and a description of the BMPs that will be implemented
to address each pollutant of concern.
See Sections 4.4.1 and 4.4.2.
Minnesota
The 2013 Minnesota general permit for discharges from small MS4s requires each applicant to
submit its Stormwater Pollution Prevention Program (SWPPP) document to the permitting
authority, including a compliance schedule for addressing applicable WLAs with the following
required elements:
•	Interim milestones, expressed as BMPs or progress toward implementation of BMPs to
be achieved during the term of this permit
•	Dates for implementation of interim milestones
•	Strategies for continued BMP implementation beyond the term of this permit
•	Target dates the applicable WLA(s) will be achieved
See Sections II.D.6 and III.E.
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4.1 Permitting Authority Review and Approval of TMDL Plans
California
The 2013 California general permit for discharges from small MS4s requires some of its
permittees, for specific TMDLs (including for pathogens, sediment, temperature, and other
pollutants), to submit for review and approval a plan to minimize, control, and preferably
prevent the discharge of the pollutant of concern.
New York
The 2015 New York small MS4 general permit in Part III.B.2 requires MS4s in watersheds listed
in Appendix 2-10 to develop Watershed Improvement Strategies for eight different
watersheds, which are described in Part IX of the permit. Part IX lists, for each watershed,
specific deadlines for submission of the strategy, retrofit plan, and pollutant load reduction.
Wisconsin
The 2014 Wisconsin small MS4 general permit addresses TMDL requirements in Part 1.5. MS4s
discharging to impaired waters must submit to the State an updated storm sewer map showing
TMDL watershed boundaries, a tabular summary that shows the percent reduction needed to
comply with the WLA for each drainage boundary, and a written plan if tabular summary shows
applicable percent reductions is not being achieved. Guidance on MS4 modeling is available on
Wisconsin DNR's website.
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4.1 Permitting Authority Review and Approval of TMDL Plans
Individual Permits
Arlington County, VA
The 2013 Arlington County. Virginia. MS4 permit has the same requirement as the 2013 Virginia
small MS4 general permit to submit a Chesapeake Bay TMDL Action Plan within 24 months of
the permit effective date for review and approval by the permitting authority (described
above). See Part I.D.l.b. This same requirement is also in all of Virginia's Phase I MS4 individual
permits including 2014 Chesterfield County MS4 permit. 2014 Prince William County MS4
permit. 2015 Fairfax County MS4 permit. 2015 Henrico County MS4 permit. 2016 City of
Chesapeake MS4 permit. 2016 City of Hampton MS4 permit. 2016 City of Newport News MS4
permit. 2016 City of Norfolk MS4 permit. 2016 City of Portsmouth MS4 permit, and the 2016
City of Virginia Beach MS4 permit.
Denver, CO
The 2009 Denver, Colorado, MS4 permit identifies specific requirements that apply to
discharges to Segment 14 of the Upper South Platte River basin associated with WLAs from the
approved E. coliTMDL. The permit requires the permittee to submit to the state an E. coli
control plan, which, among other things, must include requirements for the permittee to
identify outfalls with dry weather flows and to identify outfalls of concern; to monitor priority
outfalls of concern for flow rates and E. coli densities; to implement a system maintenance
program for listed "priority basins" (which includes storm sewer cleaning and sanitary sewer
investigations); to install markers for at least 90% of storm drain inlets in areas with public
access; to conduct a public outreach program focused on sources that contribute E. coli loads to
the MS4; and to develop and implement additional programs and BMPs as necessary to ensure
that dry weather discharges from MS4 outfalls of concern by November 30, 2018, do not
contribute to an exceedance of the E. coli standard (do not exceed an E. coli density of 126 cfu
per 100 ml for a geometric mean of all samples collected at a specific outfall in a 30-day
period). See Part I.B.l.f. Contact state for permit.
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4.1 Permitting Authority Review and Approval of TMDL Plans
Los Angeles Country, CA
The 2012 (Amended 2016) Los Angeles County. California, systemwide permit provides
permittees with the option of demonstrating compliance with interim water quality-based
effluent limitations (WQBELs) by implementing a state-approved Watershed Management
Program (WMP) or Enhanced Watershed Management Program (EWMP). The permit specifies
what each WMP or EWMP must include to be approvable. For example, each EWMP must,
among other things:
•	Prioritize water quality issues resulting from stormwater/non-stormwater discharges to
the receiving water within each Watershed Management Area;
•	Identify and implement strategies, control measures, and BMPs to ensure that
discharges (1) achieve applicable WQBELs; (2) do not cause or contribute to
exceedances of receiving water limitations; and (3) do not include non-stormwater
discharges that are prohibited;
•	Demonstrate reasonable assurance (through a peer-reviewed quantitative modeling
approach) that implementation of the actions/projects proposed in the WMP or EWMP
will achieve WQBELs and receiving water limitations by required deadlines;
•	Execute an integrated monitoring program to determine progress towards achieving
applicable limitations and/or action levels;
•	Modify strategies, control measures, and BMPs as necessary based on analysis of
monitoring data to ensure applicable WQBELs and receiving water limitations and other
milestones are achieved in the required timeframes;
•	Include multi-benefit regional projects to ensure that MS4 discharges achieve
compliance with all final WQBELs and do not cause or contribute to exceedances of
receiving water limitations by retaining through infiltration or capture and reuse the
stormwater volume of the 85th percentile, 24-hour storm for the drainage areas
tributary to the multi-benefit regional projects; and
•	Maximize the effectiveness of funds through analysis of alternatives and section and
sequencing of actions needed to address human health and water quality-related
challenges and noncompliance.
The permittee is considered in compliance with the interim WQBELs if it:
•	Provides timely notice of its intent to develop a WMP or EWMP;
•	Meets all deadlines for development of the WMP or EWMP;
•	For the area covered by the program, targets implementation of watershed control
measures in its existing SWMP to address known contributions of pollutants from MS4
discharges that cause or contribute to exceedances of receiving water limitations;
•	Receives final approval of the WMP or EWMP;
•	Fully implements its approved WMP or EWMP, including all proposed actions/projects,
per the approved time schedules; and
•	Periodically adapts its WMP or EWMP, when necessary, if monitoring data indicate that
expected water quality outcomes are not being achieved.
See Parts VI.C and E, and Attachments L -R.
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4.1 Permitting Authority Review and Approval of TMDL Plans
Montgomery County, MD
The 2010 Montgomery County. Maryland. MS4 permit requires the permittee to submit to the
state for review and approval a plan for each EPA-approved TMDL for the portion of a
watershed covered by the permit. The plans must include the actions and deadlines to meet
the required pollutant load reduction benchmarks and WLAs within the specified timeframe.
See Part III.J.2.
Prince George's Country, MD
The 2014 Prince George's County. Maryland. MS4 permit requires the permittee to submit for
review and approval by the state a Restoration Plan for each WLA approved by EPA prior to the
permit's effective date. The permit requires that each Restoration Plan: (1) include the final
date for meeting applicable WLAs and a detailed schedule for implementing all structural and
nonstructural measures necessary for meeting applicable WLAs; (2) provide detailed cost
estimates for individual projects, programs, controls, and plan implementation; (3) evaluate
and track implementation of restoration plans toward meeting established benchmarks,
deadlines, and stormwater WLAs; and (4) develop an ongoing iterative process for focusing in
on areas where the WLAs are not being met according to benchmarks and deadlines
established as part of the County's watershed assessments. Note that in another section of the
permit, the County is required to specify pollutant load reduction benchmarks for each
watershed that demonstrate progress toward meeting all applicable stormwater WLAs. See
Sections III.E.l.b.v and E.2.
Washington, DC
The 2011 DC MS4 permit requires the permittee to submit for review and approval no later
than 30 months after the effective date of the permit modification a Consolidated TMDL
Implementation Plan to address all TMDL WLAs applicable to District waters, with a focus on
15 specific TMDLs affecting the MS4's discharge, but also to evaluate other pollutants of
concern for which relevant WLAs exist. Further, the permittee is required to submit an annual
updated Consolidated TMDL Implementation Plan to account for any new or revised TMDL
WLAs. See Section 4.10.
Portland, OR
The 2011 City of Portland and Port of Portland MS4 permit in Schedule D.3 requires the
permittee to develop a WLA Attainment Assessment for submittal to the State. The
assessment must include information on the type and extent of BMPs necessary to achieve
pollutant load reductions associated with the TMDL, and the financial costs and other resources
needed. The permittee is also required to submit to the State a TMDL Pollutant Load Reduction
Evaluation which evaluates progress toward achieving TMDL pollutant load reductions. The
permit specifies the required elements of the Evaluation report, including the methodology
used to evaluate progress, comparison of loadings with and without BMP implementation,
estimated effectiveness of BMPs, and a water quality trend analysis. Finally, if the permittee is
not achieving the WLA, a TMDL Pollutant Load Reduction Benchmark must be developed with
the permit renewal application.
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4.2 Monitoring & Modeling Requirements
A number of permits require their MS4s, which are identified and assigned
allocations in TMDLs, to monitor2 for the associated pollutant(s) of concern or, in
others, to model the effects of stormwater controls on the discharge of
pollutant(s) of concern. Some of these requirements are specific to the pollutant
parameter, while others require the permittee to establish a monitoring program of its
own to determine progress towards meeting applicable WLAs.
General Permits
California
The 2013 California general permit for discharges from small MS4s includes tailored
requirements for monitoring in certain watersheds. The permit specifies which permittees are
affected by the tailored requirements, and the receiving streams where the monitoring must be
performed. In some watersheds, the monitoring is intended to establish baseline pollutant
loading information, while in a number of others, the monitoring program (which is submitted
to the state as part of a Wasteload Allocation Attainment Program) is intended show whether
the MS4's program is meeting interim targets or WLA-based limits. In a number of watersheds,
in addition to the effluent monitoring requirements, permittees are required to submit a
quantifiable numeric analysis demonstrating that the BMPs selected for implementation will
likely achieve the applicable WLA according to the schedule for implementing the TMDL, based
on modeling, published BMP pollutant removal performance estimates, best professional
judgment, and/or other available tools. See, for example, the permit requirements for the San
Lorenzo River TMDL for sediment in Appendix G. See Attachment G- Region Specific
Requirements, Regional Water Board Approved TMDLs—where urban runoff is listed as a
source.
2 Note that while many Phase I MS4 permits include monitoring requirements, these have generally not been, until
relatively recently, included for the purposes of implementing TMDLs.
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4.2 Monitoring & Modeling Requirements
Georgia
The 2012 Georgia general permit for discharges from small MS4s requires permittees with a
population of > 10,000 that discharge to an impaired water either with or without an approved
TMDL to implement a monitoring plan for all pollutants of concern. The monitoring plan, which
must be submitted to the permitting authority for review and approval, is required to specify
the sampling locations, sample type and frequency, implementation schedule, and the BMPs
that will be implemented to control and reduce the pollutants of concern. Annual reports are
required to include an assessment of the data trends for each pollutant of concern. The
assessment must initially include a characterization of baseline conditions to determine the
effectiveness of the BMPs employed and what, if any, additional adaptive BMP measures may
be necessary to return the waters to comply with state water quality standards. See Section
4.4.2.
Washington
The 2013 Western Washington small MS4 general permit requires a number of its permittees to
conduct discharge or surface water monitoring for fecal coliform and to electronically submit
the results to the state. See Appendix 2.
Connecticut
The 2016 (Effective 2017) Connecticut small MS4 general permit requires additional monitoring
for MS4s discharging to impaired waters. Outfall screening for nitrogen, phosphorus, and
bacteria is required with the permit setting specific thresholds for when a follow-up
investigation is required. Screening for other pollutants requires a turbidity sample as an
indicator. See Section 6(i).
Tennessee
The 2016 Tennessee Small MS4 permit requires analytical monitoring in impaired waters (called
"unavailable parameters" in the permit). For stream segments impaired for siltation, habitat
alteration, and/or nutrients, biological stream sampling and habitat assessment must be
performed utilizing the Semi-Quantitative Single Habitat (SQSH) Method as identified in the
division's most current version of the Quality System Standard Operating Procedure for
Macroinvertebrate Stream Survey. At least one sample per stream segment must be collected,
with all segments within the MS4 jurisdiction sampled in a five-year period. For stream
segments impaired for pathogens, bacteriological stream sampling must be performed utilizing
methods identified in the division's most current version of the Quality System Standard
Operating Procedure for Chemical and Bacteriological Sampling of Surface Water. Monitoring
must include the collection of five samples within a thirty-day period (to establish a geometric
mean), and be performed during the summer (March through November). At least one series of
five samples per stream segment must be collected, with all segments within the MS4
jurisdiction sampled in a five-year period. See Part 5.1.
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4.2 Monitoring & Modeling Requirements
Individual Permits
Atlanta, GA
Georgia's Phase I MS4 permits require MS4s to propose a monitoring and implementation plan
for each pollutant of concern. The plan must include a map showing the monitoring locations
and must specify the sample type and frequency. Each annual report shall include an
assessment of the data trends for each pollutant of concern. The assessment shall initially
include a characterization of baseline conditions to determine the effectiveness of the BMPs
employed and what, if any, additional adaptive BMP measures may be necessary to return the
waterbody to compliance with state water quality standards. See, for example, Part 3.3.7 of the
Bibb County, GA MS4 permit and Part III.E of the Atlanta, Georgia, permit.
Permits available upon request: Frances.Carpenter@dnr.state.ga.us
Nashville, TN
The 2012 Nashville, Tennessee, MS4 permit includes specific monitoring instructions for waters
impaired for siltation and/or habitat alteration, and pathogens. For example, for siltation and
habitat alteration impairments, biological stream sampling must be performed utilizing the
Semi-Quantitative Single Habitat Method (October 2006). For pathogen impairments, samples
must be performed using methods identified in the permitting authority's Quality System
Standard Operating Procedure for Chemical and Bacteriological Sampling of Surface Waters
(December 2009), and they must include the collection of 5 samples and corresponding flow
measurements, within a 30-day period and must be performed between June through
September (Summer). The permit also requires Visual Stream Surveys and Impairment
Inventories on streams impaired for siltation, habitat alteration, and pathogens immediately
upstream and downstream of each MS4 outfall to identify and prioritize MS4 stream
impairment sources. See 4.1 and 4.2. For a copy of the permit, go to the Division of Water
Resources Permits Data Viewer website and search for permit TNS068047.
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4.2 Monitoring & Modeling Requirements
Florida Phase I Permits
Florida's Phase I MS4 permits require the MS4 for waterbodies with an approved TMDL, but
without a Basin Management Action Plan (BMAP), to submit to the state for review and
approval a TMDL monitoring and assessment plan within one year. The permits specify the
minimum elements of the plan, which include:
•	Develop a table showing the annual loadings currently discharged from outfalls into
waterbodies with an adopted TMDL;
•	Rank the outfalls, based on total annual loading of the pollutant(s) of concern,
discharging into each waterbody with an adopted TMDL; and
•	Based on a review of sediment and biological monitoring results from the past, validate
the results of the loading assessment that identifies the highest priority outfalls.
Once the monitoring and assessment plan is approved, the permits require storm event
monitoring for a minimum of seven storm events at the top-ranked outfall identified in the plan
to validate the estimates of annual pollutant loadings. A final report summarizing the results
must be submitted for review and approval by the state. See, for example, Parts VIII.B.3.b and c
of the 2013 Pinellas and 2011 Miami-Dade Phase I MS4 permits. Contact state for permit.
Prince George's County, MD
The 2014 Prince George's County. Maryland. MS4 permit requires the permittee to conduct
monitoring to track progress toward meeting TMDLs, specifically chemical, physical, and
biological monitoring in the Bear Branch watershed and an assessment of the effectiveness of
stormwater controls for stream channel protection in the Black Branch watershed. The permit
includes specific protocols to be followed based on the type of monitoring. For each annual
report, the permittee must submit information on the results of the monitoring as well as
pollutant load reductions related to applicable WLAs. See Part IV.F and V.A. See also similar
requirements in Part IV.F of the 2013 Baltimore County. MD MS4 permit.
Tucson, AZ
The 2011 Tucson, Arizona, MS4 permit requires the MS4 to conduct monitoring at least two
times during the first year of the permit to evaluate the effectiveness of control measures by
comparing the phosphorus loads in stormwater with the applicable WLAs in the TMDL. The
target value for ortho-phosphorus based on the WLA in the TMDL is 0.139 lbs/day minus the
load contributed by the added ground water. See Part 6.2. Contact state for permit.
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4.3 TMDL-Related Annual Reporting Requirements
Several permits require MS4s that are subject to TMDLs to report on progress
made towards implementing required management measures related to the
TMDL. These approaches provide the permitting authority with data and other
information that can be used to determine what kind of progress is being made
towards achievement of the TMDL. The following are examples of this type of
requirement.
General Permits
Arkansas
The 2014 Arkansas general permit for discharges from small MS4s requires permittees to report
on progress in meeting the permit's milestones and reducing the pollutant of concern. See
Section 3.4.5.
California
The 2013 California general permit for discharges from small MS4s requires permittees to
report annually on the status of implementation of specific TMDL components. The report must
include: (1) A description of BMPs implemented, including types, number, and locations; (2) An
assessment of the effectiveness of implemented BMPs in progressing towards attainment of
WLAs within the TMDLs' specified timeframes; (3) All monitoring data, including a statistical
analysis of the data to assess progress towards attainment of WLAs within the TMDLs' specified
timeframes; and (4) Based on results of the effectiveness assessment and monitoring, a
description of the additional BMPs that will be implemented to attain WLAs within the TMDLs
specified timeframes. See Section E.15.d.
Georgia
The 2012 Georgia general permit for discharges from small MS4s requires MS4 permittees with
populations over 10,000 that discharge to impaired waters with or without a TMDL to include
an assessment of the data trends for each pollutant of concern in their annual reports. The
initial annual report must also include a characterization of baseline conditions to determine
the effectiveness of the BMPs employed and what, if any, additional adaptive BMP measures
may be necessary to return the waters to compliance with state water quality standards. See
Section 4.4.2.
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4.3 TMDL-Related Annual Reporting Requirements
Minnesota
The 2013 Minnesota general permit for discharges from small MS4s requires the following to be
included in the annual report: (1) a list of all BMPs being applied to achieve the applicable WLA
(including a unique identifier and geographic coordinate); (2) stage of implementation for each
BMP; (3) updated estimate of the cumulative reductions in loading achieved for each pollutant
of concern; and (4) updated narrative describing any adaptive management strategies used for
making progress to achieve applicable WLA. See Part III.E and IV.B. The state also provides
specific TMDL reporting forms and training for using the forms.
Individual Permits
Prince George's Country, MD
The 2014 Prince George's County. Maryland. MS4 permit requires the permittee to submit an
annual TMDL assessment report that includes complete descriptions of the analytical
methodology used to evaluate the effectiveness of the County's restoration plans toward
achieving implementation of EPA-approved TMDLs. The County is also required to provide:
(1) estimated net changes in pollutant load reductions from all completed water quality
improvement projects, enhanced stormwater management programs, and alternative
stormwater control initiatives; (2) a comparison of the net change in pollutant load reductions
with the established benchmarks, deadlines, and applicable stormwater WLAs; (3) itemized
costs for completed projects, programs, and initiatives to meet established pollutant reduction
benchmarks and deadlines; (4) cost estimates for completing all projects, programs, and
alternatives necessary for meeting applicable stormwater WLAs; and (5) a description of
additional watershed restoration actions that can be enforced when benchmarks, deadlines,
and applicable stormwater WLAs are not being met or when projected funding is inadequate.
See Section III.E.4.
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5 Discharges to Impaired Waters Prior to TMDL Approval
Several permits identified specific actions that must be taken to
address impaired waters prior to completion of an approved
TMDL. The following examples exhibited this approach.
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5 Discharges to Impaired Waters Prior to TMDL Approval
General Permits
Arkansas
The 2014 Arkansas general permit for discharges from small MS4s specifies required actions
that must be taken by permittees that discharge to impaired waters for nutrients, bacteria, or
other pollutants of concern prior to the completion of the TMDL. For instance, for bacteria
impairments, the permittee is required to take the following actions:
•	Within 1 year, identify potential significant sources of bacteria entering the MS4;
•	Within 2 years, develop and implement a public education program to reduce the
discharge of bacteria in municipal stormwater contributed by: (1) pets, recreation and
exhibition livestock, and zoos; and (2) on-site wastewater treatment systems;
•	Within 2 years, review results from the Illicit Discharge Detection and Elimination (IDDE)
program and modify as necessary to prioritize the detection and elimination of
discharges contributing bacteria to the MS4; and
•	Include in annual reports updates to measurable goals for bacteria reduction program
elements.
See Sections 3.4.5 and 3.4.5.2.
California
The 2013 California general permit for discharges from small MS4s requires permittees to
implement additional procedures for discharges to impaired waters:
•	For the construction site inventory, provide the location of the project with respect to
all waterbodies listed as impaired for sediment and turbidity (Section E.lO.a); and
•	For the post-construction BMP condition assessment, the permittee is required to give
higher priority for maintenance to BMPs designed to remove pollutants for which the
receiving water is impaired (Section E.12.ii.b).
In addition, permittees that discharge to waters listed as impaired where urban runoff is listed
as a source must consult with the permitting authority within one year of permit coverage to
assess whether monitoring is necessary and, if so, the appropriate monitoring plan. Section
E.13.C.
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5 Discharges to Impaired Waters Prior to TMDL Approval
Georgia
The 2012 Georgia general permit for discharges from small MS4s requires existing permittees
discharging to impaired waters to develop and submit for review and approval to the
permitting authority an Impaired Waters Plan (for MS4s with a population of < 10,000) or a
Monitoring and Implementation Plan (for MS4s with a population of > 10,000).
•	The Impaired Waters Plan, which must be submitted by a specific date, must include a
list of the impaired waters and the pollutant(s) of concern, a map showing the locations
of the impaired waters and all MS4 outfalls discharging to those waters, BMPs that will
be implemented to address each pollutant of concern, and a schedule for implementing
the BMPs.
•	The Monitoring and Implementation Plan, which also must be submitted by a specified
date, must identify where wet weather monitoring will occur, sample type, frequency,
schedule to begin monitoring, and a description of the BMPs that will be implemented
to address each pollutant of concern.
The permittee is also required to annually check whether an impaired water within its
permitted area has been added to the latest 305(b)/303(d) list. Newly listed waters must be
addressed in the plan and the SWMP must be revised accordingly. See Section 4.4.2.
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5 Discharges to Impaired Waters Prior to TMDL Approval
Massachusetts
The 2016 (Effective 2017) Massachusetts small MS4 general permit identifies in Part 2.2.2 the
requirements for discharges to impaired waters without an approved TMDL. The pollutants
specifically identified include nutrients (Total Nitrogen or Total Phosphorus), solids (TSS or
Turbidity), bacteria/pathogens (E. Coli, Enterococcus or Fecal Coliform), chloride, metals
(Cadmium, Copper, Iron, Lead or Zinc) and oil and grease. The permit lists municipalities that
discharge to waterbodies impaired due to nitrogen and phosphorus. The permit also lists
requirements for waterbodies where bacteria or pathogens, chloride, oil and grease, solids or
metals are the cause of impairment. These permittees must meet the requirements in
Appendix H.
Appendix H identifies additional, specific BMPs designed to reduce the pollutant discharges in
the impaired catchments. Specific BMPs are identified where nitrogen, phosphorus, pathogens,
chloride, or solids/oil and grease/metals are the cause of impairment. For example, for
phosphorus, Appendix H requires supplemental public education on disposal of grass clippings
and proper use of fertilizers.
New Hampshire
The 2017 New Hampshire small MS4 general permit identifies in Part 2.2.2 the MS4s that
discharge to impaired waters without an approved TMDL and requires them to meet the
applicable requirements of Appendix H. The pollutants for which these requirements apply
include nutrients (Total Nitrogen and Total Phosphorus), bacteria/pathogens (E. Coli,
Enteroccus or Fecal Coliform), chloride, solids (TSS or Turbidity), metals (Cadmium, Copper,
Iron, Lead or Zinc) and oil and grease. Appendix H identifies additional or enhanced BMPs
designed to reduce the specific impairment pollutant. For example, for nitrogen, Appendix H
requires, among other requirements, MS4 operators to establish requirements for use of slow
release fertilizers on property owned by the operator in addition to reducing and managing
fertilizer as already required in the permit. Supplemental public education on disposal of grass
clippings and proper use of fertilizers is also required.
Individual Permits
Baton Rouge, LA
The 2009 Baton Rouge, Louisiana, permit requires the MS4 to develop an Interim Pollutant
Reduction Plan for discharges of a pollutant on a 303(d) list prior to completion of a TMDL.
Specific activities and dates are specified when the pollutant is a nutrient constituent, bacteria,
or another pollutant (for example, identify potential sources of nutrient pollutant within 1 year,
develop a public education program for residential/commercial uses of fertilizers within
2 years, develop a program to reduce discharge of nutrients from municipal facilities within
2 years, etc.). See Part II.B.l. Contact state for permit.
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