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City of Nashua, NH
MS4 Assistance 2021-2022
Scope of Work for Engineering Services

Schedule:

Task 1: Begin no later than February 28, 2021 and end prior to May 31, 2021
Task 2: Begin no later than February 28, 2021 and end prior to May 31, 2021
Task 3: Begin no later than February 28, 2021 and end prior to May 31, 2021
Task 4: Begin no later than July 1, 2021 and end prior to May 31, 2022

Task 5: Begin no later than July 1, 2021 and end prior to May 31, 2022

Task 6: Begin no later than July 1, 2021 and end prior to May 31, 2022

Task 7:
e Year 3 Annual Report — Begin June 30, 2021 and end prior to September 30, 2021
e Year 4 Annual Report — Begin June 30, 2022 and end prior to September 30, 2022

Fee: See Attachment B for detailed fee calculations
Total Fee: $ 187,550 (including screening/sampling sub-consultant)

JANUARY 2021

Attachment A

Illicit Discharge Detection and Elimination
(IDDE) Program

Nashua, New Hampshire

Prepared By:
City of Nashua &
Hazen and Sawyer

Using the Template Prepared By:
Seacoast Stormwater Coalition &
Manchester/ Nashua Stormwater Coalition

EPA NPDES Stormwater Permit Number NHR041021
EPA NPDES Wastewater Permit Number NH010070

Table of Contents

Illic it Disc harge Detection and Himimation Plan

11
1.2
1.3

21
2.2

3.1

3.2

5.1

5.2

6.1

6.2

7.1

MS4 Program .........ccsssesesscesessssssseeecceessssssssceeseeeessossceeeeeesssesessseeeseeessseesssseeeseeesseoees 3
Tilicit Discharges ...........ccccccsssssenecceesssssssssseneceesssessssseeecesssssssceeseeesssessssseeeseeeeesoeees 3
Allowable Non-Stormwater Discharges ...........cccccscccccsscesesssseneceeessssesssseeeseeessoseees 4
Legal Authority...........ccccsccsssssseneceesssssssssoeneceeesssssssnseeesssesesssceeseeeesssssssseeseeeeesooees 6
Statement of Responsibilities .................ssseeneccessesssssseeeceeeessssoeeeceeessssssssseeeeeeesoeees 6
Phase I Mapping ...........:csccsssssseceseessssssssssecceeessssssssseeessssssssseeeseeessessssseeeseeeeesooees 7
Phase IT Mapping. .........ccccsssssscsecceessssssssseeceessscsssssseeesssssssssceeeeeesssesssssseeeeeeessoseses 7
Outfall Catchment Delineations ......... ccc ccc cceseeeesseneesecesenessseneesesseeeesecseesenssseenes 9
Outfall Inventory and Initial Ranking... cece seeeecceeessessssseeeeeeeessssseeeeeeeesoeees 9
Dry Weather Screening /Sampling Procedure...............:ccscccceseeeseceeeeeeeeeeeenenenenens 13
6.1.1 General Procedure 2.0.0. ceseneseneenerererererenenenenerenenscseseseseseseseeesseeeseeeeeetes 13
6.1.2 Field Equipment oo... ccc eceseeeseeeeseeneneeneeseensscensneessncessneessneeseaes 14
6.1.3 Sample Collection and Anallysis.....0.00.0.00.0.0 ccc cere ee reneereneeneneessneeenes 15
Follow-up Ranking of Outfalls............... ce sessscessssssssseeeessesssssceeeeeeessesssssseeeeeeeseoees she)
Illicit Discharge Removall............cccccsssssssecceesssesssecceesssssessseeseeeesssssssseeeeeeeesssoeoes 16

i|Page

Table 1-1. IDDE Program Implementation Timeline... eee reseenesneeseeneeneseeneeresieensessaseneeneeneenss 5
Table 6-1. Field Equipment — Dry Weather Outfall Screening and Sampling.........ccccceeee eects 14

Figure 1-1. IDDE Investigation Procedure Framework... ccc ceceeeseeee sees eeeseenesseeseseensseessneensseessneeneenenes 5

Appendix A — Nashua Revised Ordinances Article XX XI Stormwater Management

Appendix B — List of Impaired Waters Storm System Mapping

Appendix C — Outfall Inventory and Priority Ranking Matrix

Appendix D —IDDE Employee Training Record

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1 IDDE Program Implementation Tim e line

11 MS Pogrm

This Illicit Discharge Detection and Elimination (DDE) Plan has been developed by the City of
Nashua to address the requirements of the United States Environmental Protection Agency’s (USEPA’s)
2017 National Pollutant Discharge Elimination System (NPDES) General Permit for Stormwater
Discharges from Small Municipal Separate Storm Sewer Systems (MS4) in New Hampshire, hereafter
referred to as the “2017 New Hampshire MS4 Permit” or “MS4 Permit.”

The 2017 New Hampshire MS4 Permit requires that each permittee, or regulated community, address
six Minimum Control Measures. These measures include the following:

Public Education and Outreach

Public Involvement and Participation

Illicit Discharge Detection and Elimination Program

Construction Site Stormwater Runoff Control

Stormwater Management in New Development and Redevelopment (Post Construction
Stormwater Management); and

6. Good Housekeeping and Pollution Prevention for Permittee Owned Operations.

WR WN

Under Minimum Control Measure 3, the permittee is required to implement an IDDE program to
systematically find and eliminate sources of non-stormwater discharges to 1ts municipal separate storm
sewer system and implement procedures to prevent such discharges. The IDDE program must also be
recorded in a written (hardcopy or electronic) document. This IDDE Plan has been prepared to address
this requirement.

1.2 Illicit Discharges

An “illicit discharge” 1s any discharge to a drainage system that is not composed entirely of stormwater,
with the exception of discharges pursuant to a NPDES permit (other than the NPDES permit for
discharges from the MS4) and discharges resulting from fire-fighting actrvities.

Illicit discharges may take a variety of forms. Illicit discharges may enter the drainage system through
direct or indirect connections. Direct connections may be relatively obvious, such as cross-connections
of sewer services to the storm drain system. Indirect illicit discharges may be more difficult to detect or
address, such as failing septic systems that discharge untreated sewage to a ditch within the MS4, ora
sump pump that discharges contaminated water on an intermittent basis.

Some illicit discharges are intentional, such as dumping used oil (or other pollutant) into catch basins, a
resident or contractor illegally tapping a new sewer lateral into a storm drain pipe to avoid the costs of a
sewer connection fee and service, and illegal dumping of yard wastes into surface waters.

Hic it Discharge Detection and Himination Plan 3

Some illicit discharges are related to the unsuitability of original infrastructure to the modern regulatory
environment. Examples of illicit discharges in this category include connected floor drains in old
buildings, as well as sanitary sewer overflows that enter the drainage system. Sump pumps legally
connected to the storm drain system may be used inappropriately, such as for the disposal of floor
washwater or old household products, in many cases due to a lack of understanding on the part of the
homeowner.

Elimination of some discharges may require substantial costs and efforts, such as funding and designing
a project to reconnect sanitary sewer laterals. Others, such as improving self-policing of dog waste
management, can be accomplished by outreach in conjunction with the minimal additional cost of dog
waste bins and the municipal commitment to disposal of collected materials on a regular basis.

Regardless of the intention, when not addressed, illicit discharges can contribute high levels of
pollutants, such as heavy metals, toxics, oil, grease, solvents, nutrients, and pathogens to surface waters.

1.3. Allowable Non-Stomwater
Disc harges

The following categories of non-storm water discharges are allowed under the MS4 Permit unless the
permittee, USEPA identifies any category or individual discharge of non-stormwater discharge as a
significant contributor of pollutants to the MS4:

e Water line flushing e Irrigation water, springs
e Landscape irrigation e Water from crawl space pumps
e Drverted stream flows e §=Footing drains
e Uncontaminated ground water e Lawn watering
infiltration (as defined at 40 CFR e = Individual resident car washing
35.2005(20)) e De-chlorinated swimming pool
e Uncontaminated pumped groundwater discharges
e Discharge from potable water sources © Street wash waters
e Foundation drains e Residential building wash waters
e Air conditioning condensation without detergents

If these discharges are identified as significant contributors to the MS4, they must be considered an
“llicit discharge” and addressed in the IDDE Plan (1.e., control these sources so they are no longer
significant contributors of pollutants, and/or eliminate them entirely).

Hic it Discharge Detection and Himination Plan 4

Figure 1-1. IDDE Investigation Procedure Framework

Inventory and Eryn yssarenc Follow-Up

eee a Ole arll

Rank Outfalls (e-| cea ae Screening

i an or an on ae |

System has
been fully

via A ee vialely eed ees Remove lllicits

poll d et =d ay alt Investigations

Investigated

Table 1-1. IDDE Program Implementation Timeline

Completion Date from Effective Date of Permit
IDDE Program Requirement

1 Year 1.5 Years | 2 Years 3 Years 7 Years 10 Years

Written IDDE Program Plan XxX

Initial Outfall Ranking XxX

Written Catchment Investigation
Procedure

Phase | Mapping X

Phase Il Mapping XxX

IDDE Regulatory Mechanism or By-
law (if not already in place)

Dry Weather Outfall Screening XxX

Follow-up Ranking of Outfalls

Catchment Investigations — Problem
Outfalls

Catchment Investigations — all
Problem, High and Low Priority Xx
Outfalls

Effective date of the permit is July 1, 2018

Hic it Discharge Detection and Himination Plan 5

2 Authority and Statement of IDDE Responsibilities

2.1 LIegal Authority

As part of the Nashua Revised Ordinances (NROs), the City adopted a Stormwater Management
ordinance in 1998 to address runoff from sites being developed or redeveloped. Since then, the
ordinance has been reviewed and revised to incorporate requirements of the 2003 MS4 Permit and
address other necessary language modifications. Through the City Charter and Nashua Revised
Ordinances, adequate legal authority 1s provided to:

e =Prohibit ilicit discharges

e Investigate suspected illicit discharges

e =Eliminate illicit discharges, including discharges from properties not owned by or controlled by

the MS4 that discharge into the MS4 system
e Implement appropriate enforcement procedures and actions.

A copy of NRO Article XXXT Stormwater Management is included in Appendix A. The Stormwater
Management ordinance and related land use regulations and policies will be reviewed for consistency
with the 2017 MS4 Permit.

2.2 Statement of Responsibilities

The Division of Public Works takes the lead in implementing the IDDE program. Other agencies or
departments with responsibility for aspects of the program include:

e Division of Public Works/Engineering: Responsibilities for the Engineering Department
include managing the GIS, creating and updating maps of inventory, creating the written [DDE
program, and conducting dry weather screening.

e Division of Public Works/ Wastewater: Responsibilities for the Wastewater Department include
investigation of suspect sources using dye testing and CCTV inspection, implementing
catchment, training employees on IDDE implementation, conducting dry and wet weather
outfall screening, testing of samples in their laboratory.

e = Division of Public Works/Solid Waste: Responsibilities for the Solid Waste Department are
running the Hazardous Waste Collection program.

Hic it Discharge Detection and Himination Plan 6

3 Stormwater System Mapping
A copy of the existing storm system map 1s provided in Appendix B.

The City of Nashua has managed a GIS system since 2000, which has been continuously updated to
reflect up to date stormwater system information. Nashua’s GIS Specialist within the Division of Public
Works 1s responsible for updating the stormwater system mapping pursuant to the 2017 MS4 Permit.
The City of Nashua will report on the progress towards completion of the storm system map in each
annual report. The most up-to-date map can be found at the following link:
https://newegis.nashuanh.gov/NashuaNH/default.aspx.

The MS4 Permit requires the storm system map to be updated in two phases as outlined below.

3.1 Phase IMapping

The City has completed all Phase I Mapping requirements, as listed below:

e Outfalls and receiving waters (previously required by the MS4-2003 permit)

e Open channel conveyances (swales, ditches, etc.)

e Municipally owned stormwater treatment structures

e Water bodies identified by name and indication of all use impairments as identified on the most
recent EPA approved Massachusetts Integrated List of Waters report

e Initial catchment delineations. Topographic contours and drainage system information may be
used to produce initial catchment delineations.

3.2 Phase II Mapping
The City has completed the following Phase I] Mapping requirements:

e¢ Outfall spatial location (latitude and longitude with a minimum accuracy of +/-30 feet)
e Pipes

e Manholes

© Catch basins

e Municipal Sanitary Sewer system (if available)

e Municipal combined sewer system (if applicable).

Phase II mapping must be completed within ten (10) years of the effective date of the permit July 1,
2028) and include the information per Part 2.3.4.5.b of the MS4 Permit. Still outstanding as part of the
Phase II Mapping requirements 1s the following:

e Refined catchment delineations. Catchment delineations must be updated to reflect information
collected during catchment investigations.

Hic it Discharge Detection and Himination Plan 7