Search

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

| Page

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

A regular meeting of the Board of Aldermen was held Tuesday, September 12, 2017, at 7:30 p.m. in the
Aldermanic Chamber.

President Brian S. McCarthy presided; City Clerk Patricia Piecuch recorded.
Prayer was offered by City Clerk Patricia Piecuch; Alderman David W. Deane led in the Pledge to the Flag.

The roll call was taken with 14 members of the Board of Aldermen present; Alderman-at-Large Daniel T. Moriarty
was recorded absent.

Mayor James W. Donchess and Corporation Counsel Steven A. Bolton were also in attendance.

REMARKS BY THE MAYOR

Mayor Donchess

First I’d like to welcome all of our guests to the Aldermanic Chamber. In a number of years in city government,
| can’t say that I’ve ever seen or certainly a bigger crowd that we have tonight. | wanted to mention that we
have a lot going on downtown. Just this past weekend, Positive Street Art put on their arts festival in French
Park and Renaissance Park. We had the dinner on Main Street put on by Great American Downtown. Both
were extremely well attended. Both had a lot of energy, and a lot of people, and a lot of enthusiasm.

We also have a lot of residential conversions going on. We have the Franklin Street conversion with Brady
Sullivan converting the former Nashua Corp. to 200 units of housing. Just today Brady Sullivan bought the
next building on that row — 44 Franklin Street which has been owned by a group of local people for and with
that acquired an additional 100 units of parking.

More recently, we’ve had a little bit further in time we had Clocktower, way 25 years ago and Cotton Mill
Square. With this acquisition today with the acquisition by Clocktower of the Picker Building, we’re seeing an
increasing pace of residential development in downtown. Alphagraphics is building 3 new units above their
store for the first time the re-establishment of residences above some of the retail. We have music festivals.
We have the Farmer’s Market. We have the dance party. Back in July, the Latino Festival. We've seen a lot
of new people and businesses come to downtown to join those who have been here for so long. Martha’s did
a big conversion in the Merchant’s Exchange building — a big renovation many years ago. Since then, we’ve
seen a number of changes — MTs and Surf. More recently, Riverwalk, Riverside Barbecue, the Flight Center,
JaJaBelle’s, and Camaraderie have joined all of the long-standing businesses that we’ve had. | believe that if
you spend time downtown, you can feel new enthusiasm, new energy, and you can feel that the pace of
change. A positive change is accelerating and gaining momentum.

Now we have before us the performing arts center to replace the former anchor Alec’s Shoes. | believe and |
think many of the people here agree that the conversion of Alec’s to a city community performing arts center
will dramatically reinforce the positive changes that we know are occurring. Now the purpose of the performing
arts center, underlying purpose, is of course to provide entertainment but more important than that to build a
stronger, healthier economy downtown and citywide. We want to add to our tax base, increase our ability to
raise taxes for the benefit of all services. We want to develop a downtown and a community that can compete
for entrepreneurs, for young talent, for new families, and new residents so that for everyone — for native
Nashuans and for new residents alike Nashua is city that people love to live in.

Now the performing arts center will bring 50 to 75,000 new people downtown. Two or three performances a
week with 400 or 500 people or more attending. It will be run as a business. It will be commercially viable.
Now as you’ve read in the newspaper in the last few days, we have a potential partner with the Currier
Museum from Manchester. Probably the State’s leading artistic institution. This will bring $1 million that
formally we were afraid would go back to Manchester back to Nashua and the Currier is joining us and is
enthusiastic about this partnership. The Currier believes that the performing arts center on Main Street is a
fantastic project. They want to be part of that. When has that happened in Nashua before?

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

4 Sanitary Sewer Overfiows (SSOs)

The City of Nashua is authorized to discharge from the Nashua Wastewater Treatment Facility and nine
combined sewer overflows (CSOs) to the receiving waters of Merrimack River (Wastewater Treatment
Facility (Outfall 001) and CSOs (Outfalls 002-005 and 014)) and Nashua River (CSOs (Outfalls 006-009)
under the Nashua Wastewater Treatment Facility NPDES Permit No. NH0100170. Under Section E.6
(g) of NPDES Permit No. NH0100170, SSOs are tracked and reported, pursuant to NH MS4 General
Permit Section 2.3.4.4(d). A summary of the SSOs and their causes, and a report of any corrective
actions taken as a result, are reported in the annual report related to the implementation of the
Collection System O&M Plan, submitted to EPA and New Hampshire Department of Environmental
Services (NHDES) under NPDES Permit No. NH0100170.

Hic it Discharge Detection and Himination Plan 8

5 Assessmentand Priority Ranking of Outfalls

The MS4 Permit requires an assessment and priority ranking of outfalls in terms of their potential to
have ilicit discharges related public health significance. The ranking helps determine the priority order
for performing IDDE investigations and meeting permit milestones.

5.1 Outfall Catchment Delineations

The catchments for each of the MS4 outfalls will be delineated to define contributing areas for
investigation of potential sources of illicit discharges. Refined catchment delineations will be completed
as part of the Phase II mapping to reflect information collected during catchment investigations

5.2 Outfall nventory and Initial
Ranking

Nashua has completed an initial outfall and interconnection inventory and priority ranking to assess
illicit discharge potential based on existing information. The inventory will be updated annually to
include data collected in connection with dry weather screening and other relevant inspections and
included in each annual report.

Outfalls were classified into one of the following categories:

1. Excluded outfalls:
¢ Outfalls with no potential for illicit discharges including roadway drainage in undeveloped
areas with no dwellings and no sanitary sewers; drainage for athletic fields, parks or
undeveloped green space and associated parking without services; cross-country drainage
alignments (that neither cross nor are in proximity to sanitary sewer alignments) through
undeveloped land.

2. Problem Outfalls: Outfalls with known or suspected contributions of illicit discharges based
on existing information shall be designated as Problem Outtfalls. This shall include any outfalls
where previous screening indicates likely sewer input. Problem Outfalls need not be screened
pursuant to Dry Weather Outfall and Interconnection Screening and Sampling. Likely sewer
input indicators are any of the following:

e Olfactory or visual evidence of sewage,

e Ammonia 2 0.5 mg/L, surfactants 2 0.25 mg/L, and bacteria levels greater than the
water quality criteria applicable to the receiving water, or

e Ammonia 2 0.5 mg/L, surfactants 2 0.25 mg/L, and detectable levels of chlorine.

3. High Priority Outfalls: Outfalls that have not been classified as Problem Outfalls and that are:

e Discharging to an area of concern to public health due to proximity of public beaches,
recreational areas, drinking water supplies or shellfish beds

Hic it Discharge Detection and Eimination Plan