§ 190-215 § 190-215
solids (TSS), floatables, greases, and oils after the site is
developed. This standard is met when:
(a) The Planning Board determines’ that _ suitable
nonstructural practices for source control and pollution
prevention are implemented;
(b) Stormwater management best management practices
(BMPs) capture the prescribed runoff volume; and
(c) Stormwater management BMPs are maintained as
designed.
§ 190-215 § 190-215
D.
(1) Stormwater management systems must be designed so that
the ten-year, twenty-four-hour postdevelopment peak
discharge rate does not exceed the ten-year, twenty-four-hour
predevelopment peak discharge rates.
§ 190-214 § 190-215
ARTICLE XXXI
Stormwater Management
Purpose: The purpose of this article is to protect, maintain and
enhance public health, safety, and general welfare by establishing
minimum requirements and procedures to control the adverse
impacts associated with stormwater runoff, and soil erosion and
sedimentation from site construction and development. Subdivision
and site plans shall include plans for managing stormwater and
controlling erosion and sedimentation as provided herein.
19
Appendix A
Nashua Revised Ordinances
Artic le XXXI-— Stormwater Management
Hic it Discharge Detection and Himination Plan 19
9 Progress Re porting
The progress and success of the IDDE program will be evaluated on an annual basis. The evaluation will
be documented in the annual report and will include the following indicators of program progress:
e Number of illicit discharges identified and removed
e Number and percent of total outfall catchments served by the MS4 evaluated using the
catchment investigation procedure
e Number of dry weather outfall inspections /screenings
e Number of wet weather outfall inspections/sampling events
7 Catchment Investigations
Once stormwater outfalls with evidence of illicit discharges have been identified, various methods can be
used to trace the source of the potential discharge within the outfall catchment area. Catchment
investigation techniques include but are not limited to review of maps, historic plans, and records;
manhole observation; dry and wet weather sampling; video inspection; smoke testing; and dye testing.
6.1.3 Sample Collection and Analysis
If flow is present during a dry weather outfall inspection, a sample will be collected and analyzed for the
required permit parameters’. The general procedure for collection of outfall samples is as follows:
1. Fill out all sample information on sample bottles and field sheets
Put on protective gloves (nitrile /latex/other) before sampling
3. Collect sample with dipper or directly in sample containers. If possible, collect water from the
flow directly in the sample bottle. Be careful not to disturb sediments.
6.1.2
Field Equipment
Table 6-1. Field Equipment —- Dry Weather Outfall Screening and Sampling
Equipment
Use/Notes
Clipboard
For organization of field sheets and writing surface
Field Sheets
Field sheets for both dry weather inspection and Dry weather sampling
should be available with extras
Chain of Custody Forms
To ensure proper handling of all samples
Pens/Pencils/Permanent Markers
For proper labeling
Nitrile Gloves
To protect the sampler as well as the sample from contamination
6 Dry Weather Outfall Screening and Sampling
Dry weather flow is a common indicator of potential dlicit connections. The MS4 Permit requires all
outfalls (excluding Problem and Excluded Outfalls) to be inspected for the presence of dry weather
flow. The Engineering Department is responsible for conducting dry weather outfall screening, starting
with High Priority outfalls, followed by Low Priority outfalls, based on the initial priority rankings
described in the previous section by the end of Year 3.
