WATER QUALITY OF THE NIANTIC RIVER AND ITS TRIBUTARIES
The primary sources of information used to determine the existing or known
water quality issues of the Niantic River are the CTDEP/BWM and the CT Department
of Agriculture’s Bureau of Aquaculture (DA/BA). CTDEP/BWM is charged
with regularly assessing the water quality of the State’s waters, identifying
threats, and developing remedial action. The DA/BA is responsible for implementing
the National Shellfish Sanitation Program (NSSP). These two agencies produce
regular assessments of the Niantic River that are readily available to the
public.
The CTDEP performs assessments of the State’s waters on a regular basis according to a standard methodology referred to as the, Connecticut Consolidated Assessment and Listing Methodology (CALM). CALM describes the State’s scientific approach to assessing Connecticut’s waters for determining if they support their designated uses by comparing biological, chemical and physical data to the State’s Water Quality Standards. These assessments result in biannual “Water Quality Reports to Congress” or “305b Reports.” Waters found not to support their uses are listed in a separate document referred to as, Connecticut Waterbodies Not Meeting Water Quality Standards (Impaired Waters List or 303(d) List). Once placed on the 303d List, CTDEP is required to develop a water quality restoration plan (i.e. total maximum daily load (TMDL) prescription) for it.
The Niantic River is classified as a Class SB/SA watercourse according to
the CTDEP. This classification means saline (salt) waters (S) with a current
surface water quality classification of B and a water quality goal of A.
Designated uses of Class SB waters are for fish, shellfish, and wildlife
habitat, certain aquaculture operations, recreational uses, industrial, and
other legitimate uses including navigation, but the C classification means
that the water is presently not meeting all Water Quality Criteria due to
pollution. Class SB designated uses include SC uses plus shellfish harvesting
for transfer to a depuration plant or relay (transplant) to approved areas
for purification prior to human consumption.
The freshwater tributaries of the Niantic River are designated as Class A and AA. Class A waters, which represent the greater proportion of the streams in the watershed, have designated uses as potential water supplies; they are supportive of fish and wildlife habitat; recreational uses; and adequate for use as agricultural/industrial supplies. Class AA waters, which are limited to the reservoirs and their tributaries of the northern watershed in Salem and Waterford, have designated uses as ‘existing or potential’ water supplies. In fact, the Class AA waters of the Niantic Watershed are a part of the City of New London’s public water supply system, which also serves populations of (East Lyme) Montville and Waterford.
Existing Water Quality Issues
The entire Niantic River from the railroad bridge to Golden Spur is listed on the State’s 303d List of Impaired Waters. It is listed because biological, chemical and physical data reveal that the river does not support several of its designated uses. The suspected causes and potential sources of these impairments, as well as other descriptive information are summarized in Table 4.0 below. No TMDLs have been drafted for the Niantic River (see footnote for more information).
Niantic River Segments listed on the 2004 Connecticut Waterbodies Not Meeting Water Quality Standards (303d List)
| Waterbody Segment ID | Waterbody Segment Name | Waterbody Segment Size | Waterbody Location Description | Impaired Designated Use | Use Support Category | Cause (Potential Cause) | Tier | TMDL Priority | Potential Source |
| CT2204-E_02 | Niantic Bay – upper bay and river_02 | 0.29 | Niantic River, Gold Spur Area | Aquatic Life Support | Partial | Unknown | 3 | M | Marinas, Onsite wastewater systems (septic tanks), urban runoff/storm sewers, waterfowl |
| Primary Contact – Recreation | Partial | Indicator Bacteria | 2 | L | |||||
| Shellfishing | N | Indicator Bacteria | 2 | L | |||||
| CT2204-E_03 | Niantic Bay and offshore_03 | 3.96 | Niantic River, Niantic Bay and offshore, excluding 0.2 sq. mi. near shore between Pond Point north to RR tracks, Niantic. | Aquatic Life Support | Partial | Unknown | 3 | M | Marinas, septic tanks, urban runoff/storm sewers, unknown sources, waterfowl |
| Shellfishing | N | Indicator Bacteria | 2 | L |