Water Quality - Current Conditions

In Rhode Island, the RI DEM 2008 Integrated Report (RIDEM 2008) provides the most up to date assessments of water quality. Approximately half (740 miles of the state’s 1,498 miles) of freshwater rivers have been assessed for water quality. Of these, only 0.03 % (0.21 miles) are fully supporting all their designated uses. This low percentage is in part due to the lack of fish tissue data which prevents the comprehensive assessment of all designated uses. Approximately 45 % (334 miles) of the river miles assessed are impaired for one or more designated uses and 35 % (261 miles) of the river miles assessed have an impairment requiring development of a water quality restoration plan, or TMDL.Fig. FW1. Supported designated use in Rhode Island rivers and streams.

* 52 rivers, representing 113 river miles, are located within Drinking Water Supply systems and are almost entirely un-assessed. This is because the RI Health Department only requires monitoring in accordance with the Safe Drinking Water Act of the terminal reservoir of a water supply system.

Fig. FW.2.: Assessment of designated uses in Rhode Island’s lakes and ponds (RIDEM, 2008)Pathogen contamination of rivers is an ongoing problem with implications as rivers are used more for recreation (paddling on the Blueway system, Water Fire, etc). The suspected sources are point and nonpoint sources such as combined sewer overflows (CSOs), seepage from failing septic systems, runoff during storm events and natural sources such as wildlife and water fowl. As of June 2008, all approved water quality restoration (TMDL) plans on Rhode Island rivers include fecal coliform in the impairments addressed by the study: Pettaquamscutt River including Mumford Brook and Gilbert Stuart Stream (RI DEM 2001), Sakonnet River (RI DEM 2005) , Saugatucket River (RI DEM 2003), Barrington River (RI DEM 2002), Hunt River including Fry Brook and Scrabbletown Brook (RI DEM 2001), Kickemuit River (RI DEM 2006), Palmer River (RI DEM 2002), Runnins River (RI DEM 2002), Woonasquatucket River (RI DEM 2007), Factory Pond Stream and Teal Pond Stream (RI DEM 2006).

Biodiversity impacts are another significant cause of non-support for rivers and streams. The greatest affect on the biological community on wadeable streams around the state appears to be generally due to nonpoint sources of pollution such as runoff. The biological community impairments on the deeper rivers appear to be due to both point and nonpoint sources of pollution such as stormwater runoff and CSOs.

Fig. FW.3: RIDEM Designated Use Assessment in Rhode Island’s rivers and streams.The aquatic life criteria for metals are often exceeded in rivers. The sources are complex and vary from permitted industrial and municipal discharges to CSOs and storm drains. Contaminated sediments and nonpoint sources such as urban runoff also contribute metals to the state’s rivers and streams.

In 2008 approximately 16,345 acres (78 %) of the 20,917 lake acres in Rhode Island were assessed for water quality. Only 0.67% (109.36 acres) of the lake acres assessed are fully supporting all their designated uses. This low percentage is in part due to the lack of fish tissue data that prevents the comprehensive assessment of all designated uses. Approximately 53% (8,741 acres) of the lake acres assessed are impaired for one or more of their designated uses and 10 % (1,608 acres) of the lake acres assessed have an impairment requiring development of a water quality restoration plan (TMDL).

Fig. FW3.: RIDEM (2008) designated use support in Rhode Island’s lakes and ponds

Fig. FW4.: Assessment of designated uses in Rhode Island’s lakes and pondThe largest cause of impairment (by acreage) to lakes and ponds in Rhode Island is the presence of exotic or invasive species (RIDEM 2008). RIDEM conducted a field survey during 2007 to identify if aquatic invasive plants were present at lake access points and at other monitoring sites in rivers. URI Watershed Watch and the Rhode Island Natural History Survey trained volunteers to conduct aquatic invasive plant surveys. These studies show a potentially widespread problem.

High bacteria and nutrient levels and low dissolved oxygen are major causes of non-support for RI’s lakes and ponds. Nonpoint sources such as stormwater runoff from urban areas and agricultural lands, internal nutrient recycling and leachate from septic systems are some of the suspected sources of pollution to the state’s lakes and ponds. Elevated levels of mercury in fish found in 19 lakes is also a major cause of non-support. RIDEM recently finalized, and EPA approved, a regional mercury TMDL for this impairment and identified atmospheric deposition as the source.

As of June, 2008, all draft and approved water quality restoration studies (TMDL) of freshwater lakes and ponds in Rhode Island address elevated phosphorus concentrations: Sands Pond (RI DEM 2008); Almy Pond, Brickyard Pond, Gorton Pond, North Easton Pond, Roger Williams Park Ponds, Sand Pond, Spectacle Pond, Upper Dam Pond and Warwick Pond (RI DEM 2007); Yawgoo Pond (RI DEM 2004); Stafford Pond (RI DEM 1998); and Mashapaug Pond (RI DEM 2007).

Fig. FW.5.: Percent of watershed river miles in Massachusetts in 305(b) assessment categories (2006)The Massachusetts 2006 Integrated List of Waters report provides an assessment of water quality in the Blackstone, Taunton and Ten Mile Rivers as well as the Mt. Hope Bay and Narragansett Bay watershed. Massachusetts does not list any of their waters as fully supporting their designated uses because there is a statewide health advisory for fish consumption.

Water quality is impaired with a TMDL required in over half the 422 miles of river in the Massachusetts portion of the Narragansett Bay watershed. About 19 % of the waters are not assessed, 3% demonstrate an impairment that is not causedby a pollutant, 3 % have a completed TMDL and 22 % attain some uses.

Fig. FW.6.: Percent of watershed lake acres in Massachusetts in 305(b) assessment categories (2006)

In the 21,613 acres of Massachusetts lakes and ponds in the Narragansett Bay watershed (Division of Water Management (2007), 25 % require a TMDL, 28 % have an impairment that is not caused by a pollutant, 38 % of the lake acres are not assessed, 6 % meet some of their designated uses and 1.5 % have a completed TMDL. 

 

Water Quality - Trends

Investments in waste water treatment result in improved water quality:  Six of Rhode Island’s nineteen major wastewater treatment facilities (WWTF) discharge directly into rivers and five WWTFs in Massachusetts discharge to rivers in the Narragansett Bay Watershed (Ten Mile and Blackstone). Since the passage of the Clean Water Act in 1972, significant investment in waste water treatment has resulted in improved water quality in rivers throughout the watershed.

The Pawtuxet River is a particular success story. Three municipal wastewater treatment facilities (West Warwick, Warwick and Cranston) discharge directly to the Pawtuxet River. Field studies in 1980 showed that these discharges caused oxygen problems in the lower river. In May 1989, RIDEM re-issued permits to all three facilities which required the communities to construct advanced treatment facilities to reduce the discharge of organic materials and ammonia and to evaluate alternatives to reduce the discharge of metals. Construction of advanced treatment upgrades has now been completed at all three facilities and the plants are in compliance with their permit limits. In-stream monitoring of dissolved oxygen concentrations during the late summer of 2007 documented improved conditions and compliance with the dissolved oxygen water quality standard. The Pawtuxet River main stem was removed from the Rhode Island list of impaired waters in 2008 due to these water quality improvements.

Improvements in the Blackstone (Blackstone River Coalition, 2008) and Taunton River (Taunton Wild & Scenic River Study Commission, 2005) can also be attributed to wastewater treatment plant upgrades. The Blackstone River has also been removed from the Rhode Island list of impaired waters for unionized ammonia, likely due to wastewater treatment plant upgrades.

Section Index      Next Section