DEP Imposes TMDLs on the Norwalk River

What is a TMDL and what does it mean for the river, the watershed, and area residents?

The letters in TMDL stand for Total Maximum Daily Load. EPA defines a TMDL as "a calculation of the maximum amount of a single pollutant - from all contributing point and nonpoint sources - that a waterbody can receive and still meet water quality standards [without adverse impact to fish, wildlife, recreation, or other public uses]...." That calculation must include a margin of safety and account for seasonal variations in water quality.

The Clean Water Act of 1972, section 303, established the water quality standards and TMDL programs. The Act, which has had subsequent revisions, also required the states to identify the waters not meeting the standards [303(d) list], to set priorities for TMDL development, to develop a TMDL for each pollutant for each listed waterbody, to detail a Water Quality Management Plan with quantitative goals for implementing the load allocations and for reducing the pollutants using a variety of regulatory and nonregulatory approaches, and to provide the public with the opportunity to comment on the plan.

The State of Connecticut identified the Norwalk River as a Class B river, i.e., fishable and swimmable, and stocks the river as part of its recreational programs. The Norwalk could not be classified as a Class A river (drinking water potential), even though the Kellogg/ Deering wellfields off the river help supply Norwalk First Taxing District's water supplies, because the river is impaired.

The 1996 Streamwalk had identified 132 impaired sites, and DEP listed the Norwalk River as failing to meet its designated uses for 1) contact recreation (because of fecal coliform bacteria), 2) aquatic life support (perhaps from high temperatures or toxic ammonia levels), and 3) migratory fish passage (because of dams). A more complete list of cited impairments that degrade water quality include bacteria, high water temperature, decreased dissolved oxygen, increased algal growth, restricted flows, extra high and low flows, loss of riparian habitat, altered streambanks, channelization in developed areas, historic industrial spills, contaminated sediments, hydrocarbons, metals, and dams.

Pollution comes from both point and nonpoint sources. Point sources would include malfunctioning sewage treatment plants and other distinct sources. [The river accepts treated effluent from four sewage treatment plants: upstream at two in Ridgefield and one in Georgetown, and one at the harbor in Norwalk.] Nonpoint sources typically come from malfunctioning septic systems, urban runoff, and both permitted stormwater discharge and runoff from fertilizers, herbicides, pesticides, and manure from wildlife (waterfowl, horses, and pets). Indentification of problem areas and education of the public to improve them will make a difference to nonpoint pollution.

Besides education, how is NRWA trying to help improve the water quality? Early in 2001, NRWA and representatives from Harbor Watch/River Watch and the NRW Initiative went to Hartford and met with representatives from DEP and EPA to request that TMDLs be imposed on the entire river to encourage all factions to improve water quality. Years of testing by Harbor Watch/RiverWatch had documented little improvement. Clearly new incentives were needed to force action. Four months later DEP did impose TMDLs on the entire river and in March 2002 identified the testing sites to benchmark problem areas and improvements.

Meanwhile, NRWA is working to have Ridgefield extend by two months the operation time of its ultraviolet lights, which dramatically reduce coliform counts at the two Ridgefield plants, to encompass April through October, the most likely times for river contact through swimming and fishing (although fishing season continues through February). The Town of Redding has historically voluntarily engaged its UV lights all year long*.

NRWA is also funding additional water tests by Harbor Watch/River Watch at other polluted areas to pinpoint problem sources and to quantify ammonia and nitrogen/phosphorous levels that seriously threaten aquatic life. This information is useful for establishing TMDLs and upgrading sewer permits.

TMDLs are a great incentive to identify pollution sources and the improvements needed to effect better water quality. Under a TMDL additional technical help becomes available, as well as certain loans and grants. Those Mayors or First Selectmen who sign onto the program for their towns - all of which have in the past supported the Norwalk River Watershed Action Plan and its important goals - can expect government support for the improvements they would like to make for the safety of their constituents now and in the future.

*Note: The Town of Redding would put on its lights if it could, but it has been having problem with its UV lights, so they aren't working properly.

For additional information check: http://www.epa.gov/owow/tmdl/states/ctfact.html ; Clean Water Network: www.cwn.org: Status Reports March 2000 The Clean Water Act: An Owner's Manual, pp. 81-89; The River Network: www.rivernetwork.org