LEARNING & EXPLORING

ORV Detail - Water Quality

Additional Water Quality Documents

Water Quality Report - PDF from Management Plan Appendices.

The following text is an excerpt from the Watershed Management Plan Chapter VI.

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1. The Importance of Water Quality

Healthy river systems can support a myriad of sustainable uses. They provide habitat for unique plants and animals, can serve as a drinking water supply, and offer recreational opportunities such as swimming, boating or fishing. The long term sustainability of such river resources is strongly tied to the quality of the water flow they rely on.

Two key factors were considered when assessing water quality conditions in the Eightmile River Watershed: (1) the status of key chemical and biological indicators; and (2) the level of current threats to water resources.

An important indicator of chemical and biological water quality is provided by the community of bottom dwelling aquatic organisms known as benthic macroinvertebrates. Because some of these organisms are highly sensitive to water pollution and habitat change, the composition of species found living in a river or stream reflects long-term water quality. Benthic macroinvertebrate surveys in the Eightmile indicate that ecological conditions are exemplary in the main stem and very good in the East Branch. The data demonstrate that water quality and aquatic habitat in the Eightmile is not only locally exemplary, but as good as the best rivers studied in the state.

In addition to having outstanding water quality, major threats to water resources that are typically seen in other watersheds are almost nonexistent in the Eightmile. The two primary threats to water quality are point source and nonpoint source pollution. Currently, there are no point source discharges in the Eightmile watershed. Point sources are generally associated with discharge pipes from industrial uses such as wastewater treatment plants or factories. Nonpoint source pollution (NPS), on the other hand, can come from any type of land use, including residential, agricultural, industrial and commercial properties. The most common types of NPS pollution are sediments, fertilizers, pesticides, oils and greases. Once contaminants accumulate on impervious surfaces (e.g., roads, parking lots, and roofs), residential lawns and agricultural fields they are carried by stormwater runoff into wetlands, rivers, streams, lakes, and ponds.

One measure of NPS impairment is the amount of impervious cover. Past scientific research has suggested that in watersheds of up to 10 square miles stream quality and aquatic health can degrade when impervious cover reaches 10% of the total watershed area. Recent research is showing that impervious cover levels as low as 4-5% can have significant affects on aquatic health. A study of over 1,000 streams in Maryland found that brook trout were never found in streams that had contributing watersheds with impervious cover over 4%.

Other key features that indicate high water quality include intact riparian corridor lands and a natural hydrologic system. Riparian corridors are upland areas directly adjacent to streams or rivers that have a biological, hydrological and physical connection to the nearby watercourse. The riparian corridor has many important ecosystem functions, including filtering sediment and other pollutants from stormwater runoff and storing flood waters during seasonal flooding events. Riparian vegetation also stabilizes stream and river banks and provides shade that helps keep water temperatures low and dissolved oxygen levels high. A natural hydrologic system includes maintaining normal stream and river flows. Stream flow affects a number of variables associated with water quality including: water temperature; dissolved oxygen; effluent dilution; effluent assimilation; sediment transport and salinity intrusion.

Recognizing these many factors, water quality in the Eightmile River Watershed can be described as follows:

92% of all of the Eightmile’s rivers and streams and 99% of all the watershed’s ground water meets the State of Connecticut Class A water quality classifications or better.
Due to the chemical, physical and biological conditions of the water, all waterbodies in the watershed evaluated by the state fully meet their water quality use goals.
None of the water bodies in the watershed are impaired from meeting their water quality use goals.
Studies of the aquatic insects (benthic macroinvertebrates) within the watershed found conditions that represent the best attainable results when compared to any of the state’s reference stream sites.
There are no wastewater or industrial surface point source discharges in the watershed.
Impervious cover in 58% of Eightmile River Watershed’s sub-watersheds is under 3%, with 99.7% of the sub-watersheds having less than 7% impervious cover.
Riparian corridors are essentially intact and continuous, with only 6% of the riparian land considered developed, and 25% permanently protected, within 100 feet of rivers and streams in the watershed.
A natural hydrology and flow regime exists.
80% of the watershed is forested with less than 7% developed
There are no subsurface discharges impairing water quality.

This substantial amount of information represents data that provides direct indication of high water quality, as well as data that underscores the pristine condition in which this river system exists, remaining relatively free from water quality threats. As such it is clear the water quality of the Eightmile River Watershed is exemplary in the State of Connecticut and an outstanding resource value for the watershed ecosystem.

A complete report on water quality can be found in Appendix 1 – Outstanding Resource Value – Water Quality.

[See Map 17: Water Quality]

2. How Water Quality is Threatened

Surface and ground water quality can be impacted in many ways. Land use near a river has a significant impact on water quality. Forest land, farm land, residential land and industrialized land, all have the potential to impact local water quality in different ways through generating point and nonpoint pollution sources. The physical condition of the stream and whether it is dammed, diverted, or piped underground can play a key role in long-term water quality. And, pollutants such as mercury or nitrogen can be carried through the air, over the land, or through the soil ultimately being deposited in local water ways.

An assessment of water quality threats in the Eightmile River Watershed identified 19 potential activities that could cause water conditions to degrade. The greatest threats identified come from the possible impacts of new development including: increases in impervious cover causing increased polluted stormwater runoff; installation of poor stormwater management systems; destruction of riparian vegetation that buffers river and stream edges; and new suburban lawns creating polluted runoff from fertilizer and pesticide applications. In addition, the altering or filling of streams and wetlands, especially in headwater areas was also identified as a significant threat.

3. Existing Protections and Gaps

In order to understand potential additional protection needs for water quality a comprehensive review was completed of current protection measures planned and implemented at the local, state and federal level.

Some of the key existing protections for water quality at the local, state and federal level include:

Regulations for managing activities occurring in wetlands and watercourses, including local inland wetlands and watercourse regulations and the Clean Water Act Section 404 program implemented by the Army Corps of Engineers.
Requirements for erosion and sedimentation control for activities that could impact wetlands and watercourses. The Connecticut General Statutes Sections 8-2 and 8-25 authorize the zoning commission to adopt regulations that require erosion and sedimentation control plans for disturbances greater than ½ acre in size.
One community, East Haddam, uses the most current best management practices for the design and installation of new stormwater management systems by following the Connecticut Dept. of Environmental Protection Stormwater Quality Manual.
All three communities have inland wetland upland review areas that provide some oversight regarding activities within riparian corridors; however they do not directly regulate activities that affect riparian corridor functions.
Lyme has adopted setback standards in their zoning regulations that protect riparian functions in the Gateway Zone , including Hamburg Cove. The regulations call for no vegetative cutting within 50 feet of the high tide line and no structures within 100 feet.
28% of the entire watershed is permanently protected open space as well as 25% of the land within 300 feet of the rivers and streams of the watershed.

Current local, state and federal programs apply various regulatory and non-regulatory tools to address water quality threats. Some threats are being adequately addressed through existing mechanisms, while others are not being directly addressed in any meaningful way. While it is clear the local communities have implemented a number of critical tools to help protect overall watershed health, a number of potential additional tools have been identified that could further advance the protection and enhancement of water quality. These additional tools are discussed in Section VI.

Gaps in protection were identified as a result of comparing known water quality threats with existing protection measures. Primary gaps in protecting water quality were found to be associated with:

riparian corridor protection
stormwater design and management
watercourse crossing design
stormwater management associated with local and state roadways
aquifer protection – including areas not currently associated with public drinking water supply
septic system maintenance
residential underground storage tank removal
agricultural practices that are exempt from review or oversight by local commissions
public education regarding nonpoint source pollution for landowners
gravel extraction regulations in each community do not address the water quality impacts of potential graveling operations

4. Water Quality Protection Goal

The water quality goal for the Eightmile River Watershed is to understand, maintain and enhance the chemical, physical and biological quality of the surface and ground water of the Eightmile River Watershed, ensuring it always supports the needs of native wildlife, aquatic life, and traditional recreational uses.

5. Water Quality Indicators

a. Riparian Corridor condition
b. Impervious Cover
c. Point Source Pollution Discharges
d. Natural Flow Characteristics
e. Chemical, Physical & Biological Characteristics
f. Non-point Source Pollution Discharges
g. Intact Natural Processes