Biological Integrity in Connecticut Rivers 1989 - 2019
Clean Water Act implementation progress and needs for continuing success
Biological Assessments in CT
Significant progress has been made to clean up rivers since the passage of the federal water pollution control act (commonly known as the clean water act) in 1972. However, much of the focus has been on fixing waste-receiving streams with overt pollution problems which has left high quality streams vulnerable and open to degradation. In addition, over the past decade there have been significant cuts to funding and staff for pollution control and science at both the State and Federal levels (Environmental Integrity Project, 2019) with further cuts proposed (U.S. Office of Management and Budget, 2020) threatening continued success of clean water implementation. This map will seek to demonstrate progress made to date, while at the same time highlighting the need to modernize assessment methods to protect high quality streams from degradation and continue to augment the success of the clean water act.
The map focuses on long-term sampling sites in Connecticut non-tidal rivers and streams. Long-term sites are divided into two groups: historically polluted streams and historic sentinel streams. Historically polluted streams are those that have been significantly altered due to anthropogenic input and typically a primary focus for restoration as part of the Clean Water Act. Historic sentinel streams are those that have been least disturbed by anthropogenic input.
The presence, condition, numbers and types of fish, insects, algae, plants, and other organisms provide direct, accurate information about the health of water bodies. Biological assessments measure these factors and are the primary tool used to evaluate the condition of water bodies. Because biological communities are affected by all of the stressors to which they are exposed over time, bioassessments provide information on disturbances not always revealed by water chemistry or other measurements.
The map explores changes in biological condition measured using benthic macroinvertebrate community metrics. These organisms are very well studied and have a long history of use as indicators of water quality. The data was collected by the Water Monitoring and Assessment program at the Connecticut Department of Energy and Environmental Protection.
1989 - 1995
Macroinvertebrates as Water Quality Indicators
Macroinvertebrate community metrics include the relative abundance of sensitive, moderate and tolerant in a sample collected within the 5 year period. Tolerant species are those that can live in highly polluted waters, moderate species can endure a moderate level of pollution, while sensitive species only occur in waters with little to no pollution.
Benthic macroinvertebrates are animals without backbones, who inhabit the bottom of rivers and streams, as well as many other waterbody types. These organisms are very well studied and have a long history of use as indicators of water quality. Certain types, including mayflies, stoneflies, and caddisflies, can survive only in the cleanest water quality conditions. Other major groups of macroinvertebrates are true flies, beetles, worms, crustaceans, and dragonflies.
