CT ECO Basic Data Guide

Connecticut 303(d) Impaired Waters 2008

Connecticut 303(d) Impaired Waters 2008

Description and Purpose

Connecticut 303(d) Impaired Waters 2008 is a subset of Connecticut 305(b) Assessed Waters 2008. If one of the designated uses is categorized as not Fully Supporting the assessed waterbody is considered impaired. Additional information about Integrated Water Quality reporting is available at the CT DEP website.

Connecticut 305(b) Assessed Waters 2008 includes rivers, lakes and estuaries that have been assessed in compliance with Sections 305(b) and 303(d) of the federal Clean Water Act. Section 305(b) of the Clean Water Act requires each state to monitor, assess and report on the quality of its waters relative to attainment of designated uses established by the State's water quality standards. Section 303(d) requires each State to compile a subset of that list identifying only those waters not meeting water quality standards and assign a Total Maximum Daily Load (TMDL) priority ranking to each impaired waterbody

This assessment is based on information collected and compiled prior to 2008. It represents conditions at a particular point in time and does not represent current conditions. Depending on the type of waterbody - river, lake, or estuary - this informaiton geographically displays attainment and non-attainment (e.g. full supporting, not supporting, not assessed) for each designated use - aquatic life, marine aquatic life, recreation use, fish consumption, shellfish havesting, and drinking water supply.

Using this information in the CT ECO Map Viewers

This information is available in both the CT ECO Simple Map Viewer and Advanced Map Viewer. Use the Identify Tool in the Advanced Map Viewer to select individual waterbodies and obtain attainment and non-attainment information for each designated use.

Dataset Information

  • Status - No plans to update
  • Date of Data - Based on information collected and compiled prior to 2008
  • Map Scale and Accuracy - The information meets horizontal National Map Accuracy Standards for 1:24,000-scale mapping (1 inch = 2,000 feet).

Additional Documentation


GIS Data Download

  • Connecticut 305(b) Assessed Waterbodies data is downloadable from DEEP GIS Data.
  • Connect GIS and AutoCAD software to this information online using the Water Resource Management CT ECO Map Service.