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2010 Section 303(d) List Overview

The New York State CWA Section 303(d) List of Impaired Waters

The 2010 NYS Section 303(d) List of Impaired Waters Requiring a TMDL (or other strategy) was originally submitted to USEPA in March 2010. A Final List was approved by USEPA Region 2 in June.

Submission and Approval

A DRAFT 2010 Section 303(d) List was made available for public comment for a 45 day period that ended February 26, 2010. After considering comments received from the public, a revised Proposed Final List was submitted to USEPA on March 26, 2010, ahead of the April 1 mandated date for submission of the List. Additional discussion during the USEPA review of the List led to other revisions and the re-submittal of a Final 2010 List to USEPA (dated June 21, 2010). This version of the List was found by USEPA to meet the requirements of Section 303(d) of the Clean Water Act and was approved on June 29, 2010.

Changes from Previous (2008) List

The 2010 NYS Section 303(d) List contains a total of 828 waterbody/pollutant listings; a small (5%) increase from the 787 listings in the 2008 List. The total number of individual waterbodies listed also increased by 5%, from 562 to 588 (some waters are impaired by multiple pollutants; hence the larger number of waterbody/pollutant listings.) This increase is largely the result of previously unassessed waterbodies that are not necessarily newly impaired, but have only been recently identified as such. This observation is not intended to minimize the importance of these new listings, but to point out that the additions do not necessarily reflect a declining trend in statewide water quality, but rather reflect an increase in the coverage of the monitoring and assessment effort. For additional perspective, note that over the same two year period the number of waterbodies assessed as having no known impacts increased by 44%, from 680 to 977. The actual change in the list is greater than reflected in the net change of 41. A total of 63 waterbody/pollutants listings were removed from the List, while 104 were added. Eighteen (18) other listings were moved from one part of the list to another, and two other listings were replaced with more appropriate listings.

The justifications for the 63 waterbodies removed from the list vary and include:

  • completion of a TMDL to address an impairment (22 of the delistings),
    • 15 due to 2007 NE Regional Mercury TMDL which provides coverage for subsequently listed waters
    • 6 due to individual small lake TMDLs for phosphorus
    • 1 due to coverage in the 2006 Adirondack Lakes Acid Rain TMDL
  • more recent water quality assessments indicating that water quality standards are not being exceeded and uses in these waters are fully supported (13 delistings),
  • assignment to Category 4b for waters where a TMDL is not necessary because the impairment can be addressed using other required control measures (5 delistings),
  • other administrative/tracking actions including the consolidation of smaller lakes into more standard waterbody segments and the correction of previous listing errors (21 delistings), and
  • replacement of waterbodies by more appropriate waterbody segments (2 delistings).

As was noted above, most of the 103 new additions to the list are previously unassessed waterbodies that are not necessarily newly impaired, but have only been recently identified as such. Basins where more recent monitoring/assessment efforts identified the most additional waterbodies/pollutants for listings include the Niagara River/Lake Erie Basin (18 new listings), Lower Hudson Basin (17), the Atlantic/Long Island Sound Basin (17) and the Lake Ontario Tribs Basin (14). Seven (7) new listings included in the Atlantic/Long Island Sound Basin are due to the occurrence and impact of algal growth (Brown Tide) in a number of southern bays. Similar listings for 7 Lake Ontario Shoreline segments are due to weed growth (Cladophora). The impacts of both Brown Tide and Cladophora are not new, but they had not previously been included on the Section 303(d) List due to uncertainty whether TMDLs would be an effective approach to the problem. In fact, these listings are now included on Part 3b (TMDL may be Deferred Pending Verification of Cause/Pollutant) of the List because further study is still needed to determine the exact cause of this impairment and whether TMDLs are the appropriate means to address the problem.

Sources of Impairment

The ten most prevalent causes/sources of water quality impairment in the assessed waters of New York State, are listed below.

  • Urban Stormwater Runoff
  • Aging/Inadequate Wastewater Treatment Infrastructure
  • Nutrient Eutrophication
  • Atmospheric Deposition and Acid Rain
  • Legacy Pollutants in Sediments and Fish
  • Atmospheric Deposition of Mercury
  • Habitat/Hydrologic Modification
  • Nuisance Aquatic Weed Growth and Invasive Species
  • Pathogen Contamination of Shellfish
  • Inadequate Onsite Wastewater Treatment

The graph below shows the frequency for which a specific cause/source is noted as a significant contributing factor in New York State waters. It illustrates the occurrence of each cause/source as a percentage of all waters assessed as impaired (red) or impacted (yellow).

Bar chart showing the frequency of the top 10 problems to water quality in New York