Identification and Remediation of Polluted Waters Impeded by Data Gaps
T-RCED-00-131: Published: Mar 23, 2000. Publicly Released: Mar 23, 2000.
- Full Report:
Pursuant to a congressional request, GAO discussed the data that the Environmental Protection Agency (EPA) and the states have for making critical water quality decisions required by the Clean Water Act, focusing on: (1) the adequacy of the data for identifying waters for states' 303(d) lists; (2) the adequacy of data for developing total maximum daily loads (TMDL) for those waters; and (3) key factors that affect the states' abilities to develop TMDLs.
GAO noted that: (1) only 6 states reported that they have a majority of the data needed to fully assess their waters, raising questions as to whether states' 303(d) lists accurately reflect the extent of pollution problems in the nation's waters; (2) while the state officials GAO interviewed felt confident that they have identified most of their serious water quality problems, several acknowledged that they would find additional problems with more monitoring; (3) states reported that they have much more of the data they need to develop TMDLs for pollution problems caused by point sources than by nonpoint sources; (4) states can more readily identify and measure point sources of pollution because these sources generally discharge pollutants through distinct points, such as pipes; (5) conversely, nonpoint sources are difficult to identify and measure because of their diffuse nature; (6) as a result, developing TMDLs for pollution problems caused by nonpoint sources often requires additional data collection and analysis; (7) only three states reported having a majority of the data they need to develop TMDLs for these types of problems; (8) states reported that they have been developing TMDLs for waters polluted by point sources for many years and, therefore, have expertise in analyzing these types of pollution problems; (9) in contrast, however, states told GAO that their ability to develop TMDLs for nonpoint sources is limited by a number of factors; (10) states overwhelmingly cited shortages in funding and staff as the major limitation to carrying out their responsibilities, including developing TMDLs; and (11) in addition, states reported that they need additional analytical methods and technical assistance to develop TMDLs for the more complex, nonpoint sources of pollution.