LEVERAGING WATER QUALITY ASSESSMENT RESOURCES — WHY TMDLS AND SWAPS SHOULD BE PERFORMED TOGETHER

There are strong similarities between the Source Water Assessment Plans (SWAPs) required under the Safe Drinking Water Act and Total Maximum Daily Loads (TMDLs) required for many waterbodies under the Clean Water Act. Both SWAPs and TMDLs require water quality assessments, water quality modeling, hydraulic calculations, pollutant source assessment, and public notice, and they are often prepared on the same waterbodies. Nonetheless, such assessments are often performed separately, sometimes by different agencies.By 2003, SWAPs must be performed to cover the 170,000 public water supplies in the U.S. Over the next decade, upwards of 40,000 TMDLs will be required on impaired waterbodies in the U.S. Cost estimates vary, but the cost of of SWAP development will exceed 100 million and TMDL development costs are expected to exceed 400 million. Currently, there is some federal funding for SWAPs but no specific federal funding for TMDL development.The difficulty of finding the financial and technical resources to perform these assessments separately make a strong case for leveraging funds in the SWAP program to help support TMDL development. In addition, a combined assessment would allow for a more comprehensive look at water resources within a state. Because of the high degree of overlap in technical requirements, it is felt that combining SWAPs and TMDLs could be very cost-effective for surface water supplies in many states.