Do TMDLs Work?

Vermont has been working on revising a lake clean-up budget as directed by the Environmental Protection Agency. What are the chances that the budget will lead to a cleaner lake? Disturbingly low if the plan follows the track of others like it reviewed in a recent General Accounting Office (GAO) report released earlier this year.

For the report, the GAO examined a random sample of 25 long-established (greater than 5 years) pollution budgets for impaired waters known as Total Maximum Daily Loads or TMDLs, and surveyed state officials tasked with carrying out an additional 191 long-established TMDLs. TMDLs allocate allowable pollution loads between sources that require federal permits like factories and wastewater plants, called point sources and all other sources, lumped together as non-point sources. They also require allowances for pollution from future growth and a margin of safety. EPA approved a TMDL for Lake Champlain in 2002 but later revoked that approval. Vermont and EPA are in the process of crafting a new TMDL for the lake.

Of the 25 TMDLs the GAO surveyed, 17 did not show that addressing the identified pollutant would lead to meeting water quality standards; 12 contained vague or no information on actions needed; and 15 did not include provisions for revising the TMDLs. While the TMDLs were effective at eliminating pollution from point sources with 80 percent reaching their goals, they were less effective at eliminating pollution from diffuse non-point sources, and only 20 percent reached these goals. The vast majority of Lake Champlain's pollution problem comes from non-point sources. EPA has limited authority over non-point sources and depends on voluntary measures.

The GAO identified two significant problem areas beyond the authority of states and EPA. First, EPA has no authority to compel private parties to address non-point sources of pollution. EPA's authority is limited to point sources. When Congress revised the Clean Water Act in 1987 they retained the voluntary approach for non-point source pollution, but may need to reconsider this limitation. Second, both states and EPA face budget constraints that limit their ability to address important pollution sources. Cleaning up our nation’s waters will be expensive. GAO recommended that EPA issue new regulations for TMDL development and that Congress consider revising the Clean Water Act’s approach to addressing non-point source pollution.

The GAO also made a series of additional suggestions that could improve TMDLs, some of which could also help on Lake Champlain. Here are some of GAO’s recommendations and how well the draft Lake Champlain TMDL complies with them:

Recommendation: TMDLs should contain a timetable for revisiting them. Lake Champlain: The 2002 Lake Champlain TMDL lacked such a timetable. EPA should be sure to include one in the newer version.

Recommendation: TMDLs should identify site specific project to address water quality pollution. Lake Champlain:  This has been a weakness in the Lake Champlain TMDL. Instead of site-specific project identification, broad policy outlines have been presented. In part, this is due to the massive size of the watershed covered by the TMDL, much larger than those reviewed by GAO. Additionally, Vermont is in the process of developing tactical plans for sub-watersheds within the Lake Champlain watershed. These tactical plans, though not currently part of the TMDL, often contain the site-specific detail GAO has recommended for TMDLs.

Recommendation: TMDLs should contain convincing evidence that impairment is driven by the pollutant for which the TMDL is being developed. Lake Champlain: The Lake Champlain TMDL includes a strong analysis as to why phosphorus is considered the driver of recreational impairment of Lake Champlain. LCC has reservations about focusing narrowly on phosphorus (see next recommendation) but the conclusion is scientifically defensible.

Recommendation: TMDLs should provide evidence that addressing the pollutant in question will be sufficient for the water body to attain its designated use, and TMDLs should be able to consider multiple pollutants. Lake Champlain: This is an area where the Lake Champlain TMDL falls short. Vermont and EPA have focused exclusively on phosphorus as the driver of blue-green algae blooms that limit lake recreation. There are other potential reasons that blue-green algae blooms occur that are not being addressed in the TMDL including other nutrients like nitrogen that promote blooms, climate change which leads to warmer waters that favor blue-green algae, and changes in the aquatic food web brought about by invasive species which may lead to reductions in predators of blue-green algae.

Recommendation: TMDLs should include detailed implementation plans that identify actors and specific locations in need of remediation. Lake Champlain: For the Lake Champlain TMDL, Vermont has developed an implementation plan (TMDLs in some areas of the country completely lack such plans) but it needs more detail about specific actions and places in the landscape where actions will occur.

Recommendation: TMDLs should provide reasonable assurances that actions to address non-point pollution will achieve the expected result. Lake Champlain: EPA lost confidence in the assurances Vermont had put forth that addressing non-point source pollutants would lead to meeting water quality standards. This was a principle reason for rejecting the 2002 Lake Champlain TMDL. EPA will be looking for better assurances in the revised TMDL.

Recommendation: TMDLs should include a monitoring program to address program effectiveness, including monitoring biological indicators, and a description of an adaptive approach to TMDL implementation. Lake Champlain: The Lake Champlain TMDL does include a monitoring program which has been long established. However, the state’s monitoring program is weak in considering the biological indicators that lead to impairment – blue-green algae blooms. The Lake Champlain Committee's blue-green algae monitoring program fills an important gap necessary to determining success of efforts to combat water pollution.

GAO also identified two problem areas beyond the authority of states and EPA. First, EPA has no authority to compel private parties to address non-point sources of pollution. EPAs authority is limited to point sources. When Congress revised the Clean Water Act in 1987 they retained the voluntary approach for non-point source pollution, but may need to reconsider this limitation. Second, both states and EPA face budget constraints that limit their ability to address important pollution sources. Cleaning up our nation’s waters will be expensive. GAO recommended that EPA issue new regulations for TMDL development and that Congress consider revising the Clean Water Act’s approach to addressing non-point source pollution.