The Clean Water Act requires states (or EPA if a state refuses to play ball) to set water quality standards for each stream sufficient to protect the purposes, e.g., fish, drinking, and swimming, for which the water is used. The Act also bans dumping pollutants from a pipe into a stream without a permit. Permits set limits on the amount of each pollutant that can be dumped. The pollution allowance must ensure that the water quality standards are met throughout the stream.
But, many pollutants, like turbidity, come from other sources than pipes, such as run-off from farms and forests. Congress has been unable to agree upon a regulatory tactic for dealing comprehensively with these so-called non-point pollution sources. Instead, the Clean Water Act requires states to do planning.
The “Total Maximum Daily Load” planning process has three steps. First, states identify streams where water quality standards are not being met. Second, for these “water quality limited” streams, the state calculates a ceiling on the amount of each problem pollutant that can enter the stream. Third, the state gives each source, both point and non-point, a pollution allocation, the sum of which must be less than the ceiling. Fourth, the state writes up a “TMDL report” for EPA’s approval. The report must explain the activities the state will carry out to reasonably ensure that the TMDL allocations are not exceeded. These actions can include clamping down on point-source discharges, imposing “best management practices” on non-point source activities, land use restrictions, or the writing of more plans.
The TMDL planning process is rife with fascinating politics and backroom dealings. Point-source polluters, such as factories and sewage treatment plants, know that their pollution is measured and the limits enforceable in federal court by the state (or private citizens if the state or EPA fails to do so). But most non-point source polluters face no such regulatory hammers because most states have few, if any, mechanisms to enforce best management practices, and EPA has none.
This imbalance in regulatory enforcement means that point-source polluters take the hindmost. For example, if a stream is already at its maximum load for temperature, it will be almost impossible for a new power plant, such as a biomass boiler, to be built if it discharges hot water to the stream. If a stream is at its limit for E. coli bacteria, it will be very tough for an animal feed lot to renew its permit to discharge manure-laden waste water, which will force the feedlot to find other disposal strategies such as spraying its cow crap on cropland (note that the non-point source run-off from cropland is not as tightly regulated and not subject to Clean Water Act citizen suits).
The TMDL process goes on unnoticed by the general public and is of interest to only a handful of citizen-based organizations. But the process is tightly scrutinized by point-source polluters who lobby for better BMPs so that more pollution load can be allocated to new factories, while non-point polluters (primarily farmers, ranchers and timberland owners) seek to keep BMPs lax.