Unit 17 and Unit 18 Lecture Notes - Clean Water: Point Source Control and Nonpoint Source Control

The major water pollutants regulated under the Clean Water Act are pathogens, organics, toxic organics, nutrients, heavy metals, and sediment. Pathogens are obviously a problem any time humans or animals can be expected to come in contact with the water. Organics are organic compounds of various sorts. In and of themselves they do not cause a problem; however, as they decompose they reduce oxygen levels in water to such an extent that aquatic organisms may not survive. Toxic organics include substances such as some pesticides as well as other chemicals that have toxic characteristics. These include some of the worst industrial pollutants such as PCBs and dioxin. Nutrients (phosphorus (P) and nitrogen (N)) lead to eutrophication of bodies of water. N and/or P, if the limiting factors in a body of water, may lead to rapid algae growth. When it dies and decomposes it reduces oxygen in the same way that organics do. Excess N and/or P may change the ecological balance of a body of water leading to the growth of toxic organisms such as Pfiesteria, discovered by N.C. State Professor JoAnn M. Burkholder. Heavy metals, (e.g., mercury, cadmium, and lead) are toxic and build in the food chain where they can harm people who eat aquatic organisms. In terms of volume, sediment is the single greatest pollutant. Sediment can alter stream channels and make the environment unsuitable for either recreation or aquatic organisms.

The Clean Water Act divided surface water pollution into point and nonpoint sources. Point sources are defined as easy to identify the source and concentrated while nonpoint sources are defined as hard to identify the source and diffuse. The classic example of a point source is a pipe from a factory that is dumping waste directly into a stream. The classic nonpoint source is runoff from a pasture. There is no bright line that separates point from nonpoint sources. Nonetheless the distinction has enormous regulatory consequences. Point sources must obtain a National Pollutant Discharge Elimination System (NPDES) permit while nonpoint sources are scarcely regulated at the federal level. The NPDES permit programs are delegated to the states. Each discharger's permit specifies in detail the pollutants that may be discharged. Permits must be renewed every five years. Both the initial permit and the renewal are subject to public comment. Large livestock operations that maintain livestock off of vegetation for 45 or more days per year are defined to be Confined Animal Feeding Operations (CAFOs). A CAFO is deemed to be a point source and is required to obtain a NPDES permit even though it may not currently be discharging to a surface water.

The NPDES program is a performance standard system. Performance standard systems require permittees to meet a specific performance standard without regard to the actual effect of the pollutants that they are discharging. It may be that the pollutants discharged are causing serious harm to the water. In such a case the public (other users of the water) are being forced to bear part of the polluter's cost of waste disposal. Or it may be that the polluter would have no impact even if not required to meet the performance standard. In such a case no one is benefiting from the money that the polluter pays to clean up his waste stream. That money that benefits no one is referred to as a deadweight loss.

Deadweight losses can be avoided only with a system based upon ambient water quality standards. The Clean Water Act also contains provisions for developing ambient water quality standards. This effort also is delegated to the states. Standards are based upon the uses that a body of water is expected to support. Thus a stream in the coastal plain can accept more waste than a stream in the mountains that is expected to support a recreational trout fishery since trout are more sensitive to most pollutants then warm water fishes. For waters that are impaired (have failed to meet ambient water quality standards) states are expected to establish total maximum daily loads (TMDLs) for each pollutant that impairs the water. Although the TMDL program was part of the Clean Water Act of 1972, the states neglected it and the EPA did not force the issue. Citizen suits against EPA, beginning in the 1980s, have brought the issue of TMDLs to prominence.

The NPDES program has worked very well to clean up the worst sources of water pollution. However, it is now apparent that the NPDES program alone will not solve the problem. Thus there has been a shift toward focussing on the TMDL program. TMDLs can be used to allocate wasteloads among both point and nonpoint sources of pollution. Although it is not clear the extent to which nonpoint sources can be regulated under the TMDL program, it is clear that most states have separate state authority under which nonpoint sources may be regulated. Thus regulation of nonpoint sources has shifted from voluntary, cost-share programs to mandatory regulation of the activities of nonpoint sources.

Ambient water quality programs are expensive to operate. Water must be monitored through sampling and tests. These are listed in the overheads. Although ambient water quality programs can avoid deadweight losses they require much more data to operate. These programs are also far more complex than performance based systems. Those regulated may be concerned about fairness because it is often difficult to associate the discharges of a particular polluter with effects on water quality. The NPDES program has the advantage that there is greater certainty for both the regulator and the regulated.

Last Updated: May 6, 2002 12:54