Nonpoint-Source Water Pollution

A recent internal report from the U.S. Environmental Protection Agency states that, in six of the ten EPA regions, pollution from such nonpoint sources as farms and urban streets is the principal cause of water quality problems. Yet EPA policy has focused mainly on point-source pollution, while nonpoint sources so far have been largely uncontrolled.

This assessment came as no surprise to researchers (and others) who, for the past five years, have been developing data and models that distinguish the causes of water pollution from point and nonpoint sources. According to RFF data, about half of the biochemical oxygen demand (BOD) pollutants and nearly all the discharge of suspended solids, phosphorus, and nitrogen originate from rural nonpoint sources. In certain urban areas—some which are highly industrialized—nonpoint sources can account for the majority of certain toxins, including cadmium and lead.

Of course, nonpoint source residuals are accompanied by large amounts of runoff water, so their effect on ambient water quality is much less than what might be expected considering the discharge tonnages alone. Nevertheless, RFF models suggest that the nonpoint contribution to degraded water quality is very significant for most pollution problems, with the possible exception of those due to coliform bacteria and low levels of dissolved oxygen, both of which are associated with BOD loadings in warm summer months under low stream flow and, hence, low nonpoint-source runoff conditions. Importantly, nonpoint pollution may be the principal cause of excessive nutrient problems (eutrophication) in lakes or slowly moving bodies of water.

Federal attitudes and actions

The federal government's attitude toward nonpoint pollution control is characterized by an implicit belief that the problem is best approached with state and local policy initiatives. Thus, in its 1972 version, the Clean Water Act's Section 208 relegated nonpoint pollution to state and local areawide planning processes. But while Section 208 required planning agencies to address nonpoint sources of pollution, it did not mandate specific implementation steps. As a result, this approach certainly was far weaker than that adopted for point sources—mandated discharge permits drawn up under EPA guidelines.

Perhaps in response to insufficient attention to agriculturally related pollution, the 1977 amendments to the Clean Water Act established a new demonstration program in cooperation with the Department of Agriculture. Under this program, the EPA and USDA could contract with farmers to implement "best management practices" designed to minimize agricultural runoff, with the federal government picking up as much as 50 percent of the capital costs. Of course, such incentive programs are successful in reducing pollution only to the extent that farmers perceive that their own self-interests are worth the other 50 percent, plus operation and maintenance expenses not funded as part of the original grant. This may be the case if the farmer is motivated by a desire to preserve topsoil, save on plowing and irrigation costs, conform with state laws, or be a good citizen.

Despite this new provision, the 1977 version of the Clean Water Act failed to secure increased pollution control from nonpoint sources. Indeed, on balance the 1977 amendments may have lessened control. For example, prior to 1977, agricultural pollution originating from irrigation return flows was considered a point source and was subject to mandatory permitting processes. However, in 1977, Sections 208, 402, and 502 were amended to specifically exclude irrigated agriculture as a point source.

Little in the legislative history explains the relatively small attention paid to non-point sources. Obvious possibilities are that it is technically too difficult to control nonpoint sources; that nonpoint pollution is less harmful than that from point sources; or that Congress found it more expedient to focus attention and control efforts at industrial and municipal sources than agricultural and other nonpoint sources.

Although the first two possibilities might appear to have merit, in our opinion the first oversimplifies the true state of affairs. For example, while some nonpoint sources, such as runoff from urban streets, may present severe technical challenges, evidence drawn from EPA demonstration projects and from the experience of farmers using limited-till plowing techniques suggests that large quantities of nonpoint pollution can be controlled fairly easily at relatively low cost. Monitoring the effectiveness of control practices may be more difficult for nonpoint than point sources. Yet, since accurate monitoring has not been an essential feature of current approaches, it is a mistake to ignore nonpoint sources for this reason.

Similarly, even if it were true that point-source pollution contained more harmful constituents than nonpoint sources, that still would not explain the relative neglect of nonpoint pollution: the conventional pollutants targeted in the first few years of the Clean Water Act are common to both sources. In addition, RFF data indicate that often nonpoint sources, especially urban runoff, are the chief source of highly toxic substances in many locations.

On the other hand, the third possibility—that the influence of the agricultural sector on the Congress may account for its relative neglect of nonpoint-source pollution—appears confirmed by recent events. For example, Sen. John Chafee (R-RI) was persuaded by farmers to eliminate language from his suggested amendment to the Clean Water Act that would have mandated nonpoint agricultural controls if voluntary actions proved inadequate. In addition, Chafee dropped language that would have tied other agricultural programs to compliance with EPA agricultural runoff control objectives.

Similar factors, combined with a reluctance to support new (and possibly very expensive) regulatory initiatives may explain the lack of enthusiasm for nonpoint-source pollution policy on the part of the Office of Management and Budget (OMB). Caught between disparate viewpoints, the agency has opted (at the present time) for a cautious approach to nonpoint pollution that will not require new legislative initiatives and would limit the EPA's role to providing technical assistance to state and local governments.

During 1982, however, the EPA did begin a small effort focusing on nonpoint-source issues. The effort's developers held several common thoughts and viewpoints that have shaped it to date and that could provide a basis for different approaches to controlling nonpoint sources in the future.

• In many instances, control of point sources has been pushed to the limit of economic feasibility.
• Substantial cost savings may result from looking at point- and nonpoint-source problems together to meet water quality goals.
• Nonpoint-source water pollution is largely a local or regional (for example, river basin) problem for which a national mandatory control program may not be well suited.
• Millions of dollars have been spent under different federal programs on nonpoint-source research over the last few years. The time may have come to begin using that knowledge.
• However, many unanswered questions remain about the nature and extent of nonpoint-source pollution. For example, environmental effects of chemically similar pollutants from point and nonpoint sources are not fully understood; and the stochastic nature and geographic dispersion of nonpoint-source pollution make it conceptually and practically more difficult to control.

The EPA has begun a number of cooperative studies and demonstration projects to study these aspects of nonpoint source pollution. Built largely on existing information, these studies are regionally dispersed and designed to provide both geographically representative results and examples of where trades between point and nonpoint sources can be implemented. They also will identify unanswered research issues and suggest specific studies to resolve them. These efforts may identify alternatives to traditional regulatory approaches, such as trading between point and nonpoint sources to achieve water quality standards.

The Dillon Reservoir study

A typical example is a case study of the Dillon Reservoir being conducted jointly by the EPA and state and local governments. This reservoir is located in Summit County in the Colorado Rockies, the fastest growing county in the nation according to the 1980 census. Recreation is the basis of the local economy, centered on water-based sports in the summer and skiing in the winter. Completed in the early 1960s and supplying half of Denver's water supply, the reservoir water quality is limited with respect to phosphorus and is in danger of becoming eutrophic; algal blooms in summer are common.

Municipal sewers discharging into the reservoir are its only major point sources of pollution. The sewage undergoes advanced wastewater treatment, but because the reservoir is approaching the limits of its waste-load allocation, the community either must control for more phosphorus at the point sources or take steps to control nonpoint-source pollution—the single biggest contributor of phosphorus to Dillon.

The purpose of the Dillon Project—an actual demonstration of a combination of detention ponds and infiltration pits—is to examine the economic and environmental effects of controlling nonpoint sources of phosphorus in lieu of point sources. Preliminary test results show that, should such nonpoint devices be more widely applied in the Dillon watershed, they would be 85 percent effective in removing total phosphorus at an estimated annual cost savings of several million dollars. Compared to additional point-source control, the project also aims to develop a model permit that might allow pollution trades between point and nonpoint sources of phosphorus to realize these potential savings.

The Colorado Salinity Project

Another example, just getting under way, is the Colorado Salinity Project, a cooperative effort between the EPA and various state agencies. Excessive salinity in the Colorado River affects more than 12 million users of the river in both the United States and Mexico. This project will use the RFF Water Network Model and associated databases to identify sources of salinity, much of which is thought to originate from nonpoint sources. The cost effectiveness of existing salinity control mechanisms will be critically evaluated, and the possibility of instituting selected potential innovations—bubbles, offsets, and others—to achieve better results on the Colorado at less cost will be analyzed. The Network Model then will be used to evaluate the effectiveness of selected policies in controlling salinity.

It is, of course, difficult to predict the implications of these and other studies of nonpoint pollution problem at the EPA. At minimum, they may better sensitize agency decision makers to the extent of the problem. More tangible results may follow if these efforts reinforce the findings of other EPA-funded research undertaken at RFF. In a survey of the extent of nonpoint source pollution and possible policy responses, RFF researchers concluded that, while the problem has unique features, it is not nearly so intractable to policy solutions as many have believed. EPA and RFF research may show that nonpoint-source pollution is more a problem of implementation than of technology.