purposes of drinking water protection, consideration of the relative cost-effectiveness of different strategies merits attention. For example, to what extent should limited financial resources be allocated between water system upgrades and source water protection in the region?
The use of cost-effectiveness as the primary method of evaluating options for achieving water quality objectives in the region is recommended. It should include an analysis of incremental costs to achieve elimination of low-probability contamination events. The committee also recommends the use of benefit-cost analysis in the evaluation of water quality improvement projects in the region, and in helping to set priorities. Although “state-of-the art” studies can be very expensive, it may be possible to gain useful information using “lower cost” methods. For example, “benefits transfers” is a method for estimating benefits of environmental quality improvements using results from other regions. The EPA’s (2000b) Guidelines for Preparing Economic Analyses describes methods and procedures for cost-effectiveness and benefit-cost studies.
Decision makers in the region may want to apply criteria beyond long-term cost-effectiveness and benefit-cost analysis to project evaluation. They may also have interest in metrics of performance beyond costs, benefits, or water quality indicators, such as equity, social justice, and other social objectives. To the extent that this is the case, multicriteria methods offer tools for systematic evaluation of water quality improvement projects and related decisions when there are multiple competing objectives. A brief introduction to the array of methods is presented in Janssen and Munda (1999).
As the CWARP process is being implemented, it is essential that it be integrated with the ongoing process of establishing total maximum daily loads (TMDLs) for impaired streams being conducted by PADEP under requirements of the Clean Water Act. There are many parallels between CWARP and the process for establishing TMDLs. A TMDL defines the pollutant load that a waterbody can assimilate without causing violations of its water quality standards. The term TMDL also refers to a plan for those waters in violation of their water quality standards, in which the excess pollutant loading is allocated between contributing point sources and nonpoint sources and subsequent actions are taken to control and eliminate these excesses.
Although the TMDL program originated from the Clean Water Act (Section 303d), it was largely overlooked during the 1970s and 1980s as states focused on controlling point sources of pollution through compliance with NPDES permits (NRC, 2001). Beginning in the 1980s, citizen lawsuits forced EPA to develop guidance for the TMDL program, which is now considered pivotal in achieving the nation’s water quality goals.
The NRC (2001) review of the scientific basis of the TMDL program recommended that the program meet certain objectives, some of which are also an integral part of the CWARP approach recommended in this report. These objectives include the following:
improve the condition of waterbodies as measured by attainment of designated uses;