Benefits of water quality policies: the Chesapeake Bay

The Chesapeake Bay is a unique and treasured natural resource. It is the la rgest estuary on the Atlantic coast and one of the largest estuaries in the world. The Chesapeake drains portions of six states: Virginia, Maryland, D elaware, Pennsylvania, New York, and West Virginia and the District of Colu mbia. As testimony to its importance, the US Congress issued a directive in 1976 to the Chesapeake Bay Program (CBP) to examine and identify the facto rs that were altering the conditions of the Bay. Nutrient delivery to the B ay, which has increased dramatically over time, was identified as one of th e factors and has been the primary focus of research and policy efforts rel ated to achieving water quality improvements. The purpose of this paper is to estimate the benefits of water quality legislation in the Bay region fro m 1972, the year the Clean Water Act (CWA) was promulgated, to 1996. Nutrie nts, nitrogen and phosphorous, are the dominant criteria addressed by this case study. Benefits are assessed from a 'with-without' perspective. That i s, 1996 water quality is compared with what it would have been in 1996 with out the CWA and related legislation. The US EPA CBP Watershed and Water Qua lity Models were used to determine the distribution of nutrient loadings fr om point and non-point sources and characterize water quality. Modeling res ults indicate that conditions in the Bay are improved in some areas for som e pollutants. Total phosphorus has decreased dramatically from 'without' co ncentrations in all major tributaries and segments of the Chesapeake Bay. T he monetized annual boating, fishing, and swimming benefits of water qualit y improvements in the Chesapeake Bay range from $357.9 million to $1.8 bill ion. These benefit estimates represent use values for persons living in the District of Columbia, and portions of Maryland and Virginia. Residents of Delaware, New York, and Pennsylvania, which are also part of the Bay Waters hed, are not included in this analysis. As such, this range likely underest imates the true benefits of Bay water quality improvement. (C) 2001 Elsevie r Science B.V. All rights reserved.