Benefits of water quality policies: the Chesapeake Bay

Abstract

The Chesapeake Bay is a unique and treasured natural resource. It is the largest estuary on the Atlantic coast and one of the largest estuaries in the world. The Chesapeake drains portions of six states: Virginia, Maryland, Delaware, Pennsylvania, New York, and West Virginia and the District of Columbia. As testimony to its importance, the US Congress issued a directive in 1976 to the Chesapeake Bay Program (CBP) to examine and identify the factors that were altering the conditions of the Bay. Nutrient delivery to the Bay, which has increased dramatically over time, was identified as one of the factors and has been the primary focus of research and policy efforts related to achieving water quality improvements. The purpose of this paper is to estimate the benefits of water quality legislation in the Bay region from 1972, the year the Clean Water Act (CWA) was promulgated, to 1996. Nutrients, nitrogen and phosphorous, are the dominant criteria addressed by this case study. Benefits are assessed from a ‘with–without’ perspective. That is, 1996 water quality is compared with what it would have been in 1996 without the CWA and related legislation. The US EPA CBP Watershed and Water Quality Models were used to determine the distribution of nutrient loadings from point and non-point sources and characterize water quality. Modeling results indicate that conditions in the Bay are improved in some areas for some pollutants. Total phosphorus has decreased dramatically from ‘without’ concentrations in all major tributaries and segments of the Chesapeake Bay. The monetized annual boating, fishing, and swimming benefits of water quality improvements in the Chesapeake Bay range from $357.9 million to $1.8 billion. 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 Watershed, are not included in this analysis. As such, this range likely underestimates the true benefits of Bay water quality improvement.