Strategy for Sustainable Management of the Upper Delaware River Basin

摘要

The Upper Delaware River represents a valuable ecological resource of New York and Pennsylvania. Recognized as one of the country's most scenic rivers, it is greatly appreciated for its high quality trout fisheries and the variety of outdoor recreation experiences it offers. The river system serves as a water supply for over 8 million people in New York City, via an out of basin transfer, and over 9 million people within the basin. The three New York City water supply reservoirs (Cannonsville, Pepacton and Neversink) are designed to withdraw more than 70% of the average annual volume from the top of the basin at three stems of the Delaware: the West Branch, the East Branch and the Neversink River. Severe reductions and fluctuations in river flows, channel alterations, and landscape modifications resulted in increased water temperature and changes in habitat suitability in the river. As a consequence of these alterations, aquatic fauna in the upper Delaware River have been impaired. This article summarizes (with minor modifications) a report published by Trout Unlimited in 2001 that helped to galvanize efforts toward improvement of management of the Delaware River. The complex ecological alterations caused by unnatural flow conditions, past environmental degradation, and the numerous water supply demands on the basin necessitate a well-defined management scheme to optimize use of the river as a resource and secure its long-term sustainability. Rehabilitation of the upper Delaware River requires both an immediate overhaul of the flow regime below the reservoirs, monitoring and evaluation, and research. In the initial phase, acute deficits should be addressed by increasing base flows, and reducing ramping rates and peak amplitudes. In the second phase, an intensive multidisciplinary study is proposed to quantify limiting ecosystem factors, to better understand groundwater and surface water interactions, and to determine management options. This information will provide a solid basis for evaluatingspecific options and an integrative, long-term management plan for the upper Delaware River.