Executive Summary

Castle County, Delaware, is a valuable source of drinking water (i.e., used by 130,000 people) and possesses outstanding scenic, wildlife, recreational and cultural value. It was the first watershed in its entirety (280 km2) to be designated as a National Wild and Scenic River. The Stream Watch Program was initiated back in 1991 because little was known about current stream conditions in the White Clay Creek (WCC) watershed and because of concerns about rapid land development in the area. The goals of this study were to evaluate water quality in WCC and its tributaries using aquatic macroinvertebrates, and make data available to encourage efforts to improve and/or protect water quality in WCC. Aquatic macroinvertebrates (insects and non-insects such as worms and mollusks) are a cost-effective, commonly used, and widely accepted tool in water quality monitoring programs. Macroinvertebrate sampling occurred for ~9-15 yrs from 1991 to 2008 at 18 sites located throughout the WCC watershed. Rating Water Qualit