A rapid watershed assessment approach for assessing the condition of small, coastal watersheds: Protocol and case study

Abstract

Human population pressures in coastal drainage basins have increasingly contributed to degraded estuarine habitats. Yet, there are no approaches for rapidly characterizing watersheds and for identifying sources of environmental degradation that affect estuarine habitat and water quality. A rapid watershed assessment (RWA) protocol is described that uses 15 indicators from both contributing watersheds and receptor estuaries to assess coastal watershed condition. The protocol was applied to five small, coastal watersheds to illustrate strengths and limitations of the approach and its sensitivity in quantifying differences in condition among the watersheds.

The RWA found that the poor condition of the tested coastal watersheds were due to both problems in the contributing watersheds (primarily due to agriculture and field drainage ditches) and problems in the receptor estuaries (primarily due to pollution leading to closed shellfish beds and channel maintenance detrimentally affecting benthic habitats). Indicator data were robust enough to differentiate variations in condition among indicators and sufficient to identify problems that needed to be addressed in contributing watersheds and receptor estuaries. Thus, indicator output can be used to diagnose problems in ways that can guide planning at a small watershed scale, identify ways to minimize future impacts, and help prioritize strategies for improving or enhancing current conditions. Because the RWA protocol integrates the types of data that are readily available for small estuaries, it provides a useful framework that could be adapted for use in small coastal watersheds and subestuaries elsewhere.