Policy implications of aging and manipulated river systems case study: Black Warrior River

Abstract

This dissertation is a policy analysis of lateral connectivity issues on aging and manipulated river systems. The research focuses on associated issues of ecosystem health and human impacts as illustrated in a case study of Alabama's Black Warrior River. The study area on the Black Warrior River, river mile 213 to 292, is representative of other manipulated river systems throughout the United States. The construction of two federally owned locks and dams within the study area created a multi-use inland waterway due to the formation of lentic environments upstream of the regulating structures. The inland waterway's historic management was largely one-dimensional and main channel-oriented. This one-dimensional approach caused a significant deterioration of lateral connectivity. Between 1965 and 2006, the number of open or marginally open entrances to off-channel areas declined from 251 to 119. Open and marginally open off-channel areas decreased 1,125 acres between 1965 and 2006, representing a 26 percent decline. Overall, 643 off-channel acres, regardless of status (i.e., open, marginally open, or closed), were lost during this timeframe, representing a 15 percent decline, and the average and median size of off-channel areas also declined 30 and 53 percent respectively. The decline in lateral connectivity resulted in environmental impacts to the area's fishery and differential effects to a range of stakeholder groups. Policy alternatives were developed and their social impacts assessed to provide decision-makers within the study area and across the United States with options to address lateral connectivity issues.