Alternatives to Doing a Dam Thing

Abstract

Population projections for the City of Raleigh, NC indicate a shortfall in long-term raw water supply requirements given current service area demands. Raleigh is proposing the development of a new reservoir to meet midterm needs; however, the reservoir is a costly project with relatively short-term returns and is an environmentally sub-optimal solution. This report proposes four unique adaptive management options to Raleigh’s existing reservoir, Falls Lake, as alternatives to a new reservoir: Permanent flood control pool reallocation, dynamic reservoir management, permanent sedimentation pool reallocation and guide curve flexibility. Considering system risk, costs, ability to generate additional water supply and environmental impacts, we recommend the combination of sedimentation pool reallocation and a flexible guide curve be explored to increase the city’s water supply allocation from Falls Lake. Current static management of water supply sources is ill equipped to adapt to dynamic climatic conditions and human development which may lead to increased risk and vulnerability for the communities that rely on similar reservoirs for municipal water supply and flood control