Potential For Using Monthly Flood Forecasts To Utilize Flood Control Storage And Meet Downstream Water Demand Over the Southeastern United States

Anthropogenic disturbances are driving climate change and altering global hydroclimatology, leading to fresh water scarcity threats for a majority of the world's population. Water resource management is critical for environmental, agricultural, and economic purposes. Reservoir management is crucial for water supply control, water quality and environmental health of the given system. The United States Army Corps of Engineers controls most major reservoirs across the Southeastern US; their core objective is to prevent flooding by keeping the flood control pool empty. These operational curves were designed 30-40 years ago with minimal flood forecasting skill, so their relevance should be assessed under existing forecast skill. This operational policy fails to recognize the potential for season-ahead drought or slowly-increasing downstream water demand due to regional population growth. This study investigates the potential and feasibility of utilizing monthly flood forecasts to operate Southeast reservoirs at various elevations for increased water conservation storage without increasing the downstream flood risk. For each proposed elevation increase, three potential forecasts were considered using historical reservoir operations data during the high flow season: a) perfect monthly flood forecast, b) monthly flood climatology and c) flood forecast from Log-Pearson Type 3 (LP3) distribution. Flood risk changes were estimated for each proposed elevation scenario and flood forecasts for each season were estimated based on LP3 distribution. For each storage and forecast scenario, drawdown time to the current reservoir operating levels was computed. Synthesis of results on increased flood risk was assessed based on reservoir purposes, retention time and flood forecasting skill. Opportunities for new reservoirs do not exist, so it is important to utilize skillful forecasts and proactive management techniques to meet the increasing water demand of growing communities.