Basin-Wide Water Budgeting Using an Integrated Model

Abstract

Integrated surface water/groundwater models have been used extensively for water budgeting and water resource allocation projects in Florida. Is a similar modeling approach viable in Georgia? The Caloosahatchee River Basin is a river system that is used heavily by agriculture and is under intense urban development pressure and drains to an important saltwater estuary. Water managers are faced with the challenge of providing sufficient freshwater for competing (irrigation, potable water, and ecological) water needs. Future plans suggest that the volume of surface water and ground water historically used to meet these needs will be greatly reduced in the future. How will water managers meet the challenge? The South Florida Water Management District (SFWMD) has utilized the integrated surface water/groundwater model, MIKE SHE, to evaluate water demands and budgets for existing and future conditions. This tool gives the SFWMD the ability to evaluate the impact of alternative water management strategies within a single computational environment. This tool has been used to answer many questions within the Caloosahatchee River Basin. Typical questions include: 1) If we reduce flows to the Caloosahatchee River, can we still provide enough water to the estuary? 2) If we build a reservoir, what impacts would we expect to see in the groundwater and the surrounding stream network? 3) If we add an irrigation pump to this stream, will it impact the nearby wetlands? 4) What is the irrigation return flow to streams from irrigation wells? 5) How can we manage water so we don’t cause flooding in urban areas? 6) What is the hydro-period of the wetland restoration project we are implementing?