The Virtual Estuary A GIS tool developed by a team of experts is helping scientists more effectively study complex coastal and estuary systems. Coastal flooding from extreme weather events threatens millions of lives and properties along U.S. coastlines every year. Especially hard hit are areas along the Atlantic Ocean and the Gulf of Mexico where over 60 percent of homes and businesses are within 500 feet of the shoreline. Yet, the ability to explore and study complex coastal environments with accuracy and speed has been limited, if not impossible. Affordable hydrologic models that work well on inland studies simply don’t translate to coastal applications. However, more sophisticated supercomputer-based modeling techniques are cost prohibitive. In a pioneering effort, the St. Johns River Water Management District (SJRWMD) led a team of experts from academia, government, and industry in the development of the Analytical Framework for Coastal and Estuarine Studies (ACES) GIS tool, one of the first comprehensive coastal and estuarine tools. Still under development, ACES is designed to help scientists accurately monitor and manage the health of a complex estuary from within the Arc Hydro hydrologic environment. [Arc Hydro is a data model template for use with water resources applications that has been developed by Esri in collaboration with key state, national, and international contributors.] This tool has been used to support estuarine and coastal studies for the Guana/ Tolomato/Matanzas Estuary, also a National Estuary Research Reserve for SJRWMD, as well as water quality studies in the Gulf of Mexico. [The National Estuarine Research Reserves are “living laboratories” that help researchers better understand coastal communities and find methods for dealing with the challenges these areas face.] Cooperative Development SJRWMD is responsible for regulating water use and protecting wetlands, waterways, and drinking water supplies along Florida’s sensitive eastern coastline from Fernandina Beach to Vero Beach. The agency’s Surface Water Quality Monitoring (SWQM) has used Arc Hydro to develop specialized hydrologic tools such as an automated pollution load screening model and a drainage area spatial data summary tool. 30 ArcUser Spring 2010 New GIS tool for exploration and analysis By Sandra Fox, St. Johns River Water Management District, and Stephen Bourne, PBS&J In this portion of the estuary displayed in ArcScene, the high tide polygon (red line) and low tide polygon (solid dark blue) along with a digital elevation model (DEM) of the area Yet, while greatly beneficial, these hydrologic tools were unable to account for tidal influences, which directly impact water quality in estuarine waters. This limited the agency’s ability to accurately manage water quality throughout the region. SJRWMD put together a technical team to develop ACES that included experts from SJRWMD, University of Florida, The Nature Conservancy, U.S. Geological Survey, and PBS&J, a consulting firm. The agency also put in place an expert review team that would be responsible for evaluating the end product developed by the technical team. The review team included the members from the Center for Research in Water Resources at the University of Texas, Austin; U.S. Army Corps of Engineers’ Engineer Research and Development Center; and PBS&J. The technical team’s first task was to establish a master plan for the tool development from proof of concept to production. SJRWMD stipulated that the tool must be applicable to all SJRWMD estuaries and include existing GIS-based tools and enhanced Arc Hydro geodatabases developed by SWQM. Goal-driven brainstorming sessions helped keep the technical team on track throughout the development process. The initial brainstorming sessions and literature review focused on the nature of an estuary, estuarine hydrodynamics, estuarine classification, existing GIS-based modeling technologies for estuaries, and synthetic modeling of water quality in estuaries. The team found that the first step in approaching the study of estuaries was the creation of a GIS-based workbench tool that could integrate multiple sources. Water in coastal areas frequently comes from multiple sources. These might include surface water flow, incoming tides, manmade waterways, and even in some cases groundwater. The tool had to allow for the creation of virtual estuaries and estimation of bulk parameters of the estuaries and facilitate development and integration of other models into the same framework. Conceptual Controls In the initial development phase of the ACES project, the technical team developed an estuary control volume conceptual model that connects features in the estuary physical model with elements contributing to the control volumes such as waters from coastal bases, oceanic constituents, riverines, and intracoastal www.esri.com