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Spatial and functional characterization, identification and assessment of isolated wetlands in Alachua County, Florida, USA - GIS and remote sensing techniques
Reif, M., R. C. Frohn, C. R. LANE, B. C. AUTREY, AND E. D'Amico. Spatial and functional characterization, identification and assessment of isolated wetlands in Alachua County, Florida, USA - GIS and remote sensing techniques. Presented at ESRI Conference, San Diego, CA, August 04 - 08, 2008.
Isolated wetlands occur in many area of the US, and although they are relatively common, they are a resource not yet thoroughly understood by the scientific community. Isolated weltands have received increased attention recently, due to the 2001 Solid Waste Agency of Northern Cook County vs. U.S. Army Corps of Engineers (SWANCC) Supreme Court ruling which reduced federal protection of isolated wetlands under Section 404 of the Clean Water Act. In the aftermath of this decision, scientists and researchers are attempting to gain a more thorough understanding of these weltnad resources, their characteristics, and value. Having accurate information on the extent of isolalted wetlands is a first step toward understanding and characterizing these systems and is an integral part of identifying their function in the landscape.
In this study, Geographic Information Systems (GIS) and remote sensing mapping techniques were developed to identify the locations of isolated wetlands in Alachua County, FL, a 2510 sq km area in north-central Florida with diverse geology and numerous isolated wetlands. The results of the stand-alone and combined GIS and remote sensing analyses were assessed by comparing the mapped isolated wetlands to an accuracy dataset, using an "intersection" approach. The combined GIS and remote sensing method performed the best of all methods developed, with producer accuracies ranging from 93-100% and user accuracies ranging from 86-95%, depending on wetland size. In addition, both the stand-alone remote sensing method and the combined GIS/remote sensing method were especially successful at identifying smaller isolated wetlands, down to 0.5 acre in size, which can be difficult and time consuming to map using aerial photointerpretation. Using Light Detection and Ranging (LIDAR) imagery, wetland bathymetry and volume studies are currently being conducted o the identified isolated wetlands to determine relationships between wetland type, area, and water storage capacity. This hydrological modeling will be used to identify isolated wetland contribution to hydrologic dynamics and downstream condition and conduct landscape-level analyses of the ecosystem services provided by these aquatic systems.