Recent Wetland Losses at the GSU Marsh Restoration Site, Neches River Valley

Texas Parks and Wildlife Department's (TPWD) plans to restore a marsh in the lower Neches River valley south of the Gulf States Utilities (GSU) power plant, an area of known historical marsh loss due partly to subsidence and faulting, emphasized the need to investigate potential long-term impacts of subsidence on the marsh site (fig. 1). Marsh restoration efforts could fail, however, if the area continues to subside at a rate that exceeds marsh vertical accretion. Determining whether the GSU area is subsiding at a rate higher than that of the surrounding landscape could be answered by benchmark releveling surveys across the area, but those surveys have been conducted only across regions more inland (Ratzlaff, 1980). Although site-specific releveling surveys would provide the most quantitative and reliable data regarding subsidence, lack of time and funding for establishing benchmarks and conducting releveling surveys over a sufficient period of time prevented such an approach. Consequently, potential future marsh loss as a result of submergence had to be estimated by other means.