Date of Award
Master of Science - Environmental Sciences
Dr. Hans M. Williams
Dr. Brian P. Oswald
Dr. Daniel R. Unger
Plans for the construction of Lake Naconiche, located in northern Nacogdoches County, included a monitoring project to demonstrate at least 176 acres of land adjacent to the lake would be converted into wetlands. The purpose of the study was to evaluate the creation of wetlands around the lake and establish a benchmark of vegetation composition and condition for future comparison. Eight locations, placed where the majority of wetlands were expected to form, were chosen for monitoring from the shoreline at 348 feet above mean sea level (ft MSL) to the county fee take line at 357 ft MSL.
Shallow groundwater monitoring wells were installed along transects perpendicular to the shoreline at all sites to monitor hydrologic changes in order to project how much land around the lake will convert to wetland. Two vegetation sampling techniques, a plot-based method and the line-intercept method, were used at each site to determine baseline species composition along an elevation gradient in areas predicted to become wetlands. Normalized Difference Vegetation Index (NDVI) values at each site were compared along an elevation gradient to determine the baseline physiological condition of vegetation in areas predicted to become wetlands.
Groundwater monitoring revealed that the water table at monitoring sites around the Naconiche and Telesco branches consistently reached an elevation of 352 ft MSL during the growing season. Using the elevation of 352 ft MSL as an estimate for the entire lake, an area of approximately 188 acres of land adjacent to the lake was projected to become wetlands. Vegetation monitoring revealed that the majority (>50%) of species in areas predicted to become wetlands are well adapted to saturated conditions based on wetland indicator statuses determined by the U.S. Army Corps of Engineers (USACE). Vegetation analysis also revealed that elevation does not have an observable influence on species composition. Evaluating NDVI values showed no difference in vegetation condition along an elevation gradient. It is expected that vegetation closer to the shoreline will eventually show signs of stress due to prolonged periods of saturation and that species that are more tolerant of seasonal flooding will replace the existing species.
Urbanovsky, Amy L., "Initial Wetland Hydrology and Vegetation Composition in Predicted Wetlands Adjacent to Lake Naconiche, Nacogdoches County, Texas" (2016). Electronic Theses and Dissertations. 46.
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