Oxbow Lake sedimentation along the lower Guadalupe River, Texas

Texas Gulf Coastal Plain Rivers are subject to a dynamic climatic and hydrologic regime. A common feature of Gulf Coast meandering rivers in this region are oxbow lakes. These oxbow lakes exhibit a complex connectivity with the active channel and slowly infill by floods that deposit sediment. Thus, the oxbows serve as an archive of a flood regime throughout time for that particular watershed. This paper reports the results of geomorphic study of flood sediments from two oxbow lakes along the lower Guadalupe River in south-central Texas. Grain size analysis and magnetic susceptibility measurements of the cores, supported by radiocarbon dating and hydrologic data, provide records of the flooding regime. The Guadalupe drains an area of 13,196 km2 in south-central Texas, including the Edwards Plateau and the Gulf Coastal Plain. Sediment data from a recent and older oxbow lake were examined in the context of Guadalupe River hydrology to were analyzed establish a relationship between climatic controls and sedimentation, with the intent of providing inference on paleohydrology of the lower Guadalupe River. In particular, this study examines sedimentary deposits through recent and paleo-oxbow lakes, to compare differences in the sedimentary record of a historical oxbow with the dynamics of a recent oxbow as a modern analog.