Deltaic and associated riverine deposits near the mouths of rivers that discharge into estuaries along the Texas coast are the sites of extensive salt-, brackish-, and fresh-water marshes that are essential components of biologically productive estuarine systems. These bay-head depositional features are constructed primarily by fluvial sediments, sediments transported and deposited by the major rivers that enter estuarine waters. The loss of over 10,000 acres of wetlands in alluvial and deltaic areas of the Neches (White and others, 1987) and San Jacinto Rivers (White and others, 1985) emphasized the need to examine in more detail the processes that establish and maintain, as well as degrade, these important natural resources along the Texas coast.