Hydraulics and Stability of Five Texas Inlets

Existing data on tides and currents of five Texas inlets (Freeport Harbor Entrance, San Luis Pass, Galveston Bay Entrance, Rollover Pass, and Sabine Pass) are analyzed to determine the hydraulics of the inlet-bay systems. The effects of the hydraulics and other factors on inlet stability are also examined. Significant increases in both range and level will occur through 1986, when maximum values may cause inundation of areas which have only recently subsided. Due to the small tidal prism of Freeport Harbor Entrance, frequent dredging is required. San Luis Pass is stable geographically, although it has been increasing slowly in size over the past hundred years. The volume of the ebb and flood tidal deltas has remained almost constant in recent years, and parts of these deltas would be good sources for beach-fill material. Such sources are also found at Galveston Bay Entrance, where jetty construction produced extensive areas of accretion on the adjacent beaches. Historically, increasing cross-sectional area at Galveston resulted in corresponding increases in Galveston Bay tidal range, and ebb discharges during 'northers' contributed significantly to natural scouring of the channel. Although small, Rollover Pass affected adjacent bay and beach characteristics in a pattern similar to that found at large inlets with manmade improvements. Complex patterns of flow occur within the Sabine Pass inlet-bay system, but strong ebb discharges during winter northers undoubtedly enhance channel maintenance.