Erosion Control and Environment Restoration Plan Development: Matagorda County, Texas. Phase 2: Preliminary Design




Rosati, James III
Frey, Ashley E.
Thomas, Robert C.

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United States Army Corps of Engineers. Engineer Research and Development Center


A two-part study was conducted to identify structural methods to reduce beach erosion in Matagorda County, Texas, at Sargent Beach and along Matagorda Peninsula, east of the Mouth of the Colorado River (MCR). Phase 1 (Thomas and Dunkin 2012) investigated the coastal processes of the region and introduced several structural alternatives to reduce erosion at both locations. Preferred alternatives included a groin field with beach fill east of MCR and segmented breakwaters to protect Sargent Beach.

This report explains further coastal processes with a short-term, recent sediment budget, describes recent studies, provides higher-resolution numerical modeling, and includes preliminary design of the selected alternatives. Numerical models were applied to evaluate structure performance and to prepare for preliminary design of selected structural alternatives. Calibration for one of those models, GenCade, was updated based on model improvements and additional data. A Coastal Modeling System (CMS) numerical model was developed and validated against water level data.

Near MCR, the preferred alternative included three groins 1,800 ft apart with optional levels of beach fill. Several breakwater alternatives were analyzed at Sargent Beach. Complex physical processes and potential risk associated with segmented breakwaters led to the recommendation of a demonstration project consisting of a set of 10 breakwater segments northeast of Mitchell’s Cut. Design and construction of additional segments will depend on demonstration project results. Preliminary design and feasibility analysis was conducted for each of the selected alternatives. A field monitoring plan for both sites is suggested to reduce uncertainty with future design of shore protection.



beach erosion, Matagorda County, Texas, engineered beaches, dredging, Texas