Protecting dredged material containment levees

The Port of Houston Authority contracted with the engineering and environmental joint venture of Turner, Collie and Braden, Inc. and Gahagen & Bryant & Associates, Inc. (the Joint Venture) to develop the design, plans, cost estimates and specifications for the construction of a demonstration marsh on Atkinson Island. The components of the Joint Venture's design included: (1) construction of a stable, hydraulically-placed containment levee; (2) placement of fill for the marsh itself; and (3) construction of levee erosion protection measures. Due to the expense involved with protecting levees for the ongoing Houston Ship Channel Modernization Project, the BUG decided to utilize the east side of Atkinson Island's containment levees to evaluate cost-effective alternatives to riprap. Prior to this effort, containment levees directly exposed to wave attack were typically protected using expensive structural measures. The BUG evaluated thirteen types of less expensive erosion control techniques using the following parameters: (1) slope stability and bearing capacity; (2) expected wave generation for 20-year storm events; and (3) cost-effectiveness, ease of installation, maintenance and degree of protection as compared to riprap. After an attentive screening, three structural shoreline protection systems were selected for installation along 3,300 feet of the Atkinson Island demonstration marsh levee. The three products listed in the construction documents by the Joint Venture were: (1) a cellular confinement system; (2) fabricated geotextile containers; and (3) a three-dimensional woven geotextile