Coastal Spine System; Interim Report

Prepared by:

S.N. Jonkman (TU Delft), K.T. Lendering (TU Delft), E.C. van Berchum (TU Delft), A. Nillesen (, L. Mooyaart (RHDHV), P. de Vries (RHDHV), M. van Ledden (RHDHV), A. Willems (Iv Infra), and R. Nooij (Iv Infra)

Publication Date:

June 20, 2015

The Galveston Bay area is at significant risk from hurricane-induced flooding. Over the past years the concept of the Coastal Spine (also named Ike Dike) has been developed as a solution to reduce flood risks for the region. The main aim of the coastal spine is to limit the inflow of hurricane surge into the Galveston Bay and thus protect Houston, Galveston and other communities around the bay.

The aim of this report is to synthesize the design work that has been done on the Coastal Spine system and provides an indicative and preliminary estimate of the costs of the system. Figure 1 presents an overview of the system and its main elements as discussed in the chapters in this report. The barrier includes storm surge barriers in the Bolivar Roads inlet and San Luis Pass. The total length of the coastal spine in Figure 1 is 94 kilometers (58.5 miles), consisting of 90 km (56 miles) of land barriers and 4 km (2.5 miles) of storm surge barrier. 20 km (12.5 miles) of the land barrier, along the Bluewater Highway, is still optional and added to provide a closing solution. Also, the eastern end of the land barrier near the community of High Island has to be determined and this section is therefore dashed as well. The exact length and layout will have to be optimized in future investigations.

The main function of these barriers is to prevent inflow of the hurricane surge into the bay through these inlets. The designs have been based boundary conditions for navigation and environmental flow as to minimize impacts on these functions. Other important elements of the system are the land barriers, which aim to prevent and limit overland flow into the bay. Various initial design concepts for the land barrier have been explored based on requirements for engineering performance and landscape integration.