Building a Stormwater CIP at Fort Hood

Evan Burn

Fort Hood has numerous drainage and erosion issues throughout the Army Installation. The Fort Hood Main Cantonment Drainage Master Plan was the third in a series of masterplanning efforts to identify drainage issues and propose alternatives in different areas of Fort Hood. The three masterplanning projects combined cover the entire army installation including North Fort Hood, West Fort Hood and the Main Cantonment.

Each study followed the same steps to develop the Stormwater Capital Improvement Program. The first step was a massive data inventory using survey grade information of their stormwater infrastructure and utilities. The inventory of the stormwater infrastructure along with additional channel survey provided the information to model the stormwater system for the entire Army Installation using XPSTORM 2-D and HEC-RAS. The 2-D model focused on the developed portion of the installation and allowed Fort Hood identify areas at risk of flooding and erosion. As the area is generally flat, the 2-D aspect of the masterplan assisted in locating where runoff spills between basins as well as identifying the source of flooding infrastructure. A flooding issue may not be caused entirely by the closest storm drain, but rather due to an upstream deficiency causing bypass runoff to create the flooding concerns. These situations were easily identified through the 2-D analysis.

The HEC-RAS models were used in the undeveloped areas to supplement the 2-D analysis. Open channel floodplains were developed from the HEC-RAS results to identify flooding and erosion issues. Alternatives were analyzed for the entire Installation to alleviate the flooding and erosion concerns that were identified in both the 1-D and 2-D studies. Cost estimates were produced for each alternative.

The final deliverable included written reports and the XPSTORM and HEC-RAS models that Fort Hood can update as future development occurs in the watersheds. The alternatives identified have been added to their capital improvement projects. As improvements are made and new development continues, Fort Hood can use the models to understand how these changes impact drainage upstream and downstream. Fort Hood has benefited from these studies by using the model results to support their flooding concerns. The supporting data assists in obtaining funding to improve their drainage systems. Capital improvement projects identified through these studies have already begun.

This case study was presented at the 2016 Texas Floodplain Management Association Fall Seminar by Lynn Schaub, CPESC, DPW Engineering, Fort Hood, TX; Thomas Caffarel, P.E., CFM, Freese and Nichols; Katie Hogan, P.E., CFM, Freese and Nichols; and Evan Burn, EIT, CFM, Freese and Nichols.