This project involved the development of a Drainage Master Plan for the City of Southlake that addressed street flooding issues in numerous areas of the City and an associated Capital Improvements Plan. The City encountered a rapid rate of development with many new subdivisions and businesses being constructed over a short period of time. As a result, the City’s drainage patterns and storm water runoff were significantly affected. Prior to hiring KSA Engineers, Inc., the City had established a list identifying and ranking the most critical locations on the major creeks within the City. KSA was contracted to prepare hydrology and hydraulic models of the 26.5 miles of channels to more accurately locate problem areas and identify possible solutions. HEC-HMS and HEC-RAS programs were used to develop the models. These models were used to indicate the severity of the existing conditions and propose solutions for the critical areas. Variations of the models included existing and future development conditions and various storm events. The primary emphasis of the project was to evaluate the City’s major drainage systems on a regional level to determine channel and culvert improvements necessary to prevent flooding and the potential loss of life and property. Analysis for recommended improvements was based upon future development and a 25-year storm event. Several alternatives for each crossing were evaluated to determine the most cost effective solution.
From the models and recommended improvements, KSA was able to develop a Capital Improvements Plan for the City detailing the necessary improvements and preliminary construction estimates to implement the improvements. The various projects of the Capital Improvements Plan were then provided a priority ranking based on the elements of a priority matrix including projected project cost, benefit to City, and the effect the individual project would have on the overall drainage system.