STATEMENT OF THE PROJECT

Between 25% and 50% of the cost of most highway projects is attributable to drainage facilities, such as storm drains, highway culverts, bridges, and water quality and quantity control structures. Design of these facilities involves a hydrologic analysis to determine the design discharge, and a hydraulic analysis of the conveyance capacity of the facility during which the water surface elevation and flow velocity are determined. The goal of this research project is to reduce the cost and improve the accuracy of the design of drainage facilities by integrating hydrologic and hydraulic design procedures with spatial data describing the stream channel and watershed.

The Texas Department of Transportation (TxDOT) has existing procedures for hydrologic and hydraulic analysis in the Texas Hydraulic System (THYSYS) but each application requires the computerization of the description of the watershed and the stream channel using data extracted mannually from maps and cross-sections contained in paper drawings. By building a spatial database of hydrologic and hydraulic data for Texas, and developing design procedures which operate off this database, a significant saving in time and improvement in accuracy of design procedures is possible. Additionally, the separate hydrologic and hydraulic aspects of the design can be closely integrated using a spatial model of the design site by automatically transferring design discharges determined in the hydrologic analysis and making them inputs to the hydraulic design.