Hydraulic facilities include open channels, bridges, culverts, storm drains, pump stations, and storm-water quantity and quality control systems. Each can be part of a larger facility that drains water. In analyzing or designing drainage facilities, your investment of time, expense, concentration, and task completeness should be influenced by the relative importance of the facility. This manual provides procedures recommended by the Texas Department of Transportation (TxDOT) for analyzing and designing effective highway drainage facilities.