Description: Type H Inlets are frequently used by the Texas Department of Transportation as median drains for divided highways. Despite frequent use, engineers do not have adequate design information to mathematically describe the hydraulic performance of these structures. Typically, it has been assumed that IL-H-G and IL-H-L function essentially the same as roadway grates or curb inlets, but there is no basis for that assumption. Type-H drop inlets were investigated using a database from literature-reported experiments for similar inlets and physical model studies conducted at Texas Tech University (TTU). SWMM was investigated as a predictive tool by comparison to the TTU experimental results. The SWMM model was subject to very minimal calibration yet predicted performance reasonably well, especially when full inlet capture may occur. Examples of performance prediction using HEC-22, the power-law model and SWMM are presented to provide some guidance for Type-H inlet design.
Date: December 2010
Creator: Cleveland, Theodore G.; Rainwater, Kenneth A.; Smirnov, Sergey; Barnes, Wade; DaCosta, Larissa; Basnet, Bijay et al.
Item Type: Report