Updating Culvert and Storm Drain Design and Installation Methods
Author: Amanda L. Cox (University of Saint Louis)
A research program was conducted to evaluate the performance of two Colorado Department of Transportation (CDOT) highway median storm drain inlets, Type C and Type D. Inlets tested are currently used by both the Urban Drainage and Flood Control District (UDFCD) of Denver and CDOT. Theoretical flow depth-capacity curves have been developed for the Type C and D inlets, but were not previously laboratory tested. Current design practices are based upon general application of the orifice and/or weir equations. A 3:1 Froude-scale model of a highway median was designed and built to provide data to evaluate the accuracy of the existing rating equations. The model consisted of a constructed highway median channel with one interchangeable inlet. Six types of inlet configurations were tested: on-grade and depressed inlets for Type C, Type D and Type D rotated. A total of 120 hydraulic tests including twenty-four debris tests were performed. Variations in grate angle measured along the slope (0, 10, 20 and 30 degrees) were investigated to provide flow-depth and discharge data for each inlet configuration. Evaluated prototype flow depths ranged from 0.3 to 0.9 m. Resulting stage-discharge data were tabulated and plotted, and qualitative observations were made regarding the hydraulic conditions during testing and debris assessments. Stage-discharge data for the grate inlets were compared to existing methods for computing inlet efficiency, and a new rating equation was developed for median inlets with orifice flow.
Keywords:
How to Cite: Cox, A. L. (2014) “Hydraulic Efficiencies for Colorado Department of Transportation Type C and D Median Inlets”, National Hydraulic Engineering Conference 2014. 1(2014).