Author(s)

M. Kamaka, E. Cheng, M. Teng & C. Matsuda

Abstract

Culverts are essential elements of a highway system. Currently, many hydraulic engineers are facing problems of sand-blockage inside culverts along coastal highways. To establish design criteria and a maintenance policy for Hawaii coastal highways, a research program is being carried out at the Department of Civil and Environmental Engineering, University of Hawaii at Manoa, USA. In establishing the design criteria for coastal culverts, we use overland flow theory to consider the design storm, drainage area, detention basin and culvert size as a system. A computational scheme is thus created. For predicting whether a sand-blocked culvert that may be opened by floodwater or it may need manual cleaning, we built hydraulic models for two existing culverts on the Island of Oahu, Hawaii in our Fluid Mechanics Laboratory. The preliminary results of our computer model and hydraulic model are very encouraging. Keywords: highway culverts, send-blockage, simulation model, direct runoff hydrograph, hydraulic model. 1 Introduction Coastal highway flooding or \“overtopping” by surface runoff is the concern. Mitigation measures considered herein are two-fold. The first management measure to minimize overtopping is attributed to the routine maintenance of a culvert, where the culvert is maintained free of debris to facilitate unimpeded surface runoff through a culvert. The second management measure is to assess the adequate nature of the existing culvert and detention pond combination as the

Keywords

highway culverts, send-blockage, simulation model, direct runoff hydrograph, hydraulic model.