Trash Screens on Culverts in Urban Areas

Abstract

ABSTRACTThis PAPER DEALS with the performance of trash screens on culverts on urban watercourses. An assessment of the scope of problems associated with screens has been obtained from a survey of land drainage authorities in urban areas in England and Wales. The findings have been analysed and this has resulted in the development of four basic design criteria for screens. A detailed survey of the performance of some 17 sites in the river Ravensbourne catchment of the Thames Water Authority was undertaken over a number of years allowing relationships to be identified between debris amounts and types of upstream catchment area, screen/culvert area ratios, and priority of location.The paper describes considerations to be taken when providing a screen and advocates an individual design for each location rather than installing a standard arrangement. The lack of practical information in the UK, and the high level of problems experienced overall underlines the need for proper consideration to be given to this subject. Current research work is being undertaken to obtain preferred efficient screen configurations, but it is concluded that this should complement rather than replace the need for good trash screen design.