Flow back-up caused by structures within open channels

• Main Author: Chen, Xingxia.
• Other Authors: Shuy Eng Ban
• Format: Final Year Project
• Language: English
• Published: 2009
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: http://hdl.handle.net/10356/15951
• Institution: Nanyang Technological University

With two-third of Singapore‟s total load area becoming water catchments, it is crucial to develop these utilitarian drains, canals and reservoirs beyond their functional use and transform them into vibrant, beautiful, clean and aesthetically pleasing lifestyle attractions where recreational and communal bonding activities can take place (Singapore‟s current ABC Waters programme). These developments will be done promptly through the construction of recreational deck ways that requires placement of supporting piers in the drains or reservoirs. Hence, this report aims to study the backwater resulted upstream of the bridge piers by three different methodologies namely energy, momentum and yarnell‟s equations. Simulation of pier configurations will be carried out using a hydraulic program, HEC-RAS, based on the number of piers used, the total channel blockage and the shapes of pier for each respective method. The energy approach has shown to be the most conservative method as it produces the largest flow backup for similar pier configurations. Also, the flow backup generally increases with an increase in the number of rows of piers across the channel with a square shaped pier causing the largest backwater effect followed by a triangular pier and a circular pier in decreasing order. It was observed for the same total channel blockage, the flow backup is independent of the lateral arrangement of piers across the cross section.