Runoff quality modelling for urban catchments

• Main Author: Du, Wei Bing.
• Other Authors: Chua Hock Chye Lloyd
• Format: Final Year Project
• Language: English
• Published: 2010
• Subjects: DRNTU::Engineering::Civil engineering::Water resources
• Online Access: http://hdl.handle.net/10356/38555
• Institution: Nanyang Technological University

Land use studies were conducted for both Kranji and Marina catchments. SWMM was then used to simulate the quantity and quality of urban storm water runoff from KC02 catchment in Kranji. Modelling works for the Marina catchment but would not be carried out due to lack of data. A total of 12 storm events were used to calibrate and verify the model for KC02. A total of 8 water quality parameters: total suspended solids (TSS), total nitrogen (TN), total phosphorus (TP), ammonium (NH4), total organic carbon (TOC), ammonia + ammonium (NO2+NO3), ortho-phosphate (OP) and silica dioxide (SiO2) were modelled. The event mean concentration (EMC) and rating curve (RC) methods were used to simulate the water quality parameters and an initial analysis of the exponential build up and washoff functions were performed. EMC produced a higher median load of up to 50% from the measured load for all parameters with the exception of TP and SiO2. The reason that the water quality parameters has been over estimated is due to the higher flow simulated from the verification process which affects the total load. TP and SiO2 has a median of 14% to 17% which indicates that the EMC method is reasonably accurate to model for these parameters. RC analysis parameters have also been over estimated in the range of 30% to 60% with the exception for TP with a median of 8%. TP and %. SiO2 has a smaller spread of simulated results.