Author(s): Le Song Ha; Chua Hock Chye Lloyd; Lo Yat-Man Edmond; Shuy Ban
Linked Author(s): Eng-Ban Shuy
Keywords: Stormwater quality; Landuse impacts; Tropical catchments
Abstract: To investigate the impacts of landuse on stormwater flow and quality, the concentrations and loads of11 water quality parameters (TN, TDN, NO x, NH 3 -N, TP, TDP, OP, SiO 2, TOC, DOC and TSS) and the relative contributions of flows from five sub-catchments of different landuse types (agricultural, forested and urbanized) were studied. High concentrations of nutrients (TN, TDN, NO x, NH 3, TP, TDP and OP) and TSS in both dry and wet weather flow from the catchment where agricultural landuse is prevalent highlights the impact of agricultural activities. For urbanized catchments, the impacts on stormwater are (1) stronger first flush effects, (2) larger part of rainfall volume appearing as direct runoff and less as subsurface flow (3) larger annual total runoff volume per unit area (4) higher contribution of runoff volume and loads from wet weather flow (WWF) than from dry weather flow (DWF). In addition, the study supports the correlation between loadings rates and degrees of urbanization. As landuse has significant impacts on stormwater flow and quality in the Kranji Reservoir catchment, further studies will target landuse-specific measurements on runoff quality to discretize the catchment model to a finer spatial scale. In addition, a hybrid distributed-lumped rainfall runoff model will be created to better represent the catchment.
Year: 2010