Author(s): Ming Fai Chow, Siti Anieza Hasim, Clinton Paul Vun Phau, Najihasuhada Abi Jihat
Linked Author(s): Ming Fai Chow
Keywords: Event mean concentration, first flush, highway stormwater runoff, non-point source pollution, urban catchment.
Abstract: Highway stormwater runoff has been identified as the main contributor that deteriorates the receiving water quality. Many studies have been conducted throughout different countries to determine the relationship between highway runoff and its effects to the water bodies. This issue is important to Malaysia due to the rapid development of highways and increasing traffic volumes in recent years. Thus, the objectives of this study are to (i) determine the highway stormwater runoff quality; and to (ii) investigate the transport mechanisms of highway pollutants under different storm sizes. A total of three storm events have been monitored at the Kajang Silk Highway and 19 stormwater samples with 500 ml volume each were collected using manual grab technique. The stormwater flow rates were measured and water samples were collected during the rising and falling limbs of storm runoff. The stormwater samples were analyzed for COD, DO, pH, TSS and turbidity. The event mean concentration (EMC) and first flush effect were determined for each pollutant in every storm event. The results showed that the EMCs for COD, DO, pH, TSS and turbidity were 38. 5 mg/L, 9. 48 mg/L, 7. 9, 86. 4 mg/L and 33. 8 NTU, respectively. The highway runoff quality in this study was categorized as class III based on Department of Environment Malaysia's water quality index classification, which required extensive treatment for water supply. TSS and COD both showed strong first flush effects in this study. The results suggested that initial treatment is required to reduce the pollutant loadings in highway stormwater runoff