Bioretention system is one of the best management practices for rainwater runoff redirecting and storing before discharge into existing stormwater system. On the other hand, road divider is designed for dividing the traffic flow for road safety. However, it may be a blockage for surface runoff on road and possibly created ponding during heavy rainfall event. This scenario could become a hazard for motorised vehicles. In this study, a grassed road divider in Broga Road, Semenyih, Malaysia, is modelled as bioretention system by EPA's Storm Water Management Model (SWMM) to investigate the performance of its application. A case of grassed road divider without bioretention cell was also modelled for comparison. A series of simulations were carried out for the ARI of 2, 5, and 10 years to further study the performance of grassed road divider as a bioretention system. Four different types of soil including sand, loamy sand, loam, and sandy loam are selected as filler soil in the bioretention cell. Results from the model simulations showed that the performances of grassed road divider as a bioretention system can reduce the surface runoff into the stormwater system up to 49.9% and 56.77% for different ARIs. The effect of this implication is more significant on the reduction as the ARI increased. Results also showed that the impact of soil types is insignificant. The findings show that a bioretention system in a grassed road divider may supplement conventional urban road drainage and provide an effective stormwater management.

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Conventional urban drainage structures that store water over time are habitat for the mosquito larvae. Appropriate stormwater management practices can help in preventing the breeding of the mosquito larvae. Thus, a study was conducted to evaluate the performance of a proposed bioretention system in controlling dengue at the campus university in Semenyih, Malaysia. The XP Stormwater Management Model (XPSWMM) was applied for the numerical analysis and modelling in this study. A series of simulations were carried out for the ARI of 2, 5, and 10 years to evaluate the performance under the two scenarios of conventional drainage system and bioretention system, taking into considerations the maximum water depth (stages), inflow volume from runoff, and pollutant load reduction from the sub-catchments to control the breeding of aedes mosquitoes. The simulated results indicated that the bioretention system is capable of reducing the maximum water depth (stages) of the sub-catchments to up to 85% as compared to the conventional drainage system. In addition, the reduction of the inflow volume from runoff ranges from 0.3% to 0.5% and the pollutant loads reduced by approximately 100%. The reduction in water depth and inflow volume will result in mitigating the risk of water stagnancy within all the sub-catchments of the study area. The simulated results demonstrated that bioretention system could be used effectively to control the breeding of mosquitoes. Hence, the findings obtained in this study can assist the decision makers of the university in the adoption of bioretention system to control dengue within the campus.