Abstract:

Stormwater resources for groundwater recharge is one of the effective techniques to deduce and control negative environmental effects of groundwater overexploitation, but clogging problem of infiltration system is always the key restrict factor to broaden its practices. Based on the previous studies, the influence of D₅₀/d₅₀ ratio which indicated infiltration media size and suspended solid size on clogging layer distribution has been analyzed in the paper. As the aim to set up a predictive model to describe the surface clogging process, the urban stormwater had been adopted to recharge into fine quartz sand under a laboratory scale, and the observation data of hydraulic conductivity obtained by monitoring surface clogging process. According to the clogging generation conditions of the physical, chemical and biological, and the characteristics, it drew a conclusion that clogging property of this experiment belonged to physical clogging. Due to the clogging mechanism is as well as a membrane filtration, so cake filtration model was introduced to represent clogging development during the artificial recharge. The overall results manifested calculated data had a reasonably agreement with the observed outflow rate, and parameters α and f′R′ were determined as 0.15 m²/kg and 20 000 m/kg respectively. In order to verify the application of the model, different suspended solid sizes were simulated with model under the condition of parametersαand f′R′ kept constant, and the fitness were good. Hence, it is proved that the model could depict the real condition of surface clogging development when the ratio of infiltration media size to suspended solid size (D₅₀/d₅₀) less than 5, and it can be used to quantificational predict the clogging effect of recharge rate.

Key words: stormwater, groundwater recharge, suspended solid, clogging, hydraulic conductivity