A Development of a ‘ArcSWAT’ Surface Runoff Model for Estimating Urban Precipitation Recharge

Abstract

Groundwater recharge estimation is a fundamental part of groundwater resources management and may need to be estimated at a variety of spatial and temporal scales. Recharge is variable in time, responding to changes in land use and subsurface infrastructure as well as to climatic changes. Howevera, estimating recharge in urban environments is more complex than rural environments as it has many sources and pathways for recharge. Buildings, roads, land cover permeability, and other surface infrastructure combine with man-made drainage networks to influence recharge. Thus, this study is trying out an existing GIS-based system (ArcSWAT) to model and estimate urban recharge. The unconfined Triassic sandstone aquifer that underlies part of the city of Birmingham, United Kingdom (UK) was used as the study area for this project (occupies around 94.2km2 area). The results from this study show that SWAT model correlates better with 4RH (RMSE=17.78) as compared to UGif (RMSE=38.89) and 4ReH (RMSE=28.08). This is due to the reason that mains leakage factor has been included in 4RH and SWAT model. In summary, SWAT model produced a satisfactory result of urban precipitation recharge to the previous study that includes mains leakage factor during the modelling process.