Water cycle impacts of residential water demand in an aquifer-based municipal water supply and treatment system: Model development, implementation, and case studies

Abstract

The hydrological cycle is significantly impacted when natural land cover is converted to urban land use. Pristine land cover and urban development have very different infiltration, evapotranspiration, and runo ff rates, affecting streams and groundwater recharge. Rapid urbanization globally has resulted in the transformation and modification of natural land cover such as forested and grassland to industrial, commercial and residential developments. In addition, urban areas are served by potable and waste water systems that supply, treat, and convey water from source water through infrastructure to treatment and disposition. Shifting water partitioning through impervious surface change and the introduction and mobilization of water into urban environments alters the water cycle, affects streams and aquifers, and impacts ecological systems. The research has developed a water balance model framework to analyze the effect of the built environment on water partitioning and the consequential impact on the environment. Results from the application of the water balance model on two communities in Alachua county, Florida indicated that hydrological factors such as infiltration and runoff increase significantly when land is transformed from an undeveloped to a developed state with increased imperviousness. Also affected are water withdrawal volumes, irrigation water use, and how extracted water is treated and disposed. Approximately 50% of the difference between undeveloped and developed conditions were alleviated with the use of effective stormwater management practices. The study concluded that significant changes are observed when land is altered from its natural state and measures to maintain natural land cover water flow characteristics in urban areas are necessary to control this change.