3D Geological and Hydrogeological Modelling - Integrated Approaches in Urban Groundwater Management

摘要

Urbanisation has a major impact on groundwater recharge in both quality and quantity as well as groundwater flow beneath cities. The impact is due to the import of large quantities of water as well as the extensive use of the ground for effluent discharge, waste disposal and groundwater extraction. Hence, effective management of urban aquifers has to incorporate the negative effects on groundwater resources in the underlying groundwater systems. The effect on recharge arises both from modifications to the natural infiltration system and changes in natural drainage. These changes are induced by leakage from water mains and by wastewater seepage. The resultant effect on the quality of recharge is generally adverse with urbanisation processes being the main causes of severe, but essentially diffuses pollution of groundwater and rising levels of salinity. Widespread groundwater contamination results from chlorinated hydrocarbons and other organic compounds. Additional adverse effects on a more localised basis are due to pathogenic agents in upper aquifer systems with insufficient sewage and waste-disposal infrastructure. Changing groundwater related issues could affect urban buildings and infrastructure resulting from lowering of groundwater levels by high extraction rates for water supply as well as by rising water tables. The general change in water quality can create significant problems especially in the latter situation.