Effect of urban developments on ground water regime

Abstract

In most cities, water quantity and water quality depreciation are found to be the major issues that affect the environment. Due to urbanization and growth of population, water becomes the vital property which has to be guarded safe for our future growth. Hence, any development has to be done with a cautious eye on this precious source. This research focuses on the impact of urban development strategies, particularly the construction of underground Metro rail corridors in the heart of Chennai City, on the availability of water, i.e., water quantity as well as the water quality. The construction of Metro rail corridor involving lots of pumping of water and the tunneling work affects the ground water aquifers. The change of the heterogeneous soil strata affects the water quality too. An attempt has been made to study the water availability both quantity and quality in the study area and to arrive at a holistic solution. The study aims to evaluate the environmental pollution associated with water quality parameters into the groundwater, using contaminant transport model. The work extends to study the changes in the ground water levels due to the obstruction created in the name of tunnel below the surface level as a barrier in the soil strata. To understand the variations in the groundwater levels and water quality, spatial and temporal analysis has been done using the premonsoon and post monsoon water levels and with the water quality parameters. The comparison has been done in three phases before, during and after construction. 20 wells are identified opposite to the construction of Underground metro rail corridors on either side 5 wells each. Levels are monitored and the samples are taken for quality analysis to study the effect of tunneling on either side of the corridor. Using water table fluctuation method, the storage of the aquifer was identified for before and after the construction. In MODFLOW, this is identified and the storage is identified with the massbalance for different time steps. Groundwater flow va