Groundwater modeling and demarcation of groundwater protection zones for Tirupur Basin – A case study

Groundwater is a renewable resource and has to be protected from contamination. The concept of a zone of protection for areas containing groundwater has been developed and adopted in a number of countries. One such area is Tirupur, (Tamil Nadu, India) which is an arid region and rapid expansion of the textile industry has taken place with no associated development of supporting infrastructure or institutional capacity. Textile production, particularly dyeing and bleaching is water intensive and generates large quantities of effluent. One of the most significant challenges for the Tirupur textile industry today is water for bleaching and disposal of effluent. Demarcation of groundwater protection zones has become necessary to facilitate recharging of the aquifer to meet the water demand. These zones are considered sensitive zones and should be free from activities such as the groundwater over exploitation, effluent discharge and construction of barriers. Groundwater flow for Tirupur Block was simulated using visual MODFLOW version 4.1. The model was run for the year 1998–99 with transient flow condition. Taking June 1998 water level as initial head, the model was run to simulate water level up to May 1999 and validated with the observed data for all the six wells which are distributed over six different zones. The results obtained from the simulation were used to assign the ranks and weights for overlay process in Geomedia environment. The consequent higher index values indicate the sensitivity zone influencing recharge to the aquifer which should be demarcated as groundwater protection zones. This groundwater protection zone will be designated as pollution free zone for better management of the aquife.