Groundwater quality modeling of Amaravathi river basin of Karur district, Tamil nadu, using visual Modflow

Abstract

Karur is the headquarters of Karur District in Tamil Nadu State. It is famous for manufacture of cotton cloths viz., bed spreads, towels and furnishings. This town is located on the bank of river Amaravathi which is a tributary of river Cauvery. At present 487 bleaching and dyeing units are in operation in this area. These units are located on either side of Amaravathi river. By average one unit generates 30 kilo litres per day (KLD) of wastewater from bleaching and dyeing process. For this research, Visual MODFLOW (2.8.1 version) software is used. Visual MODFLOW provides professional 3D groundwater flow and contaminant transport modeling using MODFLOW, MODPATH, MT3DMS modules. By considering the previous studies, the study area is limited to 40 Km x 8 Km. This 320 sq.km is divided into 8000 cells with grid size of 200 m x 200m with two layers. Top layer is unconfined aquifer and bottom layer is confined aquifer. The groundwater monitoring data for past 15 years, lithology, hydro geological parameters obtained from PWD, CGWB are given as input parameters to the model. Survey of India maps are used to assign the topography of top layer. Rail fall data from India Metrological Department are used. For this research purpose, 13 wells were identified in the study area and water quality and water level were monitored for three seasons. CETPs outlet quality was also monitored for one year on monthly basis. By using these data the MODFLOW and MT3D models were calibrated and validated. Renganathenpettai village is located near the confluence point of river Amaravathi with river Cauvery. Hence this area is not affected. Further other measures such as, ground water augmentation, scientific disposal of CETPs solid wastes, complete collection and treatment and disposal of Karur Municipal domestic sewage, proper maintenance of canals and the river, reducing of chemical fertilizers, banning of sand mining in Amaravathi river, cleaner technology by the textile dyeing units shall be under taken urgently.