41.-Evalution of ground water quality in coastal city- A case study

Abstract

The coastal city of Kakinada is a part of river Godavari eastern delta system in Andhra Pradesh. The area under the study is around 85 km2 and it has the coast length of 8 kms along the Bay of Bengal. Total 164 groundwater samples were collected from 29 dug wells (Depth < 5mts) and 16 filter points (Depth 5 to 7 rnts.) during different seasons and analyzed fgr Temp. pH, EC and major anions (HCO3, Cl, SO4, PO4) and major cations (Ca, Mg, Na, K). The quality of groundwater is hard to very hard, but it is suitable for irrigation purposes. Based on SAR and %Na the study area falls under medium hazard of sodium. The comparison of water quality , parameters with ISI maximum permissible drinking water standards gives an indication that it is always better to tap groundwater through filter points in the study area, especially for drinking water purposes. The high value of SO4/C1 ratio indicates the impact of fertiliser use in the study area. The analysis of NO3 content in the month of November 99 (Well Nos. 1 to 29) confirms the high Nitrate content in the study area. The high Nitrate content is not only due to fertiliser use and it may be also due to high density of septic tanks in the town. The groundwater flow direction in the study area is towards saltcreek and Bay of Bengal.