NIH/AR/14-15 : IWRM Studies: Surface water and groundwater interaction in Y drain of Lower Errakalva basin

Abstract

To understand the interaction of surface water and groundwater it is important to know the mixing of various sources of water like precipitation or evaporated or storage water bodies and releases from them or recharge to aquifers to understand the man’s influence on streams and aquifers. It can help plan or prevent deterioration of water quality by salinization and pollution. The environmental isotopic methods provide a valuable approach to understand the complex phenomena of rainfall - surface water - groundwater interactions. The application of the environmental isotope methods to understand the origin of sources of surface and groundwater with respect to its recharge is based on the spatial and temporal variability of the isotopic contents of water. Errakalva river drains West Godavari district for about 180 km and joins the Upputeru river, which takes off from the Kolleru lake falls into Bay of Bengal. Errakalva enters the Godavari western delta, after draining an area of including that of upstream catchment of 2330.10 km2, near Nandamuru aqueduct of Tadepalligudem Mandal and emerges as Yenamadarru drain and debauches in to Bay of Bengal through Upputeru major creek. In this study, as part of IWRM project in Errakalva Pilot basin, variation of measurement of stable isotopes of Deuterium and Oxygen i.e,  D and  18O in the water samples of precipitation, canal water, stream water, tank water and groundwater collected in the Yanamadurru drain, discharging from 394.93 km2 in deltaic plain is studied and analysed. The variation of stable isotope 18O16 in the surface and ground waters of the lower part of Errakalva basin called Yanamadurru drain or Y Drain system is discussed to understand the proportion of mixing of sources waters in surface water and groundwater at different locations.