IV-6-Surface Water and Groundwater Interaction along the River Yamuna in NCT, Delhi.

Abstract

Independently, the surface water and the groundwater systems have fairly been well understood but the interaction between surface water and groundwater is poorly understood. Improvements in understanding the interaction between surface water and groundwater may provide useful information about the impact on the environment and also for the better management of available fresh water resources. The present study has been carried out in Yamuna flood plain located in northern part of NCT Delhi which occupies an area of about 97 sq km. Number of tube wells has been constructed in the flood plains to withdraw water during non-monsoon months. The two main objectives of the study were (1) to understand impact of large scale pumping of groundwater in the floodplain of river Yamuna and (2) interaction of groundwater and river water in the Yamuna flood plain. In the present study, the isotope technique has been applied to understand the surface water and groundwater interaction between river Yamuna and adjoining groundwater in the Palla area of National Capital Territory of Delhi. Isotopic analysis (00 and aD) of the water samples indicates that the river Yamuna recharges the floodplain during monsoon season. The vertical recharge of the floodplain is more rapid and helps in build up of bank storage. Lateral recharge is slow as the hydraulic conductivity of the floodplain is 1-2 rn/day. River water contribution (lateral/vertical) in the pumped groundwater from the Yamuna floodplain varies from 20 to100% depending upon the intensity and duration of flooding in the monsoon season.