RN-1 : Hydrogeological investigations of the Ganga Hindon inter basin - Upper Ganga canal command area

Abstract

The command of Upper Ganga Canal (UGC) system covers an area of about 24,500 sq.km. located between the rivers Ganga and Yamuna and forms a part of the Gangetic alluvial plain. The area is characterised by tropical climate with mean annual rainfall of the order of 900 mm. The temperature varies between 47 to 2 degree centigrade respectively in summer and winter. The area is characterised by gentle slope towards south and south-east directions. Recent alluvium is the major geological formation occurring in the area.

The aim of the present study is to have an integrated picture about the present hydrogeological conditions in the area, particularly, evaluation of aquifer characteristics through pump test, delineation of recharge and discharge sites of groundwater, depth and fluctuation of water levels, type, nature and extent of water bearing formations, groundwater flow directions, gradients etc.

From the analysis and interpretations of the available data, it is seen that the utilisable groundwater in UGC area occurs mainly in alluvial parts. However, groundwater occurs in Bhabar and Tarai formations but is not extensively used either because of deep water levels or because of high costs of exploitations. Both confined and unconfined conditions prevail. The groundwater regime is recharged mainly through precipitation, seepage from canals and rivers and partly return flow from irrigation. The gentle gradients of the water levels indicate highly permeable formations in the area.

The water bearing formations mainly consists of sands of varying grain size, quite often mixed with clay and kankar. Clay layers are common and become increasingly predominant towards southern parts of the doab. Study of sand percentage distribution indicates two different depositional trends. The maximum sand percentage is found to occur in the northern parts of the area. Depth to water level varies considerably from place to place with maximum depth in highly permeable Bhabar zone. The artesian conditions exist along the contact zone of Bhabar and Tarai formations. Generally the fluctuation of water level is less than four metres in the major portion of the area. Groundwater mainly Flows in the south and south-east directions. River Ganga and Yamuna act as influent rivers in the upstream locations and become effluent in the downstream of the doab. The canal network has significant effect on the groundwater regime in the area. In general two aquifer layers can be delineated one at depth less than 35 m and other at depth greater than 35 m from ground surface. Deeper layers show leaky confined to confined character.

The chemical quality of groundwater is found to be good for drinking and irrigational purposes in most parts of the study area, except in south and south-eastern portions where the salinity is slightly above the upper acceptable limits for drinking and irrigational use.