ASSESSMENT OF SUSTAINABLE GROUNDWATER RESOURCES OF THE INTERBASIN AREA OF BETBAN-RAO AND DHAULNA.RAO RIVERS, DIST.: HARIDWAR (UTTRAKHAND)

Abstract

An integrated approach of geomorphological. geohydrological, geoclectrical. and GEC (1997) recommendations have been used to estimate groundwater potential in the piedmont zone of I IimaIayan foothill region of District 1-laridwar, tJttarakhand, India. Various sustainability parameters like Deforestation Rate (Land use parameter), Water Barrier Index (per capita water requirement) and Integrated Water Stress Score (water quality indicator) has been also estimated lr long time water sustainability evaluation in the study area. The study area is situated between Latitude 29°58'0" North to 30060 North and Longitude 77°59'30' East to 78°5'30" East falling in Ratmau-Rao watershed. The study area is approximately 42.24Km2. Ilydogeomorphologically. the piedmont deposits of the study area are divided into Bhabhar and Terai zones.The l3habhar is a steeply sloping relatively dry tract made up of assorted sediments brought down by rivers emerging from Siwalik hills. Geologically, the Bhahhar was formed in the recent era by integration of piedmont of alluvial fan deposits consisting of unconsolidated sand. boulders and clays. The larai zone occurs immediately below Bhahhar and is composed of alternation ol'sand and clays, at places impregnated by calcareous nodules commonly reièrred as Kankar. Systematic studies have been conducted in the present work to develop the methodology for the groundwater evaluation in the study area. Hydrogeomorphological investigations have been carried out using remote sensing and GIS techniques to have a preliminary assessment of the groundwater resources in the study area. Various thematic maps have been prepared for, slope, and landuse. Shallow and deeper aquifers are generally present in the area separated by clay lenses. In the l3habliar zone the shallow aquifer consists ol'admixtures of sand and gravel of varying sizes. In the 13habhar zone, the clay is often impregnated by kankar. The previous study by 1-ladithi (2004) shows that the depth of water table in the i'anda village situated near the southern periphery of the Ar 46 lv 4- study area was 8 in below ground level (bgl) during premonsoon period of 2003. Groundwater V level was 7.2 in bgl after the monsoon season of the same year. The seasonal water table fluctuation in the area as deciphered in a dug well located in Tanda village was of the order of I .12 ni (I ladithi, 2004). In the present field study. the depth to water table was recorded as 8.20 m bgl in a dug well inventoried in Aurangabad village. Two soundings were recorded by using Schlurnherger electrode configuration with the maximum current electrode separation of 700 in. The values of apparent resistivities obtained in the field were plotted against half current separation (AB/2) on a log- log paper and the graphs were interpreted. The interpretation of the curves has indicated presence of an unsaturated dry lrmation unto the depth of 15 in bgl (with resistivity of 260 mm at yES-I). 'l'his zone is composed of coarse assortment of sand-gravel which gets coarser in nature towards northeast (at yES-Il ) as indicated by the increasing true resistivity (of the order of 1400 ohm in). This dry zone is underlain by an aquifer having resistivity of 52 to 198 ohm m which has the thickness varying from 57 in in the south at (yES-I) to over 100 in (at yES-Il ) towards northeastern forest. It is reported that the current depth of groundwater in the Yog-Gram tube well (no. 1) is around 33 in bgl. Groundwater recharge is estimated using rainfall infiltration factor method and water table fluctuation method as per method of GEC (1997). The present study shows that Net groundwater availability for the whole year in the study area is 831.74 ha-ma and stage of groundwater development is 38.59% which is categorised as Safe. For evaluation of sustainability parameters, deforestation rate for period of 2000 to 2013 has been calculated using Earth Resources Data and Analysis System (ERDAS) IMAGINE which comes out as 0.828% and is not considered alarming. The estimation of Water Barrier Index V. (WBI) have put the study area and its suburbs in No Stress' category whereas by Integrated Water V Stress Score (IWSS) approach also the study area is categorised as 'moderately' to 'highly stressed'. It is found that groundwater resources development in the study area and its suburb is sustainable.