Research Article
Debasish Bagchi,
Abstract
Hydrogeological studies were undertaken in Garhwal Himalaya of Uttarkashi district; Uttarakhand to characterize the fractured; hard rock aquifer systems by inventorying cold-water springs; thermal spring and Key Observation Wells. Three major aquifer systems are identified in Bhagirathi valley along ChinyalisaurDunda-Uttarkashi-Bhatwari-Gangnani section. Spring discharge analysis has shown that spring magnitude and spring discharge variability are lowest in metavolcanics of Garhwal Group; whereas both of them are highest in slate-phyllite-quartzite aquifer system of Morar-Chakrata Formation. Anomalous seasonal discharge variation in selected springs indicates isolation of spring flow system from the atmosphere; which is correlated with regionally extensive thrust-fault system in Lesser and Central Himalaya. Long-term depth to water level analysis in Key Observation Wells indicate rise in water table in majority of the wells. This may be attributed to hydraulic connection between Bhagirathi River and the fractured rock aquifers and the rapid groundwater flow in interconnected fractures. The localized fractured rock aquifers are generally isolated from surface flow regime; which is indicated by absence of seasonal variability in groundwater levels upstream of Chinyalisaur-Dharasu area. Supply side aquifer management requires identification of sixth order springs that are most suitable for gravity supply through spring boxes at Ratodi Sar; Jestwari and Bagsari; among others. Groundwater recharge worthy areas are demarcated using multi-parameter analysis in ArcGIS; which shows that feasible sites for construction of mini tube wells are at Jaspur; Baldogi; Phari; Pipli Dhanari; Fold; Chakon; Dandagaon; Matli and in Uttarkashi-Gyansu-Mando section. Existing Water use efficiency needs to be increased by changing the cropping pattern and implementing participatory groundwater management at local and community level.