RURAL TO URBAN LAND TRANSFORMATION EFFECTS ON GROUND WATER LEVELS – A CASE STUDY OF GREATER NOIDA, GAUTHAM BUDH NAGAR DISTRICT, UTTAR PRADESHAshwani Kumar and S.M. Veerabhadrappa
Greater Noida evolved from 1991 with 101 villages to 2020 with 293 villages. This is an ideal case of rural to urban transformation in immediate past. This transformation led to decrease in recharging natural surfaces and increase in impermeable surfaces. Along with reduction in recharge areas, increase in population has necessitated more and more extraction of ground water resulting in an imbalance of water extraction and recharge. The result is depletion of ground water levels in this area. The area is part of the wide Indo Gangetic alluvium with sand, silt and clay layers resting of quartzites of Delhi Super Group. Geomorphology created using digital elevation models of the area shows older and younger alluvial plains and active flood plains of the river Hindon. Time series analysis of key land use land cover classes shows that recharge areas were reduced from 77% to 30% from 2005 to 2019 and impervious surfaces has increased from 19% to 65% for the same period of time. Aquifers of the area are of both phreatic and semi confined in nature. The aquifer parameters estimated through step drawdown test and long duration aquifer performance test indicates that average coefficient of transmissivity of the area is 1752 m2/day and average coefficient of storage is 4.84 x 10-4. Discharge of the wells shows a yield of 8 to 16 lps for a drawdown of 3 to 6m. An attempt has been made to know the behavior of ground water levels during same time period as that of land use land cover. The results indicate that 74% depletion in ground water levels with an average annual depletion of 21%. Interrelationship between urban growth and ground water levels has been established in this study. This analysis indicates that as agriculture declined water levels also depleted and have a positive correlation of 0.852. On the contrary, as built-up increased water level has depleted hence have a negative relationship with a correlation coefficient of -0.851. In order to make it a sustainable resource, this over exploited aquifers need careful participatory management by Community, Scientists, and policymakers.