Long-term groundwater recharge rates across India by in situ measurements

Abstract

Abstract. Groundwater recharge sustains groundwater discharge, including natural discharge through springs and base flow 15 to surface water as well as anthropogenic discharge through pumping wells. Here, for the first time, we compute long-term (1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014)(2015) groundwater recharge rates using data retrieved from several groundwater level monitoring locations across India (3.3 million km 2 area), the most groundwater-stressed region globally. Spatial variations in groundwater recharge rates (basin-wide mean: 17 to 960 mm/yr) were estimated in the 22 major river basins across India. The extensive plains of the Indus-Ganges-Brahmaputra (IGB) river basins are subjected to prevalence of comparatively higher recharge. This is mainly 20 attributed to occurrence of coarse sediments, higher rainfall, and intensive irrigation-linked groundwater abstraction inducing recharge by increasing available groundwater storage and return flows. Lower recharge rates (<200 mm/yr) in most of the central and southern study areas occur in cratonic, crystalline fractured aquifers. Estimated recharge rates have been compared favorably with field-scale recharge estimates (n= 52) based on tracer (tritium) injection tests. Results show precipitation rates are not significantly influencing groundwater recharge in most of the river basins across India, indicating 25 human influence in prevailing recharge rates. The spatial variability in recharge rates could provide critical input to policy makers to develop more sustainable groundwater management in India.

Using Satellite‐Based Vegetation Cover as Indicator of Groundwater Storage in Natural Vegetation Areas

“…The study area includes parts of India extending to an area of 3.29 × 10 6 km 2 . Annual mean precipitation in the study area exhibits distinct spatial variation, from extreme humid to arid climate, with the southwestern coast and some parts of the eastern India receiving very high amounts of precipitation (>250 cm/year) and the large parts of northwestern India receiving only <70 cm/year (Mukherjee et al, ) resulting to variable groundwater recharge pattern (Bhanja et al, ). Monthly mean ( n = 108) 0.25° × 0.25° gridded Tropical Rainfall Measuring Mission 3B43 precipitation data were obtained for 2005 to 2013 from the Tropical Rainfall Measuring Mission database (Kummerow, ).…”

“…Much of this huge population is largely groundwater dependent for their sustenance due to inconsistent rainfall patterns and the scarcity of clean surface water. Groundwater is mostly recharged by monsoonal rainfall (between June and September; Bhanja et al, ), which accounts for most (≥75%) of the annual rainfall over the study area (Guhathakurta & Rajeevan, ). A growing population will demand more agricultural output; hence, water resources that are already under pressure are likely to experience increased irrigational demand.…”

Is flood to drip irrigation a solution to groundwater depletion in the Indo-Gangetic plain?

“…Groundwater (GW) plays a crucial role in ensuring global water and food security. Besides direct withdrawals, it also contributes to baseflow to rivers during low rainfall conditions (Taylor et al 2013, Mukherjee et al 2018. Globally, India abstracts an enormous quantity of GW, utilizing nearly 90% of it to water almost 60% of irrigated land (CGWB 2021).…”

Economic and environmental impact assessment of sustainable future irrigation practices in the Indus Basin of Pakistan

“…The annual aquifer recharge (mm) is estimated from the Water Table Fluctuation method by adding the groundwater storage anomaly (mm) and the depth of pumped groundwater from the aquifer (mm) 69 , 70 . We use monthly terrestrial water storage data from the Gravity Recovery and Climate Experiment (GRACE) to estimate the groundwater storage anomaly.…”