Spatio-temporal Variations in Groundwater Levels in Northwest India and Implications for Future Groundwater Management
Thursday, 18 December 2014
Northwest India is a global hotspot of groundwater depletion, with a mean rate of groundwater decline of ~4 cm/yr and regional depletion rates of ~20 Gt/yr as determined by 10 years of GRACE measurements (Rodell et. al. 2009, Chen et. al. 2014). This is one of the foremost agricultural regions of India with irrigation predominantly provided by groundwater extraction. However, satellite-based methods of groundwater-loss estimation are highly spatially averaged, and do not provide high-resolution spatial patterns of groundwater depletion. This limits the development of comprehensive groundwater management plans at micro levels. Here we resolve the spatial structure of groundwater loss in Punjab and Haryana states (NW India) through analysis of historical groundwater level data. We compiled state groundwater level observations from 2915 wells (1974-2010) together with Central Groundwater Board data from an additional 997 wells (2002- 2011) in the states of Punjab and Haryana. Parts of southern Haryana and southwest Punjab show dramatic decline in groundwater level by 12-18 meters during this period. The initial trend between 1974 and 1998 is much gentler compared to a steep decline between 1998 and 2010 as observed on time series plots. A few parts in western Haryana and southwest Punjab show rise in groundwater level varying from 10-18 meters during this period. The greatest decline in groundwater levels are observed within the Ghaggar basin, with a smaller area of extreme loss in southern Haryana. We estimate groundwater volume loss during 1974-2011 and compare this with variations in rainfall and groundwater abstraction during the period of 1974 to 2010.