The state of Gujarat is located in an arid to semi-arid area in western India. Throughout history, the state has witnessed several famines and droughts. At the present time, the region continues to be subjected to water stress due to high inter and intra annual rainfall variability, further exacerbated by climate change and population growth. As a result, groundwater represents a vital resource for drinking, domestic and especially irrigation supply. In fact, it accounts for almost 80% of the total irrigation demand in the state.
Due to the rapid agricultural development over the last decades, the region has been subjected to groundwater overexploitation. In order to cope with the unsustainable use of groundwater, the government implemented new energy policies to rationalise abstractions and promoted decentralised water harvesting structures to recharge the aquifers.
Many studies have reported a significant rejuvenation of the water levels with a reversal in the declining trends of groundwater storage in the last decade. However, there is still a lack of scientific evidence regarding the cause of this rejuvenation. Multiple possible drivers have been proposed, including: the change in rainfall patterns, the introduction of new energy policies by the government, the import of surface water from the Sardar Sarovar dam and the widespread implementation of rainwater harvesting structures for MAR.
The aim of this study is therefore to thoroughly assess the impact of widespread MAR on groundwater resources. This was done by combining local and catchment scale assessments of MAR impacts through a multi-scale analysis. The study area chosen for this analysis is the Bhadar basin (6 500 km2), located in the southwestern part of the Saurashtra peninsula in Gujarat. This area is characterised by hard rock aquifers and has witnessed the strongest development of MAR structure among the state, with more than 4 000 check dams only in Bhadar basin. Because of the fore-mentioned discussion over Gujarat aquifers' replenishment, and the scale and intensity of MAR implementation, this region offers a unique opportunity to assess the large-scale impact of this technique.
In this part of the study, the focus is on the local scale MAR structure impacts. This entails the systematic analysis of 3 representative MAR structures in terms of recharge capacity, availability of water recharged underground for its subsequent use, water balance of structures, and dynamics of water demand, in terms of irrigation practices, crop patterns and calendars. A MAR typology is then used to upscale to the basin scale applying local findings.