Maharashtra Shows Why Recharge Suitability Is Not the Same as Groundwater Potential

Groundwater planning in Maharashtra’s Deccan basalt can change sharply depending on the question being mapped. In the Moha-Karewadi area of Beed district, only about 2.07% of the mapped landscape falls in the very-high groundwater-potential class, while about 8.86% is rated very high for recharge suitability. The contrast shows why a site that accepts water efficiently at the surface is not automatically the best place for a high-yielding well, and why groundwater development and recharge planning require different geological evidence.

The local aquifer is controlled by the layered character of basalt. Weathered and fractured basalt near water-harvesting structures occurs at roughly 7–10 m depth in the investigated locations, providing pathways through which infiltrating water can move. Compact basalt beneath or beside these zones can sharply reduce deeper percolation. Productive groundwater may therefore depend on the thickness and connectivity of weathered zones, fractures, flow contacts and local structural features rather than on surface infiltration alone.

Eight electrical soundings, infiltration measurements and GIS layers were used to build the interpretation. Each method answers a different part of the problem. GIS provides a regional screening framework, infiltration tests describe how rapidly water can enter the near-surface material at selected points, and electrical resistivity helps distinguish subsurface layers and possible weathered or fractured zones. None of these measurements by itself proves long-term aquifer yield.

The distinction can be stated simply. Recharge describes water entering the ground. Storage describes how much water an aquifer can hold. Transmissivity describes how readily that water can move through the aquifer. A highly permeable surface may allow recharge but overlie compact rock with limited storage, while a productive fracture zone may lie away from the best surface infiltration area. Treating a recharge-suitability map as a borewell-success map can therefore lead to poor siting decisions.

A defensible project sequence is to use GIS to narrow the search area, infiltration testing to characterise surface behaviour, resistivity to investigate subsurface structure, and then wells, water-level monitoring and hydraulic tests to confirm aquifer performance. The 2.07% versus 8.86% contrast is valuable because it converts a common conceptual mistake into a measurable planning lesson: the map must match the decision before construction begins.