Influence of Geological and Geomorphological Characteristics on Groundwater Occurrence in Deccan Basalt Hard Rock Area of Tawarja river Sub-Basin Latur, Maharashtra, India

The entire study area is covered by Deccan basalt formations comprising nearly horizontal lava flows of late Cretaceous to early Eocene. There are eight flows of lava found in the area and these flows have been considered to be a result of fissure type lava eruption. The types of basaltic flows occurring in the area are simple basalt (aa type) and vesicular-amygdaloidal (Compound pahoehoe type) basalt flow and also red bole beds (Tachylitic bands) are observed in the exposures, quarries and well sections. The drainage pattern varies from dendritic to sub-dendritic and sub-parallel. The bifurcation ratio is moderate (3.00 to 4.67) and the lower values of drainage density (1.77 km/km2) and stream frequency (1.74 streams/km2) indicates the region is of permeable subsoil strata of the basin. Morphometric attributes like form factor (0.85), circularity ratio (0.37) and elongation ratio (0.63) reflects the early mature stage of erosional development. The groundwater occurrence with reference to hydrogeological and geomorphological characters of the sub-basin is discussed. The groundwater occurrence is good productive in the geomorphic surfaces like moderately dissected plateau and pediplains, moderate in highly dissected plateau and lateritic uplands and poor in denudational hills.