Kumar Avinash

Prioritization of sub-basins based on geomorphology and morphometricanalysis using remote sensing and geographic informationsystem (GIS) techniques

Geomorphology and drainage characteristics of the Gurpur river basin have been studied using satellite images, topographic maps and geographic information system (GIS) techniques. Geomorphology and morphometric parameters have been used to prioritize the sub-basins (SB-I to -VII) and identify the most deficit/surplus zones of groundwater. The study reveals that 8% (SB-VII) to 85% (SB-II) area of the geomorphic units have poor to moderate groundwater prospect. About 16% (SB-V) to 92% (SB-VII) area were estimated as good to excellent zones for groundwater potential. Bifurcation ratio results show that geomorphic control predominates over structural control in the development of drainage network. Computed values of stream frequency of SB-II, SB-III and SB-VI indicate steep ground slopes, with less permeable rocks, while drainage density indicates that the river basin is moderately permeable. Sub-basin-wise prioritization reveals that SB-II is the most deficit zone, while SB-VII is found to be surplus zone of groundwater potential.

Basin geomorphology and drainage morphometry parameters used as indicators for groundwater prospect: Insight from geographical information system (GIS) technique

Influence of structural and lithological controls of various drainage patterns and their stream orientations (for 2nd, 3rd and 4th order steams) were identified to evaluate the direction and controlling factors of drainage network. To investigate the prospect of groundwater, hydrogeomorphological features of river basin viz. Mulki-Pavanje were identified and mapped. To evaluate the characteristics of the basin, different morphometric parameters (linear, areal and relief) were computed in sub-basin wise (SB-I to -VII). The linear parameters suggest drainage network is controlled by geomorphology. The form factor (Ff), elongation ratio (Re) and circularity ratio (Rc) suggest that the basin is in an elongated shape. The drainage density (Dd) indicates resistant/permeable strata under medium-dense vegetation with moderate relief. The areal parameters of the sub-basins (except SBI and III) indicates moderate ground-slopes associated with moderately permeable rocks, which promote moderate run-off and infiltration. Drainage texture (T) of the whole basin indicates coarse texture while the SB-I, and III showing an intermediate texture. The relief parameters namely ruggedness number (Rn) infers low basin relief and poor drainage density. To identify the most deficit/surplus zones of groundwater suitable weightages were assigned to the hydrogeomorphological units and morphometric parameters. The study reveal that the basin manifest that SB-III shall be most deficit zone of groundwater, whereas SB-VII, VI and V are found to show increase in groundwater potentiality. Groundwater prospect area in this basin is estimated to be 7% area under poor, 44% area under moderate and 49% area under good to excellent. This paper demonstrated the potential application of geographical information system (GIS) techniques to evaluate the groundwater prospect in absence of traditional groundwater monitoring data.