K. S. Jayappa

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.

Hypsometric analysis of Kali River Basin, Karnataka, India, using geographic information system

Hypsometric analysis is useful for understanding the geomorphic stages of a river basin. Hypsometric parameters have been evaluated and curves are prepared forall the 20 sub-basins of Kali River. Thirteen sub-basins are found to be under younger geomorphic stages with high hypsometric integral (Ea) values and subjected to recent tectonic activities. The remaining seven sub-basins are approaching mature stage and subjected to more erosion and less impacted by recent tectonic activities. Six sub-basins with lower hypsometric head values (<0.56) indicate least effect of diffusive processes and another six sub-basins with medium hypsometric head values (0.60–0.68) depict moderate diffusive erosion. The remaining eight sub-basins with higher hypsometric head values (>0.75) indicate highest diffusive processes at their upper reaches. Lower (<0.28) and higher (>0.44) hypsometric toe values indicate minimum and maximum mass accumulation respectively at the sub-catchment mouth.

Application of remote sensing and geographic information system in change detection of the Netravati and Gurpur river channels, Karnataka, India

The Netravati and Gurpur (N–G) river basins are tectonically active due to a number of seismically active faults/lineaments and their proximity to Mulki–Pulicat Lake axis. The gradient of the river channels has gradually reduced (after ∼10 km from their origin) and has forced the rivers to flow slowly in meandering and zigzag paths. The nature and intensity of meanders are governed by geological and tectonic conditions of the river basins. Significant changes in river channels, between the years 1910 and 2005, have been detected in three blocks – Block-I (Netravati) and Blocks-II and III (Gurpur) – and studied in detail by comparing topographic maps with Indian Remote Sensing Satellite, LISS-III images through GIS techniques. The block-wise qualitative and quantitative changes of these channels indicate that they are narrowed and migrate towards south due to neotectonic activities, formation of braided islands, variation in flow intensity and anthropogenic interventions like construction of vented dams and sand mining.

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.

Seasonal beach morphological changes along the coast of Udupi district, west coast of India

Spatial and temporal (pre- and post-monsoon) beach morphological changes along the Udupi district, Karnataka are investigated during 2011 and 2012. Beach profile surveys were carried out using traditional techniques at twelve selected beaches and estimated the cross sectional area and sediment volume changes. The data collected were computed and analysed using SANDS free software. Finally, based on beach profile changes, the inter-annual variabilities were quantified in-terms of cross-sectional area and sediment volumes. During the southwest monsoon period, width of the beaches in the study area reduced greatly and minimum volume of sediment is stored. The sediment volume was high during the post-monsoon season compared to the pre-monsoon season. Cross sectional area analysis reveals that most of the beaches in the study area accreted by >30%. However, the maximum reduction in areal extent at Mattu Katpadi, Gangolli, Maravanthe and Navunda beaches took place during the SW monsoon. Although cyclic in nature, large-scale erosion was found during SW monsoon but the lost sediment is regained in the post-monsoon period. Human interventions play a vital role in shoreline changes, in addition to natural processes.