Landslide hazard assessment is an important step towards landslide hazard and risk management. There are several methods of Landslide Hazard Zonation (LHZ) viz. heuristic, semi quantitative, quantitative, probabilistic and multi-criteria decision making process. However, no one method is accepted universally for effective assessment of landslide hazards. In recent years, several attempts have been made to apply different methods of LHZ and to compare results in order to find the best suited model. This paper presents the review of researches on landslide hazard mapping published in recent years. The advanced multivariate techniques are proved to be effective in spatial prediction of landslides with high degree of accuracy. Physical process based models also perform well in LHZ mapping even in the areas with poor database. Multi-criteria decision making approach also play significant role in determining relative importance of landslide causative factors in slope instability process. Remote Sensing and Geographical Information System (GIS) are powerful tools to assess landslide hazards and are being used extensively in landslide researches since last decade. Aerial photographs and high resolution satellite data are useful in detection, mapping and monitoring landslide processes. GIS based LHZ models helps not only to map and monitor landslides but also to predict future slope failures. The advancements in Geo-spatial technologies have opened the doors for detailed and accurate assessment of landslide hazards.

In the present days, remote sensing and geographic information system (GIS) techniques are comprehensive tools for the assessment of water resource, its management and conservation. In this study, remote sensing and GIS techniques are taken into consideration for zonation of different groundwater prospects of Pravara basin. Several contributing factors in which groundwater potential of an area entirely or partially depends such as lithology, geomorphology, slope, soil, lineament density, drainage density, land use and rainfall are assessed individually as well as together for making the different groundwater prospect maps through influencing factor (IF) and frequency ratio (FR) techniques. In ArcGIS software, all these thematic layers are prepared using different satellite imageries and conventional data sets, obtained from different sources. All these layers are transformed into high-resolution raster format and meshed together in GIS environment using IF and FR methods. Groundwater prospect maps are constructed as a result of overlay analysis. Based on the constructed map of groundwater prospect zones, as a result of this study, the study area is divided into five categories of different groundwater potential zones: very high, high, moderate, low and very low. Validation of the resultant maps has shown that frequency ratio technique is having higher accuracy (AUC = 73%) compared to the influencing factors (AUC = 69%). The present study of groundwater zonation provides a simple and less time-consuming technique; also, the results can directly be used for planning and sustainable management in Pravara basin.

No abstract

Drainage network quantification with respect to the climate, tectonics, lithology and geomorphology provides significant evidence of the drainage development, hydro-geomorphic and denudation characteristics of an area. The present study was carried out by using Shuttle Radar Topographic Mission DEM to study the drainage morphometry and its influence on the hydrological characteristics of Vaitarna and Ulhas basins in Maharashtra, India. Results of the morphometric analysis reveal that the catchment of Vaitarna and Ulhas can be described as of 6th and 7th order drainage basins, encompassing an area of 3795 and 4733 km 2 , respectively. Additionally, Vaitarna basin is characterised by relatively higher mean bifurcation ratio as compared to the Ulhas basin, indicative of higher structural control and steeper gradient in Vaitarna basin. Lower drainage density and stream frequency affirm availability of permeable sub-surface material and homogeneous lithological characteristics in both basins. The shape parameters show both basins are semicircular with dendritic and sub-dendritic drainage pattern. The relief parameters of Vaitarna and Ulhas suggest both of these basins are characterised by very high relief and steep slope. GIS-based analysis of all these morphometric parameters indicates the drainage development of the study area progressed well beyond maturity stage and lithology have a major impact on the drainage development in Vaitarna and Ulhas basins.

No abstract