Delineation and mapping of palaeochannels using remote sensing, geophysical, and sedimentological techniques: A comprehensive approach

Abstract

Palaeochannels are remnants of rivers or stream channels that flowed in the past and have been currently filled or buried by younger fluviatile sediments. There are a number of techniques for detecting palaeochannels with each of them having its own intrinsic advantages and disadvantages. In the present study, apart from applying different approaches, the capabilities, and effectiveness of the approaches to locate and map palaeochannels are compared. Remote sensing-based approaches are comprised of high-resolution satellite datasets and a LiDARderived elevation map for displaying extensive drainage networks of surface feature channels hypothesized to be palaeochannels, palaeorivers, or palaeovalleys. Ground-penetrating radar (GPR) transects along with concurrent visual observations are ground-truthing field approaches and has proved to be one of the most appropriate and accurate methods for locating palaeochannels due to their capability to identify subsurface sedimentary stratigraphy innate to palaeochannels. Nevertheless, visual field observations for ground-truthing of prospective palaeochnnels either exhibiting only subtle alterations in desiccation or vegetation are considered a potent field approach. The present review work lays a strong emphasis on delineation and mapping of palaeochannels using remote sensing, geophysical, and sedimentological techniques to meet the sustainable groundwater development goals.

Spatial Distribution of Landslide Susceptibility in New Road Construction Mengwitani-Singaraja, Bali-Indonesia: Based on Geospatial Data

“…An analysis of the landform digitally using the Alos Palsar DEM comparison with the vegetation index from Sentinel 2B imagery with a spatial resolution of 10 m [18]. This research is interpreted visually so that the interpretation is by the actual condition of the land cover object and topography [24]. The landform that spans the area is a volcanic downslope covering 11,578.95 ha (28.85%) of the total area of the study site.…”

“…Based on the results of the extraction of the Digital Terrain Model of Alos Palsar Acquisition in 2011, the study area is classified into five classes of the slope, which are presented in fig 2e. Also, Palsar DEM is good for use in slope analysis because the height value in Alos Palsar DEM is the actual topographical height of the soil [24] without a canopy on it ( Digital Terrain Model ). The slope class with the 15-30% category dominates the research area covering an area of 9,119.38 ha (22.73%).…”

“…On the other hand, disaster risk mapping for each region has also been required in the RI Law no. 24 (1) identify the factors that most influences landslides susceptibility along the new road section (Mengwitani-Singaraja) Bali Province, (2) the spatial distribution of landslide hazards along the new road section, and (3) identify the relationship between landslide susceptibility and previous events based on field information and secondary data information.…”

Mapping and evaluating the condition of artificial levees

“…Several GPR profiles taken on the levee foot correspond with Ritambhara et al (2021) revealed the presence of paleo-river channels, and a unique reflector feature explained the old banks and the younger sediments that filled these channels. Because it might result in the growth of sand boils on the levee's protected side, , thus increasing flood risk (Nagy, 2000;Ojha et al, 2001;Tímár, 2020).…”