Mapping and accuracy assessment of siltation of recharge dams using remote sensing technique

Abstract

this study demonstrates the use of ASteR data to map the siltation of the Al-Khod Dam constructed at the lower reaches of Samail catchment area, north Muscat, Sultanate of oman. in this study, the decorrelated image of spectral bands 6, 3, and 1 clearly discriminated the distribution of siltation. The occurrence of siltation is confirmed by the detection of minerals using the VNIR-SWIR bands by the Spectral Angle Mapper (SAM) method. in addition, the siltation of the dam is studied for the years 1987 to 2018 using Landsat satellite images. Interpretation of images showed a gradual increase of the siltation. Mapping accuracy for the occurrence of siltation is assessed by a confusion matrix which produced an overall accuracy of 97.88% and Kappa coefficient of 0.98 in the Maximum Likelihood method. Results of image analyses are verified in the field and confirmed through laboratory analyses. The study of spectral absorption characters of field samples using a Portable Infrared Mineral Analyzer (piMA) showed the presence of oH molecule bearing minerals (clays, serpentines, etc.) and carbonate minerals (calcite and dolomite) in the silt deposits. The occurrence of these minerals is confirmed further by X-ray diffraction (XRD) and Scanning Electron Microscope (SEM) analyses. Groundwater recharge in dams to increase the yield of groundwater for sustainability is very important in arid regions 1. Heavy rainfall and occurrence of flash floods in the regions may deposit large amounts of silts in the dams 2-7. The siltation is a major issue, hindering the infiltration of surface water into groundwater. Increase of such deposits reduce or stop groundwater recharge, decline groundwater levels, and well yields, and deteriorate water quality in and around the dam yearly 5,8. Researchers described the groundwater mounds beneath recharge sites 9-11 and infiltration during erratic floods in karstic basins 12-14. An in-depth study of alluvial stratigraphy provides detail about the number of timing, events, and deposited volumes of floods 15,16. A large number of check dams in the Mediterranean ephemeral streams have been built to prevent sediment inputs 17. Sedimentation rates are studied by infill stratigraphy of check dam and a model is proposed to evaluate erosion and sediment yield processes 18,19. However, meager attempts were made to study the siltations of the dams in Oman. Here the sedimentation in dams is influenced by numerous factors and the dams must be regularly cleaned and dried to continue the rates infiltration and storage capacities 4. In the Sultanate of Oman, many recharge dams across wadis were constructed by the government to hold up runoff and recharge the aquifers. But, most of the dams are silted now due to wadi flow after flash floods in catchments. A suitable technique to map and assess the silt deposits and sedimentation, an alternative to expensive and time-consuming methods 20,21 , is essential and urgently needed by scientists and engineers to remove or protect the deposits of the recharge dams. In thi...

Intra-annual sediment dynamic assessment in the Wei River Basin, China, using the AIC functional-structural connectivity index

“…As they play a critical role in (local) sediment yield reduction (Zhao et al, 2020;Feng et al, 2021), check-dams should be targeted as sinks when the location data is available and the pixel size of the DEM allows their representation as an input of AIC (González-Romero et al, 2021). Recent studies suggest that remote sensing can be introduced to assess the site of the check-dams (Rajendran et al, 2020;Guan et al, 2021). When calculating the index of connectivity (IC), which AIC was based on, originally a weighting factor was used to represent the ground cover and surface roughness that would obstruct water and sediment fluxes according to the characteristics of the study area.…”

Loss of Coastal Wetlands in Lake Burullus, Egypt: A GIS and Remote-Sensing Study

“…The confusion matrix (including user and producer accuracy presented in Table 2) and Kappa coefficient, which is a discrete multivariate parameter (Kappa statistic), were calculated to evaluate the performance and accuracy of the land-use classification for the satellite images [39,48,[54][55][56][57]. The accuracy indices range from 0 to 1, where a value of 1 represents a 100-percent land-use-classification accuracy.…”

Estimation of Sediments in Rengali Reservoir, Odisha (India) Using Remote Sensing

“…The sediment analysis and prediction of reservoir sedimentation is possible by soft computing like; ANN, SVM or GIS/RS, proved to be an effective tool used throughout the globe, [31,32,33,34,35]. Sedimentation and depletion of the storage capacity at FRL is common in Indian Reservoirs and utility in long run, [36,37,38,39,40]. The sedimentation of adjacent old reservoirs in the state comparable to Rengali have identical sediment concentration in the Hirakud reservoir in Mahanadi system [41].…”