Detection and Assessment of the Waterlogging in the Dryland Drainage Basins Using Remote Sensing and GIS Techniques

Abstract

Waterlogging and elevated soil salinity commonly develop in the cultivated and arable areas of the Sahara, particularly within closed drainage basins. Multi-temporal remote sensing data of the Landsat Thematic Mapper (TM) and Enhanced Thematic Mapper (ETM+) for the Farafra Oasis in the Western Desert of Egypt were collected and processed to detect land cover changes, cultivations, and the extent of water ponding and seepage channels. The Shuttle Radar Topography Mission (SRTM) Digital Elevation Model (DEM) has been processed to delineate catchment morphometric parameters and to examine the spatial distribution of cultivated fields and their relation to the extracted drainage networks. The soil of these closed drainage basins is mainly shallow and lithic with high calcium carbonate content. Therefore the downward percolation of excess irrigation water is limited by the development of subsurface hardpan, which also saturates the upper layer of soil with water. The subsurface seepage from the newly cultivated areas in the Farafra Oasis has revealed the pattern of buried alluvial channels, which are waterlogged and outlined by the growth of diagnostic saline shrubs. Furthermore, the courses of these waterlogged channels are coinciding with their counterparts of the SRTM DEM, and the recent satellite images show that the surface playas in the downstream of these channels are partially occupied by water ponds. The geomorphology of closed drainage basins has to be considered when planning for new cultivation in dry land catchments to better control waterlogging hazard. Accordingly, several management strategies can be adopted to combat land degradation by water logging including; cultivation of certain areas and localities within each drainage basins, and conveying the drainage and seepage water through the inactive alluvial channels into abandoned playas, which are reserved for evaporation. Moreover, farm management and balancing irrigation water, salt leaching, and evapo-transpiration are also critical to lessen the development of waterlogging.

Regional watershed characterization and classification with river network analyses

“…neglecting groundwater flow impacts and assuming a continuous spatial autocorrelation of river network properties). Secondly, other geomorphologic indices could have been used for the same objective (El Bastawesy et al , ). Furthermore, we need to take into account the spatial autocorrelation observed between close watersheds, probably due to substrates and precipitation fields continuous in space.…”

“…The geomorphologic properties of watersheds condition the use of fresh water upon which human and natural ecosystems depend for their sustenance. Although many factors may constrain water fluxes, the pattern responsible for most of the flow availability should be accurately quantified (Rodriguez‐Iturbe and Rinaldo, ; Olden and Poff, ; Cudennec and Fouad, ; El Bastawesy et al , ); this step becomes even more difficult when hydrological systems are poorly gauged (El Bastawesy et al , ; Blöschl et al , ; Hrachowitz et al , ). To analyse flow paths is critical in developing countries such as Haiti, where a large population depends on the water resource, either for its drinking needs, for food production or for flood and erosion mitigation (Frelat et al , ; Shamir et al , ).…”

“…In a sense, this characterization stage intends to capture most of the geomorphologic drivers of the water fluxes through the watershed. Volumetric and surface indices are the most commonly used and are often computed on the basis of digital terrain models (DTMs) and land cover maps (Sawicz et al , ; El Bastawesy et al , ). We will use them here, among a wide range of remote sensing and other spatial data such as land cover, flooding area and geological (fault) maps.…”

Rain Water Harvesting Using GIS and RS for Agriculture Development in Northern Western Coast, Egypt

“…DEM was employed to offer varieties of data that assist in produced landforms map, soil types and hydrology information. Drainage networks and sub-catchment boundary of the studied areas were extracting from DEM in order to investigate the spatial relationship of agriculture fields and the catchment-drainage networks [17].…”

“…lined with cement. The stored water inside these cisterns can be used for human and animal consumption and in some cases for irrigate the young tress [17].…”