Studying Rain Water Catchment Potentialities in the Northwest Coast of Egypt Using Remote Sensing and Geographic Information System

Abstract

Sustainable agricultural development of the desert areas of Egypt under the scarcity of irrigation water is a significant national challenge. Existing water harvesting techniques on the northwest coast of Egypt do not ensure the optimal use of rainfall for agricultural purposes. Basin-scale hydrology potentialities were studied to investigate how available annual rainfall could be used in agriculture irrigation to increase crop production. The present study includes data related to agricultural production in the form of geospatial layers including climate, soil, land covers unite and rain water catchment areas. Thematic classification of Sentinal-2 imagery was carried out to produce the land cover and crop maps following based on the (FAO) system of land cover classification. Contour lines and spot height points were used to create a digital elevation model (DEM). Then, DEM was used to delineate basins, sub-basins, and water outlet points using the Soil and Water Assessment Tool (Arc SWAT). Main soil mapping units of the study area identified from Land Master Plan maps it was(Very shallow gravelly and rocky soils and barren rock). Climatic data collected from the Central Laboratory for Climate. The results showed that the study area receives a significant amount of precipitation almost every three years, however, water harvesting methods are inappropriate to store water to be used in agricultural during drought seasons. The amount of precipitation(81.9 mm), surface water runoff(4.46 mm), potential evapotranspiration(70.5 mm), and actual evapotranspiration(7.10 mm) for the years (2004 to 2017) shown as results of (Arc SWAT). The land cover map showed that tree crops (olive and fig) cover 195.8 km2 when herbaceous crops (barley and wheat) cover 154 km2. The maximum elevation was 250 meters above sea level while the lowest one was -3 meters below sea level. The study area receives a massive variable amount of precipitation; however, water harvesting methods are inappropriate to store water for purposes.