Shuttle Radar Topography Mission (SRTM): Bringing Water to the Sinai desert

Shuttle Radar Topography (SRTM DEM) image of the Sinai Peninsula overlain with the extracted drainage network of Wadi El-Arish (channel lines within the watershed are shown in white). 

Credit: Radarsat-1/Shuttle Radar Topography Mission (SRTM)

According to a new study co-authored by CAS researchers, the traces of an ancient watershed in the Sinai Desert may hold clues to making sustainable agriculture possible in one of the driest places on earth.

Farouk El-Baz, research professor and director of Boston University's Center for Remote Sensing, and Mostafa AbuBakr, a visiting scholar at the Center, were part of an international team of scientists who used advanced space-borne radar to reveal how water flowed through the Wadi El-Arish in less arid times—about five to ten thousand years ago.

That discovery opens the possibility of capturing water from seasonal downpours by channeling it to the Wadi's central basin.

Their findings appear in the April 2013 edition of the journal Geomorphology. The Egyptian Sinai Peninsula, an extension of the Great Sahara, is among the driest deserts on Earth, but that wasn't always the case.

Geological evidence indicates that the Eastern Sahara has undergone climatic fluctuations of wet and dry episodes over the last two to three million years, with the last major wet cycle occurring between 9,500 and 4,500 years ago.

Spot 5 satellites

Wadi El-Arish is one of the ephemeral rivers that were active during these wet phases, although at present, the tributaries of Wadi El-Arish are dry, channeling the occasional flash flood northward over the central carbonate plateau of Sinai, toward the Mediterranean Sea at El-Arish City.

Although northeastern Sinai receives the largest amount of rainfall in Egypt (~ 304 mm annually), lack of freshwater resources continues to impede sustainable development in the Sinai.

Because Wadi El-Arish has the largest watershed in the Sinai and collects over 60 percent of the peninsula's precipitation, it is being closely studied for its potential to make possible sustainable agricultural development in North Sinai, based on the renewable runoff and the potential groundwater of its paleolakes.

The success of this process depends on identifying and using the ancient course of the Wadi to channel and capture this runoff.

The present study used remote sensing and geographic information systems (GIS) to delineate the former shape and flow direction of Wadi El-Arish before recent uplifting and explain the causes that led it to deviate from its original course.

The study also mapped paleolakes along the former river course and estimated the amount of water held in the lakes.

An important outcome of this study includes establishing an approach that integrates remote sensing data, geomorphology and geological structure to understand the paleodrainge evolution and its implications on groundwater potentiality, which could be applied to the study of arid lands around the world.

The researchers used space-borne radar images, provided by Radarsat-1 and the Shuttle Radar Topography Mission (SRTM), to recognize paleodrainage features.

Optical satellite images by the Landsat ETM + and the high-resolution images of GeoEye and Spot 5 satellites aggregated in Google-Earth were also used as supplementary data.

The optical data were employed for visual interpretation of surface features and paleolake sediments.

More information at Science Direct