Geology of groundwater resources in the reclaimed areas north of el Saff, eastern desert, Egypt

Abstract EN

Geomorphological, the El Saff area is classified into six geomorphic units, namely structural plateau, isolated hills, piedmont plain, alluvial fans, Nile flood plain and hydrographic basins.

It is dissected by four main canals with different ground elevations.

Three of them (El Hager, El Kashab and El Gabal) carry River Nile water with salinity ranging mainly from 220 ppm to 380 ppm (fresh water), while the other (El Saff Canal) carries treated industrial and wastewater released from the cities of Helwan and El Tabin, with salinity ranging from about 620 ppm to about 830 ppm (fresh water).

There are two main aquifer systems in the study area, belonging to Quaternary and Eocene units.

The Quaternary aquifer system is located in the western part, while the Eocene aquifer system is restricted to the eastern part.

They are hydraulically connected with each other through faults and intergranular flow.

The Quaternary aquifer system can be differentiated into Nilotic and alluvial aquifers.

The Nilotic Aquifer occupies a narrow strip adjacent to the River Nile.

It is recharged mainly from the River Nile, irrigation systems and the alluvial aquifer, which produce a variation in groundwater salinity from 288 ppm (fresh water) near the River Nile to 2040 ppm (brackish water) in the eastern part.

The alluvial aquifer occupies the alluvial fans of the main wadis and extends eastward to the piedmont plain.

It varies in thickness from about 30 to 60 m.

It recharged mainly from the El Saff and El Hager Canals, and the Eocene aquifer system.

Groundwater salinity in the alluvial aquifer ranges from 1040 ppm to 2950 ppm (brackish water) The Eocene aquifer system can be differentiated into Upper Eocene and Middle Eocene aquifers.

The Upper Eocene aquifer is located at the high relief areas of the piedmont plain with groundwater salinity ranges from 2410 ppm to 5360 ppm (brackish water), where it recharged mainly from El Saff Canal.

The Middle Eocene aquifer occupies most of the eastern part of the study area.

It is recharged mainly from the eastern watershed area and the El Saff Canal especially in the northern part, as indicated by the variation of groundwater salinity between 2750 ppm (brackish water) and 13000 ppm (saline water).

Most of the surface water samples are suitable for drinking purposes except the El Saff canal water samples, while most of the groundwater samples are not suitable except the Nilotic aquifer adjacent to the River Nile.

On the other hand, nearly all the surface and Nilotic aquifer water samples are suitable for irrigation of all crops, while most of the alluvial aquifer water is satisfactory for salt tolerant crops, but the Eocene waters are mainly not suitable for irrigation.