Water quality deterioration study in some wells in Ghadames Basin West of Libya

الملخص EN

The present study focuses on Al-Hamada Al-Hamra Basin “Ghadames Basin” in the northwestern part of Libya in the area between the (30.

00 and 30, 20) latitudes and the longitudes of 30° and 10° East, and both Tunisian-Algerian border in the west.

Ghadames Basin contains several underground reservoirs, such as the deepKiklah aquifer, which is widely used in many areas within the basin currently.

This reservoir is located at a depth of 500 meters.

The thickness of water-bearing layers varies from region to region within the basin boundary.

In some areas, the thickness reaches 500 meters, and the depths Libyan bulletin for studies – twenty- first issue Water Quality Deterioration Study in Some Wells in Ghadames Basin West of adel ahmed auhida , ali abdulsalam jarad of the wells that penetrate it reaches more than 1,000 meters.

The level of static water ranges from several meters below the surface to about 40 meters above the surface (Al-Futtaisi et.al, 2007).

Total soluble salts in its water range between 800-1500 mg/L.

In some areas, the temperature of water in these wells reaches 400 °C (Radhi, M.

2006).

There is an important phenomenon connected with the exploratory drilling of the wells in the area.

A sudden rise in water salinity is observed briefly during pumping from some wells that exploit the deep Kiklah aquifer exceeding the permissible limits and for the specified periods.

This concentration reaches about 19,000 mg/L.

Also, there is a lack of hydrostatic pressure in wells especially after being locked as well as the disappearance of the artesian property with a significant decrease in productivity (Radhi, M.

2006).

Therefore, the current study is concerned with studying the reasons for the low quality of water, temporary increase in salinity, in addition to the sudden decline in productivity, and the lack of hydrostatic pressure in some wells that exploit the deep aquifer, depending on the review of the previous studies conducted on the region and their follow-ups, geological and hydrogeological characteristics and the characteristics of the drilled wells and the specifications of drilling, processing, design, and completion, and conducting chemical analyses of water samples and comparing them with previous analyses will enable the researcher to identify the causes of these phenomena, and the factors affecting the wells that are located nearby or the ones to be excavated in the future.