An Assessment of the Hydrogeology and Hydrochemistry of the main Aquifers in Darnah Region, NE. Libya

Abstract

The aim of this paper is to evaluate the Hydrogeology and
hydrochemistry in the main aquifer in Darnah region, the Eocene
Apollonia and Darnah formations, which are exposed only in the
northwest center, and consists mainly of fossiliferous limestone;
perched aquifers from the Tertiary Oligocene ) Al Baydah and Al Abraq
Formations( and the Miocene Al Faidiyah Formation( in which the
limestone are contributing to the water resources in the eastern side,
Martubah area. Most of the southern part of the study area is covered by
the Neogene rocks of Al Faidiyah Formation. A number of chemical
analyses from previous consultant studies in the Darnah region were
reviewed and analyzed. In addition, more samples from different
localities were collected during June 2006. Some of these samples are
from pumped wells and others from natural flowing springs. The newly
performed analyses show a reasonable agreement with the previous data
whenever cross-checking was possible. The salinity of the main aquifer in
the western part of the study area shows a quite regular increasing trend

west to east and north to south (Fig. 4 and Fig. 8), the water quality trend
is matching closely to the groundwater flow direction. Many trials have
been performed to estimate the recharge of aquifers in the area. The climate of the study area has been discussed in order to understand
the relation and link with estimation of aquifer characteristics in terms
of recharge and water balance, these parameters are important for long
term water management for Darnah region. Climatic data were identify
the environment and further more classify the area in the range of weather
humid up to Desertic class. Water resources have been also discussed,
discharge measurements of springs were evaluated through the last
decades with respect with water wellfields in the upper stream.