The main karstic springs in central Al Jabal Al Akhdar are mostly producing water from the Eocene aquifer of Darnah Formation. In particular, Al Dabusiah spring is discharging at the contact between the low-permeable unit of Apollonia Formation and highly transmissible karstic unit of Darnah Formation as the main aquifer. The present study indicates that the fresh water of Al Dabusiah spring has Electrical Conductivity (EC = 870 µS/cm) and the Total Dissolved Solids (TDS = 530 mg/l). This spring has maximum discharge rate varied through time from 1952 to 1985 reached 265 l/s (22.8 × 103 m3/day) and 220 l/s (19 × 103 m3/day), respectively. However, in August 2022, the authors recent flow measured a total amount of 223 l/s (19.2 × 103 m3/day) recorded at the most reachable point inside the tunnel. Part of this amount [107 l/s (9.2 × 103 m3/day) is pumped to the Municipalities of Al Qubbah, Al Abraq, and east of Al Bayda cities, taking into account the unlawful pumping by the local citizens that affect the amount of water reaching each city. The other portion of the amount [116 l/s (10 × 103 m3/day)] measured at the gate of the tunnel is unused and freely flowing to the wadi channel due to only one pump is functioning in main pumping station. The groundwater pumped from Al Dabusiah spring is directly transported to the main filtration tanks that re-pumped to the distribution network and then to the nearest municipalities. Since the source of the spring water is fresh and contamination free, there are some signs of chemical and biological contaminates within the spring, pumping station, and distribution network due to deficiency in chlorination program. Although, the flow rate is generally high through time, the spring was steadily recharged due to the following conditions; high elevated area (450–650 m a.m.s.l), high fractured karstified carbonate formations, high infiltration rate (2–8.9%), low evaporation rate, and high precipitation (~ 700 mm/yr). Since the total surface area of Al Dabusiah village has increased five times from 0.24 in 2000 to 1.21 km2 in 2023, consequently, the population has drastically increased up to 8000 people. The demands of water supply subsequently increased caused severe shortage of water supply to Al Qubbah city and surrounding villages. Given to this, the above-mentioned results have a serious impact on the social habitat and sustainable development protection of the natural resources. To achieving the continuity of the minimum development of the basic water resources, the water balance between demands and resources should be protected. However, the problem is the absence of a reliable management and lack of governmental policy in order to prevent water misuse and pollution.

Discharge variability, recharge conditions, and water supply challenges of Al Dabusiah Karstic Spring, Al Jabal Al Akhdar, Eastern Libya

期刊论文
发表日期：

2025年7月7日

查看全文

H. El-Shawaihdi Moftah,
M. Ibrahim Nafisa,
M. Awami Younis,
H. Al Riaydh Mohamed,
M. Salloum Fathi

摘要

The main karstic springs in central Al Jabal Al Akhdar are mostly producing water from the Eocene aquifer of Darnah Formation. In particular, Al Dabusiah spring is discharging at the contact between the low-permeable unit of Apollonia Formation and highly transmissible karstic unit of Darnah Formation as the main aquifer. The present study indicates that the fresh water of Al Dabusiah spring has Electrical Conductivity (EC = 870 µS/cm) and the Total Dissolved Solids (TDS = 530 mg/l). This spring has maximum discharge rate varied through time from 1952 to 1985 reached 265 l/s (22.8 × 10³ m³/day) and 220 l/s (19 × 10³ m³/day), respectively. However, in August 2022, the authors recent flow measured a total amount of 223 l/s (19.2 × 10³ m³/day) recorded at the most reachable point inside the tunnel. Part of this amount [107 l/s (9.2 × 10³ m³/day) is pumped to the Municipalities of Al Qubbah, Al Abraq, and east of Al Bayda cities, taking into account the unlawful pumping by the local citizens that affect the amount of water reaching each city. The other portion of the amount [116 l/s (10 × 10³ m³/day)] measured at the gate of the tunnel is unused and freely flowing to the wadi channel due to only one pump is functioning in main pumping station. The groundwater pumped from Al Dabusiah spring is directly transported to the main filtration tanks that re-pumped to the distribution network and then to the nearest municipalities. Since the source of the spring water is fresh and contamination free, there are some signs of chemical and biological contaminates within the spring, pumping station, and distribution network due to deficiency in chlorination program. Although, the flow rate is generally high through time, the spring was steadily recharged due to the following conditions; high elevated area (450–650 m a.m.s.l), high fractured karstified carbonate formations, high infiltration rate (2–8.9%), low evaporation rate, and high precipitation (~ 700 mm/yr). Since the total surface area of Al Dabusiah village has increased five times from 0.24 in 2000 to 1.21 km² in 2023, consequently, the population has drastically increased up to 8000 people. The demands of water supply subsequently increased caused severe shortage of water supply to Al Qubbah city and surrounding villages. Given to this, the above-mentioned results have a serious impact on the social habitat and sustainable development protection of the natural resources. To achieving the continuity of the minimum development of the basic water resources, the water balance between demands and resources should be protected. However, the problem is the absence of a reliable management and lack of governmental policy in order to prevent water misuse and pollution.