The Libyan Journal of Science

Groundwater Modeling & Risk Management Impact of Groundwater Extraction on land Subsidance in Sarir Area East Central Libya

Nabila A. Altuwibi — 2024-10-30

This research was conducted to study the impact of exploiting groundwater on ground subsidence in Sarir water well fields, East central Libya. There are three major water well fields in this area. Known as North and South Sarir agriculture projects, they are operating since 1975, each has 239 drilled water wells at depths of 300 meters , used for irrigating of 100 hectares. the third well field belongs to the Man-made River Project, where 126 production wells(1MM³/day) drilled at depths 450m, they were operating since 1992. A comprehensive amount of data were collected on groundwater abstraction and water levers monitoring program Data such as well discharge and the drawdowns were made available for 63 observation wells covering the area of the well fields. There are two main aquifers in the area, the upper (shallow) aquifer with thickness about 150 meters and the deep aquifer is about 800 meters. These two aquifers are frequently separated with about 50m lentecular layers of clay and silt.All possible collected hydrogeological data were prepared in order to be used and build a conceptual and numerical groundwater model. This process should lead to understand the hydraulic behavior of the groundwater system in the whole area of study. The model was used to correlate the calculated hydraulic parametrs with the observed for calibration and verification. The model was also used to predict the future drawdown and land surface subsidence exerted, due to stresses forced by the long period groundwater abstractions from the three well fields.The total extracted water is 6.872 bm³since the start of the welfields to the end of 2012. The results obtained from matching the observed drawdowns with the model predictions are as follows: Specific yield and Storage Coefficient obtained from this model ranges from 0.003 to 0.12 and from 4x10^-7 to 4x10^-3respectively, elastic skeletal specific storage from 4x10^-7 to 5x10^-2, and inelastic skeletal specific storage for thin interbeds is in the range from 4x10^-5 to 5x10^-1. The model then used to predict the drawdown and landsubsidence after 50 years of existing and planned exploitation. The maximum drawdown is predicted to be 55meters with land surface subsidence of 2.8 meters.

Modeling of groundwater dynamics and the impact of development scenarios at Sarir wellfield

Salem Elsakran — 2024-10-27

The study area (Sarir field) is part of the man-made river project (MMRP) in Libya. The wellfield includes 126 production wells aligned on three parallel east-west lines, 1.3 km between the wells on each line, 10km between the three lines and includes over 24 exploratory and piezometric wells. The wellfield has two relatively separated aquifer systems: a shallow unconfined aquifer of Post Middle Miocene age and a deep semi-confined aquifer of the Middle Miocene age; both are composed of multi-layered sand, silt, shale, siltstone, and clay. The study aims to construct a Three-dimensional numerical model using finite difference method to simulate deferent development scenarios of the wellfield. Processing Modflow for Windows (PMWIN) had been used to construct, calibrate, optimize production, calculate budget and predict the drawdown of various development scenarios. At present, the Sarir well field produces approximately 600,000 m3/day and is planned to produce 1,000,000 m³/day in the future. The subsea depth to the top of the main aquifer is around 220 m, and the main aquifer thickness is around 250 m. A very good record of groundwater levels and water production data since it started on 1/1/1999 and up to 30/8/2005 is available for transient calibration. 140 boreholes have been used in the model and checked as active to benefit from most of the available data. A steady-state calibration has been performed against very well defined drilling information. A very good match between the simulated and the initially specified heads has been achieved. The transient simulated time is 2400 days, including 40 stress periods, during which the wellfield produced 714910755 m³, where a reasonable match between the measured and calculated water heads has been attained in the majority of the piezometer's hydrographs. Three operation scenarios with differing locations of the planned new wells have been made; the best was the second one, in which the new wells are along the three well field lines since it has the lowest maximum drawdown recorded (25 m) and the least reduction in storage (128000 m³). For the sake of additional assessment, additional model calibration is needed, to benefit from a large number of piezometers and exploratory wells available; this can only be attained if the water levels and production rates in the wellfield are recorded in smaller and more regular time intervals.

الحماية القانونية من التلوث المائي

فرج حسين فرج الحاسي — 2024-10-30

Given that the aquatic environment is one of the environmental frameworks in which man lives, and because man is an influencing factor for this environment, it is necessary to organize his relationship with it in order to preserve it and prevent any change in it or harm the various organisms that live in this environment in the future.

And since the privacy of the water environment and the imminent danger it represents in the event of a change in its natural characteristics, the Libyan legislator has followed many policies in many relevant national laws, all of which aim to protect it, based on his view that the water environment is in continuous and increasing deterioration, either through pollution or exploitation. faulty or corrupt.

Through this research, we focus mainly on what is the crime of water environmental pollution in the first requirement, We deal with the definition of water environmental pollution in the first section, and the elements and characteristics of the crime of water pollution in the second section. In the second section, we discuss the policy of the Libyan legislator in protecting the water environment, and shed light on the legal protection of the marine environment in the first section, and the legal protection of groundwater and water bodies in the first section. Section two.

الإمداد المائي مابين التحديات والصعوبات في ليبيا في الفترة (2019-2021)

كريمة أحمد بركة — 2024-10-30

Water is an essential resource for economic, industrial, and social development in all nations. However, Libya is considered a water-scarce country due to its limited and non-renewable water resources, with around 92% of its supply derived from groundwater. The General Company for Water and Sanitation oversees the distribution of water from various sources, which include 60% from the Great Man-Made River, 10% from seawater desalination, and 30% from groundwater wells. In recent years, there has been a significant decline in water supply.

This study examines the distribution practices of the General Company for Water and Sanitation across different regions, particularly during the challenges faced from 2019 to 2021. The average water supply per person is estimated to be about 250 liters daily. Data shows fluctuations in the available water supply, leading the company to explore solutions to improve water availability. By 2021, the distribution sources had changed to 50% from groundwater, 49% from the Great Man-Made River, and 1% from seawater desalination. After accounting for technical losses, the water deficit in 2021 was approximately 6%. The company is actively working to mitigate this deficit by addressing the challenges it faces and developing proposals and solutions to enhance water supply efficiency.

حالات امتلاء بحيرة بلطة الرملة خلال الفترات 1986 - 2018 ومواسم2022/2023 باستخدام التقنيات الحديثة

محمود الصديق التواتي — 2024-10-27

A case study ,Al Ramla Baltat lake, this site is located within the southern boundary Al Jabal al-Akhdar region, about 14km south of the Al-Mukhaili vecinity where a temporary important natural lakes , in its catchment area created by torrents and floods. formed in a typical land composed of alluvial sediments, and it is a natural outlet for stream waters flow on the southern slope of Jabal al-Akhdar. The study aimed to The volume of water accumulation in the Balta Rainwater Lake during the 2022-2023 season, from the day it was filled on 11/27/2022 until its depletion in the dry season on 07/03/2023. The stages of the lakes’ emergence were also traced during the period 1986-2023, according to tracking images. satellite for the American Landsat 8 and the Sentinel A2l2 combat satellite. The author used layers and the analytical compositional approach based on visual data of the two satellites, aided by topographical and geological maps. The study was written. Image and map data were contributed to the ArcGIS era after and corrected using the eos.landviewer website, and using the NDSI tool. Measuring areas for pictures of the stages of the lake’s water lake thanks to loosed . The designers were surprised at the length of the follow-up period, and a small-scale attempt was made to mathematically flow the Ramla Valley. Based on the above, I set out to listen and patterns to reach the function in stages on the shores of the lake until its scars. It supported the temporal study during the period the study.

The study found that the volume of water collected in the Ramla lake during 2022/2023 season was about 9.8 million cubic metres, and that its water dried up 100 days after it was filled, and that the daily loss of the lake was 98 thousand cubic meters per day. The volume of water collected during the period 1986 - 2023 amounted to 367.3 million cubic metres. The study recommends investing in the lake's water by developing trenching technology in the Ramla area by creating an artificial lake of more than 8 meters deep to accommodate larger quantities of water.

تقييم وضع المياه الجوفية في محلة السواوة - مصراتة سنة 2021 وتأثيراتها البيئية باستخدام نظم المعلومات الجغرافية

فاطمة صالح إبشير — 2024-10-27

The research aims to assess the current status of groundwater properties in Al-Sawawah area. The Mahjoub-Misurata Area in the years 2021, based on the results of Ph. Electrical conductivity (EC), total dissolved salts (TDS), and some negative and positive ions of 13 groundwater samples. In addition, geographic database is built to produce digital maps using Arc GIS10.8. The results show a spatial discrepancy in the distribution of the qualitative characteristics of groundwater, where the pH values ranged between 6.94 and 7.50, while the values of the total dissolved salts were between 4556 and about 1198 mg/L. These values, the groundwater exceed the permissible limits according to the Libyan and international specifications for different use, especially domestic and agricultural uses. Furthermore, the electrical conductivity values range between 1788 and 6800, and the water was very hard according to the Todd classification, where the total hardness exceeded 301 mg/L, and the concentrations of calcium in groundwater wells were between 120 and 400 mg /L. The average chloride was recorded between 532.5 and 1881.5 mg/L with the evident indicators of agricultural land degradation and desertification. The study produced digital maps showing the geographical distribution of the groundwater properties and its spatial difference in Al-Sawawah locality.

حصر وتقييم العيون المائية الطبيعية ببلدية البيضاء في الجبل الأخضر

فرج سليمان عبدالرحيم مازق — 2024-10-27

In this study, 22 natural water springs spread on the second edge of the Green Mountain in the municipality of Al-Bayda were counted and evaluated. productivity, use and exploitation.

Twenty Samples were collected from these springs in February 2023, and these samples were analyzed in the laboratories of Al Baydah Food Control Center and the laboratories of the Susah desalination plant, the results then comparing with these values of the Libyan standard for drinking water (2015) concerned with the physical characteristics of drinking water, inorganic indicators and inorganic contents Organic and microbial pollution (bacterial), it was found that 5 natural water springs are not suitable for drinking due to their microbial contamination with Coliform bacteria, and 15 natural water springs are suitable for drinking according to the Libyan standard, and 2 of the springs were not sampled for technical and natural reasons.

النهر الصناعي ودوره في تحقيق الاستدامة المائية في ليبيا

صالح أمهني — 2024-10-31

The aim of this study is to focus on the role of the Man Made River Project (MMRP) in the resolvingand the mitigating of the crucial water shortfall in Libya. An Analytical descriptive program was utilized to achieve these goals.Libya is considered to be one of the poorest counties in regard to the availability of renewable water resources. However, enormous volumes of groundwater in reservoirs are located in the southern part of Libya and hence it was necessary to transport the water from the south to the more populated areas in the north.

It was concluded that the MMRP provided water for more than 70% of Libyan cities and therefore,it was the ideal solution for the water supply issue to meet the increasing demand for the agricultural, household and industrial purposes. Since the main water supply in Libya is from a non- renewable source, it is necessary to take all the necessary measures to maintain and protect this precious source of life. Such measures include continuous maintenance, sabotage prevention, and public awareness and searching for alternatives sources of water to reduce the burden on the MMRP .