Evaluation of the Nubian sandstone aquifer system (NSAS) in Al Kufra Oasis Northwest LibyaSalah M Hamad1, Younes A Ahweej21(Lecturer ) Faculty of Natural resources and Environmental science , Omar Al Mukhtar University, Al Baydah, Libya. 2(Researcher ) Libyan Agriculture Research Center .
AbstractWater resources in Al Kufra oasis vulnerable due to increasing pressures to meet the demand for economic development represented mainly by agriculture activities, in addition to the inefficient use of water by other consuming sectors. The misuse and violations as a result of the country political instability, in addition to the lack of effective legislation, policies, strategies, and law enforcement instruments in current Libyan water management practice. Therefore this research highlights the water situation for Al- Kufra oasis in term of water quantity, and water quality, as well as the current management practices of the water resource.The study evaluated the water resources in terms of quantity through water level measurements in 10 piezometric wells for the period from 2005 to 2015 those shows drawdown value about 20 meters during ten years in the urban area and the agriculture projects areas.
In term of water quality, water samples were collected from 16 water wells, and chemical analysis was conducted for the concentration of major anions and cations. The result shows increase in the value of total dissolved solids in the urban area and the agriculture projects areas which can be interpreted as the result of the increase in the amount of water extraction or it may be caused by the contamination due to the urban activities, also. The groundwater classified according to Piper diagram that indicates the water is (Na-Ca-Mg-Cl) type, also Wilcox diagram indicates that water is good for agricultural purposes. For water resources management practice the survey was conducted by inquiring for; water institutions, institutional framework, functions, activities, and their influence in the current management. The study showed the lack of proper water management due to the absence of proper involvement for the most of Libyan state water institutions and relevant stakeholders which led to the lack of performance and involvement of stakeholders in the process of water resources management. It is clear the challenge is the current management practice water resources rather than technical aspects . Therefore a comprehensive reform of the water sector is needed with capable laws and regulations to sustain water resources ,as its recommended to engage the academic institutions ,and relevant NGO as main stakeholders to form initiating team for Integrated water resource management (IWRM) planning processes and increasing the awareness through workshops or conferences that can ensure the required awareness to the government officials as well as the capacity development that must be implemented urgently to ensure sustainable management of the resource.Keywords: Groundwater, water resource, Libya, NSAS1.
Introduction The majority of the Libyan land is categorized under Arid to Hyper-arid regions. About 90% of the land is forms of deserts characterized by Low rainfall rates, diurnal temperature variations, poor soils, and seasonal winds. Groundwater accounts for 97% of total water abstracted for different uses, where the county total abstraction 4.98 billion cubic meters per year. (GWA,2006). The depends on the NSAS aquifer mostly on the middle and eastern parts of the country, while other regions of the country depend on the other groundwater basins NSAS has important significance to settlements those depending on the water abstracted for domestic and the irrigation of the agriculture projects that provides the crops to the residents of the NSAS area and the rest of the Libyan state. The country’s political conflict and uprising lead to some kind of disruption of the system and difficulty in monitoring and managing water resources. Therefore this research discusses the current situation of the NSAS aquifer in Al Kufra Oasis.
The Nubian Sandstone Aquifer System (NSAS) as illustrated in figure (1) is the world’s largest known fossil water aquifer system. It is located underground in the Eastern end of the Sahara Desert and spans the political boundaries of four countries in north-eastern Africa. This Aquifer covers a land area spanning just over 2.2 million km2, including north-western Sudan with an extension of 376.000 Km2, north-eastern Chad with an extension of 235.000 km2, south-eastern Libya with an extension of 760.000 km2, and most of Egypt with approximately 80% and extension of 826.
000 km2 (Ahmed,2013).Fig (1) NSAS location map(IAEA,2013).2 Geology of Al Kufra Desio in (1935) introduced the term Kufra/Al Kufrah as the general name to all geological sequences, where the greater part composed of quartzitic sandstones, which form the area of Al Kufrah group or series. The sediments of the Al Kufra basin are mainly continental cross-bedded sandstone intercalated with argillaceous clays and shale (Klitzch,1970 ) that corresponds to the “Nubian Sandstone” in the southeastern part of Libya.
The Nubian sandstone of the Al Kufra basin has a maximum thickness of 900 m and includes mainly cross-bedded sandstone, intercalated with clays and shales.Table (4) illustrates a general stratigraphic geological succession of the Al Kufra basin (Salama and El Ebaidi, 2016)Table (4) General sedimentological succession of the Kufra basin (Salama and El Ebaidi, 2016)Age Formations & approximate max. thickness (m) Lithology & depositional environmentRecent/Pleistocene 100 m Sandstone and Sabkhat deposits Lower Cretaceous Nubian Sandstone(900 m) x-bedded sandstone, shale and conglomerates Carboniferous 800m Continental sandstones Devonian Tadrart Sandstones(100 m) Massive, continental x-bedded sandstones with fossil plant marginal marine deposits Silurian TanezzuftShaesAcacus Sandstones (90 m) Sandstones, marine with fossils. dark shale and silty with fossils Ordovician Gargaf Group(700 m) x-bedded sandstones with some silty shale (continental/marginal marine deposits Pre-Cambrian Basement Folded metamorphic and granitic igneous rocks 3 Groundwater resources of Al Kufra3.1 The Aquifers The Kufra basin consists of two main aquifers (Salem, 1996):First aquifer the Paleozoic It is composed of thick layers of Nubian sandstone of the Cambro- Ordovician, Silurian, and Devonian ages, that intercalated with layers of clay and outcrops on the southern and northeastern parts of the basin, where it dips in the other parts of the basin to depths of more than 800 meters with a varying thickness between 3000 and 1000 meters.
Also noted that the water of this aquifer is not yet exploited due to its presence at deep depths. Second aquifer the NSAS Consisting of layers of loose sand, silt, and mud, with fewer sandstones and some other sedimentary rocks and divided into:Shallow Aquifer The water level of this aquifer extends from depths of 150-80 meters, and the total dissolved solids (TDS) ranges from 8000-300 ppm due to the existence of an old sabkah. Deep AquiferStarts from a depth of 400 to 800 meters ,the TDS of this aquifer ranges from 8000-300 ppm due to the existence of an old sabkah.
3.3 Current situationWater useThe total abstraction from NSAS in Libya estimated by 969.5 Mm3 per year for all water uses, as the increase in population there is corresponding growing demand for freshwater for domestic, agriculture and industrial purposes, where about 964100 inhabitants in 74 human settlement dependent on NSAS for domestic use , where the agriculture abstraction estimated by 504 Mm3 per year ,where 7011 for agriculture use for different crops as in the tables (1), (2),and (3).For industry only the oil industry represents the highest consumer for production oil by water, the amount of water abstracted is estimated from the available data as 130 Mm3 per year.Table (1) Type and number of crops (GAALMR,2018)Olive Palm Almond Apple Citrus fruits Grape Figs Other types446279 1484990 3797 5060 18509 163604 37733 139385Table (2) Type and production in tons for harvest (GAALMR,2018)Wheat Barley Cane Animal feed Beans37920 34364 4255 95747 180Table (3) Type and number of crops (GAALMR,2018)Sheep Goats Camels238291 91609 47106In Al Kufra oasis the water use for agricultural purposes is the greater use compared to other uses, as shown in the table (5). Unaccounted water use represented in water supply, where remarkable frequent explosions noted in the main and secondary pipelines, due to the weakness of the current network, in addition, the most of the main and secondary pipelines violated when passes through by the private farms. Also, several new residential neighborhoods Built randomly out of the main urban plan which is does not have public facilities.
Table (5) Table showing the number of wells, pumping and towing rates for Kufra area(GAALMR,2018) Depth(meter) Aquifer Abstraction Million cubic meter per year Project name Use250-300 Deep 176 Al kufra production project Agriculture450 Deep 32 Al Kufra settlement project 50-120 Shallow 33 Palm Project 50-150 Shallow 75 Private farms Domestic and Industrial250-450 Deep 26 Domestic and water bottling industry 342 TotalGroundwater levelsThe data of groundwater levels in Al Kufra region were collected from piezometric wells, as in table (6) and mapped using geographical information system techniques as illustrated in the figures (3)and (4). In the year 2005 the average water level about 20 meters, where the lowest level was 2.35 meters at the southwestern part of the oasis, while in urban area and the agriculture projects areas water level depth reach to 53 meters. In 2015 the average water level was 26 meters, where the lowest level was 4.4 meters at the southwestern part of the oasis and in the urban area and the agriculture projects areas water level depth reach to 53.5 meters. The drawdown in groundwater levels in Al Kufra area in 10 years presented in the figure (5) where the average drop of the water level about 5.
7 meters. It is noted there is a significant decline of water level the area in urban area and Al Kufra production project which recorded the highest value of drawdown that estimated by 20 meters unlike other areas of the oasis.Table (6) Groundwater levels in peziometric wellsWell no Water Level meterYear 2005 Water Level meterYear 2015 Drawdown meterPZ-O4 13.54 18.
72 5PZ-6 25.86 36.74 11PZ-8 2.35 14.14 12PZ-O8 5.00 14.
89 10PZ-9 25.04 26.56 2PZ-O9 30.28 29.
96 0PZ-10 41.11 41.66 1PZ-11 6.59 21.68 15PZ-13 35.98 51.18 15PZ-14 29.62 35.
19 6PZ-15 17.80 29.31 12PZ-16 32.10 42.19 10PZ-17 6.
30 13.32 7PZ-18 12.88 23.61 11PZ-19 10.80 31.19 20PZ-25 10.
82 13.06 2PZ-26 22.22 25.85 4PZ-27 53.01 53.80 1PZ-28 28.31 29.
84 2PZ-30 19.85 21.05 1PZ-31 51.84 52.
40 1PZ-32 22.64 24.85 2PZ-33 40.25 41.
00 1PZ-35 3.77 4.40 1PZ-36 10.
74 11.56 1PZ-37 13.54 16.50 3PZ-2311 7.
50 9.21 2PZ-2232 8.97 10.87 2PZ-2122 6.86 10.
40 4The impact of drawdown of water level in the oases ecosystem can be concluded as;Effect on the growth of palm trees, and other desert species Drying of water bodies such as small sabkha, which leads to the migration of some of the living species that live on themLand subsidenceFig (2) Groundwater level map year 2005Fig (3) Groundwater map year 2015Fig (5) Drawdown in groundwater level mapGroundwater qualityAccording to the results of the chemical analysis of water samples in the region as showed table (7), the total dissolved solids of groundwater aquifer range from 172 to 900 ppm. The map of total dissolved salts (TDS) in figure (6) shows increasing in urban area and the agriculture projects areas rather other areas of the oasis which can be interpreted as result of more abstraction or possible contaminations since most of the city’s neighborhoods and suburbs do not have sewage networks.. The water type was defined according to Piper’s diagram as in figure (7) that indicates the water is (Na-Ca-Mg-Cl) type, also Wilcox diagram in figure (8) that indicates the water in Kufra is good for irrigation and is classified in terms of quality for agricultural purposes Table (7) Results of chemical analysis of water samplesPotassium mEqSodium mEqMagnesium mEqCalcium mEqSulfate mEqChloride mEqBicarbonate mEqTDS(ppm) pH Well No0.16 1.74 0.7 1.2 1 2.
1 0.7 387 6.8 10.
17 1.74 0.9 1.3 1.21 2.2 0.7 387 6.
78 20.12 0.7 0.
4 0.7 0.52 0.7 0.
7 172 6.83 30.23 5 1.3 1 1.63 5.1 0.8 660 6.
84 40.78 6.52 1.5 1 2.5 6.
6 0.7 823 6.78 50.26 3.
91 1.7 1.2 2.47 3.9 0.7 612 6.
87 60.21 3.26 1.6 1 2.07 3.
4 0.6 537 6.98 70.17 1.
61 1.1 1 1.18 2.1 0.
6 365 6.94 80.28 5 1.2 1.
3 1.78 5.4 0.6 704 7.
08 90.14 1 0.5 1.1 0.74 1.3 0.
7 237 7.17 100.1 0.82 0.5 1 1.22 0.5 0.
7 211 7.1 110.18 1.3 0.6 0.7 0.
88 1.2 0.7 260 7.
1 120.19 1.22 0.6 0.
7 0.86 1.2 0.
65 233 6.99 130.17 1.65 0.9 1.3 0.92 2.
1 1 401 7.07 140.25 3.
69 0.9 0.9 1.
64 3.3 0.8 512 7.04 150.17 1.
48 0.8 1 0.85 1.9 0.7 343 6.
96 16Fig(6) Total dissolved solids mapFig (7) Piper’s diagramFig (8) Wilcox DiagramGroundwater management Most of the government water institutions in Libya established through decisions from the Ex-Ministerial Council, After the political change in 2011, the government in 2012 establish the ministry of the water resource to be the highest authority for water resource in Libya to supervise and administrate all the water institutions. The ministry of water resource turned after 2 years to the name the National Water Resources Establishment with the same tasks. Water institutions were characterized by less administrative stability, and overlaps in responsibilities, in addition to the centralized approach in the management .Responsibilities and tasks of the working water institutions in Al Kufra oasis can be summarized as in the following (WSP, 2011; GCWW, 2018; JA, 2018): The General Water Authority (GWA), formed in 1972 and responsible mainly for ground water resources exploration, monitoring ,supervisor on the drilling of the water, and ground water regulation . The General Company for Water and Wastewater (GCWW) Established in 1996 responsible mainly in water supply; construction, operation, maintenance of transmission, distribution networks, water pumping stations, and control centers, to ensure the provision of better services to the users of them.
In addition to the construction, operation, and maintenance of drainage systems and related treatment plants, filtration, pumping, and monitoring. The Joint Authority for NSAS (JA)An authority has been established in 1989 between the signed countries of Libya ,Egypt, Sudan and Chad under the name “Joint Authority for the Study and Development of the Nubian Sandstone Aquifer Waters” The Authority has been established to carry out the following objectives:Study, development and investment of water resources in the Nubian Sandstone Aquifer System and strengthen the regional corporation between member states.Protection and maintenance thereof and nationalizing their use and harnessing them for searing the overall economic and social development.Development in the participant countries and the formulation of a regional strategic action plan for the sustainable utilization of the Nubian Sandstone Aquifer System and create a rule for the formulation of a regional development strategy.These institutions suffer from the lack of highly qualified water professionals in the region, due to the limited income that the state paid, this has made most specialists to move to the private sector or to join other institutions outside the oasis to meet their daily needs. Also, institutions face the multiplicity and conflict of interests of water, in addition to their monopoly there are no implementations of the legislation, policy, and strategies, with complete absence law enforcement instruments.
GCWW is the only institution largely operating and suffers from many challenges and difficulties, some of which are the problems of the old water networks and the explosion of transmission pipeline , and absent of the sewage treatment ,in addition to the violations on water utilities . However, the company suffers from the lack of adequate financial coverage to perform its tasks as required.GWA introduced in 2006, policies and strategies concerning the delineations of risk areas for groundwater utilization those very efficient regardless of the current political situation that limits the monitoring and implementations. Also, the General Water Authority has a limited representation in the area in terms of the presence of specialists, offices, and laboratories to monitor and prepare hydrogeological studies, which will raise awareness and ensure the implementations of the policies and the strategies in the region.The JA is only linked to water governors and main water stakeholders at the national in Libya. And needed to be in link with academia.
The countries participating in the Commission shall bear the Commission’s budget in equal proportions for each of them. JA is needed to be reformed at the national byIncreasing qualified staffing Enhancing monitoring systemUpgrading the information systems ,and support it with modern technologies Supporting national capacity building programsAlso ,The JA needs more political support at the national level through organizing meetings, conferences, and workshops for demonstrating its activities at the national and regional levels to ensure the political commitment that will be the driver to financial support by the national government .Also restructuring the JA in a way that allows the increase of experts and staff to ensure more geographical engagement for the areas of NSAS at the national level.Also, there is no participation of NGOs especially those specializing in water and environmental issues as well as the lack of water awareness activities. Table (8) present the enabling environmental indicators and institutional arrangementTable (8) Enabling environmental indicators and institutional arrangementIndicator Unit Year :2018Water resources policies based on IWRM principles Yes/No No Water institutions Number 3Inter-institutional integration Yes/No NoStakeholder participation Yes/No NoThe existence of a supreme national authority Yes/No YesApplication of laws to violators of the Water Law Yes/No NoAcademies that provide training in the field of water in the region Number 0Awareness and water awareness activities per year Number/YEAR 0Conclusions and recommendationsThe NSAS is a valuable water resource but it mismanaged properly in non-integrated approach will have negative impacts. the issues of increasing water demand driven by population growth and urbanization and uneven distribution of water resources and quality degradation were not taking into account for water resources management in Al Kufra oasis, therefore the challenge of is the way of management rather than the technical challenge.The resulting of assessment of the current water resource situation in Al Kufra oasis can be summarized in the following point:Centralized planning and financing and limited financial resources Tasks overlap of water institutions , lack of coordination, and Organizational instabilityInadequate institutional capacity at regional and local levels and limited experience in integrated water resource managementParticipations of the stakeholdersInsufficiently reflection of socio-economic dimensions Limited capacities in water management and lack of skilled labour to cope the future challengesLack of organized approach of awarenesslimited Monitoring system and lack of data quality These issue should be taken into consideration for the proper management of the this precious resource ,therefore the following recommended action should be implemented in order to achieve the sustainability Addressing issues that support institutional integration and engagement of the stakeholders to ensure the cooperation in the field of water resources and ecosystem.
Evaluation of the current status of the NSAS beneath the main oases in term of groundwater quality and quantity.Assessment of the environmental impacts resultant from different water uses on NSAS and Increasing the knowledge about the ecosystem and its challengesFilling the gap and reduce the ambiguity by providing a spatial experience in the field that will form different levels of technical knowledge on national and regional levels.Ensuring the engagement of socioeconomic aspects for future planning and development toward protecting the ecosystem.Achieving programs of capacity development and building to support the rational and equitable management of the NSASAssessment of socioeconomic conditions for the oases, and their direct and indirect relationship to the ecosystem.Assessment of the environmental impact as result of the exploitation from NSAS on the socio-economic aspects.ReferencesAbdulgader A.
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