**5. Managing drought and water stress in Northern Africa**

Water stress is a growing problem worldwide. In Northern Africa, the demand for water is likely to increase while water supplies are reduced. This is driven by a combination of the rising population (coupled with economic growth) and more frequent periods of droughts which the region recognized especially over the last 4 decades, rendering water availability in the future uncertain. Groundwater tends to be overexploited and polluted to meet growing water consumption. Water stress and drought situations around Northern African countries constitute widespread two major phenomena (natural and human-made) that challenge water security, hence, all need to work together for better solutions of water issues as such, i.e., reuse of drainage wastewater, water desalination and rainwater Harvesting (RWH).

### **5.1 Reuse of drainage wastewater**

Rising population and long period of droughts exerted high pressures on renewable freshwater resources in Northern Africa over the last decades. This will lead to markedly greater competition between urban areas and farmland for water and thus producing more wastewater. Actually, the reuse of drainage wastewater is a great

## *Managing Drought and Water Stress in Northern Africa DOI: http://dx.doi.org/10.5772/intechopen.107391*

way to help protect the environment by reducing dependency on freshwater and meeting rising water consumption. Wastewater treatment is a process used to remove contaminants, micro-organisms and other types of pollutants from wastewater or raw sewage and convert it into an effluent that can be returned to the water cycle. Reusing wastewater is an obvious solution for the future to reduce water shortages in several regions on the Earth such as Northern Africa. After treating sewage, the treated wastewater can be reused for several applications such as irrigation purposes.

Egypt – Egypt's freshwater resources are limited. The gap between freshwater demand and supply is intensified by various combined factors including rising population and drought frequency. Reuse of sewage effluent in agriculture represents an opportunity that can alleviate the water stress on limited natural water reserves in Egypt. This process started in 1920 [44] and it is relatively less-infrastructure requirements to be constructed and cheaper option. The 1975 water policy for reuse of wastewater discharge had a target to decrease water stress on the Nile system and hence to increase cultivated areas and meet Egypt's growing food. Currently, this system is broadly applied in Delta region and produces approximately 4.0 BCM/year of wastewater discharge to be mixed with the freshwater of main canals. The Government's Planning for the Future is to reuse an additional 3 BCM/year. Besides these benefits, it deserves consideration of some disadvantages including the use of untreated wastewater for crop irrigation can also cause soil hardening and shallow groundwater contamination [45]. Therefore, Egypt started using treated domestic sewage wastewater treatment systems which will increase water recovery from wastewater and meet environmental regulatory requirements and thus protect freshwater bodies and biodiversity. SUEZ is providing Egypt with different types of sewage treatment plants including that of Gabal El As-far, on the eastern bank of the Nile [46].

Algeria - Over the past 4 decades, Algeria has experienced water stress which becomes acute due principally to high population growth rates, long periods of droughts and bad water management. The reuse of treated sewage effluent represents a valuable solution to conserve natural resources and reduce the consumption of freshwater, especially in the agricultural sector. In 2005, Algeria started using treated wastewater as alternative resources that are able to satisfy the needs of water demand in agricultural sector and promote the coordinated development of integrated water management systems [47]. At present, Algeria could indirectly improve water supply and increase water availability by reusing around 484 Hm3 of wastewater, among which only 425 Hm3 are subjected to water treatment (removes contaminants and undesirable components). The rest simply undergoes dilution in the natural environment [48].

Morocco is highly susceptible to prolonged shortages in the water supply (droughts). To reduce the impact of drought and population growth on water consumption, the Morocco government has adopted a series of legislative measures and institutional reforms to better Integrated Water Resources Management (IWRM). Since 1960s, the country has contributed significantly to the mobilization of its hydraulic capacities. Applying treated sewage effluents (TSE) in agricultural irrigation in regions suffering from water scarcity like Morocco is a non-conventional water reserve to alleviate water stress and help in saving freshwater for drinking and for improving crop productivity. Thus, a necessity for a better water resources economy, only the rate of about 12% of treated wastewater is currently recycled but this rate reached 22% in 2020 and may achieve around 100% by 2030 [49].

Tunisia is suffering from high water stress due to many contributing drivers including the region has a Mediterranean arid climate. Tunisia's water reserves are limited. Tunisia is highly vulnerable to the adverse effects of climate change (increase in temperatures and aridity with decreasing rainwater). Actually, Tunisia is determined to promote wastewater reuse and satisfy its water demand for agricultural sector and other uses and this through many ways including improving the status of existing water resources, reducing the effluent of wastewater treatment plants to the sea and raising awareness. The government policy strongly supports sewage treatment plants and incentivizes wastewater reuse. In 2009, around 63 Mm3 have been reused directly for irrigation and the total agricultural area equipped with sewage treatment plants was around 8065 hectares [50].

Libya is facing extremely high baseline water stress. With the rising population and demands for freshwater, reusing wastewater is an increasingly sustainable and acceptable practice to satisfy water needs. Thus, Libya government is increasing efforts to enhance wastewater treatment plans in order to cope with water scarcity in the region and generate sufficient water, especially in irrigation. There are about 23 wastewater treatment plants in Libya but only 10 of them are working and in operation [51].

## **5.2 Water desalination**

Seawater desalination is the process of changing seawater or brackish into usable water or pure water by which the dissolved mineral salts in water are removed. Northern African countries are suffering from water shortages for agricultural purposes and other uses. So, there are alternative potential water supply sources to meet growing water needs. Desalination is among the most sustainable alternative and extreme solutions that can solve water stress issues in Northern African countries, although it is an energy-intensive process that can be very expensive.

Egypt has the following coastlines: Northern coastal border is on the Mediterranean Sea and east coast border is on the Red Sea. This country is using seawater desalination as a major and sustainable source of water supplies and development (abundance of energy). However, this practice has been given low priority because it is affected significantly by many different factors including water quality, technical application and methods, energy-consuming, plant capacity and plant availability [52]. The capacity of desalinated water in Egypt is approximately 0.03 BCM/ year [53]. Additionally, the Egypt authority has involved both sectors (the public sector and the private one) to work together to a better agricultural water resource management through applying modern technologies for desalination such as distillation, reverse osmosis (RO) and electrodialysis.

Algeria - Desalination plants provide water that can be safe to use in irrigation. Algeria is using desalination as a viable resource during the intense time of drought. In fact, it is a great practice in Algeria as it can relieve water stress for irrigation purposes and also for other water uses for daily processes. Reverse osmosis technology is the most convenient and effective filtration method used for desalination that represents approximately around 95% [54].

Morocco - Water desalination is practically a solution for Southern Moroccan; most part of inhabitants suffers from shortages of potable water and inadequate precipitation. The following of some Southern Moroccan cities which adopt these water desalination solutions: Boujdour has used Multi-Effect Distillation and also Mechanical Vapor Compression solutions to provide a total capacity of around 250 m3 /d and Boujdour has used Sea Water Reverse Osmosis solutions to provide a total capacity of around 800 m3 /d. Laayoune has used Sea Water Reverse Osmosis solutions to provide a total capacity of 7000 m3 /d [55].

*Managing Drought and Water Stress in Northern Africa DOI: http://dx.doi.org/10.5772/intechopen.107391*

Tunisia and especially the centre and south parts of it are suffering from water scarcity and droughts periods as the low rainfall. Water desalination for irrigation seems to be a promising solution to fulfill the increased demand for freshwater. The four major desalination plants have been inaugurated to help are Kerkennah (1983) with a total desalination capacity of 3300 m3 /day; Gabes (1995) with 22,510 m3 /day; and 2 stations in Jerba-Zarzis (1999) with 12,000 m3 /day. Furthermore, there are sixties smaller plants used to help in providing water for industry uses [56].

Libya faces severe water stress problems caused mainly by the limited freshwater bodies and also drought. Water desalination is a particularly advantageous alternative freshwater source that can reduce water stress in Libya. Since the sixties, Libya has been using desalination because of its an increasingly viable alternative as it is regarded as an extreme solution for water supply. In addition, this desalination technology is widely implemented to produce freshwater over the past decades to meet the increasing demands of water for irrigation purposes and other uses. Currently, Libya has 21 operating desalination plants with a capacity of 525.680 m3 /d [57].

### **5.3 Rainwater Harvesting**

Many people in different areas of the world such as Northern Africa suffer from lack of access to safe and clean drinking water. To have access to safe potable water, huge investment costs and expenditures are needed. Roof-water or RWH is a method of collecting and conserving rainfall for future usage. The harvested water can be stored, utilized in various ways or directly used for groundwater recharge. Roofwater is an old method that has been adopted in different regions on the Earth and especially Northern African region [58]. RWH is a viable solution to help meet the growing demand for water. It can improve water productivity by collecting rainwater from impermeable surfaces (rooftops) and storing it in containers (tanks or cellars) for future uses. Additionally, RWH helps in reducing floods and soil erosion and may reduce agricultural drought risk.

Egypt – In Egypt, natural water reserves are limited. Actually, Egypt is under water stress, a problem that can be partially alleviated to meet people's needs by using RWH as good alternative to non-conventional water resources. High potential of RWH was built in Northern Egypt including Alexandria city which can help in reducing water usage home and can satisfy approximately 12 percent of its future supplementary domestic purpose. Nevertheless, in the central – south part of Egypt, the precipitation is irrelevant to be harvested [59].

Algeria - Water is naturally scarce in Algeria because of the following factors: very low rainwater, human growth considerations, droughts and thus water demand is continuously increasing. Using rainwater harvested in Algeria from houses roofs appears a great sustainable promising solution to lack of water and droughts to satisfy water needs in areas where rainfall is uneven or unequal, such as in Souk Ahras city.

Morocco has adopted fog water harvesting system-based NGO Dar Si Hmad as the most promising alternative system for sustainable freshwater resources management to minimize the shortages of water. This system is the world's largest operational fogwater harvesting system. It delivers a good solution for hundreds of rural residents who are suffering from water shortages to satisfy their basic water needs [60].

Tunisia - RWH is a solution to help reduce freshwater consumption by utilizing – rainwater from the roof. It is a satisfactory alternative practice in southeast Tunisia which suffers much from water shortage (mean annual precipitation values from 100 to 200 mm). The Tunisian authority promotes many water harvesting techniques

including surface runoff water harvesting, floodwater harvesting and spreading irrigation [4].

Libya has consistently suffered from water stress and droughts. RWH is one of the major options to provide more water. RWH is a sustainable way in Libya's coastal part that can deal with shortages of water and meet the increasing water demand (clean water).
