**3. Drought and water stress in Northern Africa**

Northern African region is characterized by considerable demographic growth. Northern Africa has hot semi-arid and arid desert climates and low rainwater. This region is predicted to face rising temperatures and decreasing rainfall. The recurrent droughts whose frequency has increased over the past 40 years can lead to water stress situations. While the overexploitation of available natural water reserves can exacerbate the consequences of droughts and thus leading to high depletion in its groundwater reserves.

## **3.1 Egypt**

Egypt's climate is extremely dry and receives a very low amount of rainwater because Egypt is predominantly desert [7]. Water resources in Egypt are limited and


### **Table 1.**

*Northern Africa's population 1960–2021 [1].*

around 98% of Egypt's water reserves originate outside of its borders. Main Egypt's freshwater reserves are the Nile River which provides the region with around 93% of its water demand, precipitation, and ground water [8]. Climate change and its effects (droughts) in Egypt are predicted to make more stress on water reserves.

Nile River - Because the rainwater in Egypt is very scarce, more than 95% of Egyptians live along the Nile or in its teeming delta for all water needs. However, the Nile River's land is threatened by climate change vulnerability which is expected to rise the frequency and intensity of floods and drought incidences in Egypt. Actually, the Nile River is predicted to decline by 40−60% of its current flow. Therefore, agricultural areas in Egypt have been subject to extensive and increasing water scarcity [9].

Rainwater – Egypt's agricultural land is concentrated in a narrow strip along the coast where more amount of rainfall, and continuously declines southward [10]. Egypt has a mild winter season in the form of scattered showers along coastal areas. The mean annual rainfall is between 0 mm in the desert to 200 mm in the north coastal region with an annual average of about 12 mm. The total amount of rainwater may reach 1.8 billion m3 per year [11]. It is predicted that the mean annual precipitation will decline not only in Egypt but also in almost Mediterranean African countries. Furthermore, changes in precipitation patterns combined with sea level rise may further lead to decline in agriculture production and cause more stress on Nile River.

Groundwater is a vital resource especially in desert areas, besides providing drinking water groundwater is used for irrigation to grow crops and also has several other purposes. Groundwater ranks as the second source of natural water resources, after the Nile and constitutes around 12% of water supplies [12]. Egypt's groundwater aquifers are considered a non-renewable resource and they are of variable importance for exploitation. The increasing demand for Egypt's water reserves has placed groundwater resources under widespread pressure subjecting it to several issues such as depletion of its water quantity and degradation of its water quality. Different human activities such as the seepage of rainwater, irrigation and drainage and other effluents commonly affect not only the quantity of groundwater resources but also its chemical water quality [13]. On the North Coast of Egypt, there is a threat of saltwater intrusion into coastal aquifers which is caused by water withdrawals from coastal aquifers and up-coming near coastal discharge/pumping wells. On the other hand, Egypt faces several serious risks from climate change that impacts almost Egypt's groundwater recharge rates and thus affects the availability of fresh groundwater (decrease in amount of precipitation and overexploitation of aquifers).

## **3.2 Algeria**

Algeria is the biggest country in Northern Africa. The southern region forms about 80 per cent of Algeria's land which is almost entirely the Sahara Desert with an arid climate. However, the northern part of Algeria's territory is less arid. More than 34% of Algerian people are living in rural areas and most of them are concentrated in coastal zone [14]. During the past century, Algeria has been subject to frequent periods of drought which has clearly led to the degradation of the water reserve (quantitative and qualitative) in northwestern and central plains. Thus, these droughts have an adverse impact on meeting the water needs of all socio-economic sectors especially agriculture; posing a significant risk to farms and leading to yield reduction.

Rainwater - Temperatures in Algeria rise during the last decades and can become more acute than expected, with an important decrease in annual rainfall, sometimes various persistent droughts. Reduced rainfall is about 18 to 27% and the dry season has increased by two months during the last century [15].

Groundwater - The rainfall deficit has resulted in a decrease in the water volumes stored in dams. This situation of insufficient freshwater to satisfy requirements and droughts events in Northern Algeria continue to cause significant risks and widespread pressure on most aquifers; resulting in groundwater-level decline which may reach around 20 m or more in certain aquifers [16].

## **3.3 Morocco**

Climate is varying considerably across Morocco's northern to southern areas. The northern coast-central areas have Mediterranean climates characterized by hot, dry summers and cool, wet winters. At high-altitude locations, the climate is humid and temperate. In the south and west parts, the climate is Saharan. Droughts are becoming more frequent and severe in Morocco and impact negatively water resources and agricultural production [17]. Mean annual temperature has increased by 0.8°C (1960–2005) [18].

Rainwater - Morocco is commonly characterized by extremely high spatial−temporal rainfall variability. The northwest part of Morocco receives more precipitation than others. The mean annual precipitation varies considerably; the relief areas can receive approximately 800 mm of rain per year. Nevertheless, the adjacent plains areas can extremely receive 300 mm of rainwater per year [19]. Due to climate variability observed over the past decades in Morocco (1960−2005), Mean annual rainfall has decreased with an amount ranging between 3% and 30%, with a drop of 26% in the north-western region of the country [18]. In fact, Morocco suffers from its worst drought over the past 40 years with low precipitation resulting in at least ~50 per cent overexploitation of aquifers.

Groundwater stretches more than 80,000 square kilometers and represents around 20% of Morocco's water reserves [20]. Morocco has ninety-six aquifers, twenty-one of which are deep and seventy-five shallows. Morocco faces its worst drought in last four decades resulting in (1) decline in rainfall, (2) decline in River flows which reached approximately 20% within the periods 1970–2006 and 1950–2006 and more than 70% in certain parts of Morocco and also (3) depletion of groundwater aquifers [21] ranging between 0.5 and 2 m per year (low groundwater recharge and over-expansion of agricultural activities) [22]. The Mikkes basin is an example of Moroccan basin. It is situated in the North-central of Morocco and had a high depletion in its water reserves: a rainfall deficit reached 76% (1970−1979 and 1980−2000); this high

rainfall deficit had led to overexploitation of Mikkes aquifers and thereby springs and River flows depletion [23–27]. Furthermore, Morocco's aquifers groundwater quality assessment shows a deterioration, as a result of combined pressures of climate change (seawater intrusion) and human activities (nitrate pollution).

## **3.4 Tunisia**

Tunisia is situated between Algeria (on the west and southwest) and Libya on the southeast (**Figure 1**). Tunisia's climate varies with location: The north region is with a sub-humid to semi-arid climate. The central part is with semi-arid to arid climate and the southern part has a desert climate. Tunisia is vulnerable to climate change resulting rise in temperature, a reduction in rainwater and sea level rise. Over the past decades, temperature increased by approximately 0.4°C per decade. In southern Tunisia, droughts become increasingly more intense and frequent, while Tunisia's Mediterranean coast has been treated with rising sea level and flooding [28]. Between 1900 and 2000, the mean annual temperature increased by around 1.4°C [29].

Rainwater - As Tunisia is bound on the northeast by the Mediterranean Sea, on the south - the southwest by the Sahara (**Figure 1**), the precipitation is variable from the north to south and from east to west. Northern Tunisia is the rainiest part as mean annual rainfall reaches more than 400 mm in the extreme north and 1500 mm in the extreme northwest. However, the centre of Tunisia has average precipitation ranging between 150 and 300 mm [30]. The Tunisian southeast is characterized by an arid Mediterranean climate, with average precipitation varying between 100 and 200 mm per year [31]. Actually, precipitation amounts have changed in Tunisia during the 20th century and the region has experienced several severe droughts. Since the fifties, the annual totals of precipitation have declined by 0.5% per year in northern Tunisia [32].

Groundwater - As Tunisia has been suffering from increased recurrent and frequent droughts which led to high rainwater decline. Many farms rely on wells (groundwater) to fulfil their water needs. This will most likely extend to the over-use of groundwater resources where many aquifers are already experienced; putting more pressure on groundwater means that the rate of pumping is greater than the rate of infiltration. Consequently, the level of certain aquifers drops so much and thus many wells run dry. Actually, by 2030, the overexploitation of Tunisian coastal aquifer (due to agricultural activities) will drop from 28% [33] and 50% of coastal aquifers and will be salinized due to sea-level rise [34]. Therefore, this country needs urgent and practices approaches for better water management to avoid more water reserve deteriorations.

## **3.5 Libya**

Libya is a country located in North Africa and it is the fourth-largest one in all African continents (**Figure 2**). About 95% of Libya consists of desert (the Sahara) and under 2% of the land is arable. Libya has two distinct climates: One in the south is characterized by hot arid Sahara climate and the other is influenced by the Mediterranean Sea resulting moderated climate. Climate change has many effects including rising temperatures and more severe frequent droughts and floods. The limited natural resources (water and soils), the desert lands and the drought events are all the main drivers which will force Libyan farmers to abandon their farms amidst water stress and therefore the yields of rainfed agriculture will be severely low.

Rainwater - Libya is one of the driest regions on Earth with no permanent rivers flowing through its boundaries. About 96% of Libyan land surface receives annual precipitation which cannot reach an amount of 100 mm. Less than 2% of the Libya region receives enough rain to support agriculture, and only a narrow ribbon along the coast receives more than 100 mm of rain per year. Furthermore, the effects of global climate change in Libya include more rising in temperatures, a drop in precipitation amount which is already very low and prolonged period of droughts which will produce increased aridity. For the 66 years (1945−2010), temperature data in Libya showing that the mean annual temperature has risen [35].

Groundwater freshwater reserves in Libya originate from 4 aquifers: Kufra, Sirt, Morzuk and Hamada that provides over 90% of Libya's water. These aquifers are likely to be even more important as drought increases and rainfall decreases. Increase in drought tendency is a principal factor in lack of rainwater (or water availability). This water scarcity is expected to cause more aquifers depletion (quantitative and qualitative) in the region. The intensive extraction of groundwater (GW) in coastal aquifers is causing a reduction in the availability of freshwater outflow to the sea and creates local water table depression, causing saltwater intrusion [36], resulting in deterioration in groundwater quality.
