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The Mediterranean coast

The Mediterranean Coast extends from Morocco in the west to Egypt in the east and is the aggregation of a large quantity of small, independent coastal basins draining to the sea. Its total area represents 2.2% of the area of the continent and spreads over five countries (Map 14 and Table 54).

TABLE 54 Mediterranean Coast: areas and rainfall by country

Country

Total area of the country (km)

Area of the country within the basin (km)

As % of total area of basin (%)

As % of total area of country (%)

Average annual rainfall in the basin area (mm)






min.

max.

mean

Morocco

446500

108300

15.9

24.3

185

740

350

Algeria

2381740

133327

19.6

5.6

270

895

495

Tunisia

163610

85162

12.5

52.1

60

735

300

Libya

1759540

287168

42.3

16.3

5

430

90

Egypt

1001450

65568

9.6

6.5

60

140

100

For Mediter. Coast


679525

100.0


5

895

235

Rivers and discharges

The total renewable water resources for the different basins and regions in the Mediterranean Coast in Morocco are summarized in Table 55.

TABLE 55 Renewable water resources by basin of the Mediterranean Coast in Morocco

Basin/region

Renewable surface water (km/year)

Renewable groundwater (km/year)

Total renewable water (km/year)

Moulouya

1.30

0.70

2.00

Loukkos

1.60

0.03

1.63

Other

2.85

0.40

3.25

Total

5.75

1.13

6.88

For Algeria a study has been done on the water availability and needs for 2025 by basin, as explained in the section The North Interior. Table 56 summarizes the figures for the eight basins of the Mediterranean coastal part of Algeria [50].

TABLE 56 Estimated water balance in the Mediterranean Coast in Algeria in 2025 [50]

(in km/year)

2025

Water availability:


Total surface water

12.050

Available surface water

4.454

Groundwater

1.391

Water re-use

1.616

Total available water

7.461

Water demands:


Irrigation

2.695

Other water uses

3.691

Total water use

6.386

Balance

1.075

The Medjerda River in Tunisia is the country's major perennial stream. Flows fluctuate greatly with quantities in June and July amounting to less than one-twelfth of those in February. The available renewable water resources in the Mediterranean Coast in Tunisia are estimated at about 2.60 km/year, of which 1.95 km is surface water and 0.65 km is groundwater (see also the section The North Interior).

The renewable water resources for Libya are estimated at 0.6 km/year. Information on the renewable water resources of Egypt in this area is not available.

Irrigation potential, and water requirements

The irrigation potential in the Mediterranean Coast in Morocco has been estimated at 380000 ha [150, *]. The irrigation water requirement is about 9000 m/ha per year [*]. The country estimates that its water use, at present 13375 m/ha per year, will be 10380 m/ha per year in 2020 [149].

In Algeria, the irrigation water requirement has been estimated at 7000 m/ha per year [49]. The present study considers an irrigation water requirement of 9000 m/ha per year for the Mediterranean Coast. The irrigation potential using renewable water ranges from a minimum of 243150 ha, considering a water use of 9000 m/ha per year and a water availability of 2.188 km/year, to a maximum of 385100 ha, considering a water use of 7000 m /ha per year and a water availability of 2.695 km/year. The low estimate on water availability is based on the assumption that for the basins where the water balance is negative (three out eight with a total deficit of 0.507 km/year) this quantity is deducted from the water available for irrigation [*].

The irrigation potential for the whole of Tunisia has been estimated at 563000 ha, of which about 523000 ha are in the Mediterranean Coast [204]. With an irrigation water requirement of 11000 m/ha per year [*], this would require in total 5.75 km/year of water, which greatly exceeds the available water resources, estimated at 2.60 km /year. A reduced area of 189000 ha would require 2.08 km/year of water. The 523000 ha could only be irrigated using 4000 m/ha per year of water.

In Libya about 40000 ha could be irrigated with renewable water [*], the remaining part of the potential, estimated at 460000 ha in the Mediterranean Coast would have to be irrigated by fossil water [131]. This is part of the Great Man Made River Project, where fossil water is transferred from the North Interior to the Mediterranean Coast.

The irrigation potential in Egypt has been estimated at 60000 ha, almost all using fossil water [*].

Table 57: Mediterranean Coast: irrigation potential, water requirements and areas under irrigation

Country with an area within the North Interior

Irrigation potential using renewable water (ha)

Gross irrigation water requirement (m/ha.year)

Total irrigation water req. (km/year)

Irrigation potential using fossil water (ha)

Gross irrigation water requirement (m/ha.year)

Total irrigation water req. (km/year)

Area already under irrigation (ha)

Morocco

380000

9000

3.420




248200

Algeria (1)

385 100

7 000-9 000

2.696




500

Tunisia (2)

523 000

4 000-11 000





360000

Libya

40000

12500

0.500

460000

8900

4.094

320000

Egypt




60000

13 000

0.780

168 000

Sum of countries

1328100


8.696

520000


4.874

1 606 700

For Mediter Coast

< 850000







(1) Considering 2.695 km/year of water available for irrigation and using 7000 m/ha per year: irrigation potential 385100 ha.

Considering 2.188 km/year of water available for irrigation and using 9000 m/ha per year: irrigation potential 240000 ha.

(2) Available renewable water: 2.080 km/year: irrigation potential 523000 ha if using 4000 m/ha per year and 190000 ha if using 11000 m/ha per year.

850000 ha is the sum of: 380000 (Morocco) + 240000 (Algeria) + 190000 (Tunisia) + 40000 (Libya).

Depending on the irrigation water requirements, estimates of the irrigation potential in the Mediterranean Coast, based on renewable water resources, range from 850000 ha to 1291100 ha.

The North West Coast

The North West Coast covers 2.2% of the continent and spreads over three countries (Map 15 and Table 58).

Table 58: North West Coast: areas and rainfall by country

Country

Total area of the country (km2)

Area of the country within the basin (km2)

As % Of total area of basin (%)

As % of total area of country (%)

Average annual rainfall in the basin area
(mm)






min.

max.

mean

Morocco + W.Sah.

712 500

449 518

67.0

63.1

6

680

150

Mauritania

1 025520

204 385

30.5

19.9

20

310

95

Algeria

2 381 740

16 718

2.5

0.7

0

110

60

For N.West Coast


670 621

100.0


0

680

145

Rivers and discharges

The total renewable water resources for the different basins and regions in the North West Coast in Morocco are summarized in Table 59.

No information on renewable water resources is available for the Western Sahara, Mauritania OR Algeria.

Table 59: Renewable water resources by basin of the North West Coast in Morocco

Basin/region

Renewable surface water (km/year)

Renewable groundwater (km/year)

Total renewable water (km/year)

Sebou

6.60

2.90

9.50

Oum er Rbia

4.50

1.50

6.00

Souss-Massa

0.48

0.29

0.77

Draa

0.77

0.10

0.87

Other

3.59

1.43

5.02

Total

15.94

6.22

22.16

Irrigation potential and water requirements

The irrigation potential in the North West Coast in Morocco has been estimated at 1200000 ha [15]. The present study estimates the gross irrigation water requirement at 9000 m/ha per year in the northern part and 15000 m/ha per year in the southern part. The country estimates that its water use, at present 13375 m/ha per year, will be 10380 m/ha per year in 2020. No data are available on the Western Sahara.

Table 60: North West Coast: irrigation potential, water requirements and areas under irrigation

Country

Irrigation potential (ha)

Gross potential irrigation water requirement

Area under irrigation (ha)



per ha
(m3/ha per year)

total (km3/year)


Morocco + W.Sah.

1 200000

9 000 - 15 000

12.000

1 000000

Mauritania

0

17500

0.000

750

Algeria

0

14 500

0.000

0

Sum of countries

1 200000


12.000

1 000 750

Total for Limpopo

<=1200000


12.000


For Mauritania the only potential is some 750 ha of oases [145]. Less than 1% of the total area of Algeria is located in the North West Coast. The irrigation potential in this area is estimated to be negligible.


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