Green Hills, Blue Cities

URBANWATERRESOURCES MANAGEMENTCHALLENGES: THECASEOFYAOUNDÈ

Ayonghe N. Samuel, Fantong Y. Wilson and Fouépé T. Alain

Yaoundé is located 250 km from the Atlantic coast and lies at the edge of the Congo Forest. Covering an area of about 300 km 2 (Nguegang 2008) Yaoundé has been the political capital of Cameroon since 1921 and also serves as the headquarters of the Centre Region.

Yaoundé and its surrounding area comprise mainly of secondary forest although much has been deforested for crop

farming. In the swampy depressions semi-aquatic plants such as raphia and palm trees are found (Boeglin and others 2003).

The relief in Yaoundé is undulating with seven outstanding hills that rise to a maximum of 1 060 m above sea level. The city’s average altitude is 700–800 m above sea level and the climate is characterised by annual precipitation of 1 600 mm, average temperature of 24°C and evaporation of 800 mm per year (Sighomnou 2004). Yaoundé experiences four climatic regimes – a long dry season (from mid-November to mid-March), a short rainy season (from mid-March to mid-June), a short dry season (from mid-June to mid-September), and a long raining season (from mid-September to mid-November). The geology of the city is made up of crystalline rocks composed of granite, gneiss and schist rocks, which are highly weathered, producing predominantly ferric and lateritic soils. These chemically weathered soils serve as aquifers for shallow groundwater, while fractured rocks and more extensive faulted areas are locations for deep groundwater. Spring lines are located at the base of slopes and in wetlands, serving as sources of water for domestic use and subsistence agriculture during the dry periods (Fouépé and others 2010). The city and its environs are drained by a dense river network, which can broadly be divided into two major drainage basins, namely the Sanaga River to the north-west and Nyong River to the south-east. Pipe-borne water in the city is supplied from the Nyong River from which it is withdrawn at Mbalmayo, 45 km south-east of Yaoundé, and conveyed by a 1 400 mm diameter pipe to the city.

Lake Chad

CHAD

Maroua

NIGERIA

Garoua

Ngaoundéré

Bamenda

CENTRAL AFRICAN REPUBLIC

Bafoussam

Bertoua

Buea Douala

Yaoundé

Ebolowa

EQUATORIAL GUINEA

REPUBLIC OF THE CONGO

GABON

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