Welcome to Water Resources Commission

Ghana is well endowed with water resources, but the amount of water available changes markedly from season to season as well as from year to year. Also the distribution within the country is far from uniform with the south-western part better watered than the coastal and northern regions. However, availability of water is decreasing owing to rainfall variability (climate change), rapid population growth, increased environmental degradation, pollution of rivers and draining of wetlands. All of Ghana's rivers drain southwards to the Gulf of Guinea. The Volta River, with a catchment area within Ghana of nearly 70% of the country, is by far the largest river draining the entire north, centre and east of the country. The remaining rivers, all in the south and southwest, drain about 30% of the country.

The major sub-basins of the Volta include the Black and White Volta Rivers, the Oti River and the Lower Volta, including Lake Volta. The South-Western Rivers System comprises the Bia, Tano, Ankobra and Pra Rivers, while the Coastal Rivers System is made up of Ochi-Amissah, Ochi-Nakwa, Ayensu, Densu and Tordzie/Aka Rivers.

The Volta River basin is shared with Cote d’Ivoire, Burkina Faso, Togo, Benin and Mali. The Bia is shared with Cote d’Ivoire, while the lower reaches of the Tano River also form part of the boundary with Cote d’Ivoire.

Impoundments and reservoirs have been constructed for hydropower generation, water supply and irrigation. At Akosombo, 100 km from the mouth of the Volta, the first Volta hydroelectric dam was constructed in 1964, which has created one of the largest man-made lakes in the world, covering an area of about 8,300 km2. A smaller impoundment, the Kpong Headpond, covering an area of about 40 km2, was completed in 1981, when another hydroelectric scheme was commissioned at Kpong, 20 km downstream of Akosombo. Other important impoundments are the Weija and Owabi Reservoirs on the Rivers Densu and Offin, respectively. In addition to these, the only significant natural freshwater lake in Ghana is the meteoritic crater lake, Lake Bosumtwi.

Surface water quality considerations are becoming increasingly important due to mining activities, urban and industrial pollution problems and agricultural development. Reliable data on water quality is of importance for proper management and thereby the protection and development of surface water resources for the future. A further important ongoing concern requiring appropriate hydrological data is the current and future development of urban drainage in a number of Ghana's major cities, for which flood and storm runoff data is needed for proper planning and design.

The occurrence of groundwater in Ghana is associated with 3 main geological formations. These are the basement complex, comprising crystalline igneous and metamorphic rocks; the consolidated sedimentary formations underlying the Volta basin (including the limestone horizon); and the mesozoic and cenozoic sedimentary rocks. The basement complex and the Voltain formation cover 54 percent and 45 percent of the country respectively. The remaining 1 percent consists of mesozoic and cenozoic sediments.

Groundwater occurrence in the basement complex is associated with the development of secondary porosity as a result of jointing, shearing, fracturing and weathering. The depths of aquifers are normally between 10 m and 60 m, and yields rarely exceed 6 m3/hr. In the mesozoic and cenozoic formations occurring in the extreme south eastern and western part of the country, the aquifer depths vary from 6 m to 120 m. There are also limestone aquifers, some of which are 120 m to 300 m in depth. The average yield in the limestone aquifers is as high as 180 m3/hr.

The quality of groundwater resources in Ghana is generally good except for some cases of localised pollution and areas with high levels of iron, fluoride and other minerals. Salinity in certain groundwater occurrences is also found especially in some coastal aquifers.

The major consumptive uses in Ghana are water supply, irrigation and livestock watering. Domestic and industrial urban water supplies are based almost entirely on surface water, either impounded behind small dams or diverted by weirs in rivers. Water supplies in rural areas, however, are obtained almost exclusively from groundwater sources. The various groundwater development programmes have resulted in the establishment of more than 10,000 boreholes countrywide. At present irrigation development does not play an important role in the overall water resources balance considerations. However, the potential for irrigation has been shown to be considerably larger than the present land area being irrigated. The main non-consumptive uses are hydropower generation, inland fisheries and water navigation.

On the basis of surface water resources alone, the consumptive water demand for 2020 has been projected to be 5.13 billion m3, which is 13 percent of the surface water resources. Likewise, the non-consumptive demand can also be met from the surface water available. Rainwater harvesting has also become common and has a great potential to increase water availability in certain localised areas. It can be concluded, that if properly conserved and distributed, the surface water resources of the country should be adequate to meet future demands