1.1.1.WATER RESOURCES The Republic of the Congo has a dense river network organized around two major river basins: the Congo River Basin, which occupies about 72 per cent of the total land area, and the Kouilou-Niari, covering about 16 per cent. To these two basins must be added the smaller coastal basins: the basins of the Loémé, high Nyanga, Upper Ogooué, and Chilango. Groundwater is also abundant. It is supplied by four main aquifers: •the aquifer of the coastal sedimentary basin (6,000km2); •the aquifer of the sedimentary basin of the Congo (224,000km2); •a series of ancient sedimentary aquifers (68,000km2); •crystalline and crystallophyllian rock aquifers (44,000km2). The first two hydrogeological units contain more or less porous and permeable sediments. These lands cover 67 per cent of the national territory and aquifers are widespread. The other two hydrogeological units occupy 33 per cent of the country. They represent the discontinuous base aquifers, dominated by crack porosity. The Republic of the Congo has two dams, the Djoué and the Moukoukoulou, with a total capacity of 9 million m3. Around 20 per cent of Congolese territory is composed of wetlands, including inundated forests and savannas and coastal areas occupied by mangroves. These areas are essential for the conservation of biodiversity and play a major role in regulating the flow of the Congo river and coastal watersheds. Renewable water resources are very abundant. Internal renewable water resources are estimated at 222km3/year. Taking into account the water coming from neighbouring countries and the water boundary between countries, they amount to 832km3/year.

1.1.2.WATER USE Water withdrawals are made to satisfy domestic, industrial and agricultural demands. They include 32 million m3/year for domestic use (69 per cent), 10 million m3/year for industry (22 per cent) and 4 million m3/year for agriculture (9 per cent). Overall, they total 46 million m3/year. Projections for 2025, drawn up as part of an analysis of the situation of central African countries in terms of resource management, show that the water needs for the population will be 312 million m3, about 10 times current use.

1.2.WATER QUALITY, ECOSYSTEMS AND HUMAN HEALTH Overall, surface water in the Congo is poorly mineralized and falls into the category of fresh water (i.e. total mineralization is below 100mg/L), as do the four major groundwater aquifers. Only a few formations of shale and limestone series, located in the departments of Bouenza and Niari, have total mineralization above 100mg/L. Although unsuitable for human consumption because of their hardness, these waters, to some extent, can be used for irrigation and watering livestock. The composition of the chemicals dissolved and suspended in surface water does not indicate excessive levels of undesirable elements. The material balance shows values between 8 and 20 tons/km3/year of dissolved solids, which is not an obstacle to the agricultural use of these waters. Access to water of acceptable quality is 58 per cent nationally, and access to improved latrines is estimated at 7 per cent in urban areas and 2 per cent in rural areas. Many health centres and primary schools do not have access to clean water and sanitation. The consequence is a high degree of water-borne diseases such as diarrhoea and parasitic and skin diseases. UNICEF is developing door-to-door sensitization campaigns concerning water treatment, aimed at strengthening households’ capacities to disinfect houses and treat borehole water. UNICEF has also supported the increase in the chlorine content of the piped water system. All of these interventions prevented the further spread of disease (UNICEF, 2008).

(Water Risk Filter)