The Densu River Basin has an area of 2,490 km2 and spans 11 Local Government Assemblies in three regions (i.e. Central Region, Eastern Region and the Greater Accra Region). There are about 200 settlements in the Basin and the total population is over 600,000, equivalent to 240 persons per km2. This figure is visibly far higher than the national average of about 100 persons per km2.
The main occupation is agriculture, which engages about 40% of the economically active population. The vegetation consists of coastal savannah, thicket and grassland in the south, and moist semi-deciduous forest in the north. The river takes its source from the Atewa Range near Kibi and flows for 116 km into the Weija Reservoir before entering the Gulf of Guinea through the Densu Delta Ramsar Site. The mean annual runoff is 500x106 m3. The Densu River is of specific importance since it includes the Weija Reservoir which supplies water for approximately half of the Accra Metropolitan Area.
The Densu Basin is located at the South Eastern part of Ghana and lies within longitudes 10 30'W -10 45'W and latitudes 50 45'N - 60 15'N. It shares its catchment boundary with the Odaw and Volta Basins to the east and north, the Birim in the northwest and the Ayensu and Okrudu in the west. The map below gives a clearer picture of the location of the Basin
From the source to the Gulf of Guinea, the Densu River traverses upper Birimian rocks (phylites, schists, tuffs and grey wackes) in the upper reaches, middle Birimian rocks (grinites and granodiorites) in the middle segments and Togo series (quartzites , shale and phyllites) in the lower portions. The Densu Basin is generally low lying with undulating topography and isolated ridges forming the characteristic landscape features in many places.
The soils are mainly well drained, friable, porous, loamy savanna ochrosols mostly red or reddish brown in colour. They are generally low in nutrients especially phosphorus and nitrogen. In the northern parts of the Basin are forest Ochrosol, red or reddish brown, orange brown or brown in colour with adequate amount of nutrients.
Fuelwood provide the main energy resource. It is harvested and used directly or processed into charcoal before use.
WILDLIFE AND FISHERIES
Animals such as deer, African python, alligators, antelopes and crocodiles used to be common in the Basin but all are now extinct. These animal species have been replaced by grasscutters and rats.
There are about 18 fish species in the Densu including the Weija Reservoir. However, the most commonly fished species are Tilapia and Mud-fish.
From the onset of the pioneering programme, much effort was devoted to creating a suitable basin-based management structure. The institutional framework, which by early 2004 officially became established, centered on establishing the following entities: (i) WRC Densu Basin Secretariat, (ii) the Densu Basin Board (which administratively is established as a WRC sub-committee) and the establishment of links with the Local Government Assemblies.
The following are some baseline studies that have been carried out in the Densu Basin:
Water Resources Management Study of the Coastal River Systems in Ghana, May, 1998
Water Resources Management Problems Identification, Analysis and Prioritization Study, September, 2000
Rapid Environment Assessment of the Densu River Basin, July, 2001
Identification of Major Trends in the Socio-economic Development in the Basin of Relevance for IWRM and Compilation of Participatory Methods of Relevance for IWRM in the Densu Basin, February, 2003
Groundwater Assessment of the Densu Basin, July, 2003
Training Needs Assessment of Stakeholders in the Densu Basin and Vegetation Cover Survey, October, 2004
Towards Establishing of an IWRM Structure for the Densu Basin, June, 2004.
Recommendations from these baseline studies informed the first selection and setting up of the Densu Basin Management structure and the institution of the initial interventions made with respect to the introduction of IWRM in the Densu Basin.
Some of the problems that threaten the ecological integrity of the Densu River Basin that were noted by the baseline studies and study tours are:
Indiscriminate harvesting of wood from the micro-catchments of the river
Agriculture (food crops and rearing of animals) on the banks of the river
Use of agrochemicals in farming and harmful chemicals in fishing
Infrastructure development including the siting of industries at unauthorized locations
Inappropriate disposal of solid waste and liquid waste from the Local Government Assemblies, farms, domestic and industrial sources into the river
Mining including sand winning and quarrying in and around the Basin
Culture that engenders poor, polluting and unchanging attitudes of communities.
Activities that have been embarked upon to restore the ecological integrity of the Basin, that are still being sustained are as follows:
Awareness creation, education and training of stakeholders through radio and television programmes, newspaper articles/communiqué, community durbars, seminars, workshops and consultations to induce understanding and change of attitudes
Provision of information to students for their theses and consultants working on various Densu Basin-based assignments.
Collaboration with key stakeholder institutions such as the Environmental Protection Agency, the Local Government Assemblies, Fisheries Commission, Forestry Commission, Minerals Commission the Ghana Water Company Limited and the Community Water and Sanitation Agency among others; to:
carry out field operations to control pollution
check illegal mining activities
dredge sections of the river to curb flooding where necessary execute basin-wide projects or micro projects such as the Urban Catchment Management Project which was implemented within the Weija micro-catchment, under the Water for African Cities Programme with support from the UN-HABITAT, Nairobi – Kenya
assist with the identification and registration of major water users and well drillers within the Basin
Running of ecological monitoring (3 times/year) and water quality monitoring (5 times/year) with Board members to have contemporary knowledge about ecological trends within the Basin
Organization of quarterly Board meetings to strategize and institute interventions to ensure the sustainability and development of the Basin.
So far, the following outline represents the achievements in implementing IWRM in the Densu Basin:
An Integrated Water Resources Management Plan for the Densu Basin has been developed that informs the drawing up of annual work programmes
Various entities are growing plants to serve as vegetative cover to protect the Basin against erosion and siltation as a result of intensified and sustained awareness creation
Water quality within the Basin is improving partly due to improving sanitation and changing attitudes within the Basin
Sections of the midstream of the Basin has been dredged to curb flooding
Over fifty licensed well drillers and raw water users are complying with the Water Use Regulations (L.I. 1692 of 2001) and the Drilling Licence and Groundwater Development Regulations (L. I. 1827 of 2006) of the Water Resources Commission, which is contributing to the environmental quality of the Basin.
Efforts that are being made in the Densu River Basin are being replicated in the White Volta, Ankobra, Pra and the Tano Basins. It is expected that all the vital water bodies of Ghana would be covered as managed aquatic ecosystems by the Water Resources Commission in the near future.