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Home The River Basin People and the River Governance Resource Management
The River Basin
 Introduction
Geography
Climate and Weather
Hydrology
Water Quality
Ecology & Biodiversity
 Ecology
 Aquatic Ecology
 Wetlands
Function of Wetlands
 Biodiversity
Watersheds
 References

 



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Function of Wetlands  

The water and wetland resources of the Kunene River, provide numerous socio-economic development benefits to the riparian states, including among others:

  • Groundwater Recharge;
  • Water Quality;
  • Flow Regulation;
  • Plant and Animal Products;
  • Erosion Control & Flood Plain Farming;
  • International Recognition for Conservation; and
  • Tourism & Recreation.

Therefore, careful and appropriate management is important to sustain the various sectors of the economy that depend on wetlands and their effect on water resources.

In addition to socio-economic benefits, wetlands can provide significant biophysical benefits, including groundwater recharge and improved water quality.

Groundwater Recharge

Depending on the soil, geology, and landscape of a wetland ecosystem, wetlands can contribute to groundwater recharge if water can percolate to the groundwater system. This function of wetlands can be very important where communities rely on groundwater resources for drinking water. Due to their storage capacity, wetlands often retain water during wet periods and release water during periods of drought, contributing to stream flow during these dry periods. See below for a conceptual diagram of the groundwater component of the water cycle.

Role of Groundwater in the Hydrologic Cycle.
Source: CSIR 2004
( click to enlarge )

Water Quality

Wetlands play an important role in improving surface water quality by filtering suspended material (e.g. organic or inorganic sediments) and by retaining nutrients and pollutants. Both physical and chemical processes are important for this to happen.

Wetland vegetation can help trap suspended material, and the slower-moving or static waters in wetlands allow suspended particles (and any adsorbed chemicals) to settle. Nutrients dissolved in water inflows can be used as resources by aquatic organisms or vegetation within the wetland, and can, along with pollutants and other chemicals, be chemically altered, stored within plants, or attached to wetland sediments.

The benefits of water quality improvement to downstream ecosystems can include the prevention of eutrophication, removal of water-borne pathogens and toxic chemicals, and protection of fish health and navigation routes as the load and deposition of suspended sediments is reduced. However, the processes responsible for water quality improvement can themselves be degraded by water pollution, depending on the specific characteristics of the soil, vegetation, and aquatic organisms and the nature of the water inflows (Hatfield Consultants 2006).

The water of the Kunene River is of good quality with an annual discharge at Ruacana of approximately 5 000 Mm³ (Burmeister&Partners 1998).

Flow Regulation

Besides serving as the sources for many streams, wetlands also regulate flow and attenuate floods. Flood-plains store water during the wet seasons, slowly releasing it throughout dry periods. This helps to maintain flow in the perennial rivers of the basin and in some of their tributaries. This function of wetlands depends on a number of parameters: the size and shape of the wetland, number of wetlands located in a particular sub-basin or the entire basin, soil type and depth, and the vegetation in the wetland.

Plant and Animal Products

The nutrients in the wetland environment of the basin support diverse plant and animal species. Wetlands are principal habitats for fish species, providing cover as well as suitable breeding and feeding grounds. Fish surveys between 1994 and 2004 (HAY et al 2008) identify 50 fish species in the lower Kunene including 5 endemic species. Other studies mention 68 species (Burmeister&Partner 1998) and 77 species (Okeyo, 2000). Families with the highest numbers of species are Cyprinidae (14) and Cichlidae (12). The four most important species are Schilbe intermedius, Brycinus lateralis, Barbus mattozi and Labeo ansorgii. The Kunene River mouth is one of the very few areas of sheltered shallow water along the arid Atlantic coastline, and it sustains important numbers of water birds and mammals.

Fisherman and his day's catch.
Source: Tump 2007
( click to enlarge )

Erosion Control and Flood Plain Farming

Plants in marshes and swamps hold the soil and trap sediments in their roots. Wetlands therefore play an important role in flood control and erosion prevention. Well-vegetated rivers and floodplains are excellent flood wave absorbers. The deposited sediments and the variations in flooding create fertile soils that can be used to support subsistence floodplain farming.

International Recognition for Conservation

The rich biodiversity and natural beauty of wetlands make them an important focus for conservation. Etosha Pan to the south of Kunene watershed is included in the list of wetlands of international importance of the Ramsar convention.

Tourism and Recreation

Due to their natural beauty and richness in biodiversity wetlands provide potential for recreation and generation of benefits through tourism. Tourism is not yet well developed in Angola. Only few tourists reach the Kunene River basin by visiting the Kaokoveld area in Skeleton Coast National Park from the Namibian side. The main draw for tourists in the area is the Etosha Pan. This wetland lies in close vicinity to the Kunene River basin. Main attractions are game viewing and enjoying the impressive landscapes with its air of solitude and isolation.

 

 



Interactive

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Video Interviews about the integrated and transboundary management of the Kunene River basin


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