Molopo

The Molopo wetland in the North West Province is an internationally unique high altitude peatland that began forming after the last ice age, 11,000 years ago,.  The wetland is home to at least one endemic fish species, and provides livelihoods benefits to the nearby community in the form of water, fish and wetland plants.   

It is characterised by sedges and reeds and lies in a dolomite-driven system on the Highveld.  It plays a significant role in improving water quality, not least because of its deep peat deposits.  Peat is an organic-rich soil that forms in wetlands under saturated, anaerobic conditions.  It is the first stage in the formation of coal, and an important store of carbon.  Carbon in the semi-decomposed organic matter that makes up the soil acts as a highly effective filter.  Peat enhances the ability of wetlands to remove toxicants, improve water quality and store water.  

Increasing demand for water for agriculture and urban development has placed enormous pressures on the dolomitic systems of the Highveld.  Water diversion and abstraction reduces water availability downstream, in many cases resulting in degradation of wetlands and loss of wetland habitat.  This threatens the many endemic and endangered species dependent on wetland ecosystems.  The Molopo wetland is also threatened by sand mining, which contributes to severe soil erosion in the wetland and its catchment. Agriculture in its catchment results in high nutrient and toxicant loads entering the system, and the flow patterns of water entering the wetland have been altered by dams and cultivated fields. Dams also reduce the sediment load in the water flowing into the wetland, which results in erosion of the wetland.  

The wetland was modified by drainage channels and canalisation, which has resulted in desiccation of a large section.  In turn, this has resulted in encroachment of terrestrial and invasive alien plant species, which further dries out the wetland and exacerbates erosion.  Overgrazing is a significant impact.

A number of concrete structures will be built to arrest erosion and improve the wetland’s ability to provide habitat for biodiversity and improve water quality.  Once in a healthy condition, it is expected that the wetland and its resources could be used for tourism, crafts and crops.  Grazing will need to be monitored and managed more effectively.  

Working for Wetlands has been active in the Molopo catchment since 2001, with previous work focusing on wetlands near Mafikeng and Rooigrond.  Current work is focused on the headwaters of the Molopo river and the area between the Monshioa and Disaneng dams. The 2008/9 project budget is R 2,074,000, and the project provides temporary employment and skills development for 44 people.  

Molopo Wetland 1 : This 175 ha wetland is used for subsistence grazing, and land use in its catchment includes agriculture and residences.  An incised channel in the wetland results in drainage of the wetland and erosive, high flow water velocity through the channel. Overgrazing has reduced vegetation cover, and a dam upstream has changed the natural flow regime, which results in the wetland drying out during low flow periods.  When the dam releases water, flow is fast immediately below the dam wall, and about 4 m above the original stream level.  However, existing concrete structures control erosion in the section of high flow velocity, and there is continuous monitoring to ensure that erosion features do not develop.  A grove of invasive alien Mesquite trees in a tributary about 3 km upstream of the dam wall threatens biodiversity.  Rehabilitation intervention is aimed at restoring the original hydrology of the wetland.  Concrete structures are used to block the main erosion channels and arrest erosion in the smaller channels.  The water table will be raised to 0.5 m below ground level to maintain normal flow within the channels, and thereby reduce flood impacts.  This will also allow for rewetting of the desiccated sections of the wetland and lead to improve vegetation cover.  Invasive alien plant species will be removed.  

During the planning and consultation stage, residents raised concerns that children and livestock could fall into pools created by rehabilitation structures.  However, it was evident that the erosion channels pose similar threats in their unrehabilitated state. 

Contacts

For more detailed information such as project implementation plans and progress reports, please visit www.thelapa.com, click on Working for Wetlands and enter view for both username and password.