NFEPA Atlas 5.3_20111025_FINAL.indd - Biodiversity GIS - SANBI

3.3 Free-flowing riversA free-flowing river is a long stretch of river that has not been dammed. A freeflowingriver flows undisturbed from its source to the confluence with another largeriver or to the sea. Today there are very few large rivers that remain undammed,or ‘free flowing’. Free-flowing rivers are rare features in our landscape and animportant part of our natural heritage. They offer considerable social, economicand conservation value, supporting the livelihoods of people in the catchment. Poorrural populations with close livelihood links to the river are likely to be impactedmost and benefit least from dams. As discussed in Section 1.2, water flowing out tosea is not wasted but plays an important role in securing a range of estuarine andmarine ecosystem services.Opportunities for conserving free-flowing rivers are fast disappearing with thegrowing demand for development of water resources. While acknowledging theimportance of developing water resources, there is also an urgent need to identifysome free-flowing rivers that can serve as a representative set of our country’s lastremaining free-flowing rivers, and to maintain their free-flowing character.Free-flowing rivers are rivers withoutdams – a rare feature in the South Africanlandscape. Dams prevent water from flowingdown the river and disrupt ecologicalfunctioning with serious knock-on effectsfor the downstream river reaches and users.Nineteen flagship free-flowing rivers havebeen identified. Their free-flowing charactershould be maintained and they shouldremain in a good condition in order toconserve a representative sample of ourheritage.Table 3.1: Free-flowing rivers of South Africa. River names in blue are flagship free-flowingrivers that are top priorities for retaining their free-flowing character. Rivers arelisted from west to east.Eastern CapeRietKapMpekweniMgwalanaKobonqabaiNxaxoQhorha & tributaries*ShixiniNqabarha*NtlonyaneXora*MncwasaMdumbiMtakatye*MnenuSinangwanaMngazanaMntafufuMzintlavaMkoziMsikaba*Mtentu*SikombeMpahlaneMzamba*Mtamvuna & tributaries*Kraai & tributaries** Free-flowing rivers longer than 100 kmKwaZulu-NatalMzimkhulu*MzumbeMpambanyoni*aMahlongwaaMahlongwanaMkomazi & tributaries*Nsuze* (tributary of Thukela)Matigulu & tributaries*Black Mfolozi & tributaries*NsongeNondweniNgogoMfule*Nyalazi*Mkuze & tributaries*MpumalangaNtombe (tributary ofPhongolo)Hlelo*Upper Vaal*Elands*MbyamitiNwanedzi-Sweni*LimpopoMutale-Luvuvhu*MohlapitseNorthern CapeUpper Sak, Klein-Sak &tributaries*NorthWestUpper Groot-MaricoWestern CapeDoring & tributaries*Klaas JaagersRooielsTouwsKaratara-HoekraalHomtiniKnysnaBietou-PalmietGrootBloukransThere are 62 free-flowing rivers in South Africa, of which only 25 are longerthan 100 km (Figure 3.3; Table 3.1). This constitutes only 4% of the length onthe 1:500 000 river network GIS layer. Acknowledging that not all of theseare likely to remain free flowing in the light of development needs andobjectives, 19 of the 62 free-flowing rivers have been identified as flagshipfree-flowing rivers. These flagships were identified based on their representativenessof free-flowing rivers across the country, as well as their importancefor ecosystem processes and biodiversity value. These flagship rivers shouldreceive top priority for retaining their free-flowing character. See pages 37-41for stories of selected flagship free-flowing rivers.The upper Groot Marico River inthe North West province is the onlyfree-flowing river representative ofthe entire north-western region ofthe country. The Eastern Cape andKwaZulu-Natal have the highestnumbers of free-flowing rivers, severalof which are short coastal rivers.River reaches satisfying all of the following requirements were selected as freeflowingrivers:• Permanent or seasonally flowing rivers. Rivers that do not flow every year(ephemeral rivers) were not considered.• Rivers in good condition (A or B ecological category).• No dam in the channel throughout its length. This assessment used 1:50 000farm dams (Department of Land Affairs: Chief Directorate Surveys and Mapping2005-2007). Data constraints prevented consideration of farm dams built after2005, as well as weirs. The Upper Vaal and Upper Marico rivers were specialcases where the long stretch of river flowing freely from source to dam wasconsidered free flowing.• Length ≥ 50 km for inland rivers, with no length threshold for coastal rivers.Ernst SwartzNational map products - 37 -