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NATIONAL WATER RESOURCE STRATEGY SOUTH AFRICA’S WATER SITUATION AND STRATEGIES TO BALANCE SUPPLY AND DEMAND UPPER ORANGE WMA. WMA 13: Upper Orange - Rainfall and Evaporation. WMA 13: Upper Orange - Base Map. WMA 13: Upper Orange - Land Use.
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NATIONAL WATER RESOURCE STRATEGY SOUTH AFRICA’S WATER SITUATION AND STRATEGIES TO BALANCE SUPPLY AND DEMAND UPPER ORANGE WMA
30 % National Upper Orange WMA 20 % Contribution 10 % 0 % Other Trade Mining Finance Transport Electricity Agriculture Community Government Construction Manufacturing Sectoral contributions to the economy (1997)
WMA 13: Upper OrangeGroundwater • No large porous aquifers found in WMA • Relatively large quantities of groundwater abstractable from fracture zones at dolorite intrusions - recharge rates lowover most of WMA • In drier parts of WMA groundwater constitutes main (and in many cases only) source of water for rural domestic supplies and stock watering • Severe over-exploitation of groundwater in some peri-urban areas (also at Petrusburg in Riet/Modder sub-area) due to increasing irrigation from groundwater • Although proportionately small component of water available in WMA, it constitutes the main source of water in much of the rural areas.
WMA 13: Upper Orange Water quality • In natural state quality of surface water in WMA is good, particularly water from Lesotho Highlands • Irrigation return flows has major impact on salinity in lower Riet River - water transferred to Riet River from Vanderkloof Dam for blending and water quality management purposes • Natural pan below Krugersdrift Dam adds salinity to Modder River • Water quality in Lower Riet River is of concern - also impacts on water quality in Lower Vaal River and at Douglas Weir • Quality of groundwater is good in eastern high rainfall parts
WMA 13: Upper Orange Key issues • Yield from Upper Orange WMA by far largest of all WMAs in the country • Significant potential for further water resource development • Main source of water for Lower Orange WMA (including Namibia)and for Fish to Tsitsikamma WMA • LHWP has major impact on water availability in Upper Orange WMA • Fluctuating releases from hydropower turbines impact negatively on some users. • Upstream water transfers negatively impact water availability for power generation
WMA 13: Upper Orange Key issues (2) • Hydropower generation at Gariep and Vanderkloof Dams forms important component of Eskom’s peak generation capability • Surplus water available in WMA and will in future be after completion of Mohale Dam • Over-exploitation of groundwater experienced in localised areas • Needs for increased future water transfers to Upper Vaal and Fish to Tsitsikamma WMAs • Flood management of major importance for protection of developments along Lower Orange River
WMA 13: Upper Orange Water resources under control of the Minister • Transfer out of water from Senqu River in Lesotho to Upper Vaal WMA • Transfer out of water from Marksdrift to Douglas Weir (Lower Vaal WMA) for water quality purposes • Transfer out of water to Fish to Tsitsikamma WMA (Orange-Fish transfer) • Release of water to meet needs in Lower Orange WMA and for Namibia • Current reservation of water for hydropower generation by Eskom for peak clipping purposes • Large scale water resource developments on Orange, Caledon and Kraai Rivers subject to authorisation at national level