Civil Engineering June 2021 | Vol 29 No 5

30 June 2021 Civil Engineering E ncompassing almost 500 000 km 2 , the Karoo stretches across the Western Cape, Northern Cape, Eastern Cape and the southwest of the Free State. The Karoo is bounded in the south by the mountains of the Langeberg, the Outeniqua and the Kougaberge and in the west by the Cederberg and the Bokkeveldberge. In the east and north the boundaries are less defined, merging with the grasslands of the Eastern Cape and bounded by the western Drakensberg Mountains and in the north by the Orange River, merging into the plains of Bushmanland. The Great Karoo com- prises seven distinct regions, of which the Hantam and Roggeveld are one. This article deals with the water supply to three towns in the Hantam Karoo, of which Calvinia is the centre. THE HANTAM KAROO The Hantam Municipality covers 36 128 km² and includes Calvinia, Brandvlei, Loeriesfontein, Middelpos, Nieuwoudtville and Swartkop. Calvinia is ap- proximately 400 km from Cape Town, Springbok, Upington and Beaufort West. 70% of the population of approximately 22 000 people live and work in the towns. Farming is the main economic contributor, with extensive sheep farming, wool and rooibos tea being the primary activities. The Hantam is known for its wide- open spaces, stunning mountain ranges and nature reserves filled with an array of plants and bulbs that cannot be found elsewhere. Since 2013 this area has been in the stranglehold of a severe drought, with the area literally not receiving any rains for seven years. The problem started in Brandvlei in 2009, was followed by Loeriesfontein in 2013 and now Calvinia has started running out of water. Like most other Karoo towns, the Hantam towns are primarily dependent on groundwater sources for their water supply. The only exception being Calvinia, which also has a surface water supply in the form of the Karee Dam. CLIMATE Located in an arid to semi-arid desert climate, the Hantam Karoo is prone to wide variations in temperature from -10°C in winter to 38°C in mid-summer. Rainfall is less than 200 mm per annum, with places such as Brandvlei only averaging 89 mm per annum. The Hantam area is commonly subject to long periods of drought. Rainfall is predominantly in summer and usually in the form of short thunderstorms. Calvinia and Nieuwoudtville are exceptions to this, as they are located on the boundary between the winter and summer rainfall regions. The Karee Dam at Calvinia is highly dependent on good winter rainfalls to impound water. If there is no rain, such as what occurred in 2017 and 2018, the dam does not impound sufficient water, and the town is then totally dependent on its augmenting groundwater sources. THE LOERIESFONTEIN PROJECT Loeriesfontein is located approximately 80 km north of Calvinia and is totally dependent on groundwater sources. The town has a Seven years of drought and the plight of the Hantam Karoo Bulk water supply to three Northern Cape towns Gert Meiring Director BVi Consulting Engineers (Northern Cape) gertm@bvinc.co.za Figure 1 Location map of the Hantam Karoo