BackgroundSouth Africa is mostly a semi-arid, water-stressed country, with an average precipitation of about 450 mm/yr, well below the world average of about 860 mm/yr. Traditionally river water and surface water run-off has been stored in strategically placed large storage dams built in catchment areas. The supply of surface water either from rivers or runoff has been vulnerable to short and long term climate fluctuations with reduced water supplies being affected by drought (Hartnady et al., 2014). The desalination of sea water could be seen as an alternative source of water to supplement Municipal water supply but the process is expensive primarily because of the high cost of energy required to pump sea water or other saline water through membranes in a process known as reverse osmosis. Desalination plants using reverse osmosis have been installed in coastal towns such as Mossel Bay, Knysna and Plettenberg Bay (Mallory et al., 2012) A high percentage of the Earth's fresh water is stored underground which can be extracted either through pumping or using artesian pressure through wells. In semi-arid areas such as the Klein Karoo in the Western Cape, aquifers may not recharge at a sufficiently sustainable rate relative to the rate of withdrawal, especially during periods of drought. In situations such as these, the extraction of water is therefore considered as "mining" of a non-renewable resource which has to be carefully managed (Hartnady et al., 2014).
The Blossoms Well FieldConsidering the above and contemporary concern about global warming and its effects on water and food security, the Oudtshoorn Municipality in the Klein Karoo has embarked upon the exploration of a deep artesian aquifer situated approximately 30 km south of the town in the Northern foothills of the Outeniqua mountain range. In addition, the Municipality is developing what is known as the Blossoms Well Field of boreholes of between 500 m and 600 m deep within the area of the aquifer to supplement the current water supply for both the town and the surrounding rural areas. The aquifer is fed by water infiltrating primarily from the southern slopes of the Outeniqua range (see Figure 2). The area of the well field is shown in Figure 1 together with boreholes used in this project. A simplified profile AB of the geology extending from the Outeniqua range to the Blossoms wellfield in the vicinity of C1B3 and C1G1 is shown in Figure 2.