When the Kruger National Park (KNP) was first established, five major rivers ran through the park all year round, but other than that permanent sources of water were few and far between. In the winter months animals got water from depressions in the earth that filled during unseasonable rains or moved into areas closer to permanent water.|
As early as the 1930s artificial water points were provided for the game, but in the 1960s and 1970s the number of boreholes and dams in the park increased dramatically. This was in part driven by the fact that the park was completely fenced on its western boundary by 1961, stopping animals like zebra and wildebeest from migrating westwards to find water.
The boreholes were intended to allow animals to survive drought years by helping them gain access to water, and to help smooth out big surges and dips in animal numbers caused by droughts, in keeping with ecological thinking at the time. At the time it was anticipated that it would be of especial help to the rarer antelope like tsessebe, roan and sable.
More than 300 boreholes were drilled and about 50 dams were placed on both annual and seasonal rivers prior to the 1980s. With time it appears that the provision of artificial water seemed to favour some species over others, especially bulk grazers like buffalo and zebra, as well as possibly wildebeest, white rhino and elephants.
With the lions spreading out through the landscape to follow the more common antelope, it also adversely affected brown hyenas, and contributed to the decline of tsessebe, roan and sable. However, it never entirely stabilised the fluctuations in animal numbers, which continued to follow the rainfall patterns.
With hardly any part of the park more than five kilometres from permanent water, the effects of the herbivores on the grasses and trees was spread evenly across the park, which can have negative effects on biodiversity. In the late 1990s, as ecology grew as a science and the park altered its management strategies, the importance of fluctuations in natural populations was recognised.
This led to a re-assessment of the water policy, leading to a revised water distribution policy that was intended to maintain biodiversity. This resulted in the closure of over 150 boreholes in the park, many of which were away from the main tourist roads, and many of the earthwalled dams in the park have been broken down or fallen into disrepair.