Impact of Eland on water resources within the Kgalagadi Transfrontier Park
24 October 2012
The last time a similar movement of Eland into the South African side of the Park occurred, was in 2007. According to reports from staff who witnessed the 2007 movement, the animals then were thin and probably looking for better food sources, while this year most animals were in a fair to good condition. It is difficult to say exactly how many Eland moved into the southwest of the Park, but during an aerial census in September 2012, a total of 3 117 Eland were counted in the dunes on the South African side alone. Dr. Mike Knight, who has been flying the plane for many years while aerial counts were conducted, said that during no previous count in the KTFP had so many Eland been observed. It is also not known if some of the Eland came as far as the Central Kalahari Game Reserve, but there is a possibility.
Under normal circumstances, when there are only a small number of Eland on the South African side of the KTP, the solar pumps in the Park are capable of supplying in the demand of the game by filling the reservoirs, tanks and water troughs. The only need for a solar pump to deliver water is sunlight. Since the arrival of the Eland the solar pumps and more specifically the Watermax pumps (which are in the majority) in the Park, could simply not stay ahead. Waterholes equipped with Grundfos pumps and windmills seem to be the only ones capable to cope with the large demand from the animals. Over time many windmills in the Park have been replaced with solar pumps.
Eland behave like cattle in many ways. New problems arose due to the Eland Herds moving into the South African side, which were unexpected. All of a sudden some of the water troughs were found trampled to dust (Eland bulls are much heavier than the normal Gemsbuck and Blue Wildebeest that visit water troughs). Broken troughs caused water to overflow into the sand and reservoirs and tanks ran dry. Some ball valve mechanisms were also damaged due to Eland climbing inside empty water troughs in an effort to get more water. The purpose of the reservoirs and tanks is to have a source of water which keeps feeding the water troughs at night when the solar pumps can no longer supply water. Several water troughs already had to be repaired with cement. In order to do so those water troughs had to be closed for a couple of days to allow the cement to dry before it could be re-opened.
During the day, while tourists are still moving around in the Auob and Nossob rivers, only a few Eland are seen, but after the gates are closed in the evening, the Eland move into the riverbeds where they then empty the water supply in the waterholes, Camera traps that are regularly put out at different waterholes have captured hundreds of photos to prove that. On some photos it is clear that by the end of the day some troughs were full of water - filled by the solar pumps during the day, but later that same evening numbers of Eland were visible drinking and still later the empty water troughs would be clearly visible. The next morning when the tourists reached the water holes, the troughs would be empty, the reason for many questions and complaints. Most solar pumps first pump water into reservoirs and from there the water runs through to the troughs. When the reservoirs still have water inside there is no problem, but with all the pressure coming from Eland as explained above, every morning the solar pumps have to start pumping from scratch. Rangers have witnessed on many occasions that water troughs were full or almost full by the end of a day, only to be empty the next morning.
Nobody knows when the Eland will return to Botswana. Some females are currently calving, which may hold them back longer than expected. It is clear that the water problem will not go away until the big herds move back into Botswana. The problem was not caused by Rangers nor Management not doing their work, nobody knew that such an influx of Eland from Botswana would occur for such a long period (it is currently in its fourth month). The way forward is to prepare to be able to accommodate large number of animals in future, by increasing water storage capacity to ensure sustained water provisioning to animals , whether migrating or resident.
Section Ranger: Twee Rivieren
Kgalagadi Transfrontier Park
Tel: 054 561 2010