12-Aug-2007 -- This Confluence lies near the centre of Sua pan, one of the salt lakes that comprise the Makgadikgadi Pan. The size of Sua pan has to be experienced to be comprehended. It is approximately 100 km long and 40 km wide, a vast area of nothing. The horizon is endless and in some areas, one can view the flat pan surface for 360 degrees.
The geology of Sua Pan is unique, comprising two layers of sediments. The upper layer is a semi-confined aquifer of alkaline brine and consists of variable clays, silts, and sands to an average depth of approximately 38 m. The lower layer consists of sands, cemented with calcium carbonate which extends down to the Kalahari bedrock. Under normal dry pan conditions, the brine surface can be found approximately 1 m below the surface of the pan, the area above this being kept moist by a process known as evapo-transpiration. Below this level all the voids in the clays and sands are filled with brine. No matter what the season, the centre of the pan varies between moist, muddy, and water-logged. The brine surface actually varies in harmony with the moon phase not unlike the tides of the oceans.
The clay sediments and brine are thought to have originated from the drying up of what once was the largest lake in Africa, stretching from the Zambezi in the North, through Hwange National Park in western Zimbabwe to the Central Kalahari Game Reserve in the West. What remains is one of Africa's natural wonders – the Makgadikgadi Pans.
Traversing the pans is a major challenge as the grease-like clay quickly fills the gaps in even the most aggressive of tyre treads, effectively smoothing the tyre and reducing traction to zero. Even walking on the mud is testing; at some areas it is as slippery as walking on ice while in other areas one sinks into the clay like quicksand. The only vehicle that will reach most areas of the pan is one with a very low weight to tyre area ratio such as a light quad bike.
The trip was planned as a day outing from our home nearby by trailering two motor cycles and two quad bikes to a small village named Mosu. From there, it was 18 km directly across the pan to the Confluence. We set up a gazebo at the edge of the pan near Mosu to protect our wives and children from the heat while we rode to the site. Despite being winter, the temperature was still well above 30 degrees C.
In retrospect, it was prudent to set off before lunch despite the feeling of the group that the 18 km would not take more than 20 minutes. Thankfully however, we did leave before lunch as the trip took two and a half hours.
The first few kilometres went very well across a relatively dry pan, but all too soon the mud started to spray up from our rear tyres, an indication of a very wet pan despite no rainfall in the area since February. At about this time, one of the quad bikes overheated due to the increased resistance of the mud and suffered a suspected engine seizure. We left it for later collection on the return trip.
About two kilometres from the Confluence, the pan surface became so wet that the motor bikes ran out of momentum and mine, being the larger and heavier of the two, got stuck. With the Confluence so close, there was no way that we were going to give up there and the party proceeded on foot while the remaining quad bike shuttled us one by one to the Confluence. I had a great sense of elation and achievement when reaching this Confluence as the area is very special to me.
After the obligatory photos and a cold beer we began the journey back to extract and recover the stricken vehicles that littered our route there. Getting the motor bike out and moving again was perhaps more suited to rugby scrum training! I ended up pushing the bike for about two kilometres idling in first gear before I could ride it as the surface of the pan was as slippery as ice. Any slight bit of weight or power would dig the rear wheel into the surface and the bike would be stuck again. More than once the rear wheel slipped out of control and I found myself facing where I had just come from. How I didn't fall off remains a mystery!
We returned on our own tracks, not wanting to impact too much on the pristine beauty of the pan by leaving meandering tracks in an area where nobody had ever been before. Although this is a spectacular Confluence to visit for its beauty, equal views are within easier reach without having to cross untouched pan surface. The ecosystem of the pan is so delectate that it is prudent and environmentally responsible not to drive randomly across the pan but rather to follow in other people's tracks as far as possible.