By Kenyi A. Spencer, PhD
March 17, 2014 (SSNA) — Juba is really in the wrong place, geologically and geomorphologically speaking. The person who planted Juba here never looked into what the plate tectonics below us are doing. He never looked closely at the geological maps of the African continent. In the first place, Juba is perched right at the knife-edge of the western part of the East African Great Rift. Talk of the St. Andrean Fault of Africa! The dangers of our African plates are that the Ethiopian Plate is moving southwards, pushing against the heavier African Plate. To the East, the smaller Somalian Plate is moving away from it all. Good enough, the movement of these plates are so slow worrying over them is not a serious matter now, but they are moving. If the move is a smooth slide, worry is not necessary but if the movement turns jerky, then cracks happen and that’s when tumbling of the overburden happens and when this does, the Earth’s Crust begins to fall apart.
Juba is definitely in the wrong place. But before we ponder over the next worry let me ask this nasty question: which of the two came first, the Nile or Jebel Kujur (the Mountain West of Juba)?
If Jebel Kujur, then we have a big problem; the Nile has been constrained between the Jebel and the Gumbo Escarpment to the east. The Nile has been wandering in this narrow enclave in great abandon, depositing and re-depositing silt, sand and flotsam in this area for millions of years, sometimes wending east and then swinging back west again. In the past fifty to one hundred years the Nile had come to the end of its eastward move and is now on the return journey westwards. This is evidenced by the 90˚ crook at Cassafa, near Kator, where the river north of Lologo bends sharply eastwards. The river has been busy around here for so long. This means that most of Juba is built on alluvial deposits of sand, silt and mud. And, we know from the Bible what happens when we build on sand. Buildings as tall as or taller than the UAP Plaza are courting disaster. But this is not our paramount worry now over Juba.
The main worry is this 90˚ angle. This is where the river water is digging and scouring land away at such an alarming rate it may not take long before water is lapping at the steps of the Cathedral at Kator. The scouring is due to the fact that water at the Lologo end is increasing in speed. When last measured in 2006 it was moving at the moderate rate of 1.2 cubic-metres per second. In 2013 it had increased to 2.3 mᵌ/sec. This is in comparison with the speeds of 0.7mᵌ/sec. (2006) and 0.9mᵌ/sec. (2013) on the Gumbo end. The large difference of speeds between the west and the east is a matter for concern. It disturbs the gentle laminar flow of water, causing whirlpools and severe eddy currents on the riverbed and a build-up of a backward hydraulic pressure. As the pressure recedes backwards, it comes against the rapids at Lologo, south of Juba, throwing the water into a U-turn back-lash, thus its impact, and, thus the further scouring at the angled crook. The frequency of whirlpools and rapid eddy currents causes the river to deepen at the Lologo end and on the river floor. The crumbling of the banks at Cassafa and Lologo was made worse by people excavating soil at the spot for bricklaying. This encouraged the river to dig deeper into Lologo and Cassafa. No wonder that end is now devoid of trees while the east end still holds firm its trees. Soon Cassafa, Lologo and Kator will have to be relocated to someplace else. But, what do we have to do to solve the problem once and for all? Halt the Nile’s westward march by constructing a straight channel connecting Lologo to the Gondokoro Island to take the water in a direct path southwards so as to relieve the speed effect at the Cassafa end. But this will need another bridge some metres east of the current one. This is expensive but what a small price to pay as compared to the damage that is looming.
Juba is in the wrong location. If you measure the angle of inclination to the horizontal between the Raids at Lologo and Juba Town, the Nile is elevated 2˚ above the Town. This is equally as hazardous as the effect of the 90˚ angle. And, it gets worse…
Last week, scientists reported that a second ElNino Effect is building up in the tropical belt of the Pacific Ocean, and that the icebergs of the North Pole are thinning. This spells severe warm currents and high cloud content. The last ElNino 15 years ago may look like breakfast if this is to happen. Flooding will be more than everywhere; and, I hope this does not touch our Lake Victoria in the centre of Africa.
Juba is currently at the mercy of a concrete dam at Jinja in Uganda. It is this wall that is holding Lake Victoria back. This wall was built 60 years ago this year. The problem is that at sixty, concrete and man are the same. They become cranky and temperamental; they crack and bend over easily. If this happens Juba will be washed away in the resultant deluge. A new dam may be slated to replace the old one but time is of the essence. All this looming danger is if Jebel Kujur was here first in the history of this continent.
However, if the Nile was here first, then we have a chance. We can quickly begin to shift Juba west of Jebel Kujur. The area between Jebel Kujur and Jebel Bungu might be the only one with firmer ground. Although that is still too close to the Albertine Faultline. One cannot tell when the next heave will happen. It could be in the next a thousand years, or perhaps 500 years, or perhaps tomorrow.
Another problem is that Juba is too close to the volcanic Rejaf Mountain. No one knows exactly what rumbling noises are generating in the bosom of this volcanic heap. Any slight rupture may set the faultline cracking. These are the woes of our small (but growing) city. We need to do something drastic to avoid being caught a sitting duck. I know our major pre-occupation now is insecurity. This is also insecurity at its worst. The disaster it spells is total. This is the third time I am sounding this bell in the past 6 years. I hope someone out there is listening. Otherwise we are waiting for a disaster bigger than any seen on the African continent. I hope this is not a voice of a doomsayer but the factual reality of Juba.
Kenyi A. Spencer is an environmental economist, international trade specialist, and private sector development consultant based in Juba, South Sudan. He can be reached at [email protected].