Aerial photographs show many strand lines, representing previous temporary high lake levels, on Shala's southern shore. Between about 10,000 and 5,000 years ago a large part of the rift valley was covered by a large lake, now called the Galla Lake, which was about 110m above the present level of Lake Shala. Shala was then marked only by circular string of disconnected islands, the tops of the highest peaks of the rim.
Probably sometime during this high lake period - or a previous one - eruptions of basaltic lava through the lake produced the tuff ring now occupied by Lake Chitu, about 1.5 km south of Shala. In Gallinya, 'Chita' means 'that which is broken or separated' refering to a local tradition that Chitu was once connected with Shala, but the tow lakes separated long ago as the level of Shala declined. Strand lines within Chitu prove that its water level was once higher, but it seems improbable that the Galla, who only entered this part of Ethiopia within 400-500 years, could have ethnic memories of the high lake levels from 5,000 years ago. Were there more recent high lake levels in Chitu, or connecting Chitu with Shala?
Chitu is a beautiful crater lake (crater diameter of 1.6 x 1.2 km) with a population of 5,000-10,000 flamingos. The crater's rim (about 80 m above lake level) is composed of gray tuff containing bomb sags, cross-bedding and dune/antidune structures, comfirming that it erupted through a shallow lake. Whitish, inward dipping sediments occur up to 30 m above the lake. About 2 km south of Chitu an arcuate ridge is all that remains of two other tuff rings (one about 1.4 km and the other about 0.8km in diameter), somewhat older than Chitu. This ridge is called Maja Faro, meaning "Water was once there"; and the local Galla people say that Lake Shala extended into this eroded ring-pair only three generations earlier. It is impossible for Shala to have been that high so recently; but perhaps if the rainfall were only slighly higher then, a shallow swampy lake could have existed during rainy seasons.
Small collapses a few meters across occur along approximate North-South lines between Shala and Chitu. One imprssive, vertical walled hole is about 10 m deep and seems to have a horizontal opening at the bottom. These collapses have probably formed within sediments filling a tentional fissure - a gya - such as occur near Negheli and Fantale.
This interesting, beautiful and largely unexplored southern shore of Shala can be reached by driving 23 km along the Shashamane-Soddu road and then following a four wheel drive track a futher 25km north to the lake.
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