Dirt: The Erosion of Civilizations - Kootenay Local Agricultural Society

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Figure 9. Ruins of the first century a.d. Roman city of Timgad, North Africa
(Lowdermilk 1953, 17, fig. 9).
groves, held in place by ancient terraces and banks of earth that guided
runoff from the surrounding slopes to the fields. Hills protected from grazing
retained soil covered by grass and scattered trees. Concluding that elsewhere
the soil had been washed from the slopes, Lowdermilk blamed overgrazing
for unleashing erosion that destroyed the capacity of the land to
support people.
Traveling east, Lowdermilk’s party reached the area where Moses led the
Israelites out of the desert and into the Jordan Valley. Stopping at Jericho,
Lowdermilk found the red soil had been stripped from more than half the
upland area. Deep gullies sliced through valley bottoms, the remnants of
which were still being farmed. More than three-quarters of the ancient villages
on steep slopes had been abandoned, while nine out of ten on the valley
bottom remained inhabited. Abandoned villages stood where the soil
had been stripped away. Thick soil remained on cultivated slopes where
stone terraces were well maintained.
At Petra, the capital of the Nabataean civilization carved from bedrock
graveyard of empires