ROME (Jul. 22)
Ancient irrigation systems in Israel can be copied with good results today and, in some cases, can even be put back into use after cleaning and repair, experts of the U.N. Food and Agriculture Organization reported here.
Dr. W.C. Lowdermilk, a soil scientist from Berkeley, California, and Wayne Miles of Dallas, Texas, have told how modern bulldozers are being used in restoration of 2,000-year-old cisterns in a project conducted under the expanded program of technical assistance of the United Nations and the specialized agencies.
Reporting on an exploration of the Southern Negev, beyond Beersheba, Dr. Lowdermilk said that the Nabataeans, whose golden age was from 200 B. C. E. to 200 C. E. and whose capital was Petra, were able to conserve flash flood waters in these regions of low annual rainfall. Their methods were continued under Byzantine rule up to the time of the Islamic invasions in the 7th century.
“Thousands of cisterns for storing rainwater had been dug in the chalky limestone of the lower slopes of the hills,” Dr. Lowdermilk stated. “Small open ditches were dug to lead storm run-off of these slopes into the small cistern mouth that opened into a jug-like receptacle underground. These cisterns may be located from considerable distances by the whitish pile of spoil from excavations.
“Much larger cisterns were dug into the chalky cliffs along the larger wadies. The cistern was dug to depths well below the floor of the Wadi channel but the opening was cut about one to one and a half meters above so that the cistern would not be filled with gravel and silt. Such cisterns may have capacities of 25,000 to 70,000 cubic feet. Where needed, columns of chalk were left to support roofs of the excavations.”
PLAN FOR UTILIZING ANCIENT SYSTEM STARTED BY EXPERT
Water is desperately needed in this desert area now, Dr. Lowdermilk pointed out. Wells are out of the question either because the ground water is saline or because its level is too far down. In an effort to utilize the ancient system Mr. Miles, of the F. A. O. soil conservation team, hit upon a plan for filling the cisterns after they had been cleaned out.
With a bulldozer, he built an earth embankment across the wadi channel just downstream from the cliff-openings into two cisterns. The crude earth dam had no spillway, for it was expected to break when overtopped. The plan worked. The two cisterns were filled with storm waters; the earth-filled dam broke; and the rush of impounded waters swept it away, keeping the bottom of the Wadi channel at its former level.
Dr. Lowdermilk wrote F. A. O. that the filling of the cisterns by the use of a bulldozer for five hours save water haulage by truck over a distance of 200 kilometers. He reported that the Nabataeans had also learned to store rainwater in soil. “These ancient experts in desert water supplies had learned some basic facts about soil moisture relations,” he wrote. These relations involve complicated calculations of capacity of soil to absorb water, evaporation loss, amount of water necessary to grow crops, depth of soil needed to store necessary water, and soil embankment heights necessary for each basin into which water is diverted.”