Ten years after the completion of the much heralded and much maligned Aswan High Dam, Egypt is on the verge of undertaking yet another mammoth, multimillion-dollar hydro-engineering project.
Unlike the High Dam, which was built to harness the flow of the Nile River, the Egyptians now want to tap into the other major body of water available to them, the Mediterranean Sea.
And, again in contrast to the High Dam experience, the politicians this time are listening to the environmentalists before breaking ground.
The current plan is to construct a canal that would run from a point along the country's Mediterranean coast at El Alamein, west of Alexandria, to the Qattara Depression, 56 kilometers away in the desert northwest of Cairo.
The huge, naturally formed depression, with a surface area of about 20,000 square kilometers, lies 134 meters below sea level at its deepest point. The seawater, sluicing down from the coast toward the derpression, will be regulated by water turbines to generate electric power -- enough electricity to save 15 million tons of oil in the first decade of operation alone.
The Qattara Depression will be permitted to fill with seawater until it reaches a level of 60 meters below sea level, which should take between 45 and 55 years. At that point, an equilibrium will be established; the amount of water emptying into the depression will be roughly equal to the amount evaporated from the lake.
Egyptian officials claim that the Qattara project thus will be the first practical combined application anywhere of both solar and hydroelectric principles.
President Anwar Sadat has dubbed the project "the new high dam" and has ordered its immediate implementation, a directive that may be difficult to fulfill as no funding is yet available.
Muhammad Kamel Mahmoud Hamed, an engineer and chairman of the Qattara Project Authority, says construction of the canal and power station could cost anywhere from $1.5 billion to $2.5 billion and that Egypt will seek assistance from international lending agencies, such as the World Bank.
Mr. Sadat's comparison with the High Dam may also have been ill chosen, as that dam, built under President Gamal Abdel Nasser, has been a focal point of political and scientific controversy for several years. Egyptian and foreign scientists alike have blamed it for a range of environmental problems that afflict Egypt, such as soil salinity, erosion of the eastern Mediterranean coastline, and a decline in fertility of the country's precious agricultural land.
Lately, however, the reopening of a joint study by the University of Michigan and the Egyptian Academy of Scientific Research and Technology has begun to challenge the basis of many of the accusations that have been leveled against the dam. Where the ecological effects have proved harmful, according to the study, the fault lies not with the dam but with the failure of politicians and planners to heed the warnings they scientists had given them.
If they had listened, tile drains, for example, would have been installed immediately in farming areas in order to carry off the excess water that the dam made available and that has dangerously increased the salinity of Egyptian soil. Artificial bulwarks could have been constructed to protect the Mediterranean Coast from erosion; before the dam was built, tons of silt carried down the Nile has protected the coast.
But these are the oversights of more than a decade ago. Today, the Egyptian government, although surely excited by the energy-producing potential of the Qattara project, seems determined not to lunge ahead without at least considering the environmental consequences.
"We have established a reasonably effective environmental movement which wasn't there as recently as 10 years ago," says Cairo University botany professor Muhammad El Kassas, Egypt's preeminent ecologist and a widely acclaimed and honored authority on desertification. "The government is listening," he adds.
Dr. Kassas was one of the scientists who went public in the 1960s with his reservations about the High Dam, a stand that nearly got him tossed into prison.
Today, though, he is one of 17 prominent Egyptians on an advisory committee that is trying to look ahead to what the Qattara project may do to the environment. And Mr. Hamed contends that the Qattara Project Authority, the governmental body entrusted with issuing final approval for the beginning of construction, may ultimately veto the whole idea if objections raised by the environmentalists prove compelling.
Already, the authority has ruled out the use of nuclear explosions to dig the canal, a method suggested by a West German engineering firm, and has chosen instead conventional -- and more expensive -- excavation methods.
To date, Dr. Kassas and his colleagues have not committed themselves on the larger question of the long-range environmental impact of the Qattara project. But he has criticized the studies done so far by foreign consultants for their failure to determine what will happen to the water evaporated into the atmosphere from the depression.
One environmental study, cited by Mr. Hamed, found that the amount of water vapor released will be negligible, less than 1 percent of that which moves naturally across northern Egypt. The climatological effects of the evaporation, according to this theory, will be local only.
"As far as the engineers are concerned," says Dr. Kassas, "the water vapor goes up into the sky and that's the end of it."
What now must be examined, he says, is the extent to which the increased humidity will be transported by the prevailing winds. If humid air were carried east into the Nile delta, Egypt's most bountiful agricultural area, the relative humidity of the region could increase. Even a rise of only 10 percent, Dr. Kassas believes, would sharply increase the incidence of fungal plant diseases that thrive in a humid environment.
Environmentalists likewise are saying that even though the salty water in the vast depression will be below sea level, there is the danger that it may move, through osmosis, out of the depression and toward to soil in the delta, where it would threaten to increase the salinity of the farmland.
The seismic stability of the area also has been questioned by some scientists who fear that the land around the depression is more fractured and prone to tremors than is the land surrounding the High Dam.
Though not unmoved by these concerns, the country's engineers and social planners anxiously point to Egypt's alarming population growth. By the year 2000, they say, the number of Egypt's inhabitants will have risen from 40 million to 66 million and per capita demand for electricity will have risen fivefold, a demand that cannot possibly be met by the country's known oil reserves.
Egypt has no choice, they argue, but to exploit seawater, its last regenerative resource of constant energy.