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The Lost River

DESERTIFICATION HAS A FIRM foothold in China, where land degradation costs $6.7 billion in economic damage annually and affects the lives of 400 million people. Since the 1950s, the annual rate of land on the brink of desertification has increased by about 40 percent, with the estimated current rate being 2,460 square kilometers per year. The cause of these modern losses is no mystery: In China, as in every other country where desertification is a problem, it is most often caused by the environmental pressures of an increasing population, now at 1.2 billion, compounded by economic pressures that lead to inadequate water- and land-management practices. But the lower reaches of the Black River in Inner Mongolia, near Black City, stand as a testament to unknown forces in the past, an ominous warning. This stretch of the Black River has disappeared.
One of the largest geological features visible from space, the dry Black River Delta fans out into the Gobi Desert like a forgotten promise. The lost river took with it many lakes and resulted in the abandonment of 10 ancient cities. This region once supported prospering dynasties. For the past 500 years a land of dwindling grasslands and sparsely scattered herdsmen, the Gobi may hold secrets about the process of desertification. Dr. Gu Wei-zu has worked here for 10 years to discover where the Gobi's water comes from today and what happened to it in the past, using hydrological experiments, satellite imagery, and chemical analysis of groundwater.
The encroaching, mobile desert that the term "desertification" conjures was evident in some areas of the Gobi that we visited, near the lost and ruined cities and especially in the dying forests. We walked among these forests with a deep sense of desolation. The largest and most dramatic is the forest of poplars, (Populus euphratica) found near the Oasis of Ejin. Hundreds of dead trees seem to writhe in agony, twisting their branches toward the sky or bending them back toward the parched earth. Some defy death with a single living branch, a few green leaves, a tiny sapling growing from black, twisted roots; others stand sere and stark against the striated clouds. The underlying cause of their deaths remains unknown, a murder mystery of monstrous proportions. The arm of the Black River that once reached toward the oasis has disappeared and the groundwater table has dropped, but the reasons for this change remain unexplained. It appears to be natural rather than human-made, but that could change. The Chinese government's plan to construct a concrete-lined channel for the lower portion of the Black River may further cut off the water that per colates to this dying oasis, intensifying the ongoing desertification.
-Suzanne Powell
From "When the Sand Comes" EarthWatch Journal, May/June, 1999