National Geographic : 1990 Feb
FEBRUARY 1990 GEOGRAPHIC Mono Lake to Get __ Some Water Back Since 1941 Los Angeles has been obtaining about 15 percent of its water supply by diverting streams that feed California's Mono Lake. Now the city has been told to stop taking so much water. The lake-just east of Yosemite National Park -is an important habitat for millions of migratory birds and the brine shrimp on which they feed. Since the diversion began, the level of the lake has dropped more than 40 feet, creating land bridges that make birds on island nesting sites vulnerable to predators, notably the coyote (NA TIONAL GEOGRAPHIC, October 1981). An El Dorado County judge has ordered Los Angeles to limit diversion of Mono basin water until the lake can rise to an acceptable level. Meanwhile the state has authorized as much as 60 million dollars to help Los Angeles pay for new water sources. To get it, the city and environmentalists must agree on ways to preserve the lake. "We're laying the groundwork for solving the problem," said Martha Da vis of the Mono Lake Committee, an environmental group. But city officials contend that the funds will pay only a fraction of the costs of alternate water supplies-most likely purchased from farmers in the San Joaquin Valley. A state agency has begun hearings on what changes to make in how Los Angeles gets its water. It will rule on Mono basin water rights by 1993. Good News Hatching for Whooping Cranes Wildlife officials are not yet whooping for joy. But they are smiling with relief at a steady growth in the number of whooping cranes, a bird that had teetered on the edge of extinction (GEOGRAPHIC, May 1979, April 1984). The crane popula tion, which dipped as low as 21 in the mid-1940s, has topped 200, including more than 150 in the wild, and is climb ing. By the mid-1990s officials hope to release 15 to 20 captive birds annually into the wild. A flock of cranes at the U. S . Fish and Wildlife Service's Patuxent Wildlife Research Center at Laurel, Maryland, increased enough for 22 of its 54 birds to be transferred to the International Crane Foundation facility in Baraboo, Wisconsin, last fall. Splitting the flock will protect it from catastrophe if disease strikes, according to Scott Hereford, crane flock manager at Patuxent. "You don't want to put all your eggs in one bas ket," he says. The last remnant wild flock-which breeds in Canada and winters at the Aransas National Wildlife Refuge in Texas-now numbers about 140 and ANNIEGRIFFITHSBELT produces 10 to 15 chicks a year. But a flock that summers in the Rocky Mountains, introduced under a U. S. Canada agreement, dropped last year to 13, mostly male. A female born at Patuxent was shipped out last spring in hopes that she would become half of a breeding pair. She "took up" with a male, Hereford says, "but when the flock flew south, she remained." DAVID CARRIERE,AFTERIMAGE INC. 1990 Census to Take a TIGER by the Tail « ATIONAL GEOGRAPHIC has to pro duce 11 million copies of one map," says Robert W. Marx. "We have to produce one or two copies of a million maps." That is how Marx, chief of the Geog raphy Division of the Census Bureau, explains why 325 million dollars-and more than a decade-are being spent to compile a gigantic data base file called TIGER for this year's decennial census. TIGER stands for topological ly integrated geographic encoding and referencing, and never mind what that means. The system is designed to make sure that every census taker knows the area he or she is responsible for, that every census supervisor can be certain that an area has been covered, that cen sus information can be disseminated accurately about areas as large as any of the nation's nearly 3,300 counties or as small as a city block. Working in cooperation with the U. S. Geological Survey, Marx and his Census Bureau colleagues are assem bling a computer file that contains-by name and in digitized map form-the range of address numbers for every street and road in the nation's 345 larg est urban areas, every creek, lake, riv er, and railroad. They have devised a way to produce the individualized maps that enumerators will use when they collect census data beginning April 1 and that analysts will use when they study the results.