Water Shortage Pits Man Against Nature

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NEWS CALIFORNIAN DROUGHT------Water shortage pits man against nature San Francisco trict meteorologistJohn Stremel finds the in release liquid propane into the atmosphere HEAvY rains and snows fell in California last itial results of the cloud-seeding programme at cloud level in the hope of generating addi week, bringing a welcome respite to this state "very encouraging", although actual in tional runoff into reservoirs of the State that has now suffered five years of drought. creases will not be calculated until the end of Water Project. As welcome as it was, however, the precipi the season. Some California cities have begun to look tation will not go very far to restore the with Over the high hills of Santa Barbara, cloud toward a source of almost unlimited water: ered landscapes, dry reservoirs and fallow seeding has led to a 25 per cent increase in the sea. Although desalination plants have farmland that have become all too common rainfall, with rain falling earlier during operated for years in Middle Eastern coun in California. storms and more intensely. Most efforts do tries, and even in Florida in the United In the face of nature's adversity, engineers less well, Henderson says- the process typi States, they have traditionally been con and planners are now turning to scientific cally yields a 5-15 per cent increase in an sidered too expensive for use in California and technological solutions to the water nual precipitation. because they require huge amounts of en- shortage. Instead of praying for rain, they are Silver iodide, used in 95 per cent of all considering such options as seeding clouds cloud-seeding efforts worldwide, is the ma over the Sierra Nevada mountains, desalting terial of choice for rain-making, but resear Pacific Ocean seawater and piping fresh chers are testing a variety of other materials. water thousands of miles from Alaska. Dry ice, for example, can be used when Although it has rained little in California cloud-top temperatures are between -4 oC in recent years, the drought is not due to a and -5 °C, warmer than the conditions for lack of storms, says Tom Henderson, presi silver iodide. And Atmospherics is experi dent of Atmospherics, Inc., a cloud-seeding menting with different organic compounds company in Fresno. that modify the seeding agents for use in dif The drought years have actually produced ferent cloud conditions. 80 per cent of the number of storms of nor Henderson has also seeded a few clouds mal years, he says. Instead, the problem is with the bacterium Pseudomonas syringae, that the storms in wet years were generally which is usually found on plant leaves, where taller, thicker, longer-lasting and much it nucleates ice crystals. Atmospherics scien ergy. higher in liquid water content than those in tists are still optimizing its use in laboratory But the city of Santa Barbara has decided the drought years. So, while some regions tests, but they have found it can form crystals to tolerate the high cost in return for a guar have seeded clouds for years to increase rain at the relatively high temperature of -0.5 OC. anteed water supply. In that central coast fall, this winter several more communities In the Plumas National Forest, the state city, where the two main water reservoirs are have turned to various cloud-seeding tech Department of Water Resources and the US just 12 and 14 per cent full, officials say con niques to enhance the weaker storm systems. Forest Service are developing an experimen struction of a desalination plant will begin by Monterey County is paying about tal ground-based cloud-seeding programme midsummer. The city currently delivers $130,000 to send airplanes into every cloud that uses propane to trigger precipitation. water to its customers for $200 per acre-foot, that has the potential to produce rain for the Propane has been used by the US Air Force but it will pay contractors $1,900 per acre area this season. The planes release tiny crys to clear fog at airports, but this project is ex foot for the desalted water when it becomes tals of silver iodide which, at appropriate pected to mark its first use in cloud-seeding. available in a year. (An acre-foot of water is temperatures and sites within the cloud, act Courtland Bennett of the US Forest Service 326,000 gallons, or enough to supply a sub as nuclei for ice crystals, which later become says the plan calls for ten seeding stations on urban family of five for a year.) rain or sleet or snow. Monterey County dis- mountain ridges over Feather River to Desalination plans are also under scrutiny Drought threatens Californian bird populations CALIFORNIA'S drought is putting at risk sev• colonize many areas so that a local disas• water temperature to spare the winter• eral populations of the state's endan• ter does not destroy the species, says run salmon. The species is protected gered and threatened species, including Robert Mesta of the Fish and Wildlife Ser• under the Endangered Species Act. a pioneering pair of bald eagles and sev• vice. The Lake Cachuma pair "represent But many other species of fish are also eral types of fish. the seed of a Southern California popula• in danger, and are not yet covered by the At Lake Cachuma in central California, tion", he says, and their progeny will prob• Endangered Species Act, says Peter US Fish and Wildlife Service biologists are ably return to the lake. Mayle, professor of wildlife and fisheries worried about a breeding pair of endan• Further north, in the Sacramento River biology at the University of California at gered bald eagles. Although this part of delta, winter-run chinook salmon are in Davis. Mayle recently completed a survey the state was once a common breeding danger. For a number of reasons, the of all the native fishes in the state and ground for the eagles, the birds retreated salmon population, which runs up the Sa• found that of the 113 species, 7 4 were in north in the 1950s, and it was only two cramento River to spawn, has been dim• need of special protection. Six of those years ago that this pair became the first inishing for several years and last year species had become extinct since 1957, to recolonize the Lake Cachuma territory. reached a record low of 441. Now biolo• and 16 were formally listed as endan• But the· lake, which supplies water to gists are worried that after upstream gered. Most of the damage had been Santa Barbara, is just 14 per cent full, water is diverted by federal water pro• done by water dive~sions and the intro• and biologists fear that if it loses its fish jects to farms and cities, the river will be duction of predatory game fish, but for populations, it will also lose the pair of too warm for the fish. Water tempera• some species the drought could be the resident eagles as well as 15 other tures over 56 "F ( 13.3 oc) are deleterious final straw. Mayle predicts that with an• eagles that winter there before returning to the salmon, and temperatures over 60 other year of drought the state could add to their northern nesting grounds. OF (15.5 oc) are lethal. delta smelt, coho salmon and spring-run With only 2,000 breeding pairs of Officials with the federal Central Valley chinook salmon to the list of species that eagles in the continental United States, it Project are now studying ways to change have disappeared from California is important to encourage the raptors to water delivery plans or lower the river- ~~ffi ~&