气候变化给供水和生态系统带来压力

Peter Moyle has had his ups and downs during fishing trips on the Sacramento-San Joaquin Delta.

这位正规欧洲杯买球网站戴维斯分校的生物学教授一直在追赶, 在三角洲数鱼放生已经超过35年了. 他目睹了种群数量的上升和下降, 但主要是下降趋势, 特别是对本地物种.

“δ itself is not a good place to be a fish these days,” Moyle said.

Global warming and an insatiable thirst driven by population growth are conspiring to put California’s water sources and the ecosystems that depend on them at risk.

δ, which supplies water for two-thirds of Californians — nearly 25 million people — has experienced a collapse in native fish species that scientists blame partially on diversions for agricultural and urban use. 在内华达山脉, 全球变暖正在改变积雪和径流模式, 威胁到该州的另一大水源.

有这么多的利害关系, the 正规欧洲杯买球网站 has made water one of its top research priorities. As UC scientists study the effects of temperature change and human activity on the state’s key water supplies, they are exploring solutions for balancing population needs with the long-term health of California's unique ecosystems.

In the Delta, native fish species are declining; six are listed as endangered or threatened. 50年来, water at the southern part of the Delta has been exported for agriculture in the Central Valley and for millions of users in Southern California and San Francisco Bay Area cities. Fish can be sucked into the gigantic pumps used to divert water, 但科学家推测，这改变了河流的流量, 再加上污染和入侵物种, 也破坏了三角洲的生态, 导致鱼类数量锐减.

除了, many of the levees that protect islands in the south and central Delta are in danger of failing due to age, 糟糕的建筑和海平面上升. Maintaining most of these levees is not cost-effective and is a poor way of managing land and water, 根据最近的研究.

重新检查外周管

所有这些因素导致一些科学家, 包括正规欧洲杯买球网站戴维斯分校的一组研究人员, to support building a peripheral canal that would take water from the Sacramento River and bypass the Delta on its way to end users. 1982年，修建外围运河的计划被否决, largely by Northern California residents concerned about a Southern California water grab.

奥巴马政府召集了一个三角洲问题咨询小组. 阿诺德•施瓦辛格, 呼吁恢复生态系统, 创造更可靠的供水系统, promoting conservation and establishing an oversight commission to manage the vast waterway.

Five bills with goals similar to those of the governor’s Delta Vision panel are making their way through the state Legislature. The legislation includes a proposal to create a Delta Stewardship Council, 谁有权进行修复工程, 包括外周管.

The best thing for fish and the environment would be to stop pumping and water diversions, 根据2008年的一份研究报告. “我们认为这不会发生,莫伊尔说。, co-author of the Public Policy Institute of California Public Policy Institute of California report that calls for the construction of a peripheral canal and for allowing some Delta islands to flood permanently.

修建运河的支持者得到了州长的支持. But opponents say a canal could lead to salt water incursions that would hurt the environment, farmers fear their irrigation allotments will be cut and many landowners of islands that would be flooded aren’t keen on the idea.

“If you have to export water, you can’t do what you’re doing today,” Moyle said. “The peripheral canal is one of few options that seem to make some sense.”

A canal would remove the effect of the pumps and restore a more natural water flow. It is also the most cost-effective way to manage water in a way that provides for human needs and the environment, 完成2008年报告, 是莫伊尔和杰伊·隆德写的吗, 威廉Fleenor, 威廉·班尼特, Richard Howitt and Jeffrey Mount from UC Davis and Ellen Hanak from the Public Policy Institute.

“这是细节决定成败的事情之一. 你必须用一种聪明的方式来做,莫伊尔说。, who's also associate director for the Center for Watershed Sciences at UC Davis, which conducts problem-solving research in restoration and water resource management, 主要在中央谷地内, 内华达山脉, 海岸山脉和圣华金三角洲.

调查积雪

气候变化正使另一个州的水源处于危险之中. 在内华达山脉, 全球变暖导致积雪融化的时间提前, which leads to less water for reservoirs during the dry summer months, 罗杰·贝尔斯说, 正规欧洲杯买球网站默塞德分校内华达山脉研究所所长.

“The big concern is how and where the transition from snow to rain occurs, 随着气候变暖，它将在何时何地发生, and what are we going to do about it as far as the changing water cycle,贝尔斯说.

自2004年以来, researchers from UC Merced and other UC campuses have used satellite data, modeling and on-the-ground observations to take precise measurements of the snowpack, giving scientists a better picture of how much water is in the Sierra.

“We’re finding that more of the runoff comes from the higher elevations and there’s more snow at higher elevations than previously thought,贝尔斯说, “which is good for water supplies because it’s colder at higher elevations.”

那里有更多的水吗?

高海拔地区的雪不太容易受到全球变暖的影响, 但一般是不衡量的, and the research is finding new technology that can measure the amount of snow and runoff. The data help water agencies predict how much supply they will have, 这对加州的城市至关重要, 农场和整个经济, 包说.

“We’re providing a blueprint for a new water information system and for how to measure water supply and make forecasts in future,他说.