Sunday, July 30, 2006 | 7:39 a.m.
Water-system managers on the Colorado River had high hopes for high water at the beginning of this year.
Those hopes, like the snow on top the Rocky Mountains, are rapidly evaporating. The critical April-through-July runoff period in the mountains, which provides most of the water going to the river, is more than 25 percent off the average. The disappointing results make this the sixth year of the last seven in which flows were significantly below average.
"We still have a couple of weeks, but it looks like it is going to be a little disappointing," said Colleen Dwyer, a federal Bureau of Reclamation spokeswoman. The bureau is the manager of the lower basin of the Colorado River, including Lake Mead. Las Vegas and suburbs get more than 90 percent of their drinking water from Lake Mead.
Water managers and scientists earlier this year had predicted near-average runoff. Hopes were particularly high because the previous year had spectacular snowfall in some areas that at least temporarily reversed five crushing years of drought.
"Around about April or March, it was looking like another decent year," said Kelly Redmond, regional climatologist with the Desert Research Institute's Western Regional Climate Center in Reno. "Runoff was looking at being close to 100 percent. But we got warmer temperatures and less precipitation, not dramatically so, but still it was considerably drier and warmer than usual. Both those things hastened the demise of the snowpack and sent it up to the atmosphere rather than into the Colorado River."
Redmond said climatologists and meteorologists are looking carefully at the forces that drive Western weather in the winter, but so far the evidence is still ambiguous on how much precipitation is to come.
The critical issue of Pacific Ocean temperature and especially the El Nino warming in the central ocean hasn't yielded strong evidence so far, he said.
So far, scientists see a weak El Nino, and a weak system doesn't help them predict the amount of rainfall to come.
Redmond and the federal National Oceanic and Atmospheric Administration agree that the fall should be a little warmer than normal, with an equal chance of precipitation above or below average.
"The year so far is trending toward the warm side," Redmond said. "That could continue into the winter as well."
The warmer temperatures could mean that precipitation, when it does come, would come more as rain, less as snow. That's bad news for water-systems dependent on the Colorado River because rain evaporates more quickly and puts less water into the river.
Ken Albright, resource director of the Southern Nevada Water Authority, water wholesaler for most of Clark County, said there is some good news in this water year, which officially ends Sept. 30.
"Upper basin reservoirs are in many instances now full," he said of the lakes high in the mountains. "That is a good sign for us."
He said water managers were pleased with the 2005 runoff but knew the situation could turn around quickly. "One good year did not take us out of drought mode," Albright said. "Until reservoirs are back again - well, really always - we have to treat the resources with the respect that they're due It is going to take many good years to reverse the effect of five or six years of drought."
The drought shows the importance of bringing in other sources of water to Las Vegas and of storing water for future use, he said.
The Bureau of Reclamation, the Water Authority and all seven states that share the Colorado River are working to devise a set of rules on how to handle long-term water shortages. Dwyer said the talks among the participants are on track to have the new rules in place by the end of 2007.
In the meantime, Lake Mead and the upper reservoir at Lake Powell will continue meeting the needs of users along the river, she said.
"It's grim, but as far as we can see we're certainly going to meet all the demand this year," Dwyer said.
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