The ongoing drought has highlighted the need for increased water supplies in Oregon, but low soil moisture poses a major impediment to water storage, experts say.
Even if Oregon experiences healthy precipitation and snowfall in the future, it will take years to refill some reservoirs because water will first be absorbed by the thirsty soil, experts say.
“That’s the first place it’s going to go,” said Margaret Matter, water resource specialist with the Oregon Department of Agriculture. “Once you get the soils resaturated, there’s nowhere for water to go but down the channel.”
Soils dried rapidly in June, leading to an extremely low level of moisture before summer even began, said Scott Oviatt, state snow survey supervisor for USDA’s Natural Resources Conservation Service.
“We’re seeing conditions that are typical of July or August,” he said during a recent meeting of the Oregon Water Resources Commission.
Snow at the mid-elevation level, which is critical for stream flows, melted early in the year, he said. “What snow did accumulate was mostly at the higher elevations.”
The current “El Nino” cycle of warm temperatures in the Pacific Ocean is likely to persist through the coming winter, which bodes for more mild weather in the Northwest, said David Rupp, research associate at Oregon State University’s Oregon Climate Change Research Institute.
The situation would be aggravated if the “blob” of warm temperatures in the north Pacific—which deflected storms from the region—does not dissipate, he said.
There’s no evidence that El Nino cycles are more frequent due to increased greenhouse gases in the atmosphere, Rupp said.
However, it stands to reason that El Nino’s effects would be more pronounced if temperatures get higher, he said.
In some years, natural variability may counteract the overall warming trend, but in the long-term it’s unlikely the region will be getting more snow, Rupp said.
“The year we’re seeing this year, which is not normal, will be normal by 2050,” he said.
Source: www.capitalpress.com