BOISE, Idaho — Federal scientists are conducting a low-flow stream study in six Western states in an attempt to gain insights that could help resource managers better allocate scarce water supplies during future droughts.
U.S. Geological Survey workers are measuring flows and temperatures through September in nearly 500 streams mostly in upper tributaries in Idaho, California, Nevada, Oregon, Utah and Washington.
The report could ultimately be used for everything from deciding how much water to release from dams, how many cattle to allow on grazing allotments, how much water will be available for farmers in irrigation districts and decisions about rivers that contain fish protected under the Endangered Species Act.
“If water managers can understand which streams are most vulnerable it helps them target efforts for drought relief,” said Chris Konrad, a research hydrologist with the federal agency and the study’s project chief.
The spring snowpack in the West in 2015 was much lower than long-term averages, and many rivers in the region are now at historically low flows.
What is especially unusual about the low snowpack, Konrad said, is that many areas received average amounts of precipitation. However, it came down as rain rather than snow, meaning it immediately ran through basins rather than forming a high-elevation snowpack that functions as a kind of reservoir slowly melting through the summer to replenish streams.
“This is pretty extreme by historical standards,” Konrad said. “I don’t know that we can expect this kind of year frequently. But at the same time, we also know climate models are telling us we should expect warmer winters and in some years less snowpack. If we see one year like this, it’s likely that we’ll see more years like this.”