If population trends hold and the Treasure Valley gains an average of 1.9 percent more residents per year, the Boise area could be home to 1.6 million people by 2065. At the same time, climate models from the National Oceanic and Atmospheric Administration indicate a temperature increase in the Pacific Northwest of between 2 and 4 degrees Fahrenheit by 2050. Between 2021 and 2050 the region's temperatures are projected to increase 2.5 degrees; between 2041 and 2070, the region's temperatures are projected to increase by 4 degrees; and between 2070 and 2099, the region's average temperatures are projected to increase another 6.5 degrees.
In a new study from Boise-based SPF Water Engineering, presented to the Idaho Water Resource Board, a combination of population growth and climate change will result in startling demand for water—a possible increase of as much as 357 percent across the Treasure Valley.
The projection incorporates an estimated 10 percent increase in a long-term "precipitation deficit" resulting from higher evaporation rates fueled by warmer temperatures. Even taking into account moderate levels of water conservation, indoor use of water by residential consumers is projected to increase by as much as 61,300 acre-feet per year across the Treasure Valley.
No one is shouting "crisis" yet, but the study inspired us to talk to Brian Patton, board chief of the Idaho Department of Water Resources.
The bottom line of this report was jaw-dropping. What triggered this analysis?
Several years ago, the Idaho Legislature asked the water resource board to investigate potential water storage projects.
Can you name one of those projects?
We've been partnering with the U.S. Army Corps of Engineers to look at the Boise River. The Corps is interested in reducing our flood risk on the river, while we're interested in finding ways to better manage our future water supply.
Doesn't this analysis have a much broader applicability?
It definitely helps inform other water management decisions in the Treasure Valley.
The executive summary of the report said, "new supplies can be achieved through a combination of measures," such as improving water conservation and increasing groundwater pumping. Does that mean we could or should be pumping more groundwater than we're currently pumping?
In certain parts of the Treasure Valley, there is additional groundwater that could be pumped.
Canyon County. The aquifer is generally stable in Canyon County and can probably be utilized to serve future water supplies. The closer you get back upstream toward Boise, the aquifer is under more stress and probably couldn't withstand large additional uses.
The study also challenges more Treasure Valley communities to conserve water, indicating a number of towns or municipalities aren't metering their water customers. Can you tell me which towns or cities are not metering?
All the big cities do. A number of small towns don't meter. [A check of water providers across the Treasure Valley revealed residential customers of Capital Water Corp.—about 2,700 households near Capital High School—were not metered, nor were residential customers in Star or commercial customers in Kuna].
To be clear, the implication here is that metering all customers is a tool for water conservation.
Yes, moving away from a flat rate and toward metering all customers would have that effect.
>One final question of a more immediate nature: We're hearing water resources for the Treasure Valley this summer are looking good.
I think we'll have a good water year in southwest Idaho overall but, again, that's just for the coming year.