With continuing population growth in Southwestern states and ongoing drought, water issues are becoming more and more about who has to cut back their use when there isn't enough to meet demand.
That thread ran through presentations at the annual Water Seminar on April 4 in Durango, sponsored by the Southwest Water Conservation District.
"How will we handle the water and other needs of 10 million people," asked John Stulp, a former state agriculture commissioner and current chair of the Interbasin Compact Committee (IBCC) which is developing a State Water Plan along with nine basin water roundtables.
The roundtables were set up by the Colorado legislature in 2005, Stulp said. Each roundtable has two representatives on the IBCC, which looks at water issues from a statewide perspective, he said. Area representatives on the IBCC are Southwest Water Conservation District Director Bruce Whitehead and water engineer Steve Harris.
Whitehead opened the day-long seminar by commenting that the State Water Plan "gives us something to argue about other than politics in an election year."
Stulp said the State Demographer predicts a state population of 10 million in 2050, about double the current population. Based on current water supply, pending water projects, and savings from conservation, he said the 2050 water supply shortfall is projected to be around 350,000 acre feet. (For comparison, Vallecito holds 125,000 acre feet.)
Whitehead said the IBCC is considering four strategies in the plan - conservation, development of projects already started, new supplies (meaning trans-mountain diversions from the West Slope to the Front Range), and "buy and dry" - buying up agriculture water rights for municipal use.
"The IBCC agrees the last one is least desirable," Whitehead said. As for trans-mountain diversions, the Southwest Water Roundtable is taking the position that "development of water within each basin should be a priority before looking anywhere else," he said.
Harris cited a statewide statistic that with municipal water use, half is used inside and half outside. Ninety percent of the inside use returns to the stream. With outside use, 70 to 80 percent is "consumed" and does not return to the stream. The Southwest Roundtable has approved a goal to shift the percentage of municipal use to indoor, especially where the water comes from ag dry-up or trans-mountain diversion, he said.
Harris initiated the idea of legislation to limit lawn sizes in residential developments after 2016 where the water would come from a permanent transfer from ag. It didn't get through the State Senate but will be a study topic by an interim committee on water resources during the off-session.
"The lawn bill, this is just the first time, not the last," Harris asserted. "Reduction of lawn size is a significant conservation measure to help meet 2050 water supply."
State Rep. Don Coram from Montrose commented "On the Front Range, they haven't addressed storage or depleting the aquifer. They are more interested in trans-mountain diversion."
A panel on Colorado River compact issues delved into the issue of whose water use will be cut back if there isn't enough to satisfy commitments for the Upper Basin and Lower Basin states and Mexico.
John McGlow from the Upper Colorado River Commission said curtailment such as this will affect water rights decreed after the 1922 Colorado River Compact. The Upper Basin is western Colorado, eastern Utah, southwest Wyoming, and northwest New Mexico. They have begun discussions on how cutbacks would be shared, or how to avoid getting to that point with things like fallowing fields and reducing frequency of irrigation.
"Lake Powell is our bank account for complying with the compact," he said. It's the cushion for the Upper Basin states to deliver mandated quantities of water to the Lower Basin states (California, Arizona and Nevada) and Mexico over a 10-year average. Navajo Reservoir also is part of that.
McGlow said 1999 was the last year that Powell was full. The goal is to get enough water into Lake Powell each year to avoid curtailment or the possibility of the water level getting too low for hydropower generation, which he said would have its own serious impacts.
The good news is there's enough snowpack in northwest and north central Colorado that these won't be issues this year, McGlow said.
Harris said, "There was a realization that during drought, there could be a compact curtailment." Most water diversions to the Front Range are post-compact, and about half of the post-compact rights on the Western Slope are municipal, he said.
"So there was the idea to sign up pre-compact rights to curtail, so post-compact uses could continue," Harris said.
Panelist Dan Birch from the Colorado River Conservation District said most pre-compact rights on the Western Slope are in the Grand Valley and Uncompaghre Valley. There is around 1 million AF of pre-compact irrigation on the West Slope, he said. Most of that land is in pasture or hay. Pasture can't be fallowed, he said.
With a target to make up for 350,000 AF of post-compact use, Birch said, "I don't think we want one-third of ag to go away. What we're talking about is interruptible voluntary market-based contracts" for pre-compact users to reduce their water use. "This has to work for the farmers and the ditch companies," he said.
Birch said power plants in Northwest Colorado are significant post-compact water users. "In the event of a (water) shortage, it will be important to keep critical uses going," including power generation, he said.
Demand management is a key to avoiding Upper Basin curtailment or loss of hydro generation. "We are way behind on actual implementation of demand management," including agricultural fallowing and reducing municipal demands, McGlow said. "It's still a concept. It's in its infancy."
Fallowing and reduced irrigation are part of what's called water banking. Panelist Aaron Derwingson said, "Pretty much everyone supports water banking in concept. It gets a lot more complex actually doing it."
Coram said, "I don't think water has politics. It's for all of Colorado. We all have an interest in this issue."