The cost of adding new water supplies to support the growing number of taps in Douglas County (Colo.) and Denver's southeast suburbs could skyrocket 20 times higher in the next few decades.
The cost of adding new water supplies now runs roughly $24 or $25 per acre foot. By 2025, the cost could be more than $4,000 per acre foot.
Customers, on the hook for more and more $1 million wells drilling ever deeper into dwindling aquifers, could see their water bills rise from $600 to $800 a year to $3,000 a year or higher.
New sources of water are needed if Douglas County and Denver's southern suburbs continue to grow -- or the cost of water will rapidly price people and businesses out of the market. In addition, since water projects take a long time to build, meaning decisions must be made relatively soon.
That's the view of water experts who are working on a $1 million study on how to meet the long-term water needs of Douglas County and south-central Arapahoe County. The report is expected to be done next June.
The report, which covers the engineering and technical problems of shifting water from the Western Slope, through the Denver Water Board's system and into the southern suburbs, is only the beginning of what will be a thorny, emotional and highly political discussion.
Who uses whose water for what purpose at what price?
"No matter what we do, we have to introduce new water into the south metro area," said Peter Binney, a local water engineer and program manager for the South Metro Water Supply Study.
Binney spoke at a Nov. 13 meeting of the National Association of Industrial and Office Properties, a forum for local bankers, developers, investors and brokers involved in commercial real estate.
"Enjoy the water you're drinking now because it's not going to get any cheaper," Binney told the group.
While some water can be recycled, reused and conserved, ultimately new supplies are needed, and those supplies are likely to come from the snowmelt-rich Western Slope.
Taking part in the study are the Denver Water Board, Douglas County, 12 water districts and towns in the south metropolitan area and the Colorado River Water Conservation District, which represents Western Slope interests. The state also contributed money.
The goal is to get 30,000 acre feet of new water that can be reused -- in effect creating a new 50,000-acre-foot supply.
The heart of the problem is that many water users in Douglas County and the southern side of the city get their water from underground aquifers instead of from mountain snowmelt.
The snowmelt is replenished every year. The aquifers were built drop by drop over millions of years by rainfall seeping into the ground. Getting that water out of the ground is getting harder and more expensive every year.
Seventy percent of Douglas County's water comes from the aquifers; water levels in those aquifers are dropping at a rate of 30 feet to 40 feet per year, Binney said.
The number of wells needed to keep up with existing demand -- as well as all the new subdivisions and developments on the drawing board -- is rising exponentially, Binney told the forum.
And each well can cost $1 million to drill, paid for by customer fees.
"We know the water is there and we know the cost is going up, and we know it's in the near-term, 30 years," Binney said in a later interview. "It's not a 100-year problem. This says to the politicians that we need to do something now; we don't have the luxury of waiting a decade."
Getting water out of the South Platte River is almost legally impossible due to the state's "first in time, first in right" system of water laws, he said.
"If you didn't have a water right on the South Platte by 1870, you don't have a reliable supply of water," Binney told the group.
Building a new dam to store more of the spring runoff is a $1 billion project that would need to be built near Deckers, flooding Cheesman Canyon and storing enough water to meet the annual needs of 400,000 new residents of the metro area.
So the answer might ultimately be to divert more water from the Western Slope.
The two-year study is focused on engineering questions and costs associated with infrastructure, said David Little, manager of water resources for the Denver Water Board.
Can extra water in Denver Water's system, which by charter is intended for residents of the city and county of Denver, be physically sent into Douglas County and the southern metro area?
Can additional water be diverted from the Western Slope?
If it's a dry year and Denver Water needs additional supply to make up for the water sent to the southern suburbs, where will it come from?
Also on the list of questions is what will the Western Slope, which needs water for its own population growth, agricultural uses and recreation-based economy, require as compensation if its water is diverted to the eastern side of the Continental Divide?
Among the options being explored is injecting extra, unneeded water from Denver Water into the underground aquifers. The plan would essentially create a giant, underground dam to store water, Binney said.
Also among the options is having Denver Water supply Douglas County's needs directly all winter long to relieve pressure on the aquifers, Little said.
"If we meet their demands either through injections or directly, then when the runoff comes our dams are lower than normal so we'd be OK during the spring runoff. We've filled the hole and we're OK," Little said.
The question is what would happen during "dry years," which occur every 10 or 12 years, and the runoff didn't make up for the water diverted to Douglas County, Little said.
"They'd have to buy water rights or pay us, but that's still a question," he said.
Little said he was surprised by preliminary data in the study indicating that the number of wells needed to keep up with demand will rise so high so fast.
Little said the information indicates that in 30 years it will take 400 to 500 wells to supply the same amount of water as 17 wells do today.