This story first appeared in Colorado Community Media’s newspaper. The Colorado Sun is the owner of CCM.
An average of 25 people move to Douglas County every day. Everyone needs to drink water, shower, water the lawn and wash the dishes.
The full impact of this growth is hard to see, but easy to understand: More people need more water. In a county where thousands of households depend on a limited supply of underground aquifers, water providers have struggled to switch to more sustainable sources before they run out.
Some aquifers below Douglas County have lost 2 to 6 feet of water. Local water suppliers have noticed that their water wells are not as productive as they used to be.
“It’s like sucking water out of a bathtub with a straw,” says Rick McLoud, water manager at Centennial Water & Sanitation. “There’s only so much water in the tub, and the sooner you get it out with a straw, the quicker it goes away.”
Centennial Water, which provides water to about 100,000 customers in the Highlands Ranch and Mirabelle communities, is a supplier in Douglas County that noticed a drop in well production.
The water they pulled to the surface was drying up. And it doesn’t replenish itself.
The county is expected to continue to grow, with nearly 60,000 people expected to move to the area by 2030, according to the state’s Population Office. This means that the desire of the community will only increase.
To meet these needs, water providers are planning a range of conservation efforts, wastewater projects and new infrastructure for renewable water resources. The county is also looking at how to bring in more water and is considering taking some of its $68 million in federal funding out of the US Rescue Programs Act to address the problem.
over-reliance on groundwater
Douglas County has grown rapidly since the 1990s, and many of its largest communities, such as Parker and Castle Rock, rely on groundwater to fill residents’ bathtubs and sinks, said state engineer Kevin Rein.
In Colorado, the Office of the State Engineer administers water rights, manages wells and their permits, and monitors water use, among other water-related duties.
Groundwater from aquifers accounts for approximately 65% of the water used by Parker Water and Sanitation (part of Parker and Lone Tree and Castle Pines suppliers) and Castle Rock Water. Centennial Water uses approximately 20% of groundwater. These ratios may vary depending on drought conditions.
Douglas County has about 440 municipal wells that draw water from aquifers, according to the state engineer’s office.
“Douglas County is unique in that its over-reliance on groundwater in some ways has damaged it because we are not as affected by the hydrological cycle as other areas,” said Brock Smethills, president of Sterling Ranch Development Company. Board member of Dominion Water and Sanitation, a company serving northwest Douglas County.
That’s because regions that rely on renewable surface water and snowmelt will feel the effects of dry years more strongly.
A simulation conducted by the USGS shows that from 1880 to 2003, about half of the water withdrawn from the Denver Basin aquifer came from the southern Denver metro area, said Suzanne Paschke, associate director of hydrological research at the Colorado Water Research Center. USGS Science Center.
“According to our simulations, this is where most of the storage depletion in the basin occurs,” Paschke said.
Aquifers are drying up
Since 1996, the state engineer’s office has been advising those using wells in the Denver Basin to be aware of the limited amount of water in the aquifer, Rein said.
“We recognize the non-renewable nature, and we’ve advised … anyone using this resource should recognize that it’s non-renewable, and it may not even last 100 years after it’s been allocated,” Rein said.
In 2003, news reports said the aquifer was declining to the point that some parts of the county could run out of groundwater within 10 to 20 years.
Studies completed by the US Geological Survey in 2011 and 2019 showed that the decline of the aquifers continued, but made no predictions about the amount of time until they became empty.
“We can pump out less now than we did when we started,” said Centennial Water’s McLoud. “We’re feeling the limits of it.”
Castle Rock water director Mark Marlowe said many of the city’s wells had seen water levels drop, but added that it was difficult to determine how widespread the withdrawal was in the watershed.
“There’s a lot of supply, but in the long run, it’s going to be more difficult to extract the supply,” Marlow said. “Frankly, we want to protect this supply during times when surface water is not available.”
The added difficulty is because as water levels in the aquifer drop, more wells must be drilled to maintain the same production, resulting in increased costs.
Castle Rock is currently working with Colorado State University to study their deep groundwater, Marlowe said.
“There’s still a lot to learn and understand in terms of how long the Denver Basin groundwater can be sustainable as a resource,” he said.
Parker Water and Sanitation regional manager Ron Redd said from their well monitoring they were also seeing declines in multiple aquifers.
“On average, we could see a drop of 2 to 6 feet,” he said.
Douglas County sits on multiple aquifers, including the Arapahoe, Denver, Dawson, and Laramie-Fox Hills aquifers. Most major water suppliers use water from the Arapahoe and Denver aquifers, which are 1,700 feet and 600 feet below ground, respectively.
“While the aquifer there is thicker, I think it’s used so much that it’s seriously affected,” Pashcke said.
To read more of this story, visit douglascountynewspress.net