La Plata County may be taking a major step in understanding its groundwater system.
In April, the Colorado Geological Survey nominated La Plata County to be the focus of a comprehensive groundwater study that would, essentially, fully document all the underground waterways and aquifers in the county.
The Colorado Water Conservation Board is expected to make its decision in June, which would approve a $50,000 grant to fund the study. The Colorado Geological Survey would then match that amount.
The completion of a comprehensive groundwater study would be a benefit in understanding water resources in the county and serve as a tool for planning for future growth, county officials say.
“Most of our development in the unincorporated areas of the county rely on groundwater,” said La Plata County spokeswoman Megan Graham. “Having a complete understanding of where water is available would be incredibly helpful.”
Peter Barkmann, a senior hydrologist with the Colorado Geological Survey, said the study would take about two years to complete. La Plata County was considered for the study, he said, because of the expected population growth that will put an increased demand on water resources.
“Since there’s been a lot of growth, people are realizing how important groundwater is as a water source,” Barkmann said. “And counties are seeing a lot of growth spread out into more rural areas that are going to put a lot more dependency on groundwater.”
Most of the work in drafting the groundwater maps relies on compiling existing information, through sources such as the Colorado Division of Water Resources or well drilling businesses, which are required to file reports on groundwater.
“We do a little on-the-ground work if we need to, but these maps for the county are mostly a compilation of existing data,” Barkmann said. “And they’re pretty accurate because we bring data from a number of sources.”
As it stands, developers who propose a project in La Plata County are required to drill a well, and to build, the well must produce a minimum amount of water. But the process is expensive and carries some uncertainty if the well doesn’t produce.
La Plata County Planning Director Jason Meininger said the biggest concern the county hears from neighbors when a new development is proposed is if the project will affect their existing well.
“If the county had a better understanding on how the groundwater flowed and how much is available, it would hopefully address some of those questions up front,” he said.
Right now, the county doesn’t have a good grasp on how much water lies beneath the surface, or where, Meininger said.
La Plata County doesn’t have typical aquifers like other places. Instead, there are more braided, subterranean watercourses, which causes water wells – even in close proximity – to have major differences in quantity and quality.
Lacking this information makes it hard to assure neighbors that their wells won’t be affected by development, Meininger said. And the county doesn’t have a system in place to take into account the cumulative impacts of smaller developments.
“Hopefully, this study will help inform that,” he said.
Aside from development putting pressure on groundwater, the changing landscape of La Plata County, where more and more agricultural lands are being sold off for development, is causing wells to dry up.
“A lot of those properties being developed were irrigated agricultural lands,” Meininger said. “So two things are happening: The groundwater recharge is reducing as those lands are taken out of irrigation, and the groundwater uptake is increasing with more development pressure.”
In an attempt to get a better sense of how many wells are drying up, the county is developing a web-based tracking system where people can report when their wells go dry.
“We’re hearing an increasing number of people are having their wells go dry, and we’re hoping this puts numbers behind that,” Meininger said.
In other counties across Colorado, the hydrology study has been a great benefit.
In Park County, for instance, the study has helped track where water is, and just as important, where water isn’t, said County Manager Tom Eisenman.
“We have better data now than we did before to look at what the water source availabilities will be within those areas where further development will potentially happen within the county,” Eisenman said.
Eisenman said he has heard of developers using the maps before proposing a project. Like La Plata County, Park County is experiencing growth in areas that were historically used for agriculture.
The study also revealed important information about water quality. Planners now know if they drill too deep, they’ll expose water that has a high saline content.
“We now have a better road map,” Eisenman said.
In all, eight counties in Colorado have had a comprehensive groundwater study done by the Colorado Geological Survey.
“It’s good to have all this information together,” Barkmann said. “Especially in counties where important decisions are being made.”
jromeo@durangoherald.com
