Editors Note: This article was originally published in the Nov. 22 2023 issue of the Chronicle Progress. Some information may be outdated.
Regional water engineer warns county groundwater plan likely after UGS study
A new groundwater management plan is very likely speeding toward the Pahvant Valley, Millard County commissioners learned last week.
Terry Monroe, a regional engineer with the Utah Division of Water Rights, who’s in charge of the Sevier River basin and southern region, led a brief discussion about an impending report from the Utah Geological Survey.
The details he said he’s so far learned from those producing the report include data showing aquifers below Pahvant Valley, feeding groundwater to area farmers, are collapsing. He also shared that data appears to show ground subsidence of as much as two centimeters a year in the valley, which reflects the effects of long-term over-drafting of groundwater resources.
He predicted the report will trigger a series of public meetings early next year, followed by a new groundwater management plan from the state engineer’s office.
A draft of the UGS report should be completed by the end of the year, Monroe told commissioners at their regular meeting last Tuesday.
It has long been known more than 100,000 acre feet of groundwater is annually being pumped from Pahvant aquifers. The recharge rate, however, is only about 60,000 acre feet. This means between 40,000 and 50,000 acre feet of groundwater is being routinely mined in the valley every year. An easily visible effect of this overuse of groundwater is the near disappearance of Clear Lake in the last decade.
In the 1990s, an effort by the state engineer to enact a groundwater management plan met with so much political pushback from the farming community, it was never implemented.
The plan called for metering wells, appointing a water commissioner and shrinking the amount of irrigated land.
“The last time we met the public did not want us to move forward with metering,” Monroe told commissioners. “So we’ve basically been trying to control groundwater withdrawal by controlling acreage irrigated. The problem has not gotten any better, it’s gotten worse.”
Nearly three decades after having attempted a groundwater management plan, Monroe said researchers with UGS have much better tools at their disposal for mapping the valley’s aquifers.
In the 1990s the water rights division was paying NASA for satellite photos to determine the area of land under irrigation. Today, commercial software does the job better and with far clearer resolution. Also, new tools such as LIDAR, which stands for “Light Detection and Ranging,” provide more accurate measures of any detectable shift in the ground over aquifers.
“One of the things that has been developed is LIDAR radar. Where they can get very accurate measurements of ground subsidence. They’ve noted ground subsidence in our area. The study shows approximately two centimeters per year of ground subsidence. So our aquifers are collapsing. That’s all stuff that’s going to come out in this report,” Monroe said.
He added that all the basin’s maps will be digitized and overlayed on aerial photos, checking that groundwater rights are being beneficially used on the land area to which they were allotted.
“We’re going to have a much more accurate, clearer idea of what areas are being irrigated without a water right,” Monroe said.
Farming operations in east Millard County are the likeliest to be directly impacted by any new management plan, particularly near Flowell. West side farmers use surface water from the Sevier River to irrigate.
Monroe admitted he could not say what a new groundwater plan would entail, since the process is just starting with the new modeling by UGS, a project started two years ago.
Commissioner Trevor Johnson asked Monroe if he thought the state engineer would get more support from the public this time around.
“I am getting much more support for the idea of moving forward with this than I did 25 years ago. There are a number of people in the area that are pushing us hard to do something,” Monroe answered. “There are public agencies that are pushing hard for us to do something…support or not, it’s an issue that’s going to have to be addressed.”
Commission chair Bill Wright made a comment that public officials up north might be interested to learn if there’s any available water in the Pahvant Valley, perhaps that being the reason for the burst of interest.
“That’s a lot of motivation behind them,” he said, before adding with a chuckle, “Maybe that’s wrong.”
Wright said his biggest concern was ensuring the property rights of land owners throughout the process.
Monroe said he couldn’t comment on the “intent of the legislature,” but said the reality was simply that there is more water being taken out of the aquifers than there is recharge going into them.
Responding to a question from Commissioner Vicki Lyman about state funding for farmers installing meters, Monroe suggested one culprit, an area of concern at least, were supplemental water rights—how they were obtained and how they are utilized.
“That’s the ball of twine we’re going to have to unravel,” he said.
State law requires any water right holder to measure the amount of water they are using. “Groundwater’s kind of had a pass in the past. Anything approved nowadays requires meters,” he said. “The trouble with meters is it requires somebody to read them, something to do with the data. Those are issues that would need to be discussed in the future in public meetings and things like that.”
He said the template the state engineer would likely pattern any new Pahvant Valley groundwater management plan would be those already in place in Parowan Valley or Beryl-Enterprise.
Monroe said he expects public meetings to start early next year, first with UGS showing the public the data it gathered, then later with the state engineer, including multiple efforts to gather public comment.
“We will present the findings of that study. We will have the authors of the study here to answer questions from the public,” Monroe said. “Hopefully we can work together to come up with a solution to the problems we have.”
