The United States Geologic Survey has released some preliminary numbers on the amount of groundwater being drawn from the Hualapai Basin aquifer.
The study shows that high-volume agricultural water use has increased in large amounts in recent years.
In 2014, agricultural use was about 8,000 acre feet, according to Jamie Macy, USGS supervisory hydrolgost at the Arizona Water Science Center. That number grew to 23,000 acre feet in 2015, and 32,500 feet in 2016, Macy said.
“There are projections that potentially agriculture water use could grow to as much as 100,000 acre feet of water use in the future,” Macy said.
The multi-year study, which is being funded by Mohave County and the City of Kingman, at a cost of about $460,000, will establish accurate measurements of water withdrawals in the aquifer.
“Although Havasu is removed from this issue that doesn’t mean they shouldn’t be interested because anything that has a financial impact affects the county,” said Michael Hendrix, county manager. “The cities are sisters in this together, and Mohave County is fighting water issues on a lot of different fronts.”
Last year, the county contracted with Phoenix-based HighGround Inc. at a monthly fee of $12,000 to provide lobbying efforts to state legislators on groundwater and Colorado River issues.
Although $200,000 has been budget for fiscal year 2018 for professional legal services, if the county decides to fight for its water rights in court it could be much more costly, Hendrix said.
“It’s not cheap,” he added. “You’re talking about hundreds of thousands if we litigate. There are things Mohave County is looking at and all of it costs bucks.”
The latest USGS monitoring of the Hualapai Basin began in April 2017, with completion scheduled for March 2019 and a final report in 2020.
The objective is to assess the impact on what is legally being taken from the groundwater reserves, Macy said. “In the Hualapai Basin right now we are in a net deficit of greater than 5,600-acre feet of water per year being pulled out of storage that is naturally in the basin,” Macy said.
To determine an accurate picture of what is happening, the Arizona Department of Water Recourses, through a watershed initiative program, has conducted a number of USGS studies since 2007.
The studies have produced a model of what was is happening in Mohave County’s aquifers and laid the foundation for a more refined model that the federal agency is currently working to develop.
In 2011, USGS study identified three major aquifers surrounding Kingman including the Hualapai, Sacramento and the Detrital Valley aquifer basins.
“The previous model was fast and lean, providing a two dimensional picture of what was happening with limited forecast ability,” said Jake Knight, USGS hydrologist. “That’s why we are rebuilding it, because the model is a simplified representation. A 2D model was well and fine for understanding the properties of the aquifer and matching the levels over previous decades.”
The new model will be very specific in its usefulness to forecast what could happen based on various scenarios, Knight added.
County consultant and former county Development Service Director Nick Hont said he is excited about the development of a more useful groundwater model.
“What we will get out of the USGS study will be tremendous,” Hont said. “It will answer most of the questions we don’t know today like how many years of water we have, and what do we need to do to protect that supply.”