State engineers, USGS outline groundwater‑management process for Sand Hollow; petition filed to start plan

Teresa Wilhelmsen, Utah state engineer and director of the Division of Water Rights, and U.S. Geological Survey officials on Tuesday described the process for developing a groundwater management plan for the Sand Hollow area after a group of local water users filed a petition asking the state engineer to adopt such a plan.

Wilhelmsen said the meeting was intended as a kickoff to explain how the state would evaluate groundwater availability and involve the public. “We’re gonna talk to you about groundwater management plans and the request the petition that was submitted to the state engineer for the Sand Hollow area,” she said.

The petition triggered a statutorily prescribed process under Utah Code 73‑5‑15, Assistant State Engineer Jim Reese said, and the Division cannot regulate groundwater withdrawals in the area until it completes required studies, notices and public meetings. Reese described a groundwater management plan as a tool to distribute limited groundwater and, if necessary, to limit withdrawals by priority date when pumping exceeds the basin’s safe yield. “One way a groundwater management plan might be established is that the state engineer decides to do so,” Reese said. “...the state engineer is compelled to actually do a plan if one‑third of the water right owners in the groundwater basin request that the state engineer adopt the groundwater management plan.”

Reese and USGS presenters outlined existing information and knowledge gaps. Natural (pre‑project) recharge estimates for parts of the Navajo Sandstone on the Hurricane Bench range in the studies presented from roughly 2,000 to 8,000 acre‑feet per year, Reese said, while the Sand Hollow managed aquifer recharge project has produced annual artificial recharge values that are substantially larger in some years. The USGS deputy director for the Utah Water Science Center (identified in the meeting as Tom) described how reservoir operations, evaporation and direct groundwater recharge are accounted for and monitored. “When you start filling that facility, just think of it as like a bathtub that’s empty,” the USGS presenter said, explaining initially high recharge rates as the reservoir filled and the unsaturated sandstone column resaturated.

The USGS explained the monitoring network and modeling used to quantify recharge and system response. The agency has used water‑level measurements, tracer chemistry and a transient MODFLOW model calibrated to observations near the reservoir. The USGS presentation noted that the Hurricane Bench could theoretically store on the order of 300,000–400,000 acre‑feet under quasi‑steady assumptions and that about 200,000 acre‑feet of water has been placed in the subsurface through the project to date, based on the agency’s calculations.

Meeting participants asked whether stored water has been recovered and how reservoir recharge relates to naturally occurring recharge. Reese said recharge‑recovery permits are treated separately: holders may recover water they have stored under their permit, and those volumes are generally not included in the distribution calculations for other water rights. He also said the Division needs better, transparent data from the Washington County Water Conservancy District on how much the district has stored and recovered under its permit before any regulatory distribution would be imposed on other right‑holders.

Several attendees raised questions about how priority dates work, including whether older water rights that were never placed to beneficial use could trump current users. Reese and Wilhelmsen said statutory mechanisms—typically through court action—exist to forfeit unused rights after seven years or to lapse applications that were not diligently pursued; however, such remedies are separate from the Division’s groundwater‑management planning process.

The Division asked local users to provide data, participate in local advisory committees if they wish, and begin metering and reporting so the Division can reliably account for diversions and use. Reese said staff will refine the estimate of the basin’s safe yield, work with USGS to add monitoring locations this spring, and make conservancy district data available publicly.

The Division posted meeting materials and data on a Sand Hollow webpage and invited public comment through April 14; staff said they plan to return to the community around June with updated information. No formal vote or regulatory action occurred at the meeting—rather, the petition remains on file and starts the multi‑step planning, study and public‑notice process required by statute.

For more technical details, the USGS noted its published reports and the agency’s public dataset in the USGS publications warehouse and said model and monitoring reports are peer reviewed and publicly available.

The Division emphasized that developing a groundwater management plan will be iterative and data‑driven, requiring additional field work, metering, and public meetings before any curtailment or distribution by priority would be imposed.