Division of Water Rights opens Sand Hollow groundwater-management planning after water‑user petition

The Utah Division of Water Rights said a petition from water users has started the formal process to consider a groundwater management plan for the Sand Hollow area, Division officials told attendees at a public meeting. The petition — filed by more than one‑third of water‑right owners in the basin, Division staff said — triggers steps under state code the agency cited as “73515 of the Utah code.”

Division officials said the plan, if adopted, would be a tool to distribute groundwater in an orderly way and could lead to limits on withdrawals where pumping exceeds the aquifer’s sustainable supply. "We had a group of water users come together and petition the state engineer to to create a groundwater management plan. And so that's what initiated this process," Assistant State Engineer Jim Reese said at the meeting.

The plan area under consideration is bounded roughly by the Virgin River on the north, the Hurricane fault on the east and the extent of Navajo and Kayenta geologic formations to the south and northwest, presenters said. The Sand Hollow reservoir and its managed‑aquifer recharge (spreading) operations lie at the center of the area under review.

Why it matters: A groundwater management plan can limit withdrawals by priority date — “first in time, first in right” — if pumping is judged to exceed the basin’s sustainable yield. Reese said the state engineer may adopt a plan on the agency’s own initiative or after a qualifying petition from water‑right owners. He told the meeting domestic wells and other uses have no statutory priority and could be curtailed if curtailment by priority becomes necessary.

Estimates and current data: Reese summarized existing estimates of natural recharge for parts of the Sand Hollow/Hurricane Bench area at roughly 2,000 to 8,000 acre‑feet per year, a range Division staff called broad and in need of refinement. Reese and USGS presenters stressed those natural‑recharge estimates do not include the large volumes of water that enter the aquifer from Sand Hollow reservoir operations.

Tom, identified at the meeting as the deputy director for the USGS Utah Water Science Center, described monitoring and modeling of the managed aquifer recharge project. "The reservoir was purposely put atop the Navajo sandstone, knowing full well that the reservoir would leak, significantly and recharge the underlying aquifer," he said. USGS figures shown at the meeting indicated reservoir inflows, evaporation and groundwater recharge vary year to year; in some years measured inflow to the aquifer reached into the tens of thousands of acre‑feet while evaporation reduced the fraction that actually reaches groundwater.

Modeling and storage: USGS presenters said their Modflow model is well calibrated near the reservoir and is used with a network of monitoring wells and tracer analyses to track reservoir water moving into the aquifer. The USGS estimated the Hurricane Bench could store on the order of 300,000–400,000 acre‑feet in a quasi steady state and reported that about 200,000 acre‑feet have gone into the ground to date. Model particle tracking suggested an individual molecule of reservoir water could take on the order of hundreds of years (estimates cited in the meeting were roughly 500–800 years) to transit through the full aquifer; however, USGS staff emphasized that the hydraulic pressure response to the reservoir is much faster and can raise water levels across a wide area in a short time.

Process and data needs: Division staff said the groundwater‑management planning process will require additional scientific study, expanded water‑level and meter data, and repeated public meetings and notices defined in state code. Reese said the Division is working with the USGS and the Washington County Water Conservancy District to add monitoring locations and to obtain and publish operation and storage data from the conservancy district so the public and stakeholders can review it.

Legal and practical points reported at the meeting: - The Division cited "73515 of the Utah code" as the statutory framework the office is using for groundwater management plans. Reese said the state engineer "shall adopt" plan language becomes operative if the petition threshold is met. - Reese said recharge‑recovery permits (for stored water) are treated separately: holders of recharge‑recovery permits are entitled to recover water according to their permits and those recoveries are not part of the distribution cuts the Division might impose under a management plan. - An audience participant asked about nonuse forfeiture; Division staff and attendees noted that forfeiture for nonuse can be pursued in court and that a commonly cited interval for statutory nonuse is seven consecutive years.

Public participation and next steps: The Division posted meeting materials, the petition and related studies on a Sand Hollow web page accessible via a QR code distributed at the meeting. Division staff asked for public comments (the Division stated a comment deadline of April 14) and said the agency plans to hold follow‑up meetings — staff suggested returning to the group around June to present additional data and refine the safe‑yield estimate. No regulatory limits or curtailments were adopted at this meeting; staff said the meeting was a kickoff to collect data and stakeholder input before a draft plan is prepared.

What was not decided: Division and USGS staff repeatedly framed the meeting as informational; they said no formal groundwater‑management rule, curtailment or allocation change had been adopted. Any future plan would be subject to the administrative process and to judicial review, they said.

The Division said staff would remain available after the published session to take questions from attendees and encouraged water users to sign in to receive future notices and to submit technical data and comments for the record.