Southern Utah city says it needs a $22M reservoir or development will have to stop

Washington County water manager issues warning to Ivins elected officials, residents.

Ivins • If plans to build Dry Wash Reservoir in Ivins are ditched, the Washington County Water Conservancy District will not be able to fulfill its contractual obligation to supply water to the southern Utah city.

That’s the alarm Zach Renstrom, general manager of the district, sounded Wednesday evening at a public meeting on the $22 million reuse reservoir planned for 90 acres in west Ivins between Kwavasa Drive and Highway 91.

Moreover, he added, that would only signal the beginning of the city’s problems. For starters, the district would have to huddle with city officials to discuss when they might implement a moratorium to stop any further building.

Since Ivins has already approved a lot of new permits for construction, Renstrom said that would put city officials in the unenviable position of having to tell developers they couldn’t proceed as planned to build the agreed-upon number of homes.

“They will get sued …,” Renstrom told the crowd that packed Rocky Vista University. “I will guarantee I’ll be the first one on the stand and they’ll ask me the question, ‘Could you have got water to Ivins city? And I [would say] ‘Yes, we have a plan [for a reservoir] that had been approved by multiple engineers. It’s a plan that had gone through environmental analysis. But we were not able to build that because the city said we weren’t [able to]. So therefore I can’t fulfill my contractual obligations [to Ivins].’”

Ivins dependent on district water

Currently, Ivins gets about 80% of its water supply from the district. Renstrom noted the city’s own water supply ran dry long ago. “But you are still able to grow today because you are getting water from the water district,” he said, adding a lot of the city’s water is currently coming from Sand Hollow Reservoir, Snow Canyon and St. George.

Dry Wash Reservoir, along with Graveyard Wash, a reuse reservoir planned for the Santa Clara area near Highway 91, is key to the water district’s plan to secure another 47,000 acre-feet of water by 2042 to keep pace with growth. By storing treated wastewater that could be used for outdoor irrigation, the reservoirs would free up culinary water to be used to supply new homes.

Doug Bennett, the district’s conservation manager, said implementing stricter conservation measures would account for about 11,400 acre-feet of the 47,000 acre-foot total. Most of the balance is projected to come from 100 projects — including a regional reuse water system — the district plans to build at a combined cost of more than $1 billion, most of which would be funded by impact fees.

(Mark Eddington | The Salt Lake Tribune) Washington County Water Conservancy District general manager Zack Renstrom talks about the importance of Dry Wash Reservoir at a public meeting Wednesday, Feb. 21, 2024, at Rocky Vista University in Ivins. Ivins Mayor Chris Hart is seated onstage to Renstrom’s right.

In its current configuration, Dry Wash Reservoir would hold 1,500 acre-feet at its fullest point and be drawn down to a conservation level of 300 acre-feet during the hot summers when the water would be distributed to areas as needed.

During dry years, according to the district, the St. George wastewater plant would pipe treated reuse water to Dry Wash for storage. In wet years, the reservoir would store water from Gunlock Reservoir, which could then capture and store more spring runoff from the surrounding mountains. Without a place to store reuse water, the water would be discharged into the Virgin River to flow downstream into Lake Mead.

Residents not sold on Dry Wash

Still, many residents at Wednesday’s meeting were not sold on the merits of locating a storage reservoir in the middle of a fast-growing residential community. Chief among their concerns is that when Dry Wash’s water levels are lowered during hot summer months, it would expose much of the lakebed to high winds they argue could blow dust clouds across Ivins and neighboring Santa Clara.

Ivins resident Wayne Pennington, a geophysicist and retired dean of engineering at Michigan Technological University, addressed the dust issue in a short video presented at the meeting. He noted the water district’s current design for Dry Wash calls for a reservoir with a high-water elevation of 3,044 feet above sea level, four feet higher than the amount specified in an Environmental Assessment conducted in 2004.

Pennington said the current design would expose 47 acres of lakebed during the summer, resulting in “areas muddy with bugs or dry with wind-borne dust.” By way of contrast, he explained, that exposed lakebed would be larger than the entire 37-acre surface area of nearby Ivins Reservoir.

“Just imagine an area one and a quarter times that of Ivins Reservoir drying up [and] blowing dust from reuse water inside Ivins city next to residential areas,” Pennington stated in the video.

To reduce the size of the exposed lakebed and potential for dust clouds, gnats and other negative impacts opponents have expressed concerns about, Pennington is proposing a smaller reservoir with a high-water elevation of 3,038 feet. Unlike the current iteration for the reservoir, his design would not include a 66-foot dam that critics argue could leak or overflow and pose a risk to nearby homes.

“These problems may be reduced, although not eliminated, by lowering the height of the proposed reservoir … ,” he asserted in the video, adding “Ivins will need to address these issues before approving the reservoir.

District officials and their engineering consultants countered Pennington’s suggestion for a smaller reservoir, arguing that cutting the size of the reservoir would significantly reduce its carrying capacity. Moreover, they added, independent experts and dam safety experts with the state Division of Water Rights have reviewed and signed off on the dam in the current design for Dry Wash.

Renstrom said the district has already spent considerable time and money exploring possible alternative locations to Dry Wash for a reservoir, none of which panned out. As for those who want Graveyard Reservoir built first to give opponents more time to explore alternatives to Dry Wash, Renstrom said a track from a Mojave Desert Tortoise, which is listed as a threatened species under the federal Endangered Species Act, was recently discovered at the Graveyard location, which has complicated plans for that reservoir.

If Dry Wash Reservoir is built as planned, the district will be responsible for all operation and maintenance costs. Ivins has agreed to pay for dust mitigation and dealing with insects should problems arise. Before assuming that obligation, though, Mayor Hart said the city will hold several work sessions open to the public where elected officials can hear from experts about the reservoir and its perceived risks, address concerns raised by opponents and discuss the city’s options.