New reservoir approved in Mountain Green

Morgan County Commission has approved a conditional use permit for the 14-acre-foot secondary water regulating Nettleton Cobble Creek Reservoir which would be located about 3,000 feet southeast of Mountain Green Elementary School. The reservoir is needed to provide sufficient water pressure for the Cottonwoods development. Two phases of that development do not have the required water pressure because of their elevation and a reservoir is an allowed use in that zone, Morgan County Planning Director Josh Cook told the county commission on July  2.

“It will initially serve as a pressure regulating reservoir to provide up to 72 hours of water storage and head for pipeline pressure for properties in the upper-pressure zones of the Cottonwoods and properties adjacent,” the application said. “Based on the geotechnical report from the tank project the soils are ideal for construction of a native clay reservoir, but to avoid seepage losses we will most likely install a black HDPE liner.” 

The developer also plans to create a separate 4-acre parcel to eventually transfer title for this reservoir to Durst Water Company or another water distribution company for operations and management, it went on to say.

The Mountain Green Secondary Water Company which owns the 40-acre foot Cobble Creek Reservoir in Mountain Green just below the proposed reservoir sent the county a letter expressing concern about this reservoir in the same drainage area.

“MGSWC is concerned that 1) the proposed Nettleton CC Reservoir has the potential to impact the MGSWC Cobble Creek Reservoir and downstream homeowners negatively; and 20 the application is incomplete because the County Engineers memo states that the application is ‘…insufficient for our review,’” it said.

It went on to say, “MGSWC’s understanding is that the applicant has not yet obtained either water rights or dam safety approval for the proposed Nettleton CC Reservoir. MGSWC encourages Morgan County to require the applicant to secure all necessary State permits particularly an Order to Construct before Morgan County issues a CUP. We believe this additional State review will assist Morgan County in identifying and addressing reasonably detrimental effects of the proposed Nettleton CC Reservoir and in answering important questions related to the reservoir’s construction and its impact on adjacent landowners.”

Commissioner Blaine Fackrell expressed concern that this reservoir not impede any water users below it.

“They’re going have to go through design with the state engineer; they're also going to have to go through site plan review for us and provide all those certifications and show how they're designing it,” Cook said in response. 

Under state statute the commission cannot deny a conditional use permit for something that is an allowed use in a zone but can ensure that negative impacts are mitigated by conditions it imposes on the applicant, Cook said after commissioners expressed concern about allowing this use before seeing any design specifics. 

“[With] a conditional use permit just because you grant it doesn't mean that they can build it,” Commission Chair Mike Newton said. “They've still got to jump through an awful lot of hoops before they can get there.”

The commission postponed its decision from that meeting until its July 16 meeting because the applicant was not present. Developer Ray Nettleton attended that meeting and addressed their concerns.

Although the proposed reservoir would be above the Cobble Creek Reservoir the assistant state engineer Albert Taylor “indicated that the dam would be classified as a low hazard due to the fact that any dam breach would continue downstream into the Cobble Creek Reservoir which has enough free board volume to contain the entire 14 acre-feet of this proposed reservoir,” he said, “So that I think that demonstrates that it's our little Reservoir is not going to impact the larger reservoir downstream.”

Nettleton plans to build a diversion structure so that all the drainage from a seasonal stream in the areas would flow through an engineered channel and bypass the reservoir and water would be pumped to the reservoir from lower elevations, he said. “We don’t collect any water unless we’re authorized by our water rights.”

Taking the concerns of the Mountain Green Secondary Water Company letter into consideration, and after hearing from Nettleton, the commission approved the application with the following conditions: that it be surrounded by a galvanized chain-link fence; that Nettleton has a geotechnical investigation completed; that he improve the access road to allow for emergency services access; that the disturbed area be reseeded with native plants to help control erosion; that the reservoir comply with Utah Division of Dam Safety regulations; that the reservoir its fencing and erosion control be maintained and inspected re3guarlty and that Nettleton obtain state certifications, state engineer approval and the required water rights which he will need to present at site approval.

Last year the developer also applied for a conditional use to build a water tank. That application was approved, and the tank is in the site plan process.

“When the demand comes we'll complete the site plan; we'll re-engineer the site plan and make sure it works with the reservoir and the road works,” Nettleton said. λ