A new water study could show Star Valley has enough water to support five times its current population, although the town’s general plan draft states it doesn’t want to grow anywhere near that size.
A water study done two years ago by Payson, estimated the Star Valley area’s water supply could handle almost 22,000 residents. More recently, a town consultant thought it is more like 11,000. Either way, the town wants a new water sustainability study completed to determine the amount of water available so it can complete its general plan.
After a laborious two-year effort to create the general plan, it will take at least four more months to complete the study.
The town is conducting an independent water study because of concerns a 2006 safe yield water study by Clear Creek Associates inaccurately reported the amount of available water in Star Valley. Payson paid for that earlier study.
Star Valley recently received a $35,000 grant from the Water Infrastructure Finance Authority to fund its own water study by LFR Environmental Management & Consulting Engineering, a hydrology firm.
The study assesses the amount of groundwater that is usable without negatively affecting the town’s aquifer. Results are scheduled for late December 2008.
Town Clerk Sarah Luckie said the information from the Clear Creek study was used in a draft of the general plan, but the planning team did not agree with the synopsis given, so it halted the plan for more data. Star Valley’s plan has been in the works for the last two years as a board of more than 10 community members worked to figure out the best way for the town to develop over the next 20 years.
“The evidence we had at that point was either so old or from the Payson people, which we did not agree was a good look at the area,” Luckie said.
In 2006, Payson paid $50,000 for a water study by the Scottsdale-based hydrology firm, Clear Creek Associates. The company was asked to perform tests on the wells in Star Valley to determine if Payson’s usage of the Tower Well would affect the surrounding water supply.
Star Valley incorporated in 2005, shortly after a developer bought property in the town, including the Tower Well with its 400 gallons per minute capacity. Payson then purchased the excess capacity of 130 gpm from the developers for $750,000.
Star Valley residents worry a major pumping station would deplete the town’s water supply.
The Star Valley Watershed Safe Yield study stated that it is possible to capture 4,300 acre-feet of groundwater from the area without causing long-term declines in water levels, based on the average rainfall of 20 to 22 inches a year.
Safe yield is the amount of water that can safely be extracted each year from the aquifer. It is obtained by averaging rainfall totals over a 50- to 100-year period.
According to Clear Creek, a reliable safe yield for Star Valley is 3,440 acre-feet per year or 80 percent of total rainfall for the area.
Consultant Peter Armenta, community development director for Central Arizona Association of Governments, estimated at a July 28 general plan meeting that the safe yield is 430 acre-feet lower than Clear Creek estimates.
“In an effort to be conservative, this discussion will assume that a safe yield would be 70 percent, or 3,010 acre-feet,” the general plan states.
Armenta put the general plan together for the town.
Based on the annual recharge and an area’s water use of 200 gallons per day, the town could handle more than 11,000 residents, Armenta estimates.
The Clear Creek study assumes the town has more water available and residents use less water per day, which would mean the town could handle roughly 22,000 residents.
The general plan draft states that the town should not grow beyond 4,000 residents to retain its rural atmosphere.
The new study will either confirm or disprove the Clear Creek Associates and Armenta’s estimates on the volume of water storage and provide recommendations on the aquifer’s capacity to sustain growth in Star Valley. Once the study is released, the general plan will head back to the planning committee who will pass it on to the council and finally to the public for approval.