CHANDLER — The Pinal Active Management Area has enough water for the county to grow, but steps need to be taken to make sure there is enough water in the long-term future, the three founding members of the Pinal Groundwater Task Force told a packed room of more than 100 members of the Pinal Partnership Friday morning.
“Our backs aren’t up against the wall yet,” said Pinal County Supervisor Steve Miller, who also serves as the task force’s chair. “We’ve got time to figure this out.”
“It’s not a simple yes or no answer,” said William Garfield, a co-vice chair of the task force and a senior adviser to Arizona Water Company. “It’s really a problem of how we commit that water for projects that need to have an assured water supply in order to move forward. There is a real need for more water.”
The task force was put together by the Arizona House Ad Hoc Committee on Groundwater Supply in Pinal County in October. The task force is charged with finding possible solutions to the county’s declining supply of groundwater.
The three leaders of the task force answered questions at the monthly breakfast of the public-private Partnership and gave a brief synopsis of the results of the new groundwater model for the Pinal Active Management Area that was released by the Arizona Department of Water Resources in October.
The model states that the area, which includes most of the county but not the northern part, does not have enough groundwater to supply its existing and future demands for the next 100 years. At the end of those 100 years, the county’s water supply will have fallen more than 8 million acre-feet short of the estimated 80 million acre-feet demand projected by the department, according to its estimates.
The problem with ADWR’s groundwater model for the Pinal AMA isn’t the data, the three task force leaders said. It’s how the data was used in the calculation of the model.
The model doesn’t take in some of the nuances of the water situation in the county, Garfield said.
The model doesn’t really take into account how quickly the shift from agricultural land use to residential and industrial land use is happening in the county, he said. Homes and industries use less water than agriculture does. The state and county needs to find a way to shift grandfathered water uses from farmland that is slated to be retired to new residential and industrial developments.
Jake Lenderking, a co-vice chair of the task force and the director of water resources at Global Water, agreed. He said the new groundwater model is much more sophisticated than any of the previous groundwater models for the Pinal AMA but the new model makes some assumptions that may not be correct.
The new model doesn’t accurately calculate the amount of water that will be recharged into the aquifer or the use of long-term water storage credits or effluent, he said. The model caps the amount of water recharged into the aquifer through long-term storage credits in the Central Arizona Groundwater Replenishment District to 1,500 acre-feet per year for the next 100 years but that amount may change, Lenderking said.
The model also can’t accurately determine how much effluent is being used, he said. This is partly because there aren’t many combined water/wastewater companies like Global Water in the Pinal AMA, like there are in metropolitan AMAs like the Phoenix AMA.
Having a company that provides both water and wastewater services, as Global does in Maricopa, makes it easier to track how much water is pumped, used, treated as wastewater and returned to the aquifer as effluent, he said. When those services are split between two entities, like in the city of Casa Grande, where Arizona Water Company provides water service and the city provides wastewater service, it is harder to track.
Another problem with the model is how it calculated the shortfall in water supplies at the end of 100 years, Lenderking said. The model assumes that when a well runs dry, that is the end of the water supply for that well.
It doesn’t take into account how deep that well was drilled, he said. A well owner could drill a new well or deepen the existing well.
The model also makes an incorrect assumption about the amount of groundwater that agriculture is currently using and will use in the future, Miller said. Agriculture isn’t using its full allotment of water now. Farms have become more efficient with their water use and the number of farms will decrease as more farmland is retired and turned into developments.
All three task force members said they don’t fault ADWR for the assumptions in the model.
“They’re working within the system they have,” Garfield said. “It’s the best model available right now.”
But the task force will need the best data possible to determine possible solutions to the county’s groundwater problems, he said.
He likened the situation to balancing a checkbook — the task force needs to know how much water is coming into and going out of the system, Garfield said. The task force needs that kind of data to determine the task force’s priorities and to come up with possible solutions.
One of those solutions may be purchasing water from someplace else, Miller said.
“We will need another source of water in the future and it will cost us,” he said.
Garfield anticipated that it would take about a year for the task force to sit down with all of the various stakeholders, water companies, developers, the agriculture sector and the Indian communities and come up with a list of possible long-term legislative or regulation-based solutions for the Legislature.
At the same time, the task force is hoping to come up with some short-term solutions during that year that could be implemented sooner, he said.
Garfield said the task force’s meetings will be open to the public, but most of the heavy work will probably be done in the workgroups that will be composed of the different water users.
“We are going to get things done, real things done,” Lenderking said. “We will come out of this with a clear path for development.”