Water tap

The Town of Marana has big ideas for development, and water is the key to making that happen. At last Tuesday’s study session, town staff updated the council on the progress of various water projects, all of which would streamline Marana’s water systems and open up vacant land for future construction.

One of Marana’s largest projects was unanticipated. After test results in January 2018 showed elevated levels of perfluorinated compounds and 1,4-dioxane in the Picture Rocks and Airline/Lambert water systems, town staff had to work quickly to identify a solution.

There is currently no federal regulation on the amount of these chemicals in drinking water, but the EPA recommends the levels should not exceed 70 parts per trillion. Marana received sample results in January ranging from 68 to 101 parts per trillion. 

There are five other water systems in the town that are unaffected.

While a lawsuit against the companies they deem responsible is currently pending, Marana secured a $15 million loan from the federal Water Infrastructure Financing Authority to build two water treatment systems. In January the town hired Carollo Engineers to design the purification systems, and they are currently running tests to see which kinds of filters will work best to separate those unwanted compounds from the water supply.

John Kmiec, Marana’s water director, told council the Picture Rocks/Continental Reserve treatment facility should cost around $5.7 million, the one at Airline/Lambert should cost around $4.3 million, and they are anticipating a $2 to $5 million increase in those numbers to account for price escalations, future capacity sizing, contingency and other factors, bringing the total cost between $12 and $15 million.

Just two weeks ago, town staff received statements of qualifications from construction companies, so they should be choosing a construction manager in the near future.

According to the town’s timeline for this project, they expect to complete the design of the project and finish negotiating the guaranteed maximum prices with a contractor in the next few months. They anticipate breaking ground on the project in August. The construction should take place over a year and be finished by the summer of 2020.

“We’ve been talking with our engineers right now to come up with a maximum design criteria, so not only meeting the current customer demand but having those additional supplies go through these two systems,” Kmiec said during the study session. “We don’t want to build them too big, but we want to build them big enough that we can handle not only the affected areas but actually be able to produce water for other systems.”

While purifying the water is highest priority right now, this problem highlights the issue with Marana’s seven isolated water systems. Kmiec said that since the town is so large geographically, development that occurred over the last 50 years has been done in isolated neighborhoods with their own water systems.

“Now that the town is starting to infill, the benefits of a connected water system are starting to be realized,” he said. “Initially they developed as small rural water agencies, and they represent those historic neighborhoods throughout Marana.”

If all the water systems were connected and interdependent, town officials agree that they could have chosen the much simpler solution of mixing water sources until the chemicals levels dipped down to a safe amount.

“We never had that option, which is why we went ahead with the more expensive solution which is treatment at our well sites,” said Town Manager Jamsheed Mehta. “But through interconnects like the City of Tucson did, that would have been at least an option that we didn’t have at that time.”

The town has two projects in sight that would be a starting point for connecting those isolated systems. One, the Twin Peaks-Continental Reserve Interconnect project, involves building a pipeline from the water treatment facilities going in at Continental Reserve to join with the Hartman Vista systems to the north.

By doing this, Kmiec said the town could have high quality water moving to the rapidly developing Twin Peaks area or back the other way to Picture Rocks if needed. This increases redundancies in the water systems, which is ideal for town staff to ensure that water service goes uninterrupted.

The other project intends to bring water to the east side of Interstate-10 and Tangerine Road. Town officials are looking to build another pipeline that will move water from the northwest side under the freeway to connect to the tank and pipeline in Tangerine Business Park. This would provide gravity pressure to those areas in the commercial corridor, Kmiec said.

Marana Water officials want to take advantage of gravity pressure areas, which is where water is stored at a higher elevation than where it is being delivered to. Moving water uphill requires more energy, and therefore more money.

If both projects are completed, this would make five out of the seven water systems connected.

“All these puzzle pieces are out there, they are starting to come together and with growth of the town we’re seeing these things as more and more realistic,” Kmiec told the council.

 

Putting “wet water” to use

When water officials in Arizona talk about “wet water” it’s a reference to recovering water from where it has been stored in an aquifer. The Town of Marana is entering an intergovernmental agreement with the Town of Oro Valley and the Metro Water District to bring stored CAP water in the Santa Cruz and Avra Valley recharge facilities to the higher density areas that have been utilizing groundwater pumping.

Kmiec told council that over the last 20 years, water in excess of 600,000 acre-feet has been banked within the town.

“What we’re embarking on with the Town of Oro Valley and Metro Water is to finally put some of that wet water to use, to meet our needs of our respected areas,” he said.

This project has a maximum capacity of 10,400 acre-feet of withdrawal. Within the agreement, Marana will have ownership of 2,400 acre-feet per year (23 percent) and Oro Valley and Metro Water will each own 4,000 acre-feet per year (38.5 percent each).

Kmiec said the IGA is flexible; the three partners will have the ability to share and exchange their allocated amounts as long as they don’t overreach capacity. This is also a cost-saving move by the town because the two wells near the airport are “grossly underutilized,” according to Kmiec. This project will allow the town to stop pumping groundwater in eastern Marana, saving money and precious resources. 

“Trying to come up with enough water in the Twin Peaks corridor is going to be a challenge,” Kmiec said. “And being able to move the wet water from an area of high storage and greater storage to the Twin Peaks corridor will provide greater protection for those areas.”

Marana will have to pay for some infrastructure improvements and add a booster to make this happen, but the responsibility of any future wells or pipeline acquisitions will fall on Metro Water and Oro Valley.

In addition, Kmiec said if water levels in Lake Mead drop too low, municipalities like Marana could be affected by shortages. With this agreement, the three partners could access water from the Arizona Water Bank that is stored in the recharge facilities to use for recovery. Kmiec said there would be enough water from that source to fulfill their contracts.

Although having two partners requires more infrastructure to be built for delivery, Mehta said this is a project that Marana would have had to do anyway and so the cost-sharing model works in this case. He said the town wasn’t initially looking for this solution, but developers in the eastern parts of Marana are currently under an agreement with the town to drill their own wells and pump groundwater.

“It would be a very inefficient way of trying to get water to an area where the water levels have already gone down quite a bit over the decades,” Mehta said. “So this helps the future developments in Marana by having water that’s coming from an assured source instead of relying on the wells that they would have to put in.”

 

Studying floods

Keith Brann, Marana’s town engineer, presented the first phase of the town’s northwest drainage study at the study session, which helps depict a better understanding of how water moves through Marana’s landscape. This will help inform town officials about how rainwater movement would impact any future buildings built within the town.

With four inches of rain over a 24 hour period, the drainage study found that 12 hours after a storm, water starts to move through the town via culverts under I-10, interchanges, canal infrastructure and begins flooding in areas like Barnett, Grier and other northern sections of town.

“We’ve seen things like in the past,” Brann said. “Even a couple years ago we had a moderate storm on the Tortolita fan and as the water moved through town from the cap overshoots, we had a couple hours worth of rain but almost an entire day of flood fight. So having this information is definitely going to help us deal with infrastructure.”

The next phase of the project will build on this knowledge and identify solutions. The options, while still under further review, have been identified by town staff as channels placed along different roads that could divert some of the water away from both open space and commercial or residential areas in northern and western Marana.

Mehta said if the town can figure out a way to relieve flooding after monsoons, it would open up a lot of land for future development projects and prevent clean-up costs after even a storm.

“Right now the amount of work we have to go through to clean up after every monsoon season, this part of north Marana especially is where the majority of the growth and development in Marana is going to happen for the next several decades, and monsoon rains and regional waters are one of the reasons why it’s going to be held back,” he said. “So not only is it a cost that we’re incurring each year but it’s also the fact that it’s holding back development.”

At the study session Mehta informed council that town staff should be coming up with estimated costs for all of these projects within the next two to four weeks. This will give council an idea of which funding sources they should to look toward, since these projects are not included in the town’s five-year capital improvement plan.

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