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BOISE — Boise’s treated wastewater could take on a new life watering crops in northwest Boise, creating concern for some residents.

With the Treasure Valley’s mountain desert location and the looming threat of climate change, Boise Public Works officials say using cleaned wastewater for other purposes is essential to planning for the future. Being able to pump highly treated wastewater into Farmers Union Ditch Company’s irrigation canal would help the city meet new federal regulations and boost irrigation canal levels. But some canal users worry the move could expose them to harmful bacteria and chemicals.

Public Works Director Steve Burgos said the city is still exploring the option and will have to get final approval from the mayor and city council next spring before proceeding. If they get the go-ahead, the wastewater would not start being pumped into the canal until the mid-2020s. The water possibly being put into the canal would be cleaned at a higher level than the current process, making it safe for human contact, except for drinking.

Currently Boise treats all of its wastewater at two water renewal plants before releasing it into the Boise River. Under new environmental requirements set to take effect in 2022, the treated water hitting the river must meet be below a certain temperature.

Burgos said if the city pumps some of its treated wastewater into the canal instead of the river during the warmest months of the year, it would help the city meet the requirements at low cost, as well as help refill the canal during some of its lowest months of the year. The alternative is costly, and not nearly as effective as using Farmers Union to keep warm water out of the river.

“Our water is pretty warm that we get from the community, so we’re trying to take that heat load and put it somewhere else,” he said. “If we don’t do that, something we might have to do is put chillers at the end of a renewal facility. That’s bad for many many reasons. It’s not good for energy, it’s not good for costs.”

Farmers Union canal begins near Esther Simplot Park and travels through northwest Boise out to Eagle, where it irrigates fields, gardens, parks and yards. Under the agreement, Boise would pay the ditch company $50,000 annually for a 25-year agreement. Northwest Neighborhood Association President Richard Llewellyn said his semi-rural neighborhood heavily uses the canal for agriculture, but also for swimming and fishing.

The idea that treated wastewater could come through the canal in the next few years is worrisome, he said, especially because it wasn’t well-publicized.

“I personally didn’t learn about this until our neighborhood was looking into documents about the city’s budget,” Llewellyn said. “Oddly, we hadn’t heard anything about this even though we’re writing a neighborhood plan with the city and we have talked to them about using our canals for recreation.”

Boise did hold a citizen advisory group related to water reuse issues, but no one from Llewellyn’s neighborhood participated.

Llewellyn, who holds a doctorate in biochemistry, said he is worried about chemicals in the wastewater referred to as “Contaminants of Emerging Concern,” which come from pharmaceuticals and other personal care products coming through the canal. According to the Environmental Protection Agency’s website, these contaminants are being increasingly detected at low levels in surface water.

The EPA said these chemicals are known to alter the reproductive system of aquatic animals at low levels of exposure, but the effects cannot be fully studied until the animals reach adulthood, so information on these effects is still limited.

Llewellyn is concerned about that kind of water flowing through his neighborhood canal, especially in dryer months when most of the water would be sourced from the treatment plant.

“Effectively you are concentrating it when you put it into the canal,” he said. “Especially toward the end of the year this canal goes way down, so it will be substantially if not all (water from the plant), and then you’re putting it into a system that maximizes human contact.”

In response to these concerns, Boise Public Works spokesman Colin Hickman said in an email the chemicals are found throughout the community and residents are already regularly exposed to them in a variety of contexts.

“While we absolutely share the concern about CECs ... it is important to note that CECS are found nearly everywhere, in the Boise River, in irrigation ditches (including in the Farmers Union Ditch Company currently), and in many other types of water,” Hickman said. “It’s a global issue, not just an issue about one specific irrigation ditch or about reuse or about water renewal services.”

The city has not submitted its final permits to Idaho DEQ to put treated wastewater into the Farmers Union canal. But Burgos said even if they had, it does not necessarily mean approval. He said receiving a permit to complete a process is not akin to a building permit, giving approval to immediately start. Instead, a permit for something like this is a list of requirements the city has to meet, which allows officials to start planning and nailing down exactly how much the process would cost.

Neighbors also expressed concerns about a phrase in the proposed contract language between the city and Farmers Union saying the city would attempt to get permission to discharge water of less than Class A quality into the canal, but Hickman said the language is “not very clear” and the city will only put Class A quality water into Farmers Union.

In order to meet heightened demands for water renewal and to meet the impending stricter requirements on quality, Boise began a large expansion and update of its Lander Street Water Renewal Facility off of State Street. If the city decides to move forward with putting the treated water into the canal, that’s where it would originate. Hickman said the design for the plant upgrade is not assuming the Farmers Union plan will be approved.

Llewellyn said while he acknowledges the need to consider water reuse for Boise’s future, he is not sure this solution would be worth the risk.

“It’s not solving a problem,” he said, “other than the regulatory problem that is arising from the more stringent water quality standards.”

Margaret Carmel covers the city of Boise. Follow her on Twitter @mlcarmel or reach her by phone at 757-705-8066.

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