Given the tortuous existential journey Aurora’s water molecules endure through the Prairie Waters project, “recycling” seems dismissive.
“Reincarnation” feels more appropriate.
After Aurora users brush their teeth or finish the dishes, waste travels miles to Metro Water Recovery in north Denver for treatment. Cleaned up, it flows back into the South Platte River, and meanders 20 miles northeast past Brighton.
There, Aurora Water has built an elaborate well complex deep under the riverbed. The wells soak up an amount of seeping river water that Aurora has the right to reuse. Some of the seepage is pumped over a nearby gravel bed and drains again for more cleaning, is piped 34 miles back uphill to the city’s treatment plant and then blended with pristine mountain snowmelt, before heading out to pour again from water taps in homes.
The federal government is heartily dendorsing this MacGyver method of conserving water, bringing a $5 million promise to Aurora last week that will allow the water agency to double the capacity of Prairie Waters and expand the recycling project to a large portion of local needs.
Innovation like Prairie Waters is “a project that should be happening in every community right now,” said Assistant Secretary of the Interior Tanya Trujillo, who toured Prairie Waters on Jan. 13 and announced the $5 million federal contribution from the Bipartisan Infrastructure Law.
Trujillo noted the law includes more than $8 billion for Western environment and energy projects, and the subsequent Inflation Reduction Act includes $4 billion more for Western water projects amid a 23-year drought.
With federal officials demanding answers from the seven Colorado River Basin states by Feb. 1 on how they will sharply cut water use to save Lake Powell and Lake Mead, the Aurora project demonstrates how urban areas are trying to do their conservation share, Trujillo said. Agriculture uses about 80% of the water in Colorado, and faces steep cuts, but rural leaders frequently call on city water users to contribute savings.
Listen to reporter Michael Booth talk about Aurora’s plan on City Cast Denver. >> LISTEN
“The more we can do in each of those sectors to improve their efficiency and expand the ability to use every drop wisely, helps decrease the tension” among users, Trujillo said.
The $13 million expansion of Prairie Waters will double the current capacity, bringing 5,000 to 10,000 more acre-feet of clean water into the Aurora system each year. When completed, almost a third of the 55,000 to 60,000 acre feet used by Aurora each year could come from the riverbed drains. An acre-foot of water supplies two to three households for a year.
The rest of Aurora’s water comes from the South Platte River Basin, the Arkansas River system or diversions across the Continental Divide from Colorado River tributaries.
Under Colorado water law, cities have to allow water that is not used up completely to flow back into streams to satisfy downstream water users’ rights. The exception is water transferred from a Western Slope watershed, like the Colorado River Basin, to the Front Range. All of that water can be consumed completely, or “to extinction.” That exception has prompted many of the water reuse and recycling projects cropping up in Front Range metro areas that long ago bought into water projects bringing over Colorado River water.
Aurora Water’s mantra is that the water it already owns is cheaper than any other option, as prices per acre-foot soar into the thousands of dollars.
The needs met by Prairie Waters can also free up mountain runoff water rights for Aurora to support other economic interests important to the whole state, said Aurora Water Director Marshall Brown.
“The municipal sector can’t solve the water shortage on the Colorado River,” Brown said. City water use accounts for up to 8% of available water in Colorado. “But we can put together cooperative arrangements with other sectors, primarily agriculture.”
“It’s affording us the opportunity to take our time in some of those discussions looking for innovative solutions,” Brown said. Aurora expects to begin construction on the Prairie Waters expansion in 2024.
The part of the system near Fort Lupton will add another well with radial inlets extending under the riverbed gravel. Letting South Platte River water flow first through hundreds of feet of sand and gravel does much of the cleanup naturally.
Once pumped to the surface, it’s poured out over more sand and gravel for further cleaning. That water can then be pumped south to Binney Water Purification facility near Aurora Reservoir, or used to augment local pools of water that Aurora controls, depending on seasonal needs of other river users.
Aurora Water also leases water to other cities like Castle Rock and Parker, Brown said. In a flush year for mountain runoff, the growing supply from Prairie Waters can free up more supply for those leases, he said.
Colorado Agriculture Commissioner Kate Greenberg, also on the Prairie Waters tour with federal officials, said Aurora’s reuse project is one that gives state leaders hope that the zero-sum water competition doesn’t always end in farmers and ranchers losing productive land.
Maybe, Greenberg said, “It doesn’t have to be a buy-and-dry future.”