Behind the scenes: Carbondale’s water system

At first glance, it’s an unassuming boulder filled draw on the flank of Sopris. The few obvious trickles of water are nowhere near enough to supply a town, but there’s a rushing sound just under the surface.  Open a trapdoor in the concrete catchment, and you’ll find a steady flow of 400 gallons per minute even in drought, which can more than double during runoff.

South Nettle Creek has had a collection system since the 1800s and a documented water right dating back to 1922. In those days, a wooden pipe traversed the nine miles to Carbondale — an unusually long distance, but almost certainly worth it.

“If I was living back in that day and knew anything about water, I’d have chosen Nettle Creek over anything else myself,” Public Works Director Kevin Schorzman said. “You see the mountain covered with snow most of the year and you know it’s a reliable source.”

Treatment

“So many people take it for granted,” said Utilities Director Mark O’Meara. “Everyone thinks water should be free, but if you want it processed, cleaned and delivered, that’s where the cost is.”

The newly metal sided facility further down the winding dirt road has an air of isolation despite being 20 minutes from town. It’s cold inside, even in summer, and crews have encountered bears and mountain lions in the narrow ravine.

“When you’re up here all alone, it’s almost spooky,” O’Meara admitted.

Though crews are in and out every day, the system is fairly autonomous. A significant drop in elevation provides plenty of pressure, eliminating the need for pumps in most cases. Indeed, the town is taking proposals to study the feasibility of a hydroelectric station on the run.

Flow, quality and turbidity (cloudiness) are monitored remotely, and if something seems off, everything can be shut down until crews arrive. You won’t notice that kind of hiccup down in town — storage and the sheer amount of water in the pipes more than compensate. Indeed, it takes about a day for it to reach some taps.

It’s difficult to filter and treat for everything, but luckily most potential contaminants have one thing in common: a negative charge. The water is treated with a positively charged liquid polymer, which binds dirt and the like as the mixture is screened through a layer of inert plastic beads — which folks up the Crystal might recognize from the time some escaped during a backwash earlier this year. Like the anthracite coal, sand and garnet sand that captures the polymer and further purify the water, it’s inert stuff which, with regular cleaning, has lasted since the ’90s. Again, the process mimics how natural ground water seeps through porous rock, leaving behind impurities along the way.

Carbondale doesn’t fluoridate, but does add chlorine, with just about enough time to kill anything dangerous before it leaves the plant and plenty by the time it reaches most homes.  A handful of subdivisions along the way also benefit from the municipal system, as does Satank despite being outside city limits. Once again, it’s all gravity powered, with pressure release valves spaced along the way.

The bulk of it goes to a large concrete tank on White Hill, which provides storage, pressure regulation and acts as a sort of gigantic gauge. A smaller tank serves River Valley Ranch.

Other sources

If you’ve ever noticed a slightly different flavor in your tap water at the change of seasons, or seen spotting on your dishes, it’s probably because the Town is supplementing the Nettle Creek supply with wells. The gravity fed system’s efficiency makes it the default, but when demand drops the level in the White Hill tank under 17 feet, things kick on at the big photovoltaic covered building at the foot of the hill in Delaney Nature Park, which draws from wells on the Roaring Fork River. A second system on the banks of the Crystal near the High School has been undergoing improvements and, although O’Meara actually prefers the taste of the water there, is relegated to third place.

Each provide comparable capacity to the Nettle Creek plant, though they rarely reach it. They also use completely different filtering technology, a product of changing requirements over the years. It’s a bit of a double edged sword, with a fair amount of redundancy but a steep learning curve for new crew members.

“The technology is fantastic, but having operators who really know what it does is essential,” Schorzman said.

That’s not even counting the ditches, which provide untreated irrigation water to residents and most parks and open space. Those pour right back in the river, while stormwater is collected in dry wells and treated water comes out the tap and eventually goes down the drain.

Back to nature

In O’Meara’s office, where you can see the bimodal bumps in waste as the town wakes up in the morning and gets home in the evening, or in the main testing lab at the Utilities Department building, the odor isn’t too noticeable. You’ll get a good whiff as you walk toward where the sewage is actually  filtered — here’s where you might look for that lost diamond ring — and ground up by what amounts to a gigantic garbage disposal. By the time it’s being broken down by microbes in a big serpentine tank, it smells more like dirt.

The liquid parts are clarified while the solid stuff is sent back through the process, reducing the waste that ends up trucked to the landfill and keeping the whole thing alive like a sourdough starter. By the time the water reaches an outdoor serpentine basin, its turbidity isn’t much higher that the river it’s being returned to. The whole process takes about a month, and while O’Meara has plenty of anatomical metaphors to explain it, there’s a much nicer natural comparison. (Diazepam)

“A river would do the same thing, we’re just doing it in a compact area,” he said.

Added  Schorzman,“The closer you can come to replicating natural process, the better your results will be.”