City of Glenwood not concerned about long-term effects to No Name water supply from fire
Glenwood Springs’ public works director said the city is well-equipped to handle the Grizzly Creek Fire’s potential long-term effects on the city’s primary water supply.
Public Works Director Matt Langhorst said that this time of year about half of the No Name water supply of 5 million gallons a day comes over from Grizzly Creek through a diversion about four miles up Grizzly Creek.
According to the most recent fire mapping, the fire has not yet started burning upstream of the Grizzly intake, but as of late Wednesday it has burned down to No Name Creek.
The city on Tuesday shut off the No Name supply to prevent from having fire retardant enter the city’s water. It is now pulling water from the Roaring Fork River.
When fires burn in a watershed, it is common for there to be an increase in sediment in the stream, as burned vegetation no longer holds soil and material flows downhill.
Langhorst said the water system can handle sediment.
“Sediment’s definitely a concern. If all the vegetation on the hillsides around the creek burns off during a rainstorm more sediment travels down the hillside and enters the creek,” he said.
“We can handle quite a load of sediments, but yes, it is definitely a concern. It clogs things up, makes maintenance a little more difficult, makes some of the chemicals we have to purchase to pull the sediment out of the water a little more expensive, but it’s something we can definitely handle.”
Langhorst also sees little risk from increased runoff, another common occurrence following a fire.
“That’s not a problem for us unless it overtakes the intake structure we have. It’s fairly high above the creek, and we divert to it. There’s quite a bit of volume that can pass by without damaging it. We’re pretty well off,” he said.
He said the water department will have to do water tests before the system is turned back on again to see what’s in the water, as burned soils can release materials that didn’t come down before the fire.
He also said he’s been wondering what ash might do to the water system.
“I haven’t dealt with an ash incident in a water system. It’s a question I have in my head, also,” he said.
Langhorst said the switch to the Roaring Fork supply was to avoid getting fire retardant into the water system.
“We didn’t want [retardant] going directly into our intake and through the tunnel system. We have 15,000 feet of conveyance system. I didn’t want it entering that because I wasn’t sure what it would do to it,” he said.
The use of Roaring Fork water is based on the city’s 500 acre-feet of water rights from Ruedi Reservoir. Langhorst said that the city can rely on that water for “quite a duration.”
He did reiterate what the city said in its Tuesday press release: Residents are asked to refrain from watering lawns.
Langhorst explained that the city has two pumps pulling 2.5 million gallons of water from the Roaring Fork, but he would prefer to use one a time.
“If that pump failed for some reason we’d have another pump to turn on. … We’ve built safety and redundancy into the whole system, and we try to conserve water,” he said.
Conserving water increases the time the city can use the Ruedi allotment.
“We’d like to alternate the pumps, keep it to 2.5 million gallons a day. The less water we pull from Ruedi the longer we can pull water. With one pump running we could pull for 55 days or something like that,” he said.
There is likely to be some extra expense to the city to using Roaring Fork water.
“There can be [extra costs] depending on how clear the water is. … If we have more particles in the water we may have to use a little bit more chemicals. …That’s all we’re looking at at this moment for potential additional costs, but the Roaring Fork water now is pretty clear,” Langhorst said.
The Roaring Fork water is not gravity fed like the No name supply is, necessitating pumping the water up to the treatment plant.
“The pumps would obviously add some cost,” Langhorst said.
Langhorst said he’ll be looking more closely at the No Name and Grizzly fire situation in the coming days.
“Depending on how far it goes up the draw will change answers dramatically,” he said.
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