Flood overtops Mancos wastewater lagoons; avoid the river, town says
The Town of Mancos says historic floodwater from the Mancos River overflowed its treatment lagoons late Sunday night, that the earthen berms held, and that people should keep out of the river below Cottonwood Park. Drinking water is safe, it says, but water use must be cut for about two weeks.
Floodwater from the Mancos River overtopped the Town of Mancos’s wastewater treatment lagoons late on Sunday night, the town said in a notice published on Monday, and it is asking people to stay out of the river downstream of Cottonwood Park until further notice.
Graphic: Cortez Current. Source: Town of Mancos public notices; National Weather Service Grand Junction
The town’s emergency update says “historic floodwaters from the Mancos River unfortunately overtopped our wastewater treatment lagoons, causing water to overflow into and out of the ponds.” It adds that the structures themselves did not fail: “Our earthen walls and berms remain structurally sound and did not break; the sheer volume of the river simply exceeded the height of the barriers despite our team’s efforts at Cottonwood Park.”
The town says its crews stayed on the scene and that it has notified downstream partners — naming the Colorado Department of Public Health and Environment, the Ute Tribe and federal oversight agencies — “to ensure a coordinated response,” and that it is working with environmental experts to track downstream impacts.
Its instruction to the public is one line: “Please avoid contact with the Mancos River water downstream of Cottonwood Park until further notice.”
The notice does not say how much water left the ponds, how far downstream it traveled, or how long the advice to stay out of the river is expected to last. It closes by thanking town staff, the Mancos Fire District and heavy equipment operators from Ground Breaking LLC.
Drinking water is safe, the town says — but use less of it
A second notice, published the same day, addresses the tap. The town says there are “currently no known drinking water quality concerns affecting the Town’s treated water supply” and that “the water remains safe to drink.” The wastewater notice makes the same point, saying the overflow “impacts the wastewater system, not the town’s treated drinking water infrastructure, which is upstream.”
What the flood has affected is how much water the town can treat. Because of what it calls historic flooding and increased sediment levels, the town says it is “experiencing concerns regarding water availability” and that “water conservation is required at this time.” It asks everyone to limit nonessential use, and estimates that the elevated sediment “may take approximately two weeks to dissipate.”
A separate, shorter notice puts the same request more plainly: because of the flooding and high water levels, “it is imperative that Town of Mancos residents conserve water to help ensure adequate water treatment.”
The drinking-water notice adds one item for people not on town water. Residents in the 81328 ZIP code who rely on private wells or cisterns are encouraged to contact the town for help getting water testing kits to check for possible contamination. The notice names “MMO or Mancos Town Hall” as the places to ask and does not spell out the acronym; Mancos Town Hall is at 117 N. Main St.
Cottonwood Park is shut, and could be for months
Cottonwood Park, where the lagoons sit, “remains CLOSED to public use until further notice due to damage caused by the recent historic flooding,” the town’s parks notice says. The capital letters are the town’s. It says damage assessments, trail repairs and restoration “will be ongoing and may take several months to complete.”
Boyle Park “continues to experience flowing water,” the same notice says, and it asks people to use caution at parks and open spaces generally: “If it’s flowing, don’t go!”
A sixth notice covers the town’s streets and closes the South Spruce Street bridge.
The river
The weather service’s flood warning for the Mancos River near Mancos was re-issued at 6:09 p.m. on Monday and now runs until 10:15 p.m. on Tuesday. It describes moderate flooding, well above the minor flooding the first bulletin forecast on Sunday morning.
The gauge read 8.1 feet at 5 p.m. on Monday, and the highest reading in the 24 hours to that point was 8.3 feet. Bankfull is 5 feet and flood stage is 6 feet. Under impacts the bulletin says that at 8 feet, “residential flooding in Mancos is likely.” It expects the river to fall below flood stage late on Tuesday morning and to keep dropping to 4.4 feet by late Saturday morning.
The Town of Mancos also said on Monday that all evacuation orders have been lifted, while asking people to stay cautious and to keep clear of flooded roads.
Where the notices are
All six of the town’s Monday notices are on the Town of Mancos website. The weather service’s active products for the county are on its alerts page, and any active watch or warning also shows by itself on the alert bar at the top of every page on this site.
For an emergency, call 911.