From The Pueblo Chieftain (Chris Woodka):
There would be little impact on water rights if flood control structures on Fountain Creek were designed to allow 10,000 cubic feet per second of water to pass through Pueblo.
That’s the conclusion of a draft report by engineer Duane Helton commissioned by the Fountain Creek Watershed Flood Control and Greenway District, released this week.
The district is looking at the issue as part of its investigation into the feasibility of building either a large dam or series of detention ponds on Fountain Creek. A U.S. Geological Survey study shows those are the most effective way to stop high flows from inflicting more damage on the waterway through Pueblo.
A study for Pueblo County by Wright Water Engineering indicates those flows have been worsened by development in Colorado Springs for the past 35 years — from both more impervious surfaces and the introduction of imported water. About 363,000 tons of additional sediment each year are deposited between Colorado Springs and Pueblo.
Helton’s study, which is now under review by interested parties, indicates that water rights during extremely large floods would not be affected because water would be stored in John Martin Reservoir. That same situation occurred this year during six weeks of moderate, but prolonged flows on Fountain Creek.
“Although the owners of the ditches and reservoirs on the Arkansas River are appropriately concerned about the effects of the Fountain Creek flood remediation project on their diversions under the priority system, a conclusion from this analysis is that the operation of the Fountain Creek Flood Remediation Project will not have significant effects on the diversions into the ditches and reservoirs on the Arkansas River in at least some of the years,” Helton’s report states.
Helton analyzed data since 1921, with about 75 years of flow records for Fountain Creek. The records were unavailable for some years. There were 18 years where the peak flow exceeded 10,000 cfs.
He modeled floods in 1999 and 2011, concluding that about 5,291 acre-feet would have been impounded during the 1999 flood and 368 acre-feet in the 2011 event if flood control was managed for everything above 10,000 cfs. In the 1999 flood, there would have been little if any impact on downstream rights, since John Martin storage was active.
The report also concluded that a method could be developed to ensure downstream water users would get water they otherwise would have been entitled to receive.