From The Pueblo Chieftain (Chris Woodka):
Under its 1041 agreement with Pueblo County commissioners for the Southern Delivery System, Colorado Springs is obligated to dredge Fountain Creek through Pueblo to maintain the effectiveness of flood-control levees. Commissioners are looking at the purchase of an out-of-service railroad bridge, combined with sediment collection and removal systems, as an alternative to dredging…
Earlier this year, Pueblo’s stormwater consultant, Dennis Maroney, told commissioners that the out-of-service Union Pacific railroad bridge sits too low in the Fountain Creek channel and could act as a dam during high flood flows. Removing it, then improving the approach to the bridge, would be a more effective solution than continually dredging the channel, he said.
Commissioners have not decided how to proceed or how the money would be spent.
Meanwhile the Bureau of Reclamation is assuring residents below Pueblo Dam that the structure is safe despite recent warnings from a group — Consumer Advocates, Inc. Here’s a report from Chris Woodka writing for The Pueblo Chieftain. From the article:
A group called Consumer Advocate Inc., run by Michael Satterfield, raised questions of the dam’s safety based on a 1977 report by W.A. Wahler. The report found safety flaws in the dam just two years after it was completed. In an open letter in the Colorado Springs Gazette earlier this month, Satterfield wrote: “It has gone on to become one of the most safety modified dams in the country. Several of the problems cannot be fixed by additional engineering. Wahler’s report states that the soil under the dam is unstable and undermines the stability of the dam itself.” The same report has been cited by Colorado Springs Councilman Tom Gallagher in his claims that Pueblo Dam cannot be operated for its designated purposes, much less for the proposed Southern Delivery System, which Gallagher opposes.
Reclamation has updated its publication, “Safe Then; Safe Now, a Summary of Pueblo Dam’s history.” It addresses the Wahler report, saying that two terms in the report have been “widely misused and misunderstood.” The Wahler report calls Pueblo Dam a “high hazard dam” and talks about “seepage.” Reclamation responded:
– “ ‘High hazard dam’ is a classification term used in reference to dams located above populated areas, such as Pueblo, and does not indicate anything about a dam’s overall performance.
– “ ‘Seepage’ describes the water that moves through all dams. Pueblo Dam has features to control and collect the seepage in a safe manner and equipment that monitors seepage through the structure.”
In a 2000 updated study on the safety of dams, Reclamation concluded that 17,000 Puebloans could be at risk if Pueblo Dam were to fail. The scenario would involve a “probable maximum flood” that would be many times greater than the largest recorded flood on the Arkansas River in 1921. Since 1977, several improvements have been made on the dam, Reclamation said. In 1981, a stability berm was added to the base of the northern earthen embankment. In 1998, drain pipes were installed downstream of the north embankment to collect and monitor seepage that occurs at high water elevations. In 1998-99, Reclamation added a massive concrete “door stop” in the stilling basin and tied the foundation of Pueblo Dam into underlying rock with long metal rock bolts to prevent possible slippage of the concrete buttresses in the middle of the dam. The Reclamation report also notes that the full capacity of the dam, almost 350,000 acre-feet, is not used in order to provide flood protection for Pueblo.
More Southern Delivery System coverage here and here.