Camp Creek flood-fix options: 2 with ditch, 1 underground
The information was presented in a Feb. 25 public meeting at Coronado High, the third since October in the study effort. Feedback from the more than 100 meeting attendees, combined with further engineering study, will lead the city to recommend a “preferred alternative” at a meeting to be scheduled in April, according to Susan Watkins of Kezziah-Watkins, the study facilitation group.
Variables in the alternatives include three possible detention ponds along Camp Creek between Gateway Road and the northern limits of the Garden of the Gods. One of these would raise Gateway Road itself (anywhere from 5 to 14 feet) to allow a pond behind it. The extent to which ponds are used to hold back water in a flood would affect how wide and deep the ditch would need to be or the size of an underground culvert.
All three alternatives would remove the 224 residences and 13 commercial lots from Pleasant Valley south from the official 100-year flood plain, according to project handouts.
“All three will provide greater safety from a flood,” Bob McGregor of AMEC Engineering, a subconsultant on the study, told the meeting attendees. “They are even in that respect.”
They are also roughly even in costs. Each of the alternatives has what the study terms a “ballpark cost estimate” between $31 million and $37 million.
No funding has been earmarked yet for any work. Asked about this point during a question/answer session at the meeting, Mike Chaves of City Engineering responded, “We don't have $30 million sitting in the bank. We're looking for grants, and there will be city money. We may phase it over time. We hope by next year to have the money to do some of it.”
No matter which alternative is chosen, other changes in the mix are:
- rerouting Camp Creek for a few hundred feet north of Pleasant Valley (from the west to the east side of the chapel in Rock Ledge Ranch) to eliminate a sharp bend.
- Extending the current undergrounding of Camp Creek another block north, to Platte Avenue, because the slope there “creates design problems,” according to Bob McGregor of AMEC Engineering, a subconsultant on the study.
- “Drop structures” (rocks placed at intervals to reduce erosion as the creek flows downhill) will be installed north of Pleasant Valley.
- Sediment control will occur at the north end of Garden of the Gods, where Camp Creek emerges from the Navigators property (Glen Eyrie). Work on this project has already begun. See story.
Here are capsule summaries on each of the alternatives:
Upstream work would involve… raising Gateway Road at least 5 feet near its Camp Creek crossing and widening its bridge for safety reasons.
The wider ditch would also require moving the street closer to the sidewalks, reducing the size of the parkway by nearly six feet. “You'd lose a little parking,” McGregor said.
Upstream work would involve… detention options of building either one large pond behind a 28- foot-high earthen dam in the north part of the Garden that would extend across the valley, or two medium-sized ponds (one behind a 19-foot-high earthen dam, also in the north part of the Garden, and a second created by raising Gateway Road up to 14 feet where it crosses Camp Creek).
Upstream work would involve… detention options of either raising Gateway Road for a pond behind it as in Alternative 2, or building a 19-foot-high earthen dam/pond, also as in Alternative 2.
One audience question was about maintenance. Chaves said all three would require such attention. But regarding a concern about silt building up in the box culvert, Vance Fossinger of Wilson & Co., the study's consulting firm, said he does not believe that will happen because concrete carries water faster.
In connection with maintenance, it was announced at the meeting that repairs on the current 31st Street channel will take place before July. After the meeting, Chaves elaborated that nothing major is planned. A contractor will be hired to do "spot fixes" on places that the concrete was compromised by the water last year. "It's just a bandaid, to buy a little more time," he said.
Another meeting concern was raised by a group of local residents representing the interests and traditions of American Indians, wanting to ensure that any sacred sites along Camp Creek will not be compromised by any creek work. Matt Mayberry of City Cultural Services said he will be working with the group in researching those issues.
Also, in response to an audience question, Chaves said the study team will be researching the potential noise-level increases for Alternative 2, as a result of of 31st Street being proposed nearly six feet closer to the homes on either side.
Westside Pioneer article