27th Avenue Stormwater Project
There is an urgent need to improve the stormwater system along 27th Avenue to prevent annual flooding. This will be a four year project, beginning July 2015 with a segment of 27th Avenue from 16th Street to 17th Street Road. Construction will be complete before the end of the 2015, after which design will begin for the next phase. Phases II through IV will carry the improvements north to the Poudre River over the next four years.
Construction Update July 22, 2016
The second half of our construction project near 28th Avenue and 17th Street is underway. We’re placing slightly smaller box culvert pipes than last fall, but they still weigh about 40,000 pounds! In the interest of safely, we’ve closed 28th Ave until about August 10. Our crews are working as fast as they can to get that road back open. In the meantime, please be safe and follow all detour signs. They’ve already started placing these boxes in 17th Street Road. Then they’ll be placing inlets in 17th Street, 17th Street Road and finally 16th Street.
Why do we need this project?
This picture shows the high water mark of stormwater on a patio door after approximately three inches of rain fell on August 6, 2008. This home on 28th Avenue is among several in the basin that experience damage during larger storm events. The 28th Avenue Drainage Basin is about four square miles running north to the Poudre River and situated west of downtown. Water at the house and other locations was measured at 18” deep. Based on historical data, there is about a 10-50% chance that the storm from 2008 could occur in any given year.
How will this project help?
Currently, the 28th Avenue Drainage Basin does not have enough storage space for larger rain events and the pipes are generally undersized. The water wants to find an easy path, which sometimes ends up being into a basement. In other areas of town, where there is vacant land, a pond could be built to provide storage, or detention, to reduce the flooding. Here there is not enough land available so concrete boxes under the streets will be used as a path for the water and also for storage. These boxes are much larger and will carry much more water than the existing pipes in the area.
What Work is Being Done?
Phase I will begin by relocating some of the existing utilities such as water and sewer lines to make room for the concrete boxes. The boxes and all of their associated parts will then be installed. Some of these parts will include new inlets so that more water will reach the boxes and less will be standing in the streets. Lastly, the streets will be restored and new asphalt placed to create a smooth driving surface. The sketch shows a cross-section of what will be underneath the street when it’s all finished.
When and Where?
Construction in the Phase I area will begin in August of 2015 and will be partially complete by December 1st. The remainder will be done next spring, about the same time as construction of Phase II is scheduled to start. Phase II will include work in the Woodbriar Park/19th Street Area. Phase III will continue the project northward along 27th and 26th Avenues, the timeline for this is approximately 2-3 years from now. After that, Phase IV will see improvements in the #3 Ditch and northerly channel all the way to the Poudre River.
27th Avenue Phasing | PDF 1MB