Over the years, the concrete drainage channel that runs through PenrosePark continued to deteriorate. The channel was in such bad shape in 2006 that the City’s General Fund allocated some emergency capital improvement project funding to its restoration. This was prior to the creation of the Stormwater Enterprise. With Stormwater Enterprise staff available to design and implement the improvements in 2008, the project was completed and features two unique aspects.
Rather than replacing the damaged concrete with new concrete, the design included replacing 1250 feet of the channel with a natural bottom, starting from Oro Blanco Dr. and going downstream. This has several advantages. Water quality is vastly improved when runoff streams through a natural wetlands area compared to a concrete channel. The wetlands serve as a natural filter to remove pollutants from the runoff. The vegetation also serves to slow down the velocity of water moving in the channel. Those viewing the project this year will see a straw bottom in the channel that will produce lush vegetation over a one to two year growing cycle. The aesthetics of a natural channel are much more appealing than a concrete channel.
The Stormwater Enterprise will look for other opportunities to replace concrete channels with a natural bottom when possible, but certain conditions have to exist to make it possible. The main consideration is dependant on acceptable hydraulic requirements and adequate transition zones where the natural channel meets the concrete channel, otherwise, the natural portion could be subject to damage during times of high runoff.
In addition to the unique aspects of the channel replacement, this project featured extensive safety improvements. Because of the channel’s location near PenroseElementary school and the park, 1350 feet of fencing was added as a safety feature.
Children who attend Penrose Elementary or use PenrosePark were often walking in the channel, creating safety concerns in the event of a flash flood. The channel also had significant ice build-up in the winter, creating a dangerous situation for children walking in it. The fencing will guide pedestrians to use the bridge crossing instead of walking through the channel.
General Fund:$495,000 (came in almost $22,000 under budget)
(General Fund money was allocated to this project prior to the creation of the Stormwater Enterprise)