A stormwater project involving the North Douglas Creek Channel acting as a drainage channel was recently completed in Colorado Springs, Colo.
While the North Douglas Creek Channel has always existed as a natural drainage channel for stormwater beginning on the west side of Colorado Springs and leading to Monument Creek, it was altered as there was an increase in development on the west side of Colorado Springs. According to Colorado Springs Stormwater Enterprise Manager Richard Mulledy, “The channel conveys up to a 100-year rainfall event through the city to Monument Creek.”
When the Environmental Protection Agency performed an audit of the city in 2013, issues with the North Douglas Creek Channel were found. These issues were then addressed in the city’s intergovernmental agreement with Pueblo County. During the audit, it was discovered that a section of the North Douglas Creek Channel had suffered serious erosion, which was causing damage to adjacent properties, area utilities and threatening the adjacent railroad tracks and Sinton Road.
In order to fund the North Douglas Creek Channel project, the city of Colorado Springs utilized multiple funding partners. The city applied for a competitive Pre-Disaster Mitigation grant through the Federal Emergency Management Agency and was awarded the grant. This grant provided 75% of the project’s funding and required a 25% match from the Colorado Springs Stormwater Enterprise. However, this grant did not cover all the necessary expenses for the project. These additional expenses were funded by the city’s Stormwater Enterprise and Colorado Springs Utilities. The funding by Colorado Springs Utilities was focused primarily on elements of the project that involved protecting, relocating and removing utilities surrounding the project area.
Design for the project started in 2019. Project construction lasted from August 2022 to April 2023. Mulledy stated, “The completion of this project helps the city to reduce sediment washed downstream into Monument and Fountain creeks that run through the city, protects utilities threatened by the eroded creek and protects adjacent infrastructure like I-25 and railroad tracks.”
Erosion was threatening Sinton Road and I-25 at a culvert underneath the roads. “The erosion at this culvert was so severe that the sides of the culvert had fallen off and the erosion was moving toward the roads,” Mulledy explained. “There was also a six to seven vertical foot drop out of the culvert that was unsafe if someone was inside the culvert. The project also protects critical utility infrastructure and potential outages to the city caused by the creek damaging utilities. The project does not retain water like a pond, but is a channel that will continue to move water to Monument Creek. The project improves water quality by reducing the erosion in the creek that causes dirt and materials to wash downstream into Monument Creek. The constructed improvements in the creek are made to help slow down the water and reduce sediment from being washed downstream.”
These improvements included the entire channel being regraded to flatten out vertical eroded backs; multiple large, grouted boulder drop structures, similar to stair steps, being installed along the creek; the culvert under I-25 undergoing repairs; and the creek being replanted with native grasses and trees.
However, there were some challenges faced throughout the project that had to be overcome. “The project team had to work with several large companies that were adjacent property owners to gain access to the creek due to the creek’s location adjacent to I-25 and railroad tracks,” Mulledy described. “The project had to coordinate with both the Colorado Department of Transportation and Union Pacific Railroad to gain clearances. Additionally, the Federal Emergency Management Agency floodplain mapping had to be revised and permitting was needed through the Army Corps of Engineers. The construction required the water flowing in the creek to be pumped around the project for the entire duration of construction. The construction area was very limited and small so the contractor had to create a methodical plan on how to construct the project elements without working themselves into a corner.”
Colorado Springs also has other projects in the works geared toward promoting public and environment safety in how stormwater is conveyed. There are 12 projects with designs underway, which will include various channel stabilizations, drop structures for stream bank protection and a wetland restoration project. Construction is either planned or undergoing for other multiple creek and channel improvements throughout Colorado Springs as well.