Ralston Creek Improvements
Watch this YouTube video to learn more from the project managers.
- Re-aligned Ralston Creek
- Soft surface trail
- Recreational logs + boulders
- Re-aligned multi-use path
- Seating / gathering area
- New pedestrian bridge
- Existing trees to remain
- Planted trees
- Secondary channel
- River stability structure with seating
View A: Looking west from bridge
View B: Looking southeast from multi-use trail
View C: Looking east from creek
- April 2023: Pre-construction tree clearing of dead and overgrown trees.
- These trees pose a significant flood risk in the area.
- Environmental consultants and ecologists conduct bird and nest surveys to identify trees that cannot be removed to protect wildlife.
- No active bird nests were observed throughout the study area or within 50 feet of the study area. No active raptor nests were observed throughout the study area or within 0.5 miles of the study area.
- Quarter (Q)1 2023: Pre-construction tree clearing (complete)
- Q3 2022 to Q3 2023: 60% Design, Environmental Survey and Permits, and Floodplain Permits (in progress)
- Q4 2023: Final Design and Permit Approvals*
- Q1 to Q2 2024:Construction*
- Trail closures will be necessary during construction (more information will be made available)
- Approximately 5 to 6 months of construction
- Q2 / Q3 2024: Re-vegetation and plantings*
*Timelines are approximate and dependent on weather and permit approval processes.
- Remove dead and down trees, invasive tree species, and thick vegetation that are impeding the flow of water during heavy rainfall or flooding events
- Facilitate the natural movement of water
- Analyze where the channel improvement grading will significantly disrupt the tree canopy zone or directly affect the tree trunk and thus the well-being and longevity of trees
- Mitigate potential harm to the existing tree root systems, structural integrity, and overall health of the trees to remain
- Prioritize public safety and minimize the risk of potential accidents or damage to property
- Proactively identify and remove aged or diseased trees that are susceptible to structural weakness and could pose a threat to public safety if their branches or entire trees were to fall during severe weather conditions
- Mitigate the spread of diseases or pests that can harm the overall tree population
- Removing infected or infested trees to protect the health of the remaining trees and preserve the overall ecological balance
- Removing invasive species that could impact native biodiversity
- Plant new trees and vegetation to provide wildlife habitat, restore the floodplain ecosystem, and enhance the area’s natural beauty
- Create a recreational play area using the logs from removed trees to allow for community interaction with the creek and ecosystem
- Improve the layout of the existing multi-use path to have better visibility with wide turns and remove overgrown vegetation blocking views
- Provide a safer bike and pedestrian route through the area
Additional Background Information
Prior to this work beginning, the City team evaluated multiple options for how to best mitigate the flood risk through this corridor.
The current state of the creek had flood carrying capacity for a 2 to 10-year flood event (10 to 50% chance in any given year). The creek should be designed for a 25 to 100-year event (1 to 4% chance in any given year).
The project is designed to have flood carrying capacity for a 25-year event, based on the following factors:
- Mitigation of impacts and disturbance to the tree and creek environment
- Flooding risk to the surrounding homes, infrastructure, trees and stream
- Cost and resource allocation for the project
- Impacts to FEMA floodplain elevations
The project team went through several iterations of design to try to avoid tree removal. However, due to the proximity of these trees to the creek it was deemed necessary to remove trees to realign and restore the stream corridor.
Replanting and Revegetation
The area will be restored with replacement trees and natural features once construction is complete in spring 2024. Revegetation will be designed in a manner that is more sustainable to the possible flooding events, including the replanting of trees in safer locations.
Tree replacement and revegetation is not a one for one replacement. Often, replacement results in more trees and vegetation to revitalize an area.