Projects>Railroad Creek Habitat Improvement at Holden Mine – Washington
Confluence has been retained by Magnus Pacific Corporation to provide construction planning and stream restoration construction oversight services for the relocation and realignment of Railroad Creek in the Cascade Mountains of Washington. The channel is being relocated as part of a larger Superfund project to separate mine tailings from the active river channel and eliminate metals contamination issues in Railroad Creek and Lake Chelan. The project is being administered jointly by the U.S. Forest Service and the EPA.
Confluence has conducted several hydrologic and hydraulic analyses as part of the construction planning phase including:
• Railroad Creek hydrograph analysis to determine appropriate periods for installing dewatering devices, large woody debris clusters, grade control features, and temporary channel crossings.
• Depth of scour hydraulic calculations to determine appropriate installation methods and depths for large woody debris structures.
• Calculation of seepage, leakage, and infiltration rates for designing a dewatering system capable of complying with State of Washington water quality regulations.
• Hydraulic modeling using WinXSPro to determine depth and velocities of Railroad Creek at various discharges for use in determining levels of risk during construction phases.
• Hydraulic modeling of the proposed Railroad Creek alignment as part of the design of a temporary channel crossing for haul trucks.
Revegetation Planning and Design
Confluence prepared a revegetation plan for establishing woody riparian vegetation along 4,350 feet of Railroad Creek. The revegetation plan included a combination of shrub cuttings and nursery stock installed along various hydrologic regimes extending from the toe of the stream bank up to the 1,000-year flood elevation. The revegetation plan included:
• Techniques for harvesting, rooting, storing, installing, and maintaining woody cuttings
• Table of planting areas, bank length, and re-sloped bank height
• Table of revegetation quantities based on species and planting densities recommended for various hydrologic zones