NSD has led the analysis and design efforts for this project which will address fish passage issues on Mill Creek. NSD worked with project stakeholders including WDFW and Chelan County Public Works to identify suitable design criteria at project initiation. We then led a field assessment and developed a design utilizing WDFW’s stream simulation design approach. We used hydraulic models to develop a design for a replacement culvert which will accommodate the full range of anticipated flows while allowing some uncertainty for climate change. NSD led the engineering and design development to replace the existing 5-foot by 4-foot concrete culvert with a 20-foot structural plate culvert. Construction was completed in 2020.