|
|
|
|
Ecology Publications & Forms |
|
|
|
|
|
Ecology Publications & Forms |
| Title |
Chehalis Basin Local Action Non-Dam Alternative (LAND) Conceptual Alternatives Analysis Report |
||||||
|
|||||||
| VIEW NOW |
Chehalis Basin Local Action Non-Dam Alternative (LAND) Conceptual Alternatives Analysis Report (Number of pages: 117) (Publication Size: 4674KB)
Appendix A - Maps Packet and Supplemental Analysis Results (33 pages) (19MB) Appendix B - Basis of Analysis (18 pages) (553KB) Appendix C - Cost Tables (3 pages) (144KB) Appendix D - Numerical modeling Summary (14 pages) (2MB) Appendix D.1.1 - Screening Level Model Results (7 pages) (392KB) Appendix D.1.2 - I1D Modeling (33 pages) (3MB) Appendix D.2.1 - 2D Numerical Model Results (9 pages) (1MB) Appendix D.2.2 - Annex A Maps and Timeseries (76 pages) (10MB) Appendix E - Geotechnical Reports (23 pages) (1MB) Appendix E.2 - Geotechnical Appendices (34 pages) (21MB) Appendix F - Environmental Analysis Memo (32 pages) (2MB) Appendix G - Transportation Impacts and Opportunites (9 pages) (1MB) Appendix H - Trails and Parks (35 pages) (1MB) Appendix H.2 - Trails and Parks Appendices (8 pages) (12MB) Appendix I - China Creek Daylighting (5 pages) (204KB) Appendix I.2 - China Creek Daylighting Appendices (6 pages) (4MB)
|
||||||
| Author(s) | Moffat & Nichol | ||||||
| Description | This study was completed by the Office of Chehalis Basin (OCB), housed within the Washington State Department of Ecology, and includes Phase 2 conceptual design work completed as part of the Chehalis Basin Local Actions Non-Dam (LAND) Alternatives Analysis. This study aims to reduce flood damage to communities across the Chehalis Basin by building upon the Phase 1 LAND work completed in 2024 by OCB. Phase 2 of the LAND study focused on refining conceptual designs for structural flood protection features, including levees, floodwalls, and conveyance improvements. The analysis was conducted in two phases – first a concept-level screening analysis and stakeholder coordination effort was conducted to refine the features from Phase 1 of LAND. The concept level screening removed the diversion component of the project due to cost, environmental, and stakeholder concerns. The screening process also included analysis of different levee and floodwall alignments and developed potential phased construction scenarios. Following the concept screening analysis, two-dimensional hydraulic modeling (RiverFLOW2D) was conducted to assess potential water level and velocity changes resulting from construction of the conceptual flood protection features. The model results showed relatively minimal downstream increases in water level and identified isolated areas of morphological risk for further analysis in future phases of the study. The estimated project costs range from $850 million to $1.5 billion (2025 dollars), including a 55 percent contingency. Future phases of LAND should advance the conceptual designs identified herein through conducting geotechnical investigations, refining hydraulic models, integrating the LAND components with other studies in the basin, and including other recommendations noted in the main report. |
||||||
| REQUEST A COPY |
The mission of the Department of Ecology is to protect, preserve, and enhance Washington's environment. To help us meet that goal, please consider the environment before you print or request a copy.
ADA Accessibility The Department of Ecology is committed to providing people with disabilities access to information and services by meeting or exceeding the requirements of the Americans with Disabilities Act (ADA), Section 504 and 508 of the Rehabilitation Act, and Washington State Policy #188. Visit Ecology’s website for more information |
||||||
| Contact | Nat Kale, OCB Principal Planner at 360-706-4277 or Nat.Kale@ecy.wa.gov | ||||||
| Keywords | Office of Chehalis Basin, Local Actions Non-Dam (LAND) Alternative, OCB | ||||||
| DISCLAIMER | This material was not produced by the Department of Ecology, but is directly related to the agency's work. |
Copyright © Washington State Department of Ecology. See https://ecology.wa.gov/About-us/Accountability-transparency/Our-website/Copyright-information.
|