2007 Upper Yakima River Update
| Title |
Page Number |
|---|---|
| Acknowledgments (PDF) |
i |
| Table of Contents (This Page) |
ii |
| List of Tables |
vii |
| List of Figures |
ix |
| List of Abbreviations |
xi |
| Executive Summary |
ES-1 |
| Comprehensive Flood Hazard Management Planning |
ES-2 |
| 1998 Upper Yakima CFHMP |
ES-3 |
| CFHMP Goals and Objectives | ES-3 |
| 2007 Upper Yakima CFHMP Update |
ES-5 |
| Recommended Actions |
ES-7 |
| Project Implementation Strategy |
ES-13 |
| 1. Introduction (PDF) |
1-1 |
| Background |
1-1 |
| Flooding Issues in Study Area |
1-1 |
| Principles of Flood Hazard Management |
1-2 |
| Authority and Scope for Yakima County CFHMP |
1-2 |
| Plan Development Process |
1-4 |
| Involving the Public and Affected Agencies |
1-4 |
| Defining Goals and Objectives |
1-8 |
| Collecting Data |
1-8 |
| Related Programs or Actions |
1-11 |
| Plan 2015 - Yakima Countys Comprehensive Plan |
1-11 |
| Yakima County Revised Flood Insurance Study |
1-11 |
| Flood Control Assistance Account Program |
1-11 |
| Funding |
1-12 |
| Requirements for CFHMPs |
1-12 |
| Applicant Eligibility |
1-13 |
| Maintenance Project Eligibility |
1-13 |
| Emergency Projects |
1-14 |
| Required Consultation with Other Agencies |
1-14 |
| 2. Study Area Characteristics (PDF) |
2-1 |
| Yakima River Basin |
2-1 |
| Study Area Limits |
2-2 |
| Upper Reach - Yakima Canyon to Selah Gap |
2-2 |
| Middle Reach - Selah Gap to SR 24 Bridge |
2-4 |
| Lower Reach - SR 24 Bridge to Union Gap |
2-5 |
| Physical Characteristics |
2-5 |
| Climate |
2-5 |
| Hydrology |
2-5 |
| Geology |
2-8 |
| Soils |
2-10 |
| Wetlands |
2-11 |
| Fisheries and Wildlife |
2-11 |
| Vegetation |
2-12 |
| Water Quality |
2-13 |
| Socioeconomic Characteristics |
2-15 |
| Jurisdictional Boundaries |
2-15 |
| Population |
2-15 |
| Land Use |
2-16 |
| 3. Previous Studies (PDF) |
3-2 |
| Revised Preliminary Yakima County Flood Insurance Study |
3-2 |
| Estimated Flood Flows |
3-2 |
| Hydraulic Computer Modeling |
3-7 |
| Flood Insurance Rate Maps, Floodway Maps, and Flood Boundary Maps |
3-8 |
| 1970 Floodplain Information; Yakima and Naches Rivers |
3-9 |
| 1973 Floodplain Information; City of Selah and Vicinity |
3-9 |
| 1978 Yakima-Union Gap Flood Damage Reduction Report |
3-10 |
| Alternative 1 - No Action |
3-10 |
| Alternative 2 - Floodplain Management Alone |
3-10 |
| Alternative 3 - Floodplain Management with Additional Flood Control Storage |
3-10 |
| Alternative 4 - Floodplain Management with Levees |
3-12 |
| Alternative 5 - Floodplain Management with Channel Modification |
3-12 |
| Alternative 6 - Purchase of Development Rights |
3-12 |
| Alternative 7 - Purchase of Floodway |
3-12 |
| Recommended Plan |
3-13 |
| 1986 Yakima-Union Gap Flood Control Project |
3-14 |
| 1991 Yakima River Flood Evaluation for Yakima County Diking District No. 1 |
3-14 |
| Estimated Flood Flows |
3-15 |
| Review of Historical Floods |
3-15 |
| Issues Identified as Affecting Flood Risks |
3-16 |
| Assessment of Previous Studies |
3-16 |
| Key Results from Previous Studies |
3-17 |
| Recent Related Studies |
3-18 |
| 1998 Department of Natural Resources Flood Plains, Salmon Habitat, and Sand and Gravel Mining |
3-19 |
| 1998 Department of Natural Resources Reclamation of Flood-Plain Sand and Gravel Pits and Off-Channel Salmon Habitat |
3-19 |
| 1998 Revisions to Yakima County Flood Insurance Study |
3-19 |
| Yakima River Floodplain Mining Impact Study (2002) |
3-19 |
| The Reaches Project Report (2002) |
3-21 |
| SR 24 Project Floodplain Consistency Report (2003) |
3-23 |
| Lower Naches River Coordination Project (2005) |
3-23 |
| Yakima County Mineral Resource Task Force (2006) |
3-26 |
| Conclusions - Additional Ongoing Efforts that Affect Flood Management |
3-27 |
| 2003 Yakima River Basin Water Storage Feasibility Study |
3-28 |
| Subbasin Plan and Salmon Recovery |
3-28 |
| 4. Yakima River Flooding Characteristics (PDF) |
4-1 |
| Common Flood Characteristics |
4-1 |
| Flood Magnitude |
4-1 |
| Flood Duration |
4-2 |
| Channel Migration |
4-3 |
| Sediment Transport and Deposition |
4-4 |
| Effects of Levees |
4-8 |
| Effects of Roads and Bridges |
4-8 |
| Effects of Reservoir Storage |
4-9 |
| Flood History |
4-9 |
| February 9, 1996, Flood |
4-10 |
| November 30, 1995, Flood |
4-14 |
| February 1995 Floods |
4-14 |
| November 26, 1990, Flood |
4-15 |
| December 27, 1980, Flood |
4-18 |
| December 2, 1977, Flood |
4-18 |
| December 4, 1975, Flood |
4-19 |
| January 16, 1974, Flood |
4-19 |
| March 14, 1972, Flood |
4-20 |
| May 29, 1948, Flood |
4-20 |
| December 23, 1933, Flood |
4-21 |
| Summary of Historical Floods |
4-21 |
| Historical Flood Improvement Projects |
4-22 |
| 5. Flood Control Facilities and Programs (PDF) |
5-1 |
| Facilities Inventory |
5-1 |
| Yakima Levee Project |
5-1 |
| Public Law 84-99 Levees |
5-2 |
| Highways |
5-4 |
| Other Flood Control Works |
5-6 |
| Operation and Maintenance |
5-11 |
| Special Districts |
5-11 |
| Other Flood-Related Programs |
5-11 |
| United States Bureau of Reclamation, Yakima Project |
5-12 |
| Yakima Greenway Foundation |
5-13 |
| Yakima River Watershed Council |
5-20 |
| Yakima River Basin Water Enhancement Project |
5-20 |
| Yakima Subbasin Fish and Wildlife Planning Board (YSPB) |
5-21 |
| Yakima Basin Salmon Recovery Board Lead Entity |
5-21 |
| Yakima Basin Fish & Wildlife Recovery Board |
5-21 |
| 6. Regulations (PDF) |
6-1 |
| Summary of Existing Regulations |
6-1 |
| County Regulatory Tools for Flood Hazard Management |
6-8 |
| City of Yakima |
6-11 |
| City of Union Gap |
6-11 |
| City of Selah |
6-12 |
| NPDES Phase II Municipal Stormwater Permits |
6-13 |
| Permitting Requirements |
6-14 |
| SEPA/GMA Integration |
6-14 |
| 7. Alternative Analysis Approach (PDF) |
7-1 |
| Flooding Issue Identification |
7-1 |
| Flood Hazard Management Options |
7-1 |
| Nonstructural Measures |
7-1 |
| Structural Measures |
7-3 |
| Alternative Analysis and Selection |
7-4 |
| Considerations for Evaluating Alternatives |
7-4 |
| Alternative Selection |
7-7 |
| 8. Analysis of Flood Mitigation Alternatives (PDF) |
8-1 |
| LR5 - Aggradation/Reduced Flood Capacity Upstream of SR 24 Bridge; Flood Damage to SR 24 Bridge, Yakima Regional Wastewater Treatment Plant Levee, and DID #1 Levee (1) |
8-3 |
| MR2 - Yakima Beech Street Gravel Pit Levee (2), and UR5 - East Selah Gravel Pit Levee (24) |
8-25 |
| LR3 - Increased Flood Elevation near Union Gap (3) |
8-30 |
| LR7 - Capture of Edler Ponds (4) |
8-37 |
| RW1 - Floodplain Mapping (5) |
8-38 |
| RW20 - Loss of Channel Capacity due to Sediment Accumulation (6) |
8-42 |
| NA1 - Bedload Movement and Channel Instability of Naches River (7) |
8-43 |
| RW13 - Funding for Flood Control Work and Restoration Projects (8) |
8-44 |
| RW6 - Public Disclosure of Floodplain Status (9) |
8-45 |
| RW12 - Protection of State and County Roads (10) |
8-46 |
| RW3 - Channel Migration (11), LR1 - Erosion of Agricultural Lands (15), and UR1 - Erosion of Agricultural Land (22) |
8-49 |
| RW9 - Diversity of Opinions Relating to River Management (12), and RW8 - County Policy on Flood Hazard Management (17) |
8-50 |
| RW4 - Flood Hazard Ordinance (13), and RW5 - Revision and Consistency of Critical Areas Ordinance (25) |
8-51 |
| RW2 - Loss of Fisheries Habitat and Riparian Areas (14), and MR8 - Borrow Pit Levee Upstream of Terrace Heights Bridge (31) |
8-61 |
| RW17 - Existing Structures in the Floodplain (16) |
8-64 |
| RW16 - Operation and Maintenance of Flood Control Facilities (18) |
8-67 |
| RW10 - Acquisition/Preservation of Floodplain Open Space (19) |
8-70 |
| RW19 - Flood Warning and Emergency Response (20) |
8-73 |
| RW18 - Community Rating System (21), and RW7 - Flood Insurance and Public Education (28) |
8-79 |
| RW15 - Use of Geographic Information (GIS) Data (23) |
8-84 |
| OSA1 - Continued Flood Damage Outside the CFHMP Study Area (26) |
8-88 |
| MR6 - Flood Damage to Greenway path Near Boise Cascade Pond (32) |
8-89 |
| LR6 - Spring Creek Backwater Flooding (29) |
8-92 |
| MR7 - Flood Damage to Robertson Landing (30), UR3 - Flood Damage to Harlan Landing (33), and UR4 - Inundation of Elks Golf Course (34) |
8-94 |
| 9. Funding Options (PDF) |
9-1 |
| Funding Sources |
9-2 |
| County Administrative Options |
9-2 |
| External Funding Sources |
9-10 |
| Funding Source Evaluation |
9-23 |
| Evaluation Criteria |
9-23 |
| Programs to be Funded |
9-24 |
| Large Project Funding Strategy |
9-27 |
| References (PDF) |
R-1 |
Appendices
- A. July 22, 2005 SEPA Final Mitigated Determination of NonSignificance (PDF)
- A. Yakima County Flood Control District’s Response to Mitigated Determination of Non-Significance
- B. Issues contained in the 1998 Upper Yakima CFHMP (PDF)
- C. Flood Inundation Map - Map C-3 South Section (PDF)
- D. Flood Control Works Inventory - Map D-1 Overview Of Levees Within the Planning Area (JPG)
- D. Flood Control Works Inventory - Map D-2 Federal Project Levees – Right Bank Upper (PDF)
- D. Flood Control Works Inventory - Map D-3 Federal Project Levees – Right Bank Lower (PDF)
- D. Flood Control Works Inventory - Map D-4 Federal Project Levees – Left Bank (PDF)
- D. Flood Control Works Inventory - Table - Status of Inventoried Levees (PDF)
- E. Advisory Committee Voting Results (PDF)
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