Final Conceptual Designs

WETLAND RESTORATION CONCEPTUAL DESIGNS REPORT SALTESE FLATS WETLAND RESTORATION INVESTIGATION Spokane County, Washington Prepared for: SPOKANE COUNTY DIVISION OF UTILITIES PUBLIC WORKS BUILDING 1026 W. BROADWAY AVE. SPOKANE WA 99260 Prepared by: 1120 Cedar Street Missoula, MT 59802 March 2010 Project No. 100002604 Wetland Restoration Conceptual Designs Report Saltese Flats Wetland Restoration Investigation CONTENTS Page 1.0 INTRODUCTION ............................................................................................................................... 1 1.1 Purpose and Scope ...................................................................................................................... 5 1.2 Wetland Restoration Feasibility Overview ................................................................................. 5 2.0 CONCEPTUAL DESIGNS OVERVIEW .......................................................................................... 9 2.1 Conceptual Design Areas ............................................................................................................ 9 2.2 Restoration with Natural Hydrology ........................................................................................... 9 2.3 Restoration with Reclaimed Water .............................................................................................. 9 2.4 Potential Restoration Components and Concerns Common to ................................................. 10 All Concepts ...................................................................................................................................... 10 3.0 RESTORATION SCENARIOS ........................................................................................................ 18 3.1 Restoration to the Original Lake ............................................................................................... 18 3.2 Inundated Wetlands on Option Areas A and B ......................................................................... 20 3.3 Multiple Wetlands ..................................................................................................................... 22 3.4 Multiple Wetlands with Enhancements ..................................................................................... 24 3.5 Wetland/Crop Combination ...................................................................................................... 26 3.6 Visualizations ............................................................................................................................ 28 4.0 COSTS AND FUNDING .......................................................................................................... 33 5.0 NEXT STEPS ................................................................................................................................... 40 6.0 SUMMARY AND CONCLUSIONS ................................................................................................ 40 7.0 INFORMATION SOURCES ............................................................................................................ 41 APPENDICES APPENDIX A Cost Estimate Assumptions March 2010 ii .00 Wetland Restoration Conceptual Designs Report Saltese Flats Wetland Restoration Investigation TABLES Table 4-1. Saltese Flats Restoration: Natural Hydrology Cost Estimates .................................................. 34 Table 4-2. Saltese Flats Restoration: Reclaimed Water Cost Estimates .................................................... 35 Table 4-3. Saltese Flats Restoration: Permitting and NEPA/SEPA Cost Estimates .................................. 36 Table 4-4. Saltese Flats Restoration: Construction-Option Area A ........................................................... 37 Table 4-5. Saltese Flats Restoration: Construction-Option Area B ........................................................... 38 Table 4-6. Saltese Flats Restoration: Maintenance & Monitoring-Option Area A .................................... 39 FIGURES Figure 1-1. Saltese Flats Location................................................................................................................ 2 Figure 1-2. Saltese Flats Watershed Delineation ......................................................................................... 3 Figure 1-3. Saltese Flats Restoration Options .............................................................................................. 4 Figure 1-4. Saltese Flats Existing Features .................................................................................................. 8 Figure 2-1. Potential Berm and Shoreline Examples ................................................................................. 12 Figure 2-2. Public Access and Potential Trail System ............................................................................... 14 Figure 3-1. Restoration to Original Lake ................................................................................................... 19 Figure 3-2. Inundated Wetlands ................................................................................................................. 21 Figure 3-3. Multiple Wetlands ................................................................................................................... 23 Figure 3-4. Multiple Wetlands With Enhancements .................................................................................. 25 Figure 3-5. Wetland/Crop Option .............................................................................................................. 27 Figure 3-6. Option A Area Scenarios From Viewpoint 1 .......................................................................... 29 Figure 3-7. Option A Area Scenarios From Viewpoint 2 .......................................................................... 30 Figure 3-8. Option B Area Scenarios From Viewpoint 1 .......................................................................... 31 Figure 3-9. Option B Area Scenarios From Viewpoint 2 .......................................................................... 32 March 2010 iii .00 Wetland Restoration Conceptual Designs Report Saltese Flats Wetland Restoration Investigation 1.0 INTRODUCTION The Spokane County Division of Utilities is currently evaluating potential wetland restoration opportunities at Saltese Flats. The Saltese Flats wetland restoration project could provide a variety of benefits including: • Delaying runoff to recharge the Spokane Valley-Rathdrum Prairie Aquifer to increase flow in the Spokane River during late summer months; • Restoring a diverse wildlife habitat area; • Providing a community resource for public recreation and education; and • Allowing for possible future beneficial use of Class A reclaimed water. This document presents and discusses a series of conceptual designs for wetland restoration options at Saltese Flats. Saltese Flats is located in Spokane County southeast of the city of Spokane Valley (Figure 1-1). The area known as Saltese Flats occupies roughly 1,200 acres of land that lies within a watershed of approximately 14,000 acres (Figure 1-2). The Flats includes land that currently functions as wetland, and also land that historically was a lake/wetland system but has been drained and used for agriculture for over one hundred years. Three wetland restoration option areas were considered during initial evaluation at Saltese Flats (Figure 1-3). Option Area A is 342 acres, Option Area B is 512 acres and Option Area C is approximately 1,200 acres. This report summarizes restoration opportunities on Option Areas A and B. These areas were determined to be sufficiently large to accommodate wetland restoration using both natural hydrology and reclaimed water (PBS&J, 2010), and directly involve only two landowners. Wetland restoration is also feasible on other lands within Option Area C and could be undertaken in coordination with efforts on Option Areas A and B, or separately over time in response to landowner interest. Option Area C includes many landowners. This document represents the completion of the fourth phase of the Saltese Flats investigation completed by PBS&J under contract with the Spokane County Division of Utilities (Spokane County Utilities) in coordination with the WRIA 55/57 Watershed Implementation Team (WRIA 55/57 WIT), and with funding from the Washington State Department of Ecology (Ecology). Previous phases include: 1. Development of a Scope of Work (PBS&J, 2008a) with subsequent update upon the completion of initial tasks (PBS&J, 2008e); 2. Development of Goals and Objectives for the project (PBS&J, 2008b); 3. A public meeting held on October 15, 2008 to introduce the project to interested parties, and a series of meetings with the WRIA 55/57 WIT and a group known as the Wetland Panel, which was formed from a collection of stakeholders for this investigation; 4. Development of a Quality Assurance Program Plan, or QAPP (PBS&J, 2008c) and a Monitoring Program Plan (PBS&J, 2008d); 5. Completion of an evaluation and summary of existing information, including a preliminary site characterization and documentation in an Existing Data Review report (PBS&J, 2009); 6. Initiation of the Monitoring Program; and 7. Completion of a Data Update and On-Site Feasibility Report (PBS&J 2010). March 2010 1 .00 Wetland Restoration Conceptual Designs Report Saltese Flats Wetland Restoration Investigation Figure 1-1. Saltese Flats Location March 2010 2 .00 Wetland Restoration Conceptual Designs Report Saltese Flats

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