DATA UPDATE AND ON-SITE FEASIBILITY 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 5802

15320 East Marietta Ave, Suite 9A Spokane Valley, WA 99216-1870

January 2010

Project No. 100002604

Data Update and On-Site Feasibility Report Saltese Flats Wetland Restoration Investigation

CONTENTS Page

1.0 INTRODUCTION ...... 1 1.1 Purpose and Scope ...... 1 1.2 Additional Data Sources ...... 5 2.0 ADDITIONAL DATA SUMMARY ...... 6 2.1 Topographic Surveys...... 8 2.2 Photographic Documentation ...... 9 2.3 Meteorological Data Compilation ...... 10 2.4 Soil Borings and Well Installations ...... 12 2.5 Wetland Delineation ...... 12 2.6 Surface Water Stage and Discharge ...... 16 2.7 Water Management at Saltese Flats ...... 22 2.8 Groundwater Levels ...... 24 2.9 Water Quality ...... 27 3.0 WATER BUDGET ...... 32 3.1 Methodology ...... 32 3.2 Water Budget Scenarios ...... 34 3.3 Shelley Lake and Gravel Pit Infiltration ...... 41 4.0 RESTORATION FEASIBILITY SCREENING ...... 44 4.1 Restoration Scenario Alternatives ...... 44 4.2 Screening Criteria ...... 44 4.3 Option A Alternatives ...... 44 4.4 Option B Alternatives ...... 45 4.5 Option C Alternatives ...... 46 4.6 Preferred Restoration Alternatives ...... 46 4.7 Review of Washington State Reclaimed Water Use Standards ...... 46 5.0 CONCLUSIONS AND RECOMMENDATIONS ...... 48

6.0 REFERENCES ...... 50

APPENDICES

APPENDIX A Topographic Maps APPENDIX B Example Photographic Documentation APPENDIX C Soil Boring Logs APPENDIX D Analytical Data and Laboratory Reports APPENDIX E Wetland Delineation Maps, Forma, and Photos APPENDIX F Surface Water Levels and Discharge Data and Groundwater Elevation Data APPENDIX G Water Budget Scenarios

January 2010 ii .00 Data Update and On-Site Feasibility Report Saltese Flats Wetland Restoration Investigation

TABLES

Table 2-1. Annual Precipitation at Liberty Lake ...... 10 Table 2-2. Monthly Precipitation at Pine Terrace, Spokane, and Coeur d’Alene ...... 10 Table 2-3. Cowardin Vegetation Types Within Routine Mapping Areas ...... 13 Table 2-4. Cowardin Vegetation Types Within Reconnaissance Mapping Areas ...... 14 Table 2-5. Surface Water Monitoring Locations ...... 17 Table 2-6. Discharge Comparison Between Saltese Flats and Liberty Creek...... 18 Table 2-7. Saltese Flats Flow Estimates ...... 22 Table 2-8. Preliminary Annual Groundwater Level Fluctuation Estimates ...... 26 Table 2-9. Offsite Well Summary ...... 27 Table 2-10. Synoptic Nutrient Sampling Results for Saltese Flats ...... 29 Table 3-1. Average Outflow (cfs) from Saltese Flats by Modeling Scenario ...... 35 Table 3-2. Average Outflow (Ac-Ft) from Saltese Flats by Modeling Scenario ...... 35 Table 3-3. Summary of Shelley Lake Infiltration Rate Calculations ...... 42

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 2-1. Regional Monitoring and Data Source Locations ...... 6 Figure 2-2. Saltese Flats Monitoring and Data Source Locations ...... 7 Figure 2-3. Saltese Flats Photo-Point Locations ...... 9 Figure 2-4. Average Monthly Precipitation at Stations Surrounding Saltese Flats ...... 11 Figure 2-5. Precipitation Cumulative Departure Plots ...... 11 Figure 2-6. Watershed and Surface Water Related to Saltese Flats ...... 16 Figure 2-7. Liberty Creek Discharge Data ...... 18 Figure 2-8. Liberty Creek Discharge Data ...... 19 Figure 2-9. Water Levels for Liberty Creek and Saltese Flats Inlets ...... 19 Figure 2-10. Water Levels for Shelley Lake and Saltese Flats Outlets...... 20 Figure 2-11. Water Levels for Shelley Lake and Saltese Flats Outlets...... 21 Figure 2-12. Saltese Flats Water Management Features ...... 23 Figure 2-13a. Shallow Groundwater Elevatio