Mitigation/Monitoring Plan

EXISTING DATA REVIEW 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 2009 Project No. 100002604 Existing Data Review Saltese Flats Wetland Restoration Investigation CONTENTS Page 1.0 INTRODUCTION...............................................................................................................................1 1.1 Purpose and Scope ......................................................................................................................1 2.0 DATA SOURCES AND PREVIOUS INVESTIGATIONS...............................................................5 2.1 Data Sources................................................................................................................................5 2.2 Previous Investigations ...............................................................................................................5 3.0 DATA SUMMARY............................................................................................................................7 3.1 GIS Data Compilation.................................................................................................................7 3.2 Land Use and Ownership ............................................................................................................7 3.3 Topography ...............................................................................................................................12 3.4 Climate ......................................................................................................................................12 3.5 Geology and Soils .....................................................................................................................15 3.5.1 Geology 15 3.5.2 Soils 18 3.6 Wetlands and Associated Habitat..............................................................................................18 3.6.1 Historical Conditions........................................................................................................19 3.6.2 Current Conditions ...........................................................................................................19 3.6.3 Past Preliminary Restoration Options ..............................................................................22 3.7 Surface Water............................................................................................................................23 3.7.1 Flows and Water Level Data............................................................................................25 3.7.2 Surface Water Quality......................................................................................................26 3.8 Groundwater..............................................................................................................................26 3.8.1 Wells and Water Level Patterns .......................................................................................26 3.8.2 Aquifer Description..........................................................................................................31 3.8.3 Water Use 32 3.8.4 Groundwater Quality........................................................................................................35 3.9 Water Rights..............................................................................................................................35 4.0 DATA GAPS AND RECOMMENDATIONS .................................................................................37 5.0 REFERENCES..................................................................................................................................38 APPENDICES APPENDIX A Not Used APPENDIX B USDA Soil Conservation Service Soil Survey Information APPENDIX C Historical Newspaper Articles APPENDIX D Well Information APPENDIX E Water Right Documentation and Map January 2009 ii .00 Existing Data Review Saltese Flats Wetland Restoration Investigation TABLES Table 3-1. GIS Data and Data Sources ........................................................................................................8 Table 3-2. Liberty Lake Sewer and Water District Precipitation Data ......................................................13 Table 3-3. Saltese Flats Flow Estimates ....................................................................................................25 Table 3-4. Shelley Lake Levels 2007-2008 ...............................................................................................25 Table 3-5. Shelley Lake 2007 Water Quality Data....................................................................................26 Table 3-6. Water Purveyor Well Summary ...............................................................................................33 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 3-1. Spokane County Zoning Designations for Saltese Flats .........................................................10 Figure 3-2. Spokane County Parcel Data...................................................................................................11 Figure 3-3. Liberty Lake Sewer and Water District Weather Station Locations .......................................13 Figure 3-4. Spokane Airport and Coeur d’Alene Climatological Data Summary .....................................14 Figure 3-5. Precipitation Cumulative Departure Plots...............................................................................15 Figure 3-6. Precipitation Map (from Kahle et al., 2005) ...........................................................................15 Figure 3-7. Geologic map of the Saltese Flats Area ..................................................................................16 Figure 3-8. Cross-Section Showing Saltese Flats and the SVRP Aquifer (from Golder, 2003)................17 Figure 3-9. Preliminary Restoration Configurations (from Golder, 2004) ................................................22 Figure 3-10. Watershed and Surface Water Related to Saltese Flats.........................................................24 Figure 3-11. Regional Well Locations.......................................................................................................27 Figure 3-12. Near Site Well Locations ......................................................................................................28 Figure 3-13. General Regional Potentiometric Surface Map.....................................................................29 Figure 3-14. Long-Term Groundwater Level Patterns ..............................................................................30 Figure 3-15. Seasonal Groundwater Level Patterns...................................................................................30 Figure 3-16. SVRP Aquifer Boundary.......................................................................................................32 Figure 3-17. Water Purveyor Service Areas ..............................................................................................33 January 2009 iii .00 Existing Data Review Saltese Flats Wetland Restoration Investigation 1.0 INTRODUCTION This document presents a review of available information gathered as an initial step of the Wetland Resto- ration Investigation for Saltese Flats (PBS&J, 2008a and 2008b). This existing information review includes both site-specific data and regional data. 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 functions as wetland today, and also land that historically was a lake/wetland system but has been drained and used for agriculture for over one hundred years. The Saltese Flats Wetland Restoration Investigation has been initiated to evaluate the feasibility of restoring the Flats, or portions thereof, to wetlands. Benefits of the restoration are expected to include an im- provement of flow conditions in Saltese Creek and summer lake levels in Shelley Lake, water releases later in the summer to help increase flow in the Spokane River, improved wildlife habitat, educational and recreation opportunities, and a potential location for the beneficial use of reclaimed water. Restoration feasibility will be evaluated for three main alternatives that include restoring all of Saltese Flats or smaller portions (Figure 1-3). 1.1 Purpose and Scope The purpose of this report is to summarize existing information concerning the Saltese Flats area that is important for evaluating wetland restoration feasibility, including the use of reclaimed water. The available data gathered for this component of the investigation are used to develop an interpretation of site conditions, and also to identify critical data gaps where additional data are needed. The additional data needs will be

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