Stream Buffer Evaluation Report

Transcription

1 Stream Buffer Evaluation Report Snoqualmie Switch Station Improvements Snoqualmie, Washington for Puget Sound Energy February 23, 2016 Earth Science + Technology

2 Stream Buffer Evaluation Report Snoqualmie Switch Station Improvements Snoqualmie, Washington for Puget Sound Energy February 23, South Fawcett Avenue, Suite 200 Tacoma, Washington

3 Stream Buffer Evaluation Report Snoqualmie Switch Station Improvements Snoqualmie, Washington File No February 23, 2016 Prepared for: Puget Sound Energy th Avenue NE, PSE-04E Bellevue, Washington Attention: Jeff McMeekin Prepared by: GeoEngineers, Inc South Fawcett Avenue, Suite 200 Tacoma, Washington Jennifer L. Dadisman, PWS Staff Biologist Joseph O. Callaghan, MS, PWS Associate Biologist JLD:JOC:ab Disclaimer: Any electronic form, facsimile or hard copy of the original document ( , text, table, and/or figure), if provided, and any attachments are only a copy of the original document. The original document is stored by GeoEngineers, Inc. and will serve as the official document of record.

4 Table of Contents INTRODUCTION... 1 Project Location... 1 Site Description... 1 PROJECT DESCRIPTION... 1 Minimization Measures... 1 DATA REVIEW... 2 METHODOLOGY... 2 FIELD INVESTIGATION... 3 Wetland and Stream Delineation... 3 ASSESSMENT OF PROJECT EFFECTS... 5 BUFFER MITIGATION PLAN... 5 Goals and Objectives... 6 Buffer Enhancement... 6 Invasive Species Control... 6 Planting Plan... 6 Functional Analysis of the Buffer... 7 MAINTENANCE, MONITORING AND CONTINGENCY... 7 Maintenance... 7 Monitoring Plan... 8 Performance Standards... 8 As-Built Design Report... 9 Monitoring Stations... 9 Data Collection... 9 Monitoring Reports and Schedule Contingency Plan CONCLUSIONS LIMITATIONS REFERENCES LIST OF FIGURES Figure 1. Vicinity Map Figure 2. OHWM and Buffer Location APPENDICES Appendix A. Site Photographs Appendix B. Mapped Data Appendix C. Lanscape Plan February 23, 2016 Page i File No

5 INTRODUCTION GeoEngineers, Inc. (GeoEngineers) was contracted by Puget Sound Energy (PSE) to provide critical areas reporting and construction support for the Snoqualmie Switch Station Improvements project. As part of this project, stormwater improvements are proposed within the facility that includes installation of a pipe to collect stormwater and release it to an existing outfall that discharges to the Snoqualmie River. Our critical area evaluation services included performing habitat evaluations on the area where the pipe is proposed. The project is located approximately 500 feet above the Snoqualmie River Falls in Snoqualmie, Washington (Figure 1 - Vicinity Map). This report was completed, in part, to identify and address requirements of the City of Snoqualmie (City) Municipal Code (SMC) Title 19 (Environment), Chapter (Sensitive Areas). Project Location The project is located at the existing Snoqualmie Switch Station located south of Railroad Avenue, in Snoqualmie, Washington. The site is approximately 500 feet above the Snoqualmie River Falls, on the northern bank of the river. See Figure 1 for the site location on the Vicinity Map. The project area is located within Section 30 of Township 24 North and Range 08 East of the Willamette Meridian (W.M.). Our critical areas evaluation services included performing habitat evaluations on the area where the pipe is proposed. This area is partially located within the Snoqualmie River buffer. Figure 2 depicts the buffer and project vicinity. Site Description The project site is situated in a developed area. The switch station is located on top of a hill, and the southern area slopes down steeply to a paved road used by PSE for maintenance of the Snoqualmie Falls facility. The steep sloped area, south of the substation is mainly composed of Himalayan blackberry (Rubus armeniacus). South of the paved road a small, approximately 20- to 40-foot riparian buffer exists that is composed of invasive species and young forested vegetation such as Douglas fir (Pseudotsuga menziesii), red alder (Alnus rubra), Himalayan blackberry, and scotch broom (Cytisus scoparius). Appendix A contains photographs of the project site and vicinity. PROJECT DESCRIPTION As part of the overall improvements, the project includes installing a catch basin and vault for stormwater collection and installing an 18-inch-diameter high-density polyethylene (HDPE) pipe to direct the stormwater from the vault into an existing catch basin down slope of the switching station. This pipe will be partially located within the Snoqualmie River buffer. Minimization Measures Minimization measures and best management practices (BMPs) will be utilized during project activities to avoid impacts to critical area habitats. Conservation measures will focus on minimizing construction noise and the possibility of spills, preventing soil erosion, and minimizing impacts to riparian vegetation. Special measures will be taken to ensure that: all waste materials will be disposed of offsite and in accordance with applicable regulations; adequate materials and procedures are readily available on the site to respond to unanticipated weather conditions or accidental releases of materials; and that a protocol for contacting February 23, 2016 Page 1 File No

6 Washington State Department of Ecology (Ecology) is readily available in the event that water quality problems occur. DATA REVIEW Environmental maps of the project area were collected and reviewed as part of a review of published data. The United States Fish and Wildlife Service (USFWS) National Wetlands Inventory (NWI) online mapper does not show wetland habitat on the project site. The river in the vicinity of the project is mapped as a lacustrine unconsolidated bottom system that is permanently flooded (L1UBH) (USFWS, 2016). The United States Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS) Web Soil Survey indicates one soil type on the property: Barneston gravelly ashy course sandy loam, 0 to 8 percent slopes (USDA-NRCS, 2013). Barneston gravelly ashy course sandy loam soils are not hydric but do contain hydric inclusions (USDA-NRCS, 2015). NWI and soil survey information are included in Appendix B. Additional information was obtained from the Washington State Department of Natural Resources (DNR) Forest Practices Application Review System (FPARS), and Washington State Department of Fish and Wildlife (WDFW) Priority Habitat and Species (PHS) mapping application (DNR, 2015; WDFW, 2016). Both PHS and DNR map the Snoqualmie River at the project site (DNR, 2015; WDFW, 2016). DNR types this stream as Type S waterbody and PHS maps rainbow trout (Oncorhynchus mykiss), cutthroat trout (Oncorhynchus clarki) and Dolly Varden/bull trout (Salvelinus malma) within the river (DNR, 2015; WDFW, 2016). The Snoqualmie River flows north and west and eventually discharges into the Snohomish River (DNR, 2015). The King County IMap (King County, 2016) was also reviewed; the IMap depicts the Snoqualmie River but does not map wetland habitat on, or adjacent to, the project site. METHODOLOGY The identification of aquatic critical areas (wetlands and streams) was conducted in accordance with guidelines presented in SMC Title 19, Chapter (Sensitive Areas). The Washington State Wetlands Identification and Delineation Manual (Ecology, 1997), the U.S. Army Corps of Engineers (USACE) Wetlands Delineation Manual (Environmental Laboratory, 1987) and the Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (USACE, 2010) were used to identify potential wetland habitat. Wetland buffer widths were identified from SMC (G), which specifies wetland buffer widths based on the wetland category and land use intensity. The Ordinary High Water Mark (OHWM) is used to define the jurisdictional boundary of streams and rivers according to the Clean Water Act, Washington State Growth Management Act, Washington State Shoreline Management Act, and local critical areas ordinances. The OHWM of streams is typically evaluated by examining breaks in the topography, drift lines, shifts in vegetation and signs of water marks, according to USACE protocol as referenced from Regulatory Guidance Letter (No ), OHWM Identification, (Riley, 2005). The Washington Administrative Code (WAC) was also referenced for the definition of OHWM (WAC ). Due to the high water levels of the season affecting typical OHWM indicators, the OHWM was not identified in the field and instead the ordinary high water (OHW) level elevation was identified by PSE. February 23, 2016 Page 2 File No

7 In addition, streams are classified based on SMC (A), which divides streams into three classes based on fish use and stream type. Stream buffer widths are identified based on stream classification according to SMC (D). The City of Snoqualmie will make the final determination of buffer widths. FIELD INVESTIGATION Wetland and Stream Delineation A GeoEngineers biologist conducted a field assessment on February 9, 2016 to characterize wetland and stream features within the project area. Representative photographs of the site have been included within this report and in Appendix A. Wetland habitat was not identified within the project site. Figure 2 depicts the buffer of the Snoqualmie River within the project area. As discussed above, no wetland habitat was identified within, or adjacent to, the project site. The Snoqualmie River buffer is disturbed and contains riprap adjacent to the river, paved roads, and existing vegetation is predominantly composed of invasive species such as Himalayan blackberry. The area where the pipe will be located (Appendix A, Photographs 1 and 2), is dominated by Himalayan blackberry. Native vegetation will not be removed from the buffer as a result of the stormwater project. Table 1 on the following page summarizes information regarding the Snoqualmie River features within the area of investigation. February 23, 2016 Page 3 File No

8 TABLE 1. SNOQUALMIE RIVER Snoqualmie River Information Location WRIA Local Jurisdiction DNR Stream Type Snoqualmie Stream Type 500 feet above the falls 7 Snohomish City of Snoqualmie Shoreline I 1 Buffer Width 100 feet 2 Average Channel Width Gradient Duration 230 feet 3 0 to 3 percent Perennial Description Summary Documented Fish Use Connectivity Channel Description Riparian/Buffer Condition Rainbow trout (Oncorhynchus mykiss), cutthroat trout (Oncorhynchus clarki) and Dolly Varden/bull trout (Salvelinus malma) 4. Flows north and west and eventually discharges to the Snohomish River. Sediments, gravels and sands. The Snoqualmie River buffer is disturbed and contains riprap adjacent to the river, paved roads, and existing vegetation is predominantly dominated by invasive species such as Himalayan blackberry. There is a small forested strip (approximately 20 to 40 feet wide) adjacent to the river. This forested strip is composed of young Douglas fir and red alder trees with an understory dominated by invasive species. Notes: 1. SMC Chapter A stream is mapped by DNR FPARS as being a shoreline of the state at the project area. WDFW maps this portion of the stream as containing salmonid species. 2. SMC Chapter (D) ( Stream Buffers ). 3. Average Channel Width derived from GoogleEarth measurements. 4. Washington State Department of Fish and Wildlife (WDFW) PHS data (WDFW, 2016). February 23, 2016 Page 4 File No

9 ASSESSMENT OF PROJECT EFFECTS As a result of the proposed project, the potential stream effects will be minor. The project will not affect stream hydrology and flood storage capacity will not change because the site will be restored to pre project conditions after installation of the pipe. In addition, no work will be completed in stream channel. Project effects that are expected to occur as a result of the project will be from the installation of the 18-inch HDPE pipe. The pipe is proposed within a portion of the Snoqualmie River buffer that is dominated by invasive species. There will be no work conducted below the OHWM of the river. The 18-inch pipe will be placed on the existing grade and lie on the surface. The pipe will be connected to the outfall at the bottom of the slope below the switch station. Effects of the proposed action are defined as the direct and indirect effects of an action on the species or critical habitat, together with the effects of other activities that are interrelated or interdependent with the action, that will be added to the environmental baseline (50 CFR ). Project-related effects are confined to the project area. This section provides an analysis of the anticipated effects. The following effects would likely occur for the proposed project: Construction Related Noise. Construction activity and noise in excess of background conditions generated during the project could permeate terrestrial habitats around the project site. This effect will be temporary in nature and will not persist upon project completion. Water Quality Degradation. Water quality degradation is limited to the footprint of the project and is considered to be a temporary effect. Hazardous Material Spills. Potential impacts to water quality, such as spilling hazardous materials or petroleum based products associated with construction machinery, will be controlled through proper implementation of BMPs and are, therefore, not expected to have negative impacts on the environment. Sediments. There is potential for temporary water quality impacts to occur as a result of fine sediments traveling away from the project if sediments are released into the stream. Any potential impacts are expected to be temporary and minor and will be controlled through proper implementations of the temporary erosion and sedimentation control (TESC) plan. Habitat Alteration. Habitat alteration will be limited to the actual footprint of the project, which for the project, will occur within an area with no trees and only dominated by Himalayan blackberry. Also, as part of the proposed project, a landscape plan has been developed along the southern steep slope; approximately 1,500 square feet of buffer will have invasive species removed and tree and shrub species will be installed. Appendix C contains the landscape planting plan for the project. Buffer Impacts. Approximately 75 square feet (50 feet long by 1.5 feet wide) of buffer habitat will be disturbed as a result of the proposed stormwater pipe alignment. The buffer impacts are minimal because the area is dominated by Himalayan blackberry, and the area where vegetation is removed will be re-planted with a native vegetation community. BUFFER MITIGATION PLAN The buffer habitat restoration of the impact area will include overplanting of the impact area with native species. Approximately 1,500 square feet of buffer will be enhanced (invasive species removal and replanting with trees and shrubs) to compensate for approximately 75 square feet of buffer impacts. February 23, 2016 Page 5 File No

10 Appendix C contains the landscape planting plan that is proposed as mitigation for this project. The landscaping plan will mitigate for potential effects from loss of vegetation and disturbance to the buffer. Invasive plant species will be removed and trees and shrubs will be installed in the disturbed areas. The number of plants to be installed and the locations are depicted in the landscape plan prepared for the project (Appendix C). Goals and Objectives Buffers, in good condition, should perform many functions that include: water quality, thermal cover and temperature moderation for aquatic species and habitat features such as food, cover, nesting, perches and wildlife corridors. Baseline conditions are currently degraded within the buffer and many of these functions could be improved. Re-planting the buffer with tree and shrub species will offset project impacts through compensatory gains in buffer functions. This will include installing habitat enhancements such as shrubs and trees in the mitigation site, which can slow and detain water flow that otherwise may flood the Snoqualmie River channel and cause erosional damage to downstream areas. These actions will be performed with the following specific objectives for the buffer: Increase the potential to improve hydrologic functions; Increase the potential to improve water quality functions; Increase the vegetative diversity; and Increase the habitat structure for the buffer. Buffer Enhancement Approximately 1,500 square feet will be replanted with trees and shrubs to compensate for impacts associated from the proposed project. The buffer enhancement activities within this mitigation plan will be accomplished through the following actions: Initial removal of invasive plant species; and Install appropriate tree and shrub vegetation in the buffer habitat. Invasive Species Control Invasive species identified within the mitigation area included Himalayan blackberry. These invasive plants will be removed and tall growing species, capable of providing shade, will be planted throughout the mitigation site. Planting Plan Proposed planting areas and species are identified in the landscape planting plan within Appendix C. Planting activities should generally follow (as applicable) and be timed as follows: 1. Remove invasive and non-native species, and remove debris as needed. 2. Amend area with clean soils as needed. 3. Conduct the planting immediately after soil amendments are placed and in conjunction with the clearing and removal of debris. This will minimize re-growth of invasive species in newly opened or cleared areas. February 23, 2016 Page 6 File No

11 4. Ideally, planting should be conducted in the early spring or late fall during the dormant season. Staging areas for plants should occur in upland areas. 5. Install tree guards as needed around newly installed vegetation to discourage grazing/browsing by deer and rodents. 6. Add mulch as indicated on the landscape plan (Appendix C). 7. Hand water newly planted areas as needed. 8. Conduct regular maintenance and monitoring as described in the Maintenance, Monitoring and Contingency section of this report. Functional Analysis of the Buffer Once the goals and objectives of this mitigation plan are met through implementation of the plan, functions and values of the buffer are expected to become greater than existing functions. Enhanced areas will have additional opportunities to increase water quality and hydrologic functions to aid in reducing pollutants prior to entering Snoqualmie River, as well as reducing flooding events and increase natural screening of water pollutants and sediments. Planting the tree and shrub vegetation will increase native tree and shrub cover within the project area. MAINTENANCE, MONITORING AND CONTINGENCY The mitigation area will be maintained and monitored in accordance with recommendations outlined in the SMC, which states that monitoring programs will last a minimum of five years and up to 10 years for forested and scrub/shrub wetland communities. We propose to monitor the mitigation site for a period of five years since it is a small area, it is a portion of the buffer that is currently dominated by Himalayan blackberry, which is easily controlled and will be replanted with tree and shrub species. A contingency plan will be implemented if performance standards are not met in the buffer enhancement area. Maintenance Proper maintenance of the planted areas is crucial to plant survival. Maintenance will be conducted throughout the monitoring period. Typical maintenance activities will include: Hand water plants if plants are becoming drought stressed; Re-mulching as needed to control competition from non-native invasive species; Removal of trash, litter and other debris that may accumulate; and Removal of Himalayan blackberry from around newly installed plants, if the invasive species are affecting plant survival. To ensure success of the installed vegetation, non-native invasive species may need to be maintained by hand or mechanical removal as needed. Only desirable native volunteer species in addition to those planted will be encouraged to grow. February 23, 2016 Page 7 File No

12 Monitoring Plan Monitoring will occur for five years after the planting has been completed and an as-built record prepared. Reports will be prepared following Years 1, 2, 3 and 5. If the site is successful (meeting performance standards) a release letter will be requested from the appropriate jurisdiction. The reports will be prepared at the end of each year and document findings from the previous years site visits. Observations to be recorded during each monitoring event include plant survival and growth rates and wildlife occurrences. Photographs will also be taken at each monitoring event to document the evolution of the site over the monitoring period. Monitoring reports with a photographic log will be submitted by the end of the year. The reports will describe the condition of the mitigation area. Maintenance requirements such as trash removal, vandalism, invasive species removal and watering of plants will also be noted in the monitoring report. All planted species will have a minimum of 80 percent survival throughout the monitoring period. Survival of the plantings will be determined by counting and documenting the numbers of dead versus live plants. Species, quantities, general conditions and sizes of enhancement plants will be described and recorded. If the project fails to meet the standards discussed below, implementation of a contingency plan will be required. Performance Standards Performance standards provide benchmarks against which the success of the mitigation plan may be evaluated. Performance standards will be evaluated during each monitoring event through the collection of quantitative data as described above. Failure to meet the performance standards will trigger immediate corrective action. The performance standards discussed below have been developed from the constraints listed above in the baseline conditions section of the report. The performance standards are designed to measure key elements of the mitigation plan that have been designed to improve water quality and habitat functions. WATER QUALITY FUNCTIONS Numerous studies show that sediment and pollutants can be filtered out more quickly in areas containing dense herbaceous vegetation than in areas that lack a dense herbaceous vegetation community (Sheldon et al., 2005 and Castelle et al., 1992). Slopes less than 5 percent were the most successful in removing sediment from water. Therefore, the water quality function performance standard includes: Acceptable cover for native emergent (volunteers), shrub (installed and volunteer) and tree (installed and volunteer) species within each monitoring station will be a minimum of 20 percent during Year 1 and show distinct increases during each subsequent year. HABITAT FUNCTIONS Dense shrub and forested vegetation communities within areas connected to undisturbed wetland or upland habitat are considered to have a relatively high quality habitat value (Sheldon et al., 2005 and Castelle et al., 1992). Although there is a potential to increase richness of wildlife, a performance standard will not be established for wildlife. Therefore, performance standards relating to habitat functions will focus on the installed plantings. These performance standards include: There shall be a minimum of 80 percent survival of all planted species throughout the monitoring period. Survival will be determined by counting and documenting the numbers of dead versus live February 23, 2016 Page 8 File No

13 plants within each monitoring station. Volunteer recruits into a monitoring station may be counted toward offsetting dead planted individuals. In addition to this habitat function performance standard, observations will be made and recorded for wildlife use. As-Built Design Report The first step in implementing an effective monitoring regime is to document initial site conditions in an as-built report. This report will be prepared after planting of the mitigation areas is complete. The report will include the following information: Responsible parties (designer, construction contractors, planting contractor, qualified wetland scientist); Construction timeline (including completion date); Plant numbers and condition at established monitoring stations; Changes to the original plan; Problems encountered during construction and corrective measures taken; and Follow-up actions required (e.g., maintenance), if any, including a schedule and the responsible party that will complete these actions. Monitoring Stations Permanent monitoring stations will be established within the buffer during the as-built monitoring event. The number of monitoring stations, as well as location and extent of each station, will be determined by the monitoring biologist during preparation of the as-built documentation. The monitoring stations should be representative of typical conditions within the mitigation area. The location of each station will be marked with a durable stake or metal post. The permanent stations will be numbered to facilitate consistent documentation between subsequent monitoring events. Data Collection Data collection will be focused on recording plant survival and growth. Wildlife occurrences will also be noted at each of these stations throughout the monitoring period because a goal is to create habitat valuable to a variety of wildlife species. Specifically, the following information will be collected and recorded: Photographs. Photographs will be taken in each of the four cardinal directions from the center of the plot. Plant Survival Ratios. Counts of both dead and live plants will be conducted for each species. The general condition of plants, such as observations of new growth and signs of stress or disease, will also be noted. Plant Cover. Percent cover of each species, including both desirable and invasive, will be estimated. Wildlife. Recordings of wildlife observations will be made as general notes by the monitoring biologist during monitoring events. Performance standards have not been established for wildlife. Observations may include sighting of individual species, nests, burrows, droppings or other indicators. The results will be recorded and included in the monitoring report. February 23, 2016 Page 9 File No

14 Maintenance Requirements. The need for invasive species control, trash removal, watering or vegetation trimming will be noted and included in the monitoring report. Monitoring Reports and Schedule Monitoring will occur for a minimum of five years (Years 1, 2, 3 and 5). The first observation event will occur in the fall following the completion of the vegetation installation. Subsequent monitoring events will occur as listed above in the monitoring plan section. Monitoring reports will be submitted annually and each monitoring event will be documented in a monitoring report that summarizes the condition of the mitigation area with respect to the performance standards identified above. Monitoring reports will be submitted to PSE to distribute as needed. The reports should contain the following elements: Project information (project name and location, name and address of responsible party, any applicable project permit numbers, date project was constructed); Mitigation site information (location of the mitigation site, size and type(s) of habitats included in the mitigation plan, date mitigation site construction was completed); A description of monitoring requirements (name and address of party conducting the monitoring, map of the mitigation site including locations of monitoring stations, dates of previous monitoring events, date of the current or most recent monitoring event); A brief summary of previous monitoring results, maintenance performed and contingency actions undertaken at the mitigation site, including a description of any significant events that occurred on the site that may affect ultimate mitigation success; A list of performance standards; Data from the current monitoring event; A description of whether performance standards were met based on analysis of data collected during the current monitoring event; and Photographs of the site taken from each monitoring station during the most recent monitoring event. Contingency Plan If the planted areas fail to meet the standards discussed above, implementation of a contingency plan will be required. The proposed efforts can fail if certain unfavorable factors occur. Human activity, fire, erosion, invasive plant species, settling and disease may have a negative effect on newly planted vegetation. Plants obtained for this project may be diseased or become diseased over time and result in poor survival rates. Monitoring notes should include observations regarding these and other possible problems that may occur over the monitoring period. As problems are recorded, suggestions and possible solutions should be forwarded to the appropriate staff at the appropriate jurisdictional agency as a component of the monitoring reports. If more than 20 percent mortality of plantings occurs within any of the monitoring years, the mitigation plan will be re-evaluated. If alternative plant species are needed to improve survival, the selection of alternative species will be made by the monitoring biologist and approved by PSE and the local regulatory agency. Contingency measures could include but are not limited to: February 23, 2016 Page 10 File No

15 The plants will be hand watered as needed to offset drought stress on installed plants. Grasses will be mowed or trimmed around installed plants if the grasses are outcompeting and stressing native plants. The mitigation area will be over-planted with appropriate tree species, such as willow, if the installed tree species do not survive. Photographic records and monitoring data will be used to identify the need for contingency plan activation. The success of the plan is dependent upon enhancement proposed for the buffers with the component characteristics described in this report. The applicant is responsible for all costs associated with the contingency plan or corrective actions including materials and labor for replanting and maintenance. CONCLUSIONS GeoEngineers performed wetland and stream evaluation services to provide baseline information within the project area. No wetlands were identified on, or adjacent to, the project site. The Snoqualmie River was identified during the field investigation. The Snoqualmie River is a Class 1 shoreline of the state waterbody and will have a 100-foot buffer according to SMC (D). Approximately 75 square feet of disturbed buffer habitat will be impacted as a result of the proposed project. This impact will be mitigated with approximately 1,500 square feet of invasive species removal and replanting with native tree and shrub species. Appropriate TESC BMP s and construction measures will be implemented and maintained throughout construction to minimize/prevent direct impacts to the river and associated buffer. LIMITATIONS GeoEngineers has prepared this Critical Areas Evaluation Report in general accordance with the scope and limitations of our proposal. Within the limitations of scope, schedule and budget, our services have been executed in accordance with the generally accepted practices for wetland delineation in this area at the time this report was prepared. No warranty or other conditions, express or implied, should be understood. This report has been prepared for the exclusive use of Puget Sound Energy, authorized agents and regulatory agencies following the described methods and information available at the time of the work. No other party may rely on the product of our services unless we agree in advance to such reliance in writing. The information contained herein should not be applied for any purpose or project except the one originally contemplated. The applicant is advised to contact all appropriate regulatory agencies (local, state and federal) prior to design or construction of any development to obtain necessary permits and approvals. February 23, 2016 Page 11 File No

16 REFERENCES Cowardin, L.M., V. Carter, F.C. Golet, and E.T. LaRoe Classification of Wetland and Deep Water Habitats of the United States. Performed for Office of Biological Services, Fish and Wildlife Service, U.S. Department of the Interior, Washington, D.C. Environmental Laboratory U.S. Army Corps of Engineers Wetlands Delineation Manual, Technical Report Y-87-1, U.S. Army Engineer Waterways Experiment Station, Vicksburg, Massachusetts. King County IMAP. Available at: Riley, Don T Ordinary High Water Mark Identification. United States Army Corps of Engineers (USACE), Regulatory Guidance Letter, No ). United States Army Corp of Engineers (USACE) Western Mountains, Valleys, and Coast 2013 Regional Wetland Plant List, US Army Corps of Engineers, Cold Regions Research and Engineering Laboratory. Available at: C_2013v1.pdf. United States Army Corps of Engineers (USACE) Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region, ed. J.S. Wakeley, R. W. Lichvar, and C.V. Noble. ERDC/EL TR Vicksburg, MS: U.S. Army Engineer Research and Development Center. United States Department of Agriculture National Resource Conservation Service (USDA-NRCS) National Hydric Soils List by State. United States Department of Agriculture National Resource Conservation Service (USDA-NRCS) Web Soil Survey. Available at: United States Fish and Wildlife Service (USFWS) Wetlands Mapper. Available at: Washington State Administrative Code WAC Definitions. Available at: Washington State Administrative Code WAC Water Typing System. Available at: Washington State Administrative Code WAC Interim Water Typing System. Available at: Washington State Department of Ecology (Ecology) Washington State Wetlands Identification and Delineation Manual. Publication No Washington State Department of Fish and Wildlife (WDFW) Priority Habitats and Species (PHS) on the Web. Available at: February 23, 2016 Page 12 File No

17 Washington State Department of Natural Resources (DNR) Forest Practices Application Review System (FPARS) Mapping Application. Available at: Type&extent= , , , February 23, 2016 Page 13 File No

18 P:\0\ \GIS\MXDs\ _F01_VicinityMap.mxd Date Exported: 02/22/16 by cchelf SITE 2,000 µ 0 2,000 Feet Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: Mapbox Open Street Map, 2016 Projection: NAD 1983 UTM Zone 10N Vicinity Map Snoqualmie Switch Station Improvements Snoqualmie, Washington Figure 1

19 SE Snoqualmie Switch Station P:\0\ \GIS\MXDs\ _F02_OWHMandBufferLocation.mxd Date Exported: 02/22/16 by cchelf C ity Sno q ua lmie Rd Approximate Pipe Location PSE Mainten an Sn o q u a Fa ll ce Road l mie R iv er Notes: 1. The locations of all features shown are approximate. 2. This drawing is for information purposes. It is intended to assist in showing features discussed in an attached document. GeoEngineers, Inc. cannot guarantee the accuracy and content of electronic files. The master file is stored by GeoEngineers, Inc. and will serve as the official record of this communication. Data Source: King County Aerial 2013 Projection: NAD 1983 HARN StatePlane Washington South FIPS 4602 Feet Legend Approximate OHWM 100 Foot Buffer 50 µ 0 Feet OHWM and Buffer Location 50 Snoqualmie Switch Station Improvements Snoqualmie, Washington Figure 2

20 APPENDIX A Site Photographs

21 Photograph 1. Looking towards the south and the Snoqualmie River from the east end of the switch station. Photograph 2. Looking northeast at the slope where the pipe will be installed. Dominant vegetation consists of Himalayan blackberry. This area is located within the Snoqualmie River buffer Date Exported: 02/23/16 Site Photographs Snoqualmie Switch Station Improvements Snoqualmie, Washington Appendix A

22 Photograph 3. Looking northwest. The switch station and project area are on the right side of the photograph and the Snoqualmie River is on the left side. The paved roadway is used for maintenance of the Snoqualmie Falls PSE facility. Photograph 4. Looking north from the bank of the Snoqualmie River. OHWM indicators include bank erosion (towards the bottom of the photo). The topography slopes up towards the road and switch station (towards the top of the photo) Date Exported: 02/23/16 Site Photographs Snoqualmie Switch Station Improvements Snoqualmie, Washington Appendix A

23 Photograph 5. Looking towards the west and towards the falls from the bank of the Snoqualmie River. Photograph 6. Looking south across the Snoqualmie River towards the southern bank Date Exported: 02/23/16 Site Photographs Snoqualmie Switch Station Improvements Snoqualmie, Washington Appendix A

24 Photograph 7. Looking southeast at the existing outfall to the Snoqualmie River. Photograph 8. The outfall discharges to the Snoqualmie River in this area. This is looking down the slope from the outfall Date Exported: 02/23/16 Site Photographs Snoqualmie Switch Station Improvements Snoqualmie, Washington Appendix A

25 APPENDIX B Mapped Data

26 Feb 11, 2016 User Remarks: This map is for general reference only. The US Fish and Wildlife Service is not responsible for the accuracy or currentness of the base data shown on this map. All wetlands related data should be used in accordance with the layer metadata found on the Wetlands Mapper web site.

27 121 50' 16'' W Soil Map Snoqualmie Pass Area, Washington (Parts of King and Pierce Counties) ' 58'' W 47 32' 35'' N 47 32' 19'' N ' 35'' N 47 32' 19'' N ' 16'' W N Map Scale: 1:2,410 if printed on A portrait (8.5" x 11") sheet. Meters Feet Map projection: Web Mercator Corner coordinates: WGS84 Edge tics: UTM Zone 10N WGS ' 58'' W Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/11/2016 Page 1 of 3

28 Soil Map Snoqualmie Pass Area, Washington (Parts of King and Pierce Counties) MAP LEGEND MAP INFORMATION Area of Interest (AOI) Area of Interest (AOI) Soils Soil Map Unit Polygons Soil Map Unit Lines Soil Map Unit Points Special Point Features Blowout Borrow Pit Clay Spot Closed Depression Gravel Pit Gravelly Spot Landfill Lava Flow Marsh or swamp Mine or Quarry Miscellaneous Water Perennial Water Rock Outcrop Saline Spot Sandy Spot Severely Eroded Spot Sinkhole Slide or Slip Sodic Spot Spoil Area Stony Spot Very Stony Spot Wet Spot Other Special Line Features Water Features Streams and Canals Transportation Rails Interstate Highways US Routes Major Roads Local Roads Background Aerial Photography The soil surveys that comprise your AOI were mapped at 1:24,000. Warning: Soil Map may not be valid at this scale. Enlargement of maps beyond the scale of mapping can cause misunderstanding of the detail of mapping and accuracy of soil line placement. The maps do not show the small areas of contrasting soils that could have been shown at a more detailed scale. Please rely on the bar scale on each map sheet for map measurements. Source of Map: Natural Resources Conservation Service Web Soil Survey URL: Coordinate System: Web Mercator (EPSG:3857) Maps from the Web Soil Survey are based on the Web Mercator projection, which preserves direction and shape but distorts distance and area. A projection that preserves area, such as the Albers equal-area conic projection, should be used if more accurate calculations of distance or area are required. This product is generated from the USDA-NRCS certified data as of the version date(s) listed below. Soil Survey Area: Snoqualmie Pass Area, Washington (Parts of King and Pierce Counties) Survey Area Data: Version 14, Sep 14, 2015 Soil map units are labeled (as space allows) for map scales 1:50,000 or larger. Date(s) aerial images were photographed: Jul 25, 2010 Aug 19, 2010 The orthophoto or other base map on which the soil lines were compiled and digitized probably differs from the background imagery displayed on these maps. As a result, some minor shifting of map unit boundaries may be evident. Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/11/2016 Page 2 of 3

29 Soil Map Snoqualmie Pass Area, Washington (Parts of King and Pierce Counties) Map Unit Legend Snoqualmie Pass Area, Washington (Parts of King and Pierce Counties) (WA634) Map Unit Symbol Map Unit Name Acres in AOI Percent of AOI 10 Barneston gravelly ashy coarse sandy loam, 0 to 8 percent slopes 163 Ogarty gravelly loam, 30 to 65 percent slopes 255 Tokul gravelly medial loam, 8 to 15 percent slopes 258 Tokul-Pastik complex, 45 to 90 percent slopes % % % % 285 Water % Totals for Area of Interest % Natural Resources Conservation Service Web Soil Survey National Cooperative Soil Survey 2/11/2016 Page 3 of 3

30 APPENDIX C Landscape Plan

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