I-90 Snoqualmie Pass East Project (Rocky Run Creek) Mitigation Site USACE IP NWS

Transcription

1 I-90 Snoqualmie Pass East Project (Rocky Run Creek) Mitigation Site USACE IP NWS South Central Region 2016 MONITORING REPORT Wetlands Program Issued March 2017 Environmental Services Office

2 Author: Jennie Husby Editor: Doug Littauer Contributors: Tom Mohagen For additional information about this report or the WSDOT Wetlands Program, please contact: Doug Littauer, Wetlands Program WSDOT, Environmental Services Office P. O. Box 47332, Olympia, WA Phone: Monitoring reports are published on the web at:

3 I-90 Snoqualmie Pass East Project (Rocky Run Creek) Mitigation Site USACE IP NWS USACE IP Number Mitigation Location General Site Information NWS LLID Number Construction Date 2013 Monitoring Period Year of Monitoring 1 of 10 Adjacent Rocky Run Creek and I-90 near Snoqualmie Pass, Kittitas County Type of Impact Area of Project Impact 1 Type of Mitigation Planned Area of Mitigation 2 Permanent Stream Channel Temporary Stream Channel Permanent Stream Buffer Temporary Stream Buffer 0.26 acre 0.35 acre acres 5.02 acres Stream Channel Restoration Stream Buffer Restoration 0.35 acre 1.46 acres 1 Impact numbers sourced from I-90 Snoqualmie Pass East Final Wetlands and Aquatic Resources Mitigation Plan, January 2011, Exhibit ES-2. Additional impacts from this project are listed in Appendix 3, Table 1 of this report. 2 Mitigation numbers sourced from I-90 Snoqualmie Pass East Final Wetlands and Aquatic Resources Mitigation Plan, January 2011, Exhibit 3-3. Additional mitigation sites and their acreage associated with this project are listed in Appendix 3, Table 2 of this report.

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5 Summary of Monitoring Results and Management Activities (2016) Performance Standards 2016 Results 3 Management Activities Density of three native woody plants per 100ft 2 in stream buffer restoration areas Less than 20% cover non-native invasive species in the stream buffer restoration areas 6.6 plants/100ft 2 (CI 80%= ) None observed Weed control activity occurred on 5/4, 7/27, 9/14, 9/20, 9/26, and 9/28 in Report Introduction This report summarizes first-year (Year-1) monitoring activities at the 090 Rocky Run Creek Mitigation Site. Included are a site description, the performance standards, an explanation of monitoring methods, and an evaluation of site development. Monitoring activities included vegetation surveys and photo-documentation on September 22, Estimated values are presented with their corresponding statistical confidence interval. For example, 6.6 plants/100ft 2 (CI 80% = ) means we are 80% confident that the true density value is between 6.0 and 7.2 plants/100ft Rocky Run Creek Annual Monitoring Report

6 What is the 090 Rocky Run Creek Mitigation Site? This is stream mitigation site includes 0.35 acre of restored stream channel and 2.0 acres of restored stream buffer (does not include areas under the bridges) adjacent to I-90 at the Rocky Run Creek crossing. This site was created to mitigate for stream channel and buffer impacts due to culvert removal and bridge construction between MP 56.7 and 56.9 on I-90. The restoration areas are designed to improve fish passage and wildlife habitat connectivity. Figure 1 Site Sketch Appendix 2 includes site directions. 090 Rocky Run Creek Annual Monitoring Report

7 What are the performance standards for this site? Year 1 Performance Standard 1 Native woody vegetation will maintain an average density of three plants per 100 square feet in stream buffer restoration areas. Include native woody colonizing vegetation in this density calculation. Performance Standard 2 Non-native invasive species (Exhibit 5-2 [Appendix 3, Table 3 in this report]) will be controlled throughout all years, allowing native planted and naturally-recruited, desirable plants to establish and survive. There will be no more than 20 percent cover by non-native species throughout the stream buffer restoration areas. Appendix 1 shows the As-Built (WSDOT 2016). 090 Rocky Run Creek Annual Monitoring Report

8 How were the performance standards evaluated? The tables below document the sampling methodology utilized for all of the performance standards (PS) as required by the mitigation plan. For additional details on the methods see the WSDOT Wetland Mitigation Site Monitoring Methods Paper (WSDOT 2008). Placement of Baseline: Parallel to I-90 along the top of the slope of the western most planting area. Length 229m Transects 1-15 PS 1 PS 2 Attribute Density Cover Target population Native Woody Invasive Species Zone Stream Buffer Restoration Stream Buffer Restoration Sample method UBT Qualitative SU width 1 m Total # of SU 15 Baseline Transect Figure 2 Site Sampling Design (2016) 090 Rocky Run Creek Annual Monitoring Report

9 How is the site developing? This site is developing well. Density of native woody vegetation is high and the plantings are becoming established. Cover of invasive species is very low. A deer carcass was observed on site at the time of monitoring, and wildlife cameras captured pictures of a coyote, a bobcat, and deer using the crossing. 090 Rocky Run Creek Annual Monitoring Report

10 Results for Performance Standard 1 (Density of three native woody plants/100ft 2 in the buffer restoration areas): Density of native woody vegetation is estimated at 6.6 plants/100ft 2 (CI80%= ) (Photo 1). This is above the performance standard target. Dominant species include vine maple (Acer circinatum), red elderberry (Sambucus racemosa), and oceanspray (Holodiscus discolor). Results for Performance Standard 2 (Less than 20% cover invasive species in the buffer restoration areas): None observed. Photo 1 Density of native woody plants (September 2016) What is planned for this site? Routine weed control will continue in Rocky Run Creek Annual Monitoring Report

11 Appendix 1 As-Built with Photo Point Locations (from WSDOT 2016) Rocky Run Creek Annual Monitoring Report

12 Appendix 2 Photo Points The photographs below were taken from permanent photo-points on September 22, 2016 and document current site development. Photo Point 1 Photo Point 2 Photo Point 3 Photo Point Rocky Run Creek Annual Monitoring Report

13 Driving Directions: From I-90, take Exit 54 toward Hyak/Gold Creek. Continue on WA-906. Drive to National Forest Development Road 906. Turn right onto WA-906. Turn left to stay on WA-906. Turn right onto National Forest Development Road Rocky Run Creek Annual Monitoring Report

14 Appendix 3 Data Tables Table 1. Phase 1 Summary of Impacts (from Exhibit ES-2 in WSDOT 2011) Resource Permanent Impacts (acres) Temporary Impacts (acres) Wetland Streams Other Waters Buffers Potentially Juristictional Ditches 3,810 linear feet 71 linear feet 090 Rocky Run Creek Annual Monitoring Report

15 Table 2. Credit Summary by Mitigation Site (acres) (From Exhibit 3-3 in WSDOT 2011) Wetland/Riparian Preservation 1 Upland Preservation 1 Wetland Creation Wetland Reestablishment Stream Buffer Restoration 2 Stream Restoration Total Creation Credit Year Constructed Mitigation Site name Upper Gold Creek Preservation Upper Keechelus Lake Gold Creek Wetland Keechelus lake Rocky Run Creek Resort Creek Townsend Creek Wetland Sunset Highway Wetland Total Use of preservation credits are not calculated until applied as mitigation. 2 3:1 credit ratio for buffer restoration 3 5:1 credit ratio for wetland re-establishment within the Keechelus Lake Wetland Site. 4 2:1 credit ratio for the wetland re-establishment within the abandoned Resort Creek Channel Rocky Run Creek Annual Monitoring Report

16 Table 3. Non-native invasive species (Exhibit 5-2 in WSDOT 2011) Scientific Name Acroptilon repens Artemisia absinthium Centaurea diffusa Centaurea pratensis Centaurea stoebe Chondrilla juncea Cirsium arvense Cirsium vulgare Clematis vitalba Cytisus scoparius Geranium robertianum Hedera helix Hieracium aurantiacum Hieracium species Hypericum perforatum Ilex aquifolium Iris pseudacorus Leucanthemum vulgare Linaria dalmatica Lythrum salicaria Polygonum bohemicum, P. cuspidatum, P. sachalinense Potentilla recta Rubus armeniacus (discolor) Rubus laciniatus Solanum dulcamara Tanacetum vulgare Common Name Russian knapweed Absinth wormwood Diffuse knapweed Meadow knapweed Spotted knapweed Rush skeletonweed Canada thistle Bull thistle Field bindweed Scot s broom Herb Robert English Ivy Orange hawkweed Yellow hawkweeds Common St. John s wort English Holly Yellow flag iris Ox-eye daisy Dalmatian toadflax Purple loosestrife Knotweeds (Bohemian, Japanese, and giant) Sulfur cinquefoil Himalayan or Armenian blackberry Evergreen blackberry Bitter nightshade Common tansy 090 Rocky Run Creek Annual Monitoring Report

17 Literature Cited 1. [USACE] US Army Corps of Engineers Department of the Army Individual Permit Number NWS [USACE] US Army Corps of Engineers Department of the Army Individual Permit Modification 2 Number NWS [USACE] US Army Corps of Engineers Department of the Army Individual Permit Modification 3 Number NWS [WSDOT] Washington State Department of Transportation WSDOT Wetland Mitigation Site Monitoring Methods [WSDOT] Washington State Department of Transportation I-90 Snoqualmie Pass East, Final Wetlands and Aquatic Resources Mitigation Plan. Seattle (WA): Washington State Department of Transportation, South Central Region. 6. [WSDOT] Washington State Department of Transportation I-90 Snoqualmie Pass East, Final Wetlands and Aquatic Resources Mitigation Plan Addendum. Seattle (WA): Washington State Department of Transportation, South Central Region. 7. [WSDOT] Washington State Department of Transportation I-90 Snoqualmie Pass East Project, Rocky Run Creek Mitigation Site As-built Planting Plan. 090 Rocky Run Creek Annual Monitoring Report