I-5/Mellen Street to Blakeslee Junction (Horseshoe Lake) Mitigation Site USACE IP NWS

Transcription

1 I-5/Mellen Street to Blakeslee Junction (Horseshoe Lake) Mitigation Site USACE IP NWS Southwest Region 2018 MONITORING REPORT Wetlands Program Issued March 2019 Environmental Services Office

2 Author: Trace McKellips Editor: Kristen Andrews For additional information about this report or the WSDOT Wetlands Program, please contact: Kristen Andrews, Wetlands Program WSDOT, Environmental Services Office P. O. Box 47332, Olympia, WA Phone: Monitoring reports are published on the web at:

3 I-5/Mellen Street to Blakeslee Junction (Horseshoe Lake) Mitigation Site USACE IP NWS USACE IP Number Mitigation Location General Site Information NWS LLID Number Construction Date Monitoring Period Year of Monitoring 3 of 10 South of the City of Centralia and 0.5 miles west of I-5 in Lewis County Type of Impact Wetland Buffer Oak Woodland Area of Project Impact 1 Type of Mitigation Planned Area of Mitigation acres 2.32 acres Buffer establishment Oak Woodland Establishment 25 acres 12 acres 1 Impact numbers sourced from WSDOT Mitigation numbers sourced from WSDOT 2011.

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5 Summary of Monitoring Results and Management Activities (2018) Performance Standards 2018 Results 3 Management Activities Minimum density of 4,000 plants/acre and at least 6 species of trees and/or shrubs present Blackberry Species and Class B (WA Dept. of Agriculture and Lewis County Weed Board) noxious weeds will not exceed 15% Class A Noxious Weeds (WA Dept. of Agriculture and Lewis County), Japanese knotweed, and purple loosestrife shall be treated 4,967 plants/acre (CI 80% = ) with 20 species present Planted 7,400 native woody plants in January % cover (qualitative) Spot sprayed for blackberry species, tansy ragwort, and non-native thistle species None observed (May-Jun 2018) Report Introduction This report summarizes third-year (Year 3) monitoring activities at the 005 Horseshoe Lake 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 July 16 and 17, Estimated values are presented with their corresponding statistical confidence interval. For example, 4,967 plants/acre (CI 80% = ) means we are 80% confident that the true density is between 4452 and 5482 plants/acre. 005 Horseshoe Lake Annual Monitoring Report

6 What is the 005 Horseshoe Lake Mitigation Site? This acre mitigation site (Figure 1) is a site located directly south of the City of Centralia and west of Interstate 5. This site was created to compensate for the permanent loss of acres of wetland buffer and 2.32 acres of oak woodland due to road improvements along Interstate 5. Twenty-five acres of the site were used for wetland buffer mitigation and 12 acres were used for Oregon white oak woodland mitigation with the remaining acreage to be used to mitigate for future projects. This site is intended to reestablish important buffer functions in a largely fragmented floodplain and enhance valuable wildlife habitat. Figure 1 Site Sketch The 005 Horseshoe Lake mitigation site is located just 1300 feet north of the Chehalis River with a tributary to the river flowing through the site, north to south. Horseshoe Lake is on the eastern boundary of the site and there is a depression in the southeastern corner of the site that impounds water during the winter months. Appendix 2 includes site directions. 005 Horseshoe Lake Annual Monitoring Report

7 What are the performance standards for this site? Year 3 Performance Standard 1 At monitoring Year 3, there will be a minimum density of 4,000 living native woody species per acre and at least six species of native trees and/or shrubs will be present in the native woody species areas (Scrub-shrub, wetland buffer, and riparian enhancement areas). Performance Standard 2 The aerial extent of blackberry species and Class B (WA Dept of Agriculture and Lewis County Weed Board) noxious weeds will not exceed 15 percent in the combined scrub-shrub, buffer, and riparian planting areas, exclusive to each mitigation site. Performance Standard 3 If/when detected, Class A noxious weeds (WA Dept. of Agriculture and Lewis County), Japanese knotweed, and purple loosestrife shall be treated so that the species do not exist on the sites. These species shall not be included in the 15 percent cover allowed for invasive species. Appendix 1 shows the planting plan (WSDOT 2014). 005 Horseshoe Lake Annual Monitoring Report

8 How were the performance standards evaluated? The tables below document the sample methods used for performance standards (PS) as required by the mitigation plan or permits. For additional details on the methods see the WSDOT Wetland Mitigation Site Monitoring Methods Paper (WSDOT 2008). Placement of Baseline: The 752 meter baseline was placed lengthwise across the site at a 20 bearing. Using ESRI software, a random number generator determined the first transect point. An interval of 40 meters separated each remaining transect. Attribute PS 1 PS 2 PS 3 Density Cover Presence/Absence Target Native woody Noxious/ population species invasive Noxious weeds Zone Entire site Entire Site Entire Site Sample method UBT Qualitative Qualitative SU length N/A N/A N/A SU width 1 N/A N/A Points per SU N/A N/A N/A Total # of SU 19 N/A N/A Figure 2 Site Sampling Design (2018) 005 Horseshoe Lake Annual Monitoring Report

9 How is the site developing? Overall the site is developing well. The site meets its third-year native woody density standard. Native woody species are established throughout the site and have an average height of 1-2 meters. The upland oak woodland zone is dominated by snowberry (Symphoricarpos albus). Other prominent upland species are western serviceberry (Amelanchier alnifolia), Oregon ash (Fraxinus latifolia), and Indian plum (Oemleria cerasiformis). Oregon white oaks (Quercus garryana) have also established in the upland. This species provides a unique vegetation community and associated wildlife habitat. Some plants however have not adapted to the hot and dry summer conditions. Over 63,000 native woody species suited to dry summers will be planted in January Plantings in the wetland along the southern and western site edges are dominated by redosier dogwood (Cornus alba) and Oregon ash (Fraxinus latifolia). These established species appear to be preventing the intrusion of reed canarygrass (Phalaris arundinacea) that surround the site perimeter. Isolated thickets of non-native blackberry and patches of tansy ragwort (Jacobaea vulgaris) are found throughout the upland zone. The site s agricultural history and human disturbances have resulted in a host of Class C weeds and other non-native species to establish on site. Most native species are able to coexist alongside these introduced plants. 005 Horseshoe Lake Annual Monitoring Report

10 Results for Performance Standard 1 (Minimum density of 4,000 living woody species per acre and at least six species of native trees and/or shrubs): Density is estimated at 4967 plants/acre (CI80% = ). Snowberry (Symphoricarpos albus) was the dominant species. Other species that were abundant on site included western serviceberry (Amelanchier alnifolia), redosier dogwood (Cornus alba), Oregon ash (Fraxinus latifolia), and Indian plum (Oemleria cerasiformis) (Photo 1). A total of 20 species of trees and shrubs were included in the sample. Results for Performance Standard 2 (Blackberry Species and Class B noxious weeds will not exceed 15 percent): Photo 1 Native plants in Upland Buffer (July 2018) Non-native blackberry species are estimated at 3 percent cover across the site. Tansy ragwort (Jacobaea vulgaris) was also observed throughout the planting areas (Photo 2). Results for Performance Standard 3 (Class A Noxious Weeds (WA Dept. of Agriculture and Lewis County), Japanese knotweed, and purple loosestrife shall be treated): No Class A noxious weeds observed. Photo 2 Tansy Ragwort & Class C weeds (July 2018) 005 Horseshoe Lake Annual Monitoring Report

11 What is planned for this site? WSDOT will continue to control Class B noxious weed species. Over 63,000 bare root plants will be planted in the winter of in northern sections of the site with lower overall cover that had been previously dominated by Queen Ann s Lace. These plants include western serviceberry, redosier dogwood, oceanspray, Indian plum, snowberry, Lewis' mock orange (Philadelphus lewisii), hardhack (Spiraea douglasii), and twinberry honeysuckle (Lonicera involucrata). 005 Horseshoe Lake Annual Monitoring Report

12 Appendix 1 Planting Plan (from WSDOT 2014) 005 Horseshoe Lake Annual Monitoring Report

13 Appendix 2 Photo Points The photographs below were taken from permanent photo-points on July 18, 2018 and document current site development. Photo Point 1A Photo Point 1B Photo Point 1C Photo Point 1D 005 Horseshoe Lake Annual Monitoring Report

14 Photo Point 2A Photo Point 2B Photo Point 3 Photo Point 4A 005 Horseshoe Lake Annual Monitoring Report

15 Photo Point 4B Photo Point 4C Driving Directions: From I-5 take Exit 81. Take ramp right for WA 507, north toward Mellen Street. Turn right onto WA 507/Mellen Street and go forward until bearing left onto Military Road. In a half a mile, turn left onto South Scheuber Road. The gravel driveway to the site will be directly on the east side of the street. Park here and walk into the planted area of the site. 005 Horseshoe Lake Annual Monitoring Report

16 Literature Cited 1. [USACE] US Army Corps of Engineers Department of the Army Individual Permit Number NWS [WDFW] Washington State Department of Fish and Wildlife Hydraulic Project Approval Control Number [WSDOT] Washington State Department of Transportation Final Critical Areas Mitigation Report, I-5/Mellen Street to Blakeslee Junction Add Lanes, Interchange Improvement Project. Lewis County (WA): Washington State Department of Transportation, Southwest Region. 4. [WSDOT] Washington State Department of Transportation I-5 Mellen Street to Blakeslee Junction Stage 2, Horseshoe Lake Planting Plan. 5. [WSDOT] Washington State Department of Transportation WSDOT Wetland Mitigation Site Monitoring Methods Horseshoe Lake Annual Monitoring Report