I-405 Congestion Relief and Bus Rapid Transit Projects: Renton Nickel Improvement Project (Renton Stage 1) Mitigation Site USACE NWP

Transcription

1 I-405 Congestion Relief and Bus Rapid Transit Projects: Renton Nickel Improvement Project (Renton Stage 1) Mitigation Site USACE NWP Northwest Region 2016 MONITORING REPORT Wetlands Program Issued March 2017 Environmental Services Office

2 Author: Tom Mohagen Editor: Doug Littauer Contributors: Jennie Husby 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-405 Congestion Relief and Bus Rapid Transit Projects: Renton Nickel Improvement Project (Renton Stage 1) Mitigation Site USACE NWP (23) General Site Information USACE Permit Number Mitigation Location LLID Number Construction Date Monitoring Period Year of Monitoring 7 of 10 Type of Impact Area of Project Impact 1 Type of Mitigation Planned Area of Mitigation 2 Multiple locations within the cities of Renton and Tukwila Wetland Buffer Stream Channel Impacts Stream Shading Impacts 1.61 acre 4.96 acre 0.07 acre 0.27 acre Urban Forest Planting 1.7 acre 0.24 acre Understory Planting 1 Impact numbers sourced from (USACE 2006). 2 Mitigation numbers sourced from (USACE 2006). The 1.61 acres of wetland impact are being mitigated for with credits from the Springbrook Creek Wetland and Habitat Mitigation Bank. The actual urban forest planting (2.22 acres) and understory planting areas (0.59) are higher than the USACE required acres in the table.

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5 Summary of Monitoring Results and Management Activities (2016) Performance Standards (Springbrook Stream Mitigation Site) Performance Criteria Results 4 Establish 160 linear feet of new channel, where the existing box culvert is located, with three boulder groups Establish 290 linear feet of off-channel habitat in side channel with 14 pieces of LWD The bankfull width/depth and wetted width/depth ratio will be maintained within 80 percent of the reference reach data Performance Standards and Permit Requirements (All Mitigation Areas) After five years, aerial cover of native woody species will be at least 60% in riparian planting areas At least two native, non-invasive riparian species will achieve a minimum of 10% relative cover for each species in the riparian planting area Reed canarygrass (Phalaris arundinacea), purple loosestrife (Lythrum salicaria), Scotch broom (Cytisus scoparius), and Japanese knotweed (Reynoutria japonica) will not exceed 20% aerial cover Japanese Knotweed will not be present Present according to construction plans 15 root-wads and six rock features present Not evaluated West Fork Panther Creek- 95% cover Green River- 79% cover (CI80% = 70-88%) Gilliam Creek- 42% cover (CI80% = 31-52%) Springbrook Creek- 80% cover A minimum of two native species have achieved ten percent relative cover in the riparian planting areas at all four sites. Qualitatively estimated: West Fork Panther Creek- 3% cover Green River- 3% cover Gilliam Creek- 3% cover Springbrook Creek- 1% cover West Fork Panther Creek- Absent Green River- Absent Gilliam Creek- Absent Springbrook Creek- Present 3 Performance Standards apply to Springbrook Creek stream mitigation site, USACE permit requirements apply to both Springbrook Creek stream mitigation site as well as 2.22 acres of urban forest riparian plantings and 0.59 acres of understory plantings located on Gilliam Creek, West Fork Panther Creek, and the Green River. 4 Estimated values are presented with their corresponding statistical confidence interval. For example, 79% cover (CI80% = 70-88%) means we are 80% confident that the true woody cover value is between 70 and 88 percent. 405 Renton Stage Annual Monitoring Report

6 Report Introduction This report summarizes Year-7 monitoring activities at the 405 Renton Stage 1 Mitigation Sites. Included are site descriptions, the performance standards, an explanation of monitoring methods, and an evaluation of site development. Monitoring activities included vegetation surveys, and photo-documentation that took place on September 8 and October 4, Renton Stage Annual Monitoring Report

7 What are the 405 Renton Stage 1 Stream Mitigation Sites? The Springbrook Creek (Figure 1) site consists of a created stream bed of 160 linear feet and 9,000 square feet in the former location of a box culvert. This site was created to compensate for impacts to stream channel, shading, and stream buffer due to road improvements along I-405 and SR 167. The created side channel and enhanced riparian plantings are designed to provide habitat improvement opportunities of increased of riparian diversity of trees and shrubs, create high quality pools in the side channel, increase potential for year-round off-channel rearing, and provide large woody debris revetment along the side channel. An additional 2.22 acres of urban forest riparian plantings and 0.59 acre of understory plantings are located on Gilliam Creek, West Fork Panther Creek, and the Green River. Appendix 1 includes site directions. Figure 1 Site Sketch 405 Renton Stage Annual Monitoring Report

8 What are the performance criteria for this site? Year 5 Performance Standard 1 (Springbrook Creek) Establish 160 linear feet of new channel, where the existing box culvert is located, with three boulder groups. Performance Standard 2 (Springbrook Creek) Establish 290 linear feet of off-channel habitat in side channel with 14 pieces of LWD. Performance Standard 3 (Springbrook Creek) The bankfull width/depth and wetted width/depth ratio will be maintained within 80 percent of the reference reach data. Performance Standard 4 (All mitigation areas) After five years, aerial cover of native woody species will be at least 60 percent in riparian planting areas. Performance Standard 5 (All mitigation areas) At least two native, non-invasive riparian species will achieve a minimum of 10 percent relative cover for each species in the riparian planting area. Year 7 USACE Permit Requirement 1 (All mitigation areas) Reed canarygrass, purple loosestrife, Scot's broom, and Japanese knotweed will not exceed 20 percent aerial cover in the riparian restoration areas. If this cover threshold is exceeded, weed eradication or control measures will be implemented as part of a detailed contingency plan. USACE Permit Requirement 2 (All mitigation areas) Japanese Knotweed shall not be present at the Springbrook Creek stream mitigation site, the 1.7 acres of urban forest riparian planting, and the 0.24 acre Gilliam Creek understory plantings. USACE Permit Requirement 3 (Gilliam Creek and Green River Sites) After seven years, aerial cover of native woody species will be at least 35 percent in the urban forest riparian plantings Appendix 1 shows the planting plan (WSDOT 2008). 405 Renton Stage Annual Monitoring Report

9 How were the performance standards evaluated? Panther and Springbrook Creek have developed more rapidly than anticipated and have been meeting the Year 10, final year standards for woody cover for three years. On April 12, 2016 a request to discontinue quantitative sampling for the riparian woody cover was sent to USACE, this request was accepted on April 13, The final year standards are still currently being met. Performance Standards 1 and 2 were assessed visually and Performance Standard 3 was not assessed due to a lack of reference data. The tables below document the sampling methodology utilized for all of performance standards (PS) and permit requirement (PR) 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). Green River Sample Design: The sample design for the Green River site was similar to the one used at Gilliam Creek (Figure 2), each had a baseline placed parallel to the creek and transects were run perpendicular to the baseline. The baseline was 111m and had 11 transects. Figure 2 (2016) Gilliam Creek Site Sampling Design Gilliam Creek Placement of Baseline: Roughly parallel to Gilliam Creek Segmented Baseline: Length 44m Transects 1-4; Length 120m Transects 5-12 PS 4 & 5 PR 1 & 2 PR 3 Attribute Cover/Relative Presence/Absence Cover & Cover Cover Target population Native Woody Noxious Weeds/ Invasive sp. Native Woody Zone Riparian Riparian Riparian Sample Line Intercept/ Line method Qualitative Qualitative Intercept SU length Variable N/A Variable SU width N/A N/A N/A Points per SU N/A N/A N/A Total # of SU N/A N/A N/A 405 Renton Stage Annual Monitoring Report

10 How are these sites developing? West Fork Panther Creek Panther Creek continues to meet all of the final year performance criteria for the third year in a row. Riparian plantings on the west side of Panther Creek are thriving. There is a thick overstory of conifers and an understory of shrubs. Invasive cover remains low on site. Green River Green River planting area is thickly vegetated with native woody trees and shrubs. This is the second year in a row that Green River has met the final year performance standards, the first year quantitatively. Japanese knotweed has not been observed for the second year in a row and invasive cover remains low. Gilliam Creek Both the understory and the urban forest plantings have developed into a diverse community at Gilliam Creek. Gilliam Creek still struggles to meet the year five woody cover standard of 60 percent, however if the sampling was to include the mature black cottonwood (Populus balsamifera) the cover would greatly exceed the performance standard. Invasive cover is low throughout the site and Japanese knotweed has not been seen along the banks of the creek in two years. Springbrook Creek Mitigation Site Springbrook Creek continues to meet all of the final year performance criteria for the third year in a row, except for the presence of Japanese knotweed on site. Many western red cedar (Thuja plicata) have died off at Springbrook, but not enough to bring the native woody cover down substantially. 405 Renton Stage Annual Monitoring Report

11 Results for Performance Standard 1 (Springbrook Creek) (Establish 160 linear feet of new channel, where the existing box culvert is located, with three boulder groups): At the time of the monitoring visit, the box culvert had been removed and approximately 160 feet of new channel along Springbrook creek was present (Photo 1). The boulder groups were present and the site appears constructed to plan. Results for Performance Standard 2 (Establish 290 linear feet of off-channel habitat in side channel with 14 pieces of LWD): A side channel off Springbrook creek is present and it appeared to be at least 290 feet long. Fifteen pieces of LWD were observed in and along the side-channel and boulders were interspersed with the LWD (Photo 1). Photo 1 Off channel area with LWD (Oct 2016) Results for Performance Standard 3 (The bankfull width/depth and wetted width/depth ratio will be maintained within 80 percent of the reference reach data. A reference reach will be identified and these data will be obtained during the final design of the proposed stream mitigation and proposed bridges): At this time, we do not have access to reference data regarding the bankfull and wetted width/depth ratios for Springbrook creek. 405 Renton Stage Annual Monitoring Report

12 Performance Standard 4 and 5 (All Areas) (After five years, aerial cover of native woody species will be at least 60 percent in riparian planting areas and two woody species will achieve at least 10 percent relative cover): Cover of native woody species at West Fork Panther Creek is 95 percent. The woody community on the west side of Panther creek is thriving, and is dominated by willows (Salix species) and Douglas-fir (Pseudotsuga menziesii). Each species provides at least 10 percent relative cover (Photo 2). Cover of native woody species at the Green River riparian planting area is 79% (CI80%= 70-88%) (Photo 3). Dominant species present include Pacific willow (Salix lasiandra) and Lewis' mock orange (Philadelphus lewisii) both with at least 10 percent relative cover. Photo 2 Woody cover at Panther Creek (August 2016) Cover of native woody species at the Gilliam Creek riparian planting area is 42% (CI80%= 31-52%). Dominant species observed include red alder (Alnus rubra), snowberry (Symphoricarpos albus) and Pacific ninebark (Physocarpus capitatus), each with at least 10 percent relative cover. Cover of native woody species at Springbrook Creek is qualitatively estimated at 80 percent and is dominated by western red cedar (Thuja plicata), Pacific ninebark, and willows, each with at least 10 percent relative cover. Photo 3 Gilliam Creek urban forest (August 2016) 405 Renton Stage Annual Monitoring Report

13 Results for Permit Requirements 1 and 2 (Reed canarygrass, purple loosestrife, Scot's broom, and Japanese knotweed will not exceed 20 percent aerial cover and Japanese knotweed shall not be present): The cover of non-native species is qualitatively estimated to be: West Fork Panther Creek- 3% cover Green River- 5% cover Gilliam Creek- 1% cover Springbrook Creek- 5% cover Japanese knotweed was only present at Springbrook Creek. USACE Permit Requirement 3 (Gilliam Creek and Green River Sites) (After five years, aerial cover of native woody species will be at least 25 percent in the urban forest riparian plantings): Cover of native woody species in the urban forest planting area at Gilliam Creek is 42% (CI80%= 31-52%) (Photo 3). This cover value exceeds the permit requirement target. Cover of native woody species in the urban forest planting area at the Green River site is 79% (CI80%= 70-88%), which also exceeds the permit requirement target. 405 Renton Stage Annual Monitoring Report

14 What is planned for this site? Routine weed control will continue in Renton Stage Annual Monitoring Report

15 Appendix 1 Planting Plan (from WSDOT 2008) Springbrook Creek 405 Renton Stage Annual Monitoring Report

16 (from WSDOT 2008) Panther Creek 405 Renton Stage Annual Monitoring Report

17 (from WSDOT 2008) Panther Creek 405 Renton Stage Annual Monitoring Report

18 (from WSDOT 2008) Gilliam Creek 405 Renton Stage Annual Monitoring Report

19 (from WSDOT 2008) Green River 405 Renton Stage Annual Monitoring Report

20 (from WSDOT 2008) Green River 405 Renton Stage Annual Monitoring Report

21 Driving Directions: Gilliam Creek Plantings Head North on I-5 (50mi). Take Exit 153 for South Center Parkway and Mall. Head north on South Center/Tukwila Parkway. When you reach 61 st Avenue, park at the mall. The only safe parking is in the mall parking lot. You will have to cross the street and walk east to reach the plantings. Green River Plantings (from Gilliam Creek) Continue east on South Center/Tukwila Parkway. Cross under I-405 and head east on (right) Southcenter Boulevard/Fun Center Way. Take a left on Interurban Avenue South. Take the second right on Fort Dent Way, then turn around and get back onto Interurban Avenue southbound. Park on shoulder of Interurban Avenue South, north of I Panther Creek Plantings (from Green River Plantings) Head north on I-405 (~2mi). Take Exit 2 SR-167 South toward Auburn. Take the East Valley Road/Southwest 43 rd exit towards South 180 th Street. Turn right at East Rainier Avenue South/East Valley Road. Park in the back of the Clarion Hotel. The plantings are along the right-of-way of SR-167. Springbrook Creek Plantings (From Panther Creek Plantings) Head north on East Valley Road. Take a left on Southwest 34 th Street. Take a right on Oaksdale Avenue Southwest. The site is located on the corner of 16 th Street Southwest and Oakdale Avenue Southwest. There is a black gate around the site on the north side of 16 th just west of Oaksdale Avenue. Park inside the gate. 405 Renton Stage Annual Monitoring Report

22 Literature Cited 1. [USACE] US Army Corps of Engineers Department of the Army Nationwide Permit Number Washington State Department of Fish and Wildlife Hydraulic Project Approval Permit Number [WSDOT] Washington State Department of Transportation I-405 Congestion Relief and Bus Rapid Transit Projects. Renton Nickel Improvement Project (I-405, I-5 to SR 169). Seattle (WA): Washington State Department of Transportation, Urban Corridors Office. 4. [WSDOT] Washington State Department of Transportation I-405 Congestion Relief and Bus Rapid Transit Projects. Renton Nickel Improvement Project (I-405, I-5 to SR 169). Conceptual Stream Mitigation Plan. Planting Plans. 5. [WSDOT] Washington State Department of Transportation WSDOT Wetland Mitigation Site Monitoring Methods Renton Stage Annual Monitoring Report