Wetland and Stream Sensitive Areas Study Boundary Line Adjustment/Reasonable Use Parcels and -0178, Lake Forest Park, WA

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1 March 10, 2017 Darin Seader 2301 NE Perkins Way Lake Forest Park, WA AOA-4800 SUBJECT: Wetland and Stream Sensitive Areas Study Boundary Line Adjustment/Reasonable Use Parcels and -0178, Lake Forest Park, WA Dear Darin: On March 31, 2015, I conducted a sensitive areas reconnaissance and delineation on the subject parcels utilizing the methodology outlined in the Washington State Wetland Identification and Delineation Manual and the May 2010 Regional Supplement to the Corps of Engineers Wetland Delineation Manual: Western Mountains, Valleys, and Coast Region (Version 2.0). Parcel is currently developed with your existing residence and associated yard. Access to the house is from NE Perkins Way. Parcel is undeveloped and forested. 1.0 EXISTING SENSITIVE AREAS Two streams (Whisper Creek and Sarah s Creek) and two wetlands (Wetlands A and B) were identified on or immediately adjacent to the property. The ordinary high water of the streams and the boundary of the wetlands was delineated during the field review and all on-site critical areas were subsequently surveyed (Figure 1). Each of the sensitive areas is described below. 1.1 Whisper Creek Whisper Creek flows from west to east through the northern portion of Parcel and is piped through a culvert under the driveway to the existing residence. The stream then flows from northwest to southeast through a small ravine near the eastern boundary of Parcel

2 Darin Seader March 10, 2017 Page 2 The riparian corridor associated with Whisper Creek on Parcel consists primarily of the existing residence, parking area, driveway, and yard, but also includes scattered trees along the stream banks (see tree survey). The riparian corridor associated with Whisper Creek on Parcel consists of a mature conifer forest dominated by Douglas fir (Pseudotsuga menziesii), western red cedar (Thuja plicata), Oregongrape (Mahonia nervosa), Indian plum (Oemleria cerasiformis), sword fern (Polystichum munitum), and English ivy (Hedera helix). Whisper Creek is considered a Type 1 stream by the City of Lake Forest Park and requires a standard 115-foot buffer plus 15-foot building setback per LFPMC A. 1.2 Sarah s Creek Sarah s Creek flows from west to east through the southern portion of the site and is a tributary to Whisper Creek. The riparian corridor of Sarah s Creek includes Wetlands A and B as well as a mixed upland forest containing Douglas fir, western red cedar, red alder (Alnus rubra), big-leaf maple (Acer macrophyllum), Indian plum, salmonberry (Rubus spectabilis), hazelnut (Corylus cornuta), red elderberry (Sambucus racemosa), sword fern, and English ivy. The eastern portion of Sarah s Creek (below OHW 2-9) was relatively flat and was considered a Type 1 stream that requires a standard 115-foot buffer plus 15-foot building setback. The stream above OHW 2-9 was much narrower and on a steeper grade that did not appear to provide salmonid habitat or access. This portion of the stream was considered a Type 2 stream and requires a standard 50-foot buffer plus 15-foot building setback per LFPMC A. Sarah s Creek is not identified on: 1) the Washington Department of Fish and Wildlife s Priority Habitats or Species (PHS) database, 2) WDFW s Salmonscape mapping, or 3) the Department of Natural Resources Forest Practices Application Review System (FPARS) stream mapping. 1.3 Wetland A Wetland A is located in the southern portion of the site and is hydrologically supported by groundwater seepage. This seepage drains north into Sarah s Creek via two small topographic swales. Vegetation within the wetland at the time of the delineation consisted of a scrub-shrub plant community that included salmonberry, skunk cabbage (Lysichiton americanum), climbing nightshade (Solanum dulcamara), field horsetail (Equisetum arvense), stinging nettle (Urtica dioica), and English ivy.

3 Darin Seader March 10, 2017 Page 3 Although the wetland had some canopy coverage, no trees were rooted within the wetland and the wetland was determined to be a Category 3 wetland as defined in LFPMC AA since it: 1) does not meet any of the criteria for Category 1 or 2 wetlands, 2) is less than one acre in size, and 3) contains less than two wetland classes. Category 3 wetlands require a standard 50-foot buffer plus 15-foot building setback per LFPM A. Attachment A contains data sheets prepared for a representative location in both the wetland and upland. These data sheets document the vegetation, soils, and hydrology information that aided in the Wetland A boundary delineation. 1.4 Wetland B Wetland B is located off-site to the southeast and consists of a small groundwater discharge area that drains down to Sarah s Creek. The wetland was similar to Wetland A and at the time of the delineation vegetation consisted of a scrub-shrub plant community that included salmonberry, Indian plum, red elderberry, skunk cabbage, lady fern (Athyrium filix-femina), and English ivy. Wetland B was also determined to be a Category 3 wetland since it: 1) does not meet any of the criteria for Category 1 or 2 wetlands, 2) is less than one acre in size, and 3) contains less than two wetland classes. Wetland B would also require a standard 50-foot buffer plus 15-foot building. 2.0 PROPOSED PROJECT The proposal consists of a lot-line adjustment to allow for development of a new single-family residence in the far southeastern portion of the site using the Reasonable Economic Use Exception Process. The goal of the lot-line adjustment is to preserve the mature trees on vacant Parcel and locate the reasonable use lot in a more degraded portion of Parcel to allow for a small single-family residence. Since Parcel consists of a highvalue mature coniferous forest that provides significant benefit to both Whisper and Sarah s Creeks, it was determined that utilizing a lot-line adjustment to provide a building site in the far southern portion of Parcel-0181 adjacent an existing access point would be the preferred option. By placing the residence in the far southern portion of the property all direct impacts to sensitive areas would be avoided and no crossings of streams or wetlands would be necessary. Unavoidable impacts would be minimized by keeping the residence and associated required maintenance area around the house small. All unavoidable impacts would be mitigated through the implementation of a sensitive area enhancement plan and would therefore meet the mitigation sequencing required as part of LFPMC

4 Darin Seader March 10, 2017 Page PROPOSED MITIGATION Mitigation for the new residence in the southern portion of the site would occur through the enhancement of the riparian corridor and wetlands throughout the southern portion of the property and additional plantings along the ordinary high water of Whisper Creek. Planting with native vegetation would increase the plant species and structural diversity within the sensitive areas and their buffers, thereby increasing the area s value to wildlife. The planted buffers would also provide increased physical and visual screening to the sensitive areas from the existing and proposed residence. 3.1 Goal, Objectives, and Performance Standards for Enhancement Areas The primary goal of the enhancement plan is to increase the habitat functions of the sensitive areas and their buffers over current conditions. To meet this goal, the following objectives and performance standards have been incorporated into the design of the plan: Objective A: Increase the structural and plant species diversity within the mitigation area. Performance Standard: There will be 100% survival of all woody planted species throughout the mitigation area at the end of the first year of planting. Following each monitoring event after the first year of planting, there will be at least an 80% survival rate of all planted tree and shrub species or equivalent replacement of a combination of planted and re-colonized native species. In addition, following the first year after planting, a combination of native or naturalized woody vegetation will cover at least 15% of the mitigation area. The areal coverage will increase to at least 25% following the second year after planting, 30% following the third year after planting, 40% following the fourth year after planting, and 50% following the fifth year after planting. Objective B: Limit the amount of invasive and exotic species within the mitigation area. Performance Standard: After construction and following every monitoring event for a period of at least 5 years, exotic and invasive plant species will be maintained at levels below 10% total cover in all planted areas. These species include, but are not limited to, Himalayan and evergreen blackberry, reed canarygrass, morning glory, Japanese knotweed, English ivy, thistle, periwinkle, and creeping nightshade. 3.2 Monitoring Methodology The monitoring program will be conducted for a period of at least 5 years, with annual reports submitted to the City of Lake Forest Park. Vegetation sample plots or transects will be established to measure plant survival and areal coverage.

5 Darin Seader March 10, 2017 Page 5 Photo-points will be established from which photographs will be taken throughout the monitoring period. These photographs will document general appearance and progress in plant community establishment in the enhancement area. Review of the photos over time will provide a visual representation of success of the enhancement plan. 3.3 Maintenance Maintenance will be conducted on a routine, year round basis. Remedial action on the site shall be implemented on an as-needed basis at the direction of the consultant or the owner. 3.4 Weed Control Routine removal and control of non-native and other invasive plants (e.g., Himalayan and evergreen blackberry, Japanese knotweed, English ivy, morning glory, thistle and creeping nightshade) shall be performed only by manual means, unless specifically authorized by the consulting biologist. No spraying will be conducted adjacent the stream. Undesirable and weedy exotic plant species shall be maintained at levels below 10% total cover within any given stratum at any time during the five-year monitoring period. 3.5 Contingency Plan All dead plants will be replaced with the same species or an approved substitute species that meets the goal of the enhancement plan. Plant material shall meet the same specifications as originally-installed material. Replanting will not occur until after reason for failure has been identified (e.g., moisture regime, poor plant stock, disease, shade/sun conditions, wildlife damage, etc.). Replanting shall be completed under the direction of the consultant, City of Lake Forest Park, or the owner. 3.6 As-Built Plan Following installation of the plant material, an as-built plan for the enhancement area will be provided to the City of Lake Forest Park. The as-built plan will identify and describe any changes in relation to the original approved plan and will provide a baseline for subsequent monitoring of the site to ensure compliance with the plan during the monitoring period.

6 Darin Seader March 10, 2017 Page 6 If you have any questions, please let me know. Sincerely, ALTMANN OLIVER ASSOCIATES, LLC John Altmann Ecologist

7 Seader Property The information included on this map has been compiled by King County staff from a variety of sources and is subject to change without notice. King County makes no representations or warranties, express or implied, as to accuracy, completeness, timeliness, or rights to the use of such information. This document is not intended for use as a survey product. King County shall not be liable for any general, special, indirect, incidental, or consequential damages including, but not limited to, lost revenues or lost profits resulting from the use or misuse of the information contained on this map. Any sale of this map or information on this map is prohibited except by written permission of King County. Date: 1/27/2017 Notes: King County, Pictometry International Corp ±

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