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Home My WebLink AboutR-417988" APPROXIMATE LOCATION OF TRAIL TO CONNECT TO CITY OF NEWCASTLES TRAIL ALONG NE 43RD ST RIGHT—OF—WAY EX. DITCH APPROXIMATE — WETLAND C BOUNDARY OF CATEGORY IV STREAM S 50' BUFFER WETLAND A INSET 2 SHT 2: TO BE FILLED / J V. / \ 1,585 SF ` _- �� L...... � � 11;,;•"� ill 1 �� Ily (JII !� � �• uuwu ,I� luuun , WETLAND B CATEGORY IV 00 CC��i��< UTILITY EASEMENT--'o"' STEEP 6LUFt AREA 436 SF �J - I�i� r Ali II� I 1 �Illll''��1Ilk �IIII�[q�►, L1 IG _ ��I�`► I I I I I I I I I I I I I I I I I IUNOPENED I RIGHT—OF—WAY OF 112TH AVE SE i i i i I I APPROXIMATE LOCATION OF i I STREAM CROSSING/ i I I ' i i I I ' i i I ' i i i i i i i i STREAM S I TYPE NP 75' BUFFER i i I I - " I 11 I I I I I I I WETLAND D I ATEGORY IV I 50' BUFFER I I I APPROXIMATE LOCATION OF TRAIL IMPACT I _ i -L- POSED TRAIL BUFFER ADDITION SF :FER 1ANCEMENT 6 SF =FER REDUCTION a5 SF =FER IMPACT SF TLAND D BE ENHANCED )0 SF TLAND IMPACT SF =FER IMPACT SF =FER ADDITION 30 SF .0 0 20 40 .0 :0 WETLAND PROPERTY BOUNDARY WETLAND ENHANCEMENT — — RIGHT—OF—WAY STREAM BUFFER AVERAGING APPROX. STREAM (REDUCTION) BOUNDARY BUFFER AVERAGING (ADDITION) ---- STANDARD BUFFER BUFFER IMPACT ............ 75% OF STANDARD BUFFER FINAL BUFFER/PERMANENT WETLAND IMPACT FENCE/SIGNS 15' BUFFER STRUCTURE BUFFER ENHANCEMENT ----- SETBACK STEEP SLOPE AREA 9,997 SF I ` I I I � BUFFER REDUCTION 1,032 SF BUFFER IMPACT BUFFER WETLAND B 240 SF ENHANCEMENT TO BE ENHANCED 700 SF 1,765 SF BUFFER ADDITION 1,092 SF DEVELOPMENT ENGINEERING msippo 05/10/2022 INTRODUCTION The subject property is composed of five King County tax parcels (3345700015, 3345700016, 3345700017, 3345700018, 3345700020). The site is approximately 10.1-acres, located at and adjacent to 8314 110th PI SE and 4130 Lincoln Ave NE in the City of Renton, Washington (Section 32, Township 24N, Range 5E, W M.). Access is via a driveway from Lincoln Ave NE. SITE DESCRIPTION The subject property is located within the May Creek sub -basin of the Cedar River/Lake Washington Watershed (WRIA 8). Lake Washington is approximately 3,000 feet west of the subject property. Surrounding land use is mixed, including residential, commercial, and industrial uses; with 1-405 approximately 1,100 feet to the west. The site is partially developed; in the south, there are multiple single-family residences and associated infrastructure, while the northern portion contains naturally vegetated pasture and forested areas. Topography slopes steeply to the west, and, according to King County iMap, is underlain by high erosion hazard areas, with slopes in excess of 20 percent. Four wetlands (Wetlands A through D) and one stream (Stream S) were identified within the investigation area. Pursuant to Renton Municipal Code (RMC), on -site wetlands were classified under the Washington State Wetland Rating System for Western Washington: 2014 Update (Hruby 2014). Wetlands A through D are classified as Category IV wetlands. Per RMC (7)(a) Stream S was classified based on the WAC 222-16-030. As such, Stream S is classified as a Type Np Stream. Per 4-3-050(G)(2), Category IV wetlands typically receive 50-foot buffers (when adjacent to non -low impact land uses) and Type Np streams typically receive 75-foot buffers. In addition, geological hazards were identified on -site by the geotechnical engineer, Terra Associates, Inc. Geological hazards identified include protected slopes, high erosion hazard area, and low seismic hazard area. Per RMC 4-3-050G(2), protected slopes require a 15 foot structure setback. PROJECT DESCRIPTION The applicant is proposing to develop a 56-lot residential development and associated infrastructure. To accommodate this development, the applicant will do a combination of buffer width averaging and wetland/buffer impacts, to be mitigated for on -site. As a result of required frontage improvements and stormwater infrastructure, the applicant will permanently impact the entirety of Wetland A (and a portion of an associated ditch), totaling 1,585 square feet, and a small portion (240 square feet) of Wetland B's buffer. In addition, the applicant will utilize buffer averaging to accommodate the proposed development adjacent to Wetland B, Wetland D, and Stream S. As mitigation for the impacts, the applicant is proposing a combination of on -site and off -site mitigation. A portion of the compensation (meeting City of Renton requirements) for Wetland A impacts will be provided by enhancing the entirety of the on -site portions of Wetlands B and D (totaling 4,865 square feet). This exceeds the 3:1 (enhancement to impact) ratio for Category IV wetlands, per RMC 4-3-050(J)(4)(c). The aforementioned impact to the buffer of Wetland B will be mitigated for via enhancement of 700 square feet of buffer located between Wetland B and Lincoln Ave NE (exceeding the 1:1 mitigation to impact ratio required by RMC 4-3-050(J)(4)(d)). To accommodate Stream S buffer width averaging, the applicant proposes to enhance a 6,788 square feet of stream buffer, per RMC 4-3-050(1)(2)(b)(v). As part of the proposed development the City of Renton is requiring an on -site and off -site trail to connect the development to the City of Newcastle's pedestrian trail located along the NE 43rd Street right-of-way, north of the subject property. The off -site portion of the trail will be located within the unopened right-of-way of 112th Avenue SE, that parallels the eastern property boundary. The trail shall be 5 feet wide, with the majority consisting of wood chips underlain with filter fabric, and will be field fit to avoid trees. The trail will cross portions of wetland, stream, and buffer. Per RMC 4-3-050C(3) and RMC 4-3-050C(4), trails are exempt and allowed within critical areas and their associated buffers as long as they meet certain requirements. The portion of trail crossing the wetland will consist of a boardwalk and supported by pin piles. The slatted decking of the boardwalk and grated top of the dock will allow precipitation to move through the structure. This design minimizes impacts to the wetland and aquatic area and avoids any fill or grading within the wetland. Disturbance within the wetland will be limited to vegetation impacted for boardwalk installation. This portion of the trail will impact approximately 134 square feet of vegetation associated with Wetland D. To mitigate for any temporal loss of vegetation from installation of the boardwalk, buffer enhancement of a portion of Wetland D's on -site buffer is proposed at a 3:1 enhancement to impact ratio. The bridge proposed over Stream S will be approximately 6 feet wide and will consist of concrete slabs and metal railings. The crossing will be consistent with WDFW stream crossing guidelines. PROJECT MONITORING PROGRAM Requirements for monitoring project: 1. Initial compliance/as-built report 2. Site inspection (twice per year) for five years 3. Annual reports (one report submitted during each monitored year) Purpose for Monitoring The purpose for monitoring this mitigation project shall be to evaluate its success. Success will be determined if monitoring shows at the end of five years that the definitions of success stated below are met. The property owner shall grant access to the mitigation area for inspection and maintenance to the contracted landscape and/or wetland specialist and City of Renton during the monitoring period or until the project is evaluated as successful. Monitoring Monitoring shall be conducted twice annually for five years in accordance with the approved Mitigation Plan. The monitoring period will begin once the City receives written notification confirming the mitigation plan has been implemented and City staff inspects the site and issues approval of the installation. Vegetation Monitoring Sampling points or transects will be established for vegetation monitoring and photo points will be established from which photos will be taken throughout the monitoring period. Permanent sampling points must be identified on the mitigation site plans in the first monitoring report (they may be drawn on approved plans by hand). Each sampling point shall detail herbaceous, shrub, and tree coverage. Monitoring of vegetation sampling points shall occur once per monitored year. Wetland Hydrology Monitoring To ensure that wetland hydrology is not impacted by the development, the wetland boundaries will be reviewed during the spring monitoring visit of each monitored year. If it appears that any existing wetland areas are no longer saturated or inundated for sufficient duration to support wetland conditions, those areas will be demarcated in the field and depicted on a map. Additional mitigation may need to be provided, as described in the contingency plan in Section 15, below. Photo points No less than four permanent photo points will be established within the mitigation areas. Photographs will be taken from these points to visually record condition of the mitigation areas. Photos shall be taken annually between May 15 and September 30 (prior to leaf drop), unless otherwise specified. MONITORING REPORT CONTENTS Monitoring reports shall be submitted by December 31 of each year during the monitoring period. As applicable, monitoring reports must include descriptions / data for: 1. Site plan and vicinity map 2. Historic description of project, including date of installation, current year of monitoring, restatement of mitigation/restoration goals, and performance standards 3. Plant survival, vigor, and areal coverage for every plant community (transect or sampling point data), and explanation of monitoring methodology in the context of assessing performance standards 4. Wetland and buffer conditions, e.g., surrounding land use, use by humans, and/or wild and domestic creatures 5. Observed wildlife, including amphibians, avians, and others 6. Assessment of nuisance / exotic biota and recommendations for management 7. Color photographs taken from permanent photo -points that shall be depicted on the monitoring report map PROJECT SUCCESS & COMPLIANCE Criteria for Success Upon completion of the proposed mitigation project, an inspection by a qualified biologist will be made to determine plan compliance. A compliance report will be supplied to the City of Renton within 30 days after the completion of planting. A pp Y Y p p g landscape professional or wetland professional will perform condition monitoring of the plantings in the spring and fall of each monitored year. A written report describing the monitoring results will be submitted to the City after each site inspection of each monitored year. Final inspection will occur five years after completion of this project. The contracted consultant will prepare a report as to the success of the project. Definition of Success The planting areas shall meet the following performance standards: a) End of Year 1 • 100 percent survival of newly planted species and • Less than 10 percent cover of weedy/invasive species b) End of Year 2 • 80 percent survival of newly planted species • Less than 10 percent cover of weedy/invasive species c) End of Year 3 • At least 50 percent native vegetation coverage within the mitigation areas* • Less than 10 percent cover of weedy/invasive species d) End of Year 5 • At least 80 percent aerial cover of native woody plant species*, • Less than 10 percent cover of weedy/invasive species. *Volunteering native species may be included in the aerial cover calculations. The species mix should resemble that proposed in the planting plans, but strict adherence to obtaining all of the species shall not be a criterion for success. PROJECT NOTES Pre -Construction Meeting Mitigation projects are typically more complex to install than to describe in plans. Careful monitoring by a wetland professional for all portions of this project is strongly recommended. Construction timing and sequencing is important to the success of this type of project. There will be a pre -construction meeting on this site between the Permittee, the consulting wetland professional, and laborers. The objective will be to verify the location of erosion control facilities, verify the location of mitigation areas, and to discuss project sequencing. Inspections A wetland professional shall be contracted to periodically inspect the mitigation installation described in this plan. Minor adjustments to the original design may be necessary prior to and during construction due to unusual or hidden site conditions. A City of Renton representative and/or the consulting professional will make these decisions during construction. CONTINGENCY PLAN If 20% of the plants are severely stressed during any of the inspections, or it appears 20 percent may not survive, additional plantings of the same species may be added to the planting area. Elements of a contingency plan may include, but will not be limited to: more aggressive weed control, pest control, mulching, replanting with larger plant material, species substitution, fertilization, soil amendments, and/or irrigation. LARGE WOODY DEBRIS In addition to the enhancement plantings, a minimum of two (2) pieces of woody debris (per wetland) will be added to Wetlands B and D. If possible, material removed from the site for development will be salvaged for use as woody debris within the buffer enhancement area. Woody debris shall consist of coniferous logs or root wads. Minimum size of the woody debris will be 10-inch diameter and 15 feet in length, or 10-foot diameter root -wads. TYPICAL LARGE WOODY DEBRIS PLACEMENT 'LWO-LOG, FLALUKL DEIAIL THREE -LOG FFAI'UKF DE TAIL No Sc-,de NOTES: 1) LOGS TO BE A MINIMUM OF 10" IN DIAMETER AND MINIMUM 15' LENGTH 2) EACH CLUSTER SHALL INCLUDE 2-3 LOGS OF DIFFERING DIAMETCoc 3) LOGS WITH ROOTWADS SHALL BE SET IN A SLIGHT DEPRESSION RA 17988 or107