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HomeMy WebLinkAboutLUA-08-014_Misc 2CITY OF RENTON January 6, 2009 Thomas Thompson AIA Consulting Architect 2961915thAvenueNE Stanwood, W A 98292 SUBJECT: Walgreen's on NE 4th Strcet LUA08-014, SA-A, ECF Department of Community and Economic Development Alex Pietsch, Administrator Approval of Final Wetland alld Stream Mitigation and Monitoring Plan Dear Mr. Thompson: Thank you for submitting the Final Wetland and Stream Buffer Mitigation Plan for the subject project. At this time, the Final Mitigation alld Maintenance and Monitoring proposal has been approved by the City of Renton. Please tlnd enclosed your stamped copy of the approved plans. You may commence installation of the proposed mitigation. After installation of the mitigation, please have your contracted biologist submit a letter verifYing that the mitigation installation complies with the approved Final Wetland and Stream Buffer Mitigation Plan. If any portion of the installed mitigation is different then the approved plan, please have your biologist submit an "as built" plan set with the compliance letter and a biological justification for the changes to the approved plan. Once the mitigation installation has becn vcrified as consistent with the approved mitigation plan by the project biologist, the City will then require the applicant to submit draft maintenance and monitoring contracts for the City's approval. Once you have a final, signed, City-approved maintenance and monitoring contract for the subject work, the City will request a surety device in the amount of 125% of the approved contract. If you have any questions, please contact me at (425) 430-7314. Sincerely, -lI~{)afk Vanessa Dolbee Associate Planner EncI: Approved Final Wetlalld & Stream Mitigation and Monitoring Plan cc: Car Wash Enterprises, Inc., Les Schwab Profit Sharing Rertirement Trust I Owners Skyler Waldal! Party of Record -------------I-O-55--S0-u-th-G-r-ad-y-w--aY-.-R-e-n-to-n-.w-·-as-h-in-gt-on--9-80-5-7-------------~ * This papercontall1s 50 Q /" recycled material, 30% post GOflsumer AHEAD OF THE CURVE Final Wetland and Stream Buffer Mitigation Plan Proposed Walgreens at NE 4th Street and Union Avenue NE Renton, Washington November 26,2008 SHANNON &WILSON,INC. QEO,ECHNICAL AND ENVIROtU,U;:NTAL CONSULTANTS Excellence. Innovation. Service. Value. Since 1954. Submitted To: Mr. Thomas Thompson, AlA 29619 15th Avenue NE Stanwood, Washington 98292 By: Shannon & Wilson, Inc. 400 N 34th Street, SUite 100 Seattle, Washington 98103 21-1-12244-001 j j j j j j j j j j j j j j j j j j j j j j j j j SHANNON &WJLSON.INC. TABLE 01<' CONTENTS Page 1.0 INTRODUCTION ................................................................................................................. 1 2.0 SITE DESCRIPTION AND PROJECT HISTORY .............................................................. 1 3.0 PROPOSED PROJECT ......................................................................................................... 2 4.0 FINAL WETLAND AND STREAM BUFFER MITIGATION ........................................... 2 5.0 FUNCTIONS AND VALUES ASSESSMENT .................................................................... 3 5.1 Existing Conditions .................................................................................................... 5 5.2 Proposed Buffer Averaging Conditions ..................................................................... 5 6.0 PLANTING PLAN ................................................................................................................ 7 7.0 RESTORATION SEQUENCE .............................................................................................. 7 8.0 MAINTENANCE .................................................................................................................. 8 9.0 MONITORING PLAN .......................................................................................................... 9 10.0 SUCCESS CRITERIA ......................................................................................................... 1 0 10.1 Year One -Quarterly Monitoring ............................................................................ 11 10.2 Years Two through Five -Annual Monitoring ........................................................ 11 11.0 CLOSURE ........................................................................................................................... 12 12.0 REFERENCES ..................................................................................................................... 13 LIST OF TABLES Table No. 1 Planting Plan for Restoration Area .......................................................................... 3 2 Seed Specifications for Restoration Area ................................................................ 3 3 On-site Wetland and Stream Buffer Functions and Values Matrix ......................... 6 21-1-12244-00 1-R 1 f-Rev .docJwplLKD 21-1-12244-001 TABLE OF CONTENTS (cont.) SHANNON &W1LSON.ING. LIST OF FIGURES Figure No. I Site Vicinity Map 2 Proposed Site Plan and Buffer Map 3 Final Planting Plan Typical LIST OF SHEETS Sheet No. I Final Wetland and Stream Buffer Mitigation Plan -Detailed Planting Plan 2 Proposed Site Plan and Buffer Map APPENDIX Important Infonnation About Your Wetland Delineation/Mitigation and/or Stream Classification Report 21-1-12244-00l-Rl f-Rev.doc/wpiLKD 21-1-12244-001 11 SHANNON &WILSON.INC. FINAL WETLAND AND STREAM BUFFER MITIGATION PLAN PROPOSED WALGREENS AT NE 4TH STREET AND UNION AVENUE NE RENTON, WASHINGTON 1.0 INTRODUCTION As part of a proposed site redevelopment for Walgreens, a wetland and stream buffer will be reestablished along the eastern edge of the site, which is currently paved. This final wetland and stream buffer mitigation plan has been prepared by Shannon & Wilson, Inc. in accordance with the City of Renton's (City's) Environmental Regulations. The objective of this mitigation plan is to reestablish a native plant community typical of the surrounding undisturbed buffer. The scope of work for this mitigation plan is based on our proposal to Mr. Thomas Thompson, dated December 26, 2007. 2.0 SITE DESCRIPTION AND PROJECT HISTORY The proposed Walgreens property (herein referrcd to as "the site") includes King County Parcel Nos. 518210-0008 and -0009, located on the southeast comer of the intersection at NE 4th Street and Union Avenue NE within the City of Renton, Washington. It is approximately 1.17 acres and is located within the NW 14 Section 15, Township 23 North, Range 5 East, Willamette Meridian (Figure I). Maplewood Creek flows northwest to southeast through the site within a buried culvert. The creek daylights immediately east ofthe property and continues in a southeasterly direction within a shallow channel. The site is predominantly paved, with the exception of small, landscaped amenities, and slopes gradually eastward. On-site catch basins capture and convey stonnwater directly to the culvert. East of the site, an unnamed, seasonal tributary to Maplewood Creek runs southward, parallel to the property boundary before its confluence with Maplewood Creek. The off-site reach of Maplewood Creek is bounded by a wetland. Maplewood Creek and its tributary are considered Class 4 streams under the City's Renton Municipal Code (RMC). The off-site wetland is considered a Category 2 wetland under the RM C. Buffers for the Class 4 streams and Category 2 wetland extend onto the east side of the site (Figure 2). 21-1-12244-00 loR! f-Rev.doc/wp/LKD 21-1-12244-001 SHANNON &W1LSON.INC. Under the RMC, redevelopment of the site is required to comply with the City's Environmental Regulations, which require all non-conforming structures within critical areas (e.g., wetland and stream buffers) to be removed. 3.0 PROPOSED PROJECT The proposed redevelopment of the site would include constructing a Walgreens drug store and associated parking. To the south of the site is an existing Les Schwab tire business and associated parking areas. The proposed redevelopment would also include modification of existing parking and traffic flow through the site and the Les Schwab property. The current site plan for the proposed Walgreens (Figure 2 and Sheet 1) has been designed to avoid impacts to the on-site, culverted reach of Maplewood Creek and to reestablish the wetland and stream buffer along the eastern portion of the site. The proposed Walgreens has been located away from the buried stream; theretore, no stream mitigation will be required. Mitigation will be required as part of the redevelopment for that portion of wetland and stream buffer that is currently paved. The following wetland and stream buffer mitigation plan addresses this required mitigation. 4.0 FINAL WETLAND AND STREAM BUFFER MITIGATION The redevelopment of the site for the proposed Walgreens will require reestablishing a minimum of2,849 square feet of wetland and stream buffer along the eastern portion of the site. Under the RMC, buffer modification may occur through buffer averaging or buffer reduction. The proposed site plan has been designed to accommodate buffer averaging. The standard wetland and stream buffers, as well as the proposed buffer-averaging configuration, are shown in Figure 2 and Sheet 1. Wetland and stream buffer averaging are allowed under RMC 4-3-050(L)5d and 4-3-050(M)6f provided that (a) the proposed buffer averaging area remains contiguous and (b) there is no decrease in net area of the buffer. The proposed buffer averaging configuration shown in Figure 2 and Sheet I provides a total of 3,030 square feet of reestablished buffer along the eastern edge of the site. To reestablish that portion of on-site buffer, pavement and subgrade within the proposed buffer averaging area will be removed, and native tree, shmb, and herbaceous species will be installed according to the specifications provided in Tables I and 2. A cedar split-rail fence will be 21-J-12244-DOI-R 1 f-Rev.doc/wp/LKD 21-1-12244-001 2 SHANNON &WILSON,INC. installed around the perimeter of the reestablished wetland and stream buffer area to reduce pedestrian intrusion into the buffer. A detail of the fence design is provided in Sheet I. Signage identifying the reestablished buffer as a critical area will be placed on the fence at approximately 50-foot intervals. TABLE 1 PLANTING PLAN FOR RESTORATION AREA REESTABLISHED BUF,FER Common Name Scientific Name Quantity Size Condition Spacing Douglas fIr Pseudotsuga menziesij 20 >3 feet 2-gallon pot 9 feet O.C. Big-leaf maple Acer macrophyllum 20 >3 feet 2o gallon pot 9 feet O.C. Scouler willow Salix scouleriana 75 12+ inches I-gallon pot 4 feet O.C. Indian plum Oem/eria cerasiformis 25 12+ inches 1-to 2-gallon pot 4 feet O.C Lewis' mock orange Philadelphus lewisii 75 12+ inches 1-to 2-g.llon pot 4 feet O.C. Tall Oregon grape Mahonia aquifolium 25 12+ inches 1-to 2-gallon pot 4 feet O.C Nootkarose Rosa nutkana 77 12+ inches 1-to 2-gaHon pot 4 feet O.C. Q,C. = on center TABLE 2 SEED SPECIFICATIONS FOR RESTORATION AREA . ... NATIVE BUFFER SE:E;nMUC •• CODllnonName .. Scientific N arne > ~ercel1i:byWeight, PLS California brome Bromus carinatus 10% Blue wild rye Elymus glaucus 60% Red fescue Festuca rubra 30% PLS = pure live seed 5.0 FUNCTIONS AND VALUES ASSESSMENT To ensure that this final wetland and stream buffer mitigation plan complies with those requirements for buffer averaging under RMC 4-3-050(M)6f and RMC 4-3-050(5)d, a functions and values assessment is required. This requirement is to ensure that the ecological integrity of ... 21-1-12244-001-RI f-Rev.docJwplLKD 21-1-12244-001 3 • SHANNON &WILSON.INC. the buffer and its adjacent critical area (wetland and/or stream) are protected from the proposed activity to the greatest extent practical. To adequately assess functions and values of the on-site portion of the buffer, the adjacent buffer and site conditions must be taken into account. The off-site buffer to the east of the site is associated with Maplewood Creek and Wetland A and varies in ecological sensitivity and existing level of disturbance. Along the southeast portion of the project site, the wetland and stream buffer consist of a mixed-forest canopy, which is dominated by black cottonwood (Populus trichocarpa) and Douglas fir (Pseudotsuga menziesii) trees. Native shrubs, such as Indian plum (Oemleria cerasiformis), salmonberry (Rubus spectabilis), and red-osier dogwood (Cornus sericea), are located within the forest understory. Along the western edge of this forested buffer, which abuts the site, vegetation includes more disturbed species such as Himalayan blackberry (Rubus armeniacus), as well as garbage and debris from illegal dumping. Along the northeast boundary of the project site, the wetland and stream buffer begins to steeply slope down towards Maplewood Creek and Wetland A. Vegetation throughout this portion of the off-site buffer is dominated by species typical of disturbed conditions, such as Himalayan blackberry (Rubus armeniacus) and butterfly bush (Buddleia davidii). Garbage and debris are located throughout this portion of the buffer. The majority of standard wetland and stream buffer associated with Maplewood Creek and Wetland A is located in this portion of the site. A buffer mitigation plan developed for the adjacent Former Ribera site is currently being installed, which changes the current conditions of the off-site buffer along the northeastern portion ofthe site. Through the buffer mitigation plan associated with the Former Ribera site, many of the non-native shrubs are being removed and replaced with native shrub species. The following functions and values assessment compares the existing and proposed buffer functions and values conditions. To accomplish a functions and values assessment for that portion of the buffer extending onto the site, the Wetland and Buffer Functions Semi- Quantitative Assessment Methodology (SAM) (Cooke, 2002) was referenced. Due to the size of buffer on site in context to the total wetland and buffer area, the SAM methodology was not appropriate to assess changes to such a small area. However, those functions included in the SAM were used to qualitatively assess the existing and proposed buffer conditions. These functions and values include flood/storm water control, base flow/groundwater support, erosion/shoreline protection, water quality improvcment, natural biological support, overall habitat support, specific habitat functions, and cultural/socioeconomic values. These changes to 21-1-12244-001-RI f-Rev.doc/wp/LKD 21-1-12244-001 4 SHANNON &WILSON.INC. these functions and values are also summarized for both existing and proposed conditions as a matrix in Table 3. 5.1 Existing Conditions The current on-site portion of standard wetland and stream buffer (2,849 square feet) is paved and interrupted from the off-site buffer by curbs. A few landscaped conifers are located in patches throughout the existing car wash site; however, these landscaped patches are outside of the on-site portion of standard wetland and stream buffer. This standard buffer configuration is largely limited to that portion in the immediate vicinity of Maplewood Creek where it exits the buried culvert and flows through Wetland A, east of the site. The current standard on-site buffer configuration provides no low floodlstorrnwater control functions, base flow/groundwater support functions, water quality improvement functions, overall habitat functions, specific habitat functions, or cultural/socioeconomic values. No natural biological support functions or overall habitat functions are provided by the current standard on- site buffer. However, the on-site standard buffer does provide moderate erosion/shoreline protection (see Table 3). 5.2 Proposed Buffer Averaging Conditions The proposed buffer averaging site conditions will provide a band of buffer along the eastern edge ofthe site ranging from approximately 5 to 25 feet in width. The widest portion of buffer will be located near the outfall of Maplewood Creek. The proposed buffer averaging configuration will provide improved functions and values relative to existing conditions. This includes providing moderate flood/storrnwater control, base flow/groundwater support, erosion/shoreline protection, water quality improvement, natural biological support, overall habitat support, specific habitat functions, and cultural/socioeconomic values (see Table 3). Therefore, the proposed buffer averaging configuration will result in a net increase in functions and values. 21-J-12244-001-RI f-Rev.doc/wp/LKD 21-1-12244-001 5 Rainfall falling on the current standard buffer area (paved parking and roadways) generally results in stonnwater that drains to a catch basin on site, which discharges directly to Maplewood Creek and eventually to Wetland A. Some rainfall that reaches the standard buffer area will evaporate from the paved surface. No rainfall interception or infiltration currently occurs. FV Score ~ Moderate Rainfall falling on the proposed buffer averaging configuration will be intercepted by installed native plantings, infiltrated into restored topsoil, or result in minor surface flow down slope into Wetland A, Tributary A, or Maplewood Creek. As native plantings become established, the roots of this vegetation will increasingly utilize infiltrated rainfall, stabilize the on-site slopes, and increase the complexity of hydrologic functions. values are assessed * FV Score = Functions and Values Score 21-J -J2244-001-R 1 f-Rcv.doc/wplLKD TABLE 3 ON-SITE WETLAND AND STREAM BUFFER FUNCTIONS AND VALUES MATRIX The current standard buffer area provides no base flow/groundwater support since it is entirely paved and stonnwater enters Maplewood Creek without infiltrating or reeei ving detention. FV Score ~ Moderate Rainfall that falls on the proposed buffer averaging configuration will, in part, infiltrate into the imported topsoil. This will provide a small degree of base flow and groundwater support to Maplewood Creek and Wetland A. Due to the site's being entirely paved, with curbs along the eastern perimeter under current conditions, no surface flow exits the site to the east to create erosion and sedimentation. However, due to the current site configuration, the off-site buffer slopes steeply down to Maplewood Creek and Wetland A. FV Score ~ Moderate Under the proposed buffer averaging conditions, native plantings will be installed tluoughout. As this vegetation matures, the root structure from this vegetation will provide inaproved soil stability along the slope down to Map lewood Creek and Wetland A. Additionally, this mitigation plan calls for the slope from the eastern edge of the site to be graded to a more gradual slope. Through these measures, the erosion! shoreline protection functions provided by the existing buffer conditions will be improved. Rainfall occurring on the current standard buffer area (paved parking and roadways) results in stormwater that drains to a catch basin on site, which discharges directly to Maplewood Creek and eventually Wetland A. Pollutants such as dissolved metals, hydrocarbons, and total suspended solids become entrained in the stonnwater from on-site parking and roadways before entering the Maplewood Creek and Wetland A. FV = Model'ate Rainfall occurring on the proposed buffer averaging configuration will interact with the installed, native plantings and top soil. This area of buffer will reduce the current area of pollutant- generating surface. Rainfall that reaches the proposed buffer "take" areas (that portion of the standard buffer not included in the proposed buffer averaging configuration) will runoff as stonnwater. Stonnwater from the site treated prior to being released to Maplewood Creek, will improve the quality of water entering Maplewood Creek. and are on a comparison between existing conditions and proposed 6 Natural biological support functions are intended to reflect the connectivity, vegetation, surface water presence, community types, plant diversity, percent of invasive species, organic material production, habitat features, and buffer condition. Due to the current site conditions (paved parking and roadways), no natural biological support functions are currently provided. FV Score ~ Moderate Under the proposed buffer averaging configuration, the buffer will connect to the off- site buffer and has been designed to complement the mitigation plan developed for the adjacent Former Ribera property, providing a diverse variety of native plantings that offer structural complexity and improved wildlife habitat for the buffer. Through this buffer mitigation plan, the buffer will begin to produce and export organic materials and improve the overall condition of the buffer. The "overall habitat functions" are intended to reflect the habitat diversity and percentage of sanctuary or refuge offered by the current site conditions. Due to the site's being entirely paved, no overall habitat functions are provided currently. FV Score ~ Moderate Through the revegetation with several native plant species, the buffer will improve the current site habitat diverSity and provide sanctuary and refuge by creating new niches for wildlife not currently offered on site. SHANNON & WILSON, INC. The current standard buffer area provides minimal specific habitat functions. The habitat provided on site is suitable for edge species that have adapted to urban areas adjacent to small forest areas. This includes species such as raccoon, brewer's blackbird, and European starling. FV Score ~ Moderate While the wildlife habitat provided by the site will remain suitable for edge species, the proposed buffer averaging configuration will provide improved biodiversity tluough native plantings. Through the installation of native plantings, new niches will be created for additional wildlife species, namely songbirds. The current standard buffer area provides minimal cultural! socioeconomic values. Residents and USers of the site are able to get close access to the Tributary A, Wetland A, and Maplewood Creek; however, no signage is provided to educate those residents and users of the importance of these natural resources. FV Score = Moderate Under the proposed buffer averaging configuration, the buffer will be fenced off to the public. However, signs will be placed along the perimeter of the fence to educate residents and users of the site of Maplewood Creek and the sensitive habitat provided by the wetland and stream. 21-1-12244-001 SHANNON &WILSON, INC. 6.0 PLANTING PLAN The planting plan is designed to establish native, non-invasive plant species in the reestablished buffer. The plant species selected for this area are native to the project area and have displayed a high degree of success in similar restoration projects. See Table 1 for the plant species selected and Table 2 for the native seed mix that should be applied. The planting plan calls for the installation of 317 native woody plants to be placed throughout the reestablished buffer. Planting should bc done by hand in natural, randomized clusters. All vegetation should be installed the samc day the plants are obtained. Plants that cannot be planted within one day after arrival should be "heeled in" for protection against drying. For best results, planting should occur during the fall or winter seasons (October to February) when plants are most dormant and have the greatest potential for survival. The seed mix should be applied at 80 pounds of pure live seed (PLS) per acre. Based on the area of proposed reestablished buffer (3,030 square feet), this would equal approximately 6 pounds of seed mix required. This seed mix will help encourage the introduction of native grass and herbaceous species throughout the reestablished buffer. Seeds must be thoroughly mixed before being hand broadcast throughout the reestablished buffer. For best results, seeding should occur between June and August, assuming irrigation is provided. 7.0 RESTORATION SEQUENCE The restoration sequence is as follows: A. Remove asphalt and subgrade from buffer-averaging areas. B. During grading, overexcavate the upper 1 foot of underlying soils and transition the slopes with the off-site topography. Place I toot of compost-amended topsoil (Cedar Grove or equivalent) over the graded buffer. C. Install woven jute matting along thc slopc along the northeastern portion of the site where slopes are steep to provide additional soil stability and to reduce the potential for the herbaceous seed mix (Table 2) to be washed off site. Rolls of jute matting (4 feet wide and 225 feet long) are available at Layfield Plastics, Inc. in Renton, Washington. D. Procure restoration plants and native seed, as specified in Tables I and 2, from a registered nursery (e.g., Sound Native Plants or Stonn Lake Growers) or through a licensed landscaper. Procured plant material should not be allowed to become desiccated throughout the restoration sequence; theretore, irrigation should not be limited to post- installation because desiccation will ultimately reduce the success of the mitigation. 21-1-12244-00\-RI f-Rev_doc!wplLKD 21-1-12244-001 7 SHANNON &WILSON.INC. E. Place plants within the reestablished buffer in natural, random clusters, as shown schematically in Figure 3 and Sheet I. Dig a square-bottomed hole for each plant, twice the size of the container, and score edges of planting hole with shovel, so root growth is encouraged outside the hole. If necessary, cut a hole into the jute matting prior to digging the hole. Loosen plant roots slightly, and place root ball in center of hole, upright and level with ground surface. Backfill the hole with the remaining compost-amended soil tightly enough to remove air pockets from the disturbed soil, but loose enough to allow for drainage. F. Hand broadcast the native grass seed mix specified in Table 2 throughout the reestablished buffer. G. Irrigate plants thoroughly (King County recommends watering the restoration area with 2 inches of water immediately following planting). H. Mulch a 3-ineh-deep, 2-foot radius around the base of each plant with wood chip mulch. I. Install a temporary, aboveground irrigation system calibrated to provide 2 inches of water per week to the reestablished buffer between July IS and October IS for the first two growmg seasons. J. Install the cedar split-rail fence along the perimeter of the buffer mitigation areas. Signage specified by the City should be affixed to the split-rail fence at 50-foot intervals. After the planting is completed, a wetland biologist should prepare an as-built or record drawing for the City's files. Receipts for installed plant material should also be retained. The appliCant should submit the as-built drawing and plant material receipts to the City and request an inspection. 8.0 MAINTENANCE The following maintenance activities should be performed to ensure that the restoration is successful and to comply with City standards: A. Irrigate the restoration area with an aboveground irrigation system calibrated for 2 inches of water every week from June 15 to October 15 during the first two years after planting. B. At the end of the first year, complete a comprehensive plant count. This count should be completed by a wetland biologist and made available to a representative of the landscape contractor. The comprehensive plant count should determine the degree of plant mortality during the first year throughout the entire reestablished buffer area. All plant mortalities should be replaced during the fall or winter following the first year after plant installation. Under normal circumstances, this plant replacement should be 21-1-12244-00l-R 1 f-Rev .doc/wp/LKD 21-1-12244-001 8 SHANNON &WILSON.INC. covered under the landscaper's one-year plant guarantee. Those plants not covered by the landscaper's guarantee should be replaced at the owner's expense. C. Remove nuisance weeds, such as Himalayan blackberry (Rubus armeniacus) and English ivy (Hedera helix), by hand from the mitigation area throughout all five years of the monitoring program to ensure the success of the installed vegetation. Herbicides may not be used unless specifically allowed by the City. If herbicide is approved by the City, its application must be performed by a licensed applicator, and all local, state, and federal permits should be obtained. D. Remove all noxious weeds as defined by the King County Noxious Weed List (http://dnr.metrokc.gov/wlr/lands/weeds/weedlist.cfm) for five years after planting. These include but are not limited to Japanese knotweed (Polygonum cuspidatum), Scots broom (Cytisus scoparius), hedge bindweed (Calystegia sepium), purple loosestrife (Lythrum salicaria), and sulfur cinquefoil. None of these noxious weeds currently exist on site; however, these species have been observed in the site vicinity. Specifically, sulfur cinquefoil (Potentilla recta) and Scots broom (Cytisus scoparius) have been observed east of the site. E. Remove all garbage and debris from the site and dispose of them at a facility certified to handle such waste. 9.0 MONITORING PLAN The primary purpose of the monitoring plan is to document the degree of success or failure in the reestablished buffer and to identify and implement remedial actions to ensure that the goals of the mitigation plan are achieved. A five-year monitoring program will be implemented, as required by the City, to assess the completed revegetation area and to provide a basis for determining whether the plants are surviving and the goals of the mitigation plan are being met. The five-year monitoring program requires quarterly monitoring events and reports during the first year and then annually thereafter, for a minimum of five successful years of maintenance and monitoring. Monitoring reports should identify and address of the following: A. Percent of plant survival amongst installed shrub and tree species. Classify plant survival amongst installed shrub and tree species by condition (e.g., vigorous, living, stressed, dead). Quantitative monitoring will occur within representative vegetation sampling transects for all five years within the reestablished buffer. To accomplish accurate plant survival calculations, installed vegetation should be flagged annually to facilitate relocation during future monitoring events. 21-1-12244-00I-R I f-Rev.doclwplLKD 21-1-12244-001 9 SHANNON &WILSON.INC. Note: "Percent of plant survival" is not intended to mean the survival of planted material initially installed by the landscape contractor. Instead, it is intended to reflect the percentage ofliving tree and shrub species (not including recruited species) within the representative sampling transects relative to the number of tree and shrub species recorded during the baseline monitoring event. B. Percent areal coverage of installed and volunteer shrub and tree species. Quantitative monitoring of installed and voluntecr tree and shrub species within the reestablished buffer will occur for all five years, in accordance with the City's timing requirements. To accurately calculate percent areal coverage, the point-intercept methodology will be used at three 50-to 100-foot-long, repeatable and representative, vegetation sampling transects located within the reestablished buffer. C. Percent areal coverage ofseedetl and recruited herbaceous species. Quantitative monitoring will occur for the first two years ofthe performance monitoring period within representative vegetation sampling transects throughout the wetland and buffer enhancement areas. D. Qualitative photographs. The enhanced wetland and buffer areas will be photographed from locations where photographs can be repeated during future site visits to qualitatively document and assess the success of the wetland and buffer enhancement throughout the site. E. Wildlife observations. Direct or indirect wildlife observations of the mitigated buffer areas will be documented, including evidence of nesting/denning, browse, audible calls, and scat. F. Maintenance concerns. Maintenance concerns such as, broken irrigation systems, broken fencing, plants that need replacing, noxious weed removal, vandalism, dumping, and other conditions that may be detrimental to thc success of the wetland and stream buffer mitigation, should be reported and fixed. 10.0 SUCCESS CRITERIA Success criteria have been developed for ycar one, when monitoring is required on a quarterly basis, and for years two through five, when monitoring is required annUally. Plant mortality is often at its highest during the first year following planting because of stress to installed plants. Therefore, the success criteria for year onc are designed to allow for the plants to adjust to the conditions ofthe site. The success criteria for the mitigation plan include the following requirements: 21-J-12244-001-Rl f-Rev.doc/wp/LKD 21-1-12244-001 10 SHANNON &W1LSON.INC. 10.1 Year One -Quarterly Monitoring A. No more than 15 percent of plant mortality during any year one quarterly monitoring event or 20 percent plant mortality at the end of the first year will be acceptable. See Item A, Section 8.0 for definition of "percent plant survival." If total plant mortality within thc first year is greater than 15 percent following the comprehensive plant count, appropriate corrective measures should be taken to reduce the potential for further die back. These corrective measures may include substituting plant species, adding soil amendments, and/or re-calibrating temporary irrigation. All plant mortalities that occur after the first year should be replaced during that fall, when plant installation achieves a higher success rate. B. During the summer quarterly monitoring event following seeding, 25 percent cover of installed and recruited non-invasive herbaceous vegetation will be present within representative vegetation sapling transects. C. Himalayan blackberry (Rubus armeniacus). reed canarygrass (Phalaris arundinacea), and English ivy (Hedera helix) will comprisc no more than 15 percent areal cover during any quarterly monitoring event. 10.2 Years Two through Five -Annual Monitoring A. The reestablished buffer will achieve either 85 percent survival or 5 percent areal coverage of native installed and recruited woody vegetation by the end of year two; 85 percent survival or 10 percent coverage of native installed and recruited woody vegetation by the end of year three; 85 percent survival or 15 percent coverage of native installed and recruited woody vegetation by the end of year four; and 85 percent survival or 25 percent coverage of native installed and recruited woody vegetation by the end of year five. B. The reestablished buffer will achieve 50 percent cover by installed and recruited non- invasive herbaceous vegetation by the end of year two. No coverage requirements for herbaceous vegetation are proposed for years three through five. C. Himalayan blackberry (Rubus armeniacus), reed canarygrass (Phalaris arundinacea), and English ivy (Hedera helix) will comprise no more than 15 percent areal cover during years two through four and no more than 10 percent areal cover by the end of year five. D. Noxious weeds will be removed within the mitigation area after each monitoring event. Removal will occur according to the King County Noxious Weed Board recommendations. Noxious weeds are defined by the most current King County noxious weed list, including Class A, B, and C noxious weeds. This success criterion does not pertain to those species classified as nuisance weeds. 21-1-12244-00J-Rl f-Rev.dodwplLKD 21-1-12244-001 11 SHANNON &W1LSON.INC. If any monitoring report or City inspection shows that mitigation is not meeting these performance standards, the applicant will work with the City to perform corrective actions appropriate to the mitigation (e.g., failing plants will be replaced, other plant species will be substituted, and noxious/nuisance weeds will be removed by hand or with approved herbicides provided all local, state, and federal permits are obtained to do so). 11.0 CLOSURE The fmdings and conclusions documented in this report have been prepared for specific application to this project. They have been developed in a manner consistent with that level of care and skill normally exercised by members of the environmental science profession currently practicing under similar conditions in the area. The conclusions and recommendations presented in this report are professional opinions based on interpretation of information currently available to us and made within the operational scope, budget, and schedule constraints of this project. No warranty, express or implied, is made. This report was prepared for the exclusive use of Thomas Thompson and his representatives. We have prepared the document, "Important Information About Your Wetland Delineation! Mitigation Report," (Appendix) to assist you and others in understanding the use and limitations of our reports. SHANNON & WILSON, INC. PC] :BSK:DNC/pej 21 ~ L-12244-001-R I f-Rev.doclwp/LKD 21-1-12244-001 12 SHANNON &W1LSON, INC. 12.0 REFERENCES City of Renton, 2007, City of Renton critical areas regulations: Available: http://www.codepublishing.com/walrenton/. Cooke, Sarah, 2002, Wetland and buffer functions Semi-Quantitative Assessment Methodology (SAM): Available: http://www.cookescientific.com/sam.htm. King County, 2007, King County noxious weed list: Available: http://dnr.metrokc.gov/wlr/lands/weeds/laws.htm. 21-J-12244-001-RI f-Rev.doc/wp/LKD 13 21-1-12244-001 \J.~~ Washington , en ton II3l """' Project- • l l-5! Loc atio n ~- o I 1/4 I 1/2 I z~. ST • em Scale in Miles NOTE '---, 1 J Reproduced wilh permission granted by TH OMAS BROS . MAPS ®. This map is copyrighted by © Ra nd McNa lly, R L 08-S -34. It i s un lawful to co py or reproduce all or any pa rt thereof, whe ther for personal use or resale , without permiss ion . All rights reserved . RON R£G IS PARK 4th and Union Wa lgreens , ~ , , " ! I Final Wetland and Stream Buffer Miti gation Plan Renton , Washington VICINITY MAP w z ~ " .Q " :::J ,. , , , , , , , '''-I -----.. --.. ~ ----------------NE 4th St Unnamed Tributary =--------- (Class 4 Stream) --------------35-Ft Class 4 Stream Buffer--------------- PROPOSED WALGREENS Maplewood Creek within Buried Culvert 50-Ft Wetland Buffer --- I 35-Ft Class 4 Stream Buffer \ ---------- o -- \ ---... r-----------_____ ---- - _ \ \ ---\ LEGEND 1-- - --I Standard Wetland andfor Stream Buffer 1 _____ I (2.849 Square Feet) Proposed Buffer Averaging Configuration (3,030 Square Feet) Proposed Buffer Take Area (1,394 Square Feet) Proposed Buffer Give-Back Area (1,575 Square Feet) NOTE o I I WetlandA \ (Category 2) \ I \ 60 I Scale In Feet 4th and Union Walgreens 120 I Final Wetland and Stream Buffer Mitigation Plan Renton, Washington PROPOSED SITE PLAN AND BUFFER MAP ~ SHANNON & WILSON, INC. FIG 2 C Geotechnical and Environmental Consultants • ~L ________________________________________________________ J--:~~~~~~~ ________ ~ ____________ ~ November 2008 21-1-12244-001 Figure adapted from drawing renton_11-29-07.dwg received 12-12-2007 and electronic files received 1-31-2007, used by permission of 4th Avenue Associates, LLC. u: o 9 ;t N ~ ~ ~ N ~ ~ , ~ E • c ~ o o PLANTING PLAN FOR RESTORATION AREA Big-leaf maple Acer macroph yllum 20 >3-feet 2 gallon 9 feet on center Scouler willow Salix scouleriana 75 12+ inches 1 gallon 4 feet on center Indian plum Oem/eria cerasiformis 25 12+ inches 1-2 gallon 4 feet on center Lewis' mock orange Philadelphus lewisii 75 12+ inches 1-2 gallon 4 feel on center Tall oregongrape Mahonia aquifolium 25 12+ inches 1-2 gallon 4 feet on center Nootka rose Rosa nutkana 77 12+ inches 1-2 gallon 4 feet on center *Quantity based on revegetation of 5,912 square feet of area. SEED SPECIFICATIONS FOR RESTORATION AREA California brome Blue wild rye Red fescue CONTAINER PLANTING DETAIL Bromus carinatus Elymus g/aucus Festuca rubra Planting Mulch Depth Equals 4 Inches 10% 60% 30% PLS = Pure Live Seed 4th and Union Walgreens Final Wetland and Stream Buffer Mitigation Plan Renton, Washington FINAL PLANTING PLAN TYPICAL November 2008 21-1-12244-001 SHANNON & WILSON, INC, FIG 3 Geoledmical end Environmental Consultants • ~L-____________________________________________________ ~ ______________________ " __________ -" SHANNON &WILSON,INC. APPENDIX IMPORTANT INFORMATION ABOUT YOUR WETLAND DELINEA TIONIMITIGA TION AND/OR STREAM CLASSIFICATION REPORT 21-1-12244-001 SHANNON & WILSON, INC. Geotechnical and Environmental Consultants Attachment to and part of Report 21·1-12244-00 I ::111 Date: November 26, 2008 To: Mr. Thomas Thompson, A.LA. Stanwood, Washington IMPORTANT INFORMATION ABOUT YOUR WETLAND DELINEATION/MITIGATION AND/OR STREAM CLASSIFICATION REPORT A WETLAND/STREAM REPORT IS BASED ON PROJECT-SPECIFIC FACTORS. Wetland delineation/mitigation and stream classification reports are based on a unique set of project-specific factors. These typically include the general nature of the project and property involved, its size, and its configuration; historical use and practice; the location of the project on the site and its orientation; and the level of additional risk the client assumed by virtue of limitations imposed upon the exploratory program. The jurisdiction of any particular wetland/stream is determined by the regulatory authority(s) issuing the permit(s). As a result, one or more agencies will have jurisdiction over a particular wetland or stream with sometimes confusing regulations. It is necessary to involve a consultant who understands which agcncy(s) has jurisdiction over a particular wetland/stream and what the agency(s) permitting requirements are for that wetland/stream. To help reduce or avoid potential costly problems, have the consultant determine how any factors or regulations (which can change subsequent to the report) may affect the recommendations. Unless yOUT consultant indicates otherwise, your report should not be used: • If the size or configuration of the proposed project is altered. • If the location or orientation of the proposed project is modified. • If there is a change of ownership. • For application to an adjacent site. ... For construction at an adjacent site or on site. ... Following floods, earthquakes, or other acts ofnature. Wetland/stream consultants carmot accept responsibility for problems that may develop if they are not consulted after factors considered in their reports have changed: Therefore, it is incumbent upon you to notify your consultant of any factors that may have changed prior to submission of our fmal report. Wetland boundaries identified and stream classifications made by Shannon & Wilson are considered prelinrinaryuntil validated by the U.S. Army Corps of Engineers (Corps) and/or the local jurisdictional agency. Validation by the regulating agency(s) provides a certification, usually written, that the wetland boundaries verified are the boundaries that will be regulated by the agency(s) until a specified date, or until the regulations are modified, and that the stream has been properly classified. Only the regulating agency(s) can provide this certification. MOST WETLAND/STREAM "FINDINGS" ARE PROFESSIONAL ESTIMATES. Site exploration identifies wetland/stream conditions at only those points where samples are taken and when they are taken, but the physical means of obtaining data preclude the detennination of precise conditions. Consequently~ the infonnation obtained is intended to be sufficiently accurate for design, but is subject to interpretation. Additionally, data derived through sampling and subsequent laboratory testing are extrapolated by the consultant who then renders an opinion about overall conditions, the likely reaction to proposed constrnction activity, andlor appropriate design. Even under optimal circumstances, actual conditions may differ from those thought to exist because no consultant, no matter how qualified, and no exploration program, no matter how comprehensive, can reveal what is hidden by earth, rock, and time. Nothing can be done to prevent the unanticipated, but steps can be taken to help reduce their impacts. For this reason, most experienced owners retain their consultants through the construction or wetland mitigation/stream classification stage to identify variances, to conduct additional evaluations that may be needed, and to recommend solutions to problems encountered on site. Page 1 of2 1/2007 WETLAND/STREAM CONDITIONS CAN CHANGE. Since natural systems are dynamic systems affected by both natural processes and human activities, changes in wetland boundaries and stream conditions may be expected. Therefore, delincateJ wetland boundaries and stream classifications cannot remain valid for an indefinite period of time. The Corps typically recognizes the validity of wetland delineations for a period of five years after completion. Some city and county agencies recognize the validity of wetland delineations for a period of two years. If a period of years have passed since fhe wetland/stream report was completed, the owner is advised to have fhe consultant reexamine fhe wetland/stream to detennine if the classification is still accurate. Construction operations at or adjacent to the site and natural events such as floods, earthquakes, or water fluctuations may also affect conditions and, fhus, the continuing adequacy offhe wetland/stream report. The consultant should be kept apprised of any such events and should be consulted to detennine if additional evaluation is necessary. THE WETLAND/STREAM REPORT IS SUBJECT TO MISINTERPRETATION. Costly problems can occur when plans are developed based all misinterpretation of a wetland/stream report. To help avoid fhese problems, the consultant should be retained to work wifh ofher appropriate professionals to explain relevant wetland, stream, geological, and ofher findings, and to review the adequacy of plans and specifications relative to these issues. DATA FORMS SHOULD NOT BE SEPARATED FROM THE REPORT. Final data forms are developed by fhe consultant based on interpretation of field sheets (assembled by site personnel) and laboratory evaluation of field samples. Only fmal data forms customarily are included in a report. These data forms should not, under any circumstances, be drawn for inclusion in other drawings because drafters may conunit errors or omissions in the transfer process. Although photographic reproduction eliminates this problem, it does nothing to reduce the possibility of misinterpreting the forms. When this ocCW"S, delays, disputes, and unanticipated costs are frequently the result. To reduce fhe likelihood of data form misinterpretation, contractors, engineers, and planners should be given ready access to fhe complete report. Those who do not provide such access may proceed under the mistaken impression fhat simply disclaiming responsibility for fhe accuracy of infonnation always insulates them from attendant liability_ Providing the best available infonnation to contractors, engineers, and plarmers helps prevent costly problems and fhe adversarial attitudes fhat aggravate them to a disproportionate scale. READ RESPONSIBILITY CLAUSES CLOSELY. Because a wetland delineation/stream classification is based extensively on judgment and opinion, it is far less exact than other design disciplines. This situation has resulted in wholly unwarranted claims being lodged against consultants. To help prevent fhis problem, consultants have developed a number of clauses for use in written ·transmittals. These are not exculpatory clauses designed to foist the consultant's liabilities onto someone else; rather, they are definitive clauses that identify where the consultant 1s responsibilities begin and end. Their use helps all parties involved recognize their individual responsibilities and take appropriate action. Some of fhese defmitive clauses are likely to appear in your report, and you are encouraged to read fhem closely. Your consultant will be pleased to give full and frank answers to your questions. THERE MAY BE OTHER STEPS YOU CAN TAKE TO REDUCE RISK. Your consultant will be pleased to discuss ofher techniques or designs that can be employed to mitigate the risk of delays and to provide a variety of alternatives fhat may be beneficial to your project. Contact your consultant for further information. Page 2 01'2 1/2007