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HomeMy WebLinkAboutEmerald Crest Installation Completion Letter and Report_171128 November 22, 2017 Emerald Crest Board ℅ Angie Bringier Via email: emerald@ciramail.com Via phone: 206-508-6650 x3604 Re: Emerald Crest Wetland Restoration, As-built Report The Watershed Company Reference Number: 160707 Dear Angie: On November 9, 2017, staff from The Watershed Company visited the Emerald Crest wetland restoration site in Renton, Washington. The purpose of the visit was to verify that the wetland restoration plan was installed according to the approved Emerald Crest Wetland Restoration Plan (The Watershed Company. February 2, 2017) (Approved Plan). This letter documents confirmation of the successful installation. Project History The Approved Plan was prepared to rectify a violation issued by the City of Renton for unauthorized clearing and grading in a wetland. A total of 3,827 square feet of wetland was impacted. The approved plan includes planting a mix of trees, shrubs, emergents, and willow stakes that will restore and enhance the affected area as compared to the pre-existing condition. The Critical Areas Exemption was issued by the City on May 9, 2017; however, installation was delayed until the dormant season to coincide with optimal planting conditions. The applicable goals, performance standards, and monitoring methods are provided in the Approved Plan. Results As part of the as-built inspection, a complete plant census of installed vegetation was completed. A total of 408 plantings were installed. This total is less than the 565 plantings called for on the Approved Plan. The discrepancy was discussed with the landscape contractor, and the difference is likely a result of minor deviations in the calculated total planting area; the impact area was measured manually from known reference points and not officially surveyed. However, the density of the installed plants exceeds the four-foot on-center spacing stipulated on the plans. Additional Emerald Crest Wetland Restoration As-built Report Emerald Crest Board November 22, 2017 Page 2 plantings are not warranted, as increasing the density beyond four feet on-center would be detrimental to the survival of individual plantings and would not improve the ability of the site to achieve the goals and performance standards stated in the approved plan. The installed plant totals in Table 1, below, should be used to gauge whether the site has achieved the applicable survival standards for years one and two. All of the installed trees and shrubs appeared healthy at the time of installation. The hydroseed mix had been applied per plans, the grasses, sedges, and rushes had germinated, and the seedlings were actively growing at the time of the as-built inspection. Table 1: Plant Installation Quantities Species Common Name Quantity Installed Plan Quantity Fraxinus latifolia Oregon ash 20 20 Cornus sericea Red-osier dogwood 52 55 Physocarpus capitatus Pacific ninebark 36 55 Rosa nootkana Nootka rose 40 55 Rubus spectabilis Salmonberry 37 55 Lonicera involucrata Black twinberry 51 55 Salix spp. (live stakes) Willow 129 180 Atherium filix-femina Lady fern 43 90 Total 408 565 The woodchip mulch has been installed around each of the installed plants at the required thickness and diameter. While not stipulated in the approved plan, the landscape contractor incorporated organic compost into the soil. This pro-active step will improve the establishment and growth rates for the installed vegetation. A temporary, above-ground irrigation system has been installed per plan. The split-rail fence and Native Growth Protection Area signs have also been installed per plan. The silt fence installed during construction has been removed per a request from Watershed staff. Two permanent monitoring transects were installed during the as-built inspection. Due to the configuration of the site, the monitoring transects could not be established at equal lengths. Transect 1 is 100-feet-long, and Transect 2 is 75-feet-long. Native and invasive vegetation coverage will be measured along these transects during future Emerald Crest Wetland Restoration As-built Report Emerald Crest Board November 22, 2017 Page 3 monitoring inspections. The results for each transect shall be weighted to achieve a site- wide average. A total of four photopoints were established at representative locations around the site. These photopoints will be duplicated at all future monitoring inspections. See as-built photopoints below. With the successful installation of the plants specified on the restoration plan at the restoration site, we recommend that the construction phase be considered complete and the monitoring phase commence. The monitoring program requires five years of monitoring, post-installation. Annual performance monitoring is to be conducted in the late summer or early fall beginning in 2018. Spring maintenance inspections will commence in the spring of 2018. Please call if you have any questions or if we can provide you with any additional information. Sincerely, Ryan Kahlo, PWS Senior Ecologist Photopoint 1 Photopoint 2 Photopoint 3 Photopoint 4       50'50'HOUSEHOUSEPARKINGDRIVEWAYWETLANDCATEGORY IV50' BUFFEREXISTING FEATURESWETLAND BOUNDARY, APPROX. (NOT SURVEYED)APPROXIMATE WETLAND BUFFERTESC AND DEMOLITION LEGENDSPLIT RAIL FENCE WITH CRITICAL AREA SIGNTREESOREGEON ASH / FRAXINUS LATIFOLIASHRUBSCORNUS SERICEA / REDTWIG DOGWODLONICERA INVOLUCRATA / TWINBERRYPHYSOCARPUS CAPITATUS / PACIFIC NINEBARKROSA NUTKANA / NOOTKA ROSERUBUS SPECTABILIS / SALMONBERRYLIVE STAKES & GROUNDCOVERSALIX LASIANDRA / PACIFIC WILLOWATHYRIUM FILIX-FEMINA / LADY FERNSALIX SCOULERIANA / SCOULER'S WILLOWHYDROSEED MIXAMERICAN SLOUGHGRASS / BECKMANNIA SYZIGACHNE 45%WESTERN MANNAGRASS / GLYCERIA OCCIDENTALIS 45%SPREADING RUSH / JUNCUS PATENS 5%SLOUGH SEDGE / CAREX OBNUPTA 5%QTY2052513640376543653.5 LBS45%45%5%5%SPACING10' O.C.4' O.C.4' O.C.4' O.C.4' O.C.4' O.C.4' O.C.4' O.C.4' O.C.SIZE2 GAL.1 GAL.1 GAL.1 GAL.1 GAL.1 GAL.3' MIN.4 IN'3' MIN.NOTEALL SHRUBS TO BEFULL AND WELLROOTEDONLY PLANT WITHINBUFFER IMPACT AREAAPPLY TO ENTIREPLANTING AREAcoseruspphcarnloin20.00'20.00'PLANT SCHEDULEPLANTING TYPICALcosecosecosecosecoseloinloinloinloinloinphcaphcaphcaphcaphcarnrnrnrnrnrusprusprusprusprusp3,827 SQUARE FEETfrlafrlafrlaPROJECT MANAGER: DESIGNED: DRAFTED: CHECKED:SHEET SIZE:ORIGINAL PLAN IS 22" x 34".SCALE ACCORDINGLY.BY© Copyright- The Watershed CompanyDATE PRINTED BY FILENAME THEWATERSHEDCOMPANYS c i e n c e & D e s i g n750 Sixth Street SouthKirkland WA 98033p 425.822.5242www.watershedco.comJOB NUMBER:SHEET NUMBER:SUBMITTALS & REVISIONS DESCRIPTIONDATENO. EMERALD CREST WETLAND RESTORATION PLAN PREPARED FOR ANGIE BRINGIER EMERALD CREST HOA PARCEL #: 2329780000 RENTON, WA 98058RKKMB / LVLVRK / MSF160707OF 51 11-21-16 REVIEW SET KMB 2 02-01-17 CITY COMMENTS KMB 2/6/2017 KYLE BRAUN 160707_EMERALD_CREST_MITIGATION.DWGPLANTING AND RESTORATION AS-BUILT PLANW340'10'5'020'LEGEND1W318" MIN. 4"12"12" 3'-0" 6" 12"8'-0" MAX4"CHAMFER TOP OFPOSTS 45 DEGREES TOA DEPTH OF 1" ON ALLFOUR SIDES.ATTACH CITY/COUNTYAPPROVED PRE-PRINTEDMETAL SIGN TO POST WITHTWO 58" DIA. GALVANIZEDCARRIAGE BOLTS. SEE PLANSFOR SIGN LOCATIONS.FINISHED GRADECOMPACTED GRAVEL BASE.NO CONCRETE IS TO BEPLACED IN SENSITIVE AREAS.COMPACTED SUBGRADE6" x 6" ROUGH CUT, SPLIT, CEDARPOST NOTCHED TO CONTAINAND CONCEAL RAIL CONNECTION2 X 6 ROUGH CUT, SPLIT,CEDAR RAILSScale: NTSSPLIT RAIL FENCE WITH CRITICAL AREA SIGN1SCALE 1:10