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V-12-33 Main Application Materials - reduced.pdf1-1 ARCHITECTURAL DEsiGN Reit; COMPREHEWSWE PLAN AMENDMENT 1 1 CONDITIONAL USP PI,RMIT FILE 9 ZONE 2— D HOME OCUWATION DATE RiCDBY o n, il eE— FORMAL SUBDIVISION 1 SHORTSUBDIVISION FEE cS RE CEI PT 4 LOT LINE ADflJSTMENT HEARiNG DATE r! PLANNED RLSIDFNTIAL Dim.'LOPMENT M OFFICIAL STRE.ETMAP AMENDMENT Y,,HE 17 STAFT 71 PB D ADB 1-1 cc 7 STR& E'rVACA FI ON I REZONE l"I SHORELINE PLRmI'r VARIANCE / REASONABLE USE EXCEPTION OTHER: V Ck V j (A YI cr- C 2-) 7' PROPERTY ADDRESS OR LOCATION L L L✓ i L2-, PROJECT NAME (Ir APPLICABLE) 'k /U PROPERTY OWNER -7 t11 PHONE d ArmkEss .7",, Z E-MAIL___a �I �",-�FAX TAX ACCOUNT# -7 SEC, Twp. —)T RNG. DESCRIPTION OFTROJECT OR PROPOSED Us r. (ATFACI I COV E.'R LEITER AS NECESSARY 0 DE�SCI PROJF�CTMEETS AlIPUCABLE CODF.S (ATTACH COVER LETTER AS NECF.SSARY) "i �AJ APPLICANT PHONE # ADDRESS E-MAILFAX 4 CONTACT PERSON/AG ENT PHONE# ADDRESS E-MAIL FAX 9 The widersigned applicant, and hisJher/fts heirs, and assigns, in consideration on the processing of the application agrees to 'release, indemnify, defend and hold the City of Ednionds harmless fi-oni any and ail damages, including reasonable attorney's fees, arising from any action or infraction based in whole or part upon false, misleading, inaccurate or incomplete information fornished by the applicant, his/her/its agents or employees. By my signature, I certify that the information and exhibits herewith submitted are true and correct to the best of rny knowledge and that I am authorized to file this application on the behaff ofthe owner as fisted below. SIGNATUREOF APPLICAN r/AGENT DAT E, Property Owners Authorization certify under the penalty of pekgury under the laws of the State of Washington that the following is a true and correct statement: I have authorized the above AppHcant/Agent to apply for the subject land use application, and grant my permission for the public officials and the staff of the City of Editionds to enter the subject property for the purposes of inspection and posting attendant to this application. SIGNATURE OF OWNER DATE Questions? Call (425) 771-0220, Revised on 9,114110 B - Land I.JseApphca�.iamdirx Page I of PROJECT: HILLIVIAN RESIDENCE 1139 SIERRA PLACE EDMONDS WA 980'20 OWN EIRIAPP Ll IT: TOM & LIN HILLMAN 15915 74' TH ISLW EDM,ONDS'VVA 98026 425-745-4669 . . ......... DEVE-LOPMENT SERVICES PROJECT'S New single farnHy residence on a shy acre lot with critical areas (type Np stream, catlegoty 3 wetland, moderate -to -steep slope) 1Site, and Floor Plains and Elevations by OwnerAppli cant Ma'y-Ame 2012 �2,, Critical Area Study and Wetiand Kfigation Plan, WetIland Resources, Inc,,, Project #11033 September 21, 2,011, revised July 18, 2012 1 Geotech6cal Engineering Study Earth Solutions NW, LLC, Project #E,S-,23 May 9, 2012, revised jWy'16, 2012 4, Patlial Topographic Survey Lovell-,Sauerland & Associates, Inc., File No. 5354-0-12 March 1, 2012, revised July 1, 2012' 5. Civil (Grading anid Drainage) Plan Donna Rregke, P.E Juri�e 25, 20,12 A variance is hereby requested for the folilowing sections of the Edmonds Community Dievelopmen,t Code, (ECDC)� 1 A, 23,,WQ40,Fjc� C Wetland Buffer, Reducti"On This section requires a 50 -foot buffer, for a category 3 wetland.. The applicant requests reduction of fts, buffer to zero on the western boundary of the wetland, and proposes liffiffiall Varkuwc K"Juest fly 2012 partial encroachment into 11 % of the wetland itself, with compensatory mitigation measures. 1 B. 23.50.040.F8c: Stormwater Management Facilities Location This section requires that stormwater outfalls, pipes and conveyance systems only be allowed in the outer 25% of a Category 3 wetland buffer, provided that no other location is feasible and that the wetland's functions and values will not be degraded. The applicant requests the storm drainage system be placed in the buffer in close proximity to the existing wetland edge, and proposes compensatory mitigation measures. 1C. 23.50.05011c: Category 3 Wetland Replacement Ratio Reduction This section requires that category 3 wetlands which are eliminated be mitigated by replacing them at a 2:1 ratio. The applicant requests that this requirement be reduced to zero, and proposes compensatory mitigation measures. 2. 23.90.040.D1: Type Np Stream Buffer Reduction. This section requires a 50 -foot buffer for a type Np stream, reducible by 50% per Section 23.90.040.D2. The applicant requests a 25 -foot stream buffer and proposes stream buffer enchancement measures. 3. 23.40.280: Critical Area Building Setback Reduction This section requires a 15 -foot building setback from critical areas/buffers. The applicant requests a reduction to 5' at the wetland edge, and 3' at the stream buffer edge, in order to allow a larger portion of these areas to remain intact. 4. 16.20.030: Front Yard (Street Front) Setback Reduction. This section requires a 25 -foot front yard (street front) setback for properties with an RS -12 zoning designation. The applicant requests a reduction to a 12 -foot front yard setback in order to maximize distance from the stream. VARIANCE CRITERIA PER ECDC 20.85 (ZONING): 1. SPECIAL CIRCUMSTANCES The special circumstances affecting this property consist of multiple critical areas, including a category 3 wetland covering roughly the middle third of the site, a type Np stream running across the rear of the parcel, and a moderate -to -steep slope covering approximately the eastern third of the lot. The ECDC provisions limit the placement of a new single family home to that portion of the lot outside the 50 -foot wetland buffers. The only part of the property that is not either wetland or buffer is the eastern fifth of the lot, which has the steepest slope. However, providing vehicular access to this area from the street would require over 200 linear feet of driveway passing through both western and eastern buffers, as well as Hillman Variance Request 2 July 2012 through the entire width of the wetland itself. Driveway slopes would exceed 18%, involving significant grading disturbance of the wetland and its buffers, as well as significant retaining structures for cuts and fills. This is not the least disruptive option for development of the property; the current proposal placing the house in the southwest corner of the lot causes much less disturbance. The applicant proposes to place the house in the western buffer, with only the access driveway, garage and backyard encroaching partially into the wetland. The code requires a 2:1 replacement ratio for wetlands that have been eliminated. However, due to the steepness of the slopes on the property and other factors, Wetland Resources, Inc. (WRI) recommends against wetland creation in favor of wetland enhancement (as discussed in their referenced study). The code also limits placement of the house to that portion of the lot outside the 50 -foot stream buffers. Due to the location and shape of the stream, the only parts of the lot not in its buffers are the easternmost fifth (described above as undesirable because of the slope issue and access disturbance problem), and the small southwest corner of the property immediately adjacent to the street. This southwest corner, although inclusive of both stream and wetland buffers, was determined to be best place to locate a house that would cause the least amount of impact to the critical areas of the site. The property's geographical constraints make it impossible to place a dwelling on the site and provide access to it without obtaining a variance to the code requirements for wetlands and stream buffers. The challenge is to minimize the impacts and provide mitigation for them. The zoning code mandates a 25 -foot front yard setback for houses in the RS -12 zone. Adhering to this requirement would push the proposed residence closer to the stream, necessitating a further reduction in the proposed stream buffer. There is basically a trade-off between stream buffer and front yard setback, with the building pad sandwiched inbetween. Reducing the front yard setback is seen as the lesser of two evils, and at 12' it still allows for a 22' front yard (including the 10' between the front property line and the existing roadway edge). And due to the cul-de-sac configuration, it still provides for a driveway length in excess of the required 25 feet. Another consideration in proposing a 12' setback was the minimum width required to accommodate stormwater detention piping with a 5' clearance to both building and property line; this is proposed for both front and side yard setbacks. The unique combination of critical areas on this property severely limits its development. The applicant has investigated numerous design scenarios in order to come up with a reasonable proposal that both minimizes disturbance and mitigates it by enhancing the remaining portions of the property. The proposed design places the house in the western wetland buffer, with a small portion encroaching into the western edge of the wetland itself. The proposed mitigating enhancements include removal of invasive species and increasing native plant densities in the almost 90% of the wetland that remains, as well as in the remaining wetland and stream buffer area to the west of the wetland. Hillman Variance Request July 2012 The site investigation has included input and recommendations from professional wetland and geotechnical consultants, as well as a surveyor and civil engineer, plus the city's planning and engineering staff in order to produce an optimal design that takes all the factors affecting this complex site into account, and balances the competing critical area restraints to the greatest extent possible. Special attention has been paid to keeping existing site drainage patterns predominantly intact. On-site stormwater that currently runs over and through existing ground surfaces to drain downhill to the stream will be partially captured into footing drains that will discharge to the stream with less potential for erosion. New impermeable roof and driveway surfaces will have their stormwater collected to detention piping under the front and side yards, before outfalling into the stream. Infiltration measures were reviewed as a possibility for dealing with stormwater, but determined to be inappropriate for this site due to the shallowness of permeable soils as a result of a high glacial till layer as discussed in the referenced geotechnical study. Possible discharge to a storm drain on the other side of Sierra Place was also considereded, but eliminated due to its location under heavily landscaped neighboring yards and the high elevation of the existing catch basin. The applicant further proposes to provide special attention to critical area issues during construction, including on-site field monitoring of all earthwork by both the geotechnical and civil engineers to address drainage issues and provide additional recommendations as needed throughout the project. 2. SPECIAL PRIVILEGE Granting of this variance would not constitute special privilege, as it only enables the applicant to place a moderate single family dwelling on a lot zoned for this purpose. The applicant's proposed home is smaller than the smallest home of all the properties adjoining it as shown in the comparison in Table 3 in the WRI study. If no variance was granted, the applicant would be denied the use of property enjoyed by the neighbors in the same zoning district. 3. COMPREHENSIVE PLAN The single family home proposed for this property is consistent with its comprehensive plan map designation of "Single Family Resource", with goals stated as promoting "high quality residential development... balancing economic and aesthetic considerations". The applicant's design fulfills the comprehensive plan's priorities of harmonizing with existing surroundings (by use of similar style and building materials), minimizing view encroachments and protecting privacy (by building on the lowest portion of the parcel and away from neighboring homes' windows and yards), and providing compatibility with the various natural constraints of the site (reducing disturbance of existing conditions to a minimum level). Hillman Variance Request July 2012 4. ZONING ORDINANCE The proposed single family home is consistent with the RS -12 zoning designation. Based on the large lot size, greater density would normally be allowed, but due to the critical area restraints, one dwelling is a more appropriate use of the property. Although reductions of front yard and critical area setbacks are requested, the remainder of the zoning code has been followed, including rear and side yard setbacks, minimum driveway length and building height limit. 5. NOT DETRIMENTAL The proposed design poses no more of a detriment to the public health, safety and welfare than any other normal single family residence, nor does it injure or harm the neighbors or their properties. This project will likely improve the neighboring properties' territorial views by virtue of the proposed enhancement of the existing wetland by means of the clearing of invasive vegetation and the introduction of additional landscaping in the form of new native species plantings (per the WRI study). 6. MINIMUM VARIANCE Without this variance, the applicants would be denied construction of any reasonable home on this property. Strict adherence to the ECDC provisions cited earlier would make the lot essentially unbuildable due to overlapping critical areas. Denial of any one of the requested variance items would reduce the buildable portion of the parcel to an unreasonable level. Hillman Variance Request July 2012 VARIANCE CRITERIA PER ECDC 23.40.210 (CRITICAL AREAS): Code section 23.40.210.A2's general criteria (items a. through g.) are addressed on pages 7 and 8 of the WRI study, paraphrased herein as follows: a. DENIAL OF REASONABLE ECONOMIC USE The on-site wetland, stream and associated buffers occupy about 78% of the subject property. Because of this, strict application of the standards set forth in Title 23 would prohibit a reasonable development on the site. b. NO OTHER REASONABLE ECONOMIC USE HAS LESS IMPACT This property is zoned RS -12 with a "Single Family Resource" comprehensive plan designation. There is no reasonable use for the site other than single family residential that would result in less impact to the critical areas. C. MINIMUM NECESSARY IMPACT The applicant has carefully considered the house size and design in order to minimize critical area impacts. The total footprint and living space are the smallest of all of the adjoining properties. The research and design work clearly demonstrate that the proposed development is the minimum necessary to achieve a reasonable economic use of the property. d. NOT CAUSED BY THE APPLICANT No actions by the applicant have resulted in the inability to derive reasonable economic use of the site. There are no outstanding violations, boundary line adjustments or like impediments to development. There are no existing structures on the lot. All obstacles to reasonable economic use come from the critical area requirements of the ECDC, resulting in the need for this variance. e. NO THREATS TO PUBLIC HEALTH SAFETY OR WELFARE The proposed development will not be hazardous to public health, safety or welfare. The project has been carefully designed to minimize site impacts to the greatest extent possible. It will not affect water quality or create flooding issues in downstream systems, nor cause erosion or tree hazards for neighboring properties. f. MINIMIZED LOSS OF CRITICAL AREA FUNCTIONS AND VALUES The proposal has been carefully designed to minimize net loss of on-site functions. A watershed approach to protection and mitigation design has been considered as part of the proposed mitigation measures. g. CONSISTENT WITH OTHER REGULATIONS AND STANDARDS All other pertinent regulations and design standards are being applied as part of this application. Hillman Variance Request July 2012 Code section 23.40.21 0.13's specific criteria (items 1. through 6.) are addressed below. 1. PECULIAR TO THE LAND The special conditions and circumstances necessitating this variance are the property's critical area features. Other lots in the area do not have the unique combination of wetland, stream and slope that make this parcel such a challenge to develop. 2. NOT CAUSED BY THE APPLICANT The critical areas on the parcel are existing natural geographical features not resulting from actions by the applicant. 3. MINIMUM NECESSARY VARIANCE FOR REASONABLE ECONOMIC USE Due to the predominance of the site's critical areas, it is not possible to place a dwelling on the lot and provide access to it without a variance to the code requirements for wetlands and stream buffers. The buffer/setback reductions requested herein are the minimum necessary to allow a modest -sized house to be placed on the property in the only location where it makes sense to develop. The applicant is not proposing to build anything more than a reasonable single family home in keeping with what the neighboring properties have. 4. NO SPECIAL PRIVILEGE Granting this variance will only allow the applicant to build a modest single family home on the southwest corner of this lot. No other privileges will be provided. 5. CONSISTENT WITH TITLE. NOT DETRIMENTAL Granting this variance is consistent with the purpose and intent of Title 23 to protect critical areas from degradation of functions and values. The proposed project will mitigate its impacts to the critical areas by means of enhancement and protection of remaining wetland and buffer portions of the lot. As previously stated, the project is not materially detrimental to public health, safety or welfare, nor injurious to the neighbors or their properties. 6. BEST AVAILABLE SCIENCE In accordance with ECDC 23.40.310, the WRI study prepared for this project has made use of the best local, regional and national tools available to classify, analyze and propose protective mitigation measures to maintain beneficial functions for the critical areas on this property. The stream on the site is non-fishbearing, type Np. SUMMARY The requested variance will allow the applicant to develop a modest single family home on a difficult site that would not otherwise be buildable. The applicant has worked with a qualified wetland biologist to determine the least detrimental method of developing the property in terms of minimizing wetland, stream and buffer disturbance and enhancing remaining wetland and buffer areas. The applicant has invested in a geotechnical study, survey and civil engineering to assist in optimizing the design and creating an overall plan that represents an improvement to the existing condition. Hillman Variance Request 7 July 2012 F LLJ IL V) 3: 0 9,1 LJ Z LLJ —.1 ki S§ 6R F gI I F 0 w NJ V5 LLJ sn cv C= C14 0) Lill s < U A, , 14 t .... LZ— Sit, - - - - - - - - - - - - - - - - - - --- - - ceI L (if .1V U, Lvo - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - �-P Zi 3nN3AV QldVIAIO HO _1 A A Z�r 1'm V-1 0 --- 1 1 11 C -t HAA 3OV-1d V88DS rolz IN 10 =�LIZ) IU �IONBCS:3;84 YYTI H nm g npa sv:E-lvns - i C) U) co co 0 z < 0 co E LIJ f%40 LU LL. 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Contributing waters include runoff from upslope properties as well as spring water originating on the site itself. The stream is part of the city's existing stormwater system. The proposed single-family home for the property is located in the southwest corner of the site, where it will not interfere with the natural flow pattern of the upslope portions of the lot; the bulk of the site will remain undisturbed and continue to drain towards the stream in the present manner. The runoff from the new impervious roof and driveway surfaces (as well as a small area of porch) will be collected via a tightlined drain system to the proposed stormwater detention pipe at the westernmost edge of the lot, and will discharge at a dispersion outfall at the stream edge. A footing drain behind the proposed retaining wall at the proposed wetland boundary will also discharge via the stormwater detention outfall pipe at the western edge of the wetland/stream buffer north of the house. The proposed drainage system results in the site's waters being delivered to the stream, similarly to the present pre -development condition, but with the additional protection provided by detention of the new roof and driveway runoff. #8: Wetland Protection This requirement applies to projects that include using wetlands as part of the stormwater detention system. The present project does not. None of the stormwater collected from the proposed new impervious surfaces will be discharged into the wetland. The stormwater collected from the proposed new impervious surfaces is tightlined to a detention pipe and remains contained until its discharge at the stream outfall location. 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P. -7 77, col i ��\ % W CN CL n 0 !N L T yn 7-' re L W 0 LJ C5 z cn C'41 WAVE", A10 -10,4q. 01111am I LINE I IN 11 jif-1121 May 9, 2012 . . ......... Stophen H. Avril Staff Geologist a Raymond A. Coglas, PX princilpal REVISED GEOTECHNICAL ENGINEERING STUDY 1139, SIERRA, PLACE EDMIONDS, WASHINGTON AMEM Earth Solutions NW, LLC 1806 - 1316t�' Place, Northeast, Suite 201 Bellevue, Washington 98006 Ph. 425-4494704 F'ax. 426-4494711 Tolit Free: 866-336-8710 RECEIVED DEVEL-01VEN ISIJOAC'0`1� GOI)NIT141 r1i Dow, MEW, smvilosm c Geolechnical Engineeping Repopt Geotechnical Services Are Performed for Specific Purposes, Persons, and Projects Geotechnical engineers structure their services to meet the specific needs of their clients. A geotechnical engineering study conducted for a civil engi- neer may not fulfill the needs of a construction contractor or even another civil engineer. Because each geotechnical engineering study is unique, each geotechnical engineering report is unique, prepared solelyfor the client. No one except you should rely on your geotechnical engineering report without first conferring with the geotechnical engineer who prepared it. And no one —notevenyou—should apply the report for any purpose or project except the one originally contemplated. Read the Full Report Serious problems have occurred because those relying on a geotechnical engineering report did not read it all. Do not rely on an executive summary. Do not read selected elements only. A Geotechnical Engineering Report Is Based on A Unique Set of Project -Specific Factors Geotechnical engineers consider a number of unique, project -specific fac- tors when establishing the scope of a study. Typical factors include: the client's goals, objectives, and risk management preferences; the general nature of the structure involved, its size, and configuration; the location of the structure on the site; and other planned or existing site improvements, such as access roads, parking lots, and underground utilities. Unless the geotechnical engineer who conducted the study specifically indicates oth- erwise, do not rely on a geotechnical engineering report that was: • not prepared for you, • not prepared for your project, • not prepared for the specific site explored, or • completed before important project changes were made. Typical changes that can erode the reliability of an existing geotechnical engineering report include those that affect: • the function of the proposed structure, as when it's changed from a parking garage to an office building, or from a light industrial plant to a refrigerated warehouse, • elevation, configuration, location, orientation, or weight of the proposed structure, • composition of the design team, or • project ownership. As a general rule, always inform your geotechnical engineer of project changes—even minor ones—and request an assessment of their impact. Geotechnical engineers cannot accept responsibility or liability for problems that occur because their reports do not consider developments of which they were not informed. Subsurface Conditions Can Change A geotechnical engineering report is based on conditions that existed at the time the study was performed. Do not rely on a geotechnical engineer- ing report whose adequacy may have been affected by: the passage of time; by man-made events, such as construction on or adjacent to the site; or by natural events, such as floods, earthquakes, or groundwater fluctua- tions. Always contact the geotechnical engineer before applying the report to determine if it is still reliable. A minor amount of additional testing or analysis could prevent major problems. Most Geotechnical Findings Are Professional Opinions Site exploration identifies subsurface conditions only at those points where subsurface tests are conducted or samples are taken. Geotechnical engi- neers review field and laboratory data and then apply their professional judgment to render an opinion about subsurface conditions throughout the site. Actual subsurface conditions may differ—sometimes significantly— from those indicated in your report. Retaining the geotechnical engineer who developed your report to provide construction observation is the most effective method of managing the risks associated with unanticipated conditions. A Report's Recommendations Are Not Final Do not overrely on the construction recommendations included in your report. Those recommendations are not final, because geotechnical engi- neers develop them principally from judgment and opinion. Geotechnical engineers can finalize their recommendations only by observing actual subsurface conditions revealed during construction. The geotechnical engineer who developed your reportt cannot assume responsibility or liability for the report's recommendations if that engineer does not perform construction observation. A Geotechnical Engineeping Report Is Subject to Misinterpretation Other design team members' misinterpretation of geotechnical engineering reports has resulted in costly problems. Lower that risk by having your geo- technical engineer confer with appropriate members of the design team after submitting the report. Also retain your geotechnical engineer to review perti- nent elements of the design team's plans and specifications. Contractors can also misinterpret a geotechnical engineering report. Reduce that risk by having your geotechnical engineer participate in prebid and preconstruction conferences, and by providing construction observation. Do Not Redraw the Engineer's Logs Geotechnical engineers prepare final boring and testing logs based upon their interpretation of field logs and laboratory data. To prevent errors or omissions, the logs included in a geotechnical engineering report should never be redrawn for inclusion in architectural or other design drawings. Only photographic or electronic reproduction is acceptable, but recognize that separating logs from the report can elevate risk. Give Contractors a Complete Report and Guidance Some owners and design professionals mistakenly believe they can make contractors liable for unanticipated subsurface conditions by limiting what they provide for bid preparation. To help prevent costly problems, give con- tractors the complete geotechnical engineering report, but preface it with a clearly written letter of transmittal. In that letter, advise contractors that the report was not prepared for purposes of bid development and that the report's accuracy is limited; encourage them to confer with the geotechnical engineer who prepared the report (a modest fee may be required) and/or to conduct additional study to obtain the specific types of information they need or prefer. A prebid conference can also be valuable. Be sure contrac- tors have sufficient Ameto perform additional study. Only then might you be in a position to give contractors the best information available to you, while requiring them to at least share some of the financial responsibilities stemming from unanticipated conditions. Read Responsibility Provisions Closely Some clients, design professionals, and contractors do not recognize that geotechnical engineering is far less exact than other engineering disci- plines. This lack of understanding has created unrealistic expectations that have led to disappointments, claims, and disputes. To help reduce the risk of such outcomes, geotechnical engineers commonly include a variety of explanatory provisions in their reports. Sometimes labeled "limitations" many of these provisions indicate where geotechnical engineers' responsi- bilities begin and end, to help others recognize their own responsibilities and risks. Read these provisions closely. Ask questions. Your geotechnical engineer should respond fully and frankly. Geoenvironmental Concerns Are Not Covered The equipment, techniques, and personnel used to perform a geoenviron- mental study differ significantly from those used to perform a geotechnical study. For that reason, a geotechnical engineering report does not usually relate any geoenvironmental findings, conclusions, or recommendations; e.g., about the likelihood of encountering underground storage tanks or regulated contaminants. Unanticipated environmentalproblems have led to numerous project failures. If you have not yet obtained your own geoen- vironmental information, ask your geotechnical consultant for risk man- agement guidance. Do not rely on an environmental report prepared for someone else. Obtain Professional Assistance To Deal with Mold Diverse strategies can be applied during building design, construction, operation, and maintenance to prevent significant amounts of mold from growing on indoor surfaces. To be effective, all such strategies should be devised for the express purpose of mold prevention, integrated into a com- prehensive plan, and executed with diligent oversight by a professional mold prevention consultant. Because just a small amount of water or moisture can lead to the development of severe mold infestations, a num- ber of mold prevention strategies focus on keeping building surfaces dry. While groundwater, water infiltration, and similar issues may have been addressed as part of the geotechnical engineering study whose findings are conveyed in -this report, the geotechnical engineer in charge of this project is not a mold prevention consultant; none of the services per- formed in connection with the geotechnical engineer's study were designed or conducted for the purpose of mold preven- tion. Proper implementation of the recommendations conveyed in this report will not of itself he sufficient to prevent mold from growing in or on the structure involved. Rely, on Your ASFE-Member Geotechncial Engmeer for Additional Assistance Membership in ASFE/The Best People on Earth exposes geotechnical engineers to a wide array of risk management techniques that can be of genuine benefit for everyone involved with a construction project. Confer with you ASFE-member geotechnical engineer for more information. A11111116w__ WSWREM The Baal People on Earth 8811 Colesville Road/Suite G106, Silver Spring, MD 20910 Telephone: 301/565-2733 Facsimile: 301/589-2017 e-mail: info®asfe.org www.asfe.org Copyright 2004 by ASFE, Inc. Duplication, reproduction, or copying of this document, in whole or in part, by any means whatsoever, is strictly prohibited, except with ASFVs specific written permission. Excerpting, quoting, or otherwise extracting wording from this document is permitted only with the express written permission ofASFE, and only for purposes of scholarly research or book review. Only members of ASFE may use this document as a complement to or as an element of a geotechnical engineering report. Any other firm, individual, or other entity that so uses this document without being an ASFE member could be committing negligent or intentional (fraudulent) misrepresentation. IIGER06045.0M May 9, 2012 Revised July 16, 2012 ES -2348 Tom and Lin Hillman 159815 - 74th Place West Edmonds, Washington 9802 Dear Mr. and Mrs. Hillman: H;![[[:�[ Earth Solutions NW LLC ® Geotechnical Engineering ® Construction Monitoring • Environmental Sciences Earth Solutions NW, LLC (ESNW) is pleased to present this report titled "Geotechnical Engineering Study, Proposed Single -Family Residence, 1139 Sierra Place, Edmonds Washington. Based on the results of our study, construction of the proposed residence as planned is feasible from a geotechnical standpoint. Based on our field exploration, and review of the test pit logs prepared by Associated Earth Sciences, Inc. (AESI), the native soils underlying the proposed residence consist primarily of medium dense to very dense glacial till deposits. Moderately heavy groundwater seepage was observed during our field exploration (April 2012) at test locations HH -1 and HH -2. The groundwater was encountered at depths between one and three feet. Geotechnical recommendations for the foundation design and other pertinent geotechnical considerations are provided in this study. The opportunity to be of service to you is appreciated. If you have any questions regarding the content of this Geotechnical Engineering Study, please call. Sincerely, EARTH SOLUTIONS NW, LLC Stephen H. Avrii Staff Geologist Earth Solutions NW, LLC 1805 - 136th Place N.E., Suite 201 0 Bellevue, WA 98005 0 (425) 449-4704 0 FAX (425) 449-4711 TABLE OF CONTENTS ES -2348 PAGE INTRODUCTION........................................................................ 1 General.......................................................................... 1 Proiect Description........................................................... 1 SITECONDITIONS..................................................................... Surface........................................................................... 2 Subsurface...................................................................... 2 Geologic Map and Soil Review .................................. 2 Groundwater..................................................................... 3 CRITICAL AREAS AND GEOLOGIC HAZARDOUS AREAS ASSESSMENT..................................................................................... 3 Site and Construction Plans ........................................................ 3 Assessment of Geological Characteristics ................................ 3 Landslide Hazards.............................................................. 3 ErosionHazards................................................................. 4 Minimal Critical Area Buffer and Setback ............................. 4 DISCUSSION AND RECOMMENDATIONS ....................................... 4 General............................................................................. Site Preparation and Earthwork ............................................ 5 Temporary Erosion Control ....................................... 5 Excavation................................................................. 5 Structural Fill Placement ........................................... 5 Slope Fill Placement ................................................. 6 Excavations and Slopes ................................................... 6 Utility Support and Trench Backfill ...................................... 6 Foundations. ............................ Seismic Considerations......................................................... 7 Slab -on -Grade Floors......................................................... 7 Cast -In -Place Retaining Walls ............................................. 7 Drainage........................................................................... 8 LIMITATIONS............................... ............................................... Additional Services............................................................ 9 Earth Solutions NW, LLC GRAPHICS PLATE 1 PLATE 2 PLATE 3 PLATE 4 PLATE 5 APPENDICES TABLE OF CONTENTS Cont'd ES -2348 VICINITY MAP HAND HOLE LOCATION PLAN SLOPE FILL PLACEMENT DETAIL RETAINING WALL DRAINAGE DETAIL FOOTING DRAIN DETAIL Appendix A Subsurface Exploration Hand Hole Logs Test Pit Logs (Associated Earth Sciences, Inc.) Appendix B Laboratory Test Results Earth Solutions NW, LLC REVISED GEOTECHNICAL ENGINEERING STUDY PROPOSED SINGLE-FAMILY RESIDENCE 1139 SIERRA PLACE EDMONDS, WASHINGTON ES -2348 INTRODUCTION General This Geotechnical Engineering Study was prepared for the proposed single-family residence to be constructed on the north side of the cul-de-sac which forms the eastern terminus of Sierra Place in Edmonds, Washington (see Vicinity Map, Plate 1). The purpose of this study was to prepare geotechnical recommendations for the proposed development. Our scope of services for completing this Geotechnical Engineering Study included the following: • Reviewing past subsurface information conducted by Associated Earth Sciences, Inc., for the property located at 1142 Sierra Place in Edmonds, Washington; • Subsurface exploration, laboratory testing, engineering analysis, and; • Preparation of this report. As part of our report preparation, pertinent sections of the following documents were reviewed: • Preliminary Drainage Diagram prepared by Tom and Lin Hillman; • The Geologic Map of the Edmonds East and Part of the Edmonds West Quadrangles, USGS Map MF -1541; • Subsurface Exploration, Geologic Hazard, and Preliminary Geotechnical Engineering Report, Proposed Edmonds Residence, completed by AESI, project No. EE07659A, dated January 25, 2008; • The USDA Soil Conservation Survey (SCS) of Snohomish County, and; • City of Edmonds Geologically Hazardous Areas (Chapter 23.80). Proiect Description The site is located off the northern side of the east terminus of Sierra Place and near the top of a descending natural slope. The project site is a currently undeveloped. The proposal includes construction of a two-story single-family residence and associated improvements. The building construction will consist of relatively light wood -framing and conventional foundations. Perimeter and interior continuous footing loads are estimated to be on the order of 1 to 2 kips per lineal foot. Slab loading is estimated to be on the order of 150 pounds per square foot. Earth Solutions NW, LLC Tom and Lin Hillman May 9, 2012 Revised July 16, 2012 ES -2348 Page 2 We anticipate footings will follow the existing grade to the extent practical in order to minimize disturbance. The maximum cuts for the proposed structure foundations will be on the order of six feet. A series of concrete retaining walls will be utilized for support of the proposed cuts at the east side of the residential structure adjacent to the wetland. The currently proposed footprint for the new residence is approximately illustrated on Plate 2 of this study. If the above design assumptions are incorrect or change, ESNW should be contacted to review the recommendations in this report. ESNW should review the final design to verify that our geotechnical recommendations have been incorporated into the design. SITE CONDITIONS Surface The site is located on the north side of the east terminus of Sierra Place in Edmonds, Washington. The approximate location of the subject property is illustrated on the Vicinity Map (Plate 1). The property consists of a single tax parcel approximately 0.93 acres in size. The approximate limits of the property are illustrated on the Hand Hole Location Plan (Plate 2). The site consists of a roughly rectangular lot which is situated near the crest of a slope with a local high elevation of about 280 feet. The topography across the lot generally descends to the west with about 68 feet of total elevation change. The site is vacant and vegetated with a relatively mature forest of fir and cedar trees. Subsurface The approximate locations of the hand holes are illustrated on the Hand Hole Location Plan (Plate 2). The hand hole logs are provided in Appendix A. An ESNW representative observed, logged and sampled four test excavations using hand tools extending to depths of four feet below existing grades (April 2012). The eastern upslope portion of the site was explored during preparation of the referenced report prepared by AESI by excavating test pits to depths of approximately 14 feet. The following is a general description of the soil conditions encountered at the test sites. In general the lot is underlain by medium dense to dense silty sand consistent with Vashon glacial till deposits. Soil relative density generally increased with depth. Geologic Map and Soil Map Review As part of our report preparation, we reviewed available maps regarding soil conditions for the subject site. The referenced geologic map identifies glacial till deposits (Qgt) across the subject property. Earth Solutions NW, LLC ESNW encountered gyoundwater seepage duiring our subsurface explaration, ('April 2012) at a depth of two and three juarters feet at test locationHH-1� and onle: and a half feet at test location HH -2, Groundwater seepage was reported at the test IN locations during the, fieldwolrk conducted by, AssocWed Earth Sciences, Inc, (January 2008) at diepths of four and I I feet, i ion Groundwater seepage rates, fluctuate depend'hig on many factors, including precipitat' III-, urabon and intensity, the time of year,, and soil conditions., In general,, grou�ndwater seepage and flow rates aire higheir duOngi the,; wetter, Mnter months. However, zones of persistent or chronio groundwater seepagie are not uincommon:, and can be encountered during any time ot year. As part ofthis geotechnical ngineering study we reviewed the City of 'Edmonds Critical Area Ordinance (Chapter 23,80). Per the Cily of Edmonds Critical Areas Report requirements, the followng topics related, to development plans and site conditions are addressed. I Construction of' a single-farnily residence is planned for the site. 'The ma,ximurn, cuts for the proposed structure foundations will be on the order of six feet, The attached Hand Hole Location Plan (Plate 2) �Ijlustrates the proposed building footprint area and site topography, ESNW observed no signs of surfacieseeps, hummocky terrain, head scarpsi, or r0ling during our fieldwork, The overall stability of the steep slope areas can be characterized as good based on our field, observations, 4 =0 = M DO I t, It The referericed, geollfogic map identifies glacJW fill deposits across the, subjectr property, The native soils encountered at the test locations consisted primadly of miedlium dense to very dense silty sand consistent with the �geologic map designations. ESNW observed, perched groundwater, at a depth of one, arid a half to three feet duringi fieldwork. THs, condition is consistent with other till sites where, grOUrrdwater is commonly found' perchied at the contact between loose sdIty, sand topsoil arid the cemented glacial till material. With respect to landslide hazard areas, 32�.80,020 of the Edmonds City Development Code (EC.DQ defines landslide hazard areas as slopes of 40 percent or greater with a vertical rise of more than ten feet. Eaft Solutions ", LiLC Tom and Lin Hillman May 9, 2012 Revised July 16, 2012 ES -2348 Page 5 This report has been prepared for the exclusive use of Tom and Lin Hillman and their representatives. This study has been prepared in a manner consistent with the level of care and skill ordinarily exercised by other members of the profession currently practicing under similar conditions in this area. Site Preparation and Earthwork Site preparation will likely include removing existing vegetation from the construction envelope including, but not limited to trees, brush and topsoil. Temporary Erosion Control Temporary erosion control measures should include, at a minimum, silt fencing placed along the downslope perimeter of the construction envelope, and a construction entrance consisting of at least six inches of quarry spalls should be considered in order to minimize off-site soil tracking and to provide a firm surface. Surface water should not be allowed to flow over temporary or permanent slopes. Interceptor drains or swales should be considered for controlling surface water flow patterns. The geotechnical engineer should observe the erosion control measures, and provide supplement recommendations for minimizing erosion during construction, as necessary. If temporary discharge of stormwater offsite is planned during construction, turbidity monitoring should be performed, as required by the City of Edmonds. Excavations Based on the subsurface conditions described in the referenced report by AESI and our fieldwork, medium dense to dense silty sand soils are anticipated to be encountered in the planned excavations. The soils anticipated to be encountered in the proposed excavations can be characterized as having of moderate to high sensitivity to moisture. During periods of extended precipitation, or if the in-situ moisture content is over optimum, placement and compaction of the excavated soils could be difficult. The presence of localized perched groundwater seepage could be encountered in the planned excavations. The geotechnical engineer should observe the excavations, and provide supplement recommendations for drainage when necessary. Structural Fill Placement In general, areas to receive structural fill should be sufficiently stripped of organic matter and other deleterious material. The majority of the organic matter associated with trees, brush, root balls, and groundcover should be removed from the proposed fill and cut areas. Structural fill is defined as compacted soil placed in foundation, slab -on -grade, and roadway areas. Fills placed to construct permanent slopes and throughout retaining well and utility trench backfill areas are also considered structural fill. Soils placed in the building pad areas should be placed in maximum 12 -inch loose lifts and compacted to a relative compaction of 90 percent, based on the maximum dry density as determined by the Modified Proctor Method (ASTM D-1557-02). Earth Solutions NW, LLC Tom and Lin Hillman May 9, 2012 Revised July 16, 2012 ES -2348 Page 6 If the on-site soils cannot be successfully compacted, the use of an imported soil may be necessary. Imported soil intended for use as structural fill should consist of a well graded granular soil with a maximum aggregate grain size of four inches, and a moisture content that is at or near the optimum level. During wet weather conditions, imported soil intended for use as structural fill should consist of a well graded granular soil with a fines content of 5 percent or less defined as the percent passing the #200 sieve, based on the minus three-quarter inch fraction. Slope Fill Placement In general, fill placement throughout the existing sloped areas of the site is feasible, provided appropriate measures to bench and key the fill into the existing slope surfaces are utilized. General guidelines for slope fill placement are provided on Plate 3 of this report. The project geotechnical engineer should be on-site during the fill placement to assess the slope fill construction, and to provide supplement recommendations for the fill placement, as appropriate. During the construction of the fill slopes, appropriate means for compacting the slope face must be utilized. Excavations and Slopes The Federal Occupation Safety and Health Administration (OSHA) and the Washington Industrial Safety and Health Act (WISHA) provide soil classification in terms of temporary slope inclinations. The existing weathered native soil where groundwater is present is classified as Type C by OSHA/WISHA. Temporary slopes over four feet in height in Type C soils must be sloped no steeper than 1.5H:1V (Horizontal:Vertical). The undisturbed dense glacial till where no groundwater is exposed is classified as Type A. Temporary slopes over four feet in height in Type A soils must be sloped no steeper than .75H:1 V. If the recommended temporary slope inclination cannot be achieved, temporary shoring may be necessary to support excavations. The geotechnical engineer should observe temporary and permanent slopes to verify that the inclination is appropriate for the exposed soil, and to provide additional grading recommendations, as necessary. Utility Support and Trench Backfill The native soils anticipated to be exposed during utility trench excavations would include firm silty sand deposits. In general, the on-site soils observed at the test sites described in the referenced report should be suitable for use as structural backfill in the utility trench excavations, provided the soil is at or near the optimum moisture content at the time of placement and compaction. Areas of the onsite soils, however, may not be suited for utility trench backfill, and should be further evaluated by the geotechnical engineer at the time of construction. Utility trench backfill should be placed and compacted to the specifications of structural fill provided in this report, or to the applicable specifications of the City of Edmonds. Groundwater should be expected in utility trench excavations. Earth Solutions NW, LLC Tom and Lin Hillman May 9, 2012 Revised July 16, 2012 Foundations ES -2348 Page 7 In our opinion, the proposed single-family residence can be supported on conventional shallow foundations supported on competent or recompacted native soil or structural fill. We anticipate competent native soil capable of providing adequate foundation support will be encountered at foundation elevations or at depths of between two to four feet below existing grades elsewhere. Loose or otherwise unsuitable soil should be removed and replaced with structural fill. Assuming the foundations will be supported as described above, the following parameters can be used for the foundation design: • Allowable soil bearing capacity • Coefficient of friction • Passive resistance • Wind and seismic • Total settlement • Differential settlement 2,500 psf 0.40 (foundation /soil interface) 350 pcf (structural backfill) allowable one-third Increase 1.0 to 1.5 inches 0.5 to 0.75 inches A factor -of -safety of 1.5 had been included in the friction and passive resistance values. Seismic Considerations The 2009 International Building Code specifies several soil profiles that are used as a basis for seismic design of structures. Based on the soil conditions observed at the test pit locations, Site Class C, from table 1613.5.2, should be used for design. In our opinion, liquefaction susceptibility at the site can be characterized as low. The relative density of the native soil and lack of a shallow groundwater table is the primary basis for this opinion. Slab -On -Grade Floors Slab -on -grade floors should be supported on a minimum of one foot of structural fill. A capillary break consisting of a minimum of four inches of free draining crushed rock or gravel should be placed below the slab. The free draining material should have a fines content of 5 percent or less (percent passing the #200 sieve, based on the minus three-quarter inch fraction). Installation of an approved vapor barrier should be installed below the slab. The vapor barrier must be a product specifically designed for that purpose and installed in accordance with the manufacturer's specifications. Cast -In -Place Retainina Walls Retaining walls should be designed to resist earth pressures and any applicable surcharge loads. For design, the following parameters can be assumed for retaining wall design: Earth Solutions NW, LLC Tom and Lin Hillman May 9, 2012 Revised July 16, 2012 • Active earth pressure (yielding wall) • At -rest earth pressure (restrained wall) • Passive resistance • Coefficient of friction 35 pcf (equivalent fluid) 50 pcf 350 pcf (equivalent fluid) 0.40 ES -2348 Page 8 Additional surcharge loading from foundations, sloped backfill, or other loading should be included in the retaining wall design. Drainage should be provided behind retaining walls such that hydrostatic pressures do not develop. If drainage is not provided, hydrostatic pressures should be included in the wall design, as appropriate. The geotechnical engineer should review retaining wall designs to verify that appropriate earth pressure values have been incorporated into design and to provide additional recommendations. Retaining walls should be backfilled with free draining material that extends along the height of the wall, and a distance of at least 18 inches behind the wall. The upper one foot of the wall backfill can consist of a less permeable soil, if desired. A rigid, perforated drain pipe should be placed along the base of the wall, and connected to an appropriate discharge location. A typical retaining wall and drainage detail is illustrated on Plate 4 of this report. Drainage The presence of groundwater seepage should be expected in the building site excavations and the utility trench excavations. Temporary measures to control groundwater and surface water runoff during construction will likely involve the use of interceptor trenches, sumps and associated conveyance systems. Interceptor trenches should be installed along the cut slope areas as necessary during the mass grading of the site. The geotechnical engineer should observe site conditions during the grading and utility installation and provide supplement recommendations for drainage, as appropriate. In our opinion, perimeter footing drains should be installed at or below the invert of the building footings. A typical footing drain detail is provided on Plate 5 of this report. Water should not be allowed to flow over the adjacent slopes. Provisions should be included in site designs to either tightiine drainage elements to the base of the slope or convey runoff to an approved discharge point away from the slope area. LIMITATIONS The recommendations and conclusions provided in this geotechnical engineering study are professional opinions consistent with the level of care and skill that is typical of other members in the profession currently practicing under similar conditions in this area. A warranty is not expressed or implied. Variations in the soil and groundwater conditions observed at the test pit locations may exist, and may not become evident until construction. ESNW should reevaluate the conclusions in this geotechnical engineering study if variations are encountered. Earth Solutions NW, LLC Tom and Lin Hillman May 9, 2012 Revised July 16, 2012 Additional Services ES -2348 Page 9 ESNW should have an opportunity to review the final design with respect to the geotechnical recommendations provided in this study. ESNW should also be retained to provide testing and consultation services during construction. Earth Solutions NW, LLC Reference-, RORTA Snobcmish County, Washington Wip 454 By The'rhomas Giude Rand McNaHy Und �d�tjoni "AAA, ;W NKI IN LlWN 11", J14, i N l', A� c� m .. .. .. ... . "I V Po to E ty TAX vi L i, _VP tlppN OAA.1. YT* Reference-, RORTA Snobcmish County, Washington Wip 454 By The'rhomas Giude Rand McNaHy Und �d�tjoni EA Vicincl' y Map HiUman Single Family Residence Edmonds, Washington NOTE: Pis plWo may wMajo arm ol �olor. ESNN canno be Drwn. GUS Date 04/1H,112O12 Pripf, INo. 2348 rigs pcos)ible for any subsequem mishlerpFewfion of 11winformation resultmig fmn blaid, & wWe repmducWns of this plate. Checked SHA !Datan Aprd 2012 Plate,11 "AAA, 4e H wim NKI IN LlWN 11", J14, i N l', A� .10 .. .. .. ... . .w 10 Po EA Vicincl' y Map HiUman Single Family Residence Edmonds, Washington NOTE: Pis plWo may wMajo arm ol �olor. ESNN canno be Drwn. GUS Date 04/1H,112O12 Pripf, INo. 2348 rigs pcos)ible for any subsequem mishlerpFewfion of 11winformation resultmig fmn blaid, & wWe repmducWns of this plate. Checked SHA !Datan Aprd 2012 Plate,11 I E R, 111y.� A 2) ,9 222 Wedor Line 222 '124 HH -3 FIH,4 UnVI ge '26 % 3uI'I)IdiTjg H Envellope < 'R HH4' e'- u, �-rpj 214l 2'28 224 PPO I HH -l-,--- .—Approximate Location of ESNW Hand Hole, PrDj. No. ES -2348, April 20,12 I I Subject Site E:1 Proposed Building NOTE Tfto graphics sh(mnon H'i is plalearre not otendod fix rJugign purposes or predse, scalle meowrernprN' tA'11 QMY W Plu"Walf, the appiaArrate IeV l alioris Telative, w the appiakinate loco'kps of existing andil G.r proposed site features, The information ithiMialed is I-argety, based an data provided by thti tient at fliefirno of emir sturdy- E$W uinnol be resporm6fe, for siksequeM design chariges or Werpretaflon of the dala by, other's. NOTE This plate may corp in arpas, of color, r8NW rannot be responsible U any sub!sequent (14 the 'FifacnIF&On fesu hOg from f)larik, & vol'i iw reprod o aw is of Phiis pla le, 0 16 3 Of 60 D. -ale �n Feet SCHEMATIC ONLY - NOTTO SCALE. NOT A CON$TRUICTION DRAWINO final dopa Giradiient Compacted Slope Face Bench ands Keyway Hill to consist of s w. r1ablg ra n u lar niaterial approved by the 2 ir - - - - Gleotechncial Engineer Existing Grade ni Typical "Berich" Keyed into Existing Slope FaQu Gcrate chnicat Engineer -lo, Verify r .Key (Minimumi 2'Deep by 6'Wide) 1712 DOMM 5ope should be strapped of topsoil and unsuitable materials pirijor to excavafingi Key Way or bionche;s. Benches WH typically be equal to a dozer blade width, approximataly B feet, but a rn I in, I unurnof 4 feet, Final slope gra0ent shcmld be 2 - 1 (horizontal vertfcal). Final slope face should �e densified by over -building with compacted Ml and trimm0g back. to shape or by compaction with dozer or ropier. ci P Ian t 1 ng or In yd roseed 1 n g slope face with a rapid growth deep rooted Yegetative riat will reduce, erosion potential of slops, area.. We of pegged in pI,auejute ruatfing or geotechnicM fab,6c wifl Wip, waintai*i the seed and mulch in place until the root system has an opporttAnity to germinate, StrUCtUiral fill should ba placed do ffin loose Ms riot, exceedinig 12 inches in thickness, Each fift shoud be oompacted to no, less than the degree sperifiled in the "Site Preparation and Earth Work" secfion of this report. No additional lift should be placed until compaction is 80hieved, Free Diraining Backfill shou[d consist of,50 having 1 5 Ihan, 5 percent fines. Percent passing #4 should be 25 to 75 percent. Sheet Drain ma,,, be feasibW in fleo al Free Warning BaQkfifl per ESNVV recommendations, Dr Pipe should consist of perforated, 6gnd PVC Pipe surrounded with 1"' Drain Rock- UN Free Draining Structural Backfill 1, 01i . 1w, 1 irich Drain Rock, Structural' Fill ,, Perforated, IDra,in Pipe �Surround In DraJin Rock) SCHEMATIC ONLY - NOT TO SCALE NOT A CONISTRUICTItil DRAWiNG Edmonds, Washington ,fwn. GLS Date 051 2 Proj", NO, 2348 Checked SHA Dule May, 2012 Plate 4, Perforated Rigiid Drain Pipe (Sunound wlth 1" Bock) NOTES; Do 01" tae rest' downspout s to Foctingi Drain. o Surface SeW to consist of 12" of less peri-neable, suftab)e sod, SlOpe away from building., E-1 Surlace Seal; native sod ur other Ilow permeabifity, materia[ 1""' Drai n Rock, SCHEMATIC ONLY - NOT'ro SO ALE NO'TA CONSTRUCTION DRAWINGi APPENDIX A SUBSURFACE EXPLORATION ES -2348 Subsurface conditions at the site were previously explored by excavating a series of hand holes. The approximate locations of the hand holes are illustrated on the Hand Hole Location Plan. The logs are provided in this Appendix. The stratification lines on the logs represent the approximate boundaries between soil types. In actuality, the transitions may be more gradual. We reviewed the previously referenced Test Pit Logs prepared by (AESI) in the preparation of this study, Earth Solutions NW, LLC Earth li LLC SOIL CLASSIFICATION CHART MAJOR DIVISIONS SYMBOLS TYPICAL DESCRIPTIONS GRAPH I LETTER GRAVEL AND CLEAN• GRAVELS®® •■ • ® GW WELL -GRADED GRAVELS, GRAVEL - FSAND INES MIXTURES, LITTLE OR NO GRAVELLY SOILS (LITTLE OR NO FINES) pOpOo 0 GP POORLY -GRADED GRAVELS, GRAVEL - SAND MIXTURES, LITTLE p,o O OR NO COARSE GRAINED SOILS MORE THAN 50% OF COARSE FRACTION GRAVELS WITH FINES °Q °° ° 4 D o GM SILTY GRAVELS, GRAVEL -SAND - SILT MIXTURES RETAINED ON NO. b SIEVE (APPRECIABLE AMOUNT OF FINES) GC CLAYEY GRAVELS, GRAVEL - SAND - CLAY MIXTURES SAND AND C LEAN SANDS SW WELL -GRADED SANDS, GRAVELLY SANDS, LITTLE OR NO FINES MORE THAN 50% OF MATERIAL IS SP POORLY -GRADED SANDS, GRAVELLY SAND, LITTLE OR NO FINES LARGER THAN NO. 200 SIEVE SIZE SANDY SOILS (LITTLE OR NO FINES) SANDS WITHSM FINES ' ' "' SILTY SANDS, SAND - SILT MIXTURES MORE THAN 50% OF COARSE FRACTION oo PASSING ON NO. b SIEVE (APPRECIABLE AMOUNT OF FINES) SC CLAYEY SANDS, SAND - CLAY MIXTURES INORGANIC SILTS AND VERY FINE ML SANDS, ROCK FLOUR, SILTY OR CLAYEY FINE SANDS OR CLAYEY SILTS WITH SLIGHT PLASTICITY FINE GRAINED SOILS SOILS SILTS LIQUID LIMIT AND LESS THAN 50 CL INORGANIC CLAYS OF LOW TO MEDIUM PLASTICITY, GRAVELLY CLAYSCLAYS, LEAN CLAYS SANDY — — — — OL ORGANIC SILTS AND ORGANIC SILTY CLAYS OF LOW PLASTICITY MORE THAN 50% OF MATERIAL IS SMALLER THAN NO. 200 SIEVE MH INORGANIC SILTS, MICACEOUS OR DIATOMACEOUS FINE SAND OR SILTY SOILS slzE SILTS LIQUID LIMIT AND CLAYS GREATER THAN 5D CH INORGANIC CLAYS OF HIGH PLASTICITY OH ORGANIC CLAYS OF MEDIUM TO HIGH PLASTICITY, ORGANIC SILTS HIGHLY ORGANIC SOILS PT PEAT, HUMUS, SWAMP SOILS WITH HIGH ORGANIC CONTENTS DUAL SYMBOLS are used to indicate borderline soil classifications. The discussion in the text of this report is necessary for a proper understanding of the nature of the material presented in the attached logs. Earth SolutionS NW 1605 1361h PInca, Nf,. Suito 201 a0evue, Was hingtor108005 Talophonw 4254284-33C30 BiORING, NUMBER HH -1 PACE I or i CLIENT Hillrean PROJECT NAME ResOonre PROAECTNUMBER 2348 PROJECTLOCA'TION Edmonds, Woohinglon DATESTARTED, 4012 COMPLETED 412112, GROUND ELEVMITI A03 299 f1 HOLIC Sl DRILLING CONTRACTOR ESNIVV Rep GROUND WATER LEVELS; DRILLING: METHOD AT TIME, F DRILLING LOGGED BY' 8111 CHIECKED, BY SHA AT END UP DFOLLINO NOTES , Depth or, Topscnl & S1(Xj W", fews AFTER DRILLING M -water Seepage Irri drug,Clociol'"I'di liand IDIe term�nalcd ot 4,0 feetholow ex WIng gr,ade, Graundwater "epago encoun'terod, at 2.75foof during excavoltom Soffom of hoIe at 4.0 feel. .... . . ...... MATERIAL DESGRIPTION 2z 0 . ........ . . . . ............ .0 Tj . ... ... . o,5 arown Silty Abwb glavo, M1041",wm dense, wait (wemt*iod T11) M -water Seepage Irri drug,Clociol'"I'di liand IDIe term�nalcd ot 4,0 feetholow ex WIng gr,ade, Graundwater "epago encoun'terod, at 2.75foof during excavoltom Soffom of hoIe at 4.0 feel. Earth Solutions NW BORING NUMBER HH - 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Hillman — — PROJECT NAME Hitlrrgan Single Family Residence PROJECT NUMBER 2348PROJECT LOCATION Edmond�� Washinaton -- --- - - __ - -- - - -- - DATE STARTED 412112 COMPLETED 4/2/12 GROUND ELEVATION 224 It HOLE SIZE DRILLING CONTRACTOR ESNW ReD GROUND WATER LEVELS: DRILLING METHOD AT TIME OF DRILLING LOGGED BY SHACHECKED BY SHA AT END OF DRILLING NOTES Depth_ of Topsoil &Sod 6": blackberries __ -__-__ AFTER DRILLING Lu a W wTESTS v a 0 MATERIAL DESCRIPTION az o_ TPSL ` ` 0.5 TOPSOIL 223.5 _ -- w.,. --------- --Brown T - - -- - ---- Brownsilty SAND with gravel medium dense, wet (Weathered Till) MC = 21.90% SM -water seepage 3.0 -becomes dense 221 0 --- --- - -- -- __ --- — _- __ -- - — ---------------- -- Hand Hole terminated at 3.0 feet below existing grade. Groundwater seepage encountered at 1.5 feet during excavation. Bottom of hole at 3.0 feet. Earth Solutbris NW BORING NIUMBER HH -3 U15 136th PlIaCe N,E, $Vite 201 PAOE 11 OF 1 Rlr I seftvue, Washington 98005 Gr Twephonn. 42�4184-3300 CLIENT -1111 wri NROJECA' twIAMNNE f uUrnion uG, 1, 05 1;0ace PROJECTNUMBER P1R0J1E(:TIL 0CAfWN Edniiantar waFbioglion DATE STARTED 4Q112 COMPLETED 412112 GROUND ELEVATTON 221 R HOLIESIZE DRIMNOCONTRACTOR FSNVVIRop GIROUND WATER LEVELS! DRILLING PJLTHOD AT TIME W ORILUNQ LOGGED BY SHA GHECKED BY SHIA AT END OF DRILLING -7 NOTES Onyth, ofTqps08. Sad ff': fajns AFTERDRILUING UJI a., U MATERIAL DESCRIPTION D IL 10.�S, �2101,15 Brown sky SAND wilth gravel, medfum densc moist (Weathered T41) -becomas danse, U Hand Hole'taTininated at 1 10 feel I telow, I e, I mififing grade, No groundwaLer 11 e I n,c 1 0 1 1 1 inlere 11 d - dL I W I n . Q a I x I ca I va - I I on, Bottarn of hale at 3.0 feet, Earth Solutions NW BORING NUM HH -4 1805 136th Place N.E., Suite 201 PAGE 1 OF 1 2,12111111 Bellevue, Washington 98005 Telephone: 425-284-3300 CLIENT Hillman PROJECT NAME Hillman Single FamilyBesidence PROJECT NUMBER 2348PROJECT LOCATION Edmonds, Washington - - — — - - - --- --------- — DATE STARTED 4/2/12 _ COMPLETED _4/2/12 ----- _ GROUND ELEVATION 218 ft HOLE SIZE DATE DRILLING CONTRACTOR ESNW Rep GROUND WATER LEVELS: DRILLING METHOD AT TIME OF DRILLING -- LOGGED BY SHA CHECKED BY SHA AT END OF DRILLING NOTES _Depth of Topsoil & Sod 8": duff __ AFTER DRILLING w LU U _ wL LU g TESTS ( = EL J MATERIAL DESCRIPTION o a� Q z c9 0 TPSL `- `` 0.5 TOPSOIL 217.5 Gray silty SAND with gravel, medium dense, moist (Weathered Till) SM -becomes dense, Till MC = 11.80% 3.0_------------- ___ _ 215.0 �� _ Hand Hole terminated at 3.0 feet below existing grade. No groundwater encountered during excavation. Bottom of hole at 3.0 feet. ES -2348 Earth Solutions NW, LLC Earth Solutions NW GRAIN SIZE DISTRIBUTION 1805 - 136th Place N.E., Suite 201 Bellevue, WA 98005 Telephone: 425-284-3300 CLIENT Tom -& Lin Hillman _ -,,_ PROJECT NAME Hillman SFR PROJECT NUMBERES-2348 _ PROJECT LOCATION Edmonds U.S. SIEVE OPENING IN INCHES I U.S. SIEVE NUMBERS I HYDROMETER B 4 3 2 1 3/4 1/23/8 3 4 6 810 1416 20 30 40 50 60 100 140 200 T I II 100 95 - 90 85 80 75 — 70 - 65 . 1 - � 60 Lu > 55 w m w50 z LL F- z w 40 w a 35 30 25 20 15 �m 5 _ 0 100 10 1 0.1 0.01 0.001 GRAIN SIZE IN MILLIMETERS GRAVEL SAND SILT OR CLAY COBBLES coarse rine coarse medium fine y. Specimen Identification Classification LL PL PI Cc Cu N q TP.4 3,pft, Gray silty SAND with gravel, SM a Specimen p Identification D100 D60 D30 D10 %Gravel %Sand %Silt %Clay o TP -0 3.Oft. 37.5 — 5.205 0.315 41.5 43.5 15.0 --- _ — UJ W N .*. ES -2348 EMAIL ONLY Tom and Lin Hillman 169816 - 74th Place West Edmonds, Washington 98026 Earth Solutions NK LLC 0'1^ 4 1' i 'o n i 1A i k r I I o r I T, r" V I 4� i I'm ibo, a F 14,,, r ro I I A r w 4P 951015 11 13 t h Am iije S E Sufte 1()6 Evereu, Washingtori 98208 (425) 337-3174 Rox (425), X,37,1045 CRITICAL AREA STUDY AND WETLAND MITIGATION PLAN HILLMAN — 1139, SIERRA PLACE . ............ . . ... . ....... .......... CITY OF EDMONDS, WA Wetland Resources, Inc. Project #11033 Prepared By: Wetla nd Re' -o a rc es, Inc. 9505 l9th Ave. SE, Suite 106 Everett, WA 98208 ('425) 337-3174 Prepared for. - Torn & Lin H01main 1-5915 74th K W Edmonds, WA 98026 Mlw ITHININFA DM—' 'OMENT SEW= TABLE OF CONTENTS INTRODUCTION 1 PROJECT PROPOSAL 1 SITE DESCRIPTION 1 WETLAND AND STREAM CLASSIFICATIONS - COWARDIN SYSTEM 2 WETLAND AND STREAM CLASSIFICATIONS - CITY OF EDMONDS 2 WETLAND DETERMINATION REPORT 3 BOUNDARY DETERMINATION FINDINGS 4 FUNCTIONS AND VALUES ASSESSMENT 5 PROJECT DESCRIPTION 7 MITIGATION APPROACH 8 POST -MITIGATION WETLAND FUNCTIONS AND VALUES ASSESSMENT 10 PROPOSED PLANTING PLAN 11 PLANTING NOTES 12 PROJECT SPECIFIC GOALS 12 PROJECT MONITORING PROGRAM 13 MAINTENANCE 14 CONTINGENCY PLAN 14 PERFORMANCE BOND 14 USE OF THIS REPORT 15 REFERENCES 16 ATTACHMENTS TABLE 2: PROJECT COMPARISON (1139 SIERRA PLACE) TABLE 3: COMPARISON OF NEIGHBORHOOD BUILDING AREAS FIGURE 1: AERIAL PHOTO OF SITE WETLAND RATING FORM FOR WESTERN WASHINGTON WETLAND DETERMINATION DATA FORMS (SITES 1 & 2) CRITICAL AREA STUDY MAP AND MITIGATION PLAN (SHEET 1/1) INTRODUCTION Per the request of Tom and Lin Hillman (the applicants), Wetland Resources, Inc. (WRI) conducted a site visit on March 2, 2011 to verify the previously delineated wetland and stream boundaries on the approximate 1 -acre site located at 1139 Sierra Place in the city of Edmonds, Washington (within a portion of Section 24, Township 27N, Range 3E, W.M.). The original delineation was performed in July 2003 by WRI. During the March 2011 site visit, only minor changes to the western wetland boundary were found. Appropriate modifications were made both on-site and in the attached drawings. PROJECT PROPOSAL A new project application for this site is proposed by new owners to construct a relatively modest -sized single-family residence within the western part of the property. The proposed plan would result in significantly less impact to the site when compared to the original application. The proposed development area is closest to the existing access to the site. Because the western part of the site is covered by wetlands, streams, and associated buffers, the applicant cannot achieve a reasonable economic use of the property through strict application of the provisions under Title 23 of the Edmonds Municipal Code. The applicant therefore proposes a variance, pursuant to 23.40.210 to achieve reasonable economic use of the property. Through this proposal, unavoidable impacts to on-site wetlands and buffers will be necessary. Impacts will be mitigated on-site to the greatest extent possible. The proposed impacts associated with this application are significantly reduced when compared to a previous building application for this site that included a proposal to construct a single-family residence in the eastern part of the site and an access driveway up the steep slopes leading to the new house. The previous project proposal would have filled over 50 percent more than the amount of wetland that is being proposed under the current applicant. It also would have required significant alteration and reconstruction of the existing slopes. The current project proposal is an improvement over what could have been constructed on the site. SITE DESCRIPTION Access to this site is from the east via Sierra Place. The site is situated on a west -facing aspect with an average grade of about 20 percent. The entire site is forested. Dominant tree species include red alder (Alnus rubra), western red cedar (Thuja plicata), Douglas fir (Pseudotsuga menziesii), and big leaf maple (Acer macrophyllum). Dominant understory vegetation consists of salmonberry (Rubus spectabilis), Himalayan blackberry (Rubus armeniucus). A Category III wetland occupies approximately the western two-thirds of this site, and extends off-site to the north and south. The total estimated size of this wetland, including off-site portions amounts to a little more than one-half acre. This wetland functions hydrogeomorphically as a slope wetland and primarily receives hydrology from groundwater Critical Area Study and Wetland Mitigation Plan 1 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 seeps and drainage from upslope properties. The wetland contains a vegetative community of red alder and a few western red cedars in the canopy, with a mix of native and non-native shrubs and herbaceous species. The wetland receives a total score of 37 points on the DOE wetland rating form (attached), which equates to a Category 3 wetland. The on-site wetland supports a Type Np stream, which flows from the wetland in multiple small channels. Towards the western portion of the site, these channels coalesce into one channel. This stream was flowing strongly during the recent 2011 site visit. This stream continues off-site to the west, where it passes through a concrete -lined ditch and into a culvert under Olympic Avenue. No outlet to this culvert was located. As a result, it is assumed that from this point hydrology from this stream is conveyed via the city stormwater system. The stream is not shown on water typing maps or fish distribution maps as containing fish habitat. Because of the lack of documented evidence, the multiple barriers and steep gradient (>16%) on the site, it is presumed that the stream is a non -fish bearing stream, and shall be classified as a Type Np stream. In the city of Edmonds, Category 3 wetlands typically receive 50 -foot protective buffers per Section 23.50.040(F)(1)(c) and Type Np streams receive 50 -foot protective buffers per Section 23.90.040(D)(1). Due to existing soil types (Alderwood soils, 15 to 25 percent slopes), the on-site slopes appear to be designated as erosion hazard areas. A Geological Hazards Assessment shall be prepared by a quality professional, Pursuant to 23.80.050, as part of a building application for this site. WETLAND AND STREAM CLASSIFICATIONS — COWARDIN SYSTEM According to the Cowardin System, as described in Classification of Wetlands and Deepwater Habitats of the United States, the classifications for the on-site wetland and stream are as follows: Wetland: Palustrine, Forested, Broad-leaved Deciduous, Seasonally Flooded Stream 1: Riverine, Upper Perennial, Unconsolidated Bottom, Cobble-gravel/Mud WETLAND AND STREAM CLASSIFICATIONS — CITY OF EDMONDS Under City of Edmonds Code Chapter 23.50, the on-site wetlands, are classified according to the Washington State Department of Ecology (DOE) Wetland Rating System (SCC 30.62A.230(2); Hruby 2004). Streams shall be classified in accordance with the Washington Department of Natural Resources water typing system (WAC 222-16-030). The classifications of the on-site wetland and stream are as follows: Wetland - Category 3 The on-site wetland is a slope wetland that receives a total score of total score of 37 points for functions on the DOE Wetland Rating Form. Wetlands attaining a total score for functions of 31-50 on the DOE Wetland Rating Form are classified as Category 3. In the city Critical Area Study and Wetland Mitigation Plan 2 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 of Edmonds, Category 3 wetlands receive standard buffers of 50 feet per Section 23.50.040(F)(1)(c). Stream - Type Np The stream channel is approximately 2 feet wide at the confluence in the western part of the property, but is less than 2 -feet wide further upslope. The stream channel is located on a slope grade that exceeds 16 percent. Its contributing basin is estimated to be less than 20 acres. There is no documented evidence that indicates that this stream contains fish habitat. Based on these existing conditions, the on-site stream appears to meet the criteria of a Type Np stream (non -fish, perennial). In the city of Edmonds, Type Np streams are dedicated 50 -foot protective buffers Section 23.90.040(D)(1). WETLAND DETERMINATION METHODOLOGY AND CRITERIA Methodology The Washington State Wetlands Identification and Delineation Manual (Washington State Department of Ecology Publication #96-94, March 1997) was used for this determination, as required by Snohomish County. Under this method, the process for making a wetland determination is based on three sequential steps: 1) Examination of the site for hydrophytic vegetation (species present and percent cover); 2) If hydrophytic vegetation is found, then the presence of hydric soils is determined; 3) The final step is determining if wetland hydrology exists in the area examined under the first two steps. The following criteria descriptions were used in the boundary determination: Vegetation Criteria The Washington State Wetlands Identification and Delineation Manual, 1997 edition, defines hydrophytic vegetation as the "sum total of macrophytic plant life that occurs in areas where the frequency and duration of inundation or soil saturation produce permanently or periodically saturated soils of sufficient duration to exert a controlling influence on the plant species present." One of the most common indicators for hydrophytic vegetation is when more than 50 percent of a plant community consists of species rated "Facultative" and wetter on lists of plant species that occur in wetlands. Soils Criteria and Mapped Description The Washington State Wetlands Identification and Delineation Manual, 1997 edition, defines hydric soils as those "that formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper part." Field indicators are used for determining whether a given soil meets the definition for hydric soils. The soils underlying the subject property are mapped in the Soil Survey of Snohomish County Area Washington as Alderwood gravelly sandy loam, 15 to 25 percent slopes Critical Area Study and Wetland Mitigation Plan 3 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 Alderwood gravelly sandy loam is described as a moderately well drained soil on till plains. It is moderately deep over a hardpan. This soil formed in glacial till. Typically, the surface layer is very dark grayish brown gravelly sandy loam about 7 inches thick. The upper part of the subsoil is dark yellowish brown and dark brown very gravelly sandy loam about 23 inches thick. Included in this unit are small areas of soils that are similar to this Alderwood soil but have cobbles or stones on the surface, Also included are small areas of Everett, Indianola, and Ragnar soils on terraces and eskers. Included areas make up about 15 percent of the total acreage. Permeability of this soil is moderately rapid above the hardpan and very slow through it. Available water capacity is low. Soils sampled on site appear similar to the description for this series. Hydrology Criteria The Washington State Wetlands Identification and Delineation Manual, 1997 edition, states that "areas which are seasonally inundated and/or saturated to the surface for a consecutive number of days >_12.5 percent of the growing season are wetlands, provided the soil and vegetation parameters are met. Areas inundated or saturated between 5 and 12.5 percent of the growing season in most years may or may not be wetlands. Areas saturated to the surface for less than 5 percent of the growing season are non -wetlands." Field indicators are used for determining whether wetland hydrology parameters are met. BOUNDARY DETERMINATION FINDINGS Wetland Dominant species within the areas mapped as wetlands include: red alder (Alnus rubra, Fac), salmonberry (Rubus spectabilis, Fac+), and Himalayan blackberry (Rubus armeniucus, FacU). The soils are typically black (10YR 2/1) mucky gravelly sandy loam in the upper 12 inches and very dark gray (10YR 3/1) gravelly sandy loam in the sublayer. The soils were saturated within the upper 18 inches of the surface at the time of the March 2011 site visit. The dominance of species rated "Facultative" or wetter meets the criteria for hydrophytic vegetation in this wetland. Based on field indicators, it appears that the area mapped as wetland is saturated to the surface for more than 12.5 percent of the growing season, thereby fulfilling wetland hydrology criteria. Non -wetland Areas Dominant vegetation within the areas mapped as non -wetland includes: Western red cedar (Thuja plicata, Fac), Douglas fir (Pseudotsuga menzeisii, FacU), big -leaf maple (Acer macrophylum, FacU), red alder (Alnus rubra, Fac), Himalayan blackberry (Rubus armeniucus, FacU), salmonberry (Rubus spectabilis, Fac+), sword fern (Polystichum munitim, FacU), English ivy (Hedera helix, FacU), English laurel (Prunus laurocerasus, UPL), and English holly (Ilex aquifolium, FacU). Soils in the non -wetland portions of the site are typically very dark grayish brown (10YR 3/2) gravelly sandy loam to a depth of 4 inches below the surface and dark brown (10YR 3/3) gravelly sandy loam from 4 to 18 inches below the surface. These soils were slightly moist Critical Area Study and Wetland Mitigation Plan 4 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 at the time of the March 2011 site investigation. The soil type described above does not indicate persistent wetland hydrology. Based on the lack of field indicators, it appears that areas of the site mapped as non - wetland are not saturated to the surface for more than 12.5 percent of the growing season, thereby not fulfilling wetland hydrology criteria. FUNCTIONS AND VALUES ASSESSMENT Methodology The methodology for this functions and values assessment is based on professional opinion developed through past field analyses and interpretations. This assessment pertains specifically to the on-site wetland system, but is typical for assessments of similar systems common to western Washington. Functions and Values Components Wetlands in western Washington perform a variety of ecosystem functions. Included among the most important functions provided by wetlands are stormwater control, water quality improvement, fish and wildlife habitat, aesthetic value, recreational opportunities, and education. The most commonly assessed functions are Stormwater Storage/Floodflow Attenuation, Water Quality, and Wildlife Habitat. Assessments of these functions for the project site are provided below. Pre -disturbance Assessment The on-site wetland is hydrogeomorphically (HGM) classified as a slope wetland because it is located on a hillside and contains ground water seeps that "daylight" and flow through the wetland without being impounded. Slope wetlands do not improve water quality or control floodwaters to the same extent as depressional or riverine wetlands because they lack the physical characteristics to be able to impound surface water for treatment and/or flood control. Water Quality With its location on a relatively steep slope, the subject wetland has limited ability to trap excess surface waters that flow through it. The existence of organic soil in the upper 12 inches of the soil profile as well as the existence of moderate herbaceous plant cover does provide some water quality benefit for down stream systems. However, this wetland generally rates low for this function because of its other characteristics. Minor improvements could be made through enhancement by planting additional herbaceous species within the bare ground areas of the wetland. Hydrologic control While this wetland functions to maintain base flows for the on-site stream, it holds a low capacity for reducing peak flows. Similar to water quality functions, the on-site wetland has a severely limited potential to provide flood control functions because of its lack of depressional features and lack of ability to become ponded. The wetland contains moderate coverage of rigid vegetation that may help slow velocity. Critical Area Study and Wetland Mitigation Plan 5 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 Minor improvements to this function could be made through enhancement by planting additional woody species in open areas of the wetland. Wildlife habitat function The wetland and adjacent upland areas are completely isolated by suburban development and cover only about an acre of undisturbed forestland. As such, connection to other diverse habitats is limited. Species habitat features are limited within the wetland and its buffer. The wetland therefore receives a low score for habitat functions. Minor improvements to these functions could be made through enhancement of species richness in the wetland. This would be achieved through planting of a diversity of native trees and shrubs within the wetland area. Type Np Stream The on-site perennial stream serves to collect and convey water from the associated wetland and transport it to downstream systems. This stream also provides potential habitat and forage opportunities for birds, small mammals, reptiles, and amphibians. The stream only flows for a relatively short distance before it enters the city stormwater system. It should be noted that the on site stream drains many of the properties on 12th Avenue North; and the section of stream that crosses the subject property is confined to a storm drain before it enters the property and is confined to a storm drain after it leaves the property. Conclusion Based on existing conditions, it appears that the wetland and stream system provides moderately low levels of the analyzed functions. Some factors limiting peak performance include the presence of invasive species in the wetland and buffer (mainly Himalayan blackberry). Potential Impacts to Functions and Values To achieve a reasonable use of the property, a portion of the on-site wetland and stream/wetland buffer areas will be permanently impacted for construction of a modest single-family residence. The total area of permanent wetland impact will amount to 1,790 square feet while the total area of buffer impact will amount to 3,920 square feet. Placing a single-family residence adjacent to the wetland results in complete elimination of its protective buffer along a portion of it. The areas to be impacted are within a relatively level area at the bottom of the slope on the subject site. Vegetation to be removed primarily consists of volunteer red alder covered in English ivy, as well as salmonberry, Himalayan blackberry and sword fern. Impacts associated with the proposed home construction will affect the infiltrative capacity of that that portion of the site. However, the overall impact is relatively low when compared to the low level of function offered by the wetland upslope of the proposed development. Limited long-term water quality impacts may result from the removal of vegetation and placement of new impervious surface. These impacts shall be mitigated by directing runoff from impervious surfaces into a tight -lined system that precludes sediment contribution Critical Area Study and Wetland Mitigation Plan 6 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 prior to discharge. Alternative strategies, such as bioswale infiltration techniques, were considered for this site. However, it was determined that infiltration cannot be achieved on this site due to the shallow layer of glacial till over an impermeable layer (see geotechnical report by Earth Solutions NW). Short-term water quality impacts will be mitigated during construction through installation of BMP erosion control fencing at the down slope clearing limits. Through removal of vegetation on the site, some wildlife species inhabiting the area may be displaced. Impacted wildlife would be limited to small birds, small mammals and insects. The area to be impacted does not support habitat for rare or endangered species, therefore no loss of significant species is expected. Based on existing and anticipated conditions, the proposed development is expected to reduce the level of existing functions on the site somewhat. However, the overall cumulative affects, when compared to the developed areas surrounding the site, are expected to be relatively minimal. PROJECT DESCRIPTION The applicant is proposing to construct a relatively modest single-family residence with associated driveway and small yard and porches within the southwestern corner of the property. This will be achieved through the variance process under Chapter 23.40.210. Below is an explanation of how this application meets the criteria that warrant a variance. Variances from the standards in Chapter 23.40 may be authorized through the process of hearing examiner provided that the applicant demonstrates the following: 1) The application of this title would deny all reasonable economic use of a property or subject parcel; The on-site wetland, stream, and associated buffers occupy about 78% of the subject property. Because of this, strict application of the standards set forth in Title 23 would prohibit a reasonable development on the site. 2) No other reasonable economic use of the property consistent with the underlying zoning and the city comprehensive plan has less impact on the critical area; There is no other reasonable use for the site than residential that would result in less impact. 3) The proposed impact to the critical area is the minimum necessary to allow for reasonable economic use of the property; The applicant has carefully considered the house design and size. The total footprint and living space is considerably more modest that those of the surrounding properties (see Table Critical Area Study and Wetland Mitigation Plan 7 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 2). The research and design work clearly demonstrate that the proposed development is the minimum necessary to achieve a reasonable economic use of the property. 4) The inability of the applicant to derive reasonable economic use of the property is not the result of actions by the applicant after the effective date of the ordinance codified in this title or its predecessor; No actions by the applicant have been carried out that have resulted in the inability to derive reasonable economic use of the site. There are no outstanding violations, boundary line adjustments, or anything of the like associated with this site. 5) The proposal does not pose an unreasonable threat to the public health, safety, or welfare on or off the development proposal site; The proposed development will not be hazardous to public health, safety, or welfare. The project has been carefully designed to minimize site impacts to the greatest extent possible. It will not affect water quality or create flooding issues in downstream systems. The location of the development on the site is not expected to create erosion hazards or additional tree hazards for neighboring properties. 6) The proposal minimizes net loss of critical area functions and values consistent with the best available science; and The proposal has been carefully designed to minimize net loss of on-site functions. A watershed approach to protection and mitigation design has been considered as part of the proposed mitigation measures. 7) The proposal is consistent with other applicable regulations and standards. All other regulations and design standards are being applied as part of this application. MITIGATION APPROACH Mitigation Sequencing The hierarchy of review criteria is as follows: avoid impacts, minimize impacts, repair or restore impacts, and compensate for impacts. Below is a discussion of steps taken to avoid, minimize, and compensate for impacts related to the existing impact: 1. Avoiding the impact altogether by not taking a certain action or parts of an action; Because the portion of the property adjacent to the access point consists almost entirely of wetland and buffer areas, complete avoidance of the on-site wetland and buffers cannot be achieved in conjunction with achieving minimum economic use of the site. Critical Area Study and Wetland Mitigation Plan 8 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 2. Minimizing impacts by limiting the degree or magnitude of the action and its implementation by using appropriate technology or by taking affirmative steps, such as project redesign, relocation, or timing, to avoid or reduce impacts; Consideration is given to the fact that there is a non -wetland or buffer area in the eastern part of the property. However, obtaining access to that would require a substantial amount of construction and modification to the existing slopes and wetlands on the site. As such, constructing a house in the eastern part of the site would result in significantly more wetland, buffer, and slope impacts than what is currently being proposed. The proposed house design, size, and its location on the landscape results in the least amount of impact that could occur on the site. To further minimize impacts, the applicant is proposing to reduce the standard building line setback (per Section 23.40.280) from 15 feet to 5 feet along wetland edge and 3 feet along the stream buffer edge. This leaves a larger amount of critical areas and buffer intact, and clearly demonstrates that minimization of impacts has been achieved to the greatest extent possible. 3. Rectifying the impact to wetlands, frequently flooded areas, and fish and wildlife habitat conservation areas by repairing, rehabilitating, or restoring the affected environment to the historical conditions or the conditions existing at the time of the initiation of the project; This cannot be achieved because all impacts are permanent. 4. Minimizing or eliminating the hazard by restoring or stabilizing the hazard area through engineering or other methods Hazard slopes and stormwater runoff will be evaluated and a mitigation design will be prepared by a professional engineer. 5. Reducing or eliminating the impact or hazard over time by preservation and maintenance operations during the life of the action; All areas proposed to remain intact or be enhanced (approximately 3/4 of the site) will be enhanced, maintained and permanently protected by the landowners. 6. Compensating for the impact to wetlands, frequently flooded areas, and fish and wildlife habitat conservation areas by replacing, enhancing, or providing substitute resources or environments; and/or For impacting 1,790 square feet of wetland, the applicant shall enhance a total of 15,560 square feet of remaining wetland on the site for an 8:1 ratio. For 3,920 square feet of Critical Area Study and Wetland Mitigation Plan 9 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 permanent buffer impacts, the applicant shall enhance a total of 2,410 square feet of buffer in the northwestern part of the site for a .5:1 replacement to impact ratio. 1 7. Monitoring the hazard or other required mitigation and taking remedial action when necessary. A three-year monitoring program will be implemented following successful installation of the mitigation plan. Proposed Mitigation Measures To mitigate for permanent impacts to a total of 1,790 square feet of wetland, the applicant proposes to enhance a total of 15,560 square feet of wetland at a 8:1 ratio, which exceeds the 4:1 requirements under EMC Section 23.50.050(G). To mitigate for a total of 3,920 square feet of buffer impact, the applicant proposes to enhance total of 2,410 square feet of buffer in the northwestern corner of the property at a .5:1 ratio. After careful consideration and analysis, it was determined that wetland creation as mitigation could not be reasonably achieved on the site. The only available non -wetland areas on the site are upslope in the eastern part of the site. To construct wetlands on that part of the property would be difficult because of the uncertainty of whether sufficient natural hydrology could be created. Furthermore, creation of on-site wetlands within the eastern part of the property would require heavy excavation equipment to cross the existing wetlands, creating additional impacts to the wetland areas. Creation of wetland would also require clearing and grading within forested buffer areas. It is generally impractical to disturb forested habitat for the sake of wetland mitigation if alternative mitigation measures can be achieved. Based on these conditions, it was determined that wetland creation could not be achieved on the site. Similarly, buffer creation as a mitigation option was eliminated based on the steep slopes and difficult access at the eastern portion of the property. Providing double the required ratio for wetland enhancement is the preferred option for mitigating the buffer impacts in this case. Off-site mitigation has also been considered and determined to be unachievable. The applicant would have limited access to other privately owned lands within the same drainage basin. Furthermore, because of the vast coverage of suburban development in the area, few areas within the same drainage basin are available for potential improvement. 1 The City's code does not specify a minimum ratio for buffer replacement nor enhancement. Additionally, the existing 50 -foot wide eastern buffer shall remain undisturbed. Critical Area Study and Wetland Mitigation Plan 10 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 In the interest of implementing a watershed approach to the greatest extent possible, it appears that on-site wetland enhancement is the most reasonable mitigation approach. Because of the presence of invasive weeds and relatively low native plant diversity in the wetland areas, it appears to be more practical to enhance the existing wetland and improve its overall value than creating new wetland or mitigating off-site. Mitigation Ratios The applicant will propose the following combination of mitigation measures: Table 1: Proposed Wetland and Buffer Mitigation Ratios POST -MITIGATION WETLAND FUNCTIONS AND VALUES ASSESSMENT The intent of the proposed mitigation measures is to have a no net loss of functions and values after development of the site. This will be achieved through wetland and buffer enhancement as well as leaving the entire existing eastern 50 -foot wetland buffer area undisturbed. A relatively small area of wetland Oust over 10 percent) will be filled through this proposal. The portion to be filled is saturated only in the wettest time of the year, thereby currently offering limited stormwater control functions. Therefore, through properly implemented mitigation measures, no significant loss of stormwater control functions is expected. Any loss of this function can be acheived through the proposed stormwater detention design and wetland enhancement. All collected stormwater will drain to a detention feature that drains to the on-site stream. Woody species planted within the wetland areas upslope of the new house will slow the hydrologic flow through the wetland and buffer, thereby creating some resistance and hence improvement to hydrologic control functions on the site. The proposed wetland and buffer enhancement would also improve water quality functions. By planting bare ground areas with native sedges, suspended solids and other pollutants and nutrients will be trapped and absorbed as water flows through the enhanced wetland area. Wildlife habitat functions on-site would be greatly improved by the proposed mitigation measures. Habitat diversity is important for different wildlife species to thrive in an area. The proposed native trees and shrubs will provide increased habitat for birds and mammals to thrive. Thicker vegetation will provide hiding cover, thermal cover, and greater foraging opportunities for many birds and mammals. Many wildlife species would benefit from the proposed increase of vegetative structural diversity. Furthermore, the net increase of forested buffer habitat within the eastern part of the property ensures permanent protection of additional forested habitat areas on the site. Critical Area Study and Wetland Mitigation Plan 11 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 Mitigation Impacted I Ratio Mitigation Item Area Enhancement Required Ratio Wetland 1,790 SF 12,560 SF 4:1 8:1 Buffer 3,920 SF 2,410 N.A. .5:1 POST -MITIGATION WETLAND FUNCTIONS AND VALUES ASSESSMENT The intent of the proposed mitigation measures is to have a no net loss of functions and values after development of the site. This will be achieved through wetland and buffer enhancement as well as leaving the entire existing eastern 50 -foot wetland buffer area undisturbed. A relatively small area of wetland Oust over 10 percent) will be filled through this proposal. The portion to be filled is saturated only in the wettest time of the year, thereby currently offering limited stormwater control functions. Therefore, through properly implemented mitigation measures, no significant loss of stormwater control functions is expected. Any loss of this function can be acheived through the proposed stormwater detention design and wetland enhancement. All collected stormwater will drain to a detention feature that drains to the on-site stream. Woody species planted within the wetland areas upslope of the new house will slow the hydrologic flow through the wetland and buffer, thereby creating some resistance and hence improvement to hydrologic control functions on the site. The proposed wetland and buffer enhancement would also improve water quality functions. By planting bare ground areas with native sedges, suspended solids and other pollutants and nutrients will be trapped and absorbed as water flows through the enhanced wetland area. Wildlife habitat functions on-site would be greatly improved by the proposed mitigation measures. Habitat diversity is important for different wildlife species to thrive in an area. The proposed native trees and shrubs will provide increased habitat for birds and mammals to thrive. Thicker vegetation will provide hiding cover, thermal cover, and greater foraging opportunities for many birds and mammals. Many wildlife species would benefit from the proposed increase of vegetative structural diversity. Furthermore, the net increase of forested buffer habitat within the eastern part of the property ensures permanent protection of additional forested habitat areas on the site. Critical Area Study and Wetland Mitigation Plan 11 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 The plantings within the wetland enhancement areas are also intended to provide added protection to the wetland to mitigate the loss of vegetated buffer areas adjacent to the wetland. Based on anticipated conditions, proper implementation of the proposed mitigation measures will result in a net increase of wetland and buffer functions over time through vegetative enhancement. PROPOSED PLANTING PLAN Plans for enhancement of 15,560 square feet of wetland and 2,410 square feet of buffer will include removal of invasive, non-native plant species. Following invasive plant removal and other site preparations, the applicant proposes to plant native trees and shrubs in the designated areas. Plant spacing will be variable throughout the designated areas due to existing vegetation cover. Generally, plant spacing will be based on 60 percent of the area planted to trees on 15 -foot centers, 50 percent of the area planted to shrubs on 6 -foot centers. The sedge plantings proposed will be placed within bare ground areas or areas dominated by invasive herbaceous species. About 10 percent of the area will be planted with sedges. The combination of new plantings and existing vegetation should be adequate to achieve the plan densities of 8 -foot spacing for trees and 3 -foot spacing for shrubs prescribed in code Sections 23.90.040(D)(2)(b) for stream buffers and Section 23.50.040(F)(3)(b) for wetlands. The proposed distribution of native plants for wetland enhancement follows: Proposed Wetland Enhancement PlantinL5s (15.56n snuare fPPt) Common Name Latin Name Size Spacing uantit Western red cedar Thuja plicata 1 gallon 15' 8 Sitka spruce Picea sitchensis 1 gallon 15' 8 Oregon ash Fraxinous latifolia 1 gallon 15' 12 Pacific willow Salix lucida 1 gallon 6' 60 Sitka willow Salix sitchensis 1 gallon 6' 60 Red osier dogwood Cornus sericea 1 gallon 6' 60 Black twinberry Lonicera involucrata 1 gallon 6' 30 Slough sedge I Carex obnupta plug 2' 200 Sawbeak sedge I Carex stipata plug 2' 200 The following list of plants will be installed within the buffer enhancement areas following invasive plant removal. There is a sufficient quantity of plants listed to cover temporarily disturbed areas associated with installing the detention pipe and outfall. The proposed distribution of native plants for buffer enhancement follows: Critical Area Study and Wetland Mitigation Plan 12 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 Proposed Buffer Enhancement Plantings (2.410 square feet) Common Name Latin Name Size $acin uantit Western red cedar Thuja plicata 1 gallon 15' 4 Douglas fir Pseudotsuga menzeisii 1 gallon 15' 4 Oso -berry Oemleria cerasiformis 1 gallon 6' 15 Vine maple Acer circinatum 1 gallon 6' 15 Tall Oregon grape Mahonia aquifolium 1 gallon 6' 15 Red osier dogwood Cornus sericea 1 gallon 6' 10 Nootka rose Rosa nutkana 1 gallon 6' 10 Sword fern Polystichum 1 gallon 6' 20 PLANTING NOTES As part of the proposed enhancement plan, an access path will be necessary through the buffer and wetland areas to be planted. Its exact location will be determined during the preparation stages of the enhancement. Creating a path will include, but will not be limited to, some limited vegetation pruning. The path will be constructed out of pervious, natural materials, such as cedar or hemlock planks, wood chips, cut alder sections obtained from the building site, or any other suitable material. The applicant may begin invasive vegetation removal in the later winter/early spring 2012. A meeting will take place between the consulting biologist and the contracted landscaper prior to commencement of enhancement activities. This will provide an opportunity to clarify any questions that may arise and ensure success of the enhancement project in a timely manner. Silt fencing shall be placed as shown on the TESC design and be inspected prior to any mitigation site disturbance. Planting shall take place in the early spring or late fall. Potted plants should be obtained from a reputable nursery. All plant materials recommended in this plan are typically available from local and regional sources, depending on seasonal demand. Some limited species substitution may be allowed, only with the agreement of the consulting biologist or city representative. Care and handling of plant materials is extremely important to the overall success of the project. Lath stakes, or similar approved marking system, should be placed next to each tree and shrub to assist in locating the plants while removing the competing non-native vegetation. This will be done for all installed plants. Plants will be arranged in a pattern with the appropriate numbers, sizes, species, and distribution to achieve the desired vegetation coverage. The actual placement of individual plants shall mimic natural, asymmetric vegetation patterns found on similar undisturbed sites in the area. Critical Area Study and Wetland Mitigation Plan 13 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 PROJECT SPECIFIC GOALS The goal of this mitigation plan is to replace and improve the functions and values of the on- site critical areas and buffers to the greatest extent possible. To achieve this goal, three specific goals have been established and are listed below. Goal 1. Replace and improve impacted hydrologic functions within the wetland and buffer areas through the introduction of new plantings. • Implement stormwater control plans for the building site. • Plant native species within 15,560 square feet of wetland. • Plant native species within 2,410 square feet of buffer. Goal 2. Replace impacted functions associated with water quality improvement. • Implement a piped detention system to capture and control stormwater that drains off the new impervious surfaces, to minimize erosion and sediment into the stream. • Enhance the wetland with herbaceous plants to aid in water filtration. Goal 3. Increase Plant Species Richness within the wetland and stream buffer area. Remove invasive species and provide regular maintenance to ensure the success of the planted native species. Plant native trees and shrubs to discourage regeneration and recruitment of invasive species. PROJECT MONITORING PROGRAM Requirements for monitoring project: 1. Initial compliance report 2. Semi-annual site inspections (twice yearly, in the spring and fall) during years 1, 2 and 3. 3. Monitoring reports to be submitted to the city in the fall of years 1, 2 and 3. Purpose of Monitoring The purpose of monitoring this project is to evaluate the success of the enhancement plantings. Success will be determined if monitoring shows that at the end of three years that the performance standards are being met and that habitat values in the enhancement areas are equivalent to similar ecosystems in the immediate area. Inspection Schedule Upon completion of the mitigation project, an inspection by a qualified wetland biologist will be made to determine plan compliance. A compliance report will be supplied to the City of Edmonds regarding the completeness of the project. The project will be monitored for three years. Condition monitoring of the plantings will be done by a qualified wetland biologist in the spring and fall during years 1, 2 and 3. A written report describing the monitoring results Critical Area Study and Wetland Mitigation Plan 14 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 will be submitted to the City of Edmonds shortly after the fall inspection of each monitored year. Final inspection will occur at the third year following completion of planting. The contracted wetland professional will prepare a final report as to the success of the project. Vegetation monitoring transects and photo points will be established in the compliance report. Performance Standards Performance standards have been established to assess the success of the mitigation project in achieving the stated goals. Performance standards are as follows: Plant Survival Year 1 Monitoring Success Standard: 100 percent survival of planted species No greater than 20 percent coverage of invasive species Year 2 Monitoring Success Standard: Minimum 40 percent aerial coverage of native species No greater than 20 percent coverage of invasive species Year 3 Monitoring Success Standard: Minimum 70 percent aerial coverage of native species No greater than 20 percent coverage of invasive species MAINTENANCE The enhancement areas will require periodic maintenance during the monitoring period. The wetland enhancement will be maintained at least two times during the spring and once in the fall for each of the three monitored years, or as needed to assure the success of the mitigation project. Maintenance may include, but will not be limited to, removal of invasive vegetation, replacement of plant mortality, and/or the replacement of mulch for each maintenance period. CONTINGENCY PLAN If more than 20% of the plants are severely stressed during any of the inspections, or it appears more than 20% may not survive, additional plantings of the same species or, if necessary, alternative species may be added to the enhancement areas. If this situation persists into the next inspection, a meeting with a representative for the city of Edmonds, the consulting wetland biologist and the property owner will be scheduled to decide upon contingency plans. Elements of the contingency plan may include, but will not be limited to more aggressive weed control, plant mortality replacement, species substitution, fertilization, and/or soil amendments. Critical Area Study and Wetland Mitigation Plan 15 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 A perforroame bond shall be pirovidedl to Lhe city of Edmands for the period of three years from thie complebon of the project, in thQ aniount. of 1.20% of the estipinated cost for plant rnaterial and, [abor, The city of Edmonds sbaH release this bond at the end of the three years, upon successful determination for all portions of this rviligabon, project. The fol"llowing is an estimate of plant niaterials and labor only. This does not represent a bid to Estimated Project Cost QtI, ,jlnl tit,y of One -gallon plants Quantity of Plugs fim TOTAL ES'TIMATED SUND AMOUNT (120%) 3,31 @ $9.50/plaint 4,00, @ $3.00/Mant $3,144.510 $, 1, 0.0 RMRF� This Critical Area Study and Wetland Mitigation Plari is supplied to Torn & Lin Hillman as a means of providing rnifigation for wetland and buffer impacts, as required by, the city of, Ecirnands, during, the peirmitting proicess. This report is based largely on readily observable conditions and to a lesser extent,, on readily ascertainaWe conditions. No atternpt has benen made to doter gine Bidden or concealed conditions. Reports maybe adverselyaffected du,e to the physlca] condifloin, of the site and the difficulty of access, which (nay lead to observation or probirg difflouttles. The law's appficaWe to wetlands are subject to, varying interpretations and may be changed at any tirne by the, courts or le&latrlVe bodles, This report is intended to provIide information deemed relevant In the applicant's attempt to comply with the laws now in, effect. The work for ths report has conformed to the standard of care employed by wit-dand ecologmsts,,, No other representabon or warrainty is rnade concerning the work or this report and any irnpl ied representation or warranty is disclaimed. WeVan'd Resources' inc% " Dc" . .... ... . ,area Bachman Senior Wetland EcWogist CrMcal Area Study and Weiland Kfigationi Plain 'WIRI 411033 Hillman 113-0 S,Jerm Place, rLJIIY 1.8, 2012. REFERENCES City of Edmonds Municipal Code, Title 23. Edmonds, WA June 2007. Classification of Wetlands and Deepwater Habitats of the United States. FWS/OBS-79/31. December 1979. U.S. Department of the Interior, Fish and Wildlife Service. Washington, D.C. Geotechnical Engineering Study, Proposed Single Family Residence 1139 Sierra Place Edmonds, Washington (ES -2348). May 9, 2012. Earth Solutions NW, LLC, Bellevue, WA Hruby, T., K. Harper, and S. Stanley (2009). Selecting Wetland Mitigation Sites Using a Watershed Approach. Washington State Department of Ecology Publication #09-06-032. National List of Plant Species that Occur in Wetlands, Northwest Region. 1996. U.S. Department of the Interior, Fish and Wildlife Service. Washington, D.C. Soil Survey of Snohomish County Area Washington. United States Department of Agriculture, Soil Conservation Service (1978). Washington State Wetlands Identification and Delineation Manual. Washington State Department of Ecology. Publication #96-94. March 1997. Critical Area Study and Wetland Mitigation Plan 17 WRI #11033 Hillman - 1139 Sierra Place July 18, 2012 Table 2: PROJECT COMPARISON (1139 SIERRA PLACE) ITEM LEWIS PROJECT (Current Permit); HILLMAN PROJECT (Proposed) ADJACENT PROPERTIES AVERAGE Ground Floor Area 2,364 sf 1,772 sf 2,288 sf Gara a 1,003 sf 421 sf im erm 586 sf 714 sf Ground Floor Covered Porches/Deck ? 153 sf Unknown Building Footprint 4,146 sf 2,511 sf 3,002 sf Lot Coverage lot area = 40,511 sf 10.2% 5.8% 13.0% Roof overhangs 247 sf Driveway/Access Road 4,508 sf 740" sf Unknown Walkways 384 sf 0 Unknown Total New Impermeable Surface 8,654 sf 3,498 sf Storm Detention Tank Size Needed 30" dia X 59' 18" dia X 3C Ion `iLt! Second Floor Area 2,932 sf 851 sf 1,435 sf Total Interior Living Space 5,296 sf 2,623 sf 3,798 sf Second Floor Deck 156 sf Wetland Disturbance Area 2,867 sf(per WRI '09 report 1,790 sf Wetland Replacement Area 0 sf 0 sf Buffer Disturbance Area 10,436 sf 3,920 sf Wetland Enhancement Area 14,933 sf >5:1 15,560 sf >8:1 Buffer Enhancement 5,368 sf 0.5:1 2,410 sf 0.5:1 Gradinq Extensive Minimal to Moderate Length of Retaining Walls/Rockeries 245' 107' (+60' of garden walls <4' hi h Maximum height UX 2 rows = 12' 8' "Excludes portion in right-of-way. Advantages of the Hillman Plan over the Lewis Plan: 1. Proposed areas of clearing and tree removal are significantly smaller. 2. Proposed wetland disturbance area is reduced by over 25%. and proposed wetland enhancement area is larger. 3. Proposed buffer disturbance area is reduced by over 60%. 4. Proposed impermeable surface is reduced by 60%. 5. Proposed living space is less than half, and garage is smaller (and both are less than adjacent property averages). 6. Proposed grading and retaining structures are reduced by roughly half. 7. Proposed driveway is almost flat, compared to areas with over 18% slope. 8. Proposed house is near the existing fire hydrant. 9. More than 3/4 of the site is to be either enhanced or left undisturbed \\{��^ . y�»� ,© » .�. � . �� _ _ �/� ��.—,.: \\� } �\ .i ,2,\� . \\� �\� .# . . . . . . . : � � I .� .y. � \ «� �\� } � 2 .. �\ � � � y\. \y.. ./«y2: \/?© � < » � . ¥� :.<. �y . �\� <*� ;. < � . p . �. \ } y\ ©:§� . . » _�, . . �»*, . : \ \^. »� 5! � � � ^I � � � � »(» � 2 �� :?:: �:< � .\� \ «.»:.� y�y. .� � � f:..,� \w: � ,� � � . � £ \: � �» / � \\: . \ . \ � \° ¥ » a. . . y. y � � 2 � . :/� �» � \ � . , � ;� ' \\� � �% \ , . � � / \ � / .� / �\� * 2�� t 2 ^�� \ /\\ \ \ \ � \\�� \� � Wetland name or number Wetland A WETLAND RATING FORM — WESTERN WASHINGTON Version 2 - Updated July 2006 to increase accuracy and reproducibility among users Updated Oct 2008 with the new WDFW definitions for priority habitats Name of wetland (if known): Sierra Place Wetland Date of site visit: 3/2/11 Rated by A. Bachman Trained by Ecology? Yes ✓ONofj Date of training 11 /2006 SEC: 24 TWNSHP: 27N RNGE: 3E Is S/T/R in Appendix D? Yes_a No_a Map of wetland unit: Figure 1 Estimated size -0.5 Acres SUMMARY OF RATING Category based on FUNCTIONS provided by wetland I II III ✓ IV, Score for Water Quality Functions Category I = Score >=70 Category II = Score 51-69 Score for Hydrologic Functions Category III = Score 30-50 Score for Habitat Functions Category IV = Score < 30 TOTAL score for Functions Category based on SPECIAL CHARACTERISTICS of wetland I II Does not Apply Final Category (choose the "highest" category from above) Summary of basic information about the wetland unit Estuarine I I De ressional Natural Heritage Wetland I I Riverine 12 10 15 37 Mature Forest I Sloe Old Growth Forest Flats Coastal Lagoon Freshwater Tidal Interdunal None of the above ✓ Check if unit has multiple HGM classes present Wetland Rating Form — western Washington 1 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A Does the wetland unit being rated meet any of the criteria below? If you answer YES to any of the questions below you will need to protect the wetland according to the regulations regarding the special characteristics found in the wetland. Check L><st for Wetlands That May Need Add><t><onal Protection _YES TIQ ;` .�n. add><t;<on to the;; rotection-xecomtnendEd_for- rts_cat_e or SP1. Has the wetland unit been documented as a habitat for any Federally listed Threatened or Endangered animal or plant species (TIE species)? For the purposes of this rating system, "documented" means the wetland is on the appropriate state or federal database. SP2. Has the wetland unit been documented as habitat for any State listed Threatened or Endangered animal species? For the purposes of this rating system, "documented" means the wetland is on the appropriate state database. Note; Wetlands with State listed plant species are categorized as Category I Natural Heritage Wetlands see p. 19 of data form). SP3. Does the wetland unit contain individuals of Priorio) species listed by the WDFW for the state? SP4. Does the wetland unit have a local significance in addition to its functions? For example, the wetland has been identified in the Shoreline Master Program, the Critical Areas Ordinance, or in a local management plan as having special significance. To complete the next part of the data sheet you will need to determine the Hydro eomorphic Class of the wetland being rated. The hydrogeomorphic classification groups wetlands into those that function in similar ways. This simplifies the questions needed to answer how well the wetland functions. The Hydrogeomorphic Class of a wetland can be determined using the key below. Seep. 24 for more detailed instructions on classifying wetlands. Wetland Rating Form — western Washington 2 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A Classification of Wetland Units in Western Washington 1. Are the water levels in the entire unit usually controlled by tides (Le. except during floods)? F,71 NO — go to 2 F-1 YES — the wetland class is Tidal Fringe If yes, is the salinity of the water during periods of annual low flow below 0.5 ppt (parts per thousand)? YES — Freshwater Tidal Fringe NO — Saltwater Tidal Fringe (Estuarine) If your• wetlanP an be classified as a Freshwater idal Fringe use the forms for Riverine wetlands. If it is Saltwater Tidal Fringe it is rated as an Estuarine wetland. Wetlands that were called estuarine in the first and second editions of the rating system are called Salt Water Tidal Fringe in the Hydrogeomorphic Classification. Estuarine wetlands were categorized separately in the earlier editions, and this separation is being kept in this revision. To maintain consistency between editions, the term "Estuarine" wetland is kept. Please note, however, that the characteristics that define Category I and lI estuarine wetlands have changed (see p. ). 2. The entire wetland unit is flat and precipitation is the only source (>90%) of water to it. Groundwater and surface water runoff are NOT sources of water to the unit. WINO — go to 3 ❑ YES — The wetland class is Flats If your wetland can be classified as a "Flats" wetland, use the form for Depressional wetlands. 3. Does the entire wetland unit meet both of the following criteria? The vegetated part of the wetland is on the shores of a body of permanent open water (without any vegetation on the surface) at least 20 acres (8 ha) in size; At least 30% of the open water area is deeper than 6.6 ft (2 m)? F./-JNO — go to 4 F-1 YES — The wetland class is Lake -fringe (Lacustrine Fringe) 4. Does the entire wetland unit meet all of the following criteria? ✓ The wetland is on a slope (slope can be very gradual), The water flows through the wetland in one direction (unidirectional) and usually comes from seeps. It may flow subsurface, as sheetflow, or in a swale without distinct banks. ✓ The water leaves the wetland without being impounded? NOTE: Staface water does not pond in these type of wetlands except occasionally in vete small and shallow depressions or behind hammocks (depressions are usually <3ft diameter and less than 1 foot deep). E]NO - go to 5 AYES — The wetland class is Slope Wetland Rating Form—western Washington 3 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A 5, Does the entire wetland unit meet all of the following criteria? The unit is in a valley, or stream channel, where it gets inundated by overbank flooding from that stream or river The overbank flooding occurs at least once every two years. NOTE: The riverine unit can contain depressions that are filled with water when the riven is not flooding. F-�NO - go to 6 ❑YES — The metland class is Riverine 6. Is the entire wetland unit in a topographic depression in which water ponds, or is saturated to the surface, at some time during the year. This means that any outlet, ifpresent, is higher than the interior of the wetland. ❑NO — go to 7 ❑YES — The wetland class is Depressional 7. Is the entire wetland unit located in a very flat area with no obvious depression and no overbank flooding. The unit does not pond surface water more than a few inches. The unit seems to be maintained by high groundwater in the area. The wetland may be ditched, but has no obvious natural outlet. ❑NO — go to 8 ❑ YES — The wetland class is Depressional 8. Your wetland unit seems to be difficult to classify and probably contains several different HGM clases. For example, seeps at the base of a slope may grade into a riverine floodplain, or a small stream within a depressional wetland has a zone of flooding along its sides. GO BACK AND IDENTIFY WHICH OF THE HYDROLOGIC REGIMES DESCRIBED IN QUESTIONS 1-7 APPLY TO DIFFERENT AREAS IN THE UNIT (make a rough sketch to help you decide). Use the following table to identify the appropriate class to use for the rating system if you have several HGM classes present within your wetland. NOTE: Use this table only if the class that is recommended in the second column represents 10% or more of the total area of the wetland unit being rated. If the area of the class listed in column 2 is less than 10% of the unit; classify the wetland using the class that represents more than 90% of the total area. H 1VIClasses tiVrthrrt the vetlam wi .:bern ;idted HGMCIassYo Ue rrr Rahn Slope + Riverine Riverine Slope + Depressional- Depressional Slope + Lake -fringe Lake -fringe Depressional + Riverine along stream within boundary Depressional Depressional + Lake -fringe Depressional Salt Water Tidal Fringe and any other class of freshwater wetland Treat as ESTUARINE under wetlands with special characteristics If you are unable still to determine which of the above criteria apply to your wetland, or if you have more than 2 HGM classes within a wetland boundary, classify the wetland as Depressional for the rating. Wetland Rating Form — western Washington 4 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A =S Slope Wetlands � = - = Poiln>�s _ WATER Qi7AI,ITY 1FCTI`[GTIONS Indtcators that the vYetland unit functions to - t°"�y'ty��°re ,� '- :- • -� - ped` box) '_ S S 1. Does the wetland unit have the potential to improve water quality? (see p. 64) S S 1.1 Characteristics of average slope of unit: ❑Slope isl% or less (a 1% slope has a ]foot vertical drop in elevation for every 100 fi horizontal distance) points = 3 ❑Slope is 1% - 2% points = 2 0 ❑Slope is 2% - 5% points = 1 QSlope is greater than 5% points = 0 S S 1.2 The soil 2 inches below the surface (or duff layer) is clay or organic (Ilse NRCS Initions) 3 Mde ✓ YES= 3 points NO = 0 points S S 1.3 Characteristics of the vegetation in the wetland that hap sediments and pollutants: Figure 1 Choose the points appropriate for the description that hest fits the vegetation in the wetland. Dense vegetation means yon have trouble seeing the soil surface (>75% cover), and uncut means not grazed or mowed and plants are higher than 6 inches. ❑ Dense, uncut, herbaceous vegetation > 90% of the wetland area points = 6 Q Dense, uncut, herbaceous vegetation > 1/2 of area points = 3 3 ❑ Dense, woody, vegetation > '/2 of area points = 2 ❑ Dense, uncut, herbaceous vegetation > 1/4 of area points = 1 ❑ Does not meet any of the criteria above for vegetation points = 0 Aerial photo or map with vegetation polygons S Total for S 1 Add the points in the boxes above I s 6 S S 2. Does the wetland unit have the opportunity to improve water quality? (see p. 67) Answer YES if you know or believe there are pollutants in groundwater or surface water coming into the wetland that would otherwise reduce water quality in streams, lakes or groundwater downgradient from the wetland. Note which of the following conditions provide the sources of pollutants. A runt may have pollutants coming from several som•ces, but any single source would qualify as opportunity. ❑ Grazing in the wetland or within 150ft ❑ Untreated stormwater discharges to wetland ❑ Tilled fields, logging, or orchards within 150 feet of wetland ❑✓ Residential, urban areas, or golf courses are within 150 ft upslope of wetland multiplier ❑ Other 2 YES multiplier is 2 ONO multiplier is 1 S TOTAL -Water Quality Functions Multiply the score from SI by S2 2 Add score to table on p. Y Comments Wetland Rating Form—western Washington 11 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A S Slope Wetlands = � - _ �Po><nts I3YDR0);OGIC FUNCTIONS Indtcatoi;s°°that the �yetland uzut unctzons to �-ro,�ty-t ��°re , =xeduce #loodul aril sttearn eiosxen _ Pe7u°"I "' S 3. Does the wetland unit have the potential to reduce flooding and stream (see p,68) erosion? S S 3.1 Characteristics of vegetation that reduce the velocity of surface flows during storms. Choose the points appropriate for the description that best fit conditions in the wetland. (stems ofplants should be thick enough (usually > 1/81n), or dense enough, to remain erect during sin faceflows) Dense, uncut, rigid vegetation covers > 90% of the area of the wetland. points = 6 3 ✓ Dense, uncut, rigid vegetation > 1/2 area of wetland points = 3 Dense, uncut, rigid vegetation > 1/4 area points = 1 ❑ More than 1/4 of area is grazed, snowed, tilled or vegetation is not rigid points = 0 S S 3.2 Characteristics of slope wetland that holds back small amounts of flood flows: The slope wetland has small surface depressions that can retain water over at least 10% of its area. ❑✓ YES points = 2 2 ❑NO points = 0 S Add the points in the boxes above 1 ® 5 S S 4. Does the wetland have the opportunity to reduce flooding and erosion? seep. 70) Is the wetland in a landscape position where the reduction in water velocity it provides helps protect downstream property and aquatic resources from flooding or excessive and/or erosive flows? Note which of the following conditions apply. ❑ Wetland has surface runoff that drains to a river or stream that has flooding problems Other Wettand is upstream of property and aquatic resources (Puget Sound) multiplier (Answer NO if the major source of water is controlled by a reservoir (e.g. wetland is a seep 2 that is on the downstream side of a dam) ❑✓ YES multiplier is 2 ❑NO multiplier is 1 S TOTAL - Hydrologic Functions Multiply the score fi•om S 3 by S 4 Adel score to table on p. 1 10 Comments Wetland Rating Form — western Washington 12 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A These grsestons apply io weflands of all HGM classes ` Po><n�s (o�51y i score HABITAT FIINCTIOI�IS Indzcato;s that tinct fitncttc�ns to pzovxde unportan habitat pee,box) H 1. Does the wetland unit have the potential to provide habitat for many species? H 1.1 Vegetation structure (seep. 72) Figure 1 Check the types of vegetation classes present (as defined by Cowardin)- Size threshold for each class is % acre or more than 10% of the area if unit is smaller than 2.5 acres. =Aquatic bed =Emergent plants =Scrub/shrub (areas where shrubs have >30% cover) =Forested (areas where trees have >30% cover) If the unit has a forested class check if.• F,71 The forested class has 3 out of 5 strata (canopy, sub -canopy, shrubs, herbaceous, moss/ground-cover) that each cover 20% within the forested polygon Add the number of vegetation structures that qualms. If you have: =4 structures or more points = 4 Map of Cowardin vegetation classes =3 structures points = 2 02 structures points = 1 Q 1 structure points = 0 H 1.2. Hydroperiods (seep. 73) Figure 1 Check the types of ivater regimes (hydroperiods) present within the wetland. The water regime has to cover more than 10% of the wetland or % acre to count. (see text for descriptions of hydroperiods) =Permanently flooded or inundated =4 or more types present points = 3 =Seasonally flooded or inundated✓ 3 types present points = 2 =Occasionally flooded or inundated 2 types present point = 1 2 =Saturated only E] 1 type present points = 0 Permanently flowing stream or river in, or adjacent to, the wetland ✓= Seasonally flowing stream in, or adjacent to, the wetland = Lake -fringe wetland = 2 points =Freshwater tidal wetland = 2 points Map of hydroperiods H 1.3. Richness of Plant Species (seep. 75) Count the number of plant species in the wetland that cover at least 10 fe. (different patches of the same species can be combined to meet the size threshold) You do not have to name the species. Do not include Eurasian Milfoil, reed cana1)�grass, tople loosestrife, Canadian Thistle If you counted: > 19 species points = 2 List species below if you want to: Q 5 - 19 species points = 1 _ < 5 species points = 0 Total for page Wetland Rating Form — western Washington 13 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A H 1.4. Interspersion of habitats (seep. 76) Figure 1 Decide from the diagrams below whether interspersion between Cowardin vegetation classes (described in H 1. 1), or the classes and unvegetated areas (can include open water or mudflats) is high, medium, low, or none. O ®None = 0 points =Low = 1 point Moderate = 2 points 1 [riparian braided channels] ® High = 3 points NOTE; If you have four or more classes or three vegetation classes and open water the rating is always "high". Use map of Cowardin vegetation classes `H 1.5. Special Habitat Features; (seep. 77) Check the habitat features that are present in the wetland The number of checks is the number ofpoints youpttt into the next cohnnn. =Large, downed, woody debris within the wetland (>4in. diameter and 6 ft long). OStanding snags (diameter at the bottom > 4 inches) in the wetland =Undercut banks are present for at least 6.6 ft (2m) and/or overhanging vegetation extends at least 3.3 ft (lm) over a stream (or ditch) in, or contiguous with the unit, for at least 33 ft (1 Om) =Stable steep banks of fine material that might be used by beaver or muskrat for denning 2 (>30degree slope) OR signs of recent beaver activity are present (cut shrubs or trees that have not yet tunied grey/brown) =At least '/4 acre of thin -stemmed persistent vegetation or woody branches are present in areas that are permanently or seasonally inundated. (structures for egg -laying by amphibians) Invasive plants cover less than 25% of the wetland area in each stratum of plants NOTE: The 20% stated in earlyprintings of the manual on page 78 is an error. H L TOTAL Score - potential for providing habitat 7 N Add the scores rom HI.1, H1.2, H1.3, H1.4, HI.5 Comments Wetland Rating Form — western Washington 14 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A H 2. Does the wetland unit have the opportunity to provide habitat for many species? H 2.1 Buffers (seep. 80) Figure 1 Choose the description that best represents condition of buffer of wetland unit. The highest scoring criterion that applies to the wetland is to be used in the rating. See teat for definition of "undisturbed. " ❑ 100 in (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% of circumference. No structures are within the undisturbed part.of buffer. (relatively undisturbed also means no -grazing, no landscaping, no daily human use) Points = 5 ❑ 100 in (330 ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 50% circumference. Points = 4 ❑ 50 in (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water >95% circumference. Points = 4 ❑ 100 in (330ft) of relatively undisturbed vegetated areas, rocky areas, or open water > 25% 1 circumference, . Points = 3 ❑ 50 in (170ft) of relatively undisturbed vegetated areas, rocky areas, or open water for > 50% circumference. Points = 3 If buffer does not meet any of the criteria above ❑ No paved areas (except paved trails) or buildings within 25 in (80ft) of wetland > 95% circumference. Light to moderate grazing, or lawns are OK. Points = 2 ❑ No paved areas or buildings within 50rn of wetland for >50% circumference. Light to moderate grazing, or lawns are OK. Points = 2 ❑ Heavy grazing in buffer. Points =1 ❑ Vegetated buffers are <2m wide (6.6ft) for more than 95% of the circumference (e.g, tilled fields, paving, basalt bedrock extend to edge of wetland Points = 0. ❑✓ Buffer does not meet any of the criteria above. Points =1 Aerial photo showing buffers H 2.2 Corridors and Connections (seep. 81) H 2.2.1 Is the wetland part of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 150 ft wide, has at least 30% cover of shrubs, forest or native undisturbed prairie, that connects to estuaries, other wetlands or undisturbed uplands that are at least 250 acres in size? (dawns in riparian corridors, heavily used gravel roads, paved roads, are considered breaks in the corridor). ❑ YES = 4 points (go to H2.3) 7 NO = go to H 2.2.2 H 2.2.2 Is the wetland part of a relatively undisturbed and unbroken vegetated corridor (either riparian or upland) that is at least 50ft wide, has at least 30% cover of shrubs or 1 forest, and connects to estuaries, other wetlands or undisturbed uplands that are at least 25 acres in size? OR a Lake -fringe wetland, if it does not have an undisturbed corridor as in the question above? ❑YES = 2 points (go to H2.3) ❑✓ NO = H 2.2.3 H 2.2.3 Is the wetland: 7 within 5 mi (8km) of a brackish or salt water estuary OR ❑ within 3 mi of a large field or pasture (>40 acres) OR ❑within 1 mi of a lake greater than 20 acres? ✓ YES =1 point EINO = 0 points Total for page Wetland Rating Form —western Washington 15 August 2004 version 2 Updated with new WDFW definitions Oct, 2008 %ve.t k, ajd as, rNjsWe Lta n d A I -I Z3. oij , liabitals lj$IpLWMt)FW (Nep, Imov Ondcoolopkie E— q/JYVFFVpj4#4v hubliam, s,�nej Oe coomiles hs which the con befinind, in 'Y the PILY mpon alit.—/4v Li CLOpa.,ggawp A/ W h i c l i, Dt, ( I le 1`0 110 Wi i!l 8 IIri or i ly habi4il s H n c w it It i j 13' tll't( I 00m) of I I i e vie t1h, i i fl, un I t 7 AfO M c colmections &j, mf have to Im? rekifively uncylsllwhed, HAspeti Shinds. Pum, ux mixod stand's of upwi, greator than 0.4 lanai I acrc,)w HhWiversity Areas and Currldory Amos, of habilat'that arc rehitvely imporlmii to var4)iw s'! $cGies of r1a 'i vc fish Ona wit(ffirc (fill ciescriplions in fYDI,`;V PIIS,)Vor� jrj. .132),, Ilerha cea I is Ba [ds ; V 0 0441c, Size patchts of grass a n d fcjrt)�'; 011 S"10 11OW sOil'g 1"IM01rap , qac wt StanAs of at least 2 Ir" .,;pc6v,s,, forming a mulli-laymed canopy with ocusional SnIall ippardllgsw wi(It at least 20 lrv,vsAz,(8 freegJacre) -,- 81 alai (32 in) Ab ur > 200 yeays ofagm. Stands with, avermw diamelenq exu%ding 53 cm (21 in) cibb, crown coverimy be Ivss that IOGIA; Cr(AVA GovCr May be, leu, fliat decay, numbtas ol'snags, Ond quanfity of hirgo downed rvite6al is gwwraMy less than fluit Ibund sat old-growdi, 80.200 years old West Of the Cr=adz mrstw moregon white, Onlu Wood.tands Slands of putc ouig (.m: Oak/cOnifer 11,%300a tion's wlicre cano[voovernge of the o4k 000iponont j,4 important VNI RIDPWPIA.9 t1ey"Op, 158). M,Mparian-, The area w1jacenctol oc'lu,8610 Systerils With flowilig wuta that culitai"Ils der-ACON of both aquatic and terresArial ecosyslevu which mufuAy influence, me h other, =Wiestsjkle Prairies: 11VII-bacco"Lls, Plant cmmriuinitic�4 that oun 6011cr take the forM of a dry prairic or a wet prairle (fiX descripions 40 WDRYPHS relporl p, ) 61). =hnstnmm The combination of physicat, blalcigual, and chtmaical ptan wessus und cunditivn3 that inlevict (c) pj-oyidc Ftuxtional fire 116""fary vuqtkemenus Gor filstream fish anti M101t Nearshorv., Relad.vety um,distupbcd nousliore Imbitats. 'Mcsic include CciasNl Neurshore, Open Coust Neushorc, and 1"upt Snunc['Ncarshore� cule-Ithe aiqfinRhm qf),410fivel.). lawilsoirbed twe in ffTDFWrqpon:pjj. 107-169 andglassav)p in ApIxPle,MV, /1"), =C'a ves: A nat u ra,l ly ocuarri rIJ!, CaVi tyr [°LCj:,SS .7, Np()jt[, 01, systern o, r im orconnooted pame a.% u nd or I he ca ril h in tsui lsw ruck p ice, or Ober gCologi cal, rou liation s and iia hirge 011ough lo conta i n, at HCfiffs;, Orcoturtban'76 m (25 fi) high below 5000 ft- .-TsIfit.v I lsmyatap pasaaas Eireus of rock rubble ranging io ii%rcr4jgc qjvj 0, 15 - 2,0 ill (0.5 - 6,5 IT), counpumxl catr busaft, andesik% and/ur sedimcclary rock,Jncluding riprap Adcq and mine lilifinp—May, beassouiated with cliffis, [=,SIIW%gS and Logos: Ttx%,vq am, com,;idered stlings if Rizy are dead tea., dying and exhitsit m4ricient decay, to mmhju Onvity ex"warioxh/use: by, wildlifb, Prjohly'sn'ags have a, dianieter ill ba -cast heiglit of > 51 on (20 in) in westmi Wkudiingkm and arc, > 2 irk (16.5 R) ill he�gyht, Priority lop, illv-- 30 evii, ('l '2 in) iii dianleter, tit thc largest erld, u,nd > to r[I (20 R) knyg» 3 Hif wefland has 3 ar miore pdmity hat)Rms = 4 pahics ff welbuid has 2 priordly habilats 3 potnis, Olf wetiand IIs I pricrity habitat I point OI as I,liahilals- It poio4� Nwe,° A are Iry eh"finifilood apvioriv habital brae c)'Pv flof hu'Juded, in 11 is Weflatid Rafirgh"t-ma, - mman AVkisdd,ngton t6 Augusl:,2004 veiston 2 Updated with new WDFWderm,Wcams Oc[. 2008 Wetland name or number Wetland A H 2.4 Wetland Landscape (choose the one description of the landscape around the wetland that best fits) (seep. 84) ® There are at least3 other wetlands within'/2 mile, and the connections between them are relatively undisturbed (light grazing between wetlands OK, as is lake shore with some boating, but connections should NOT be bisected by paved roads, fill, fields, or other development. points = 5 0 The wetland is Lake -fringe on a lake with little disturbance and there are 3 other lake -fringe wetlands within''/2 mile points = 5 3 Q There are at least 3 other wetlands within'/2 mile, BUT the connections between them are disturbed points = 3 Q The wetland is Lake -fringe on a lake with disturbance and there are 3 other lake -fringe wetland within'/2 mile points = 3 0 There is at least 1 wetland within'/2 mile, points = 2 [� There are no wetlands within'/2 mile. points = 0 H 2. TOTAL Score - opportunity for providing habitat 8 Add the scores rom H2.1,H2.2, H2.3, H2.4 TOTAL for H 1 from page 14 7 Total Score for Habitat Functions — add the points for H 1, H 2 and record the result on 15 P. 1 Wetland Rating Form —western Washington 17 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wettand A CATEGORIZATION BASED ON SPECIAL CHARACTERISTICS Please determine if the wetland meets the attributes described below and circle the appropriate answers and Category. Wetland Type Category Check off any criteria that apply to the wetland. Circle the Category when the appropriate criteria are met. SC 1.0 Estuarine wetlands (seep. 86) Does the wetland unit meet the following criteria for Estuarine wetlands? [::]The dominant water regime is tidal, [::]Vegetated, and With a salinity greater than 0.5 ppt. ❑YES = Go to SC 1.1 NO ❑✓ SC 1.1 Is the wetland unit within a National Wildlife Refuge, National Park, National Estuary Reserve, Natural Area Preserve, State Park or Educational, Cat. I Environmental, or Scientific Reserve designated under WAC 332-30-151? 0 ❑YES = Category I ❑NO go to SC 1.2 SC 1.2 Is the wetland unit at least 1 acre in size and meets at least two of the following three conditions? ❑YES = Category I[I10 = Category II ❑ Cat. I ❑The wetland is relatively undisturbed (has no diking, ditching, idling, ❑Cat. II cultivation, grazing, and has less than 10% cover of non-native plant species. If the non-native Spartina spp, are the only species that cover more than 10% of the wetland, then the wetland should be given a dual ❑ Dual rating (I/11). The area of Spartina would be rated a Category H while the rating relatively undisturbed upper marsh with native species would be a I/II Category I. Do not, however, exclude the area of Spartina in determining the size threshold of 1 acre. ❑At least % of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un -grazed or un -mowed grassland. ❑The wetland has at least 2 of the following features: tidal channels, depressions with open water, or contiguous freshwater wetlands. Wetland Rating Form—western Washington 18 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A SC 2.0 Natural Heritage Wetlands (seep. 87) Natural Heritage wetlands have been identified by the Washington Natural Heritage [:]Cat. I Program/DNR as either high quality undisturbed wetlands or wetlands that support state Threatened, Endangered, or Sensitive plant species. SC 2.1 Is the wetland unit being rated in a Section/Township/Range that contains a Natural Heritage wetland? (this question is used to screen out most sites before you meed to contact WNHP/DNR) SMR information fi-om Appendix D Q or accessed fiom WNHP/DNR web site YES=— contact WNHP/DNR (see p. 79) and go to SC 2.2 NO SC 2.2 Has DNR identified the wetland as a high quality undisturbed wetland or as or as a site with state threatened or endangered plant species? =YES = Category I NO =not a Heritage Wetland SC 3.0 Bogs (seep. 87) Does the wetland unit (or any part of the unit) meet both the criteria for soils and vegetation in bogs? Use the hey below to identify if the wetland is a bog. If yoat answer yes you will still need to rate the tivetland based on its Junctions. 1. Does the unit have organic soil horizons (i.c, layers of organic soil), either peats or mucks, that compose 16 inches or more of the first 32 inches of the soil profile? (See Appendix B for a field key to identify organic soils)? Yes - go to Q. 3 [:j 0✓ No - go to Q. 2 2. Does the unit have organic soils, either peats or mucks that are less than 16 inches deep over bedrock, or an impermeable hardpan such as clay or volcanic ash, or that are floating on a lake or pond? 0 Yes - go to Q. 3 0✓ No - Is not a bog for purpose of rating 3. Does the unit have more than 70% cover of mosses at ground level, AND other plants, if present, consist of the "bog" species listed in Table 3 as a significant component of the vegetation (more than 30% of the total shrub and herbaceous cover consists of species in Table 3)? 0 Yes — Is a bog for purpose of rating 0 No - go to Q. 4 NOTE; If you are uncertain about the extent of mosses in the understory you may substitute that criterion by measuring the pH of the water that seeps into a hole dug at least 16" deep. If the pH is less than 5.0 and the "bog" plant species in Table 3 are present, the wetland is a bog. 1. Is the unit forested (> 30% cover) with sitka spruce, subalpine fir, western red cedar, western hemlock, lodgepole pine, quaking aspen, Englemann's spruce, or western white,pine, WITH any of the species (or combination of species) on the bog species plant list in Table 3 as a significant component of the ground cover (> 30% coverage of the total shrub/herbaceous cover)? 2.®YES = Category I No0 Is not a bog for purpose of rating Wetland Rating Form—westem Washington 19 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A Wetland Rating Form —western Washington 20 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 SC 4.0 Forested Wetlands (seep. 90) Does the wetland unit have at least 1 acre of forest that meet one of these criteria for the Department of Fish and Wildlife's forests as priority habitats? If you answer yes you will still need to rate the wetland based on its functions. . Fj Old-growth forests: (west of Cascade crest) Stands of at least two tree species, forming a multi -layered- canopy with occasional small openings; with at least 8 trees/acre (20 trees/hectare) that are at least 200 years of age OR have a diameter at breast height (dbh) of 32 inches (81 cm) or more. NOTE: The criterion for dbh is based on measurements for upland forests. Two -hundred year old trees in wetlands will often have a smaller dbh because their growth rates are often slower. The DFW criterion is and "OR" so old-growth forests do not necessarily have to have trees of this diameter. Fj Mature forests: (west of the Cascade Crest) Stands where the largest trees are 80 — 200 years old OR have average diameters (dbh) exceeding 21 inches (53cm); crown cover may be less that 100%; decay, decadence, numbers of snags, and quantity of large downed material is generally less than that found in old-growth. Cat. I � YES= Category I NO anot a forested wetland with special characteristics SC 5.0 Wetlands in Coastal Lagoons (seep. 91) Does the wetland meet all of the following criteria of a wetland in a coastal lagoon? The wetland lies in a depression adjacent to marine waters that is wholly or partially separated from marine waters by sandbanks, gravel banks, shingle, or, less frequently, rocks ❑ The lagoon in which the wetland is located contains surface water that is saline or brackish (> 0.5 ppt) during most of the year in at least a portion of the lagoon (needs to be measured near the bottom) YES = Go to SC 5.1 NO E] not a wetland in a coastal lagoon SC 5.1 Does the wetland meets all of the following three conditions? ❑The wetland is relatively undisturbed (has no diking, ditching, filling, cultivation, grazing), and has less than 20% cover of invasive plant species (see list of invasive species on p. 74). E] At least 3/4 of the landward edge of the wetland has a 100 ft buffer of shrub, forest, or un -grazed or un -mowed grassland. Fj Cat. I ❑The wetland is larger than 1/10 acre (4350 square feet) YES = Category I DNO = Category II DCat. II Wetland Rating Form —western Washington 20 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Wetland name or number Wetland A SC 6.0Interdunal Wetlands (seep. 93) Is the wetland unit west of the 1889 line (also called the Western Boundary of Upland Ownership or WBUO)? ❑YES - go to SC 6.1 NO Q✓ not an interdunal wetland for rating If you answer yes you will still need to rate the wetland based on its functions. In practical terms that means the following geographic areas: ❑ Long Beach Peninsula- lands west of SR 103 ❑ Grayland-Westport- lands west of SR 105 ❑ Ocean Shores-Copalis- lands west of SR 115 and SR 109 SC 6.1 Is the wetland one acre or larger, or is it in a mosaic of wetlands that is once acre or larger? ❑ YES = Category H ❑ NO — go to SC 6.2 Cat. II ❑ SC 6.2 Is the unit between 0.1 and 1 acre, or is it in a mosaic of wetlands that is between 0.1 and 1 acre? ❑YES = Category III Wetland Rating Form— western Washington 21 August 2004 version 2 Updated with new WDFW definitions Oct. 2008 Cat. III❑ WETLAND DETERMINATION DATA FORM — Western Mountains, Valleys, and Coast Region Project/Site: Hillman - Sierra Place City/county: Edmonds/ Snohomish County Sampling Date: 3/11 Applicant/Owner: Lin Hillman. State: WA Sampling Point: S1 Investigator(s): A. Bachman Section, Township, Range: S24, T27N, R3E, W.M. Landform (hillslope, terrace, etc.): Slope Local relief (concave, convex, none): None Slope (%): 15 Subregion (LRR): LRR-A Let: Long: Datum: Soil Map Unit Name: Alderwood soils, 15 to 25 percent slopes NWI classification: None Are climatic/ hydrologic conditions on the site typical for this time of year? Yes ✓ No (If no, explain in Remarks.) Are Vegetation Soil or Hydrology _ significantly disturbed? Are "Normal Circumstances" present? Yes _ ✓ ` No Are Vegetation Soil or Hydrology naturally problematic? (If needed, explain any answers in Remarks.) SUMMARY OF FINDINGS — Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes ✓ No— — Is the Sampled Area Hydric Soil Present? Yes— ✓ No— _ ✓ Wetland Hydrology Present? Yes ✓ No within a Wetland? Yes No Remarks: VEGETATION — Use scientific names of plants. Tree Stratum (Plot size: ) 1. Alnus rubra Absolute Dominant Indicator -% .Cover Species? Status 30 Y Fac Dominance Test worksheet: Number of Dominant Species That Are OBL, FACW, or FAC: 2 (A) Total Number of Dominant Species Across All Strata: 3 (B) of Dominant Species That Are OBL, FACW, or FAC: 66 (A/B) 2, 3• 4. Sapling/Shrub Stratum (Plot size: 1. Rubus spectabilis 30Percent ) 35 = Total Cover Y Fac+ Prevalence Index worksheet: Total % Cover of: Multiply by: OBL species x 1 = FACW species x 2 = FAC species x 3 = FACU species x4= UPL species x5= Column Totals: (A) (B) Prevalence Index = B/A = 2. Rubus armeniucus 45 Y FacU 3. 4. 5. 80 = Total Cover Herb Stratum (Plot size: ) 1. 2. 3. 4, Hydrophytic Vegetation Indicators: ✓ Dominance Test is >50% Prevalence Index Is 53.0' Morphological Adaptations' (Provide supporting data in Remarks or on a separate sheet) — Wetland Non -Vascular Plants' Problematic Hydrophytic Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic, 5, 6, 7, 8. 9. 10. 11. Woody Vine Stratum (Plot size: 1 ) = Total Cover Hydrophytic Vegetation Present? Yes ✓ No 2 = Total Cover % Bare Ground in Herb Stratum Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast — Interim Version SOIL Sampling Point: S 1 Profile Description: (Describe to the depth needed to document the indicator or confirm the absence of indicators.) Depth Matrix Redox Features Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) (inches) Color (moist) % Color (moist) % Type Loci Texture Remarks 0-12 10YR 2/1 1, 2, 4A, and 413) mucky gr. salo saturated 12-18+ 10YR 3/1 Salt Crust (1311) _ gr. salo saturated 'Type: C=Concentration, D=De letion, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Soils3: — Histosol (Al) — Sandy Redox (S5) _ 2 cm Muck (A10), _ Histic Epipedon (A2) — Stripped Matrix (S6) _ Red Parent Material (TF2) _ Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) _, Other (Explain in Remarks) _ Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) _ Surface Soil Cracks (136) Depleted Below Dark Surface (A11) Depleted Matrix (F3) _ Inundation Visible on Aerial Imagery (137) Thick Dark Surface (Al2) Redox Dark Surface (F6) 'Indicators of hydrbphytic vegetation and ✓ Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (if present): _ Depth (inches): Type: Water Table Present? Yes ✓ No Depth (inches): Depth (Inches): Hydric Soil Present? Yes___�L No Remarks: Wetland Hydrology Present? Yes ✓ No Includes capillary fringe) HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) ✓ Surface Water (Al) — Water -Stained Leaves (139) (except MLRA _ Water -Stained Leaves (139) (MLRA 1, 2, ✓ High Water Table (A2) 1, 2, 4A, and 413) 4A, and 413) ✓ Saturation (A3) Salt Crust (1311) _ Drainage Patterns (1310) _ Water Marks (131) Aquatic Invertebrates (1313) _ Dry -Season Water Table (C2) _ Sediment Deposits (132) _ Hydrogen Sulfide Odor (C1) _ Saturation Visible on Aerial Imagery (C9) _ Drift Deposits (133) ` Oxidized Rhizospheres along Living Roots (C3) _ Geomorphic Position (D2) Algal Mat or Crust (134) Presence of Reduced Iron (C4) — Shallow Aqultard (133) _ Iron Deposits (135) _ Recent Iron Reduction In Tilled Soils (C6) FAC -Neutral Test (135) _ Surface Soil Cracks (136) _ Stunted or Stressed Plants (D1) (LRR A) Raised Ant Mounds (D6) (LRR A) _ Inundation Visible on Aerial Imagery (137) _ Other (Explain in Remarks) Frost -Heave Hummocks (D7) _ Sparsely Vegetated Concave Surface (138) Field Observations: Surface Water Present? Yes ✓ No— _ Depth (inches): Water Table Present? Yes ✓ No Depth (inches): Saturation Present? Yes ✓ No Depth (inches): Wetland Hydrology Present? Yes ✓ No Includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous Inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast —'Interim Version WETLAND DETERMINATION DATA FORM — Western Mountains, Valleys, and Coast Region Project/Site: Hillman -Sierra Place City/County: Edmonds/ Snohomish County Sampling Date: 3/11 Applicant/Owner: Lin Hillman. State: WA v Sampling Point: S2 Investigator(s): A. Bachman Section, Township, Range: S24, T27N, RK, W.M. Landform (hlllslope, terrace, etc.): Slope Local relief (concave, convex, none): None Slope (%): 15 Subregion (LRR): LRR-A Let: Long: Datum: Soil Map Unit Name: Alderwood soils, 15 to 25 percent slopes NWI classification: None Are climatic / hydrologic conditions on the site typical for this time of year? Yes ✓ No (If no, explain In Remarks.) Are Vegetation Soil or Hydrology_ _ significantly disturbed? Are "Normal Circumstances" present? Yes ^ ✓ _ No Are Vegetation Soil or Hydrology naturally problematic? (if needed, explain any answers in Remarks.) SUMMARY OF FINDINGS — Attach site map showing sampling point locations, transects, important features, etc. Hydrophytic Vegetation Present? Yes No _ ✓ _ is the Sampled Area Hydric Soil Present? Yes _ _ No _ ✓ _ ✓ within a Wetland? Yes No %(Wetland Hydrology Present? Yes No 3. Pseudotsuga menzeisii 10 N FacU Remarks: VEGETATION — Use scientific names of plants. Tree Stratum (Piot size: ) 1. Acer macrophylum Absolute % Cover 25 Dominant Indicator Species? Status Y FacU Dominance Test worksheet: Number of Dominant Species 2 That Are OBL, FACW, or FAC: (A) Total Number of Dominant Species Across All Strata: 4 (B) Percent of Dominant Species That Are OBL, FACW, or FAC: 50 (A/13)• 2. Thuja plicata 15 Y Fac 3. Pseudotsuga menzeisii 10 N FacU 4. Alnus rubra 10 N Fac Seplina/Shrub Stratum (Plot size: ) 1, Rubus spectabilis 60 35 = Total Cover Y Fac+ Prevalence Index worksheet: Total % Cover of., Multiply by: 2, Rubus armeniucus 45 Y FacU 3. OBL species x 1 = FACW species x2= FAC species x 3 = FACU species x4= UPL species x 5 = Column Totals: (A) (B) Prevalence Index = B/A = 4. 5, 80 = Total Cover Herb Stratum (Plot size: ) 1' 2. 3. 4, Hydrophytic Vegetation Indicators: _ Dominance Test is >50% Prevalence Index is 53.0' Morphological Adaptations' (Provide supporting data In Remarks or on a separate sheet) _ Wetland Non -Vascular Plants' Problematic Hydrophytic Vegetation' (Explain) 'Indicators of hydric soil and wetland hydrology must be present, unless disturbed or problematic. 5, 6, 7, 8. 9 10.' 11. Woody Vine Stratum (Plot size: ) 1 • = Total Cover Hydrophytic Vegetation Present? Yes No ✓ 2 = Total Cover % Bare Ground in Herb Stratum Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast— Interim Version SOIL Sampling Point: S2 Profile Description: (Describe to the depth needed to document the Indicator or confirm the'absence of Indicators.) Depth Matrix Redox Features Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) (Inches) Color (moist) % Color (moist) % TypeL Loc' Texture Remarks 0-4 10YR 3/2 1, 2, 4A, and 413) gr. sandy loam 4-18+ 1 OYR 3/3 Salt Crust (B11) _ gr. sandy loam _ Water Marks (131) Aquatic Invertebrates (1313) _ Dry -Season Water Table (C2) 'Type: C=Concentration, D=De letlon, RM=Reduced Matrix, CS=Covered or Coated Sand Grains. 2Location: PL=Pore Lining, M=Matrix. Hydric Soil Indicators: (Applicable to all LRRs, unless otherwise noted.) Indicators for Problematic Hydric Solis3: _ Histosoi (Al) — Sandy Redox (S5) _ 2 cm Muck (A10) Histic Epipedon (A2) — Stripped Matrix (S6) _ Red Parent Material (TF2) _V Black Histic (A3) Loamy Mucky Mineral (F1) (except MLRA 1) _ Other (Explain in Remarks) _ Hydrogen Sulfide (A4) Loamy Gleyed Matrix (F2) Inundation Visible on Aerial Imagery (137) _ Depleted Below Dark Surface (A11) Depleted Matrix (F3) _ Sparsely Vegetated Concave Surface (138) Thick Dark Surface (Al2) Redox Dark Surface (F6) 31ndicators of hydrophytic vegetation and Sandy Mucky Mineral (S1) Depleted Dark Surface (F7) wetland hydrology must be present, Sandy Gleyed Matrix (S4) Redox Depressions (F8) unless disturbed or problematic. Restrictive Layer (If present): Water Table Present? Yes No Depth (inches): Type: Saturation Present? Yes No Depth (Inches): Wetland Hydrology Present? Yes No ✓ Hydric Soil Present? Yes No ✓ Remarks: HYDROLOGY Wetland Hydrology Indicators: Primary Indicators (minimum of one required: check all that apply) Secondary Indicators (2 or more required) _ Surface Water (Al) _ Water -Stained Leaves (139) (except MLRA _ Water -Stained Leaves (139) (MLRA 1, 2, _ High Water Table (A2) 1, 2, 4A, and 413) 4A, and 4B) Saturation (A3) Salt Crust (B11) _ Drainage Patterns (1310) _ Water Marks (131) Aquatic Invertebrates (1313) _ Dry -Season Water Table (C2) _ Sediment Deposits (132) ^ Hydrogen Sulfide Odor (C1) — Saturation Visible on Aerial Imagery (C9) _ Drift Deposits (133) _ Oxidized Rhlzospheres along Living Roots (C3) _ Geomorphic Position (D2) Algal Mat or Crust (134) Presence of Reduced Iron (C4) _ Shallow Aquitard (D3) _ Iron Deposits (135) _ Recent Iron Reduction In Tilled Soils (C6) FAC -Neutral Test (D5) _ Surface Soil Cracks (136) __. Stunted or Stressed Plants (D1) (LRR A) Raised Ant Mounds (D6) (LRR A) Inundation Visible on Aerial Imagery (137) _ Other (Explain in Remarks) Frost -Heave Hummocks (D7) _ Sparsely Vegetated Concave Surface (138) Field Observations: Surface Water Present? Yes No — _ Depth (inches): Water Table Present? Yes No Depth (inches): Saturation Present? Yes No Depth (inches): Wetland Hydrology Present? Yes No ✓ includes capillary fringe) Describe Recorded Data (stream gauge, monitoring well, aerial photos, previous inspections), if available: Remarks: US Army Corps of Engineers Western Mountains, Valleys, and Coast— Interim Version