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CRA20170221 determination and maps.pdfCITY OF EDMONDS 121 51h Avenue North, Edmonds WA 98020 Phone: 425.771.0220 e Fax: 425.771.0221 • Web: www.edmondswa DEVELOPMENT SERVICES DEPARTMENT • PLANNING DIVISION ""plc. 1 g9m Critical Area Determination (CRA20170221) Based on a review and inspection of the subject site, staff has determined that one or more critical areas are located on or near the site. Critical areas are ecologically sensitive or hazardous areas that are protected in order to maintain their functions and values. Site Location 19015 Olympic View Drive Tax Account Number Not yet issued (Lot B of PLN20140075) Property Owner Merin Mione Applicant Merin Mione Critical Area(s) Present ❑ Wetlands (ECDC 23.50) ❑ Frequently Flooded Areas (ECDC 23.70) ® Geologically Hazardous Areas (ECDC 23.80) ® Erosion Hazard Areas ® Landslide Hazard Areas ❑ Seismic Hazard Areas ❑ Fish & Wildlife Habitat Conservation Areas (ECDC 23.90) ❑ Streams Site Description The recently subdivided vacant site slopes gradually down east -west toward Olympic View Drive. There are short, steeper portions of the slope adjacent to the eastern and western edges of the parcel. According to NRCS soils data, the area is underlain by Alderwood Gravelly sandy loams, 15 - 25% slopes. The bulk of the site has a slope in excess of a 15% grade; those areas are identified as a potential erosion hazards. The two steeper portions of slope in excess of 40% are considered to be potential landslide hazard areas. The geotechnical report submitted with the associated short plat dated January 11, 2017 (attached) describes these conditions. What does this mean? The critical area regulations are only triggered when an alteration is proposed to a critical area or its buffer. However, once an alteration in or near critical area is proposed, critical area studies and City review and approval may be required. What is an 'Alteration'? According to Section 23.40.005 of the Edmonds Community Development Code (ECDC): "Alteration" means any human -induced action which changes the existing conditions of a critical area or its buffer. Alterations include, but are not limited to: grading, filling; dredging; draining; channelizing; cutting, pruning, limbing or topping, clearing, relocating or removing vegetation; applying herbicides or pesticides or any hazardous or toxic substance; discharging pollutants; paving, construction, application of gravel; modifying for surface water management purposes; or any other human activity that changes the existing landforms, vegetation, hydrology, wildlife or wildlife habitat value of critical areas. Mike Clugston, AICP, Associate Planner, January 8, 2018 Name, Title Signature Date Cited sections of the Edmonds Community Development Code (ECDC) can be found at h ttp://www. codepublishing. com/WA/Edmonds Environmentally Critical Areas General Provisions (ECDC 23.40) Wetlands (ECDC 23.50) Frequently Flooded Areas (ECDC 23.70) Geologically Hazardous Areas (ECDC 23.80) Fish and Wildlife Habitat Conservation Areas (ECDC 23.90) Building permits — Earth Subsidence and Landslide Hazard Areas (ECDC 19.10) City of Edmonds GIS map tool with approximate location of critical areas: http://maps. edmondswa.gov Page 12 C:, _ 0t ._.^I tl 0 ...�.... _..�.�.. d 0 .00 £Z£L m � IfPfi1 itY a 3 N ..,. y.1� �� Y yYY N w a z� H u �u f )p 1,30.10 µ, oni t�7•vr,.::" tl ....r� .. _�e..�.N....,.-..._ � U Ld �a q � $ ,__.�_,. � r"ww^m^«� ��r re'�'ti�- .. _ � � � o��d'm .� .....,�LSY Ire',,: * f✓" '�r��Wfiynv� `��'��� +.. I fd Qom y 30 � nX'r en a z n - 130.82' ��-- a I U p-b�ry w� III N N a § m rd E N +w m z m 0 BS ry � N J 3 Gf o l( z o z ..,...,. .. �,�,,, ._ �_.-.e—, _ ...4._........_ .... of LB l k p L9 LEZ 3 L L ZO I N "i' f "" _ "- M• tl � m nzolo s .WJ�O pl7 .x; ad M31A d .....�� OIL n u., ppy4 4 CJ Y 'Slyi O'HIZ 3.LZ6LON_....��..__.___��.�0.10 II >>�- u l W 7 lYld Z Li 9Z 3 Ll.Z0.10 N H � ` F 3 poz w 3 W Z z. m rn z zo o k� o- d5 w 7i'"w az w o �r3N F�i O m M W a 4 � � 4 %'I V% Dca o dl 6a S o in ^' 0 W z LLo o �G+t p'6 - C'�.Y, i/s! ? Z J a a w ' a s kw` O LL. BE LOo g� w U 0 a a y 3 3 O d LL- Yn' cxi!S o m m F aC�a Q Q to o C \ a ¢$"a' ta` N - J w a m Z p a ~ _ W Z w LL o W U (n d N ® x 0 a o ?Or k qq a r W #20 Critical Areas File #: - 2� ❑ Initial Determination - $100 Subsequent Determination - $60 Date Received: l l Date Mailed to Applicant: The purpose of this checklist is to enable City staff to determine whether any critical areas and/or buffers are located on or adjacent to the subject property. Critical areas, such as wetlands, streams and steep slopes, are ecologically sensitive or hazardous areas that are regulated to protect their functions and values. The City's critical area regulations are contained within Edmonds Community Development Code (ECDC) Chapters 23.40 through 23.90. Property Owner's Authorization City of Edmonds Development Services Department Planning Division Phone: 425.771.0220 www.edmondswa.gov A property owner, or an authorized representative, must fill out the checklist, sign and date it, and submit it to the City. Staff will review the checklist, conduct a site visit, and make a determination of whether there are critical areas and/or critical area buffers on or near the site. If a "Critical Area Present" determination is issued, a report addressing the applicable critical area requirements of ECDC Chapters 23.40'through 23.90 may be required depending on the scope of the proposed activity. By my signature, I certify that the information and exhibits herewith submitted are true and correct to the best of my knowledge and grant my permission for the public officials and the staff of the City of Edmonds to enter the subject property for the purposes of inspection attendant to this application. The undersigned owner, and his/her/its heirs, and assigns, in consideration on the pro ssing'; of the application agrees to release, indemnify, defend and hold the City of Edmonds harmless from any and a damages, includii .reasonable attorney's fees, arising from any action or infraction based in whole or part upon false, 11 i leading, zt cc ra tc o incomplete information furnished by the applicant, his/her/its agents or employees.' , SIGNATURE OF OWNER --�-414VL Owner Name . t, Email address: DATE Applicant/Agent: Q�, A'i— Name Street Address Telephone: Address: State Zip Revised on 114117 P20 - Critical Areas Checklist Page 1 of 2 CA File No: CPA -Zo i '`" W&Z L # io Critical Areas Checklist Site Information 1. Site Address/Location: � 0 2. Property Tax Account Number: 3; Approximate Site Size (acres or square feet), 4. Is this site currently developed? ❑ Yes o If yes, how is the site developed? 5. Describe the general site topography. Check all that apply. El Flat to Rolling: No slope on/adjacent to the site or slopes generally less than 15% (a vertical rise of 10-feet over a'horizontal distance of`66-feet). ><Vloderate: Slopes present, on/ to site of more than 15% and less than 40% (a vertical rise of 10-feet over a horizontal distance of 25 to 66-feet). ❑ Steep: Slopes of greater than 40% present on/ adjacent to site (a vertical rise of 10-feet over a horizontal distance of less than 225-feet). 6. Have there been landslides on or near the site in the past? ❑ Yes 1R<0 If yes, please describe: 7. Site contains areas of year-round standing water? ❑ Yes (approx. depth: ))1_110 8. Site contains areas of seasonal standing water? ❑ Yes (approx. depth: ) No If yes, what season(s) of the year? 9,, Site is in the floodway or floodplain of a water course? ❑ Floodway ❑ Floodplain 10. Site contains a creek or an area where water flows across the grounds surface? ❑ Yes 40 If yes, are flows year-round or seasonal? ❑ Year-round ❑ Seasonal (time of year: ) 11. Obvious wetland is present on site? ❑ Yes No --- —-------------- -. ,...-,. --_. For City Staff Use Only 1 Zonmg S — Z 3. SCS mapped soil type(s)): r . mac 3. Critical Areas inv ntory or C.A. map indicates Critical Area on site: #�6&. uo r "la 4. Site within designated North Edmonds Earth Subsidence and Landslide Hazard Area (ESHLA)? w DETERMINATION " ITIC L AREAS PRESENT WAIVER Reviewed by:_ .date: Revised on 114117 P20 - Critical Areas Checklist Page 2 of 2 Mione Short Plat January 11, 2017 19011 Olympic View Drive (Parcel # 00434600007800) Project #14012 Edmonds, Washington rtical Areas Report for Geologically Hazardous Areas Mione Short Plat Parcel # 00434600007800 19011 Olympic View Drive ta� Edmonds, Washington The purpose of this report to fulfill the requirements of the Edmonds Community Development Code (ECDC) as set forth in previous planning department reviews. To ensure completeness, this report will include excerpts of the ECDC, specifically ECDC 23.80.50, and our responses will follow each code item or series of items, as appropriate. From ECDC 23.80.50 Critical area report requirements for geologically hazardous areas are generally met through submission to the Director of one of more geotechnical engineering reports. In addition to the general critical area report requirements of section 23.40.90, critical area reports for geologically hazardous areas must meet the requirements of this Section and ECDC Chapters 19.05 and 18.30 as applicable. Critical area reports for two or more typos of critical areas must meet the report requirements for each relevant type of critical area. Geotechnical report(s) submitted for the purpose of critical areas reviews are required as necessary in addition to reports, data and other information mandated per ECDC Titles 18 and 19. A. Preparation by a Qualified Professional. (details omitted for the sake of brevity) Response; Andrew L. Glandon, LEG, CPESC is a licensed engineering geologist in the State of Washington (License #2689) with 18 years of professional experience as an engineering geologist in the Puget Sound region. Mr. Glandon is also a Certified Professional in Erosion and Sediment Control (CPESC #3370), as administered by EnviroCert International, Inc.®. Mr. Glandon's credentials fulfill the requirements for a Qualified Professional. B. Area Addressed in Critical Area Report. The following areas shall be addressed in a critical area report for geologically hazardous areas: 1. The project area of the proposed activity; and 2. All geologically hazardous areas within 200 feet of the project area or that have potential to be affected by the proposal gLsponse: There was no observed evidence of current or past landslide activity on or within 200 feet of the subject property. The approximate location of the landslide hazard area on the subject property is shown in the attached figure titled "Landslide Hazard Areas and Buffers". These are the areas defined by ECDC 23.80.20 B (2), which are any areas with a slope of 40 percent or greater that is in excess of 10 feet in vertical height.. None of the other landslide hazard area criteria was observed. Based on our knowledge of the area and our review of the geologic and SOUTH FORK GEOSCIENCES, PLLC Page 1 PO Box 1 275 NORTH BEND, WA 98045 425-831-2023 1 NQRE WC9)SC EO clqm Mione Short Plat January 11, 2017 19011 Olympic View Drive (Parcel # 00434600007800) Project #14012 Edmonds, Washington other mapping resources referenced in our geotechnical report (SFG, April 2014), it is our opinion that there are not any off -site critical areas that are likely to impact the proposed development. C. Geological Hazards Assessment. A critical area report for a geologically hazardous area shall contain an assessment of geological hazards including the following site- and proposal - related information at a minimum. 1. Site and Construction Plans. The report shall include a copy of the site plans for the proposal showing: a. The type and extent of geologic hazard areas, any other critical areas, and buffers on, adjacent to, within 200 feet of, or that are likely to impact the proposal; b. Proposed development, including the location of existing and proposed structures, fill, storage of materials, and drainage facilities, with dimensions indicating distances to the floodplain, if available; c. The topography, in two -foot contours, of the project area and all hazard areas addressed in the report; and d. Clearing limits; Response. - As previously stated, based on our knowledge of the area and our review of the geologic and other mapping resources referenced in our geotechnical report (SFG, April 2014), it is our opinion that there are not any off -site critical areas that are likely to impact the proposed development. The referenced engineering plans for the project show the information set forth inC.1.b,c&d. Assessment of Geological Characteristics. The report shall include an assessment of the geologic characteristics of the soils, sediments, and/or rock of the project area and potentially affected adjacent properties, and a review of the site history regarding landslides, erosion, and prior grading. Soils analysis shall be accomplished in accordance with accepted classification systems in use in the region. The assessment shall include, but not be limited to: a. A description of the surface and subsurface geology, hydrology, soils, and vegetation found in the project area and in all hazard areas addressed in the report; b. A detailed overview of the field investigations; published data, and references; data and conclusions from past assessments of the site, and site specific measurements, test, investigations, or studies that support the identification of geologically hazardous areas; and c. A description of the vulnerability of the site to seismic and other geologic events; Response. All of these items were set forth in the referenced geotechnical report for the project (SFG, April 2014). 3. Analysis of Proposal. The report shall contain a hazards analysis including a detailed description of the project, its relationship to the geologic hazard(s), and its potential SOUTH FORK GEOSCIENCES, PLLC Page 2 PO Box 1 275 NORTH BEND, WA 98045 425-831-2023 1 P�lQNE @S G O C0M Mione Short Plat January 11, 2017 19011 Olympic View Drive (Parcel # 00434600007800) Project #14012 Edmonds, Washington impact upon the hazard area, the subject property, and affected adjacent properties; and 4. Minimum Buffer and Building Setback The report shall make a recommendation for the minimum no -disturbance buffer and minimum building setback from any geologic hazard based upon the geotechnical analysis. Response: Between this report and our referenced geotechnical report, it is our opinion that Item #3 above has been fulfilled. The landslide hazard areas and the 10-foot buffers are shown in the attached figure titled "Landslide Hazard Areas and Buffers". It is our opinion that the 10-foot buffers provide adequate mitigation for the landslide hazard areas and no other setbacks are required. D. Incorporation of Previous Study. Where a valid critical areas report has been prepared within the last five years for a specific site, and where the proposed land use activity and surrounding site conditions are unchanged, said report may be incorporated into the required critical area report. The applicant shall submit a hazards assessment detailing any changed environmental conditions associated with the site. Re don e, To our knowledge, there are not any previous studies to incorporate into this study.. E. Mitigation of Long -Term Impacts. When hazard mitigation is required, the mitigation plan shall specifically address how the activity maintains or reduces the pre-existing level of risk to the site and adjacent properties on a long-term basis (equal to or exceeding the projected lifespan of the activity or occupation). Proposed mitigation techniques shall be considered to provide long-term hazard reduction only if they do not require regular maintenance or other actions to maintain their function. Mitigation may also be required to avoid any increase in risk above the pre-existing conditions following abandonment of the activity. Response: The hazard mitigation that is required by the ECDC is buffering and setback of the landslide hazard area, which does not require any maintenance to maintain function. As such, it is our opinion that additional mitigation for long-term impacts is not warranted. F. Additional Technical Information Requirements for Erosion and Landslide Hazard Areas. In addition to the basic critical area report requirements for geologically hazardous areas provided in subsections A through E above, technical information for erosion and landslide hazard areas shall meet the requirements of ECDC 19.05 and include the following information at a minimum. 1. Site Plan. The critical area report shall include a copy of the site plan for the proposal showing: a. The height of slope, slope gradient, and cross section of the project area; b. The location of springs, seeps, or other surface expressions of ground water on or within two hundred feet of the project area or that have potential to be affected by the proposal; c. The location and description of surface water runoff features; SOUTH FORK GEOSCIENCES, PLLC Page 3 PO Box 1 275 NORTH BEND, WA 98045 i 425-831-2023 1 "a,NDRF'v' @$ G c)._ (aM Mione Short Plat January 11, 2017 19011 Olympic View Drive (Parcel # 00434600007800) Project #14012 Edmonds, Washington Mons a. The referenced civil engineering plans for the project show the slopes and 2-foot contours of the project site. The slope areas of focus range from approximately 2.25H:1V to 1.4H:1V (Horizontal:Vertical), or 44 to 71 percent. Since we do not anticipate excessively deep foundation excavations in association with development of the western lot, it is our opinion that a cross section of the slope is not warranted. b. & c. No springs, seeps, other surface expressions of groundwater, or surface water runoff features were noted in our prior site reconnaissance. As such, these features are not shown on the civil engineering plans for the project. Hazards Analysis. The hazards analysis component of the critical areas report shall specifically include; a. A description of the extent and type of vegetative cover; b. A description of the subsurface conditions based on data from site specific explorations; c. Descriptions of surface and ground water conditions, public and private sewage disposal systems, fills and excavations, and all structural improvements; Rest onset It is our opinion that for the sake of a short plat subdivision, all of these items were adequately assessed and described in the referenced geotechnical report for the project (SFG, April 2014). d. An estimate of slope stability and the effect that construction and placement of structures will have on the slope over the estimated life of the structure; Response: The entire site is underlain by medium dense to dense Vashon advance outwash sediments. These sediments were over -consolidated by the Vashon glacial ice sheet and there are not adverse geologic conditions or ground water conditions on or near the site. As such, it is our opinion that the likelihood of a deep-seated, rotational failure on or adjacent to the subject property is low. The "landslide hazard areas" are only areas that exceed the slope geometry criteria, and much of these areas were created by previous grading. It is our opinion that the observed stability over the life of the existing structure, approximately 67 years, is adequate evidence of the slope stability for the future, since the proposed construction will not be within or impact the "landslide hazard areas". It is our opinion that the new structures and features will not negatively impact the slope stability and the 10-foot buffer provides adequate mitigation. e, An estimate of the bluff retreat rate that recognizes and reflects potential catastrophic events such as seismic activity or a one -hundred year storm event; "espouse. A bluff retreat rate estimation is not applicable to the subject property or a slope of this nature, since the geometry is not extreme and there is not an ongoing process that creates accelerated SOUTH FORK GEOSCIENCES, PLLC Page 4 PO Box 1 275 NORTH BEND, WA 98045- 425-831-2023 1 Mione Short Plat January 11, 2017 19011 Olympic View Drive (Parcel # 00434600007800) Project #14012 Edmonds, Washington erosion and/or instability, such as stream erosion, channel migration, or toe erosion from wave action. f. Consideration of the run -out hazard of landslide debris and/or the impacts of landslide run -out on down slope properties. Res once. It is our opinion that the risk of deep-seated rotation failure of the slopes on the subject property is low and the likelihood of landslide debris run -out is low. A slope "failure" would more likely be erosion rills or minor, shallow debris flows from a very intense storm event. As such, it is our opinion that the 10-foot buffer delineated will adequately mitigate any slide debris run -out. g. A study of slope stability including an analysis of proposed cuts, fills, and other site grading; Response: Due to the buffer applied to the landslide hazard areas, the site grading will not impact the areas in question. Since the existing home will remain, the previously developed areas in or near the "landslide hazard area" and associated buffers should be maintained as they have been historically and it is our opinion that existing home and associated improvements should be considered a "non -conforming legal use" and should not be encumbered by the landslide hazard area or associated buffers. h. Recommendations for building siting limitations; and Refflonser Besides the landslide hazard areas and associated buffers, it is our opinion that no other building siting limitation are necessary. We have reviewed the referenced civil engineering plans for the proposed development and it is our opinion that the locations of proposed structures, utilities, and driveway will not create additional slope related risk. As stated in the previous response, it is our opinion that the existing home and associated improvements should not be encumbered by the landslide hazard areas or associated buffers. i. An analysis or proposed surface and subsurface drainage, and the vulnerability of the site to erosion; Res n The Vashon advance outwash sediments are conducive to stormwater infiltration. Due to their high permeability, they generate less runoff than finer grained soils and are not specifically prone to erosion. Stormwater infiltration trenches (Omega, Drainage & Grading Plan, Sheet 3) and temporary erosion and sediment control measures (Omega, SWPPP, Sheet 2) are shown in the referenced civil engineering plans. These infiltration trenches were sized based on the recommendations set forth in our referenced Soil Assessment for Design Infiltration Rate letter SOUTH FORK GEOSCIENCES, PLLC Page 5 PO Box 1 275 NORTH BEND, WA 98045 � 425-83 9 -2023 1 NDR WG. 5 GEO,.0OM Mione Short Plat January 11, 2017 19011 Olympic View Drive (Parcel # 00434600007800) Project #14012 Edmonds, Washington (SFG, April 2015). It is our opinion that these measures will perform adequately for the proposed development. 3. Geotechnical Engineering Report. The technical information for a project within a landslide hazard area shall include a geotechnical engineering report prepared by a licensed engineer that presents engineering recommendations for the following: a. Parameters for design of site improvements including appropriate foundations and retaining structures. These should include allowable load and resistance capacities for the bearing and lateral loads, installation considerations, and estimates of settlement performance; b. Recommendations for drainage and subdrainage improvements; c. Earthwork recommendations including clearing and site preparation criteria, fill placement and compaction criteria, temporary and permanent slope inclinations and protection, and temporary excavation support, if necessary; and d. Mitigation of adverse site conditions including slope stabilization measures and seismically unstable soils, if appropriate; RMonse: These design parameters and recommendations were made in the referenced geotechnical report for the project (SFG, April 2014). 4. Erosion and Sediment Control Plan. For any development proposal on a site containing an erosion hazard area, an erosion and sediments control plan shall be required. The erosion and sediment control plan shall be prepared in compliance with requirements set forth in ECDC Chapter 18.30; We have reviewed the erosion and sediment control plan prepared by Omega Engineering and it is our opinion that this plan will perform adequately during construction, if properly implemented. G. Limited Report Requirements for Stable Erosion Hazard (details omitted for brevity) Response: Not applicable. H. Seismic Hazard Areas (details and subsections omitted for brevity) Reso see" As stated in the referenced geotechnical report, there are no site specific seismic hazards (such as liquefaction potential) that significantly impact the subject property or proposed development. Recommendations for standard seismic considerations were made in the referenced report and these recommendations are still valid. SOUTH FORK GEOSCIENCES, PLLC Page 6 PO Box 1 275 NORTH BEND, WA 98045 �r 425-831-2023 1 L�.Nj, ,EE " . �?.� �mr...s.�tµ.��... M"�,.�M Mione Short Plat 19011 Olympic View Drive (Parcel # 00434600007800) Edmonds, Washington January 11, 2017 Project #14012 Closure We have enjoyed working with you on this project and are confident that the information provided in this report will aid in the design of your project. If there are any questions about this report, please feel free to contact us. Sincerely, Andrew L. Glandon, LEG, CPESC Engineering Geologist / Owner South Fork Geosciences, PLLC Attachment: Landslide Hazard Areas and Buffers References: "RE: Planning review #3 of civil improvement plans for short plat (PLN20140075)" Mike From: Clugston, Associate Planner, City of Edmonds, October 6, 2016 "Mione 2 Lot Short Plat, Sheets 1-5", Omega Engineering, Inc., Job # 14-0608, April 20,2015 "Subject: Response to Planning Department 2nd Review Comments, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington", South Fork Geosciences, PLLC, Project #14012, March 5, 2016 "Soil Assessment for Design Infiltration Rate, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington" South Fork Geosciences, Project #14012, April 19, 2015 "Subsurface Exploration, Geologic Hazards, and Preliminary Geotechnical Engineering Report, Mione Short Plat, Parcel # 00434600007800, 19011 Olympic View Drive, Edmonds, Washington" South Fork Geosciences, Project #14012, April 1, 2014 SOUTH FORK GEOSC[EN[CES, PLLC Page 7 PO Box 1 275 NORTH BEND, WA 98045 425-831-2023 1 O O 00 r- O O O O lD m O O N u L a a1 0 4- C d U to Lf C C O > v�i O —0 a� 0 0 0 0 E Lu N L r Mom I m 41 r � aw M L A fl VP A 4 la '+�� � fud e o 1yw 01 .w�Ik �'�dti �' �� �.� '� ��iG�; „� e r r J e r� " f� "' w�,Po ,� Iv�"u �' ✓ �,�. d ; " r AT—� � e CL ._s" ��Al wrri d1G N b � e _ e �kpkp .. 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