Loading...
CANOD.pdfCity of Edmonds Critical Area Notice of Decision Applicant: Property Owner: L I / Critical Area File Permit Number: F-7 Site Location:, J 3 1 1 -10 "4� Number: r "V4,15100000 1600 Project Description: 16� Ct 6? V/ (4'� e5k, E] Conditional Waiver. No critical area report is required for the project described above. 1. There will be no alteration of a,Critical Area or its required buffer, 2. The proposal is an allowed activity pursuant to ECDC 23.40,220, 23.50,220, and/or 23.80.040, 3. The proposal is exempt pursuant to ECDC 23.40.230, F—I Erosion Hazard. Project is within erosion hazard area, Applicant must prepare an erosion and sediment control plan in compliance with ECDC 18.30, ACritical Area Report Required. The proposed project is within a critical area and/or a critical area buffer and a critical area report is required, A critical area report has been submitted and evaluated for compliance with the following criteria pursuant to ECDC 23.40.160: 1 The proposal minimizes the impact on critical areas in accordance with ECDC 23.40,120, Mitigation sequencing; 2. � The proposal does not pose an unreasonable threat to the public health, safety, or welfare on or off the development proposal site; 3. The proposal is consistent with the general purposes of this title and the public interest; 4. Any alterations permitted to the critical area are mitigated in accordance with ECDC 23,40.110, Mitigation requirements. 5 The proposal protects the critical area functions and values consistent with the best available science and results in no net loss of critical functions and values; and The proposal is consistent with other applicable regulations and standards, E] Unfavorable Critical Area Decision. The proposed project is not exempt or does not adequately mitigate its impacts on critical areas and/or does not comply with the criteria in ECDC 23.40.160 and the provisions of the City of Edmonds critical area regulations, See attached findings of noncompliance. Favorable Critical Area Decision. The proposed project as described above and as shown on the attached site plan meets or is exempt from the criteria in ECDC 23.40,160, Review Criteria, and complies with the applicable provisions of the City of Edmonds critical area regulations. Any subsequent changes to the proposal shall void this decision pending re -review of the proposal. ❑ Conditions. Critical Area specific condition(s) have been applied to the permit number referenced above. See referenced permit number for specific condition(s), S � I V\ Is Reviewer Signature Date Appeals: Any decision to approve, condition, or deny a development proposal or other activity based on the requirements of critical area regulations may be appealed according to, and as part of, the appeal procedure, if any, for the permit or approval involved. Revised 12/16/2010 MUM 1/4 OF"ON Oft TOWNSHIP 27, RMCE 04 Lot Coverage Calculation TOP OF SLOPE 87'11"'35"W SF Overhang (167LF) 251 SF APF1 WVED P11 A N140",i 85,00 SF: 0 ' 38.5 /3 Deck Extension 285 $F Total 3,026 SF Percent of lot 24% —4- C) 0 CORY ANN WALKER (0 EXISTING 7315 176T1 ST SW SINGLE EDMONDS, WA 911026 FAM I LY 00456000001600 0 �-i GLEN WIN MFW TRACTS 5 61-K 000 D-00 .- LOT 16 0 29 ACRES U-1 Z- 9m RE,31DENCE F7 _Z 23.5- 2"4 b EXISTING DRIVEWAY 24' < ... .. .. ... ...... .... ...... ...... lr'uj ((') N 8-1-1135"W Civil L=siginoeringPionrgng 1724 W. Movh) Vmv D&O, Suite 140; Evaeft, washigion 98201 Olffee:425,4434AS33 Rm 42.5.486.6503 www.sdoorqyn(mxxom Existing Deck (246sf) .92 by 5.25'fei-ex or equal Proposed Deck (285sf) .92 by 5.25 Terex or equal 1 20 rm%mmPm6,j Scale WALKER RESIDENCE DECK REPAIR & REPLACEMENT PLAN Lot Coverage Calculation Flouse and Garage 2,244 SF Overhang (167LF) 251 SF Existing Deck 246 SF: 0 ' 38.5 Deck Extension 285 $F Total 3,026 SF Percent of lot 24% —4- C) 0 -4- - (0 EXISTING P10 L0 SINGLE FAM I LY RE,31DENCE F7 _Z 23.5- 2"4 b EXISTING DRIVEWAY 24' < ... .. .. ... ...... .... ...... ...... lr'uj ((') N 8-1-1135"W Civil L=siginoeringPionrgng 1724 W. Movh) Vmv D&O, Suite 140; Evaeft, washigion 98201 Olffee:425,4434AS33 Rm 42.5.486.6503 www.sdoorqyn(mxxom Existing Deck (246sf) .92 by 5.25'fei-ex or equal Proposed Deck (285sf) .92 by 5.25 Terex or equal 1 20 rm%mmPm6,j Scale WALKER RESIDENCE DECK REPAIR & REPLACEMENT PLAN LIU& ASSOCIATES, INC. Geotechnical Enginewinq Engineering Geology JUly 241, 2007 Nlh-. Cody Walker 7315 - 176"' Street SW Edmonds, INTA 98026 Dear Mr. Walker Subject: Slope Stability and Setback Evvaluation Proposed Wood Deck fixpansion WMker Residence 7315 — 176"' Street SW Edmonds, Washington L&A Job No. 13-077 INTRODUCTION Earth Scstnoe We Understand that the expansion ole an existing, Nvood deck w -rapping around the northNwst corner of the house of the subJect rQsidencc, is proposcd. The general location of the residence is shown on Plate I — Vicinity Map. The residence site Is situated on the top of as steel), northwesterly -declining hillside. T'he expanded deck 1AJll come within about 32 feet of the Top of an adjacent steel) slope of 4V or more I inclination. We understand that City of Fdmonds has concern abOUt the impact from construction of the deck on the stabiliry of this slope. At your request., we have completed a geotechnical investigation wid an cvaluation of' the stability of the slope. Presented in this report titre Our findings of the conditions of the residence site,, our evalUatiOn of stability' of the aclj , jaceill steep slope and our conclusion of the impact of the deck eow."truction to the stability of this steel) slope. OJI, 19213 nlake Place NE - Kenmore, Washington 98028 Phone (425)483-9134 - Fax(425)486-2746 JLII-v 24. 21)13 Deck Expansion — Walker Residence L&A Job No, 13-077 Page 2 Z� PROJECT DESCRIPTION The existing deck wrapping the northwest comer area of the liouse is elevated and off the main floor level, and is Supported on timber posts resting on concrete blocks, As shown on Plate 2 — Site Plan. prepared by Site Development Associates (SDA), the existing deck is 6 feet wide and is to be expanded outward 4 more feet. The expanded deck will be slap be Supported on timber posts resting on precast concrete blocks set in shallow pits. There will be minimal disturbance to existing vegetation cover directly under and in-linediately around the deck from construction of deck expansion. Tlie deck will be constructed of open timber floor planks without an impervious surface, Therefore, Construction of the expanded deck will not alter the current pattern Of Surface runoff, or increase concentrated storm ruiioff, or require special collection or disposal of storm runoff. SITE CONI)ITIONS Surface Conditions The subject residence site is Situated on the top of a steep, 1-vesterly-declinint, hillside, The terrain within the site generally slopes down northwesterly gently to about the north side of the house, then moderately steeply northward just past the north boutidarj-, of the site., then steeply northward down to a gully below. Along the north portion ol'the west boundary is a slope which drops off a few feet to the neighboring property to the west. The to -be -expanded deck will be within the moderately sloped area with a mininluin setback of 32 feet froth the top of steep slope (see attached I"late 2 — Site Plan). LIU & ASSOCIATES, INC. Jul), 24. 2013 Deck Expansion --- Walker Residence L&A Job No. 13-077 Page 3 Geologic Setting and Soil Conditions The Geologic Map of the > asters Half and Part of' the Western Half Quadrangle,;, by James P. Minard, published by U. S. Geological Survey in 1983, was referenced for the geologic and soil conditions of the lot. According to this publication-, the surficial soil units at and in the vicinity of the subject residence site are mapped as Vashon deposits (Qvt) underlain by Advance OutNvash (Qva) deposits. According to this geologic map, the Vashon till soil unit extends eastward from the top or just below the top of the hillside «,ith the advance out -NN -ash soil unit exposed on the hillside below. This advance outwash Soil unit is overlain a ag I gin b�- another Vashon till soil unit further dowtthill, roughly west of 76'h Avenue West. The advance outwash soil unit on the hillside is thus sandxviched between txvo Vashon till soil units. The geology of the Puget Sound LoNfland has been modified by the advance and retreat of several glaciers in the past and subsequent deposits and erosion. 'Hic latest glacier ,advanced to the Paget. Sound Lowland is referred to as the Vashon Shade of the Fraser Glaciation, v,,'hicli has occurred during the later stages of the Pleistocene Epoch and retreated firon-1 the region some 14,500 years ago. The deposits of the Vashon till soil unit \N�crc plowed directly, under glacial ice during the most recent glacial period as the glacier advanced over an eroded, itTe-ular surface of older formations and sediments. This soil unit is composed of a mixture of'unsorted clay, silt, sand., gravel. and scattered cobbles and boulders. The Vashon till soil over the top two to three feet is normally weathered to a medium -dense state, and is moderately LIU & ASSOCIATES, INC. July 24. 2013 Deck Expansion — Walker Residence L&A Job No. 13-077 Page 4 permeable and compressible, The Underlying fresh ti 1 11 soil. coninionly referred to as "hard pan", is very dense and weakly cemented. 'Flee fresh till soil possesses a compressive strength comparable to that oflow-grade concrete and can remain stable on steep natLiral slopes or man -make cuts for a long period. Ilie fresh till deposits are practically impervious to StorniNvater infiltration and can provide excellent foundation support with little or no settlement. The advance o-utivash soil deposits are composed of stratified sand and gravel with very minor amount of'silt and clay, deposited by the nieltw-ater of advancing glacial ice of the last glacier then overridden by the still advancing glacier-. Due to their generally granular composition, the advance outwash deposits are of moderately high pei-mcabiliq, and drains fairly well. The advance outwash deposits are generally dense to very dense in their' natural, undisturbed state. Where exposed on slopes with poor- vegetation cover and subjected to storm runoff erosion or gwUndwater seepage, the advance OUtwash soils in the top 2 to 4 feet can be gradually weathered and eroded and may sloijgh_and redeposit to a flatter inclination. Tlie underlying fresh advance outNvash deposits in their native, Undisturbed state can provide good foundation Support With little settlement expected for light to nioderately heavy structures. The Vash(-.)n till soil unit is very stable. The exposed advance OLOVaSh on the hillside sandwiched bet-wcen two VaShOn till Soil Unit :should also be quite stable. LILJ & ASSOCIATES, INC. July 214. 2013 Deck Expansion — Walltct Residence L&A Job No. 13-077 Page 5 Groundwater Conditions The very -dense, weakly -cemented, fresh till deposit underlying the top of the hillside is of extremely loNv permeability and would perch stornmater infiltrating into the more permeable surficial weathered soils. 'llie amount of and the death to the near -surface perched groundwater would fluctuate seasonally, depending on precipitation, surface runoff. ground vegetation cover. site utilization, and other factors. The perched groundwater may dry LIP completely during the diger summer and fall months and accumulate and rise in the ivet winter and early spring months, The ad-vaticc outwash deposits underlying the till soil and exposed on the hillside are of moderately high permeability and would allow stormivater to seep through easily. As a result, dMInnilatiOn and rise of near -surface perched groundwater under the subject residence site should be minimal even it) the NNct winter season, GEOLOGIC HAZARD EVALUATION Landslide Hazard The dense to very -dense, fresh. till and advance outN-vash Soils Underlying the residence site and its vicinity at shallow depth are of vej,-NI-high to high ,;hear strength and have excellent resistance against slope failures. Therefore., it is unlikely for deep-seated landslides to Occur on the site or its immediate vicinity. 1,11) & ASSOCIATES, INC. July 24 2013 Deck Expansion — Walker Residence LSA Job No. 13-077 Page 6 Erosion Hazard The weathered surficial soils mantling the steel) slope below the residence site are of low to moderate resistance against erosion, xvhilc the underlying von—dense fresh till and dense and highly -permeable advance oum,ash soils, are of hich to ni odc rate IN- h igh resistance against erosion. The weak surficial soils over the steep slope COUld be eroded if they are devoid of vegetation cover and overly saturated. The steep slope is currently dotted NNith trees -C.And covered with thick underbrush. To minimize erosion hazard, the vegetation cover on the steep slope shotild be protected and niaintained. Disposal of spoil soil and yard waste onto the steep slope should prohibited and discharge of concentrated storniwater onto the hillside should not be allo\k,ed. Seismic Hazard The Puget Sound region is classified as Scismic Zone 3 by the Uniform Building Code (UBC), The dense to very -dense fresh till and dense advance outwash soils underlying the site at shallow depth should make it rather Linlikely for scisniic hazards, such as liquefaction or lateral soil spreading, to OCCUr On the hillside, Therelore, Seismic hazards of the site should be minimal, The expanded deck will be a relative],,,, light structure and should have little impact on the stability of the adJacent steep slope. DISCUSSION AND CONCLUSION The fresh Vashon till and advance out-,vash deposits underlying the residence site at shallow depth are of very -high to high shear strength and have excellence to VerV good LIU & ASSOCIATES, INC. July 24, 2013 Deck Expansion — Walker Residence L&A Job No. 13-077 Page 7 resistance against Slope filill-lreS. Therefore, the steep slope tIqjacejjt to the deck should be quite stable. ConstrLICti011 of the deck will cause little disturbance to the site and will not create crosioii or drainage problem. Therefore., it is our opinion that the expanded deck of relatively light stwdllre, to be set back at least 32 feet from the top of the adjacent steep slope, should have little impact on the Stability of the adjacent steep slope. CLOSURE We are pleased to be of service to you. Please Feel Free to Cont"ICL LIS if VOL] have any questions regarding this report or need I'Lirther consultation. Two plates attached Yours very truly, LlU & ASSOCIATES,, TNC. J. S. (Julian) Liu, Ph.D., P.E. Consulting Gicotechnical Engirteer LIIJ & ASSOCIATES, INC. TOP OF SLOPE —N 87 " '-T,'35"W 73.93T 7-� — nn' — U-) L0 Lo -01 W -111'35"W 85.UO-'- 176TH ST SW CIVA Engineering Project Management Planning 1724 W. Maine Vkw Drive, Suite 14D; Everett, Wa*xjton 9=1 Office: 425.486.6533 Fax: 425.486.6593 w� .$doengkvemcom PROPSM QVMER CODY & ANN MIXER Existing Deck (246sf) 7315 176114 ST SW .92 by 5.25 Terex or equal EDMONDS, WA 98026 Proposed Deck (285sf) PARM NMIM 00456000=600 .92 by 5.25 Terex or equal LEML 0949flLmm GLEN MEN VIEW TRACTS WX 000 D-00 — LOT 16 Mr. M 0.20 ACRES Lot Coverage Calculation House and Garage 2,244 5F Overhang (167LF) 251 SF Existing Deck 246 SF Deck Extension 285 SF Total 3,026 SF Percent of lot 24% WMEN Existing Deck (246sf) .92 by 5.25 Terex or equal Proposed Deck (285sf) .92 by 5.25 Terex or equal WALKER RESIDENCE DECK REPMR & &EPLACEA1EWT-PUM-- NSTO "6=11111111111111 111411 r !i- �_"' -� � NEAR ALE RIO g[ p� ( I z , 1613 i I JT ih' i �' �� UW K i a C4 truci 6 17�TF- PL DT Sr1�7 ... ' �L .-.-.,—.. l2TiG° H V410 V410� �� { PROJECT � I Tt ST, EST ��t' „>s SITE— kc 1 176TH F= �( $ =17711 1 € H s L/ 7�I rni _ z �r tr u j_.t37 ..-� nr Si II: F i aI1J7H )y 173 z + €t �1e f FL k'ury/ 0 ` FLU N sd1 r'k� � 4�i+. +�:iIST � � a'rn_��`{i.- 180TH l3m ettt "'HJT �, r I lIF hI FI r F `i s 18x1 ST I3]ST Fli .5181'T t1 5is'_ iE ' r7r.7 ­­ v II.1 .,/��Z.1,+ 7EsHP. 3 Sri l;r- ! = { 17LjL 83 Sk 13 [ -t 7 -•. f in op ���� r:I ¢s( -ti _ � g�51H Sar i- _ _ iE �T11 Eai_ / �•. l ' a r P1 1"wo cr -;t.. c Tuft � lit Int fL Ssi i f _ Y -STl �} (}pT( T , xl'.z ..� 3t P"ah a`. � It1 a . k fi 1",s`�17 188I f 7 ^ 1 v�� PENNY LN PL S ?g TH PL Sly z _ - T 7£t4TH S7 5bi 90 �t�_ST Slt T . E73if Ez\ t�I `tL, 14TST FL tip; T ST-5W,�•:•ib Ptf 19rjTN PL SW r-, 19241) FL SW 192 PL r ti�2 SSf 1M 19s`FS PL F S ` y 4 `L PL I930 ST n S yN' xI r 3yTy Sd? S._� x ?_- -?3y: P •'^ aT aE ' v' } 3 t -:.,t 01f� 3 TF{ 7 +* +i f14p4 'r.F a 14I1tf ST7,�w, 9 3 PL 5N}Trl •-. Ft Sr` -cV �5 N i951''ST S� �k ' z -_� 196TH [� t. , �' T YICt QGF aNlE, ' Y JiY a q �LJ`...I971 .3T S �y ILG T� tYJJ 1> Ld"i, G �- 7Ti ST..r a ' I 198TH ST ; w,,A sl z'`'£ a Fes. 1 �i T_t 1999 IST 5 3 F4. LY,.Srei 74 SFr— -- •i `PTi3 �vF — DI 2t 1ST ST Sn _ CR , ' n —� I s 'NFT` : 23I§i ' . ST 2Q2aa ?©tt�CltSt��,= rtx - - f� t" } MINI PL 5►s ,ii ': �?2 ? t` 51 i ?rJl PAR S ST r_t74TH `20 203RD 204TI 5 s" r i L 1tt c SK a Sl ST ZQ5w Lr VICINITY MAP LIU & ASSOCIATES. INC. WALKER RESIDENCE 7315 - 176TH STREET SW Geotecflnt"l Engineering Engineering Geolo-gy , Earth Science EDMONDS, WASHINGTON