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Home My WebLink About03830 - Technical Information Report - Drainage 0 M m Nantucket Avenue Plat � 2820 Park Avenue North Renton, Washington 98056 �, UTILITY PERMIT #U15001403 '� LUA14-001272, SHPL-A � -�� DRAINAGE REPORT May 5, 2015 Updated June 3, 2015 Prepared for: Nantucket Avenue, LLC Attn: Kathieen Nash 2812 257�' Place SE � , Sammamish,Washington 98075 (206) 909-7308 � �:' � � � � � I�. Prepared by: �� ' ;� Offe Engineers, PLLC � � � Darrell Offe, P.E. . � 13932 SE 159�'' Place Renton, Washington 98058-7832 , (425) 260-3412 office � ��lo��b (425) 227-9460 fax � darrell.offe@comcast.net � 3�� 3830 Table of Contents I • Technical Information Worksheet II • Section 1: Project Overview i • Section 2: Conditions and Requirements Summary � • Section 3: Offsite Analysis ' ' i • Section 4: Flow Control and Water Quality Facility Analysis and Design � Section 5: Conveyance System Analysis and Design • Section 6: Special Reports and Studies • Section 7: Other Permits • Section 8: CSWPPP Analysis and Design • Section 9: Bond Quantities, Facility Summaries, and Declaration of Covenant • Section 10: Operations and Maintenance Manual City of Renton � TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Part 1 PROJECT OWNER AND Part 2 PROJECT LOCATION AND PROJECT ENGINEER DESCRIPTION Project Owner: Nantucket Avenue, LLC Project Name: Nantucket Avenue Piat Address: 2812 257�' Place SE Sammamish,WA 98075 Location Phone: (425) 432-5932 Township: 24 North Project Engineer: Darrell Offe, P.E. Range: 5 East Company: Offe Engineers, PLLC Section: 32 Address/Phone: 13932 SE 159th Place �� Renton, WA 98058 425 260-3412 Part 3 TYPE OF PERMIT part 4 OTHER REVIEWS AND PERMITS APPLICATION Subdivision ❑ DFW HPA n Shoreline Management �Short Subdivision ❑ COE 404 Rockery ` ❑ Grading ❑ DOE Dam Safety � StruCtural VaultS ❑ Commercial ❑ FEMA Floodplain Other NPDES _ ❑ Other Part 5 SITE COMMUNITY AND DRAINAGE BASIN Community Upper Kennydale Area, City of Renton Drainage Basin Lake Washington Part 6 SITE CHARACTERISTICS ❑ River ❑ Floodplain ❑ Seeps/Springs ' ❑ Stream I ❑ High Groundwater Table ❑ Critical Stream Reach ' ❑ Groundwater Recharge ', ❑ De ressions/Swales I P , I'� � ` Other � ❑ Lake ' ❑ Steep Slopes �� I � '� _ I Part 7 SOI LS Soil Type Slopes Erosion Potential Erosive Velocities Qva 10—25% minor ❑ Additional Sheets Attached Part 8 DEVELOPMENT LIMITATIONS REFERENCE LIMITATION/SITE CONSTRAINT � Ch. 4—Downstream Analysis ❑ ❑ ❑ � � �� Additional Sheets Attached Part 9 ESC REQU�REMENTS MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION AFTER CONSTRUCTION ❑ Sedimentation Facilities ❑ Stabilize Exposed Surface Stabilized Construction Entrance ❑ Remove and Restore Temporary ESC Facilifies Perimeter Runoff Control ❑ Clean and Remove All Silt and Debris Clearing and Grading Restrictions ❑ Ensure Operation of Permanent Facilities ❑ Cover Practices ❑ Flag Limits of SAO and open space � Construction Sequence preservation a�eas C Other � Other Part 10 SURFACE WATER SYSTEM , Infiltration Method of Analysis C Grass Lined Dispersion i Channel �� ❑ Flow Dispersal 2009 City of Renton ', X Pipe System J Energy Dissipater Drainage Manual ❑ Wetland � waiver ❑ Open Channel Compensation/Mitigati ❑ Stream � Regional on of Eliminated Site ❑ Dry Pond Detention Storage � �� L"� Brief Description of System Operation: Catch basins within private access road and along the frontage will convey stormwater runoff into a new stormwater vault located in the SW corner of the property. Vault will discharge into an existing stormwater pipe in Park Avenue North. Facility Related Site Limitations ' Reference Facility Limitation Part 11 STRUCTURAL ANALYSIS Part 12 EASEMENTS/TRACTS Drainage Easement �Cast in Place Vault � J ❑ Retaining Wall Access Easement Rockery>4' High �TraCt ❑ Structural on Steep Slope ❑ Other ❑ Other Part 13 SIGNATURE OF PROFESSIONAL ENGINEER I or a civil engineer under my supervision my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attachments. To the best of my knowledge the information provided here is accurate. nn� 2 � S� s" Zol s� igne ate Section 1: Project Overview The proposal is to create eight(8) individual single family lots and one (1) stormwater tract from this 62,520 square foot parcel located in the City of Renton, Washington. The proposal is two existing tax parcels: 2820 Park Avenue North - King County Tax parcel #334210-3281 and 2802 Park Avenue North - King County Tax parcel #334210-3282. The existing residences, impervious areas, and out buildings on the properties will be removed to create these nine new lots. The property slopes from the east towards Park Avenue North on the west. The property is located within the "Peak Rate F/ow Cont�o/Standard(Existing Site Conditions)"area of the drainage basin map. There are no sensitive areas on the project site. The property has a gentle slope of approximately 15% towards the southwest corner of the property. The soils on the site have been identified by a Geotechnical Engineers as"recessional deposits-sands and gravels"(Qvr). These soils are exceptionally well drained and will provide for suitable Full Infiltration of stormwater runoff. The soil logs indicate dry sands and gravels to depths below 8 feet on the property. The drainage calculations within this report will show that the developed runoff from this project match the existing condition runoff. A stormwater (water quality) vault has been sized to provide for water quality treatment only. The developed flows using full infiltration of impervious surfaces from the individual lots will generate less downstream runoff than the existing site conditions. A PORTION OF THE SE 1/4,SW 1/4,SECTION 32,TOWNSHIP 24 N.,RANGE 5 EAST,W.M.,CITY OF RENTON,WASHINGTON � LEGAL DESCRIPTION � �'�"°�'� 1}, NANTUCKET SHORT PLAT � a mfll M/190N NUMKR�1E98 THE �90VIH 10 fEE��T11E MCSf � f10 iEET,�ocaro�a ro n�t rur nr�,11ECOFOED IN Y7UMC 11 OP RA1S, PME 0.1,M KINO WUMY,SfATE OF NWXNqI011 R E N TO N, WAS H I N GTO N ,,.,�,,�,�,�,�� lllf NMIIUCNET 911dR PtAT 11LC Iq.LW1MOOtR7L fIMI�A O/RIIO`m IND VNICEL:3MT10-J3l1 7N�Cf/�'O(CEPf NON�R/00 FFEf ANO OfCEP�WfST 16E FEEf 1.TIE APPVCNIf 81Y11 PIq�1DE A OEfMFD WIOlCAP6 PIIN TMT 001lN8i MIM Wq 1-l-120G 5~ ��«m+a6�,,�„a,� ��,�*�;��„•�,.,,� LAND USE PERMIT# LUA14-001272, SHPL-A ;��,��„„�;;a„�,,,,,,��,,,.,�,�,,,�,,. wrrow,a� ,o su a "��°`°"�" °`""'�`"°`°��'�°�"'"".'�""a"�"'""p'°" UTILITYPERMIT#U15001403 �`�°�""""'°"TME�„��,�T.�,��.,�,�� I- a IlRKE M P�IIOIOim IG75UR11 1�11lIbnM 111E MIMIII6 SiNP ALOHO►NYf ME� [[ ��1NM 92E ll�nMT IS MVIWPNAi!/dl OINXIO/f UIOG � BASIS OF BEARING(NA083(1991) CITY OF RENTON `aC�Nm ww na is�+xn�,woan�vc rw�swi,s siamm ro n¢aw�n�r wnwno niaKer r�nna N e�are aF e�,wra von nis vnaccr x�uMc ro��rtw wa rrmovw nwn ro aonemuciwN rv�r roeuwcc i- ��vwNo e�ss asK aawN a uaHuunrt q teee uro ratve: an o �roN x.�ne sqa�w�mi v�uu ano�o M m�cr�ewu ec aesia�o ro ee�oaim uMonivaua Y VllllE4 N�ER�RE�HE1D�Fdt 7�FIESfi MM�KMIEM�8 Tp0 3!!�WN1110L� P�0'NER�: WEf 9p1H0�(PS� Q 011dNq�r rt q O�ER M�1 N M�N'ATi M�PUCA`nON q��IN �M (� NWE.Y79i11�ONIROL V/�}ILES IND A UNE BEIIKEN TMC MONUMEMS GB: PUOEf SOUID ENEROV(PSEI � YC11100 COIIID�i110►o!!D Pql NPIIOWL!Y n1E RINMq OMlOII. 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(I M[COMI�')PIII011 TO l�IId1�PU ��MN�O PPOJOCf�MID 711[CJIY ATIONEY Y•SIWL�WWI%(11ED A IMM�II PIAT IMfl10MFtlf NNJ[R 10 iNC�mPFA1MPO11i WNMm UIOOI�� IYO�-7-0lp1.2 10.lllE IP►l1fJNl!WL q01N(MIIN 111E PI�JC MOIrli 0[PMIMEIIf TO PR7A0[ILN 011 Q14VIEm SiRi110'IIfM A iEpRFlI pRLI S'1I1M10 COIDII/011 IMO O061M lOM7fA QI M lOI/IH BIOE OF MF]OfN SIRFL�(p1�1U Oii�IMP 1R�VRr�1]iMOY M�/11E �g �PIA�I1000110N0 GIY K IIO/ION dlll�101Gfpl. 11N!71/YL!E �10011 i� 1.NL 0611M�51OM A1 T6 AMI[T M[N US SIMYlT 7.UI4f1EK/�[AI0�11 1F11 fwlD O�IDMJpIS�N/W/dE IENNOi IID UIqEEA7101110 1D09[59�ACff�0[ < a+��TMS�7 TABLE OF CONTENTS ��u��M��u� �,ONTACT INFORMATION �� p�p; NMIIUCKET AVENUE,11.0 � f,pJE11 SMEET � x w,�a�me�.��r�oeu�a ao,�wo�u �rm:Pa�swu� � Urour �au�a sa�n�c muo�mc wim a no K i2oo rroRm xn�snen s auaiw/Q+oswn canaa ��.�� O� 4 [A040H CONIROL O[iNl t lqlQ OPACE PFIONF: �26-8Yl-20M p WNAIE MCCE.SS SfNEEf PIAN k PIIOF4E �I� � F7WL NaMIOMMAIamoonMtln9.� d NpRIM 2!M SIREEf PIAN k PRpIE !M C011.!OG 71 ENfiNFF.N: OFFE ENOINEERl.Pl1.0 7 PAItl(AVENUE NOrtiN PIAN t PNOFILE 0�7m MOMIIOR pI1'OI RMON ATiN:Q4tlIF1L�FFE PE E ROW/910FM DEfNl3 R NOIE3 1/11�umS PILO CONIR01.I1N IJOJ2 40UTNE/Sf 1691N PIICE G ROAD�SfORM OEfMlS k NOIES W/PIINON 7 1� 7lC.JI 10 NA7iF OWl1IY iNFA1��FNf FIql1IY OOM'tl 1.0' yp�� FIMON.MASXINQION 0l06l-70.1I (Y-10-1�) EIW!PM OONN OR' OFF7CE NUAIBER:126-2Co-7�12 I1 SEW[R PWi k PNOiR.f ��. FAK MIMBER:�25-727-YMO IT SENt11 O[TN4S/NOIE3 M JOpEf/K K ElYYLt danWl.oHNearieaN.nN IJ MAIER PUW S PROFlLE ��' _ NORTFi 28th SiREET sUR�EYat: L�NK1R[E Wq suRYEYNC.nrC. /6 uwoscliPMa vw�N01E8 �d�GYdL (9-70-I{) \ fASm MONUMflR A71H:TREVOR WMf11iEE.►l3 1! 70POf7R�PF11C lUIMY * o•� � `3Y�A6 GP M/NMdI �2J20 1111N►IACE SC p o�. ' weurtn,w��oN oeooa +� oowros�unun wN own�o.a• asice Huwem:ua-eas-eaxa +e smeer uart v�w�-+ ,�, o. �o-w-u> ow�na�e«aanaa«ana.oan ta sm�r uart ocrw�s�-2 CALL 81 1 BEFORE YOU DIG! � 3fIiLET Uplf OEfNL4 L-3 � a- • OFFE ENGINEERS • ,�„� ��. NANTUCKET SHORT PIAT Qa/�/��e tasai,ounm.�sriSvl'ttt�wcn �,y ;" �f' � RIENTON NANTUCKETAVENUE.LLC RHN'R)N,WASHIN4'IVN 99059 • �t ��;�2�1z �� COVER SHEET CONTACf:DARRBLLOPPB,P.E. � 16 � R� n, � � :.'�, 2820 PARK AVENUE NORTH ' C❑VER Section 2: Conditions and Requirements Summary I Preliminary Conditions of Plat A�proval—forth rnming ' An overview of the Core Requirements is outlined below, further discussion of these requirements can be found within the remainder of this report. Core Requirement No, 1—Discharge at Natura/Location The current property sheet flows towards the southwest comer to the intersection of Park Avenue North and North 28"' Street. The developed condition will be to discharge to stormwater facility into the existing catch basin at the southwest corner of the property. The project will connect to the existing natural discharge location. Core Requirement No, 2—Offsite Analysis The downstream system was walked (where possible) below the project in September 2014. The site drainage currently sheet flows across the property to the southwest corner. The flow is collected into a catch basin located within the northeast portion of the intersection of Park Avenue North and North 2gtn Street. The catch basin collects runoff from a portion of the existing streets together with the runoff from the project area. The catch basin flows within a 6"concrete pipe (at slope = 8.82%) across the intersection towards the southwest. The pipe discharges into a large wooded and heavily vegetated area. The end of the 6" pipe is exposed in the under story. The 6"pipe end has minor debris at the outlet. The stormwater flow from the end of the 6"pipe to the bottom of the ravine was not exposed due to the heavy overgrowth , of vegetation. The ravine flows towards the west and can be observed at two downstream road crossings; North 27th Place (bridge)and Lake Washington (culvert). The channel flow daylights into Lake Washington along the boardwalk within Gene Coulan Park. At the three downstream observation points, the channel had minor � ' water within it. The channel, at the two crossings, showed no signs of scouring or heavy erosion. The ' � bottom of the channel is difficult to observe due to the over growth. The 6"concrete pipe will be replaced as part of this permit. The City of Renton obtained permission from the Clover Creek HOA to allow for the replacement and armament of this outfall pipe. The new pipe will be a 12"N-12 pipe. Core Requirement No. 3—F/ow Control The property is located within the City of Renton, Flow Control Duration Standard, and Existing Conditions The proposal is to mitigate on all the lots using full infiltration of developed impervious surtaces by using dry wells or infiltration trenches. This will reduce the developed runoff of the overall project. A storm water wet vault will be installed at the corner of North 28th and Park Avenue (Tract A) to provide water quality treatment of the developed impervious surface runoff. The"wet vault"has been sized using the contributing area along the frontage of the project and the new private access street. The volume within the wet vault was sized at 1,888 cu feet of storage. The proposed wet vault is 2,000 cu. feet of storage. See Section 4 for calculations for the wet vault. Core Requi�ementNo. 4—Conveyance System The proposed on-site conveyance improvements will include curb, catch basins and a pipe network for collection of surFace runoff from landscape,driveways, roadways, and sidewalks. The review and analysis of this proposed conveyance system includes calculations that are provided as part of this report. The onsite (private) and frontage {Public) will be sized to convey a 25 year storm event. Core Requirement No. 5—Erosion and Sediment Contro/ A Temporary Erosion and Sediment Control Plan implementing the Best Management Practices will be included within the civil plans. The project exceeds the State requirements of clearing over 1 acre in size. Therefore the developer/contractor will need to obtain the necessary State permits. A temporary pond facility will be sized using the 2 year- 15 minute interval storm event. The calculations for the temp. pond will be included within a final report. Core Requirement No. 6—Maintenance and Operations The Maintenance and Operations for the Nantucket Plat will include both a public and private system. Within the final report will be the maintenance requirements for the facilities being installed as part of the plat and the facilities to be installed as part of the residential building permits. Core Requirement No, 7—Financia/Guarantees and Liabi/ity The Financial Guarantees and Liabilities will be required prior to the project being finalized by the City of Renton. Bond Quantity worksheets will be provided within the final report. Core Requirement No. 8— Water Qua/ity The project is required to provide water quality (WQ) treatment. The WQ has been provided within the stormwater treatment facility. Sizing for this portion of the facility is included within section 4. I Section 3: Offsite Analysis �' The downstream system was walked (where possible) below the project in September 2014. The site II drainage currently sheet flows across the property to the southwest corner. The flow is collected into a ' catch basin located within the northeast portion of the intersection of Park Avenue North and North 28th Street. The catch basin collects runoff from a portion of the existing streets together with the runoff from , the project area. The catch basin flows within a 6"concrete pipe (at slope = 8.47%) across the intersection towards the southwest. The pipe discharges into a large wooded and heavily vegetated area. The end of ' the 6" pipe is exposed in the under story. The 6"pipe end has minor debris at the outlet. The stormwater flow from the end of the 6"pipe to the bottom of the ravine was not exposed due to the heavy overgrowth of vegetation. The ravine flows towards the west and can be observed at two downstream road crossings; North 27�' Place (bridge) and Lake Washington (culvert). The channel flow daylights into Lake Washington along the boardwalk within Gene Coulan Park. At the three downstream observation points, the channel had minor water within it. The channel, at the two crossings, showed no signs of scouring or heavy erosion. The bottom of the channel is difficult to observe due to the over growth. The 6"concrete pipe will be replaced as part of this permit. 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Sq� y I • rype 2 Celehbesln-Manhda �'� 8-24 • -��` -� ,."- , 6'� ��' 8 -' Tank I / \VV`/� I � Y ��0�� :: Access Riser �tC 28•48 � �yull 4�Z "'�301 6308 \ � 5` ` '03 �5 02 '5301 ((?� veull � 49-105 _."� 4 . ,,,,, �� D Q Btoexrale - �' I�1 unknown Plpe(Public) q � .5 � � , Privately Malntalned Dlameter Prlvately Malntained `��, 12 3� �- �g9� 5�� 8 �� 511� 6 M a y 2 013 Ir Cslcbbaeln or Inlet ---� Unknown � P�^d : � �� • lype 2 Cqlehbasln-Menhole �-►� B"•24" � Tank 4 , 4 .. 5 1 . 5 i 7�,$�B` 5 1 " � ,�rq•� �' !D Acae�t Rber ��►� 25"-IB" � V�ull .-� �y.< `�., . �„ � • B � Veull � �9•� � Bioswrle 3�3,' 3 q i9 5320 �53 1 53 � � Z - 0 Unknown Disme e�Vete' � Raln Guden � ._ `� ' . � 150 30� 60� Unknown Malnts�ance Unknown Malntalnence 28 4 2 •• i.5 53 B -� 8 53 7' 8 28' 325 C;y Calahb�sin or Inbt —► �eg�a,m � �'� 8 C� Calchbaeln-Typa 2 MH �+�.►. p�.pq" P��d T m — Feet CulVelt(Public) �r 25•-�e• � PumPsuuon 5 T�4 � 5 32 5 5 4' �53 5,_I;g � g Ulemeter � qg«+ � �' � ' � � .. - �_----° llnknown Q RENTON � � . Other Conveyance �pM . 2 4201 •6 � �� •5 O5�' $2 , � 5 0 52U2 52 L -"r"' e"-2�' ComayanceT�po Jt�" � �� ton contour � � -�.—� Zs��_4e�� —�` P'�`�°��°M.'°" -- � 32 T24N R05E SW 1 /4 �4s"+ -...-. oltch Dlsciaimer. Thia inventory Information is schematic only. i It was compiled from numerous eources. It is the best information available at this time and should be used � � , :`y, '� for generei guidance only. The City of Renton is not , � responslble for errors or omissions. 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' ..� _. .Y � . 0 � � ,`� 13 6 ° aqe a , , " �Y 0,1, � . �' I ._ a '� �s :. � � \ � zt _ . ._.__..._� ',::i � , � � , \ .._.�..�.__...�_ �I , ,� , - - --�.. �1320�� " 3 8 0 1 5 � I , ' ��-- I1��,53��1 � ��so a �,00 �`, \ I o' �'p 1�66�6�02q�� \ � 4 � f::� i �I q'; ��0 4 34.q i 1 , ' 780� r�,b,i 36014 � ��„ � ,{ ,,� - _ .,_1 18, ' � � ��°e ,� ,., � � � �� .-- � , i� �.I ,,� , � , � �� ,+�1 - ��i8ed8 � �oo;� �"^- �--i-- _`,.._._.._.______—__I !��,i . � .. �i-��t , �''R , :,. � .,, ,., . ��r'r� �, � � � � �' � � � � � � � � _ 3 E� �� , � � �� '� _ , �` Section 4: Flow Control and Water Quality Facility Analysis and Design I FLOW CONTROL REVIEW Based upon the City Drainage Manual,the following steps are required to determine the mitigation of storm , water runoff of the developed project: I Full Dispersion— N/G (no good)—the property does not have 100 feet of flow path available on 'i each new lot; 'I Full Infiltration —Acceptable—the underlying sands and gravels provide excellent opportunity for full infiltration of individual lots—this will be accomplished using either dry wells or infiltration � trenches per the 2009 City of Renton Drainage Manual. � The proposal is to mitigate on all the lots using"Fu//Infi/traGon"of developed impervious sufiaces. 'I Based upon the KCRTS modeling (see detention calculations within this Section), the difference between the I'� 100-year developed runoff and the e�sting condition runoff is (0.469—0.453) 0.016 or 0.02 cfs (cubic feet ' per second). The difference is less than 0.10 cfs; therefore stormwater detention is NOT required per the Drainage Manual. , WATER UALITY REVIEW � The 2009 City of Renton Drainage Manual requires water quality treatment for projects that add 5,000 �� square feet or more of"new" pollution generating imperious surfaces (PGIS). The proposed developed I (PGIS) exceed this requirement and therefore water quality (WQ) treatment has been sized within a wet '� vault. The WQ portion of the vault will be sized to provide the required volume of 2,000 cubic feet (see Water Quality calculations within this Section). A'�wet vaulY' has been sized to 10'x 40'x 8'deep to be placed within Tract A. Tract A will be owned and the landscaping maintained in Common amongst the lot ' owners; the stormwater system within Tract A will be maintained by the City of Renton. ,i 'I I '_ . N Z O � g � U J Q U � Z O � H g � V J V Z O � F- z W 1� W � 2820 Pa�kAvenue North P/at Ar�ea Breakdown Existing Condition Area Impervious Pervious Ar�ea Br�eakdown , feet , feet . feoet 2820 Park A venue North 42420 House w/overhang 1390 I Oriveway (PGIS) 3145 Ex. Garage 435 Green House 95 Shed 929 Wa/kways 794 Lawn 35632 ' 6788 35632 2802 ParkAvenue North 20100 II House w/overhang 990 Driveway(PGIS) 545 Concrete Patio w/fire p/ace 1093 Stairs/Wa/kways 41 Lawn//andscaping 17431 Z669 17431 Frontage 13800 Existing asphalt 4692 Existing/andscape 9108 4692 9108 Tota/Area 76320 1.75 acres Tota/Impervivus Area 14149 0,32 acres Tota/Pervious Area 62171 1,43 acres 2820 Pa�k A venue North P/at 4/22/2015 Area Breakdown Deve%ped Condition area rmpervious Pervious Area Breakdown (sq. feetJ , feet , feet 29'Access Easement 9573 6,968 2605 TractA 3513 - shared driveway 552 - landscaping 2961 ;,,�� , 4�; �F ��w. �.,: �-�� ', Lots(w/o access easement) 46348 !(� ��;; Lots 1 - 8 (C o�° . : - 'h �T� A.�� , . , ., ;, , .. -4,000 sq. feet per lot 32000 32000 ((Full Mitigated)) Lot landscaping 14348 frontage Improvements 16886 - roadway 6842 - sidewalk 2500 -landscape area 7544 Tota/Area 76310 1.75 acres � ' 31-� Tota/Impervious Ar�ea 16862 "� ^ 0.38 acres Tota/Pervious Ariea 59458 , -,, 1.37 acres � .�1 �, . ,�,�>> �hd� , `�l toVPreµ�~� — : � •�`��_ ,I !� ,",_cl . - � NANTUCKET— EXISTING CONDITIONS - � �� - F�;. � � �� Area---- -- ?� Tiil Forest 0.00 acres Till Pasture 0.00 ac�es Till Grass 1.43 acres Outwash Forest O.UD acres Ouiwash Pasture O.DO acres Outwash Grass 0.00 acres Wetland 0.00 acres Impervious 0.32 acres _ ---___ - .. -Totai - _ ___ 1.75 acres� ______..__ _ Scale Factor: 1.00 Hourly Reduced Time Series: Nantucket Existing Condition » Compute Time Series � , Modify User Input � ----. _- -- _�__--_ _ _.___ -- --------- -------__ _._..-------- File#or computed Time Series [.TSF] _ _ __ _ ,. __ _ _ �. :.. �{�� Flow Frequency Analysis -------------------------------------------------------- Time Series File:nantucket existing condition.tsf Project Location:Sea-Tac ---Annual Peak Flo� Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period , 0 .205 4 2i09i01 2:00 0.453 1 100.00 0.990 0. 134 7 1i05i02 16:00 0.254 2 25.00 0.960 � � s�,� 0.254 2 2i27�03 7:00 0.214 3 10.00 0.900 �ir� 0. 107 8 8i26iO4 2:U0 0.205 4 5.00 0.800 0 .137 6 10i28iO4 16:00 0.197 S 3.00 0.667 0 .214 3 1i18i06 16:00 0.137 6 2.00 0.500 0.19? 5 11i24i06 3:00 0.134 7 1.30 0.231 0.453 1 1i09i08 6:00 0. 107 8 1.10 0.091 Computed Peaks 0. 387 50.00 0. 980 . '� � � / NANTUCKET- DEVELOPED CONDITION I 1 , �„�� Area --- ?} , Till Forest 0.00 acres Ti11 Pasture O.QO acres'. Till Grass 1.37 acres' Ouiwash Forest 0.00 acres; Outwash Pasture 0.00 acres' I Ouiwash Grass 0.00 acres'' Wetland 0.00 acres I , Impervious 0.38 acres _ _ _ _ ____ __ ,I Total ____ _. 1.75 acres I� _ -__------- Scale Factor : 1.00 Hourty Reduced Time Series: Nantucket Developed Condition » Compute Time Series 1 Modify User Input � ___.._._____—___ _______----.--_._.._______..________.___--__ _.--__-------.--. -- . -.__— , File for computed Time Series [.TSF] �'�, i _ _._ _ _ . _ _ '� .:J�� .. ,. _ ... _ .��.....,_�::: . � ; _�� Flow Frequency Analysis - -------------------------------------------------------- _,� Time Series File:nantucket developed condition.tsf Project Location:Sea-Tac ---Annuai Peak Flow Rates--- -----Flo�a Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) {CFS) Period �� 0.214 4 2/09i01 2:00 0. 469 1 100.00 0. 990 0.144 7 1i05i02 16:00 0. 265 2 25.00 0.960 -"� 0. 265 2 2i27iO3 7:00 0. 224 3 10.00 0.900 ` ��'� ; 1 0.12D 8 8i26iO4 2:00 0.219 4 5.00 0.800 0.153 6 10i28iO4 16:00 0.207 5 3.00 0.667 0.229 3 1i18i06 15:00 0.153 6 2.00 0.500 0.207 5 11i24i06 3:00 0.144 7 1.30 0.231 0.459 1 1i09i08 6:00 0.120 8 1.10 0.091 Computed Peaks 0.401 50.00 0.980 . �1 � � / ikF"` . , �. ,.,..,� .....�, .,, �„.. � �, ��'' T;;:.: 1 - ' � ,..�� w ,� �p� . . � � .w � �� u `�i�/ � I ° . ;' � � lrw� . � * R , � w ��t' s'' ,��""` � � � ■ ` � ..��:.,�: w r � "' r, �F � � � :� �t �. � � � . �� , .:��P� � a�� `� °y � i', Y..".T � !� � � a� `� ig �.. �� « �� . � �. ,'sW"0'�� '°S:w �.�w� '�,:X`M �+ . i � � �t � '��q �' '"� � �.'e'''�J i ��'�'� °5 � ':� ��{IiII , x�. �# i�,r� tiF ''�''`. 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I .. �kr .Y__:MJ .._ .fi.... t � ... i. � � --(� ...,.�.. �, , ey u �"-�� , � a-�te",,�,.'� w„ J�. . ¢ � .. jt* .-.....I � I � ��fi,�" ... _ .:�,'.. � ... � ,.. �. -�� _ . ,� � -., ��: �� - �. ��.. , ; - � �,�. .��. .� ��,..:... ��r �a..iu--iq � �-��"�� azv�i�ii. � �Mxoaa �IW31']'V4CC .. . . .. � i Wetpool Sizing Calculations Per 2009 King County Stormwater Management Manual Project Name: 2820 Park Avenue North Plat - Project Number: Frontage &Access road treatment Facility Description: Water Quality Sizing ((04/22/2015)) Step 1: Identify required wetpool volume factor(f). f= 3 Per KCSWDM 6.4.1.1 Step 2: Determine rainfall (R)for the mean annual storm. R= 0.47 Per KCSWDM Fig. 6.4.1.A Step 3: Calculate runoff from the mean annual storm (V�)for the developed site. V�_ (0.9A; + 0.25Ary+ 0.10A�+ 0.01Ao)x(R/ 12) where: A; = Impervious Surface Area= 16,676 s.f. At9=Till Grass Area = 4,244 s.f. Aff =Till Forest Area = 0 s.f. Ao = Outwash Area = 0 s.f. v,= 629 c.f. Step 4: Calculate required wetpool volume (Vb). Vb= fxV� Vb= 1,888 c.f. j ACCE55 COVEft OR DOORS REAISSRED. � � . . . . . . . . . . �m L.ADOE� A � • !1 ♦ o � . - 5'X 10'GRATc OV ER SEi.^OND CELI � . (tJAY BE PROVi�9V A 6RATED � WIDTN . S X 70'A�ESS DODR OR PANEL) A � �Q � . 'V'SHAAED �� T R---�- . . BOTfO1N REMWABL� BAFRE OR WALL SEE hOTE ' . ' . _ _ _ �JUT� � WETPOO�LEN:�T}.,/�Q � � � OPEN PIPE FOR WETVAULT pNLY � —t � SEE DETfTE�1TION VAULT FOR I pLqM y�Eyy COfA61NED WATER QUALfTY/ . FRMiE,GRlTE AI�� N.� I DETEMTION VAULT OUP ET � LOCKING CXNER MARKED '. B ! 'DRAIN'{IYP.) � ' _ ' ' ' ' ' ' ' ' ' _ ' _ ' _ SIZE TO NEET CAhNEYANCE DETENT70N0?'TI�ONA� REWIREMENTS(CH,7) � �l.n •7C t.ADOEa l ! !iv �6J 1� �� WQ OESIGN WS _T—_-�__�� INEIT REMOVABLE �� BAffIE � NOTE: CiiPAGN OF OUTLET FIRST ct1L sizEo�t �� W�� PIPE DESIGNED TO PEAFC ROVSI 2596 TO 35%OF w�aoo!vOul►¢ DEPTt4 1'FOR WQ VALATS Z FOft COM/EYAtJCE ( ►/ 8 MAX PDR Cq1&NED WQ 4��i F S 3'MIN. `Q'I AND�ETEt3F10N VAI.�TS — �2'min. '' � � GRAVITY DRAIN{IF GRADE AtlOVfS)PLACF I . AS LOW AS GRA�E ALLOWS BUi MIST I - _ - ' • BE fi MIN.ABOVE THE BASE ELEYA710N '� - - - � - CF VAULT WALLS�t ABOVE SE��M , BOTTOM SLflPE 0.5342R6 � ' ' STORAGE AitEA � TOLYARC INLET END A�RAGE SFDIMEM STORAGE �� SECTION A-A 1'M�L(FlRS7 C0.L] MTS \—BO170?I SLOPE SS276 TOmIARIIS WRET ENO OF SECONG CEiL(RE:AM�7ENDED) f— ACCESS DDORS OR RF3ADVA8lE PANEl / . �/��j��j��j��/��J . � \��\��\\��\\��\\��\. WO OESIGN WS _ _ L 'i�j\�j\�j\�/��/ = ��`\/ T MIN. j +1�N1! � — AVFRa6ETSEpMEARSTORAGE � � (FIRST CEL1) 1 — — —_. — T AVERAGEt'SEDIh�!JTSTORAGE % (FIRSTCELL) � SECTiON B-B NOT£: NTS 1.1. THE 4AULT SHALL BE SEPARATED JIdrO TWO GELLS ITY A WALL�A REMOVASLE BAFFtE.IF A WALI OR NON RE640VA8LE BAFFLE IS USED,A rF00T C X 10-FOOT REMOVABLE REMOVAB�E NWNTENANGE ACCESS MOST 8E PROVIDEO FOR 80TH CELLS. 1.2 FOR VAULTS UNDER ROADWAYS,THE REMOVABI.E PRNA MUST BE LOCATED DUTSIDE THE TR,4VEL LANES. A�TERNATiUELY.MULTIPLE STANDARD LOCKING�,AANHOLE COVERS MAY BE PROVIDED.SPACMG OF MANHpLE COVERS SHALL BE�2 FE�i,MEASURED ON CENTER,TO FACiLITATE REM�VAL OF SEDIMENT.LADDERS AND HAND-HOL�S NEED ONLY BE PROVIDED AT 7HE OtIiIET PiPE AA�tNLET PIPE, ti�Y a S'i'D. PI.AN - 248.20 ��* ?liBLIC j1`ORKS WETVAULT `f'FNd DEP�IRT�4ENT t3�RCH 2O0B Section 5: Conveyance System Analysis and Design I ;- Final conveyance calculations will be provided after an initial re�iew of the civil plans has been received from the City of Renton. +'� � _. J `y. A � .� / ....,' __' '_'-_._... �," _._- _' : � ` �'f'^'--�\,�_.�. _r-'�'-- ---�''"-�-�--�-•r'-- - if=-'�' �`"---y-.� r« '�� \`� �� \ �~--— _� M��■ �'7�� 4.4t1a%O.ZN tA �i�st�rmur . " -„ �_ y _>`...— _ �kecw•i ��■ 1� a�p i.e' ar cwncn g y �r �.A�� \ ::�l��` �� . �� - ` ��■ � .. I / � �:�; ,,r-. - �-� � , =r . , =;! 1 -- �- - -- —... _ ,f � � � / i�' . ._ , __ {� �� / i ' I / - ■ /,, �:° ,y' +r ..r .r r•' O �".—r . 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NU M101 '.{W61 M4 °•� 4.A (0.-10�1�1 'nM.a�' i w•,"f'. oa��zr.r n „}�� STORMWA TER CONVEYANCE BACKWA TER CALCULA TION SHEET (1) (2) (3) (4) (5) (6) (7) (8) (9) (10) (11) (12) (13) Barrel Entrance Entrance Pipe MaxF/o Pipe Outlet Inlet Barrel Barrei Velocity TW Friction HGL Head Segment Q Length Pipe "n" Elev Elev Area Velocity Head Elev Loss Elev Loss CB to CB cfs ft Size Value feet feet s . feet f s feet feet feet feet feet pipe end-CB#1 0.43 53 6" 0.012 193.22 197.88 0.1963 2.19 0.07 193.22 0.005 193.23 0.00 #CB i - #C62 0.43 44 12" 0.011 197.88 198.32 0.7854 0.55 0.01 198.13 0.0001 198.13 0.00 (14) (15) (16) (17) (18) (19) (20) (21) Exit Outlet Inlet Approach Bend Junction Head Control Control Velocity Head Head HW RIM ELEV Loss Elev Elev Head Loss Loss Elev UPSTREAM feet feet feet feet feet feet feet CB 0.07 193.30 198.20 0.07 0 0 198.13 201.50 OK.� 0.01 198.14 198.32 0.01 0 0 198.31 203.10 OK.� **Peak Flow - this is the "peak flow rate" being discharged from the storm water vault during A 100 year storm event Flow rate can be found within the KCRTS routing calculations, Section 4 4.2.1 PIPE SYSTEMS—METHODS OF ANALYSIS li FIGURE 4.21.I BACKWATER CAL ATION SHEET N CUL OTES Column(1) - Design flow to be conveyed by pipe segmerrt. Column(2) - Length of pipe segment. , Column(3) - Pipe Size;indicate pipe diameter or span x rise. Column(4) - Mannings"n"value. Column(5) - Outlet Elevation ofpipe segnent Col�unn(6) - Inlei Elevation of pipe segnent Column(� - Barrel Area;this is the fiill cross-sectional area of the pipe. I Column(8) - Barrel Velocity;this is the full velocity in the pipe as determined by: � V= Q/A or CoL(8) = Col.(1)/CoL('n Column(9) - Bartel Velociry Head = i�/2g or (CoL(8))'/2g I where g=32.2 ft/sec' (acceleration due to gravity) I Column(10) - Tailwater(7'ff�Elevation;this is the water surface elevation at the outlet of the pipe segment. If the pipe's outlet is not submerged by the TW and the TR'depth is less U�an(D+d�y2,set TW equal to(D+d.}/2 to keep the analysis simple and still obtain reasonable results (D=pipe barrel height and d�=critical depth,both in feet. See Figure 43.1.F(p.4-49)for determination of a�). Colimui(11) - Friction Loss = Sfx L [or Sfx Col.(2)] where Sfis the fiiction slope or head loss per linear foot of pipe as determined by Mannings equation expressed in the form: Sf= (n[7'/2.22 R" Column(12) - Hydraulic Grade Line(HGL)Elevation just inside the entrance of the pipe barrel;this is detertnined by adding the friction loss to the TW elevation: Col.(12) =CoL(11)+CoL(10) If this elevation fails below the pipe's inlet cmwq it no longer represents the true HGL when computed in this maru�er. The true HGL will fall somewhere between the pipe's crown and either normal flow depth or critical flow depth,whichever is greater. To keep the analysis simple and still obtain reasonable results(i.e.,erring on the conservative side),set the HGL elevation equal to I the crown elevation. I Column(l3) - Entrance Head Loss = K x IjRg [or 14 x CoL(9)] where K�= Entrance Loss Coefficient(from Table 43.1.B,p.4-42). This is the head lost due to flow co�rtractions ai the pipe entrance. Column(14) - Exit Head Loss = 1.0 x i�/2g or 1.0 x CoL(9) This is the velocity head lost or transferred downstream. Column(15) - OutletControlElevation = Cal(12)+Cd.(13)+Col.(14) 'Iliis is the maximum headwater elevation assuming the pipe's barrel and inledoudet characteristics are co�olling capacity. It does not include structure losses or approach velocity considerations. Column(16) - Inlet Control Elevation(see Secdon 43J.2,page 4-39,for computation of inlet control on culverts);this is the maximum headwater elevarion assuming the pipe's inlet is controlling capacity. It dces not include slructure losses or approach velocity considerations. Column(17) - Approach Velocity Head;this is the amount of head/energy being supplied by the discharge from an upstream pipe or channel section, which serves to reduce the headwater elevation. If the discharge is from a pipe,the approach velocity head is equal to the barrel velocity head computed for the upstream pipe. If ihe upstream pipe ouHet is significanUy higher in elevation(as in a drop manhole)or lower in elevation such that its discharge er►ergy would be dissipated,an approach velocity head of uro should be assumed. Column(I8) - Bend Head Loss = Kb x V/2g (or Kb x Col.(17)] where Kb = Bend Loss Ccefficient(&om Figure 4.2.1.K,p.4-27). This is the loss of head/energy required to change direction of flow in an access struchue. Column(19) - l�mcrion Head Loss. "fhis is the loss in head/energy that resulu from the turbulence creatad when two or more streams are merged into one within the access struchue. Figure 4.2.1.L(p.428)may be used to determine this loss,or it may be computed using the following equations derived from Figure 42.1.L: Junction Head Loss = K;x VC2g [or K,x CoL(17)] where K;is the Junction Loss Ccefficiem determined by: K� _ (Qs�Qi��1.18+0.63(Q�Q�)) Col�n(20) - Headwater(HW)Elevation;this is determined by combining the energy heads in Columns 17,18,and 19 with the higi�est contro] elevation in either Column 15 or 16,as follows: Col_(20) = Col.(ISor]6)-Col.(17)+Co1.(1g)+Col.(19) 2009 Surface Water Design Manual 1/9/2009 4-25 SECTION 4.2 PIPES,OUTFALLS,AND PLJMPS � 1.49 zr� vz (4-1) Y = R S n or use the continuity equation,Q=AV,such that: 1.49 2�3 �,n (4-2) Q = AR S n �I where Q = discharge(cfs) � V = velocity(fps) A = area(s fl n = Manning's roughness coefficient; see Table 42.1.D below R = hydraulic radius=area/wetted perimeter(ft) S = slope of the energy grade line(ft/ft) For pipes flowing partially full,the actual velocity may be estimated from the hydraulic properties shown in Figure 4.2.1.G by calculating Qf,��and V�,�l and using the ratio Q�S;g„/Q�11 to find V and d(depth of flow). Table 4.2.1.D provides the recommended Manning's"n"values for preliminary design using the Uniform Flow Analysis method for pipe systems. Note: The "n"values for this method are 1 S%higher in order to account for entrance, exit,junction, and bend head losses. ' TABLE 4.21.D MAN1vING'S "n" VALUES FOR PIPES � ,. Type of Pipe Material Analysis Method Uniform Flow Backwater Flow (Preliminary (Capacity design) Verification) A. Concrete pipe and LCPE pipe 0.014 0.012 B. Annular Corrugated Metal Pipe or Pipe Arch: 1. 2-2/3'x'/2'corrugation (riveted): a. plain or fully coated 0.028 0.024 b. paved invert(40%of circumference paved): 1) flow at full depth 0.021 0.018 2) flow at 80%full depth 0.018 0.016 3) flow at 60%full depth 0.015 0.013 c. treatment 5 0.015 0.013 2. 3"x 1"corrugation 0.031 0.027 3. 6"x 2" corrugation (field bolted) 0.035 0.030 C. Helical 2�/3'x'/Z'corrugation and CPE pipe 0.028 0.024 D. Spiral rib metal pipe and PVC pipe 0.013 0.011 E. Ductile iron pipe cement lined 0.014 0.012 F. SWPE pipe (butt fused only) 0.009 0.009 - �2 � ' N � � P 1/9/2009 2009 Surface Water Design Manual 4-20 43.1 CULVERTS—METHODSOFANALYSIS 4.3.1.2 METHODS OF ANALYSIS This secrion presents the methods of analysis for designing new or evaluating existing culverts for compliance with the conveyance capacity requirements set forth in Section 1.2.4, "Core Requirement#4: Conveyance System." ❑ DESIGN FLOWS Design flows for sizing or assessing the capacity of culverts shall be detemvned using the hydrologic analysis methods described in Chapter 3. ❑ CONVEYANCE CAPACITY The theoretical analysis of culvert capacity can be extremely complex because of the wide range of possible flow conditions that can occur due to various combinations of inlet and outlet submergence and flow regime within the culvert barrel. An exact analysis usually involves detailed backwater calculations, energy and momentum balance,and application of the results of hydraulic model studies. However,simple procedures have been developed where the various flow condirions are classified and analyzed on the basis of a control section. A control section is a location where there is a unique relationship between the flow rate and the upstream water surface elevation. Many different flow conditions exist over time,but at any given time the flow is either govemed by the culvert's inlet geometry (inlet contron or by a combination of inlet geometry,bairel characteristics,and tailwater elevation(outlet contron. Figure 43.1.A(p.4-44)illustrates typical conditions of inlet and outlet control. The procedures presented in this section provide for the analysis of both inlet and outlet control conditions to determine which governs. Inlet Control Analysis Nomographs such as those provided in Figure 4.3.1.B(p.4-45)and Figure 43.1.0(p.4-46)may be used to determine the inlet control headwater depth at design flow for various types of culverts and inlet configurations. These nomographs were originally developed by the Bureau of Public Roads—now the Federal Highway Administration(FHVJA�—based on their studies of culveR hydraulics. These and other nomogaphs can be found in the FHWA publication Hydraulic Design of Highway Culverts, HDS No. #5 (Report No. FHWA-IP-8S-1 S), September 1985;or the WSDOT Hydraulic Manual. Also available in the FHWA publication,are the design equations used to develop the inlet control nomographs. These equations aze presented below. For unsubmerged inlet conditions(defined by Q/AD°S<3.5); Form 1*: HW/D = H�ID+K(Q/AD0�5)`N-O.SS** ., (4-3) II �,�� ' _ �..ti��5� �� (�� ' / �. Form 2*: HW/D = K(Q/AD°5� (4-4) l/ For sabmerged inlet conditions(defined by Q/AD°�5>4.0); i � �� HW/D =c(Q/ADo.s�z+Y-O.SS** - (4-5) ` � i/' —�� I- l/a- where HW = headwater depth above inlet invert(ft} � � � �C�-�� Q. jR63�(�-�� t j(�„J.� D = interior height of culvert barrel(ft) ��" H� = specific head(ft)at critical depth(dc+ Yc2/2g) Q = flow(cfs) t l� Q_S� �, '� A = full cross-sectional area of culvert bazrel(s� �t 2009 Surfaoe Water Design Manual 1/9/2009 439 G"� ��/ {�G+��O �� G .�'��I��F3� � ��7 -D �� /�. 0�79 � � r_�>�u SECTION 4.3 CULVERTS AND BRIDGES � S = culvert barrel slope(ft/ft) I�M,c,Y = constants from Table 43.1.A. The specified head H�is determined by the following equation: H� = d�+V��l2g (4-6) where d� = critical depth(ft);see Figure 43.1.F(p.4-49) Y� = flow velocity at crirical depth(fps) g = acceleration due to gravity(32.2 ft/sec2). * The appropriate equation form for various inlet types is specified in Table 4.3.1.A(p.4-40 **For mitered inlets,use+0.75 instead of-O.SS. Note:Between the unsubmerged and submerged conditioru, there is a transition zone(3.5< Q/AD°5< 4.0)for which there is only limited hydraulic study information. The transition zone is defined empirically by drawing a curve between and tangent to the curves d�ned by the unsubmerged and submerged equations. In most cases, the transition zone is short and the curve is easily constructed. TABLE 4.31.A CONSTANTS FOR INLET CONTROL EQUATIONS* Unsubmerged Submerged Shape and Material Inlet Edge Description Equation Form R M c Y Circular Concrete Square edge with headwall 1 0.0098 2.0 0.0398 0.67 Groove end with headwall 0.0078 2.0 0.0292 0.74 Groove end projeeting 0.0045 2.0 0.0317 0.69 Circular CMP Headwall 1 0.0078 2.0 0.0379 0.69 Mitered to slope 0.0210 1.33 0.0463 0.75 Projeding 0.0340 1.50 0.0553 0.54 Redangular Box 30°to 75°wingwall flares 1 0.026 1.0 0.0385 0.81 90°and 15°wingwall flares 0.061 0.75 0.0400 0.80 0°wingwall flares 0.061 0.75 0.0423 0.82 CM Boxes 90°headwall 1 0.0083 2.0 0.0379 0.69 Thidc wall projecting 0.0145 1.75 0.0419 0.64 Thin wall projecting 0.0340 1.5 0.0496 0.57 Arch CMP 90°headwall 1 0.0083 2.0 0.0496 0_57 Mitered to slope 0.0300 1.0 0.0463 0.75 Projeding 0.0340 1.5 0.0496 0.53 Bottomless Arch 90°headwall 1 O.Od83 2.0 0.0379 0.69 CMP Mitered to slope 0.0300 2.0 0.0463 0.75 Thin wall projecting 0.0340 1.5 0.0496 0.57 Circular with Smooth tapered inlet throat 2 0.534 0.333 0.0196 0.89 ' Tapered Inlet Rough tapered inlet throat 0.519 0.64 0.0289 0.90 *Source: FHWA HDS No. 5 1/9/2009 2009 Surface Water Design Manaal 4-40 SECTION 4.3 CULVERTS AND BRIDGES TABLE 4.3.1.B ENTRANCE LOSS COEF`FTCIENTS Type of Structure and Design Entrance Coefficient,g� Pipe. Concrete. PVC. Sqiral Rib, DI,and LCPE Projecting from fill,sodcet(bell)end 0.2 Projecting from fill,square cut end 0.5 Headwall, or headwall and wingwalls Socket end of pipe(groove-end) 0.2 Square-edge 0.5 Rounded(radius= '/,ZD) 0.2 Mitered to cor�form to fill slope 0.7 End section oonforming to fill slope* 0.5 Beveled edges, 33.7°or 45°bevels 0.2 Side-or slope-tapered inlet 0.2 Pipe, or Pioe-Arch. Corruaated Metal and Other Non-Concrete or D.I. Projeding from fill(no headwall) 0.9 Headwall, or headwall and wingwalls(square-edge) 0.5 Mitered to conform to fill slope(paved or unpaved slope) 0.7 End secbion confortning to fill slope` 0.5 Beveled edges, 33.7°or 45°bevels 0.2 Side-or slope-tapered inlet 0.2 Box. Reinforced Concrete Headwall parallel to embankment(no wingwalls) Square-edged on 3 edges 0.5 Rounded on 3 edges to radius of'/12 barrel dimension or be�eled 0.2 edges on 3 sides Wingwalls at 30°to 75°to barrel Square-edged at crown 0.4 Crown edge rounded to radius of'/�Z barrel dimension or beveled top 0.2 edge Wingwall at 10°to 25°to barrel Square-edged at crown 0.5 Wingwalls parallel(extension of sides) Square-edged at crown 0.7 Side-or slope-tapered inlet 0.2 " Note: "End section conforming to fi/!s/ope'are the sections commonly avai/able from manufacturers. Fr�om fimited hydraulic tests fhey are equiva/ent in operation to a headwall in both inlet and oudet control Some end sections incorporating a closed taper in their design have a superior hydraulic performance. 1/9/2009 2009 Surface Water Design Manual ' 442 � SECTION 4.2 PIPES,OUTFALLS,AND PUMPS FIGURE 4.21.F NOMOGRAPA FOR SIZING CIRCULAR DRAINS FLOWING FULL 1,000 900 800 .0001 700 2.0 600 ��2 500 Minimum .0003 Allowable 400 .0004 .0001 .0005 Velocity 300 .0006 (Flowing 3.0 .0008 .0002 Fullj �20 N .001 108 4 .0003 200 g� � .0004 84 � .002 .0006 4.0 72 O .003 .0008 .004 � o � .001 Q 5.0 100 90 54 c�i� .008 .002 o O 80 48 .01 o / v 6.0 70 W .003 � uWi 60 v 42 .004�� w 7.0 � .02 .005 O 36 � � 50 z 33 .03 .008 a w p I Z 40 W � •� .010 � w , w a 27 _� cn Z 9.0 , � 30 � 24 .08 .020 10.0 = O 21 .10 � � � .030 v 0 2p � 18 .p4p � I ¢ 15 � > p .080 �.d-�� i 12 .100 ; 10 �� I' 9 S PLE USE 8 7 $ 24"dia.CMP @ 2%siope yields 20.0 6 17cfs @ 5.4 fps velocity 5 6 (n=0.024) 4 Values per Manning's equation Q=( 1.49 � ARZIs go/z 3 n 30.0 This table can be converted to other"n"values by applying 2 � formula: 40.0 Q� � Q1 _ n2 � � n1 , � l,�"�` �� _ a ��-- � �.�� _ �,� c� � 2 �� , ,� C.Q r.,e►�+�. �� g� �cI 1/9'2009 2009 Surface Water Design Manual�f� 4-22 [ Section 6: Special Reports and Studies Geotechnical Study attached Preliminary Short Plat Conditions of Approval - attached � O a W � J � H Z 2 U W E- � W � ,, Robert M. Pride, LLC Consulting Engineer !_ November �, 2oi4 Mr. Darrell Offe Offe Engineers 13932 SE i59�Place Renton, WA 98058 Re: Geotechnical Recommendations ' Proposed Residential Development �� 280o Park Avenue North �� Renton, Washington I Dear Mr. Offe, This report provides recommendations for onsite storm water infiltration on this proposed nine lot subdivision located on the northeast corner of Park Avenue and North 2gtn Street in Renton. It is understood that a detention tank is also being proposed for contaminated water storage on the west side of the project site. Site and Subsurface Conditions This rectangular property covers nearly two acres of land that has a gentle slope from the east to west side. An existing residence is situated on this property near the south end that will be removed as part of this new development. A new roadway will e�ctend toward the north end of this development to provide access to these new residences. Geologic research of mapping by Booth in 200�shows this area of Renton is underlain by recessional deposits consisting of silty sands, sands and gravels (Qvr). Field exploration consisted of excavating four exploratory test pits and documenting subsoil conditions in an open excavation located south of Lot #i. Summary logs of these test pits are described below and their locations are shov�Tn on Drawing No. 1: TP-1 Located on Lot 2 at the west end o.o to i.oft Topsoil — Silty Sand; dark brown, moist, loose; i.o to 3.5ft Silty Sand;light brown, moist, medium dense; 3•5 to 8.oft Sand with gravel; light brown, moist, medium dense; no groundwater encountered; TP-2 Located at south end of Lot 3 o.o to 1.3ft Topsoil — Silty Sand; dark bro�-n, moist, loose; 1.3 to5.oft Sandy Gravel;light brown, moist, medium dense to dense; no groundwater encountered; TP-3 Located on Lot 2 at the east end o.o to o.9ft Topsoil — Silty Sand; dark brown, moist, loose; 0.9 to 3.oft Silty Sand;light brown, moist, medium dense; 3.o to 7.5ft Sandy Gravel; light brown, moist, dense; no seepage; Robert M. Pride, LLC Page 1 13203 Holmes Point Drive NE Kirkland,WA 98034 TP-4 Located on property south of Lot � as an open excavation o.o to i.oft Topsoil— Silty Sand; dark brown, moist, loose; �.o to 4.oft Gravelly Sand;light brown, moist, medium dense; 4.o to 9.oft Sand;light brown, moist, medium dense; no groundwater seepage encountered; Based on my site investigation and geologic research the native soils below the topsoil layer consist of silty sands, sands and sandy gravels that will perform adequately for storm water discharge into these granular sediments. I have classified these upper soils as "medium sand" and the lower sandy gravels as "coarse sands or cobbles" in accordance with the King County Design Manual —Table 4.5.2. Maximum infiltration rates range from 7.5 min/inch for the fine sands, and 3 min/inch for the coarse sandy gravels. Please call if there are any questions. Respectfi�lly, �-g� 11�, l��' �,p��Q6 W A Sy��,�'� V �4 � � �O � �� ., y � - � � / �0 �6 �� d �, ��.�n 'Q'FG t S T E�E,9 \�,<v �SS10NAL ��G Robert M. Pride, P. E. Principal Geotechnical Engineer dist: (1) Addressee encl: Drawing No. 1 — Site Plan Tmp: Offe28thResidi Robert M. Pride, LLC Page Z II 13203 Holmes Point Drive NE Kirkland, WA 98034 � � { �, ------- ; ssMr+. sa� s�u�osa 'yY'' � RIM=212.00 �� .-.- __ _,._._.._.._:_.1 tE=207.00, 8' , � -- - . � .. ...-� ...- :' _.---� - � - ��.- . - --- �-- -- -_.. ___. _.. USE EXr StDE_ -- _ � SEWER FOR LOT 1 � � ry��' _. .- � , � 13 - � �`'•�-y�..,... --- � '- F � - - - I , __�._ 1! ' - l � �{ . - i''� i ��`\ '�' " i .� _ .. _� '� � ,j� �. .< REL 7� EX. METER �� . . 4! 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Q� N o �, a - -- _ . _ c. —_ — -- _ _ - : _ _ � __ _ -_ NORTH 28th S1f2EET - -� � _ _ �rn- _ � ._: ,.,: ,_�.. - _ - - __. ..-___ _ - -- -- __ .-_�- - � -_ --- - - _ - . " - �- ,:' _ - - -' -- SITE PLAN Proposed Residences Project No_ 280o Park Avenue North Renton, Washington Drawing No_ 1 Robert M. Pride LLC Consulting Geotechnical Engineer PRELIMINARY CONDITIONS OF APPROVAL _ � , �� ; r'==", ,_.� (,_ ; , .._, `,_J �""� , ; :\ �� /� DEPARTMENT OF COMMUNITY ciry°f � .,Y -,. AND ECONOMIC DEVELOPMENT ��.`,,,'��.C��I :;',�,� ADMINISTRATIVE SHORT PLAT REPORT & DECISION A. SUMMARY AND PURPOSE OF REQUfST REPORT DATE: March 31, 2015 Project Name: Nantucket Short Plat Project Number: LUA14-001272; SHPL-A Project Monager: Kris Sorensen, Associate Planner Owner: Nantucket Avenue, LLC; 2812 257th PI SE; Sammamish, WA 98075 Applicant/Contact: Darrell Offe; Offe Engineers; 13932 SE 159th PI; Renton, WA 98058 Project Location: 2802 and 2820 Park Ave N Project Summary: The applicant is requesting Administrative Short Plat review. The two parcels at 2802 and 2820 Park Ave N in the Residential-8 (R-8) zone create a 62,520 sf (1.44-acre) site which is proposed to be subdivided into 8 residential lots and one stormwater tract. Density would be 7.1 du/ac where two existing homes would be demolished. Lot sizes would range from approximately 5,001 net sf to 5,444 net sf. One lot would gain direct access from Park Ave N and two lots would gain access from an access easement connected to Park Ave N with the remaining five lots gaining access from the proposed private street that ' connects to N 28th. The applicant submitted a tree inventory and retention plan, geotechnical report, and drainage report with the application. The proposal includes dedication of right-of-way along the public street frontages and construction of curb, gutter, planter strip for trees, and sidewalks. A stormwater tract for a vault is proposed in the southwest corner of the site. Of the 37 significant trees inventoried, 14 would be taken out for public and private streets with 29 new trees proposed to be planted within front yards and along the public and private streets. Exist. Bldg. Area SF: 3,860 sf Proposed New Bldg. Area (footprinrJ: N/A Proposed New Bldg. Area (grossJ: N/A Site Areo: 62,520 sf(1.435-acre) Tota! Building Area GSF: N/A �� - � � ° i � � .�� , i Project Location Map ! � City of Renton Department of Community&Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PL4T LUA24-001172;SHPL-A Report of March 31, 2015 Page 2 of 24 B. EXHIBITS: Exhibit 1: Administrative Short Plat Report and Decision Exhibit 2: Neighborhood Detail Exhibit 3: Short Plat Plan, prepared by Lanktree Land Surveying, date 1/15/15, Sheet 1 of 1 Exhibit 4: Landscape Plan, prepared by Jeff Varley Exhibit 5: Density Worksheet Exhibit 6: Tree Retention Worksheet Exhibit 7: Tree Retention Plan, prepared by Offe Engineers, date 1/28/15, Sheet 1 of 1 Exhibit 8: Drainage Report, prepared by Offe Engineers, date 10/14/14 Revised 1/30/15 Exhibit 9: Geotechnical Report, prepared by Robert Pride, date 11/7/14 Exhibit 10: Topography, Boundary, and Tree Survey, prepared by Lanktree Land Surveying, date 9/13/14, Sheet 1 of 1 Exhibit 11: Grading/Street Profile/Drainage/Utility Plan, prepared by Offe Engineers, date 1/27/15, Sheet 1 of 1 Exhibit 12: Vault Plan, prepared by Offe Engineers, date 1/27/15, Sheet 1 of 1 Exhibit 13: Project Narrative Exhibit 14: Schools for Attendance and Transportation, prepared by Renton School District, ' email date March 19, 2015 Exhibit 15: Public Comments-4 Exhibit 16: City Staff Responses to Public Comments Exhibit 17: Advisory Notes/ Review Comments Exhibit 18: Request by City to repair and replace stormwater facility and granting of request and allowance for work and access from Clover Creek Homeowners Association Exhibit 19: Aerial C. 6ENERAL INFORMAT/ON: Nantucket Avenue, LLC; 2812 257th PI SE; 1. Owner(s) of Record: Sammamish, WA 98075 2. Zoning Designation: Residential 8 (R-8) 3. Comprehensive Plan Land Use Designation: Residential Single Family (RSF) 4. Existing Site Use: Single Family Residential 5. Neighborhood Characteristics: Single Family Residential a. North: Sing/e family residential ond an undeveloped property used as a transit parking lot in R-8 zone b. East: Single family residentiol uses in R-8 zone c. South: Single famify residential uses in R-8 zone d. West: Single family residential use in R-8 zone 6. Access: Access is gained via Park Ave N and N 28th St 7. Site Area: 62,520 sf(1.435-acre) Short P/at Reoort LUA14-001272 DEPARTMENT OF COMMUNITY - ciry°f E .<=, AND ECONOMIC DEVELOPMENT �.�;��,� � .�� %;�� ADMINISTRATIVE SHORT PLAT REPORT & DECISION A. SUMMARY AND PURPOSE OF REQUEST REPORT DATE: March 31, 2015 Project Name: Nantucket Short Plat Project Number: LUA14-001272; SHPL-A Project Manoger: Kris Sorensen, Associate Planner Owner: Nantucket Avenue, LLC; 2812 257th PI SE; Sammamish, WA 98075 Applicant/Contact: Darrell Offe; Offe Engineers; 13932 SE 159th PI; Renton, WA 98058 Project Locotion: 2802 and 2820 Park Ave N Project Summary: The applicant is requesting Administrative Short Plat review. The two parcels at 2802 and 2820 Park Ave N in the Residential-8 (R-8) zone create a 62,520 sf (1.44-acre) site which is proposed to be subdivided into 8 residential lots and one stormwater tract. Density would be 7.1 du/ac where two existing homes would be demolished. lot sizes would range from approximately 5,001 net sf to 5,444 net sf. One lot would gain direct access from Park Ave N and two lots would gain access from an access easement connected to Park Ave N with the remaining five lots gaining access from the proposed private street that connects to N 28th. The applicant submitted a tree inventory and retention plan, geotechnical report, and drainage report with the application. The proposal includes dedication of right-of-way along the public street frontages and construction of curb, gutter, planter strip for trees, and sidewalks. A stormwater tract for a vault is proposed in the southwest corner of the site. Of the 37 significant trees inventoried, 14 would be taken out for public and private streets with 29 new trees proposed to be planted within front yards and along the public and private streets. Exist. B/dg. Area SF: 3,860 sf Proposed lllew Bldg. Area (footprint): N/A Proposed New 81dg. Area (grossJ: N/A Site Area: 62,520 sf(1.435-acre) Totol Building Area GSF: N/A . � � � � � r � 0 , Project Location Map City of Renton Department of Cammunity& Economic Development Administrative Shori P/at Report& Decrsion NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 3 of 24 D. HlSTOR/CAL/BACKGROUND: Action Land Use File No. Ordinance No. Date Comprehensive Plan N/A 5099 11/01/2004 Zoning N/A 510� 11/O1/2004 Annexation, Kennydale N/A 2531 12/31/1969 E. PUBLIC SERV/CES: 1. Utitities a. Water: Water service is provided by City of Renton. b. Sewer: Sewer service is provided by City of Renton. c. Surface/Storm Water: There is limited storm conveyance in Park Ave NE. 2. Streets: There are no street improvements fronting the site along both Park Ave N or N 28ih St. The streets are classified as Residential Access streets. 3. Fire Pratection: Service provided by City of Renton Fire Department. F. APPLlCABLE SECT10N5 OF THE RENTON MUNICIPAL CODE: 1. Chapter 2 land Use Districts I� a. Section 4-2-020: Purpose and Intent of Zoning Districts b. Section 4-2-070: Zoning Use Table c. Section 4-2-110: Residential Development Standards d. Section 4-2-115: Residential Design and Open Space Standards 2. Chapter 4 Property Development Standards a. Section 4-4-070: Landscaping Regulations b. Section 4-4-080: Parking, Loading, and Driveway Regulations c. Section 4-4-130: Tree Retention and Land Clearing Regulations 3. Chapter 6 Streets and Utility Standards a. Section 4-6-030: Drainage (Surface Water) Standards b. Section 4-6-060: Street Standards 4. Chapter 7 Subdivision Regulations a. Section 4-7-070: Detailed Procedures for Short Subdivisions b. Section 4-7-120: Compatibility with Existing Land Use and Plan —General Requirements and Minimum Standards c. Section 4-7-150: Streets—General Requirements and Minimum Standards d. Section 4-7-170: Residential Lots—General Requireme�ts and Minimum Standards 5. Chapter 9 Permits-Specific 6. Chapter 11 Definitions Short Plai Report LUA14-001272 City of Rentan Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001271;SHPL-A Report of March 31, 2015 Page 4 of 24 G. APPLICABLE SECT/ONS OF THE COMPREHENSIVE PL4N: 1. Land Use Element: Residential Single Family (RSF) land use designation 2. Community Design Element H. DEPARTMENT ANALYS/S: 1. Project Description/Back�round � The applicant, Darrell Offe, has requested preliminary short plat approval for an 8-lot short plat. The applicant is proposing to subdivide a 1.435-acre (62,520 sf) site zoned Residential-8 (R-8) dwelling units per acre (Exhibit 2) for single family residential development. The subject � site is a combination of two parcels at 2820 and 2802 Park Ave N. The site is located on the northeast corner of the intersection of Park Ave N and N 28th St. The application was originally submitted as a 10-lot subdivision (9 building lots and 1 tract) and has since been revised with one less single family lot. As a result of the reduction to 8 building lots and 1 tract, the subject project now qualifies as a short plat and no longer is considered to be a preliminary plat. Therefore, the land use review process has been changed accordingly. Two existing single family homes would be demolished as part of site development. The site , generally slopes from the northeast to the southwest. The stormwater vault facility is proposed at the low point of the site in the southwest corner (Exhibit 3). There is an ' approximate elevation change of 12 feet across the site (Exhibit 10). A new 26-foot wide private street would be constructed in an access and utility easement that connects to N 2gcn St (Exhibit 3) and runs a�ong the easterly border of the site. An 8-foot landscaped buffer with , trees, shrubs and ground cover would be located between the Private Street and easterly i abutting property (Exhibit 4). The site is located in the Aquifer Protection Zone 2. No other ' critical areas are identified on the subject site. i I City Council adopted Ordinance 5724 to provide interim zoning standards for the R-8 zone. The I legislation became effective at the time of Council approval on September 22, 2014. The Nantucket Plat application was determined complete on September 18, 2014, and therefore, is vested to the R-8 standards as were allowed prior to the Council adoption of Ordinance 5724. The site is designated Residential Single Family (RSF) in the City of Renton Comprehensive Land Use Plan. The subject site is located on the northeast corner of the intersection of Park Ave N j and N 28th St in the Kennydale Community Planning Area. The proposal for eight lots would arrive at a net density of 7.1 dwelling units per acre (du/ac) (Exhibit 5). Lot sizes for the residential parcels range from 5,001 net sf to 5,444 net sf in size. Access to the lots would be � varied: Lot 1 gaining access from Park Ave N; Lots 2 and 3 gaining access from an access easement on the stromwater Tract A; and Lots 4 through 8 gaining access from a new private street. Only Lot 1 would have a curb cut along a street for direct access to a garage, where all other lots would have driveways connected to the Private Street or access easement to reduce the amount of curb cuts across the public sidewalk. The private street is designed to provide the required fire emergency access with a required hammerhead turnaround located on Lots 7 and 8 (Exhibit 3). Dedication of right-of-way is proposed along both Park Ave N and N 28`h St. Short Plat Report LUA1 4-001 2 72 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14001272;SHPL-A Report of March 31, z015 Page 3 of 24 D. HISTORICAL/BACKGROUND: Action Land Use File No. Ordinance No. Date Comprehensive Plan N/A 5099 11/O1/2004 Zo n i n g N/A 5100 11/01/2004 Annexation, Kennydale N/A 2531 12/31/1969 � E. PUBLIC SERVICES: 1. Utilities a. Water: Water service is provided by City of Renton. b. Sewer: Sewer service is provided by City of Renton. c. Surface/Storm Water: There is limited storm conveyance in Park Ave NE. 2. Streets: There are no street improvements fronting the site along both Park Ave N or N 28`h St. The streets are classified as Residential Access streets. 3. Fire Protection: Service provided by City of Renton Fire Department. F. APPLICABtE SECT/ONS OF THE RENTON MUN/C/PAL CODE: 1. Chapter 2 Land Use Districts a. Section 4-2-020: Purpose and Intent of Zoning Districts b. Section 4-2-070: Zoning Use Table c. Section 4-2-110: Residential Development Standards d. Section 4-2-115: Residential Design and Open Space Standards 2. Chapter 4 Property Development Standards a. Section 4-4-070: Landscaping Regulations b. Section 4-4-080: Parking, Loading, and Driveway Regulations c. Section 4-4-130: Tree Retention and Land Clearing Regulations 3. Chapter 6 Streets and Utility Standards a. Section 4-6-030: Drainage (Surface Water)Standards b. Section 4-6-060: Street Standards 4. Chapter 7 Subdivision Regulations a. Section 4-7-070: Detailed Procedures for Short Subdivisions b. Section 4-7-120: Compatibility with Existing Land Use and Plan —General Requirements and Minimum Standards c. Section 4-7-150: Streets—General Requirements and Minimum Standards d. Section 4-7-170: Residential Lots —General Requirements and Minimum Standards 5. Chapter 9 Permits-Specific 6. Chapter 11 Definitions Short Plot Report LUA14-001272 City of Renton Department of Communify& Economic Deve/opment Administrative Short P/at Report& Decision NANTLICKET SHORT PLAT lUA14-001271;SHPI-A Report of March 31, 2015 Page 5 of 24 Public street improvements include instailation of planter strip, sidewalk, curb, and gutter along both street frontages on the project side. There are 37 significant trees identified on the survey (Exhibit 10J. The Tree Retention Worksheet (Exhibit 6) states that 14 trees would be removed for the construction of the public street and private street improvements {Exhibit 7}. There would be 29 new trees planted around the site with S existing significant trees retained (Exhibit 4). 2. Environmental Review Except when located on lands covered by water or sensitive areas, short plats are exempt from SEPA Environmental Review pursuant to WAC 197-11-800(6)(a). 3. Staff Review Comments Representatives from various city departments have reviewed the application materials to identify and address issues raised by the proposed development. These comments are � contained in the official file, and the essence of the comments have been incorporated into the appropriate sections of this report and the "Advisory Notes to the Applicant/Review , Comments" (Exhibit 17). I 4. Comment from the Public II� Staff received four comment letters (Exhibit 15) when the proposal was submitted originally as j a 9-lot proposal. The comment letters are still applicable as the project has been revised to include one less residential lot. Concerns range from tree retention, type of drainage facility, i sufficiency of parking, narrowness of N 28`h St, design of homes, and driveways to homes � across sidewalk areas. Staff provided responses to each of the letters (Exhibit 16). Specifics of I', the received comment letters are below: ''� � September 28, 2014 letter: The commenter has six main points; the lack of clarity of the 'I proposal for tree retention; access points to each of the (ots; and support for street improvements although added street lighting is not supported. A few of the comments relate to site design and design standards for build out. The commenter asks that the current fence heights for front yard setbacks be put on the plat due to lack of enforcement by the city, that the homes have a minimum of 18 feet setbacks to garages, and that the stormwater tract, if a pond, are usually ill-maintained and may be poorly designed as the corner is a gateway into the neighborhood. • September 30, 2014 letter: The commenter has three main concerns and asks for a covered vault rather than an open pond for the stormwater detention facility, or for better facility options for the project. Another concern is about home designs and that most homes are not varied enough in design. The last concern is about the N 28th St, where the street is currently very narrow, where improvements would stop at the end of the project and not continue (ie sidewalks), and that if parked cars area allowed on the road, there would be no room for two cars to pass. • October 8, 2014 letter: The commenter is concerned of the potential parking impacts and spillover parking needs of the new homes added to the a�ea. Specifically, new homes on the proposed private street and those that would face N 28th St. Additionally, the Short PJot Report LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short P/at Report& Decision NANTUCKET SHORT PLAT LUA14-001271;SHPL-A Report of March 31, 2015 Page 6 of 24 commenter states that N 28th St is currently not constructed to required City standards for widths, curbs, sidewalks, etc. • October 10, 2014 letter: The commenter has five main concerns, two of them regarding the stormwater tract and drainage. It is suggested that an open pond would be a hazard especially to children. It should be located in a different area of the project. Drainage is an issue and the new homes may cause continued flooding on N 28`h St and homes south of N 28tn St. Another comment is specific to the safety of N 28th St, with abutting homes pulling out onto it, increased traffic, parking along the street, and how the increase of new lots along the street would impact the street, parking, and neighboring properties that also use the street. One comment is related to site layout and the subdivided properties. The commenter states the plan does not fit with the existing neighborhood, as it is more dense and does not have yards or space similar to other homes in the surrounding area. 5. Consistency with Short Plat Criteria Approval of a short plat is based upon several factors. The following short plat criteria have been established to assist decision-makers in the review of the short plat: !. F/NDINGS: Having reviewed the written record in the matter, the City now enters the fotlowing: 1. Request: The project proponent has requested approval of a short plat subdivision of a 62,520 ' sf(1.435-acre) property in the Kennydale community into 8 lots suitable for development with single-family residential structures, where the two existing single-family dwellings would be demolished. The project would have a density of 7.1 du/ac based on the numbers provided on the Short Plat plan (Exhibit 3). 2. Application:The subject site is owned by Nantucket Avenue, LLC; 2812 257th PI SE; Sammamish, WA 98075. 3. Comprehensive Plan:The property has a Comprehensive Plan land use designation of Residential Single-Family (RSF). The proposed project furthe�s the objectives and policies of the RSF section of the Land Use Element of the Comprehensive Plan. The objectives and policies of the Community Design Element are also supported by the project as proposed. 4. Zoning: Objectives and policies of the RSF designation are implemented by standards and regulations of the Residential 8 zone. The project, as proposed, meets or exceeds the R-8 zone standards and regulations, if conditions of approval are met. 5. Subdivision Regulations: The short plat, as proposed, would meet the requirements of RMC 4- 7 Subdivision Regulations, if conditions of approval are met. 6. Existing land Uses: The site consists of one parcel with an existing family home and accessory structure, which is proposed to be retained. 7. Setbacks: Minimum setback requirements of the R-8 zone could be met for the new lots if all conditions of approval are met. 8. Short Plat Review Criteria: Approval of a plat is based upon several factors. The following short plat criteria, in the matrix below, have been established to assist decision-makers in the review of the plat. The criteria are evaluated on compliancy, and the depth of compliance is provided Short Plat Report LUA14-001172 City of Renton Deportment of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 5 of 24 Public street improvements include installation of planter strip, sidewalk, curb, and gutter along both street frontages on the project side. There are 37 significant trees identified on the survey (Exhibit 10). The Tree Retention Worksheet (Exhibit 6) states that 14 trees would be removed for the construction of the public street and private street improvements (Exhibit 7). There would be 29 new trees planted around the site with 5 existing significant trees retained (Exhibit 4). 2. Environmental Review Except when located on lands covered by water or sensitive areas, short plats are exempt from SEPA Environmental Review pursuant to WAC 197-11-800(6)(a). 3. Staff Review Comments Representatives from various city departments have reviewed the application materials to identify and address issues raised by the proposed development. These comments are contained in the official file, and the essence of the comments have been incorporated into the appropriate sections of this report and the "Advisory Notes to the Applicant/Review Comments" (Exhibit 17). 4. Comment from the Public Staff received four comment letters (Exhibit 15) when the proposal was submitted originally as a 9-lot proposal. The comment letters are still applicable as the project has been revised to include one less residential lot. Concerns range from tree retention, type of drainage facility, sufficiency of parking, narrowness of N 28th St, design of homes, and driveways to h�mes across sidewalk areas. Staff provided responses to each of the letters (Exhibit 16). Specifics of the received comment letters are below: • September 28, 2014 letter: The commenter has six main points; the lack of clarity of the proposal for tree retention; access points to each of the lots; and support for street improvements although added street lighting is not supported. A few of the comments relate to site design and design standards for build out. The commenter asks that the current fence heights for front yard setbacks be put on the plat due to lack of enforcement by the city, that the homes have a minimum of 18 feet setbacks to garages, and that the stormwater tract, if a pond, are usually ill-maintained and may be poorly designed as the corner is a gateway into the neighborhood. • September 30, 2014 letter:The commenter has three main concerns and asks for a covered vault rather than an open pond for the stormwater detention facility, or for better facility options fo� the project. Another concern is about home designs and that most homes are not varied enough in design. The last concern is about the N 28th St, where the street is currently very narrow, where improvements would stop at the end of the project and not continue (ie sidewalks), and that if parked cars area allowed on the road, there would be no room for two cars to pass. • October 8, 2014 letter: The commenter is concerned of the potential parking impacts and spillover parking needs of the new homes added to the area. Specifically, new homes on the proposed private street and those that would face N 28th St. Additionally, the Short Plat Report LUA14-001272 City of Renton Departmenf of Community& Economic Development Administratrve Short Pfat Report& Decisron NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31,2015 Page 7 of 24 through a denotation next to the criteria text as follows: (✓ Compliant; Note 1: Partially compliant; Note 2: Not compliant; Note 3: Compliance not yet demonstrated). 1. CONFORMANCE WITH THE COMPREHENSIVE PLAN: The site has the Comprehensive Land Use designation of Residential Single Family (RSF}. Land designated RSF is intended to be used for high quality detached, .single-family residential development organized into neighborhoods at urban densities. It is intended that larger subdivisions, infill development, and rehabilitation of existing housing be carefully designed to enhance and improve the quality of single family living environments. The proposal is consistent with the following Comprehensive Plan Land Use and Community Design Element policies, if all conditions of approval are met, unless noted otherwise: Policy LU-158. Net development densities should fall within a range of 4 to 8 dwelling units per acre in Residential Single Family Neighborhoods. Staff Comment: The resulting 1.435-acre site is located within the R-8 zoning ✓ classification. After subtracting 3,086 sf for proposed right-of-way dedications and 10,299 sf for the private srreet access eosement; the net square footoge of the site would be 49,135 sf(1.128 net acres). The 8 lor proposal would arrive at a net density of 7.1 dwelling units per acre (8 residential lots/1.128 acres= 7.1 du/acJ, which falls within the permitted density range for the R-8 zone. Objective CD-C. Promote reinvestment in and upgrade of existing residential neighborhoods through redevelopment of small, underutilized parcels with infill � development, modification and alteration of older housing stock, and improvements to streets and sidewalks to increase property values. Staff Comment: Eight new residential parcels would be creared for infill. Policy CD-12. Sidewalks or walking paths should be provided along streets in established neighborhoods, where sidewalks have not been previously constructed. Sidewalk width should be ample to safely and comfortably accommodate pedestrian traffic and, where practical, match existing sidewalks. Staff Comment: The subject site is a corner lot and has streer frontages on two public �, Residentia!Access streets, both Park Ave N and N 28`h St. Along Pork Ave N, there is approximately 200 feet in length and along N 28`h St there is approximately 257 feet in length (Exhibit 3J. There are no existing street improvements within either streets'right- of-way on the project side (Exhibit 17—Engineering Review, ExistiAg Conditions ✓ subsectianJ. There is limited street frontage improvements along the frontage of surrounding streets with the exception of that portion of Park Ave N, north of N 28rh PJ on the west side of the streei where a sidewalk is located rhat conrinues north. There is not sufficient existing right-of-way to provide the required street improvements in either Park Ave N or N 28`h St for curb, gutter, planter strip, and sidewalk. The applicant proposes to dedicate approximately 1.5 feet of frontage for public righr-of-way along Park Ave N ond approximately 10.5 feei of frontage for public right-of-way along N 28`h St. The required public right-of-way street improvements on the project side would include rhe required 13 feet poving from cenrerline, curb ond gutter, an 8 foot wide planter strip, and a 5 foot wide sidewa/k. Proposed streer improvements would include curb, gurter, planter strip and sidewalk for both screet frontages and as required ro meet the City's street standards snort Plar Report LUA14-oo1z72 '� . City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision '�i I �� NANTUCKET SHORT PLAT LUA14-001172;SHPL-A I Report of March 31, 2015 Page 8 of 24 � � � (Exhibit 11 — Utilities PlanJ. ' Policy CD-14. Infill development, defined as new short plats of nine or fewer lots, should ' be encouraged in order to add variety, updated housing stock, and new vitality to , ✓ neighborhoods. Staff Comment: The eight proposed lors would allow for updated housing stock. Policy CO-15. Infill development should be reflective of the existing character of established neighborhoods even when designed using different architectural styles, and /or responding to more urban setbacks, height or lot requirements. Infill development Note should draw on elements of existing development such as placement of structures, 3 vegetation, and location of entries and walkways, to reflect the site planning and scale of existing areas. Staff Comment:Detailed site and architectural designs will be reviewed to determine compatibility with the context of the site, at the time building permits are submitted. 2:: COMPLIANCE WITH THE UNDERLYING ZONING DESIGNATION: Objectives and policies of the Comprehensive Land Use Plan Residential Single Family designation are implemented by Residential 8 zoning (R-8). RMC 4-2-110A provides development standards for development within the R-8 zoning classification.The proposal is consistent with the following development standards if all conditions of approval are met, unless noted otherwise:`- Density: The minimum density allowed in the R-8 zone is 4 dwelling units per net acre (du/ac). The maximum density permitted in the R-8 zone is 8.0 du/as. Net density is calculated after the deduction of critical areas, areas intended for public rights-of-way, and private access easements. Calculations for minimum or maximum density that result in a fraction that is 0.50 or greater shall be rounded up to the nearest whole number. Those density calculations resulting in a fraction that is less than 0.50 shall be rounded down to the nearest whole number. `� Staff Comment: The applicant proposes to dedicate approximately 1.5 feet of frontage for public right-of-way along Park Ave N and approximafely 10.5 feet of frontage for public right-of-way along N 28th St(Exhi6it 3). The gross square footage of the subject site is 62,520 sf(1.435 acresJ and the net areo of the subject site with the private street area q,�d right-of-way dedications is 49,135 sf(1.128 acres). The 8-lot proposal would arrive at a net residential density of 7.1 dwelling units per acre (8 units/1.128 acres = 7.1 du/ac), which falls within the permitted density range for the R-8 zoning classification. Lot Dimensions:Staff Comment: R-8 Standards apply: Proposed Lots Net Lot Area Width minrmum Depth (Exhibrt 3) 4,500 sf 50 feet-interior; 60 65 feet minimum ✓ minimum feet-corner Lot 1 6,330 sf 60 ft 105 ft Lot 2 6,324 sf 50 ft 126 ft ' Sh�rt Plnt RPnnrt LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short P/ot Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 7 of 24 through a denotation next to the criteria text as follows: (✓ Compliant; Note 1: Partially compliant; Note 2: Not compliant; Note 3: Compliance not yet demonstrated). 1. CONFORMANCE WITH THE COMPREHENSIVE PLAN: The site has the Comprehensive Land Use designation of Residentiaf Single Family (RSF). Land designated RSF is intended to be used for high quality detached, single-family residential development organized into neighborhoods at urban densities.' It is intended that larger subdivisions, infill development, and rehabilitation of existing housing be carefully designed to enhance and improve the quality of single family living environments. The proposal is consistent with the following Comprehensive Plan Land Use and Community Design Element policies,if all conditions of approval are met, unless noted otherwise: Policy LU-158. Net development densities should fall within a range of 4 to 8 dwelling units per acre in Residential Single Family Neighborhoods. Staff Comment: The resu(ting 1.435-acre site is located within the R-8 zoning ✓ classification. Afrer subtracting 3,086 sf for proposed right-of-way dedications and 10,299 sf for the privote street access easement; the net square footage of the site would be 49,335 sf(1.128 net acresJ. The 8 lot proposal would arrive at a net density of 7.1 dwelling units per acre (8 residential lots/1.128 acres = 7.1 du/acJ, which falls within the permitted density range for the R-8 zone. Objective CD-C. Promote reinvestment in and upgrade of existing residential neighborhoods through redevelopment of small, underutilized parcels with infill � development, modification and alteration of older housing stock, and improvements to streets and sidewalks to increase property values. Staff Comment: Eight new residential parcels would be created for infill. Policy CD-12. Sidewalks or walking paths should be provided along streets in established neighborhoods, where sidewalks have not been previously constructed. Sidewalk width should be ample to safely and comfortably accommodate pedestrian traffic and, where practical, match existing sidewalks. Staff Comment: The subject site is a corner lot and has street frontages on two public Residential Access streets, both Park Ave N and N 28r''St. Along Park Ave N, there is approximately 200 feet in length and along N 28th St there is approximately 257 feet in length (Exhibit 3J. There are no existing street improvements within eirher streets'right- of-way on the project side (Exhibit 17—Engineerinq Review, ExistiAg Conditions ✓ subsection). There is limited street frontage improvements a/ong the fronrage of surrounding streets with the exception of that portion of Park Ave N, north of N 28th Pl on the west side of the streei where a sidewalk is located that continues north. There is not sufficient existing right-of-way to provide the required street improvements in either Park Ave N or IV 28th St for curb, gutrer, planter strip, and sidewalk. The applicant proposes to dedicate approximately 1.5 feet of frontage for public right-of-way along Park Ave N and approximately 10.5 feet of frontage for public right-of-way along N 28th St. The required public right-of-way street improvements on the project side would include the required 13 feet paving from centerline, curb and gutter, an 8 foot wide planter strip, and a 5 foot wide sidewolk. Proposed street improvements would indude curb, gutrer, planter strip and sidewalk for both streer fronrages and as required to meet rhe City's street srandards Short Plat Report LUA14-001272 City of Renton Department of Communrty&Economic Development Administrotive Short P/af Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 9 of 24 Lot 3 6,444 sf 81 ft 80 ft �I I Lot 4 (Corner) 5,988 sf 60 ft 129 ft � I Lot 5 5,001 sf 50 ft 129 ft ' Lot 6 5,484 sf 70 ft 120+ ft I, Lot 7 5,022 sf 50+ft 99+ft Lot 8 5,755 sf 50+ ft 150 ft Setbacks: The minimum front yard setback in the R-8 zone is 15 feet; minimum side yard is 5 feet and, minimum side yard along a street 15 feet for the primary structure; � minimum rear yard is 20 feet. li Note 3 Staff Comment: For all proposed lois there is sufficient area for new residential , structures that would comply with setbacks. All lots would have setbacks reviewed at time of building permi[. Building Standards: The R-8 zone permits one single family residential structure per lot. �� Accessory structures are permitted at a maximum number of two per lot with a I, maximum size of 720 square feet each, or a maximum of one per lot with a maximum of 1,000 square feet. Accessory structures are permitted only when associated with a primary structure located on the same parcel of land. The maximum building height in the R-8 zone is 30 feet. Buildin� hei�ht is based on the measurement of the vertical distance from the grade plane to the average height of the roof surface. The �rade plane is the average of existing ground level adjoining the building at exterior walls. Where the finished ground level slopes away from the exterior Note 3 �^'alls, the reference ptane shall be established by the lowest points within the area between the building and the lot line, or where the lot line is more than 6 feet from the building, between the building and a point 6 feet from the building. The maximum building coverage in the R-8 zone, for lots larger than 5,000 sf, is 35 percent or 2,500 sf, whichever is greater. The maximum impervious surface area is 75 percent. Staff Comment: For a!1 lots, building elevations,floor plans and a site plan, which would be used to determine building height, building coverage and impervious surface coverage, have not been submitted. They would be submitred for building permit review (compliance nor yec demonstratedJ. Landscaping: Landscaping is required for all subdivisions including short plats. A detailed landscape plan is usually required to be approved prior to issuance of street or utility Note 1 construction permits. A ten foot-wide on-site landscaped area is required along al� pubtic street frontages, with the exception of areas for required crosswalks and driveways. This landscaped area shall Short Plot Report LUA14-001172 City of Renton Department of Community&Economic Development Adminisirative Short P/at Report& Decision NANTUCKET SHORT PLAT LUA14-001172;SHPL-A Report of March 31, 2015 Page 10 of 24 be on-site and shall include a mixture of trees, shrubs and ground cover. Two trees are required in the front yard of each lot, when no street trees are provided in front of a residence. A minimum planting strip width between the curb and sidewalk are established according to the street development standards of RMC 4-6-060. Street trees and, at a minimum, groundcover per subsection RMC 4-4-070 L.2, are to be located in this area when present. Spacing standards shall be as stipulated by the Department of Community and Economic Development, provided there shall be a minimum of one street tree planted per address. Any additional undeveloped right-of-way areas shall be landscaped unless otherwise determined by the Administrator. Any stormwater facilities require a minimum amount of landscaping per RMC 4-4-070H.6. Refer to the City's Approved Tree list and spacing standards available through the Department of Community and i Economic Development and on the City's website. In addition, where there is insufficient right-of-way space or no public frontage, street trees are required in the front yard of each lot. Staff Commenf: The applicant submitted a conceptual landscape plan (Exhibit 4)for on- site landscape improvements, landscaping in rhe public street planting strips, and existing trees ro be retained. For the on-site improvements, the applicant has identified two trees to be planted in the front yard of each lot. Also, the application has identified a buffer strip between the private street and the abutting property to the east, where 6 Katsura trees are ro be located with groundcover consisting of grasses and shrubs. The landscape plan does not identify the required 10 foot buffer of/andscaping along public streets. Therefore, staff recommends, as a condition of approval, that a detailed landscape plan be submitted to the Current Planning Project Manager prior to ' construction permit approva!that identifies a mix of landscape plantings in the 10 foot buffer per RMC 4-4-070F.1. Additionally, the project has a stormwarer facility voult located in the sourhwesr corner of the site as identified on the landscape plan. The landscape plan does not identify landscaping plants on the proposed stormwater tract where the vault is ro be located (Exhibit 4J. A 10 foor landscape buffer is required along all public srreet frontoges where rhere is pervious surface.Addirionally, per RMC 4-4-070H.6, landscaping is required around stormwater facilities; alrhough no trees or shrubs shal!be located within 10 feet of any manmade drainage structure including a vault. Surrounding the proposed vault wouJd be pervious surface, which is required to be landscaped per RMC 4-4-070F.5. The vault p/an (Exhibit 12J identifies portions of the vault rhat may be elevated above the surface ground level, where this elevated porrion may be visible ro passers by. A vault should be locared underground and/orsoil should be graded to cover the vault. Once the vaulr is covered in soil rhe entire TracrA, with the exception of the access easement, should be able to be landscaped. Therefore, staff recommends as o condition of approval, that a detailed landscape plan be submitted to the Current Planning Project Manager prior to construction permit approval. The landscape plan shall identify a mix of landscape planrinqs in rhe stormwater tract and that the vault shall be designed to be fully covered with gound/soi!or an alternative method of screening approved by the Short Plat Report LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SNPL-A Report of March 31, 2015 Page 9 of 24 Lot 3 6,444 sf 81 ft 80 ft Lot 4 (Corner) 5,988 sf 60 ft 129 ft Lot 5 5,001 sf 50 ft 129 ft Lot 6 5,484 sf 70 ft 120+ft Lot 7 5,022 sf 50+ft 99+ft Lot 8 5,755 sf 50+ft 150 ft Setbacks: The minimum front yard setback in the R-8 zone is 15 feet; minimum side yard is S feet and, minimum side yard along a street 15 feet for the primary structure; minimum rea�yard is 20 feet. Note 3 Sfaff Comment: For al!proposed lots there is sufficient area for new residential structures that would comply with setbacks.All lots would have setbacks reviewed at time of building permit. Building Standards: The R-8 zone permits one single family residential structure per lot. Accessory structures are permitted at a maximum number of two per lot with a maximum size of 720 square feet each, or a maximum of one per lot with a maximum of 1,000 square feet. Accessory structures are permitted only when associated with a primary structure located on the same parcel of land. The maximum building height in the R-8 zone is 30 feet. Buildin� hei�ht is based on the measurement of the vertical distance from the grade plane to the average height of the roof surface. The �rade qlane is the average of existing ground level adjoining the building at exterior walls. Where the finished ground level slopes away from the exterior Note 3 Walls, the reference plane shall be established by the lowest points within the area between the building and the lot line, or where the lot line is more than 6 feet from the building, between the building and a point 6 feet from the building. The maximum building coverage in the R-8 zone, for lots larger than 5,000 sf, is 35 percent or 2,500 sf, whichever is greater. The maximum impervious surface area is 75 percent. Staff Comment: For all lots, building elevations,floor plans and a site plan, which would be used to determine building height, buiJding coverage and impervious surface coverage, have not been submitted. They would be submitted for building permit review (compliance not yet demonstratedJ. Landscaping: Landscaping is required for all subdivisions including short plats. A detailed landscape plan is usually required to be approved prior to issuance of street or utility Note 1 construction permits. A ten foot-wide on-site landscaped area is required along all public street frontages, with the exception of areas for required crosswalks and driveways. This landscaped area shall Short Plat Report LUA14-001272 City of Renton Depariment of Community& Economrc Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001172;SHPL-A Report of March 31, 2015 Page 11 of 24 Planning Division. Additionally, because the srormwater landscaping is required and maintenance of such landscaping is needed, staff recommends as a condition of approval, that the applicant add to the face of the plat rhat maintenance of the landscaping in Tract A shall be the responsibi(ity of al!home owners of rhe subdivision and that landscaping screening of any portions of the vault above grade is required. A stormwater detention pond, rather than the proposed vault, would not provide the same level of aesthetic benefits as the proposed vault does, which is integra! to the approval of the requesied short plat at the corner of this intersection of Park Ave N and N 28rn St. Staff received public comments regarding the potential impact of a pond, both as a potentral safety hazard and also as a negative aesthetic feature within public view at a public intersection. Therefore, staff recommends as a condition of approval, that any proposa/to convert tf�e stormwater vault within Tract A to a stormwater detention pond wou/d not be approved through this staff recommendotion, and would require o new � subdivision applrcation which would allow a new public review process. The street trees to be located within the right-of-way planting strips are identified as Katsura species. The City's Community Services and Forestry division state that Katsura would be allowed a/ong N 28rh St, but not a/ong Park Ave N, as there are overhead lines that may be impacted in the future (Exhibit 17—Community Services). Therefore, staff recommends as a condition of approval, that the Katsura trees not be used along Park Ave N, and thar an alternative smoller maruring species be provided. The City has an approved tree species list for street trees available on the Cify's website which can be used to identify a/ternative tree species for planting along Park Ave N. Tree Retention: Existing trees shall be retained where feasible. RMC 4-4-130 requires 30 percent of trees to be retained. If the required number of trees cannot be retained,they must be replaced according to RMC 4-4-130H. Staff Comment:According io the Tree Rerention Worksheet and Tree lnventory there are 37 significant trees with 6-inch diameter or greater on the site (Exhibits 5 and 8J. Fourteen trees would be excluded from retenrion requirements due to therr location within the areas where streer riqht-of-way and rhe privaie street are ro be developed. ✓ The Tree reteniion standards require a minimum of 30 percent of the trees after deduction which is 23 trees; which requires 7 on-site trees to be retained or replaced. The opplicant is proposing to retain 5 trees, including Spruce, Pine, Cedar, Cherry, and Hawthorne species. To replace ti►e 2 trees that cannot be retained, the applicant must provide 8 replacement trees where the applicant proposes to install a total of 29 new trees all 3 inches in caliper(Exhibit 4J. Trees would be planted in fronr yards of each lot, between the easterly neighboring property and the privare street, and wirhin the public streer planter strips. Based on the provided landscape plan the opplicant has complied with the tree retention standards of rhe code. Parking: Off-street parking for 2 vehicles per residential unit is required. ✓ Staff Comment: There is sufficient space to provide on-site parking as required for all Short Plat Report LUA14-001272 City of Renton Department of Community&Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 12 of 24 proposed lots. Parking is not allowed on the private street, hammerhead area of the private street, or the access easement on Tract A. The hammerhead turn around is to be clear at all times for fire and emerqency services. One of the public commenr concerns is regarding available parking. In the initial application for the 9 residential lot proposal, the applicant stated that each residential lot would have 4 vehicle parking spaces; two on the driveways, and two within the two-car garages for each home. Wirh 8 lots created for new homes rhrough the proposed shorr plat and four parking spaces on each, there would be approximately 32 vehicular sralls for each home. Therefore, each lot would meet rhe minimum of two on-sire parking stal/s for each residentia!unit. Critical Areas: The subject site is located within the Aquifer Protection Zone 2. The overall purpose of the aquifer protection regulations is to protect aquifers used as potable water supply sources by the City from contamination by hazardous materials. � Some uses are restricted that store, handle,treat, use, or produce substances that pose a hazard to groundwater quality. If fill is used for project development, a fill source statement would be required.The proposed building will be required to comply with applicable seismic building standards due to the presence of the seismic hazard area. - 3. DESIGN STANDARDS: Residential Design and Open Space Standards (RMC 4-2-115) are applicable in the R-8 zone,The Standards implement policies established in the Land Use and Community Design Elements ofthe Comprehensive Plan. Compliance with Site Design Standards must be demonstrated prior to approval of the subdivision. Compliance with Residential Design Standards would be verified prior to issuance of building permits. The proposal is consistent with the following design standards, unless noted otherwise: Lot Configuration: Standards apply to subdivisions of 4 or more street-fronting lots. Variety in the configuration of�ots enhances the image of variety of housing stock and helps minimize perceptions of monotony. One of the following is required: 1. Lot width variation of 10 feet minimum of one per four abutting street-fronting lots, or 2. Minimum of four lot sizes (minimum of 400 gross square feet size difference), or � 3. A front yard setback variation of at least 5 feet minimum for at least every four abutting street fronting lots. Staff Comment:All proposed lots abur a public or private street. The proposal meets the first criteria where a !ot width variation of 10 feet minimum of one per four abutting street fionting lots is met. Lots 5-8 are four abutting lots where there are lot widths that ranqe from approximately 50 up to 70 feet(Exhibit 3J. Garages: The minimization of the visual impact of garages contributes to creating communities that are oriented to people and pedestrians, as opposed to automobiles. One of the following is required (some options are not listed here due to lack of site Note feasibility, i.e. garages accessed from alley): 3 1. Recessed from the front of the house and/or front porch at least 8 feet, or 2. Located so the roof extends at least 5 feet (excluding eaves) beyond the front of the garage for at least the width of the garage, plus the porch/stoop area, or Short Plat Reoort LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA1 4-0 01 2 71;SHPL-A Report of March 31, 2015 Page 11 of 24 Planning Division. Addirionally, because the stormwater landscaping is required and maintenance of such landscaping is needed, staff recommends as a condition of approval, thar the applicant add to the face of the plat rhat maintenance of the landscaping in Tract A shall be the responsibility of all home owners of the subdivision and that landscaping screening of any portions of the vault above grade is required. A stormwater detention pond, rather than the proposed vault, would not provide the same level of aestheric benefits as the proposed vault does, which is integra!to the approval of the requested short plat at the corner of this intersection of Park Ave N and N Z8rn St. Staff received public comments regarding the potential impact of a pond, both as a potential safety hazard and also as a negative aesthetic feature within public view at a public intersection. Therefore, staff recommends as a condition of approval, that any proposa/to convert the stormwater vault within Tract A to a stormwater detention pond would not be approved through this staff recommendation, and would require a new subdivision application which wou/d allow a new public review process. The srreet rrees to be locared within the right-of-way planting strips are identified as Karsura species. The City's Community Services and Foresrry division state that Katsura would be allowed along N 28`h Sr, but not along Park Ave N, as there are overhead lines that may be impacted in the future (Exhibit 17—Community ServicesJ. Therefore, staff recommends as a condition of approval, that the Katsura trees nat be used along Park Ave N, and that an a/ternative smaller maturing species be provided. The City hos an approved tree species list for street trees available on the Ciry's websire which can be used to identify alternative tree species for planting along Park Ave N. Tree Retention: Existing trees shall be retained where feasible. RMC 4-4-130 requires 30 percent of trees to be retained. If the required number of trees cannot be retained,they must be replaced according to RMC 4-4-130H. Staff Comment:According to the Tree Rerention Worksheet and Tree /nventory rhere are 37 significant trees with 6-inch diameter or greater on the site (Exhibits 5 and 8). Fourteen trees would be excluded from retention requirements due to their location within the areas where street right-of-way and the private street are to be developed. ✓ The Tree retention standards require a minimum of 30 percent of the trees after deduction whrch is 23 trees; which requires 7 on-site trees to be retained or replaced. The applicant is proposing to retain 5 trees, induding Spruce, Pine, Cedar, Cherry, and Hawthorne species. To replace the 2 trees thar cannot be rerained, the applicant musr provide 8 replacemenr trees where the opplicant proposes to instal!a total of 29 new trees a113 inches in caliper(Exhibit 4). Trees would be planted in front yards of each lot, between the easterly neighboring property and the private street, and within the public street planter strips. 8ased on the provided landscope plan the applicant has complied with rhe rree retention standards of the code. Parking: Off-street parking for 2 vehicles per residential unit is required. ✓ Staff Comment: There is sufficientspace to provide on-site parking as required for all Short Plat Report LUA1 4-001 2 72 City of Renton Department of Community&Economic Development Administrative Short Plat Report& Decision NANTUCKET SNORT PLAT LUA24-001272;SHPL-A Report of March 31, 2015 Page 13 of 24 3. Sized so that it represents no greater than 50 percent of the width of the front fa�ade at ground level, or 4. Detached. The portion of the garage wider than 26 feet across the front shall be set back at least 2 feet. Staff Comment:For all lots, building plans, which would be used to determine visua! impact of garages, have not been submitted yet. They woufd be submitted for building permit review(compliance not demonstrated). Primary Entry: Entrances to houses shall be a focal point and allow space for social interaction. One of the following is required: 1. Stoop: minimum 4 feet by 6 feet and 12 inches above grade, or 2. Porch: minimum 5 feet deep and 12 inches abo�e grade. Exception: An ADA accessible route may be taken from a front driveway. Staff Comment:For a!1 lots, building designs, which would be used to evaluate design of entrances, have not been submitted yet. They would be submitted for building permit review(compliance not demonstratedJ. Lot 4 faces both N 28`h St. and the proposed private road. The traditional development pattern in the neighborhood is with homes that front N 28`h St; those homes are oriented towards the public street with entries, porches, and similar features. The current design of Lot 4 provides the !or widrh along rhe Note 3 private road and depth parallel to N 28=h St. This lot design could resu/t in a home thai is designed to front rhe private road instead of N 28`�St. An orienrotion rowards the private road would not be consistent with the existing charter of the established neighborhood (see Comprehensive Plan Policy CD-15J. Therefore, staff recommends as a condition of approval, that Lot 4 be required to hove its front entry facing N 28"'St;similar to Lot 3, where the minimum primory entry standards of Residential Design and Open Space Standards (RMC 4-2-115J be met with the home orientation towards N 28rh St. Furthermore, to ensure compatibility with the surrounding community the fa�ade of the homes froniing N 28`h St shall 6e designed to be consistenr with ihe orientation of the . surrounding cammunity. The building designs shall be reviewed and approved at the time of building permit application. Fa�ade Modulation: Buildings shall not have monotonous facades along public areas. One of the following is required: 1. An offset of at least one story that is at least 10 feet wide and 2 feet in depth on fa�ades visible from the street, or Note 2, At least a 2-foot offset of second story from first story on one street-facing fa4ade. 3 Staff Comment: For aN lots, building designs, which would be used to evaluate design of fa�ades, have not been submitted yer. They would be submitted for building permir review(compliance not demonsiracedJ. Windows and Doors: Windows and front doors are an integral part of the architectural Note ch�racter of a house. Windows and doors shall constitute 25 percent of all fa4ades Short Plat Report LUA14-001272 � City of Renton Department of Community& Economic Deve/opment Administrative Short P/at Report& Decision � NANTUCKET SHORT PLAT LUA14-001272;SHPL-A ' ._ Report of March 31, 2015 Page 14 of 24 �' 3 facing street frontage or the front yard for homes not facing a public street. Staff Comment: For all lots, building designs, which would be used to evaluate design of � windows and doors, have not been submitred yet. They would be submitted for building permit review(compliance not demonstratedJ. Staff recommends, as a condition of ,, approval, that the homes to be constructed on Lots 1-4 meet the minimum standards for ' the Windows and Doors reference in RMC 4-2-115, along the public street frontages and i not the Private Streer and/or access easements to provide for orientation of the front �, enrries towards the public srreets, as is similar with the surrounding development in the , neighborhood. Building designs would be reviewed at the time of building permit applicotion for the minimum standards for approval. Scale, Bulk,and Character: Neighborhoods shall have a variety of home sizes and � character. Abutting houses shall have differing architectural elevations. Note 3 Staff Comment: For all lors, building designs, which woufd be used ro evaluate scale, bulk, and character of structures, have nor been submitted yet. They would be submitted for building permit review(compliance not demonstrated). Roofs: Roof forms and profiles are an important architectural component. One of the following is required: 1. Hip or gabled roof with at least a 6:12 pitch for the prominent form of the roof Note (dormers, etc.), may have lesser pitch, or 3 2. Shed roof. Staff Comment:For all lots, building designs, which would be used to evaluate roof forms, have not been submitted yet. They wou/d be submitted for building permit review (compliance not demonstratedJ. Eaves: Eaves and overhangs act as unifying elements in the architectural character of a house. Both of the following are required: 1. Eaves projecting from the roof of the entire building at least 12 inches with horizontal fascia or fascia gutter at least 5 inches deep on the face of all eaves, and Note 2• Rakes on gable ends must extend a minimum of 2 inches from the surface of 3 exterior siding materials. Staff Comment:For a!!lots, building designs, which would be used to evaluate design of eaves and overhangs, have not been submitted yet. They would be submitted for building permir review (compliance nor demonstrated). Architectural Detailing: Architectural detailing contributes to the visual appeal of a house and the community. If one siding material is used on ar�y side of the dwelling that is two stories or greater in height, a horizontal band that measures at least 8 inches is Note required between the first and second story. Also, one of the following is required: 3 1. Minimum 3-1/2 inch trim surrounds all windows and details all doors, or 2. A combination of shutters and minimum 3-1/2 inch trim details all windows and minimum 3-1/2 inch details all doors. Short P/at Renort LUA14-001272 City of Rentan Department of Community&Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LL/A14-001272;SHPL-A Report of March 31, 2015 Page 13 of 24 � 3. Sized so that it represents no greater than 50 percent of the width of the front fa4ade at ground le�el, or 4. Detached. The portion of the garage wider than 26 feet across the front shall be set back at least 2 feet. Staff Comment: For all lots, building plans; which would be used to derermine visual _,f impact of garages, have not been submitted yet. They would be submitted for building � permit review (compliance not demonstrated). Primary Entry: Entrances to houses shall be a focal point and allow space for social interaction. One of the following is required: 1. Stoop: minimum 4 feet by 6 feet and 12 inches above grade, or 2. Porch: minimum 5 feet deep and 12 inches above grade. � �j Exception: An ADA accessible route may be taken from a front driveway. 1 Staff Comment:For all lots, building designs, which would be used to evaluare design of entrances, have not been submitted yet. They would be submitted for building permit review(compliance not demonstratedJ. Lot 4 faces both N 28�h St. and the proposed private road. The traditional developmenr pattern in the neighborhood is with homes that front N 28rh St; those homes are oriented towards the public street with entries, -' _,� porches, and similar features. The current design of Lor 4 provides the lot width along the ' Note 3 private road and depth para!!el to N 28�'St. This lot design could result in a home that is ' designed to front the private road instead of N 28th St. An orientation towards the private �; road would not be consistent with the existing charter of the established neighborhood (see Comprehensive Plan Policy CD-15J. Therefore, staff recommends as a condition of approval, that Lot 4 be reguired to have its front entry facing N 28`h St;similar to Lot 3, — where the minimum primary entry standards of Residential Design and Open Space _ % Standards (RMC 4-2-115J be met with the home orientation towards N 28rh St. '; Furthermore, ro ensure compatibility with the surrounding community the fa�ade of the �, homes fronting N 28rh St shal!be designed to be consistenr with the orientation of the , ' 1 surrounding community. The building designs shall be reviewed and approved at the - time of building permit application. ' �� ) Fa�ade Modulation: Buildings shall not have monotonous facades along public area5. ' One of the following is required: _? 1. An offset of at least one story that is at least 10 feet wide and 2 feet in depth on % fa�ades visible from the street, or \�� Note 2, At least a 2-foot offset of second story from first story on one street-facing fa�ade. 3 Staff Comment: For all lors, building designs, which would be used ro evaluate design of fa�ades, have not been submitted yet. They would be submitted for building permit ' _� review(compliance not demonstratedJ. _' � i Windows and Doors: Windows and front doors are an integral part of the architectural , �, Note character of a house. Windows and doors shall constitute 25 percent of all fa�ades ,I Short Plat Report LUA14-001272 , City of Renton Deportment of Community&Economic Development Admrnistrative Short Plot Report& Decision NANTUCKET SHORT PLAT LUA14-001271;SHPL-A - Report of March 31, 2015 Page 15 of 24 r" �� Staff Comment: For a!I lots, building designs, which would be used to evaluate architectural detailing, have not been submitted yet. They would be submitted for ti building permit review(compliance not demonstratedJ. r Materiais and Color: A variety of materials and color contributes to the diversity of ; housing in the community. Abutting houses shall be different colors. Color palettes for all new dwellings, coded to the building elevations, shall be submitted for approval. _ Additionally, one of the following is required: 1. A minimum of 2 colors shall be used on the building (a main color with different Note trim color is acceptable), or 3 2. A minimum of 2 different siding materials shall be used on the building. One siding material shall comprise a minimum 30 percent of the street-facing fa�ade. If masonry siding is used, it shall wrap the corners no less than 24 inches. Staff Comment: For all lots, building designs, which wou/d be used to evaluate material and color choices, have not been submitred yet. They would be submitred for building permit review(compliance not demonstratedJ. 4. COMPLIANCE WITH SUBDIVISION REGULATIONS: RMC4-7 Provides review criteria for proposed subdivisions. The proposed project is consistent with the following subdivision regulations if all conditions of app.roval a�e complied with: ' - - ' Access: Each lot must have access to a public street, private road, or by a private access ;' easement per the requirements of the street standards. Per RMC 4=4-0801.i.iii, ; Driveways shall not be closer than five feet to any property line. Curb cuts to residential lots from private and public streets shall be no more than 9-feet maximum width for `` ' single vehicle garages end no more than 16-feet maximum width for double vehicle garages. � Staff Comment:Access to the lots would be either from a priva[e street that connects to - N 28`h St or to Pork Ave N(Exhibit 3J. Lot 1 would gain direct access to Park Ave N. Lots 2 ` and 3 would gain access from an access easement across the stormwoter tract at rhe ' southwest corner of ihe site. Lois 4 through 8 would gain access from the new private �" street located along rhe easterly sire boundary. To ensure that additional curb curs are not added to rhe public street, staff recommends, as a condition of approval, thar a note `� be added to the face of the plat staring that only Loi 1 is ro gain direct access onto a public street and that the remainder of the lots shal!gain access from either a private srreet ond/or occess easemenr. The Fire Department requires a fire apparatus turnaround for this short plot to provide for access to Lots 5 through 8(Exhibit 17J. A 26 foot easement is required for private streets and 20 foot paved path that meets Fire Department construction requirements. The proposal provides for the minimum 20 foot paved width required by fire as ihis width is part of the proposed 26 foot wide private streec that connects to N 28th Sr. The required fire access hommerhead turnaround area is identified on Lot 7 and Lot 8 in rhe northeast corner of rhe subject site (Exhibit 3). The widrh of curb cuts wil!be reviewed at time of building permit review. Short Plat Report LUA14-001272 City of Renton Department of Community& Economic Development Admrnistrative Short P/at Report& Decision NANTUCKET SHORT PL4T LUA14-001272;SHPL-A Report of March 31, 2015 Page 16 of� �' Private srreets and private access easemenrs are to be mainrained by the private II, properties using the access, therefore staff recommends, as a condition of approval, rhat ', the face of the plat have o statement to the effect that the private street and private ', � shared access easements be maintained by the property owners of the subdivision wrth I such language reviewed and approved by the Current Planning Project Manager prior to �', short plat recording. I, Alleys: Alley access is the preferred street pattern for all new residential development in � the R-8 zone. New residential development in areas without existing alleys shall utilize '� alley access for interior lots. The City will consider the fotlowing factors in determining �', whether the use of alleys is not practical: A) Size:The new development is a short plat; B) ! Topography: The topography of the site proposed for development is not conducive for I an alley configuration; C) Environmental Impacts: The use of alleys would have more of a �I negative impact on the environment than a street pattern without alleys. �� `� Sta$Comment: The proposal is required ro consider alleys as part of rhe layour because I, the project is 6 du/ac or greater. Pursuant to criterion A, the subject project is a short ', plat, therefore an alley is not required. However, the applicant has elecred to access Lots �'� 2 and 3 from a private access easement to allow for a rear-loaded garage and Lot 4 from ' the private street to allow for a side-loaded garage. This configuration reduces the ', number of curb cuts along the public street frontage which is a similar result when an ', alley is provided. However, to ensure the homes are designed to appear as though some '� homes have alley access, staff recommends a condition of approval, that Lots 2 and 3 provide�ear loaded garages and Lot 4 provide a side loaded garage. ' Streets: The short plat is the subdivision of a corner lot with street frontage along Park Ave N and N 28th St. Street improvements are required. Street lighting is required. ' Staff Comment: The site is a corner lot with frontage on both Park Ave N and N 28th St which are both classified as residential access streets (Exhibit 17- TransportationJ. Currently, there are no street improvements along the lot frontage. The applicant has proposed is to provide the required paving, curb, gutter, planterstrip, and sidewalk along the street frontage (Exhibit 11). Corner lots require a minimum radius of 25 feet. Both streets require street dedicarion as proposed on the short plat plan (Exhibit 3) which would provide for the minimum 25 foot radius. ✓ Existing right-of-way width in Park Ave N fronfing the site is 50 fee�. Park Ave N is classified as a residential access street. To meet the City's complete street standards, street improvements including a pavement width of 26 feet, curb, gutter, an 8 foot planter strip, 5 foot sidewalk, and storm drainage improvements are required to be constructed in the right-of-way fronting the site per RMC 4-6-060. To build this street section, approximately one and half feet of right-of-way will be required to be dedicated to the City along the project side in Park. Street section for Park Ave N will be a 53 foot right-of-way. Half street improvements are required and are shown on the plans. Short Plat Report LUA14-001272 City of Renton Department of Communrty& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001172;SHPL-A Report of March 31, 2015 Page 15 of 24 Staff Comment: For all lots, building designs, which would be used to evaluate architectura!detailing, have not been submitted yet. They would be submitted for building permit review(compliance not demonstrated). Materials and Color: A variety of materials and color contributes to the diversity of housing in the community. Abutting houses shall be different colors. Color palettes for all new dwellings, coded to the building elevations, shall be submitted for approval. Additionally, one of the following is required: 1. A minimum of 2 colors shall be used on the building (a main color with different Note trim color is acceptable), or 3 2. A minimum of 2 different siding materials shall be used on the building. One siding material shall comprise a minimum 30 percent of the street-facing fa�ade. If masonry siding is used, it shall wrap the corners no less than 24 inches. Staff Comment: For all lots, building designs, which would be used to evaluate material and color choices, have not been submitted yet. They would be submitted for building permit review (compliance nor demonstratedJ. 4. COMPLIANCE WITH SUBDIVISION REGULATIONS: RMC 4-7 Provides review criteria for proposed subdivisions. The proposed project is consistent with the following subdivision regulations if all conditions of approval are complied with: Access: Each lot must have access to a public street, private road, or by a private access easement per the requirements of the street standards. Per RMC 4-4-0801.1.iii, Driveways shall not be closer than five feet to any property line. Curb cuts to residential lots from private and public streets shall be no more than 9-feet maximum width for single vehicle garages and no more than 16-feet maximum width for double vehicle garages. Staff Comment:Access to the lots would be either from a private street tf�at connecrs to N 28rh St or to Park Ave N(Exhibit 3). Lot 1 would gain direct access to Park Ave N. Lots 2 and 3 would gain access from an access easement across the stormwater tract at the southwest corner of the site. Lots 4 through 8 would gain access from the new privare street located along the easterly site boundary. To ensure that additional curb cuts are not added to the public street, staff recommends, as a condition of approval, that a note `� be added to the face of the plat stating that only Lot 1 is to gain direct access onto a public street and that the remainder of the lots shall gain access from either a private srreet ond/or access easement. The Fire Department requires a fire apparatus turnaround for this short plat to provide for access to tots 5 through 8 (Exhibit 17J. A 26 foot easemenr is required for private streets and 20 foot paved path that meets Fire Department construction requirements. The proposa!provides for the minimum 20 foot paved width required by fire as this width is part of the proposed 26 foot wide privote street that connects to N 28`h St. The required fire access hammerhead turnaround area is identified on Lot 7 and Lot 8 in the northeast corner of the subject site (Exhibit 3). The width of curb cuts will be reviewed at time of building permit review. Short Plat Report LUA14-001172 City of Renton Department of Community&Economic Developmeni Adminrstrative Short Plot Report& Decrsion NANTUCKET SHORT PLAT LUA14-001271;SHPL-A Report of March 31,2015 Page 17 of 24 Existing right-of-way width in IV 28th St fronting the site is 25 feet. N 28th St is classified � as a residenrial access streei. To meei the City's comp/ere street standards, street improvements including a pavement width of 26 feet, curb, gutter, an 8 foot planter strip, 5 foot sidewo/k, and storm drainage improvements are required to be constructed in rhe right of way fronting the site per RMC 4-6-060. To build this street section approximately 10.5 feet of right-of-way dedication is required along the project side. The dedication is shown on the plans. Streei section for N 28th St wil!be a 53 foot right-of- way. Half street improvements are required and are shown on the p/ans. Therefore, through the proposed dedication for right-of-way and proposed installarion of street frontage improvements, the subject proposa/would provide the required half- street improvements to meet the City's complete street standards of RMC 4-6-060. Blocks: Biocks shail be deep enough to allow two tiers of lots. N/A Staff Comment: No new blocks are proposed, therefore the criteria does not apply. 5. AVAILABILIIY AND IMPACT ON PUBLIC SERVICES: � Police: The Renton Police Department has commented that the proposed project would have minimal impacts on police service (Exhibit 17 - Police Review subsection). Fire: Sufficient resources exist to furnish services to the proposed development, subject to the condition that the applicant provides Code required improvements and fees (Exhibit 17 - Fire Review subsection). The fire flow requirement for a single-family residence is minimum 1,000 gpm for structures up to 3,600 sf, including attached garage and basement. If dwellings exceed 3,600 sf, a minimum of 1,500 gpm would be required. A minimum of one fire hydrant is ✓ required within 300 feet ofthe proposed buildings and two hydrants if the fire flow requirement increases to 1,500 gpm. Fire Impact Fees shall be paid prior to issuance of building permits. This fee is assessed per new single family lot at the rate in place at the time the building permit is issued. For 2015 the fee is $495.10 per new single family lot and fees may increase year to year. The fee shall be payable to the City as specified by the Renton Municipal Code prior to I building permit issuance. Schools: It is anticipated that the Renton School District can accommodate any additional students generated by this proposal at the following schools (Exhibit 14): Kennydale Elementary (0.30 miles from the subject site), McK�ight Middle School (1.06 miles from the subject site) and Hazen High School (2.5 miles from the subject site). ✓ RCW 58.17.110(2) provides that no subdivision be approved without making a written W�tn finding of adequate provisions for safe walking conditions for students who walk to and Condition ,r from school and/or bus stops. Kennydale Elementary is within walking distance of the • Approval subject site (Exhibits 14). Bussing would be provided for the middle and high schools (Exhibit 14). With the required street improvements for this project for both Park Ave N and N 28th St, new sidewalks will be installed where they currently do not exist. There are existing sidewalks on the west side of Park Ave N from N 29th PI to the intersection of Park Ave N Short Plat Report LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 18 of 24 and N 30`h St where crosswalks exist. On the eastside of Park Ave N, there would be a gap where sidewalks do not exist and are not part of the subject project. Sidewalks do not exist at the frontages for addresses 2900 Park Ave N, 2814 Park Ave N, and 2808 Park Ave N. Although there are no sidewalks along each of the properties 2900, 2814, and 2808, there is sufficient walkway between the white stripe of the travel lane and property boundaries for a walking route to the intersection of Park Ave N from n 30ih St. From the subject site, whether students use the east or west side of Park Ave N, they would travel to the intersection of N 30th St and head east to connect to Kennydale Elementary School, where there are sidewalks and crosswalks available, which provide for the safe route to school requirement for students walking. The school district has provided information that the crosswalks on the south side of NE 30th St for the Interstate 405 on-ramp and off-ramp should be enhanced with new, brighter green color for the crosswalk striping, for a needed improvement for the safe walking route to Kennydale. Therefore, staff recommends, as a condition of approval prior to final short plat recording, that if the existing crosswalks are within the jurisdiction of City of Renton � for striping, that the applicant work with Public Works to provide new or enhanced striping to the two crosswalks on the southside of NE 30th St for the on and off-ramp travel ways from the interstate. School impact fees shall be paid prior to issuance of building permits. This fee is assessed , per new single family lot at the rate in place at the time the building permit is issued. ' For 2015 the fee is $5,541 per dwelling and shall be paid prior to building permit issuance. Fees change year to yea�. Parks: Although there would be no significant impacts to the City of Renton Park System anticipated from the proposed project, an impact fee is required of all new residential development. `� Park impact fees shall be paid prior to issuance of building permits. This fee is assessed per new single family lot at the rate in place at the time the building permit is issued. For 2015 the fee is $1,395.25 and fees change year to year. Stormwater: A drainage report was submitted by Offe Engineers PLLC, dated October 14, 2014 and Revised January 30, 2015. The drainage report complies with the 2009 King County Surface Water Manual and City Amendments. All core and six special requirements have been discussed in the report. The 1.4-acre site is located within the East Lake Washington sub basin. Based on the City's flow control map, the 8-lot short plat, falls within the Flow Control Standard, Existing Site Condition. The site has two existing homes that will be demolished. The project is exempt from detention because the difference between the 100 year developed run off and existing condition runoff is less than 0.10 cfs. A combined detention and water quality vault,to be installed in proposed Tract A, located at the southwest corner of the site will be provided. It will � treat the new PGIS and impervious surfaces created by off-site frontage improvements, paving in Park Ave N and N 28th St, and the runoff from the new private road. Discharge � from the vault will be through a new 12-inch pipe crossing the roadway at the corner of N 28th St and Park Ave N.The new 12-inch pipe will connect to an existing 6-inch concrete pipe where it outfalls into a ravine. The flows follow the path of the ravine down the hill to the west where it eventually outfalls into Lake Washington. The sno�r Piar Report tuala-oolz�z City of Renton Department of Community& Economic Development Admrnistratrve Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SNPL-A Report of March 31, 2015 Page 17 of 24 Existing right-of-way width in N 28th St fronting the site is 25 feet. N 28th St is classified as a residential access street. To meet the City's complete street standards, street improvements including a pavement width of 26 feet, curb, gutter, an 8 foot p/anter strip, 5 foot sidewalk, and storm drainage improvements are required to be constructed in the right of way fronting ihe site per RMC 4-6-060. To build this street section approximately 10.5 feet of right-of-way dedication is required along the project side. The dedication is shown on the plans. Street section for N 28th St will be a 53 foot right-of- way. Half street improvements are required and are shown on the plans. Therefore, through the proposed dedication for right-of-way and proposed installation of street frontage improvements, the subject proposal wou/d provide the required half- street improvements to meet the City's complete street standards of RMC 4-6-060. Blocks: Blocks shall be deep enough to allow two tiers of lots. N/A Staff Comment: No new blocks are proposed, therefore the criteria does not apply. 5. AVAIIABILITY AND IMPACT ON PUBLIC SERVICES: � Police: The Renton Police Department has commented that the proposed project would have minima) impacts on police service (Exhibit 17 - Police Review subsection). Fire: Sufficient resources exist to furnish services to the proposed development, subject to the condition that the applicant provides Code required improvements and fees (Exhibit 17 - Fire Review subsection). The fire flow requirement for a single-family residence is minimum 1,000 gpm for structures up to 3,600 sf, including attached garage and basement. If dwellings exceed 3,600 sf, a minimum of 1,500 gpm would be required. A minimum of one fire hydrant is ✓ required within 300 feet of the proposed buildings and two hydrants if the fire flow requirement increases to 1,500 gpm. Fire Impact Fees shall be paid prior to issuance of building permits. This fee is assessed per new single family lot at the rate in place at the time the building permit is issued. For 2015 the fee is $495.10 per new single family lot and fees may increase year to year. The fee shall be payable to the City as specified by the Renton Municipal Code prior to building permit issuance. Schools: It is anticipated that the Renton School District can accommodate any additional students generated by this proposal at the following schools (Exhibit 14): Kennydale Elementary (0.30 miles from the subject site), McKnight Middle School (1.06 miles from the subject site) and Hazen High School (2.5 miles from the subject site). �/ RCW 58.17.110(2) provides that no subdivision be approved without making a written W�tn finding of adequate provisions for safe walking conditions for students who walk to and Condition of from school and/or bus stops. Kennydale Elementary is within walking distance of the Approval subject site (Exhibits 14). Bussing would be provided for the middle and high schools (Exhibit 14). With the required street improvements for this project for both Park Ave N and N 28th St, new sidewalks will be installed where they currently do not exist. There are existing sidewalks on the west side of Park Ave N from N 29`h PI to the intersection of Park Ave N Short Plat Report LUA14-001272 City of Renton Department of Community&Economic Development Administrative Short P/at Report& Decrsion NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 19 of 24 applicant has received approval to repair and replace the existing 6 inch pipe at the southwest corner of the intersection of N 28th St and Park Ave f1�(property PID 164450UNIT). The City made a request to access the private property as the City storm pipe is in disrepair and is required to be fixed (Exhibit 18). The owners of the private property ha�e confirmed that the repair and replacement is allowed for the stormwater pipe, and have confirmed that access to perform the work is granted (Exhibit 18). A geotechnical report, dated November 7, 2014, was submitted by Robert M. Pride LLC (Exhibit 9). The site slopes east to west. The field study included four exploration pits on the site. Test pits up to 9 feet deep were dug in native soils. No ground water was encountered. Soil type encountered was silty sands, sands, and gravel. Soil type is classified as Qvr "recessional sands—sands and gravels." The geotechnical engineer supports the feasibility of 100% infiltration onsite where the sands and sandy gravels below the topsoil will perform adequately for storm water discharge into these granular sediments. Appropriate individual lot flow control Best Management Practices (BMPs) are required (Exhibit 17-Surface Water). In the Technical Drainage Report (Exhibit 8, Section 4: Flow Control Review), BMPs are proposed as the engineer proposes to provide full infiltration on each individual lot using dry wells or infiltration trenches per the 2009 City of Renton Drainage Manual. The drainage engineer states that the proposal is to mitigate infiltration on all the lots using "Full Infiltration" of developed impervious surfaces (Exhibit 8, Section 4: Flow Control Review). Stormwater drainage plans for individual lots will be required prior to issuance of construction permits.The Surface Water System Development fee for 2015 is $1,350.00 per lot and fees are payable prior to issuance of construction permits. Water Service:The project is located in City of Renton service area (Exhibit 17 - Engineering Review-Water subsection). There is a 12-inch ductile iron water main in N 28tn St and a 12-inch water main in Park Ave N. The project is in the 320 water pressure zone. All new construction must have a fire hydrant capable of delivering a minimum of 1,000 gpm, and must be located within 300 feet of all structure.There are fire hydrants in the vicinity that may be counted towards the fire protection of this project, but is subject to verification for being within 300 feet of the nearest corner of all buildings. Existing hydrants counted as fire protection will be required to be retrofitted with a 5- � inch quick disconnect storz fitting if not already in place. A water main extension is required on site to serve Lots 5 through 8 as identified on the plans (Exhibit 11). System development fees for water are based on the size of the new domestic water meter that will serve the new home on each new lot. Fees for%-inch or 1-inch water meter install are$3,090.00 per lot for 2015. Credit will be given for the domestic water serving the existing homes. Fees are payable prior to issuance of the � construction permit. 2015 fees for a %-inch meter drop installed by the City are $400.00. 2015 fees for a 1-inch meter drop installed by the City are $460.00. Fees change year to year. � Sanitary Sewer Service: The project is provided sewer service by the City of Renton (Exhibit 17 - Sanitary Service). There is an 8-inch sewer main in N 28th St and an 8-inch — Short Plat Report LUA14-001172 ;' City of Renton Deportment of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SNPL-A � Report of March 31, 2015 Page 20 of 24 I sewer main in Park Ave N. A sewer main extension is required to serve lots 5 through 8 as identi�ed on the civil plan (Exhibit 11). System development fee for sewer is based on the size of the new domestic water to serve the new home on each new lot. All short plats shall provide separate side sewer stubs to each building lot prior to recording of the short plat. Sewer fee for a %-inch or 1-inch meter install is $2,135.00. Credit will be given to the , existing home if it is connected to sewer. Fees are payable prior to issuance of construction permits. �: Transportation: Impacts to the city transportation system are expected, due to r' increased vehicle trips to and from the proposed project. Corner lots require a minimum radius of 25 feet (Exhibit 17 -Transportation/Street). I Existing right of way width in Park Ave N fronting the site is 50 feet. Park Ave N is classified as a residential access street.To meet the City's complete street standards, street improvements including a pavement width of 26 feet, curb, gutter, an 8 foot � planter strip, 5 foot sidewalk, and storm drainage improvements are required to be constructed in the right of way fronting the site per RMC 4-6-060. To build this street section, approximately one and half feet of right-of-way will be required to be dedicated to the City along the project side in Park. Street section for Park Ave N will be a 53-foot �, right-of-way. Half street improvements are required and are shown on the plans. '� Existing right of way width in N 28th St fronting the site is 25 feet. N 28th St is classified as a residential access street. To meet the City's complete street standards, street improvements including a pavement width of 26 feet, curb, gutter, an 8 foot planter strip, 5 foot sidewalk, and storm drainage improvements are required to be constructed in the right-of-way fronting the site per RMC 4-6-060. To build this street section approximately 10.5 feet of right-of-way dedication is required along the project side. The dedication is shown on the plans. Street section for N 28th St will be a 53-foot right-of- way. Half street improvements are required and are shown on the plans. The current transportation impact fee rate for 2015 is $2,214.44 per new single family home. The transportation impact fee that is current at the time of building permit application will be levied. Payment of the transportation impact fee is due at the time of issuance of the building permit. Credit will be given to the existing home. 9. System Development Charges:The Surface Water System Development Fee for 2015 is $1,350.00 per new lot. Water and Sanitary Sewer are provided by City of Renton. Sewer fee for a 3/-inch or 1-inch meter install is $2,135.00. 10. Public Utilities: Sufficient public utilities would be available for the development of homes on the proposed lots if all conditions of approval are met. 11. Street Frontage Improvements: Improvements for both Park Ave N and N 28th St are required to include 13 feet of paving from centerline, curb and gutter, and 8-foot planter strip with trees, a 5-foot sidewalk, and storm drainage improvements according to City code. Short Plat Report LUA24-001272 City of Renton Departmeni of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 19 of 24 applicant has received approval to repair and replace the existing 6 inch pipe at the southwest corner of the intersection of N 28th St and Park Ave 11�{property PID 164450UNIT). The City made a request to access the private property as the City storm pipe is in disrepair and is required to be fixed (Exhibit 18). The owners of the private property have confirmed that the repair and replacement is allowed for the stormwater pipe, and have confirmed that access to perform the work is granted (Exhibit 18). A geotechnical report, dated November 7, 2014, was submitted by Robert M. Pride LLC (Exhibit 9). The site slopes east to west. The field study included four exploration pits on the site. Test pits up to 9 feet deep were dug in native soils. No ground water was encountered. Soil type encountered was silty sands, sands, and gravel. Soil type is classified as Qvr "recessional sands—sands and gravels." The geotechnical engineer supports the feasibility of 100% infiltration onsite where the sands and sandy gravels below the topsoil will perform adequately for storm water discharge into these granular sediments. Appropriate individual lot flow control Best Management Practices (BMPs) are required (Exhibit 17 -Surface Water). In the Technical Drainage Report (Exhibit 8, Section 4: Flow Control Review), BMPs are proposed as the engineer proposes to provide full infiltration on each individual lot using dry wells or infiltration trenches per the 2009 City of Renton Drainage Manual. The drainage engineer states that the proposal is to mitigate infiltration on all the lots using "Full Infiltration" of developed impervious surfaces (Exhibit 8, Section 4: Flow Control Review). Stormwater drainage plans for individual lots will be required prior to issuance of construction permits. The Surface Water System Development fee for 2015 is $1,350.00 per lot and fees are payable prior to issuance of construction permits. Water Service:The project is located in City of Renton service area (Exhibit 17 - Engineering Review-Water subsection). There is a 12-inch ductile iron water main in N 28tn St and a 12-inch water main in Park Ave N. The project is in the 320 water pressure zone. All new construction must have a fire hydrant capable of delivering a minimum of 1,000 gpm, and must be located within 300 feet of all structure.There are fire hydrants in the vicinity that may be counted towards the fire protection of this project, but is subject to verification for being within 300 feet of the nearest corner of all buildings. Existing hydrants counted as fire protection will be required to be retrofitted with a 5- � inch quick disconnect storz fitting if not already in place. A water main extension is required on site to serve Lots 5 through 8 as identified on the plans (Exhibit 11). System development fees for water are based on the size of the new , domestic water meter that will serve the new home on each new lot. Fees for%-inch or 1-inch water meter install are$3,090.00 per lot for 2015. Credit will be given for the domestic water serving the existing homes. Fees are payable prior to issuance of the construction permit. 2015 fees for a %-inch meter drop installed by the City are $400.00. Z015 fees for a 1-inch meter drop installed by the City are $460.00. Fees change year to year. � Sanitary Sewer Service: The project is provided sewer service by the City of Renton (Exhibit 17 - Sanitary Service). There is an 8-inch sewer main in N 28ih St and an 8-inch Short P/at Report LUA14-001272 City of Renton Department of Community&Fconomic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA24-001172;SNPL-A Report of March 31,2015 Page 21 of 24 12.Safe Routes to School: Students wouid attend Renton School District. A safe walking route would be provided to all schools. J. CONCLUS/ONS: 1. The subject site is designated Residential Single Family (RSF) in the Comprehensive Land Use Plan and complies with the goals, objectives, and policies established with this designation. 2. The subject site is zoned Residential 8 (R-8) and complies with the zoning and development standards established with this designation, provided the applicant complies with the Renton Municipal Code and conditions of approval. 3. The proposed use is anticipated to be compatible with existing and futu�e surrounding uses as permitted in the R-8 zoning classification, provided the applicant complies with the Renton Municipal Code and conditions of approval. 4. Staff does not anticipate any adverse impacts on surrounding properties and uses as long as the conditions of approval are complied with. � 5. The proposed 8-lot short plat complies with the subdivision regulations as established by Renton Municipal Code and state law provided all advisory notes and conditions are complied with. ' 6. The proposed Nantucket Short Plat complies with the street standards as established by Renton Municipal Code, provided the project complies with all advisory notes and conditions of approval contained herein. 7. Safe and efficient.access and circulation has been provided for all users. 8. There are adequate public services and facilities to accommodate the proposed short plat. 9. Safe routes to schools are anticipated to be available, provided the applicant complies with the Renton Municipal Code and conditions of approval. K. DECISION: The Nantucket Short Plat, File No. LUA14-001272; SHPL-A; is APPROVED and subject to the following conditions: 1. The applicant shall provide a Detailed Landscape Plan that complies with RMC 4-8-120D that includes but is not limited to: a. A 10-foot onsite landscape buffer for lots along public streets. b. Landscaping plan for the stormwater tract that includes screening of any visible portions of the vault above grade from the public realm. c. Replace the proposed Katsura trees in the planting strip along Park Ave N with a small mature size tree that i5 appropriate for placement under overhead power lines. _ The revised landscape plan shall be submitted to the Current Planning Project Manager for review and approval prior to construction permit issuance. 2. The stormwater vault proposed in Tract A shall be designed to be located underground and/or covered in soil. No part of the vault shall be permitted to protrude from the ground surface. If it is determined that such application is not feasible an alternative method could be proposed for approval by the Planning Division. All ground/soil located around and over the vault shall Short P/at Report LUA14-001172 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14-001272;SNPL-A Report of March 31, 2015 Page 22 of 24 be landscaped, excluding the pavement area for the private access easement. A revised vault and landscaping plan shall be submitted to the Current Planning Project Manager for review and approval prior to construction permit issuance. 3. The residence to be constructed on Lot 4 at the intersection of the private street and N 28`h St shall have its primary entry oriented to N 28th St, the public street, and not the new private street, where the primary e�try shall at minimum meet the standards of RMC 4-2-115 Residential Design and Open Space Standards. The building design shall be reviewed and approved at the time of building permit application for Lot 4 needs a note on the face of the short plat. 4. The homes to be constructed on Lots 1—4 shall meet the minimum standards for Windows and Doors, referenced in RMC 4-2-115, along the public street frontages and not the Private Street and/or access easements. The building design shall be reviewed and approved at the time of building permit application. 5. The applicant shall add a note to the face of the short plat stating that only Lot 1 is allowed to gain direct access onto a public street and that the remainder of the lots shall gain access from either a pri�ate street and/or an access easement and not a public street. The note shall be reviewed and approved by the Current Planning Project Manager prior to short plat recording. 6. The applicant shall add a note to the face of the short plat stated that Lots 2 and 3 shall provide rear-loaded garages, and Lot 4 shall provide a side-loaded garage. The garage design will be reviewed and approved at the time of building permit application. 7. A note shall be placed on the face of the short plat indicating that the private street and � private shared access easements are to be maintained by the private properties associated with the access easement. Alternatively,the applicant could create a home owners association to establish maintenance responsibility. Review of either the note on the short plat or the home owners association documents shall be reviewed and approved by the Current Planning Project Manager and City Attorney (if necessary) prior to short plat recording. 8. A note shall be placed on the face of the short plat indicating that maintenance of the landscaping in Tract A is the responsibility of the homeowners within the subdivision; or, the applicant could create a home owners association to establish maintenance responsibility. Review of either the note on the short plat or the home owners association documents shall be reviewed and approved by the Current Planning Project Manager and City Attorney (if necessary) prior to short plat recording. 9. Any proposal to convert the stormwater vault within Tract A to a stormwater detention pond shall be considered a Major Plat Amendment subject to the requirements outlined under RMC 4-7-080M.2. 10. The applicant shall work with the Public Works Department to provide new or enhanced striping with a brighter green striping color for two existing crosswalks, located on the south side of NE 30th St (on-and off-ramp travelways from the interstate), if the crosswalks are within the City of Renton jurisdiction. This shall be accomplished prior to short plat recording. � Short Plat Report LUA14-001272 City of Rentan Department of Communrty& Economic Development Administrative Shart Plat Report& Decisian NANTUCKFT SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 21 of 24 12. Safe Routes to School: Students would attend Renton School District. A safe walking route would be provided to all schools. !. CONCLUS10N5: 1. The subject site is designated Residential Single Family (RSF) in the Comprehensive Land Use Plan and complies with the goals, objectives, and policies established with this designation. 2. The subject site is zoned Residential 8 (R-8) and complies with the zoning and development standards established with this designation, provided the applicant complies with the Renton Municipal Code and conditions of approval. 3. The proposed use is anticipated to be compatible with existing and future surrounding uses as permitted in the R-8 zoning classification, provided the applicant complies with the Renton Municipal Code and conditions of approval. 4. Staff does not anticipate any adverse impacts on su�rounding properties and uses as long as the conditions of approval are complied with. 5. The proposed 8-lot short plat complies with the subdivision regulations as established by Renton Municipal Code and state law provided all advisory notes and conditions are complied with. 6. The proposed Nantucket Short Plat complies with the street standards as established by Renton Municipal Code, provided the project complies with all advisory notes and conditions of approval contained herein. 7. Safe and efficient access and circulation has been provided for all users. 8. There are adequate public services and facilities to accommodate the proposed short plat. 9. Safe routes to schools are anticipated to be available, provided the applicant complies with the Renton Municipal Code and conditions of approval. K. DFC15/0N: The Nantucket Short Plat, File No. LUA14-001272; SHPL-A; is APPROVED and subject to the following conditions: 1. The applicant shall provide a Detailed Landscape Plan that complies with RMC 4-8-120D that includes but is not limited to: a. A 10-foot onsite landscape buffer for lots along public streets. b. Landscaping plan for the stormwater tract that includes screening of any visible portions of the vault above grade from the public realm. c. Replace the proposed Katsura trees in the planting strip along Park Ave N with a small mature size tree that is appropriate for placement under overhead power lines. The revised landscape plan shall be submitted to the Current Planning Project Manager for review and approval prior to construction permit issuance. 2. The stormwater vault proposed in Tract A shatl be designed to be located underground and/or covered in soil. No part of the vault shall be permitted to protrude from the ground surface. If it is determined that such application is not feasible an alternative method could be proposed for approval by the Planning Division. All ground/soil located around and over the vault shall Short Plat Report LUA1 4-001 2 72 City of Renton Department of Community& Economrc Development Administrative Short Plot Report& Decision � NANTUCKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 23 of 24 DECISION ON LAND USE ACTION: I SIGNATURE: 3�3+ 20J� Jennifer T. Henning, P/anning Direc r Date Depariment of Communify& Economic Development TRANSM/TTED this 315f of March,2015 to the Contact/Applicant/Owner(sJ: ' Contact/Appliconi: Owner: �I Darrel!Offe;Offe Engineers NantucketAvenue,LLC 13932 SE 159`h P! 2812 257`h P!SE Renton, WA 98058 Sammomish, WA 98075 I TRANSMITTED this 31S`of Morch,2015 to the Pprty(ies)of Record: Glen 8rown, Kennydale Insurance Agency Kim 8richacek RogerFleming 1319 N 28`h St 6277 Cumbre Visia Way 1404 N 14`h St Renton, WA 98056 Co(orado Springs, CO 80924 Renion, WA 98056 Michael Gunn Jeanne-K Hughes Thelma Sutherlond 2417 Garden Ct N 1421 N 28`h St 1205 N 29`�St Renton, WA 98056 Renton, WA 98057 Renton, WA 98056 Rich Wogner 10801 Main St Ste 110 eellevue, WA 98004 TRANSMITTED this 315C of March, 2015 to the following: Chip Vincent, CED Administrator Steve Lee, Development Engineering Manager Craig Burnell, Building Official Vanesso Dolbee, Current Plonning Manoger Fire Morshol L. LAND USE ACTION APPEALS, REQUEST FOR RECONSIDERATION, & EXPlRAT/ON: The administrative land use decision will become final if the decision is not appealed within 14 days of the decision date. APPEAL:This administrative land use decision will become final if not appealed in writing to the Hearing Examiner on or before 5:00 PM on April 14, 2014. An appeal of the decision(s) must be filed within the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-1i-680). Renton Municipal Code Section 4-8-110.B governs appeals to the Hearing Examiner. Appeals must be filed in writing together � with the required fee to the Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057. Additional information regarding the appeal process may be obtained from the City Clerk's Office, Renton City Hall - 7th Floor, (425) 430-6510. EXPIRATION: The administrative short plat decision will expire two (2) years from the date of decision. A single one (1) year extension may be requested pursuant to RMC 4-7-070.M. Short Plot Report LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUtKET SHORT PLAT LUA14-001272;SHPL-A Report of March 31, 2015 Page 24 of 24 RECONSIDERATION: Within 14 days of the decision date, any party may request that the decision be reopened by the approval body. The approval body may modify his decision if material evidence not readily discoverable prior to the original decision is found or if he finds there was misrepresentation of fact. After review of the reconsideration request, if the approval body finds sufficient evidence to amend the original decision, there will be no further extension of the appeal period. Any person wishing to take further action must file a formal appeal within the 14-day appeal time frame. THE APPEARANCE OF FAIRNESS DOCTRINE: provides that no ex parte (private one-on-one) communications may occur concerning the land use decision. The Doctrine applies not only to the initial decision, but to Appeals to the Hearing Examiner as well. All communications after the decision/approval date must be made in writingthrough the Hearing Examiner. All communications are public record and this permits all interested parties to know the contents of the communication and would allow them to openly rebut the evidence in writing. Any violation of this doctrine could result in the invalidation of the appeal by the Court. � Short Plat Report LUA14-001272 City of Renton Department of Community& Economic Development Administrative Short Plat Report& Decision NANTUCKET SHORT PLAT LUA14001172;SHPL-A Report of March 31, 2015 Page 23 of 24 DECISION ON LAND USE ACTION: SIGNATURE: 3�31 2a1 S' Jennifer T. Henning, Planninq Direc r Date Department of Community& Economic Development TRANSMITTED this 315`of March,2015 to the Contoct/Applicant/Owner(sJ: Contact/Applicant: Owner: Darre/l Offe;Offe Engineers NantucketAvenue,LLC 13932 SE 159`h PI 2811257`h PJ SE Renton, WA 98058 Sammamish, WA 98075 TRANSMITTED this 3151 of March,2015 to the Porty(iesJ of Recard: Glen Brown, Kennydale lnsurance Agency Kim Srichacek Roger Fleming 1319 N 28`h St 6277 Cumbre Vista Way 1404 N 24`h St Renton, WA 98056 Colorado Springs, CO 80924 Renton, WA 98056 Michae!Gunn leanne-K Hughes Thelma Sutherland 2417 Garden Ct N 3421 N 28"'St 1205 N 29`�St Renton, WA 98056 Renton, WA 98057 Renton, WA 98056 Rrch Wagner 10801 Main St Ste I10 Bellevue, WA 98004 TRANSMITTED this 315L of March, 2015 to the following: Chip Vincent, CEDAdministrator Steve Lee, Development Engineering Manager Craig Burnell, Burlding Official Vanessa Dolbee, Current P/anning Manoger Fire Marsha! L. LAl1lD USE ACTION APPEALS, REQUEST FOR RECONS/DERAT/ON, & EXP/RATION: The administrative land use decision will become final if the decision is not appealed within 14 days of the decision date. APPEAL:This administrative land use decision will become final if not appealed in writing to the Hearing Examiner on or before 5:00 PM on April 14, 2014. An appeal of the decision(s) must be filed within the 14-day appeal period (RCW 43.21.C.075(3); WAC 197-11-680). Renton Municipa) Code Section 4-8-110.6 governs appeals to the Hearing Examiner. Appeals must be filed in writing together with the required fee to the Hearing Examiner, City of Renton, 1055 South Grady Way, Renton, WA 98057. Additional information regarding the appeal process may be obtained from the City Clerk's Office, Renton City Hall - 7th Floor, (425) 430-6510. EXPIRATION: The administrative short plat decision will expire two (2) years from the date of decision. A single one (1) year extension may be requested pursuant to RMC 4-7-070.M. Short P/at Report LUA14-001272 (. _.,' . .��) � � %� � Section 7: Other Permits , None applicable at this time ; '.� � � �� , � ; � , � � .-, � ,. � � �. � �, , � r��, , ; � ; ; �,_��, � �, • , Section 8: CSWPPP Analysis and Design The proposed development consists of 1.44 acres of property. The proposal is to minimize the amount of i area needed to install the required improvements. The project proposal is to clear and grade up to 0.88 I acres as to allow for minimal disturbance as part of tis utility permit. A NPDES permit will be required from the State Department of Ecology if the owner intends to clear and disturb greater than one acre. The retention of the existing vegetation during construction shoufd reduce the amount of construction runoff in � the wet seasons. An erosion control plan has been provided as part of the ci�il construction plans submitted to the City of Renton for the utility permit. i �._: '� �� ._ , � r, Section 9: Bond Quantities, Facility Summaries, and Declaration of Covenant i A Declaration of Covenant(Operation, maintenance, and restrictions) will be provided at the final civil engineering construction plans submittal to the City. Bond Quantity forms will be provided at time of initial Utility Permit review by the City of Renton. �� r� r� � � Site Improvement Bond Quantity Worksheet S15 Webdate: 04/03/2015 � King County Department of Permitting & Environmental Review 35030 SE Douglas Street, Suite 210 Snoqualmie, Washington 98065-9266 For alternate formats, call 206-296-6600. 206-296-6600 TTY Relay 711 Project Name: � '��.0`t�t Date: .�(,I��Z, �� Location: '�� }� �;�� ("�2-�"� Project No.: �� 1� �—� � 2.7Z Activity No.: �l'j� ��(rje7-� Note: All prices include labor, equipment, materials, overhead and Clearing greater than or equal to 5,000 board feet of timber? profit. Prices are from RS Means data adjusted for the Seattle area or from local sources if not included in the RS Means database. yes no If yes, Forest Practice Permit Number: (RCW 76.09) Page 1 of 9 Unit prices updated: 3/2/2015 Version: 3/2/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1s Report Date: 6/2/2015 � , _� - _ _ . S15 Web date: 04/03/2015 Site Improvement Bond Quantity Worksheet Unit #of Reference# Price Unit Quantit Applications Cost EROSION/SEDIMENT CONTROL Number Backfill &compaction-embankment ESC-1 $ 6.00 CY � '� � ��•'— Check dams, 4" minus rock ESC-2 SWDM 5.4.6.3 $ 80.00 Each Crushed surfacing 1 1/4"minus ESC-3 WSDOT 9-03.9(3) $ 95.00 CY Ditching ESC-4 $ 9.00 CY Excavation-bulk ESC-5 $ 2.00 CY "� Fence, silt ESC-6 SWDM 5.4.3.1 $ 1.50 LF ' !� Fence,Temporary(NGPE) ESC-7 $ 1.50 LF Hydroseeding ESC-8 SWDM 5.4.2.4 $ 0.80 SY Jute Mesh ESC-9 SWDM 5.4.2.2 $ 3.50 SY Mulch, by hand, straw, 3"deep ESC-10 SWDM 5.4.2.1 $ 2.50 SY Mulch, by machine, straw, 2"deep ESC-11 SWDM 5.4.2.1 $ 2.00 SY Piping, tempora , CPP, 6" ESC-12 $ 12.00 LF '� Pi in , temporary, CPP, 8" ESC-13 $ 14.00 LF Pipin ,temporary, CPP, 12" ESC-14 $ 18.00 LF Plastic covering, 6mm thick, sandbagged ESC-15 SWDM 5.4.2.3 $ 4,00 SY Rip Rap, machine laced; slo es ESC-16 WSDOT 9-13.1 2 $ 45.00 CY Rock Construction Entrance, 50'x15'x1' ESC-17 SWDM 5.4.4.1 $ 1,800.00 Each �r Rock Construction Entrance, 100'x15'x1' ESC-18 SWDM 5.4.4.1 $ 3,200.00 Each Sediment pond riser assembly ESC-19 SWDM 5.4.5.2 $ 2,200.00 Each '� Sediment tra , 5' hi h berm ESC-20 SWDM 5.4.5.1 $ 19.00 LF Sed.trap,5'high, riprapped spillway berm section ESC-21 SWDM 5.4.5.1 $ 70.00 LF Seeding, by hand ESC-22 SWDM 5.4.2.4 $ 1.00 SY Sodding, 1"deep, level ground ESC-23 SWDM 5.4.2.5 $ 8.00 SY Soddin , 1"dee , sloped ground ESC-24 SWDM 5.4.2.5 $ 10.00 SY TESC Supervisor ESG25 $ 110.00 HR � � Water truck, dust control ESC-26 SWDM 5.4.7 $ 140.00 HR '' WRITE-IN-ITEMS "`*** (see page 9) - Each � S ' ESC SUBTOTAL: $ !/� '-r 30%CONTINGENCY&MOBILIZATION: $ [� = ' ESC TOTAL: $ - COLUMN: � � A Page 2 of 9 ��) ��j� �� U it prices updated: 3/2/2015 Version: 3/2/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1s Report Date: 6/2/2015 � --�L.....�. _..C_,�..1., 5ite �mprovement t�ona c�uantity vvorksf�eet Existing Future Public Private Right-of-Way Right of Way Improvements &Draina e Facilities Unit Price Unit Quant. Cost Quant. Cost Quant. Cost GENERALITEMS No. Backfill&Compaction-embankment GI-1 $ 6.00 CY Backfill&Com action-trench GI-2 $ 9.00 CY Clear/Remove Brush,b hand GI-3 $ 1.00 SY Clearin /Grubbin /Tree Removal GI-4 $10,000.00 Acre 0.1 1,000.00 0.1 1,000.00 0.6 6,000.00 Excavation-bulk GI-5 $ 2.00 CY Excavation-Trench GI-6 $ 5.00 CY Fencin ,cedar,6'high GI-7 $ 20.00 LF 290 5,800.00 Fencin ,chain link,vin I coated, 6'hi h GI-8 $ 20.00 LF Fencin ,chain link, ate,vin I coated, 20 GI-9 $ 1,400.00 Each Fencin ,s lit rail,3'hi h GI-10 $ 15.00 LF Fill&com act-common barrow GI-11 $ 25.00 CY Fill&com act- ravel base GI-12 $ 27.00 CY Fill 8 com act-screened to soil GI-13 $ 39.00 CY Gabion, 12"deep,stone filled mesh GI-14 $ 65.00 SY Gabion, 18"dee ,stone filled mesh GI-15 $ 90.00 SY Gabion,36"deep,stone filled mesh GI-16 $ 150.00 SY Gradin ,fine,b hand GI-17 $ 2.50 SY Gradin ,fine,with rader GI-18 $ 2.00 SY 780 1,560.00 Monuments,3'lon GI-19 $ 250.00 Each Sensitive Areas Si n GI-20 $ 7.00 Each Soddin , 1"deep,sloped round GI-21 $ 8.00 SY Surve in ,line& rade GI-22 $ 850.00 Da 2 1,700.00 2 1,700.00 6 5,100.00 Surve ing,lot location/lines GI-23 $ 1,800.00 Acre 1 1,800.00 Traffic control crew(2 fla ers) GI-24 $ 120.00 HR 16 1,920.00 4 480.00 Trail,4"chi ed wood GI-25 $ 8.00 SY Trail,4"crushed cinder GI-26 $ 9.00 SY Trail,4"top course GI-27 $ 12.00 SY Wall,retainin ,concrete GI-28 $ 55.00 SF Wall,rockery GI-29 $ 15.00 SF Page 3 of 9 SUBTOTAL 4,620.00 3,180.00 20,260.00 Unit prices updated: 03/02/2015 "KCC 27A authorizes only one bond reduction. Vefsion: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1sx Report Date: 6/2/2015 � vvduuat2. �vi�ait�lo �ite Improvement �ond Quantity Worksheet Existing Future Public Private Right-of-way Right of Way Improvements 8 Drainage Facilities Unit Price Unit Quant. Cost Quant. Cost Quant. Cost ROADIMPROVEMENT No. AC Grindin ,4'wide machine< 1000s RI-1 $ 30.00 SY 910 27,300.00 AC Grindin ,4'wide machine 1000-2000 RI-2 $ 16.00 SY AC Grindin ,4'wide machine>2000s RI-3 $ 10.00 SY AC Removal/Dis osal RI-4 $ 35.00 SY Barricade, e III Permanent RI-6 $ 56.00 LF Curb&Gutter,rolled RI-7 $ 17.00 LF Curb&Gutter,vertical RI-8 $ 12.50 LF 448 5,600.00 292 3,650.00 Curb and Gutter,demolition and dis osal RI-9 $ 18.00 LF Curb,extruded as halt RI-10 $ 5.50 LF Curb,extruded concrete RI-11 $ 7.00 LF Sawcut,asphalt,3"de th RI-12 $ 1.85 LF 510 943.50 Sawcut,concrete,per 1"de th RI-13 $ 3.00 LF Sealant,as halt RI-14 $ 2.00 LF 510 1,020.00 Shoulder,AC, see AC road unit rice) RI-15 $ - SY Shoulder, ravel,4"thick RI-16 $ 15.00 SY Sidewalk,4"thick RI-17 $ 38.00 SY 396 15,048.00 Sidewalk,4"thick,demolition and dis os RI-18 $ 32.00 SY Sidewalk,5"thick RI-19 $ 41.00 SY 52 2,132.00 Sidewalk,5"thick,demolition and dis os RI-20 $ 40.00 SY Si n,handica RI-21 $ 85.00 Each Stri in , er stall RI-22 $ 7.00 Each Stri in ,thermo lastic,(for crosswalk RI-23 $ 3.00 SF Striping,4"reflectorized line RI-24 $ 0.50 LF Page 4 of 9 SUBTOTAL 29,263.50 22,780.00 3,650.00 Unit prices updated: 03/02/2015 "KCC 27A authorizes only one bond reduction. Version: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1sx Report Date: 6/2/2015 - .��, i', ,-�. � - .� - .�-� .- '". . - .-. . '. ._, „ ._. -� .�--. ,., .- ._. ,-_. "�.. ;-_. ,-•, ,,-' ,. , ,_ --, ,. . • � '.��,. ,, ' ;i-.� .---. . . . . . .� . . .� . . . � . . . . . , . . . . . . . , . .� . . .. . �ite Improvement �ond (�uantity Worksheet j�VU`� '`J„v'° Existing Future Public Private Right-of-way Right of Way Improvements &Draina e Facilities Unit Price Unit Quant. Cost Quant. Cost Quant. Cost ROAD SURFACING No. 4"Rock=2.5 base& 1.5"to course 9 1/2"Rock=8"base& 1.5"to course Additional 2,5"Crushed Surfacin RS-1 $ 3.60 SY HMA 1/2"Overla , 1.5" RS-2 $ 14.00 SY HMA 1/2"Overla 2" RS-3 $ 18,00 SY HMA Road,2",4"rock,First 2500 SY RS-4 $ 28.00 SY 165 4,620.00 760 21,280.00 HMA Road,2",4"rock,Qt .over 2500 S RS-5 $ 21.00 SY HMA Road,3",9 1/2"Rock, First 2500 S RS-6 $ 35.00 SY HMA Road,3",9 1/2"Rock,Qt Over 25 RS-7 $ 42.00 SY Not Used RS-8 Not Used RS-9 HMA Road,6"De th,First 2500 SY RS-10 $ 33.10 SY HMA Road,6"Depth,Qt .Over 2500 SY RS-11 $ 30.00 SY HMA 3/4"or 1",4"De th RS-12 $ 20.00 SY Gravel Road,4"rock,First 2500 SY RS-13 $ 15.00 SY Gravel Road,4"rock,Q .over 2500 SY RS-14 $ 10.00 SY PCC Road Add Under Write-Ins w/Desi RS-15 Thickened Edge RS-17 $ 8.60 LF Page 5 of 9 SUBTOTAL 4,620.00 21,280.00 Unit prices updated: 03/02/2015 'KCC 27A authorizes only one bond reduction. VefSio►1: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1sx Report Date:6/2/2015 � vvZ��o�E. vv/�oicJ'ia . �ite Improvement �3ond Quantity Worksheet Existing Future Public Private Right-of-way Right of Way Improvements &Draina e Facilities Unit Price Unit Quant. Cost Quant. Cost Quant. Cost DRAINAGE (CPP=Corrugated Plastic Pipe,N12 or Equivalent) For Culvert rices, Avera e of 4'cover was assumed.Assume erforated PVC is same rice as solid i e. Access Road,R/D D-1 $ 21.00 SY Bollards-fixed D-2 $ 240,74 Each Bollards-removable D-3 $ 452.34 Each " CBs include frame and lid) CB Type I D-4 $ 1,500.00 Each 3 4,500.00 7 10,500.00 2 3,000.00 CB T e IL D-5 $ 1,750.00 Each 1 1,750.00 CB T pe II,48"diameter D-6 $ 2,300.00 Each 1 2,300.00 for additional de th over 4' D-7 $ 480.00 FT 2 960.00 CB T pe II,54"diameter D-8 $ 2,500.00 Each for additional de th over 4' D-9 $ 495.00 FT CB T e II,60"diameter D-10 $ 2,800.00 Each for additional depth over 4' D-11 $ 600.00 FT CB Type Ii,72"diameter D-12 $ 3,600.00 Each for additional depth over 4' D-13 $ 850.00 FT Throu h-curb Inlet Framework Add D-14 $ 400.00 Each 1 400.00 Cleanout,PVC,4" D-15 $ 150.00 Each Cleanout,PVC,6" D-16 $ 170.00 Each Cleanout,PVC,S" D-17 $ 200.00 Each Culvert,PVC,4" D-18 $ 10.00 LF Culvert,PVC,6" D-19 $ 13.00 LF Culvert,PVC, 8" D-20 $ 15.00 LF Culvert,PVC, 12" D-21 $ 23.00 LF Culvert,CMP,8" D-22 $ 19.00 LF Culvert,CMP, 12" D-23 $ 29.00 LF Culvert,CMP, 15" D-24 $ 35.00 LF Culvert,CMP, 18" D-25 $ 41.00 LF Culvert,CMP,24" D-26 $ 56.00 LF Cuivert,CMP,30" D-27 $ 78.00 LF Culvert,CMP,36" D-28 $ 130.00 LF Culvert,CMP,48" D-29 $ 190.00 LF Culvert,CMP,60" D-30 $ 270.00 LF Culvert,CMP,72" D-31 $ 350.00 LF Page 6 of 9 SUBTOTAL 6,650.00 13,760.00 3,000.00 I Unit prices updated: 03/02/2015 "KCC 27A authorizes only one bond reduction. Vefslon: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.xisx Report Date: 6/2/2015 �. _ � � �� i � ;�- � .� � � � � � , � - -, -.; - - � � � Site Improve�ment� �ond Quantity Worksheet � ""�°°�`�: ��`°"`�'°� - Existing Future Public Private Right-of-way Right of Way Improvements DRAINAGE CONTINUED &Drainage Facilities No. Unit Price Unit Quant. Cost Quant. Cost Quant. Cost Culvert,Concrete,8" D-32 $ 25.00 LF Culvert,Concrete, 12" D-33 $ 36.00 LF 204 7344 Culvert,Cancrete, 15" D-34 $ 42.00 LF Culvert,Concrete, 18" D-35 $ 48.00 LF Culvert,Concrete,24" D-36 $ 78.00 LF Culvert,Concrete,30" D-37 $ 125.00 LF Culvert,Concrete,36" D-38 $ 150.00 LF Culvert,Concrete,42" D-39 $ 175.00 LF Culvert,Concrete,48" D-40 $ 205.00 LF Culvert,CPP,6" D-41 $ 14.00 LF Culvert,CPP,8" D-42 $ 16.00 LF Culvert,CPP, 12" D-43 $ 24.00 LF 506 12144 162 3888 Culvert,CPP, 15" D-44 $ 35.00 LF Culvert,CPP, 18" D-45 $ 41.00 LF Culvert,CPP,24" D-46 $ 56.00 LF Culvert,CPP,30" D-47 $ 78.00 LF Culvert,CPP,36" D-48 $ 130.00 LF Ditchin D-49 $ 9.50 CY Flow Dis ersal Trench 1,436 base+) D-50 $ 28.00 LF French Drain (3'depth) D-51 $ 26.00 LF Geotextile,laid in trench,polyprop lene D-52 $ 3.00 SY Mid-tank Access Riser,48"dia, 6'deep D-54 $ 2,000.00 Each Pond Overflow S illwa D-55 $ 16.00 SY Restrictor/Oil Separator, 12" D-56 $ 1,150.00 Each Restrictor/Oil Se arator, 15" D-57 $ 1,350.00 Each Restrictor/Oil Separator, 18" D-58 $ 1,700,00 Each Riprap, laced D-59 $ 42.00 CY Tank End Reducer(36"diameter) D-60 $ 1,200.00 Each Trash Rack, 12" D-61 $ 350.00 Each Trash Rack, 15" D-62 $ 410.00 Each Trash Rack, 18" D-63 $ 480.00 Each Trash Rack,21" D-64 $ 550.00 Each Page 7 of 9 SUBTOTAL 19488 3888 Unit prices updated: 03/02/2015 'KCC 27A authorizes only one bond reduction. VerSIOn: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1sx Report Date:6/2/2015 • vvdLuaiB. �YiGoi��10 �ite Improvement �ond c�uantity Worksheet Existing Future Public Private Right-of-way Rlght of Way Improvements 8 Draina e Facilities Unit Price Unit Quant. Price Quant. Cost Quant. Cost PARKING LOT SURFACING Not To Be Used For Roads Or Shoulders No. 2"AC,2"top course rock&4"borrow PL-1 $ 21.00 SY NA NA 2"AC, 1.5" to course&2.5"base cours PL-2 $ 28.00 SY NA NA 4"select borrow PL-3 $ 5.00 SY NA NA 1.5"top course rock&2.5"base course PL-4 $ 14.00 SY NA NA UTILITY POLES 8�STREET LIGHTING Utilit ole relocation costs must be accom anied b Franchlse Utlllt 's Cost Estimate Utility Pole(s)Relocation UP-1 Lum Sum Street Li ht Poles w/Luminaires UP-2 $ 4,500.00 Each 6 27,000.00 WRITE-IN-ITEMS (Such as detention/water ualit vaults. No. Water Qualit Vault WI-1 $50,000.00 Each 1 50,000.00 Sewer Improvements WI-2 $33,295.00 Each 1 33,295.00 Water Improvements WI-3 $31,702.00 Each 1 31,702.00 Outfall pad WI-4 $ 800.00 Each 1 800.00 WI-5 FT WI-6 WI-7 WI-8 WI-9 wl-10 SUBTOTAL 142,797.00 SUBTOTAL(SUM ALL PAGES): 40,533.50 206,625.00 52,078.00 30%CONTINGENCY&MOBILIZATION: 12,160.05 61,987.50 15,623.40 GRANDTOTAL: 52,693.55 268,612.50 67,701.40 COLUMN: B C D Page 8 of 9 Unit prices updated: 03/02/2015 'KCC 27A authorizes only one bond reduction. VefSion: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1sx Report Date:6/2/2015 Nantucket 8 Lot Project 6/Z/1015 � On Site Improvements Estimated uanti Units Price Total Sanitary Sewer 48"-8'deep MH 1 each $2,500 $2,500 54"-13'deep cut-in MH (to exist.) 1 each $6,0�0 $6,000 8"-4' inside drop connection 1 each $1,000 $1,000 8"sanitary sewer(pvc) 275 lin.ft. $38 $10,450 6" side sewer(pvc) 171 lin.ft. $3fi $6,156 connect side sewer to ex. Sewer main 2 each $750 $1,500 Air test and N 1 lump sum $2,800 $2,800 WSST(9.5%) $2,889 .$33,295 Water System Connect to ex. WM w/8"cut in valves&parts 1 each $2,200 $2,200 8" D.I. 306 lin. ft. $42 $12,852 2" perm. blow off 1 each $1,500 $1,500 8"gate valve 1 each $650 $650 Fire Hydrants w/foot valve 1 each $4,800 $4,800 service line off ex. W.M. 2 each $700 $1,400 1"service line 5 each $700 $3,500 Pressure testing and inspections 1 each $1,800 $1,800 relocate ex. Service 1 each $250 $250 WSST(9.5%) $2,750 $31,701 i __ _ __ _ __ _ ,� __ __ - _ - - - - - - _ __ _ __ _ _ _ �. � �� , , . - �� , � . . � , . ; � � . . . � _ � _ _ � � � � � Web date: 04/0312 1� _ _ ��, Site improvement Bond Quantity Worksheet ° � Original bond computations prepared by: Name: Darrell L. Offe, Jr. oate: June 2,2015 PE Reglstration Number: #27460 Tel.#: 425-260-3412 Firm Name: Offe Engineers, PLLC Aaaress: 13932 SE 159th Place, Renton ,WA 98058 Project No: FINANCIAL GUARANTEE REQUIREMENTS PERFORMANCE BOND* MINIMUM BOND"AMOUNT PUBLIC ROAD&DRAINAGE AMOUNT REQUIRED FOR RECORDING OR MAINTENANCE/DEFECT BOND" TEMPORARY OCCUPANCY AT Stabilization/Erosion Sediment Control (ESC) (A) $ �'2,�'^''f l � - SUBSTANTIAL COMPLETION*" Existing Right-of-Way Improvements (B) $ 52,693.6 Future Public Right of Way& Drainage Facilities (C) $ 268,612.5 Private Improvements (D) $ 67,701.4 Calculated Quantity Completed � Total Right-of Way and/or Site Restoration Bond"/'"' (A+B) $ �,��j -�89�:9� (First$7,500 of bond*shall be cash.) � � `` l� �2 Performance Bond"Amount (A+B+C+D) = TOTAL (T) � �8 T x 0.30 $ � $+F�7�'g.2 Minimum i $2000. Minimum is$2000. (B+C)X Maintenance/Defect Bond'Total 0.25= $ 80,326.5 Minimum is$2000. NAME OF PERSON PREPARING BOND"REDUCTION: Date: *NOTE: The word"bond"as used in this document means a financial guarantee acceptable to King County. **NOTE: KCC 27A authorizes right of way and site restoration bonds to be combined when both are required. The restoration requirement shall include the total cost for all TESC as a minimum, not a maximum. In addition,corrective work, both on-and off-site needs to be included. Quantities shall reflect worse case scenarios not just minimum requirements. For example, if a salmonid stream may be damaged, some estimated costs for restoration needs to be reflected in this amount. The 30%contingency and mobilization costs are computed in this quantity. ' *""NOTE: Per KCC 27A,total bond amounts remaining after reduction shall not be less than 30%of the original amount(T)or as revised by major design changes. REQUIRED BOND*AMOUNTS ARE SUBJECT TO REVIEW AND MODIFICATION BY KING COUNTY Page 9 of 9 Unit prices updated: 03/02/2015 Check out the DDES Web site af www.kinpcountv.qov/permits Version: 03/02/2015 Copy of Copy of Site Improvement Bond Quantity Worksheet 2015.x1sx Report Date: 6/2/2015 �I I I. r RECORDING REQUESTED BY AND WHEN RECORDED MAIL TO: CITY CLERK'S OFFICE CITY OF RENTON 1055 SOUTH GRADY WAY RENTON, WA 98057 DECLARATION OF COVENANT I' FOR MAINTENANCE AND INSPECTION OF FLOW CONTROL BMPS Grantor: �. Grantee: City of Renton Legal Description: I Additional Legal(s)on: Assessor's T�Parcel ID#: IN CONSIDERATION of the approved City of Renton(check one of the following) ❑ residential building permit, ❑ commercial building permit, ❑ clearing and grading permit, ❑ subdivision permit, or • ❑ short subdivision permit for Application File No.LUA/SWP relating to the real property("Property")described above,the Grantor(s),the owner(s)in fee of that Property,hereby covenants(covenant)with City or Renton, a political subdivision of the state of Washington,that he/she(they)will observe,consent to,and abide by the conditions and obligations set forth and described in Paragraphs 1 through 8 below with regard to the Property. Grantor(s)hereby grants(grant), covenants(covenant), and agrees(agree)as follows: 1. Grantor(s)or his/her(their}successors in interest and assigns("Owners")shall retain,uphold, and protect the stormwater management devices,features,pathways,limits, and restrictions,known as flow control best management practices("BMPs"),shown on the approved Flow Control BMP Site Plan � for the Property attached hereto and incorporated herem as Exhibit A. 2. The Owners shall at their own cost,operate,maintain,and keep in good repair,the Property's BMPs as described in the approved Design and Maintenance Details for each BMP attached hereto and incorporated herein as E�ibit B. 3. City or Renton shall provide at least 30 days written notice to the Owners that entry on the I Property is planned for the inspection of the BMPs. After the 30 days,the Owners shall allow the City of Renton to enter for the sole purpose of inspecting the BMPs. In lieu of inspection by the City,the Owners may elect to engage a licensed civil engineer registered in the state of VJashington who has expertise in drainage to inspect the BMPs and provide a written report describing their condition. If the engineer option is chosen,the Owners shall provide written notice to the City of Renton within fifteen days of receiving the City's notice of inspection. Within 30 days of giving this notice,the Owners,or the engineer on behalf of the Owners,shall provide the engineer's report to the City of Renton. If the report is not provided in a timely manner as specified above,the City of Renton may inspect the BMPs without further notice. 4. If the City determines from its inspection, or from an engineer's report provided in accordance with Paragraph 3,that maintenance,repair,restoration, and/or mitigation work is required for the BMPs, The City shall notify the Owners of the specific maintenance,repair, restoration,and/or mitigation work • (Work)required under RMC 4-6-030. The City shall also set a reasonable deadline for completing the Work or providing an engineer's report that verifies completion of the Work. After the deadline has passed, the Owners shall a11ow the City access to re-inspect the BMPs unless an engineer's report has been provided verifying completion of the Work. If the wark is not completed properly within the time frame set by the City,the City may initiate an enforcement action. Failure to properly maintain the BMPs is a violation of RMC 4-b-030 and may subject the Owners to enforcement under the RMC 1-3, including fines and penalties. _ 5. Apart from perfornung routine landscape maintenance,the Owners are hereby required to obtain written approval from the City or Renton before performing any alterations or modifications to the BMPs. 6. Any notice or approval required to be given by one party to the other under the provisions of this Declaration of Covenant shall be effective upon personal delivery to the other party, or after three(3) days from the date that the notice or approval is mailed with delivery confirmation to the current address , on record with each Party. The parties shall notify each other of any change to their addresses. 7. This Declaration of Covenant is intended to promote the efficient and effective management of surface water drainage on the Property,and it shall inure to the benefit of a11 the citizens of the City of Renton and its successors and assigns. This Declaration of Covenant shall run with the land and be binding upon Grantor(s),and Grantor's(s')successors in interest and assigns. 8. This Declaration of Covenant may be terminated by execution of a written agreement by the Owners and the City of Renton that is recorded by King County in its real property records. � � � �� IN WITNESS WHEREOF,this Declaration of Covenant for the Maintenance and Inspection of Flow Control BMPs is executed this day of ,20 , ( GRANTOR, owner of the Property � i ( GRANTOR, owner of the Property � STATE OF WASHINGTON ) COUNTY OF KING )ss. On this day personally appeared before me: ,to me known to be the individual(s)described in and who executed the within and foregoing instrument and acknowledged that they signed the same as their free and voluntary act and deed,for the uses and purposes therein stated. Given under my hand and official seal this day of ,2p I� � ' ( ' Printed name ' � Notary Public in and for the State of Washington, � residing at � My appointment expires l�� E • I � � � ' l Section 10: Operation and Maintenance Manual `, The Operation and Maintenance of the proposed BMP's provided will be included within the Declaration of Covenant from Section 9. These documents will be provided for review on as part of the utility permit submittal. ! ,_ . �� . � � ,_ _ �, � � � � r f�� ; I �� , � �� _ ; sEcrioN c.2 Fr,ow corr�oL B�s ( 3. The depression overflow point must be at least 6 inches below any adjacent pavement area and must be situated so that overflow dces not cause erosion damage or unplanned inundation. 4. T'he depression side slopes must be no steeper than 3 horizontal to 1 vertical. � ,. 5. Spacing between multiple infiltration depressions shall be a minimum of 4 feet. 6. Infiltration depressions must be setback at least 15 feet from buildings with crawl space or basement elevations that are below the overflow point of the infiltxation depression. ' 7. Infiltration depressions may be any size or shape provided the above specifications and the minimum requirements in Section C.2.2.1 are met. � S. The ground surface of the infiltration depression must be vegetated with grass or other dense ground cover. i C.2.2.6 MAINTENANCE INSTRUCTIONS FOR FULL INFILTRATION Ifthe full infiltration flow control BMP is proposed for a project,the following maintenance and operation ( instructions must be recorded as an attaclunent to the required declaration of covenant and grant of � easement per Requirement 3 of Section C.1.3.3(p.G 18). T'he intent of these instructions is to explain to future property owners,the purpose of the BMP and how it must be maintained and operated. These t� instructions are intended to be a minunum;DDES may require additional instructions based on site- i�" specific conditions. Also,as the County gains more experience with the maintenance and operation of these BMPs,future updates to the instructions will be posted on King County's Surface Water Design ', . Manual website. r� ❑ TEXT OF INSTRUCTIONS Your property contains a stormwater management flow control BMP(best management practice)called "full infiftration,"which was installed to mitigate the stormwater quantity and qualiry impacts of some or all of the impervious surfaces on yaur property. Full infiltration is a method of soaking runoff from impervious area(such as paved areas and roofs)into the ground. If properly installed and maintained,full infiltration can manage runoff so that a majority of precipitation events are absorbed. Infiltration devices, such as gravel filled trenches,drywells,and ground surface depressions,facilitate this process by putting runoff in direct contact with the soil and holding the runoff long enough to soak most of it into the ground. To be �� successful,the soil condition around the infiltration device must be reliably able to soak water irrto the � ground for a reasonable number of years. ( The infiltration devices used on your property include the following as indicated on the flow control BMP site plan: 0 gravel filled trenches, ❑ drywells, ❑ground surface depressions. The size, placement,and composition of these devices as depicted by the flow oontrol BMP site plan and design details must be maintained and may not be changed without written approval either from the King County Water and Land , Resources Division or through a future development permit from IGng County. Infiltration devices must be inspected annually and after major storm events to identify and repair any physical defects. Maintenance and operation of the system should focus on ensuring the system's�iability by preventing sediment-laden flows from entering the device. Excessive sedimentation will result in a ; plugged or non-functioning facility. If the infiltration device has a catch basin,sediment accumulation must be removed on a yearly basis or more frequently if necessary. Prolonged ponding around or atop a device may indicate a plugged facility. If the device bec:omes plugged, it must be replaced. Keeping the areas that drain to infiltration devices well swept and Gean will enhance the longevity of these devices. For roofs, frequent Geaning of gutters will reduce sediment loads to these devices. � `�_�� I 1/9/2009 2009 Surface Water Design Manual—Appendix C C-44 c.z.2 Fu�.�a.��ov FIGURE G2.2.0 TYPICAL DRYWELL IlV�'ILTRATION SYSTEM Roof Downspout House Catch Basin �—(Yard Drain) / `---Roof f��W Downspout � DRY WELL 481nch Diameter Hole Filled with PLAN VIEW 1��2-3nWashed Drain Rock IdTS Roof Downspout Mark Center of Hole with 1"Capped PVC House �Overflow or Other means Splash Block Topsoil Flush with Surface - I + - - - - - - - 1' min. fl�W ` -' �°� �`�Do�o��Dn � � �� Fine Mesh Screen LI Min_4"dia. �o ��•��p�p PVC Pipe �ao��° °�°�Q� Catch Basin ��' '�p (Yard Drain) � � �� 48 Inch Diameter � Vaies Sides of Hole �� Hole Filled with � Lined with �� 11�2-3"Washed � Ffter Fabric �•� Drain Rock � 15'min. ��op��o�p�o� o � o�� Min. 1'above Seasonal DRY WELL High Groundwater Table ' SECTION � ' NTS � � ' 2009 Surface Wa[er Design Manual-Appendix C 1/9/2009 C-47 APPENDIX A MAINTENANCE REQUIREIV�NTS FOR F[,OW CONTROL,CONVEYANCE,AND WQ FACILIT'IES ,� NO. 5-CATCH BASINS AND MANHOLES MaiMonanw Defect w Problem Conditlon When Msintananu is Needed Results Expacted When Component AAa(Monanca is Perfwrt►ed Structure Sediment Sediment exceeds 60%of the depth from the Sump of catch basin contains no botlom of the catch basin to the invert of the sediment. lowest pipe into or out of the qtch basin or is within 6 inches of the invert of the lowest pipe into or oul of the catch basin. Trash and debris Trash or debris of mare than'r4 cubic foot which No Trash or debris blocking or is located immediately in fi�ont of the catch basin potentially blodcing entrance to opening or is blocking capaaty of Me catch basin catch basin. by more than 1096. Trash or debris in the catch basin that exceeds No trash or debris in the catch basin. 'l,the depth from the boflom of basin to invert the lowest pipe into o�out of the basin. Dead animals or vegetation that could generate No dead animals or vegetation odors that could cause complaints or dangerous present within ptch basin. gases(e.g.,methane). Deposits of garbage exceeding 1 cubic foot in No condition present which would volume. attract or support the breeding of inseds or rodents. Damage to frame Comer of frame extends more than'/.inch past Frame is even with curb. andlor top slab curb face iMo the street(If applicable). Top slab has holes larger than 2 square inches or Top slab is free o(holes and cracks. aadca wider than'/.inch. Frame not sitting flush on top slab,i.e.. Frame is sitting flush on top slab. separation of more than'/.inch of the frame from the top slab. � Cradcs in walls or Cradcs wider than'.4 inch end longer than 3 feet, Catch basin is sealed and bottom any evidence ot sod particles entering catch struclurally sound. basin through cxacks,or maintenance person judgea thffi caMh basin is unsound. Cracks wider lhan'r4 inch and Ionger than 1 foot No cradcs more than'/.inch wide at at the joint of any inleVoutlet pipe or arry evidenoe the jarri of inleUouUet pipe. of soil partides entering ptch basin through aadcs. SettlemenU Catch basin has settled more than 1 inch or has Basin replaced or repaired to design misalignment rotated more than 2 inches out of alignmenL standards. Damaged pipe joints Cradcs wider than'/-inch at the joiM of the No cradcs more than Y.-inch wide at inteVoutlet pipes or arry evidence oi soil entering the joir�t of inleUoutlet pipes. the catch basin at the joint of lhe inleUoudet pipe�. Contaminarris and Arry evidence of contaminants or pollution such Matenals removed and disposed of pollution as al,gasaline,concrete slurries or paint. acxording to applicable regulations. Sou�oe control BMPs implemented if appropriate. No contaminants present other than a suriace oil film. InIeUOullet Pipe SedimeM Sediment filling 20%or more of the pipe. InleUoutlet pipes dear of sediment. accumulaGon Trash and debris Trash and debris accumulated in inleUoutlet No Uash or debris in pipes. pipes(indudes floatables and non-floatables). Damaged Cracks wider than'r4-inch at the joint o(the No cracks more than'h-inch wide at inleUoutlet pipes or any evidence of soil entering the jaint of the inleUoutlet pipe. at the joinls of the inleUouUet pipes. • � 2009 Surface Water Design Manual-Appendix A l/9/2009 A-9 ' __ APPENDIX A MAMTENANCE REQUIREMENTS FLOW CONTROL,CONVEYANCE,AND WQ FACILITIES ,_ ,_`� NO. 5-CATCH BASINS AND MANHOLES � t _ Mairrtenance Defect or Problem CondfUon When Maintenance is Needed Results E�cpected When � - Componeirt Mairtte�anca is PeAormed - Metal C�ates Unsafe grate opening Grate with opening wider than'/�inch. Grate opening meets design (Catch Basins) standards. i� Trash and debris Trash and debris that is blodcing more than 20% Grate free of Vash and debris. of grate surface. footnote to guidelines for disposal - Damaged or missing Grate missing or broken member(s)of the grate. Grate is in place and meets design Arry open structure requlres urgerK standards. maiMananca. � _ Manhole CavedLid Covedlid not in place Covedlid is missing or ony partially in place. Cover/lid protects opening to �� Arry open atructure requires urgeM structure. maintenanca. � Lodcing mechanism Mechanism cannot be opened by one Mechanism opens with proper tools. Not Working maintenance person with proper tools.Boks � cannot be seated. Selfaocking coverAid does not worlc. ( CoverAid difficult to One maintenance person cannot remove CoverAid can be removed and ( Remove coverAid after applying 80 Ibs.of liR. reinstalled by one maintenance person. . l ��-.:� , l � ) _,, �i _-� , ,, __.� � � � � _ ' .-.i • � I/9/2009 2009 Surface Water Design Manual—Appendix A n-in APPENDIX A MAINTENANCE REQUIREMENTS FOR FLOW CONTROL,CONVEYANCE,AND WQ FACILIT[ES � NO. 6-CONVEYANCE PIPES AND DITCHES � MaiMsnanco Oefect or Problem Co�diNons When Maintenance is Needed Results Expected When Component Maintsnance is Performed Pipes Sediment 8�debris Accumulated sediment or debris that exceeds Water flows freely through pipes. accumulation 20%of the diameter of the pipe. VegetatioNroots Vegetation/roots that reduce free movement of Water flows freely through pipes. water through pipes. Contaminants and Ar►y evidence of coMaminaMs or pollution such Materials removed and disposed of poltution as oil,gasoline,ooncrete slurries or paint. according to applipble regulations. Source oontrol BMPs imp�emented'rf appropriate. No contaminants present other than a surface oil film. Damage to protective Protedive coa6ng is damaged;rust or corrosion Pipe repaired or replaced. coating or corrosion is weakening the sUudural integrity of any part of PiPe• Damaged Any dent that decreases the cxoss section area of Pipe repaired or replaced. pipe by more than 20%or is detertnined to have weakened stnictural i�tegrity of the pipe. I Ditches Trash and debris Trash and debris exceeds 1 cubic foot per 1,000 Trash and debris Geared from I square feel of ditch and slapes. ditches. Sediment Accumulated sediment that exoeeds 20%of the Ditch Geaned/flushed of all sediment accumulation design depth. and debris so that it matches design. � Noxious weeds Any noxious or nuisance vegetation which may Noxious and nuisance vegetation ' constitute a hazard to Courriy personnel or the removed acxording to applicable public. regulations. No danger of noxfous vegetation where County personnel or the public might normally be. I Contaminants and My evidence of contaminants or pollution such Materials removed and disposed of I � pollution as oil,gasoline,concrete slurties or paint. according to applipble regulations� ' Source co�rol BMPs implemented ff appropriate. No contaminants present other than a surface oil film. Vegetation Vegetation that reduces free movemeM of water Water flows freely through ditches. through ditches. Erosion damage to Any erosion observed on a dkch slope. Slopes are not eroding. slopes Rodc lining out of One layer or less of rodc epsts above native sal Replaoe rodcs to design standarcJs. place or missing(If area 5 square feet or more,any exposed native Applicable) soil. ,_� `�_J � ',__i s • � 2009 Surface Water Design Manual—Appendix A 1/9/2009 n-ii