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Home My WebLink About03242 - Technical Information Report - Drainage i s,�,�v y L�,�E 32 4 2 STORM DRAINAGE REPORT FOR SI30RT PLAT 2142 I71�tION AVE NE RENTON, WASHINGTON City of Renton File No. LUA-OS-018 FOR KEITH MENGES K&M CONSTRUTION 1615 NE 28�' Street Renton, WA 98056 F1LE NO. 798-004-031 PREPARED BY TOUMA ENGINEERS 6632 SOUTH 191ST PLACE, SUITE E-102 KENT, WA. 98032 (425) 251-0665 June 28, 2005 ZR � ?'� a � � x �) 1� SI AL � EXPIRBS 6 22 07 TABLE OF CONTENTS Pages I. PROJECT OVERVIEW 1-5 lI. CONDITIONS & REQUIREMENTS SUMMARY 6-7 III. OFF-SITE ANALYSIS &14 DOWNSTREAM BACKWATER CHECK IV. FLOW CONTROL & WATER QUALIT'Y 15-29 V. COIVVEYANCE SYSTEM ANALYSIS AND DESIGN 30-31 VI. SPECIAL REPORTS AND STUDIES 32 GEOTECHNICAL REPORT 32a-i VII. BASIN AND OTHER COMMUNITY AREAS N/A 33 VIII OTHER PERMITS 33 IX. EROSION/SEDIMENTATION CONTROL DESIGN 34 �I X. BOND QUANTITIES WORKSHEET N/A XL MAINTENANCE & OPERATIONS MANUAL N/A r I. PROJECT OVERVIEW This project consists of one parcel of land appro�mately 0.93 acres plus a b' by 143' strip of land for a portion of the access easement acres for a total of 41,183 square feet, 0.96 acres. The project is situated in the northeast end of the City of Renton. 1t is located within northwest quarter of Section 3 Township 23 North, Range 5 East W. M. The proposal is to create 41ots, "Fill in" subdivision. Access to the proposed project will be via from Union Avenue NE situated west of the property. There exists a house on the property with aspalt and gravel driveway and parking. The owner is planning to remove the e�citing structures to make way for the proposed 4 lots and private access. The soils on the site are composed of Alderwood (AgC)gravelly and loom fine s�and per the King County Soil Survey. The Alderwood series is made up of somewhat moderate drained soils that formed under conifers in sandy, recessional and stratified glacier drift. This type of soil is designated by King County as Type C soil and is marginal for infiltration systems. The site is flat with an average slope of 2 to 4 percent. There are no steep slopes present on the site. The flow consists of sheet flow from east to west to southeast corner of property. There exist storm system on Union Avenue NE consisting of underground pipe, which may serve portion of the proposed short plat, the remaining storm will be directed easterly into the existing storm conveyance pipes and catch basins located in Vashon Ave NE. The proposed development of the property is considered as "infill" project and it is located in a Single Family (SF) zone. The City of Renton designates the site with the SF zoning. The SF , zoning allows for a minimum lot size of 5000 square feet and a maximum density of 8 units per acre. The setbacks allowed in the SF zone are as follows: front yard setbacks, 20 feet; rear yard setbacks, 20 feet, and side yards setbacks, 5 feet on all interior lots, and 15 feet on corner lots. The City of Renton Comprehensive Plan designates the site as Single-Family Residence, which is consistent with present zoning. � The density for the developed portion calculates at 5.97 dwelling unit per net developed acre. There is no right of way to be deducted from the site. The proposed lots will be served from existing roads or private access easements. Union Avenue NE is fully developed street, there will no off-site improvements rec�uired for this development. Majority of trees will be retained except for few trees that fall within the building envelope of tlie proposed new lots. There will be no land to be dedicated to the City on this project. Pg. - 1 . — • _-- -- sEt�59�1�F _ ---� 6 2 a ��_ _ . 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A `n � 1.' ��.^+.�'A 1r Y ¢i..i({�.k. �` o ,{� a y � • �I . •j��1% Z�I.t� yM i�S`�'.r7�s�- a►aA (�9�� ' '�,..i__ �� wl d I• � ��;. .�d 5»,� .�'. �� .Y� ' O J) 4t ` .+ {, tl �'' i � ��j , • 1,•� -..R+ `ir��iw7� 7'�.s ��j� C.� �R�� i7' � .� S • ��ae �av �� . � /� � �� ' � �� ` �� 1', ay$ �� -��I ' � � i ' rrtn A raa � ��. � . � , , �� ) l., i iMAP - Pro e Information Plannin � ��.• -� �� a �� j �`� -�'--�-�' �•�s ��. �{ ��i'�'�!,..� ' 3� 4 . �-�... .i 4�, � � :�utr�t� ;�- �� N� «r�t�:N��_ �"" :.��"'�,�.. . �' E �� <. �� , ,, . • ,: �... ..�._�' � "�„�, �„� ,� . ; .^ . '� }r,� r �.".�._ . � ' � � . � _ .. _ _.''"�"I�"'��' - -3i a � 4 .., �S � . �'�l'. ~ ': � . • ' � ,�� ' R-�. �� 1'# ' �„� � " �� i � � -h ., �±'v M��'u� .�� <� if;a, '�c;� .� �� •�' # � ° � �µ�� —._ �z ; ,��, �.., t,, d _� f - ,�,� �:. '�1 h,�Y t '4"� �• .iw` � ��.�!� .. ;;ac� .^.. ��!-j�fri! �'f f"'. .'�"a .�.. �f� . � x . . ..� _ � � i , , l . � � � . . p� � '� � � .�� I '�.. � .".. . �a� •;��',a I . � � ; � a �.. ` p `� ,� k '`'� � '��" r'k. . .�"�€'��'a �', s �� 'a� �r.�.� . '"� __ ;,� _ * , � � �r � ��a —� __ _ _ _- .. �; :5�,�;x,i m ' . ; ,,y,.�: 3 .�„ � — *,, �. ��,. '. `�/ �'�� x�� s, �sY- 3rt� � �_� . __ f � �F ..y.�'',. � .�.. .. �„�,;�,.,,ry ; :.. '- �r�a '. . � ��h `� 4� '-�:�r�, '� ` e�`a'�' t� #`ir '�'��:�•:�.�{,s+.. � ""`. rE � � � �"r_ �� -.. � Y�1T � �,'-{� � �:�� 'Y " a�� P � J , � a[ �� . " �� ! , _ . .< .-SC1<`A3KirgCounty��ri� ' � �-.._ ��.. v * "� ,h�:: _. _ � �"#��" �(1 �.,027m� , SITL � �X. ISTJNC� CDN� � i1uNS I�� - � � , 1L PREL[MINARY CONDITIONS SUMMARY CORE REQUIREMENTS l-5 CORE REQUIREMENT #1: DISCHARGE AT NATURAL LOCATION The allowable outflows from the site will be discharged to its natural locations. If any level l flow control is calculated and/or required it will be directed westerly to Vashon Ave NE. CORE REQUIREMENT #2: OFF-SITE ANALYSIS A level one downstream analysis is a portion of this report. See the analysis later in this report below. CORE REQUIREMENT #3: RUNOFF CONTROL The increased peak runoff, due to any change in pervious conditions and increase of impervious areas, will be calculated using the 1990 edition of the KCSWDM. lf detention is calculated to be required using the 1990 edition, the final detention must size the detention using the 1998 KCSWDM. Initial calculation indicates there is n�� j�tenti��n f��rilit�� re��irr��1 Plea�e rf�fcr tu �� attached calculations in section 4 of this repor t The additional impe ' e y t �s propose �� less than 5000 square feet, thus ex m design and installation o it ta►ik, pu� or bio-filtration ' � ar facilities. ��S j��,,� r�v�scc( .. CORE REQUIREMENT#4: CONVEYANCE SYSTEM Conveyance system is minimal for this proposed short plat. Storm runoff from private road and new homes will be directed to Vashon Avenue NE. CORE REQUIREMENT #5: EROSION/SEDIMENTATION CONTROL PLAN The erosion control plan will be designed using the 1990 King County storm manual. Silt fences will be used to intercept silt laden material resulting from clearing and/or construction of short plat improvements. These facilities will be adhered to minimize any irnpact to downstream or offsite areas. CORE REQUIREMENT #6— MAINTENANCE AND OPERATION N/A Pg. - 6 CORE REQUIREMENT #7— FINANCIAL GUARANTEES AND LIABILITY N/A SPECIAL REQUIREMENTS: THOSE APPLICABLE TO PROJECT 1. Critical Drainage Area -N/A 2. Compliance with existing Master Drainage Plan - N/A 3. Conditions Requiring Master Drainage Plan - N/A 4. Adopted Basin or Community Plans-N/A 5. Special Water Quality Controls—N/A 6. Coalescing Plate Oil/Water Separators—N/A 7. Closed Depressions - N/A 8. Use of Lakes, Wetlands, or Depressions for Detention - N/A 9. De(ineation of]00 Year Flood Plain -N/A 10. Flood Protection for Type 1 and 2 Streams - N/A 11. Geotechnical Analysis and Report - N/A 12. Soils Analysis and Report - N/A Pg. - 7 11I. OFF-SITE ANALYSIS Upstream Tax lot 196 fronting on Union Ave NE, lying west of this site has an existing house with splash blocks for its roof drainage. Tax lot 139 lying to the northwest is developed with a house with splash blocks for roof drainage dispersal. Both of these properties have a gentle slope to the east, with no visible drainage channels or existing facilities. A 12" storm drainage conveyance pipe is available to these properties on the east side of Union Ave NE. Downstream The present project site slopes down to the east across the property and in the existing condition sheet flows over lot 295 and 296 of Glencoe Div 2 to Vashon Ave NE. We plan to pick up surface flows from the proposed asphalt road and pipe the runoff to the existing storm conveyance system located in Vashon Ave NE. The new 12" pipe is to be installed within the existing sewer utility easement located between lots 296 and 297. A new type 1 catch basin will have to be installed on the west side of Vashon Ave NE. A new 12" pipe will direct runoff to an existing Type 1 catch basin about 27' southwest. A Downstream Sketch is attached on the next pages that shows the existing storm drainage system per the City of Renton technical services maps and information. Catch basin 9,C5-1 1 drains to CB 9,C4-6 with about 230' of 12" concrete pipe to Whitman Ave NE. About 600' of 18" concrete pipe drain along Whitman Ave NE to NE 20"' ST. From CB 9,C5-7 264' of 18" concrete pipe flows to the east to Anacortes Ave NE. 24" concrete pipe in Anacortes Ave NF�. flows southerly then west along NE 17`�' St to Union Ave NE. The pipe in Union Ave NE � � as 24" concrete pipe and leads to an out fall to Honey Creek about 850' south of NE 17`h ' Pipe flow backwater calculations are included which indicate that the flows for the 25 year storn. do not surcharge the existing pipe network in Vashon. The 100 year storm does surcharge the 1� pipes but they do not overflow the grates. All of the downstream Drainage catch basins appear to be in the streets with curb and gutter, and therefore will contain any minor grate backups and minimize any effect to adjacent properties. Pg. - 8 „ � .. , - 1 ;� � �� ,� , � � �LH, ;�r� _. .. . . � �` � _ -- - - - � �='-- --- -- _ -- - ._ ._.__-- --------__,�-__.__ � ra Q ' � ---�------ -?. . 9�'6 . � � I . � ..-.��!'t. �- Oj � 6 Tj 9-9 6 L-9 6 � pT�t.gg 6 � � , 's �' ,r.� 9� � � � � Y-9�'6 . � -9H`6 Q'6 , ;��,,. J.- J / '-.. � t �'. 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'L�—`��' ' 1 ��. �,, t i I - - , ' /l _ - . � , 1�� i . r �ti I _1 �� ' �r-S �b � I � � � �� f � �� ,s�•2; � �l ,. ;r� ; :� � I�zi^ £2 ,�� i : ' � � ' P � � ��. � � , _ , , � � � >,ti•. � I �s c7N�i �N �� v �, r � 'ti `, � � 'L, ' � i , �' «ti. 8�-,L22 :, r � f � ,. � -- � �ti. �� -b�b. �► , ' � � . , _ , __ -_ ` � \_ •ti. i i �i �, � l__cl l� (iNl.Z �N ' � IS:�lN7Qt �S : ` i j Y z `c:� Z =I � j .y I � o , i'� I f ,•^ � 1 # z { I � ( i) ( 1 � `J� m I i I ' � m�� , I`, 1:,1111 �� I �� ' � "'--� ; ; �� I isi��rr ,�� I ` - -- - ; � � � i � , � � � � : � 1 � ji I ! �_ . �; ; � , �-- � � ' ( ' � � __ � , .? j a � � �i_._�_ , , � � � .�o � ��i • � a.;[Inactive KIRT5] ::�%�4 A Production of Runoff 1'ime Series F:•o,ject Location : Sea-Iac Computing Series : BASIHlS.tsf Regional Scale Factot• : i.�e i Data Type : Reduced Creating 15-ininute Time Series File Loadi.ng 73me Serfes File:C:�)(C_S4JDtt\I(C�A7f1�STTGISR_rnf R ?ill Grass 1_74 acres Scaling Yt•: 6 Loading 71me Series Pile:C:�HC_SHDf1\NC.�AI'A�SiF.t_15R_r�f 8 I�npet•�ious 1.94 acres Adding Yt•: 8 7ota1 Area = 3.73 ac:•es Fenk Discl�arges 3.19 CFS at 6=30 on Jan 9 in Yeat• B Storing Time �ieries File:BARINiS.t�f R 7ime Series Computed ------------------------------------------------------------------------------- ifCRTS Comm�nd e}{it KCRI'S Progr�m KCRi'S Pz•ogram Uers ion 4.42b run complete I �� - � I I , ` Flow Frequency Analysis Time Series File:basinl5.tsf P 'ect Location:Sea-Tac ro� ---Annual Peak Flow Rates--- -----Flow Frequency Analysis------- Flow Rate Rank Time of Peak - - Peaks - - Rank Return Prob (CFS) (CFS) Period 0.924 6 8/27/O1 18:00 3.19 1 100.00 0.990 0.690 8 1/05/02 15:00 2.14 2 25.00� 0.960 � 2.14 2 12/08/02 17:15 1.35 3 10.00 . �--------�-- 0.744 7 8/23/04 14:30 1.31 4 5.00 0.800 1.35 3 11/17/04 5:00 1.15 5 3.00 0.667 1.15 5 10/27/05 10:45 0.924 6 2.00 0.500 1.31 9 10/25/06 22:45 0.744 7 1.30 0.231 3. 19 1 1/09/08 6:30 0.690 8 1.10 0.091 Computed Peaks 2.84 50.00 0.980 Us� rn2 i�Rc �c �.��va � �= r� r �r} l_ �_ r� L ►� 7 , �� I �� — i Z BACKWATER COMPUTER PROGRAM FOR PIPES Pipe data from file:SHADY.bwp Surcharge condition at intermediate junctions Tailwater Elevation:426.94 feet z �- yrp�L= Z.��C-�S ��)l Discharge Range:l. to 3.5 Step of 0.1 [cfs] ( �Q ,�f�� _. � j��- �� - Overflow Elevation:436.2 feet IvIINO►2 S(�1QC�'IAR� Weir:NONE Upstream Velocity:0. feet/sec PIPE NO. 1: 230 LF - 12"CP @ 0.90�h OUTLET: 426.94 INLET: 429.00 INTYP: 5 JUNC NO. 1: OVERFLOW-EL: 934.10 BEND: 0 DEG DIA/WIDTH: 4.0 Q-RATIO: 0.00 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI **�*****************�**�**�******�*+**�***********�***�+*�******�*��**��*�� 1.00 0.57 429.57 * 0.012 0.43 0.36 0.00 0.36 0.43 ***** 0.57 1.10 0.59 429.59 * 0.012 0.45 0.38 0.00 0.38 0.45 ***** 0.59 1.20 0.62 429.62 * 0.012 0.47 0.40 0.00 0.40 0.47 ***** 0.62 1.30 0.65 429.65 * 0.012 0.49 0.42 0.00 0.42 0.49 ***** 0.65 1.40 0.66 429.68 * 0.012 0.51 0.43 0.00 0.43 0.51 ***** 0.68 1.50 0.70 429.70 * O.a12 0.52 0.45 0.00 0.45 0.52 ***** 0.70 1.60 0.73 429.73 * 0.012 0.54 0.47 0.00 0.47 0.54 ***** 0.73 1.70 0.75 429.75 * 0.012 0.56 0.48 0.00 0.46 0.56 ***** 0.75 1.80 0.77 429.77 * 0.012 0.58 0.50 0.00 0.50 0.58 ***** 0.77 1.90 0.80 429.80 * 0.012 0.59 0.52 0.00 0.52 0.59 ***** 0.80 2.00 0.82 429.82 * 0.012 0.61 0.53 0.00 0.53 0.61 ***** 0.82 2.10 0.84 429.84 * 0.012 0.62 0.55 0.00 0.55 0.62 ***** 0.84 Z'��1 2.20 0.86 429. 86 * 0.012 0.64 0.56 0.00 0.56 0.64 ***** 0.86-D k 2.30 0.88 429.88 * 0.012 0.65 0.58 0.00 0.56 0.65 ***** 0.88 2.40 0.90 429.90 * 0.012 0.67 0.60 0.00 0.60 0.67 ***** 0.90 2.50 0.92 429.92 * 0.012 0.68 0.61 0.00 0.61 0.68 ***** 0.92 2.60 0.94 429.94 * 0.012 0.70 0.63 0.00 0.63 0.70 ***** 0. 94 2.70 0.96 429. 96 * 0.012 0.71 0.64 0.00 0.64 0.71 ***** 0.96 2. 80 0. 98 429. 98 * 0.012 0.72 0. 66 0.00 0.66 0.72 ***** 0. 98 2.90 1.00 430.00 * 0.012 0.74 0.68 0.00 0.68 0.74 ***** 1.00 3.00 1.02 430.02 * 0.012 0.75 0.69 0.00 0.69 0.75 ***** 1.02 3`�q 3.10 1.04 430.04 * 0.012 0.76 0.71 0.00 0.71 0.76 ***** 1.04 3.20 1.07 430.07 * 0.012 0.77 0.73 0.00 0.73 0.77 ***** 1.07��lc 3.30 1.10 430. 10 * 0.012 0.78 0. 75 0.00 0.75 0. 78 ***** 1. 10 3.40 1.13 430.13 * 0.012 0.79 0.77 0.00 0.77 0.79 ***** 1. 13 3.50 1.15 430.15 * 0.012 0.80 0.79 0.00 0.79 0.80 ***** 1. 15 � 3.50 1. 15 430. 15 * 0.012 0.80 0.79 0.00 0.79 0.80 ***** 1. 15 PIPE NO. 2: 142 LF - 12"CP @ 0.81$ OUTLET: 429.00 INLET: 430.15 INTYP: 5 Q(CFS) HW(FT) HW ELEV. * N-FAC DC DN TW DO DE HWO HWI , ��*�****��*****+�****��***�*��+��*��****�**�*+*�*�*****��**��*�*�+��**+�� 1.00 0.59 430.74 * 0.012 0.43 0.37 0.57 0.57 0.43 ***** 0.59 1.10 0.63 430.78 * 0.012 0.45 0.39 0.59 0.59 0.45 ***** 0.63 1.20 0.66 430.81 * 0.012 0.47 0.41 0. 62 0. 62 0.47 ***** 0.66 1.30 0.69 430.84 * 0.012 0.49 0.43 0. 65 0. 65 0.49 ***** 0. 69 1.40 0.72 430.88 * 0.012 0.51 0. 45 0.68 0.68 0.51 ***** 0.72 1.50 0.76 430.91 * 0.012 0.52 0.46 0.70 0.70 0.52 ***** 0.76 1.60 0.79 430.94 * 0.012 0.54 0.48 0.73 0.73 0.54 ***** 0.7� 1.70 0.82 430.97 * 0.012 0.56 0.50 0.75 0.75 0.56 ***** 0.82 �� - ►3 �- _ _ 1.80 0.85 431.00 * 0.012 0. 56 0.52 0.77 0.77 0.58 ***** 0. 85 1.90 0.88 431.03 * 0.012 0.59 0.53 0.60 0.60 0.59 ***** 0.88 2.00 0.92 431. 07 * 0.012 0.61 0.55 0.82 0.82 0.61 ***** 0. 92 2. 10 0.95 431.10 * 0.012 0.62 0.57 0.84 0.84 0.62 ***** 0.95 „�1 �"'� � 2.20 0. 98 431.13 * 0.012 0.69 0.58 0.86 0.86 0.64 ***** 0. 98 2.30 1.01 931.16 * 0.012 0.65 0.60 0.88 0. 88 0.65 ***** 1.01 2.40 1.04 431.19 * 0.012 0. 67 0.62 0.90 0.90 0.67 ***** 1.04 2 .50 1.08 431.23 * 0.012 0.68 0.63 0.92 0.92 0. 68 ***** 1.08 2. 60 1.11 431.26 * 0.012 0.70 0.65 0.94 0.94 0.70 ***** 1. 11 2.70 1.14 431.29 * 0.012 0.71 0.67 0.96 0.96 0.71 ***** 1. 14� 2.80 1. 17 431.32 * 0.012 0.72 0.69 0.98 0.98 0.72' ***** 1. 17 ?_.90 1.21 431.36 * 0.012 0.74 0.70 1.00 1.00 0.74 ***** 1.21 3.00 1.24 431.39 * 0.012 0.75 0.72 1.02 1.02 0.75 ***** 1.24 � 3. 10 1.30 431.45 * 0.012 0.76 0.74 1.04 1.04 0.77 1.30 1.28 �yp,�.,�,�� j � 3.20 1.33 T 431.48 * 0.012 0.77 0.76 1.07 1.07 0. 83 1.32 1. 33 -'- 3.30 1.37 431.52 * 0.012 0.78 0.78 1.10 1.10 0.90 1.36 1.37 3. 40 1.52 431.67 * 0.012 0.79 0.61 1.13 1.13 1.08 1.52 1.41 3.50 1. 63 431.78 * 0.012 0.80 0.83 1. 15 1. 15 1. 17 1.63 1.46 3.50 1.63 431.76 * 0.012 0. 80 0. 83 1. 15 1. 15 1. 17 1. 63 1. 46 -- T) 0 (� V Y�� I�"!-O�/ ��a - �� J lV. FLOW CONTROL AND WATER QUALITY The following calculations, based upon the 1990 KCSWDM conclude that the 100-year peak flow difference between the pre-developed flow and post-developed flow is less than 0.5 cfs. ln accordance with 1990 King Count Surface Water Drainage Manual, section 1.2.3, detention wills not required. The following calculations include: Basin area sketches for existing conditions and developed conditions Time of Concentration Isopulvial graphs for 2, 10 and 100 year storms Pre-developed and Post-developed hydrographs � In discussing this matter with the owner, we ascertained that the roof area each home will average about 1500- 2000 square feet. The existing soils for this site are mapped according to the King County Soils Survey as AgC, Alderwood. Infiltration systems for roof drains are not recommended for this soil type per the Icicle Creek Engineers Geo-Technical report. A cc�� i� included in Section VI of this reE The Santa Barbara Urban Hydro;. � :: _.: _._.. ., ..._ . .. _ . ,_. � ,:;� _:._ ._ ...... ... difference between the 100 year peak flows for the existing and developed conditions is 0 O.SScfs = 0.20 cfs. This project will be exempted from designing and constructing detentiori facilities. ; WATER QUALITY Per the attached Existing, and Developed Condition Sketches the increase in impervious surfacing that is subject to automobile tr�c or chemical storage is; Total private road 9072 SF Ex. Ac driveway 2015 SF 7057 SF greater than 5000 SF Water quality is required and will be designed per the 1998 KCSWDM. Pervious Area = 22,1 l 1 SF Impervious Area = 19,072 SF The wet-vault permanent pool will be sized per section 6.4.1.], page 6-68 of the 1998 KCSWDM. Pg. - 15 ur= ��.9l�; -�- O.2 S A�g -F O.1 OtA�f+O.O I Ao� X �W 1 Z� V� = volume of runoff from mean annual storm A; = area of impervious SF A{B= area of till grass soil covered with grass SF A,f= area of till forest soil covered with forest SF Aa = area of outwash soil covered with grass or forest SF R = rainfall from mean annual storm(figure 6.4.1.A) = 0.47" V� _ (09(19072) + 0.25(22111) ) x (0.47/12) _ (17165 + 5528) 0.47/12 = (22,693)(0.47/12) = 889 CF Vb = 3(889) = 2,667 CF The water quality will be in a tank. Per Section 6.4.2.2 on page 6-81 of the KCSWDM, the culvert section must provide the same top area as that of a vault with vertical wall with an average depth of 6 feet. The calculated tank is 83 feet long. A vault 83 feet long and 6' deep would require a top area of: 2667CF/(6') =444.5 SF required. Use the figure on page 30 for the 7' diameter tank to check the required surface area within the tank. 83' X 5.44' wide = 45l.5 SF OK ! _. __._._.. � , r � " I Pg. - 16 � . � � I I� + � _ _ � . I � � 1 _ .: , I - _ . - - 1- - - - _ L _ _ _ _ L v 1 I . I � Narsr+s.w �- ��.er ea.as• ,+,.e�, � I � _ .._--: \ � i � � l__T_� \ I Z I _ � � � � \ � < � -- _ _ _ � � �� -��__ __ o� � � ( �"_::��:� _- �t_..r � � h � � ; ` a�ir�rt am— — — — ` �� I I a � ,p� I'; I � rxw' serusrc I Fro�'""°�en�1 � !I _ . -r'� ;� , .:� � q L-———r��'�- �,1' \ � I {'r� � -�� ' � o'� _ ---4` ` �� \ ' -� I �,,__ �-———� a I �'�a�"< ��,.��,,�►�--..__r. �' � � / � ` LL - , c3 / a�►� � � ;:r.........�.................... r....'w u,xoo' L 1 � � � .e��.- R�;--�_�""'-- -.... •-- -•�—� "°�_y— —� «o /f / E�--•-• •--_..... . ._"•-. �wNt►M -^ — +"_ .__— _�=—_ -- — �� ___ � —__ � � ��_L" ti,nn�, .i.._ �61�n Gt ��-'�ti�.._h— -�--•—__ 4i 1' """""' � r' . ..."'•'...""'...�. •��Q61s��_��.��':'� �.��'17QDF,.��_�__�� \\ � / � � �.f� .� IAiLI�If � _ .. .o ,.\; � .. \ "� � \ �\ /� i/ 1 . ��.,. r s�.e�� Ie x�. �p�_..�� ... . -3—N �;'v\\ I \ \ . \� / �< / � � �� _ � � �� , I � � � _ _./_�: � + TOTAL AREA= 41,183 SF - 0.�95 AC � - - 1 �' � � � �.._ ! -- � LANOSCAPING -LAWN = 29578 SF - 0.68 AC � � �� i -�_ HOUSE & CONC PADS = 3720 SF - 0.09 AC. � / ' - i � „ , ASPHAL T D/W = 2015 SF - 0.05 AC / � ' � 6 O �RA VEL D/W = 5870 SF - 0.13 AC �' � � _ PERVIOUS AREA = 29578 SF - 0.68 AC / IMPERVIOUS AREA = 11,605 SF - 0.27 AC � , � � i , � SKETCH EX. CONDI TIONS SAIVD Y LANE SHORT .PLA T i � I - I � I � � - - - - - L- ,_._ _ � _ � � I � - - - - - - L " - I — �errr�rr � 2�aer _ I 6a8Y' I � 1M.EpQ' r � � WI' � � � LOT 2 LOT 3 \ z ,o.o�..a�. \ �� I _. . � 7.=7!»R � 0.]3�er� � <� � 0.17 eerw � I =��-::��'- � , � >> ._ -- - _ . gy _ I i! I �_ ` �� _� p 'M'/'y e _., '�� $ LOT 1"'�°�' srrua,t ' �`�=� ;�� '�� - --��'� _ � � � I �.�,% I . � a"�`�."' � � �' LOT_4_ �r � I '� ' . 0{ . I �4�6, 6.767�0.R � \ � \ / �'- 1: ' N„ y �._..-- - '"' :. _ / � ;y , saT.uu,r.aaor � `�"` �� ,,� / � � -� . \\ � e � I µ � � � • -�,,\ \�M�.#,J ._ .- ' ��\\ � \ - � , � � , I ��; r.wss-,:�. .._ .,..�.. � I �-- ' ,� / I ��^ ��lYll �'X 'B� \�'\ \ � L.�10.s.��Y +lYs c.dd� `�� ' � -- \ \ _ , � � �,� � � _ ��_ II j � \ \ _ v..,� y.✓�_" �� ' � ► _ - \ / � I �-�� _ � °� �M=6o� ` y' � � � . .� , ,� � TOTAL AREA= 41,183 SF — 0.95 AC / I LANOSCAPING —LAWN = 22,111 SF — 0.52 AC HOUSE & 0/W'S 2500SF/EA � f0000 SF — 0.23 AC. SKETCH DEV CONDI TIONS ASPHAL T PRlVA TE ROAD = 9077 SF — 0.20 AC PER�IOUS AREA = 22,»> sF - o.s2 Ac �S,�D Y LANE SHOR T PLA T IMPERVIOUS AREA = 19,072 SF — 0.4,� AC TIME OF CONCENTRATION - PRE-DEVELOPMENT- FOR 10-YEAR, 24-HOUR STORM DESIGN SHEET FLOW- ONSITE MANNING-n 0.15 OVERLAND-L 300 FEET PRECIPITATION-P 2.91NCH SLOPE- S 0.027 FT/FT T1 = 21.98 MINUTES TOTAL TIME -PRE-DEVELOPMENT 21.98 TIME OF CONCENTRATION- POST DEVELOPMENT- FOR 10-YEAR, 24-HOUR STORM DESIGN SHEET FLOW-ONSITE MANNING-n 0.011 OVERLAND-L 300 FEET PRECIPITATION-P 2.91NCH SLOPE- S 0.03 FT/FT T1 = 2.61 MINUTES USE 6.3 minutes �� - � �1 10 - RDFAC 11 - RETURN TO DOS ENTER OPTION: 2 SBUH/SCS METHOD FOR COMPUTING RUNOFF HYDROGRAPH STORM OPTIONS: 1 - S.C.S. TYPE-lA 2 - 7-DAY DESIGN STORM 3 - STORM DATA FILE SPECIFY STORM OPTION: 1 S.C.S. TYPE-lA RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 2,24,2 ---------------------------------------------------------------------- ******************** S.C.S. TYPE-lA DISTRIBUTION ******************** ********* 2-YEAR 24-HOUR STORM **** 2.00" TOTAL PRECIP. ********* ---------------------------------------------------------------------- ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 .68,86, .27, 98,21.98 DATA PRINT-OUT: AREA{ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN 1.0 .7 86.0 .3 98.0 22.0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) .20 7.63 3814 ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: lE2YR SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP C ---------------------------------------------------------------------- ENTER: A(PERV} , CN(PERV) , A(IMPERV) , CN{IMPERV) , TC FOR BASIN NO. 2 .52, 86, .93, 98, 6.3 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) R CN A CN .9 .5 86.0 .4 98.0 6.3 PEAK-Q(CFS} T-PEAK(HRS) VOL(CU-FT) .30 7.83 4371 ENTER [d:] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: 1D2YR SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP �� 2 �� 10 - RDFAC 11 - RETURN TO DOS ENTER OPTION: 2 SBUH/SCS METHOD FOR COMPUTING RUNOFF HYDROGRAPH STORM OPTIONS: 1 - S.C.S. TYPE-lA 2 - 7-DAY DESIGN STORM 3 - STORM DATR FILE I SPECIFY STORM OPTION: 1 S.C.S. TYPE-1A RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 10,24,2.9 ---------------------------------------------------------------------- ******************** S.C.S. TYPE-lA DISTRIBUTION ******************** ********* 10-YEAR 24-HOUR STORM **** 2.90" TOTAL PRECIP. ********* ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 . 68, 86, .27,98,21.98 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC{MINUTES) A CN A CN 1.0 .7 86.0 .3 98.0 22.0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) .36 7.83 6477 ENTER [d: ] [path] filename[.ext] FOR STORAGE OF COMPUTED HYDROGRAPH: lElOYR SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP C ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 2 .52,86, .43, 98,6.3 DATA PRINT-OUT: AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN .9 .5 86.0 .4 96.0 6.3 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) . 51 7.67 7142 ENTER [d: J [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: 1D10YR SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP t��7 -- Z � � , 10 - RDFAC 11 - RETURN TO DOS ENTER OPTION: 2 SBUH/SCS METHOD FOR COMPUTING RUNOFF HYDROGRAPH STORM OPTIONS: 1 - S.C.S. TYPE-lA 2 - 7-DAY DESIGN STORM 3 - STORM DATA FILE SPECIFY STORM OPTION: 1 S.C.S. TYPE-lA RAINFALL DISTRIBUTION ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 100,24,3.9 ---------------------------------------------------------------------- ******************** S.C.S. TYPE-lA DISTRIBUTION ******************** ********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAI, PRECIP. ********* ---------------------------------------------------------------------- ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1 .68, 86, .27,98,21.98 DATA PRINT-OUT: I � AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN 1.0 .7 86.0 .3 98.0 22.0 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) .55 7.83 9611 ENTER [d: ] [path] filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH: 1E100YR SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP C ---------------------------------------------------------------------- ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 2 .52, 86, .43,98, 6.3 DATA PRINT-OUT: AREA(ACRES} PERVIOUS IMPERVIOUS TC(MINUTES) A CN A CN .9 .5 86.0 .4 98.0 6. 3 PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) .75 7.67 10356 ENTER [d: ] [path] filename[ .extJ FOR STORAGE OF COMPUTED HYDROGRAPH: 1D100YR SPECIFY: C - CONTIiJUE, N - NEWSTORM, P - PRINT, S - STOP �,g - Z z KINC COUNTY, WASHINGTON, S URFACE WATER DESIGIY M ANUAL FIGURE 3.S.1C 2-YEAR 24-HOUR ISOPLUVIALS �, � r�: - - � - --P - �_ �-- -- _�,f. - - - , � � ,, ._� :� �, `,z ,_ - �• f _ �' _ 's� ��'_ t `�`�� ) I -,_, r.� _ - -�.: � � J _ •, l�i '; ' _ �; ,�s i t � / A�`� i- _ ./% NYMI�1 '� .� L /� -� �` ��.� r p � �'I �� ' — - - 1�` `4 -- - �r �� N�- r� . �` - �.�'° - �� J ` - � . � 2. jM = Cr - ` � . 4 \� ` - 1 � / � � � 1�~ � �^ 3N � ----- ..... �~ ( � �Q \ r/ � IYIIYI - t'\ �_�. � �, � •. 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"p ` � � N I —u� ' � - —-� _ __ ', u ,' � �'��, t� �` -�� 2-YEAR 24-HOUR PRECIPITATION � ' . � , ` _ � _ . ,.3.4�"' ISOPLUVIALS OF 2-YEAR 24-HOUR �► � - -•� -� y '+ 35 TOTAL PRECIPITATION IN INCHES — •� s - °F �L'N .�, _j ` - � 0 1 2 3 4 5 6 7 s Mll�s � 3 ^_•,/ � ��' � � \ / `� � � �JI i:aoo,000 �l �'�� -��,,� " 3.5.1-8 ��`�`� i/90 � KING COUNTY, W ASHINGTON, SURFACE WATER DESIGN MANUAL FIGURE 3.S.lE 10-YEAR 24-HOUR ISOPLUVIALS 2.1 ---- - -- '�' - - �+, '.in - xu—=�' - -� - -- - - - --- — --- - '�Z \ ., � .- r' � \:� y � � .. , , , ,. � � : /" . _ -- Zj� ' � . � � 3 � ' s '� �, ��... � 4- _ �,,, -._� � 24 � �__ .. ` �f _ `, ` ' Y:s� �.��_y � 4/ 0,� �� / � ` .1: � — ,;'%`' �MM�::/ ��'�`� / - .' -_� ,��.."'1 ' , � f�_i" ?6 � - - � �. �' f �.� �7 i ' :J:__ � � � '' :fl �. ?8 � - '�' r �° �- _ � � - f-`a, , � '. 29 � I �:�; ,-�;� - - h � r �,T� �" _. i•-- r' 3' - i I �"� 3p .\ - _j..��Eti �� ' - '�: � �� '� ,. �� i� � �,, _ _.y,�, � �� ` _ .. 4 � � '' 3� �;� 1 �:... r;,:'� �-� - �� i "` � rwe.?� �r.� � ' , �s�� - tl _ ��`,� !�''�� °�. .I' l. — - .-. �? � � 2� 1 �r (1 � �� r / _.�, �� '�r „�, �� ---- • r��"�-• ` 1 � � ' , , 33 �� ..,�..., 4 �. _•� � -.' � -�,.. - � ;. 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'� r 10-YEAR 24—HOUR PRECIPITATION ' . �- �L°� _ � -� . � `l .�� 3.4 ISOPLUVIALS OF 10-YEAR 24-HOUR �• s� 6i �, �`� TOTAL PRECIPITATION IN INCHES 3O � - � p._ T` �; 0 1 2 3 4 S 6 7 6 Mllss � � �� i•,•� �-..� _' �: o � 3.s.�-�o 3' ti �-� �� 40 300, 00 � ' . K 1 N t; 1' O U N 'I' Y, W A ti II 1 N ci 'I' (l N. 5 U R 1' A C I? W A 'f I? R I) f; S 1 (i N M A N U A i. _ __ . _-- _ — - � i I�ICUItIsJ.5.111 1110-YEAIt 24-11Oillt ISUPI.IJVIALS ------__ _.._----------_._-. 3 p � � ��t � � r�� -� �� (�. — r; ' � ;�e`� ; ,. �- .�r-- ,� �' � '� '� `' �3`� '� � _ r. .,�,=t? ..�� .� ;''� Q �- �: t �� `: f ....�\�' , 1 - i � � � 3s � _ w� � � �,.- .:=` ,� .�, rt� � , ` , 3 3> 3 ,�' : �-" � _ ` � � ,� ,, ,1 $�9, ` 'A- ` ; .�,.�" � � � ,,. - �r �,� � � 4.p � _ - ,i .Y ` �` ' r' 4.r �'t� � ., _ - .' �,_� �� `. ��' �,� - '� i" r .- i '� - •1' • 4� � � � - 4z�\ � ' - � "IC, . - — _ �,., > ',� - 1 �i � r` '�=- 1 �4- 4.3 � . __. , � °_.� .. _ �_ � � � .�.. � _ � ` ,�-' ',, "'�' -�- .>''" � O 4Q � `.. �'E _ . = u v ��' � . ' r�` � � �c — g � '� �; .° � : f� ,�� .; L .y � � ��_ ; ,�� ;� � �� q ��a'� �. � _ ' - -- f � S. 4S .�� .�..., I :1� 1 ! , � _� _ -,,, �- _ � I .�. � �, � - � (� 1 � i , � _. � .._ -- � . � ,�, � ,' j I�_. �V 'I � �..\\• � �� _ _..:a� , ,/— '� � �� ' � •r ` . � r � r � � ,� � r _ _ �. - � _ ` , ' _ ;� , �-- � �- 1 , � ,.�/ " �J r ��1,Lf' �. � ". � . ;� \�_� _ 1, t� I i i_ � �`�, i � ,` '� ,� _ `' �� /l ,� I i � '� _� ... 1 `,' 1 �- P�.��, v I � 1 �+. _ �� 1` .�� r��.,\- ) ' � �� "•�, '� '�' � •1 I� � _'� i i - , �.,.. ( - • / i - � �� L:_ �r _ � 1 � 'I � �� - •�� l - _� , .:�. r � � ��' �� .� _ .� i ,� .;. i �� y� �,�� v � �� • � �:,� z n� '�ti � ', _� .f , j. 's � ,� � ;.� ' �� `_ i .,, i i ' ; � ,� S�� - ` � -- ' - - ' � � ,� ! �.•� , � .� �^. _._ i____ � ;�- � � � r-- � �� ! �� , �� , ( � � i . �_.. i t� �._ � ~ �R� 1 � ~ � •o � -- �- �� _ _ ,�^ r� �., ti� �' �_ � - --- �� .. .. _ i h,� _ �. �, w�,' � � � '�,i ,�a. `�� , � � � i ,�' .}j � �� _� ,_, `�, �, `"�- - n' r. �r `;'��'`� �.;f-` � ;�'� •�. i � �� ,j i_.� I' I � �� '��" ;,�,� _p r r n .,. � �. � .- �� ..,., a _ ', 1 � � � 0�' � O� , '+. �Y _� . ' - �'. � 0�. `�� o� ` ' �. ., ,.r �,. 100—YEAR 24—H�UR PRECIPITATION Q ` _ _ t ;_� .4� , ' ' ' �� 6.5 �� •3A-�-�--ISOPLUVIALS OF 100-YEAR 24-HOUR �` a� 1. - � .. ,�„ �:. � 5 i TOTnL PRECIPITATION IN INCIIES Q��' �_-' " � ��\ = - a �1- 1 r,r � � j a• t �� i O 1 2 � 4 5 7 B Mlles � ,•('�,, � -- � �� .__ .--- --. _._ �1 _ 1 l�- _� �•��k. l. — – -_ 3.5.1-13 h0 '{�"'�, 1: 300,060 Ga �} � ��J�� J i I' " Z � � ,i 'I'able 1 ('cinvcrsic►n cil� SCS Sc�ii '1'Ypes to "I'il(, Outwash, ancl Wetlaiul Classilicaticiiis SCS Soil Type SC5 M�idilicd Notes l[ydrnlogic SdUH Soil Group Group Al�icrw<,nd (Ag13, AgC, AgD) . � '1'ill Arcnls, Altcrwood Material (AmB, AmC) 't�ill Arcnls, livcrctt Material (An) 13 Oulwash I Rcausi�c (Bc(', 13cD, l3eF) (' 'I ill 2 liellinKh�m (Rli) 1) 'l ill 1 Ilriscc�t (14r) U 'f ill 1 I3ucklcy (Bu) f) I ill 4 li�rlu�c>nl (lia) 1) 'i'ill 1 r�i�;��v��k ci:�i> c r�u i I;vcrcll (livll, I�.vC, FivD, EwC) A/13 Uulwash I Indian��la (In(', InA, InU) A Outwash I Kils��► (Kp{3, K��(', KpD) (' "I'ill Kl:ius (Ks('► (' (hilwash I Ncili�m (Ne(') n t)ulwash I NcwhcrF (N�) !� 'i'ill l Nnuksack (Nk) (' 'I ill �:3 Nornia (N��) U 'I'ill 3 Orcas (()rl D Wctland Oriilia lOs) U "I'ill � l)vall (()v(', Ovl), Ovl�) (. 'fill 2 I'ilchuck (Pc) (' "I ill 3 I'u�!cl (Pu) I) 'I'ilt 1 � Puy�llup (PY) Il 'I ill 3 , Ragnar (ItaC, ItriU, RaC, RaE) R Uulwash I Rcnl�>n (Re) 1) "I�ill 3 S�lal (5a) (' "Iill 3 Silllllll'JIl11tiI1 �SII) 1) 'fill 3 SC.1�l�f' (Sk) �) �UCI�:111(� Shalc:ir (Sm► U 'I ill � Si (Sn) (' 'I'ill 3 Snc�hornish (S�, Sr) U 'I'ill 3 Sull�n (Su) C �I'ill 1 'fukwila ('I'u) I) 'I ill 3 Woc►dinvillc {W��) D 'I'ill 3 I. Where c►utw�ish suils �re salurated or underlain at shallow Jepth (<5 fl! hy kl;�cial till, Ihcy sli�iulil hr. Irc�Ucil as lill s��ils. 2. 'fhese are bedr�ick soils, bul calibralion of liSPF by King Counly SWM sliuws bedrock soils Ici h�tve si�nil:ir hydrologic res��onse to till soils. 3. "These are alluvial soils, soiue of which �re underlain by glacial till or which have a seasonally high water talile. In �he absence of detailed study, these soils should be treated as till soils. 4. Ruckley soils are fonned on the low permeability Osceola mudflow. Ilydr��l��gic res�xmse is assumc�l Ic� bc sin�ilar In that for lill soils. � - z � KIN (i c' OIIN 'I' Y, WAtiI11N (i 'I' ON, S111i1� A (' I? WA 'I' I; It I� I� tiI (� N �4ANtlnl, '1'A111.L 3.5.211 S(:'S WIsS'1'i;ltN �YASIIING"fON RUNOF CURVE NUMI�1?!2S _ _ -------- - ----— - -- ---- _. _. I SCS WESIERN WASHINGTON RUNOFF CURVE NUMBERS (Pul�llshecl by SCS In 19H2) Runotl curve nunit>ers lor selecied eg�ladlural, suburben aiKl urban Innd �ise lor Type tA � rolntall dlslrlbidlon, 24-liour slorm durallon. CURVE NUMHERS BY HYI)f10LOGIC SOII_ GROIJP I IANC� USE UESCRIPTION A B G U - --- ------------- - - --..__ -- -- -----------_ ----_._.---- Cultivaled Ia�KI(1): winter condltlon 8A BI 94 95 - � ---- � Mounteln open ereae� J low growing b�ush end greeelends i 71 H2 89 �B2 ---____-------_-•------.-..._ _ --- Meadow or peswre: � cs5 7e e�y � os ------------------ —,._ ___ ----— ---- - _.._ _ . __ ' Wocxl ar lorest lerxl: u►Kllslurhec) 42 fi4 7R flt Woal or loresl land� young second growlh or b�ush 55 72 01 (16 Orclanl: wlth cover crop HI o0 92 !�4 ----._..----- - __- - _------------------- -- _ _ _ ' Open spaces, tawns. ��arks. �oll courses, cemelerles. landscaping. gaxl co�xlplon: y�ess cover on 7596 or more of Ihe erea 6t1 ft0 0� fx) talr carxlhlon; t�rass cover on 5076 ' l0 75% ol Ihe a�ea �7 e5 flU 92 __._____---_ _ --- _ _---.----- ----- - --- - -- ___ . --- ------- Oravd roads a�Kl parkln�lots 76 !)5 09 91 Ulfl f(�CI6 9fKI (lafl(II19 (O�S 72 �2 f17 89 � --- ---- ---------- �---_ ----- --- - ------ – _--— - Impc�rvbus ewfacos, pavenienl, rc�ofs, elc. 90 9A 9Ef 98 Ope��waler bociles: lakes, wellarxls, (�orxis, elc. Ic� 100 1O0 100 --- -.-----------_------__ - - --------- -_ - M Single Femlly Reskientla! (2) DwelUng Unll/Grosg Acre % Impervlous (3) 1.0 DU/GA 15 Se�iarate curve nuinh�r � 1.5 DU/(3A 20 shnll ho set�clfKl 2.0 OU/OA 25 f�tt pervlo��s pncl 2.5 DU/GA 30 Irnpervlous �orlloii 3.0 DU/GA 34 <�f ihe she or hash� , � 7.6 DU/GA 3U j 4.0 DU/GA 42 4.5 DU/GA 4G 5.0 DU/GA 40 � 5.5 UU/GA 5u 6 0 f)U/GA � 5?. ' 6 5 DU/GA 54 7 0 Ul l/GA 5r � Plen►ieri unft developnrenis, 96 bn��ervlous co�Klominlums, a��arlmenls, musl be compulecl ' coinmerclal b�islness encl � Irxlustrlal ereas. _--_-------- -- ----------- --- --- - ------ ----____�—_------------- -- -;- � - (1! For a more detalleci clescriptlon ol agricultural land use curve numbers rPler lo Natlon�d Enylnnerint� I Ilandt�ook, Sedlon 4, Hydre�logy, Ctiapter 9, Aiigusl 1972. (2) Ass�nnos rcx�f and drlveway runolf Is dlrecled Into elreet/slorm syslem. (3) The remahdn� pervioiis areas (lawn) are consldered lo be In goocl condlUori I�,r �lies� ciirve nini�i�ers _ . - _ -------- 2�-_----___ � - ).S.Z-3 �/H'� KIN (► (; OUN 'i' Y, WASIIIN (; TON, S (1RrACE WAT' ER I) ESI (iN MANIIAI, ----- -— — _ --- - '1'A111.N 3.5.2(; "n" ANI) "k" VAI,UFS USEU 1N T'IME CALCUI,A'17UNS F'()R IIYURU(:RAPIIS li�'Shrrl I lnw f-qu:Mkm Ma�v�h�'�Valuns(f[x Ihn Initl�10(1 fl nl Iravri) n�• SI11fMN�1 9111IAfp!�CMN:IOIO.11l�lINli.(�laVpl�Of b111e ILlfd I111Ck�1��1I' O 0�1 , 1'nllow Ilclrlt nr hv�no r��rinr.e(�retklun� O 115 f:�AtHe�nl anM wNh�esklue tws�(� <�0.20 11/h) O OA I:�AIIvMn1 s�iN whh irzklue r.(wM(S�O 20 h/11) O I 7 SIM1��IITLI�1(�1059 IIIMI Ii1WIH � f1.IS`) I)enaelp�wsseo O TI 1 be��wKli grac� O�1 lianpo(nnluraQ O 11 W�Is nr Iroosi wl�h IIpM u.xle�lxush 0 40 WOqf)3 M�MR5)wMI1(IBf150 IMl[JP.fI)fUSII 0.8�1 ""_�""___'_""'_'_�_ y ____"—_' � _'__�_ .. _._. ' . _.'._ •Manr vnpipe Icw xho.M II(rw di Irom O.�Mon�nd Meedowf 1978 Ses TA-55, 19Af1 'k'Vehrxf Usrcl h�lrawd 1Mne/1NM d Ca�cerNrelbn Cwlcdallons Slwllrw.ConceMre�af FMw �Aher IM Inhlel�00 h.d�beM Ilow,N -0.1) M, - �---------------- --�----��-----.. I. Fwosl whh heavy pra�d IM�r�nd meadows(n-0.10) ---- - --- 1 2 fl�uehy q�onrd wHh sane Irse�(n-O.D60) 5 J F�nMow or mbikni�m tllspe cWllvallon(n -U Oa(1) A �� Illph prast(n � O.O,lS) ., � S Shrnl pres�,pnslure end Iswm(n-O.OJO� 8 Nsady hers prand(n-OA15) I J 7 Pw�cf url pr�vel nes�(n-0.012� 27 Cl�nnnal f Mw p�darrntnn�a)(A�Uro I�rpHx�Mq d visllas cliaonel� R.02) 4 1 f�xaslnf awaln wbli h�avy prwrrllNtm(n = O.tO� g 7 I�rNrtsIn11L1141:1(�11 f,01//lOIIIIVMIq WNM[�IIIIn11rI I:MMNIOI IIMI�n.0A50) 111 J Rntrw Ilncrl welr.rvvay(�-0075) IS � G�Ass�lwatnrway�n-OOJO) tl S Cnrtl�Ih�orl wntawny(n.00?5) 20 R CMP pl��e�n.0094) PI ! Conr,rNe�d(>9(01)17) 1? 8 Olher wato.wnye aiKl plpss , O.SOB/n Ghanncl Flow(Coni4n�ane elream,R �0.1) k� 9 Mr.��dednp slrenm wMh lonM poolf(n -0.040) 20 10 f1a-k llnal stream(n-00�5) 7J I I (3rase�llntxl sbeam(n-0.09f1) 2l 12. OU�or sl�eams.rtun-mede cl�snnele�nd plpe �po�/�•• , ----- -- -- — — - - ___. _ I ••See Cha�Mer 5.TaMe 5.9 6C lor addNbnM Manninp�'n'valuee lor opan channels — 2 � �.s.2-> >�► 1.30' CLEAR 5.44' CONTACT AREA 5.20' 3234 CF/FT TOTAL 36" OIA 6" SED 7' DlA = 84" DIA �,_ , _.� �,, � �� ,_ _ _ r , , �. ; � � ��7 GF/ ^ � 3Z. 3y c �/�r - 02. 5 /�f S� �'�� /�'Ii�' �Fr� r,cl �2� r� �H�2 cr��E r-�r�� - G . �I, z , Z , jj � L-�?►� �Ae� �e� PN � , � ' DE/�7/�, Z�G7�� ' ; � ti vy. 5 sF 2rQ��2c= �-� , �� 5 i N� �. y y x S 3 � _ �� /. � s F �`��; P� - z� V. CONVEYANCE SYSTEM ANALYSIS The proposed storm system consists of 12-inch pipe (double wall N-12 pipe) conveying runoff from the site. The 100-year developed runoff from the site was calculated to be 0.75 cfs. The 12-inch pipe proposed for this development is designed at a slope of at least 1.0% slope. The attached calculation determined that the proposed pipes at a minimum of 1.0 percent slope will carry 3.86 cfs, more than 0.75 cfs anticipated for 100-year flows for post development conditions. � I Pg. — 30 tmp#l.txt Manning Pipe Calculator Given Input Data: shape . . . . . . . . . . . . . . . . . . . . . . . . circular solving for . . . . . . . . . . . . . . . . . . . . . Flowrate Diameter . . . . . . . . . . . . . . . . . . . . . . . . 12.0000 in �epth . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.3000 in slope . . . . . . . . . . . . . . . . . . . . . . . . 0.0100 ft/ft Manning's n . . . . . . . . . . . . . . . . . . . . . 0.0120 Computed Results: Flowrate . . . . . . . . . . . . . . . . . . . . . . . . 4.1515 cfs Area . . . . . . . . . . . . . . . . . . . . . . . . . . 0.7854 ft2 wetted�Area . . . . . . . . . . . . . . . . . . . . . 0.7669 ft2 Wetted Perimeter . . . . . . . . . . . . . . . . 31.8447 in Perimeter . . . . . . . . . . . . . . . . . . . . . . . 37.6991 in velocity . . . . . . . . . . . . . . . . . . . . . 5.4131 fps Hydraulic Radius . . . . . . . . . . . . . . . . 3.4681 in Percent Full . . . . . . . . . . . . . . . . . . . . 94.1667 % Full flow Flowrate . . . . . . . . . . . . . . 3.8597 cfs Full flow velocity . . . . . . . . . . . . . . 4.9143 fps - Page — �� Vll. SPECIAL REPORT AND STUDIES GEOTECHNICAL REPORT-BY ICICLE CREEK ENGINEERS Pg. - 3� ICICLE CREEK ' E N G I N E E R 5 Geotechnical,Geologic and Environmental Services January 31, 2005 Keith Menges K&M Construction 1615 NE 28`�Street Kenton, Washington 98056 Report Geotechnical Consultation Roof llowi�spout and llriveway Slormwater Disposal Sandy Lane Plat 2142 Union Avenue NE King County Parcel No. 0323059041 Renton, Washington I ICE File No. 0488-002 IN'TRODUCTION This report summarizes Icicle Creek Engineers' (ICE's) geotechnical consultation regarding roof downspout and driveway stormwater disposal for four proposed,single-family lots at t}ie Sandy Lane Plat in Renton, Washington (King County Parcel No. 0323059041). Our services were completed in general accordance with our Confirnung Agreement dated January 18, 2005 and were authorized in writing by Keith Menges of K&M Constcuction on January 18, 2005. The project site is shown relative to i�earby pliysical features on the Vicinity Map, Figure 1. The proposed property layout is shown on the Site Plan, Figure 2. PROJECT DESCRIPTION We understaiid that this 0.93 acre property is being considered for residential development. 1'he proposed developinent plan divides the property into four separate lots, ranging in size fmm 0.17 to 0.3 acres. Each lot will be developed with a single-family, two-story, wood-frame house. The pmposed stormwater plan for these lots is to connect Lot 1 to the City of Renton's stormwater line on Union Ave NL', located about 500 fect west of the Lot 1 along a privale drivewny. We unclerstand th�t the remainitik three lots are located further east and down-gradient from Lot 1 and, as such, are not practical for gravity stonnwaler drainage. It is proposed that these three lots (Lots 2 through Lot 4) ulilize roof downspout drainage conUols such as stormwater infiltration, if feasible, or dispersion. Access to individual lots is proposed by improving the existing private driveway by widening a»d continuing lhe exi�ting asplmlt section, located at the entrance of the property. SCOPE OF SERVICES The purpose of our services included geotechnical consultation regarding roof downspout and driveway stormwater disposal. Specifically, services provided by ICE inc(uded: • A site visit to observe existing site conditions. � � • Observe the excavation of four test pits in the proposed infiltration arcas; Iconduct tw� 17e1d infiltration tests. �.� �7f� h�l �II"1lli�l `.ti��,,,1 �i�ill' �!'1 • �� i';'I . ' ��"'� �l",Il'�' ir��l • .,.... : �rl��nrlr:,��,.r��ilr�r-i�. �,,,� . � � � i � ,�<�� .'� i, • . ' � ` . "� � , . ��. . � . . ... Keith Menges K&M Construction January 31, 2005 Page 2 , • L'valuate tt�e soils in the infiltration areas regarding an estimated infiltration rate based on our site observations and the results of the infiltration tests. • Provide reco�nmendations for installation of a roof downspout infiltration system provided that the soil type(s)observed in the test pit are adequate for infiltration. SITE OI3SERVATIONS � 5URNACE CONUI'I'IONS On January 21, 2005, Colin Turnbull of ICE conducled a site visit to observe surf�ce conditions of the property, and to observe the excavation of test pits in the proposed infiltratiou areas (using a trackhoe provided and operated by K&M Construction). '1'he property is partially developed with a one-story single-family house and detached garage locateci on the east portion of the property, within an upland area, at about Elevation 445 feet. 7�he property is surrou�ided by existing single-family residential developments to tl�e north, east and south. "I'wo existing utility easement corridors (sewer and water) are located on eastern edge of t}�e property boundary and extend about 100 feet east to Vashon Avenue NE. A private driveway allows access from the west off Union Avenue NE. This private driveway to the properly generally slopes down to the wesl toward Union Avenue NE for the first 150 feet and is paved with asphalt. "I'he rest of the driveway is gravel-surfaced and continues east to the curcent existing residential structure. This portion of ttie properly slopes down to the east at a 2 to 3 percent grade. The properly is vegetated with occasional coniferous trees, grass and blackberry bushes. At tlie tilne of our site visit, no surface water, including springs and seepage, was observed. SUBSURFACE CONllIT10NS According to the regional mapping by the U.S. Geological Survey (E3ooth, D. B., I�augerud, R. A., and Sacket, J., 2002-Geologic Map of King County, Washington: scale 1:100,000)the project site is underlain by "till". The King County Soil Survey (1973) compiled by the U.S. Depariment of Agriculture Natural Resource Conservation Service (formerly the Soil Conservation Service) indicates t}�at the project site is underlain by two soil units of the Alderwood Series. I3oth these soil units are noted as having a very slow permeability below a depth of 24 to 40 inches. Subsurface conditions at the project site were explored by excavatit�g four test pits ou January 21, 2005, using a track-mounted excavator. 7�he test pits were logged by an engineering geologisl from 1CC. Soils were classified in accordance with the classification system described in Figure 3. 'I'he logs of the test pits are presented in Figure 4 and 5. Observations of the ground water conditions were made as the test pits were advanced. Test Yil 1'P-1 encountered shallow ground water at 1.G feet a�id was tenninated at 3 feet. 'I'est I'its TP-2 and 'I'I'-3 generally encountered similar subsurface conditions which consist oF a 7 to 14 inch surficial layer of topsoil underlain by weathered soil consisting of inedium dense silty sand with a trace of gravel and occasional cobbles to deplhs ranging from 2.5 to 3.0 feet below the ground surface. "l�he weathered soil is underlain by native soils (glacial till) consisting of dense silty sand with variable ainounls of gravel and occasional cobbles to the completion depth of the test pits at 5 feet belo�v the ground surface. Fill encountered in Test Pit TP-4 consists of about 4 inches of topsoil fill overlying medium dense silty sand with fine gravel and occasional fragments of glass from 4 to 13 inches below tt�e existing ground surface. This fill is likely the result of grading for t}�e present gravel-surfaced driveway. According to the 1998 King County Surface Water Design Manual (1998 KCSWI)M) (I�igure 5.4.1.A-USDA textural triangle)the soils encountered can be generally classified as"sandy loam". j Icicic Creek Engineers �; 04R8002/0 1 3 1 05 � Kcilh Menges K&M Construction January 31, 2005 I'age 3 Ground water was observed in all the test pits near the interface between the weathered soils and glacial till soils at depths ranging from 2.5 to 3.2 feet. Occasional perched layers occurred about 10- inches above this interface. FIF.LD INFILTRATION RATE'CESTING ANU ANAI,YSIS Field infiltration tests were attempted within each of the four test pits excavated at a deptli of about 2 feet. 'I'his depth roughly corresponds to where the weathered soil grades to glacial till soils. '1'hc field infilUation tests were conductcd in general accordance to EPA's ralling Iicad Pcrcolation '1'est procedures as referenced in the 1998 KCSWDM (Chapter 5.4.1 — Measured tnfiltration Rates, 'I'esting Yrocedure). Infiltration tests wore conducted by excavating the test pit down to 2 feet below the existii�g ground surface and then digging a 6-inch diameter test hole down an additional 18 inches. "I'he test hole was then filled with water and the rate of infiltration measured over time. "I'wo test pits (TP-1 and TP-4) encountered shallow ground water at the test depths, and as such, infiltration tests were not possible at these locations. The tested field infiltration rates in Test Pits T'P-2 and TP-3 ranged froin 1 to 2 inches per hour. CONCLUSIONS AND RECOMMENDATIONS We have reviewed standard methods for disposal of roof downspout draina�ge using the 1998 KCSWllM (Seclio�i 4.5.1 Roof Downspout Infiltration Systems, and Sectio�i 4.5.6 Dispersion of Roof Runoffl. Based o�i our observations of the soil conditions in the test pits, tl�e soils that underlie tl�e area contain appreciable amounts of fines (soil particles classified as "silt or clay"- soil particles passing the U.S. Standard No. 200 sieve) and have too low of an infiltration rate necessary for standard infiltration design. We recommend that the roof downspouts be connected to the City's stormwater disposal system located in Vashon Avenue NE by utilizing existing utility easement corridors. However, we understand I that this may not be praclica( because of easement provisions. We are providing this recommendation to tie-in with the City stonmvater system, because this is the method of on-site stormwater ciisposal that sl�ould be used to reduce the potential for future problems associated with adverse ntnoff itnpacis to properties down-gradient of the proposed development. As an alternative method of roof downspout drainage cotitrol, we suggest dispersion at the ends of each downspout using splash blocks, possibly connected to downspout dispersion iretic}ics. Spl�sli blocks may be used for downspout discharging to a vegetated 1lowpath at least SO feet in length as measured from tlie downspout to lhe downstream property line. The length of downspout dispersio» trenches are detennined by the size of the roof area, which is outlined i�i the 1998 KCSWDM. Uispersion of runoff anticipated from driveways is recommended. The ground surface should be sloped away from building foundation areas. This may result in water ponding in the yard area during wet weather. If this type of syste�n is used, then monitoring of the effectiveness of surface water dis�iersion should Ue conducted. We reconunend that tlie roof downspouts be connected to the street stormwater disposal system if the surface water dispersion �nethod is not effective in cantrolling the roof dow�ispout drainage. � Por paved driveways we recommend, to the extent feasible, that runoff is dispersed to the same ' standards as roadways to ensure adequate water quality protection of downstream resources. Driveways ' should be designed to minimize collection and concentration of runoff. Dispersion trenches should be , designed to accept surface flows and protected to avoid soil erosion using standard best management � practices. CM Icicle C"reck [ingineers 04RROQ2/013105 ' Kcith Mcngcs I', K&M Conslructicm January 31, 2005 Pagc 4 USL+' OI� TIIIS REPOR'I' We have prepared this report for use by K&M Construction. 7�hc data and report should be ' provided to prospective contractors for their bidding or estimating purposes, but our report, conclusions and interpretatioiis should not be construed as a wananty of the subsurface conditions. i If there are changes in the grades, locations, configurations or types of developmcnt planned, the ' conclusions and recommendations presented in this report may not be applicable. If desigii cha�iges are tnade, we request lhal we bc given the opportunity to review our conclusions and recom�nendations and to provide a written modification or verification. When the design has been Gnalized, we recommencl that the final desi�i and specifications be reviewed by our finn to see that our recommendations have been interpreted and implemented as intended. "There are possible variations in subsurface conditions between the exploratians and also with time. A contingency for unexpected conditions should be included in the budget and schedule. Sufficient monitoring, testing and consultation by our firm should be provided during construction t�� evaluate whether the conditions encountered are consistent with those indicated by the explorations, t� provide recommendations for design changes should the conditions revealed during the work differ fro►1� those anticipated, and to evaluate whether or not eattliwork and foundation installation activities cotnply with contract plans and specifications. Within the limitations of scope, schedule and budget, our services have been executed in accordance with geiierally accepted practices in this area at the time the report was prepared. Nc� warranties or other conditions, express or implied, should be understood. ******************** We trust tlus letter meets your�resent needs. Please call if you have any questions. l �� i�� "'��//� / ��n r'� � Yours very truly� � 4 \ �() \ �a r �'-� �,,��.;�r;`.*�` �� Icicle Creek f:tigineers, liic. � � f '"� T j` ��•�.;, ,., -�' �;�s': , '� � � � r' .'��:Y'�. ,� _,r, � � ,C ' ,-�F�nrino�.;^��I'��.iisl,i� � / 1 � � �, E � J � �• ^D�'n� � '� '��,_ ��' � `�� ' 3a0 ��y �P� �'-''--�'"� .�',;�i` Colin 13. 7�un�bull. I:.G. �°ij �p� S�'�f (=�t'`' - sed Geo ; _ �__. ,____ Project Ge�>Ic�gist 'zfllil�'J ;i ��; � �,- :,�.f �_ �� Colir� B Turnbull ��,:: �` �� - �� _ ----- , ; . �., .,i,'��i �.-. i � � �_ �. �., r'4 -r, /f f ` -' `"i ' l��r� r' � ' ; I3rian R. Beaman, P.E., L.(�. rn ,�_ � � �=''�� , � Principal Engineer/Geolo�ist . � ��:, Uocume�it ID: 0488002.REP '7� 2,��i�, ,�� 7'wo co ies submitted _p�'��ISTF.��`.�" �` V S --- <<, ;, �'In�i;;. . p•-T-; . � " ....��_��.� _i o� r-y�.-.F, i I � . _ . � 0 � � � a.. � r . � �. ,yy n j t�1 ., , : � 1 �--- � f . i.� .`� •, o "Y r B -.,+►� i: ' r� �.;i��t 4Y- �. 4S' � �� 9� �.\ 1. . .. 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' `y � ._� , I� l � T �, 4u�"T��T' y._ �. -^ � '-�. i � � �~� . �+ �..� f�� -'�G...:.....�.Yy..,..T' "' - :'. � - " x� Y F �Y��:,� � t� �F .A-...�- `L�S:.�y�rt—�-i.�, -�..'".�.-,. h�'•. �µ .''�� -.�.� � 1 � _ ..r�_..�A... � � �l• .. � 'f4.�` `1 -�. ,. � y .. r . � - �.i.F� -'S��. - y++ - ` •_� �,Tr � ' ' N . � Y Y'i./ .�� T��.^ _j• uy �� S � ,� � �;_ - '�� .{�. _� :t ..� � p� .� ��~ �T"" -� �i�.� '�'��. �� -_ _, - '- � ... _ �',�, '' 4 r -�� i � w .� ��. � �_ {�� - Lof 2 � - Lot 3 � � I! � ._` .'� �'�� 4 � Tt-�-� I ofii a`+,..�- --„'.-�'-- �-ur� ..�� _ + - . �" � a �'�°c�'� .� �aq"- i r^'s E+�3"� � Q' r i . � 17 i:_ uK T:^. .` �S �' ��-4 J .' _ . _ . i„� t' :.t'_i .4"�#".�.;. .'+�� ,�. • :/n..�. .'�.C. � •° , : - - .. ,* : Lot 1 ��=r � _ {�: . �_, j J �-�� -a*.� �.��y�� ,..�.�; �� ,:�� - �.>:.. . '_ � ;,c.i4,,�� .�.t i �i� � }� x ,. , r .. �•� .�ffi;r`�':-G; ' r�;, �,;:'�'- � �.� �r��t t�",,j, �, ,�: ��,_ LOt 4 Approximate Location of - , =-u�=-* ��'.A'� ��{��' C .��' ��:��_ •' X: - Existing Development . ... .- _.: _ ,•. � .�:,:�.:�,��" . _�. '� • � Driveway _ . '" . , " .,.` � . , ,-�. _ _ { � i .�, r^ . '� .��y f ,,' � . ��. ri. �r., � �: � .� � ' ,�+y,{� • r __ ,�.,..k • -?��' ,.A:.,,.,.... =� ; �+ .4 �- ., � � ' t� ..��.' :� � �� -� Sandy Lane Plat �`-- .., �.� � � ,� � Property Boundary ��. :'+�jt""'�i �a �,w T . _ .� .�. �`"� , - . � - ...y�.+z,..�.• C `�"`�j��.;.. •r��•� ::.� _*��r��' � � Y _� .�` y_. ; , �r. ' _ �. � �. ,P � _ . " � y�„s YR*'*� �`".1'{a..,� ��T ..a,. Y. �._ �O .., �� ..*a..:: �.. � �_._ R.....� d~� � �� :.'#�-� L."t.��'..a..1s��_ �. .� .. . �Q .� � Aeriai photograph taken from Interactive MAPping(IMAP) King County(http://www.metrokc.gov/gis), dated 2002. 0 60 �2o Expianation: Approximate Scale in Feet �TP-1 Test Pit Location . ' Icicle Creek En ineers Site Plan - Figure 2 f CLIENT K8M Construction PROJECT NAME Geotechical Consultation PROJECT NUMBER 0488-002 PROJECT LOCATION Sandv Lane. 2142 Union Ave NE. Renton UNIFIED SOIL CLASSIFICATION SYSTEM MAJOR OIVIS�ONS SYMBOLS TYPICAL DESCRIPTIONS wELL�(iRADF.D GMVEl9,GRAVEL�9AND Mx1URF4. CLEAN GRAVELS GW UTi�E O(7 NO FINES A�OftE THAN 50"h pF (L�TTIE OR NO Flf�S) GP Poor+�Y cw�oeo��a.du��.sN+o Mx.�s. Sofl Particle Size Definitions COl�FSE FR/�CTION UTfIE OR NO FINES REiAINEO ON NO� GRAVELS WITH GM �Ty pp�yE�9.GMVEL�S�W-Slli MMURFS Com nent Slze Ra COARSE SiEVE F/NES � � GRAINED SOILS (ApPRECIABIE MADUNTOFFWES) GC �`��'��5.cw�vF��su�m-cuvrwxn�aFs BouklCrS C08r5CfthAnl2inch MORE THAN 5076 OF S.W wELLGR�DEO5AND5,L1TT�E OR NO FINE9 C�V� 3 InCh 10 12 inCh nenTERw�is CLEAN SANOS LARGER THAN NO. (LITiLE OR NO FINE3) Gravel 3 Inch t0 NO.4(4.78 mm) �oo s�vE S�zE MpRE THAN 5036 OF gp P�x��D SNA9.LITiLE OR NO FINES Coarse 3 inch to 3l4 inch COARSE FfY�CTION gqNDS WITH P/445�H0 NO.1 SIEVE gM m�r ywo�.y�.b.e��T r.�Mu�e Fine 3/4 inch to No.4(4.78 mm) F/NES Sa�d No.4(4.78 mrp)lo No.200 (AFPRECINBLE `� CUVEv SANDS,S�NO-CIAY MXTURE9 (0.074mm) MAOUMT OF FlNES) ML SILiYORQAYEVFINE9ANU8ORCUVEYSRT$WIT1 �� 4I4.78mm)toNo. 10 suc,�+T vusnan (2.0 mm� SILTSAND uouiou►ar�ess Y Medium No. 10 2.Omm toNo.40 FlNE GRAlNED C�ys tww so CL �S LLV CUIYS.SA/AV QAYS.SILTV CIAVS.LEAN (0.42 mm) 1 SOILS ortcnrac sars nw oac�,�u�c s��rr cuvs oF�ow � c�asncan Fine No.40(0.42 mm)lo No.200 MORETHANSO9GOF MH INpR6AMC51LiS,MGCEWSORpA10AMCEW9F�NE (0.074mm) nMTERIAI IS snwr oa s��rv sa�s.eusr�c aits SiM and pay Finer ihan No.200(0.074 mm) SMALLER THAN NO. SILTS ANO L�OU�O LMAT 200 SIEVE SI2E C�ys GREATER THAN SO CH ��MC dAv9 oc HOH vuSTld7v ORGAMCCUII�OFMEpWTO/MHi'U1911C1iV, MOIS�UrB COntBnt� � OR('aAMC SILT9 � HIGHLY ORGANlC SOlLS pT �r,�nnwis.swa.v sa�s v�nrH ixcH oac�vnc carterrrs Dry Absence of moisture NOTESI)Dual symbols are used to Indicate gravels or sand wlfh 5-129'e flnes end aolls with Ifnes claaslfying as CL-ML. Mast Damp bul no visible water 2►Symbols separaled by a dash indicate baderFne soil Gassifications. Wet Visible water 3)The Nnes separatin soii t on the logs represents epproximate boundaries ony.The adual boundaries may vary a 9be gra�al 4)Soil Classficafion based on visuat�lassification of soil is based on ASTM D2488-90. 5)So�l Classification using laboratory Iests is based on ASTM D2487-90. 6)Descriplion of soil density or cons�stency is based on interpretalion of bbw count data and/a lesl data. Sampler and Gu�er Sy�nbol Desc,ipiio:.� ^^�� ''�� ^��+P�� G� Location of Grab Sample Flne-Gral�ed Soils Q Approximate depth of perched water or ground water very Soft Easiy penetra�ed several Inches by nst Soft Easily penetrated several inches by thumb � F�� Medium Stifl Penetrated by thumb wilh eHort Stifl Indenled by thumb with effort Asphalt Very SIiR Indented by Ihumbnail Hard Indented with difFicufly with thumbnail NOTE: The depths on the test pit logs are shown in 0.1 foot increments, however these depths are based on approximate measurements across the length o(the test pit and should be considered accurate to 0.5 foot.The depths are relative to the adjacent ground surface. � 0 � � O � W U 2 (7 N O O m T a 0 u N F a � � w � � Icicle Creek Engineers 9« Explanantion For Test f'it Lo�s - Figure 3 Test Pit TP-1 CUENT K&M Construction PROJECT NAME Geotechical Consultation PROJECT NUMBER 0488-002 PROJECT LOCATION _Sandy Lane, 2142 Union Ave NE, Renton DATE EXCAVATED 1/21/05 T�TAL DEPTH 3.0 ft GROUND ELEVATION 445 fl(approx.) LOGGED BY CBT EXCAVATION CONTRACTOR K8M Construction WATER LEVEL 1.6 ft/Elev 443.4 k� CHECKED BY BRB EXCAVATION EQUIPMENT Kubota U35-Trackhoe NOTES Lot 2 and Lot 4 w _ ° `_' ao �� '"� =U' � W (n w� MATERIAL DESCRIPTION �� Q p �O� �� F REMARKS o W ; c�; Q Z g o `� Dark brown SILT with a trace of sand and aburxfant roots ML 0•e ve soft moist to soil �•4 ��-�+ Light brown silty fine to medium SAND with a trace o(gravel and occasional cobbles -_�� (medium dense,wet) (weathered soil) S —"�� __:o_ SM o-.-� - -o- --e._' 3.0 442.0 —�� Rapid ground water seepage encountered at 1.6 feet from all sides. Moderate caving from sidewalis. Test-Pit TP-2 I CLIENT K&M Construction PROJEC7 NAME Geotechical Consultation PROJECT NUMBER 0488-002 PROJECT LOCATION Sandv Lane.2142 Union Ave NE, Renton OATE EXCAVATED 1/21l05 TOTAL DEPTH 5.0 ft GROUND ELEVATION 445 ft(approx.) LOGGED BY CBT EXCAVATION CONTRACTOR KB�M Construction WATER I.EVEI 2.5 ft/Elev 442.5 ft Q. CHECKED BY BRB EXCAVATION EQUIPMENT Kubota U35-Trackhoe NOTES Lot 2 � w � Z v J a� � _ � a0 �w cn W� MATERIAL DESCRIPTION a� a p �g �� REMARKS a � �v � �� QZ g Q � Dark brown SILT wilh a trace of sand and abundant roots — ML 0.6 �e soft moist to soil �•4 - Light brown silty fine to medium SAND wilh a trace of gravel and occasional - cobbles n (medium dense,moist) (weathered soil) -"��' SM 1 0 o a 'Infillration Test � 2.5 442.5 ::-_ : � Gray silty fine to medium SAND with a trace of gravel and occasional cobble � (dense,wet) (glacial till) "=�"c w _t�.. � .-_o. SM a o 0 C9 0 � N - O ,n 5 5.0 440.0�_°_ g 'Infiltration test(IT-1)conducted at 2 feet-result<2 inches/hour. � u N X a � w U Icicle Creek Engineers � � Test Pit Logs - Figure 4 .' . Test Pit TP-3 ClIEN7 K&M Construction PROJECT NAME Geotechical Consultalion PROJECT NUMBER 0488-002 PROJECT LOCATION Sandy Lane,2142 Union Ave NE. Renlon DATE EXCAVATED 1/21/05 TOTAL DEPTH 5.0 ft GROUND ELEVATION 445 ft(approx.) LOGGED BY CBT EXCAVATION CONTRACTOR K8M Constructlon WATER LEVEL 2.3 ft/Elev 442.7 ft Q CHECKED BY BRB EXCAVATION EQUIPMENT Kubota U35-Trackhoe NOTES Lot 3 w = O = a0 �w v~i w� MATERIAL DESCRIPTION �� Q O �� ►w-- REMARKS � w � c,`�" QZ g o `� Dark brown SILT with a trace of sand and abundant roots (very soft,moisl) (topsoil) c�+, ML 1.2 443.8 Light brovm silty fine to medium SAND wilh a trace of gravel end occasional -- cobbles --�o (medium dense,moisl) (wealhered soil) Q _-ti- SM 'Infillration Tesl —�- v- — 3.0 442.0"��" Gray silty fine to medium SAND wifh a trace of gravel =� - (dense,wet) (glacial till) "�o- -� - SM ---� -?_�- 1 5 5.0 440A :-=- 'Infiltralion test(IT-2)conducled at 2 feet-result<1 i�chlhour. Test Pit TP-4 CLIENT K&M Construction PROJECT NAME Geotechical Consultation PROJECT NUMBER 0488-002 PROJECT LOCATION n La 14 ni n Av NE Renton DATE EXCAVATED 1121/05 TOTAL DEPTH 5.0 ft GROUND ELEVATION 445 fl(approx.) LOGGED BY CBT EXCAVATION CONTRACTOR K8M Construction WATER LEVEL 2.4 ft/Elev 442.6 ft Q CHECKED BY BRB EXCAVATION EQUIPMENT Kubota U35-Trackhoe NOTES Lot 4 w Z U � a� � _ a� MATERIAL DESCRIPTION Q� C9 �O w cn w., ]� �O �g �g i-W- REMARKS o w � �� aZ g o �' Dark brown SILT with a trace of sand and abundant roots 444 7 ve soft moist to soil fill SM �,� Light gray silty fine SAND with a trace of gravei and a trace of glass 4q3.g ' fragments =-- medium dense wet fill -.�n o Light brown silty fine to medium SAND with a trace of gravel and occasional -�-' SM � cobbies SZ _=o_ (medium dense,wet) (weathered soil) °-o- 0 3.2 441.8 =• W Gray silty fine to medium SAND with a trace of gravel and occasional cobble � (dense,wetJ (glacial till) -�e a' -ii". SM I � - - N " "O. m 5 S.0 YYO.� O O g Rapid ground water seepage encountered at 2.4 feet(rom west sid�of the � test pil. n � w U Icicle Creek Engineers ,1,, Test Pit Logs - Figure 5 . . VII. BAS1N AND OTHER COM�VIUNITY AREt�S - N/A II VIII. OTHER PERMITS - N/A Pg. - 3� . IX EROSION & SEDIMENTATION CONTROL The contractor shall install silt fences along the perimeter of the site as indicated on the Temporary Erosion Sedimentation Control Plan, with construction entrance 12" thick made of quarry spalls as indicated on the construction plans. The temporary erosion plan will be designed to the requirements of the 1990 King County Surface Water Design Manual. The silt fence and silt trap are placed to help reduce the chances that any construction related silty runoffwill leave the site and affect downstream facilities. The , amount of cleared area for road and site construction will be similar to the 2-year developed peak, which will produce a peak flow of about 0.30 cfs. From section 5.4.5.l of the 1990 Erosion and Sediment Control Standards a sediment trap for less than 3 acres development should contain a minimum surface area at 3.5' depth to allow settling of the silt particles. The minimum surface area is to based on the formula; SA= FS (Q2/VS) where FS = Safety Factor= 2.0 Q2 = Peak 2-year developed flow (0.30 CFS) V2 =Particle settling velocity=0.00096 f/s SA= (2) (0.30)/(0.00096) =625 SF. Required 3:1 side slopes 240.5 0'x15' bottom 241 3' x 18' 242 9' x 24' 243 15' x 30' 244 21' x 36' SF at 3.5' deep 756 SF overflow el. 245 27' x 42' top of berm The sediment trap should be constructed on the lower portions of the site. Pg. - 3�'