Loading...
HomeMy WebLinkAboutSWP272723(1) Technical Information Report < -�v - 2;— 2,�2_? Glacier Creek Renton, Washington 9718 Prepared for: Kent Angier Buchan Properties 2821 Northrup Way Suite 250 Bellevue, Washington 98004 (425) 827-2266 Prepared by: Pacific Engineering Design, Inc. 130 Andover Park East, Suite 300 Seattle, Washington 98188 (206) 431-7970 (206) 431-7975 fax 0 1 J_ 12 O February 19, 1998 own�tSIER _y � _2�jv - �l PR 4 �g9 qua s w 1 rLc � i 1 Technical Information Report Glacier Creek Renton, Washington 9718 Prepared for: Kent Angier Buchan Properties 2821 Northrup Way Suite 250 Bellevue, Washington 98004 (425) 827-2266 Prepared by: Pacific Engineering Design, Inc. g g g 130 Andover Park East, Suite 300 Seattle, Washington 98188 (206) 431-7970 (206) 431-7975 fax t8 22 February 19, 1998 tONAL kz- Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET Project Owner ►3 yG►in,) �'t n�• .z r :S Project Name G�hL r"z G c / T n Esc=> 141-2 Addross ZBZ� nG2 �2u(' %--A-i � Z5o Location Phone r"'Lrv(-4-` '^/A Ssro04 Zt66 Township 23 Project Engineer (S► ,r_ G+rZ i 1-► Range ';-Q Company (2AL1r-)L f=nl,inCr,,40f. S)L,cI ►rlC- Section 31 Address Phone 130 A1,12OV&I �',r. r '4 30o Project Size 12.2 AC ATTL� t."A. 01f1$� 206-d 0 Upstream Drainage Basin Size 6G-70i AC F-1 Subdivision DOF/G HPA Shoreline Management 0 Short Subdivision n COF 404 Rockery LJ Grading DOE Dam Safety ® Structural Vaults ® Commercial (D FEMA Floodplain 0 Other 0 Other 0 COE Wetlands ( HPA Community Drainage Basin S(72irl1n(i2a.i(, Q River Floodplain ('Stream CLnSS 3 �Twn 6xS)n A-+(3 Wetlands (sin / LD) ( JJ ► rZ9T cr` ® Critical Stream Reach �P2�ny�3,zaa�L - C] Seeps/Springs r'� �` ��r= "r ���c `� S rm. Depressions/Swales LL�'SS Z 0 High Groundwater Table C7 Lake Groundwater Recharge Steep Slopes ED Other Lakeside/Erosion Hazard Milk iiaq Soil Type Slopes Erosion Potential Erosive Velocities ^ A Fcz Q�yrloP6r7 Cl Additional Sheets Attatched 1/90 Page 2 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET • • REFERENCE LIMITATION/SITE CONSTRAINT Q Ch.4-Downstream Analysis _ Sir 4n-, G rC ash)n — Q A,�S a a a 0 Q Additional Sheets Attatched MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION Q Sodimontation Facilitios Slabilizo Exposod Surface L�J Stabilized Construction Entrance Q Remove and Restore Temporary ESC Facilities Perimeter Runoff Control Cie an and Remove All Silt and Debris ® Clearing and Grading Restrictions Ensure Operation of Permanent Facilities M Cover Practices Q Flag Limits of NGPES I� Construction Sequence Q Other 0 Other Grass Lined Channel Tank Infiltration Method If Analysis Pipe System �' Vault/L,r-T Q Depression �rJo� Q Open Channel Q Energy Dissapator Flow Dispersal Compensation/Mitigation 0 Dry Pond Wetland Waiver of Eliminated Site Storage 0 Wet Pond Stream Q Regional Detention nrr'✓f Brief Description of System Operation 2vnor•-r- FYz0.0, Or_Z V r'44W6F ;. -tO -ry 11r Vr1.L S(7rtr A,-,�r--f Facility Related Site Limitations Reference Facility Umitation 0 Additional Sheets Attatched 0 Drainage Easement (� Cast in Place Vault Q Other Q Access Easement Retaining Wall Q Native Growth Protection Easement l Rockery>4'High Q Tract 0 Structural on Steep Slope Q Other I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the J�------� attatchments. To the best of my knowledge the information provided here Is accurate. srg .�. 1190 r 1 TABLE OF CONTENTS PAGE PROJECT OVERVIEW . . . . . . . . . . . . . . . . II . PRELIMINARY CONDITIONS SUMMARY . . . . . . . . . III . OFF SITE ANALYSIS . . . . . . . . . . . . . . . . IV. RETENTION/DETENTION ANALYSIS . . . . . . . . . . V . CONVEYANCE SYSTEMS ANALYSIS . . . . . . . . . . . VI . SPECIAL REPORTS AND STUDIES . . . . . . . . . . . VII . BASIN AND COMMUNITY PLANNING AREAS . . . . . . . VIII . OTHER PERMITS . . . . . . . . . . . . . . . IX. EROSION/SEDIMENTATION CONTROL DESIGN . . . . . . X. BOND QUANTITY WORK SHEET, RETENTION/DETENTION FACILITY SUMMARY SHEET AND SKETCH, AND DECLARATION OF COVENANT . . . . . . . . . . . . . XI . MAINTENANCE AND OPERATIONS MANUAL . . . . . . . . r I. Project Overview This site is located at the northwest corner of Talbot Road South and South 55th Street in 1 Renton Washington. The easterly property line abuts Talbot Road South and the southerly property line abuts South 55th Street. Total site area is approximately 47.0 acres. Developed site area is approximately 12.2 acres. The site slopes down from the east to west with an average slope of 6.5 percent. There are no existing structures on-site and the site is heavily vegetated with various trees and understory. The site is to be developed into a 160 unit multi-family project. There will be a total of 32 apartment buildings and 1 recreation building. There will be 10 buildings that are 2 story flats and 22 buildings will be 2 story Townhomes. . ■L+ _�;5�— , _` sE InM -at;E3 .X�,Y I a.M�aa n - -� sr n 5 1;3'x a ITSkY � f y�+F. jCn'• I ` _ PA.Hf 2 RIDE ST $4DR0 SE�1q�i'(rt �M=,9orN I' sE ITN ST SE ISOTH T r py SE ]BOTH sr > I K �. Y ,� - ►-9:. ST CA ^' 1 e N, > W S ,= y�R i tt f Q SE- 1B2N0' SE ST <� E(�"182NO. N slsT n --- 181ST ST I<� sr ` • 1 51... E1��V MILLI I TM ' SE Ia3R0 W = Q �3 r S[seen 3i �a •.s � :� ♦` f�::.. BILE) i 31 I 32 sE �, vL m 33 :_t sr/ y' _at SE _ SE 784TH" 5T MrN �Jr5 1B3R0 SE lBRM pL Sr Sl.' $ O!s I JP jl SE E IB6TH ST SE IB6TN ST ,SOIM.EYst r/�.tt M M tMrN T u p < 34 18F N pL SF "z_f ! LANE J �'s k s, t F-f't IecrN it X - u lerrx < :• �r g S 1l7Tx ST srI!tt ::,i �'OTe Try li ^y >,'X"' o+s = SE 187TN ST S IBBix ST I - ul�s & _ 1 Cr IBBTN > T per'®TM"R` 1 r�� t�r�'"' SE pE - SE 188TH ST J,II1•= �'f u Ie1rN sr �vl "•a um < �i u ta, t:'l ^�rh� �' SE IB8M P +f `"7 S 190TH_ST 19orx s 90Tx- SY Q oM n d d rc z ^I` sl L%h n _ ■ sE Y it SE T ST I L 19orN w �I a�a 'iR N$ � ` ,75 Y T23N N T _ L ar E �' 192N0`'~ ST I-1 rol r p a• -�` SE T < ---N -- I cn �� I .h�M $ yl ,m 124M../.,, PARKS sE LL93RD ' "D SW 194TH 9 ' - SE TM v< �\ u 1 > ysM =_ _ tt a r"" <•z+'0. �i I LAKf :'"r :r 1 SE `4s t+• a��yri: r'OUM'SP'� 1%M t -S : LSd sr s 196TH _ST_ - _ 9Er 9 r SE 1 TH ST a y i��61RYa SE 4 At S '� �sxM s}sETM N $ 1 TH ST Is9� l awl i , ^' 7six ST SE PC KN PL m 197TN vl ^t Si 6N�2Lf E Y••SF 19)IN;Q 11M y 19 t� ^' S 4,� SE 197M EN T s�198TH 5T Nr 7--I 3 •<� < tt - ti y+ - .. 2>tir h a �1a 1995 I '€ XC SE=19BiH ST \` sF 19eM sr 3y= v u tN y.. � _ s N ZWTH ST �{ ;I N! S 200TH S� -- ST , I 4 ^ I ;I 1 sti • 5 TM �� t'+ a `�''~' `�' _ W 2 sFl �1 I ;N 3 ° N H u mssr> u u u SESE N 2015 ST e [J W NI ;1 { S 202W$T s > s > < l .. p v 202 $T pp o . '< SE 202 IN F , ,:3 = ,Wn 3'W 4 203RD ST A 3 g g ��� SE 207PD G514 m'>fo �r.7o'F PARK ,�` 'W^ t="' •<• gym' SE 201 H STEk' S 2WTH PL s I zatN \ a < f Mh tOSMr P k "�• fir' N >a� :M y h �, al _ FV' '.1 < i TN L co 'T=,7JS s_2O6t gg"'< nev7n[Reh "^ ' MAY PzonN SE. < v y ST m; $'� i ' rN a I = o SE i M K, IAFE 3&tn StN��}�-l�1- i ?far `%r 39-iv lama j% ,•,�:S[Zw _ 2, l+ c s sE to7 u zoitN CExrER sF r'=i?�,} �" KENTRIOGE DNS l0 Sr Ir' 'c ,. S 209TN I� 'S 209 1 SE B d 208TH - r"E'°n• ST - -' - :: 2M $E '� Y 2 TH SE 208n1 ST M @x Y LOB00 a SE TN^ ISE - -- 4 It gSS .L max, _I ST yr 76>< `3T z.. 2 =I s < i,W� a`svr = D +.a tt Tn < SI OTN ,fj,vlor yl`•N'. fiAMh 5 3 210TH ST ` K a ..11 tt zarN W SL oh < $_ ry 31OrIE SE 211M ST d' 4.. u SE 210TM K sE 21 N K1"i.t11M STI�^%N fs n rzr9 sF fit.'< n Q _ v I Y •'R i 212TH ST S /N SE ZIZTH ST 5 t9 w <:kh X 2117N ct t _sE_t TN ,"•}l (t s z1Srn IT 8 t7�rN T SE sr" S _ `! n+" • am sT SE—ST SE SE 212TH c lY"Din �Wf"h 3 tt i171N ST PE SE I :7 x S 21 S2urN nJ;ti�`a%T rTj�� S �r M sY' � �s�`s � '+ ----7•s*rh_ 7 2' I� n�� '".: - I ._ `ri = r ` :.I zuM ST �r e.- =It 8 � &N y�s turn � 2, ``ae�OpYQgp� = iC«'- nn u t rM n �^''r LL $E 217TN ST I +-... o al8,1' .no. -i` Fs 8 - _ gE 21 sr N9 9s`'ryror RafCc ,rtx w G l6TH K -= SE 216TH IoT SE WIN`yltsc 1c SE PMK 1- 2161H Sig i� SE �1 211�TMo IST �.f Y �` Y : sr ' 11 .• ' e.- s< :uM sr y Sr uzoo (2 w N 2181H SE 219 v� h SE IBTH SE 218TN `o g' p St I $E 218TH v Z n I CRFE = SE x `o N; +Q a s0 M1Cj SF Its N r PL <> I 6 s AV PK r+ 'y' 2l9 ' a<+h T 5= M S s '< SE 22(ITHST { sLL,,yy 10000 .. rn'r . sf : 220M K y "t y, a'~d s %M ^v' a - - SE 221 z=' PL G 222NO ST S Q a e saraE71 es KT E 57 k `S1 ure SE sc > 22\� $E 222ND ST H 6 1 222N004 a - —-- r -. 8 A msru F 223RD- _ST4A'o ' SE 224TH STsu 224TH I ST <.. <I Fl 1 -- SE 225TN tE''• r a v mr.=a ?� ' '1 lT m 226 M PL '� I a� g��.•• ' ' SE 27 ST mN s 228 ST - $IZBTH I <> ST- -_" SE 227TH P< t 7 t t;,`" xy 1' N -—I $T< I } t ain i jARX ^>r. - its P All , lgbL�r"1 F nt e m• TfigW CREEK.',;,� 7 i C 229TN P � "'y` 231SrS' PLN s y rT �'^�r E i715)32 �� t __ Sj -P u ,F, w 270Tx> STy( p 23IST ST r p t -? € SE 2315T< I S 232 ST 8 '^d S~ I I,2, <<,• 17 [J�' + ' u 3ST PL C` •� 16,E nst' ulo Jf N ' ? 7r {:15 r•>.� ",gm RIDGE RD SE 232ND PL NOPAK LN I 232 s iJ2r0 ., r =SE 32W s ST SE 27 1 e - 1 sn +, \ . SE 23M ST nRl7rtr -SE', 233RD Sr a.'_ 91M CT S g /ARK O iIR _�a?� � �<�.A'I tt f3790K •,y - _s v n z n s• sEE 716 wP --n W r cz=) T/// •���� // /� � 11 � � I'll \ � `� \ `\\ \\ \ ' \` \ ' \ �� I I �� LV\ f lV\ 1 k II I j., I, EV SITE PLAN I JL .0" red hi It �._r/ •\.\`\\.,.\.it 3 i I � 1 � 11 1 1 ' l \ ,\ ,` � �'ti � i� ` .7'� ��� ,t4�\,`t ,1 l k N, I 1,1 r I It I I Ii 7 'xf \k wl Ir '71 ;1 1 i' 1 1` •` '`? t � + 't ` } \ � } 1. �`;5•� 1 � \ �1 �• � L { , 1 � `' I 11j'.� �' 1 ,1i 1 i '\ ',! 1, , ' \\ , `\ \•` t t 41', �}ev"ttP, \ `` ; t •t; R '�� 1, �` ,1 ri , ` ��I It . I V f-I V'\`\ t\\,`i - 15 !'} �! tL \\ \ .•\} \\\ �}�\.. ;\\,. \��\ 'Nor 1.19C 40 &*Vl Ir �.�F+r 1.\Q }? ji ` � + 1 t i � � � f � \ � } ` t �� ` �t 1? \\I\\i``\• \ ; ty t \1t\�\` l`,� �i\�( .40--14i it % -,/ T 1 4, ;e T 6L WIG, L— 'b low 4. qril! i it K, St IN rc�4% rl ,I lit -jW err (my'r r�Ar —17 Ile, ke at t4 S.55th.St .1e f , . II. Preliminary Conditions Summary The project was submitted for Preliminary approval on or about August 18, 1997. The Mitigated Determination of Non Significance (no date) and Hearings Examiners report (dated November 20, 1997) is included in this section. The USGS topography map, wetlands map and stream map are included in this section. P'J_ 0,-T -- - 1� CITY OF RENTON DETERMINATION OF NON-SIGNIFICANCE (MITIGATED) MITIGATION MEASURES APPLICATION NO(S): LUA-97-119,SA-H,ECF APPLICANT: S.E.B. Inc., Eric Blitz PROJECT NAME: Glacier Creek Residential Development DESCRIPTION OF PROPOSAL: Proposal for a 160 unit multi-family development, with half of the units proposed as townhomes and the other half as apartment flats. The development area would be limited to the east 13 acres of the 47 acre parcel in order to avoid a large wetland area. The proposed dcvcloprnent would be accrS Bd off Talbot i?osd S. and off S. 515th Street. A total of 382 parking spaces are provided, which equates to a ratio of 2.39 parking spaces per unit. The code requires 1.5 parking spaces per unit with one space per 4 units for guest parking, equating to 280 parking spaces. The proposal includes 128 parking spaces in garages, 56 spaces in carports and 198 open parking stalls . LOCATION OF PROPOSAL' NW comer of Talbot Road S. and S. 55th Street MITIGATION MEA§Qn8: „ 1. The applicant shall pay the appropdate'Fire Mitigation Fee equal to $388 per multi- family unit and $0.52 per square foot for the recreation building: The fee for the residential units Is estimated at approximately $62,080. The Fire Mitigation Fee Is payable prior to the issuance of Building Permits. 2. The applicant shall be required to pay a Traffic Mitigation Fee of$75 for each average daily trip associated with the project. The traffic mitigation fee is estimated to be $70,320. This fee Is payable prior to the issuance of building permits. 3. The applicant shall subm;t a revised Construction Mitigation Plan which restricts construction-related traffic to off-peak hours between 8:30 a.m. and 3:30 p.m., unless approved in advance by the Development Services Division.- The revised Construction Mitigation Plan shall be subject to the approval of the Development Services Division, prior to the issuance of building permits. 4. The applicant shall pay a Park's Department mitigation fee of$354.51 per multi-family dwelling unit. A portion of the costs of improving A bicycle and/or pedestrian trail, and the recreation building and pool may be applied toward a part of the total required Parks Mitigation Fee. The required mitigation fee shall be subject to the approval of the Parks Department and the Development Services Division, and the fee shall be paid prior to the issuance of building permits. ,ES 1h,_: CITY OF RENTON DETERMINATION OF NON-SIGNIFICANCE (MITIGATED) ADVISORY NOTES APPLICATION NO(S): LUA-97-119,SA-H,ECF APPLICANT: S.E.B. Inc., Eric Blitz PROJECT NAME: Glacier Creek Residential Development DESCRIPTION OF PROPOSAL: Proposal for a 160 unit multl-family development, with half of the units proposed as townhomes and the other half as apartment fiats. The development area would be limited to the east 13 acres of the 47 acre parcel in order to avoid a large wetland area. The proposed development would be accessed off Talbot Road S. and off S. 55th Street. A total of 382 parking spaces are provided, which egUates to a ratio of 2.39 pal"ping SpaCZs per unit. The code requires i.S parking spaces Per unit with one space per 4 units for guest parking, equating to 280 parking spaces. The proposal includes 128 parking spaces in garages, 56 spaces in carports and 198 open parking stalls LOCATION OF PROPOSAL: NW corner of Talbot Road S. and S. 55th Street Advisory Notes to Applicant: The following notes are supplemental Information providedInI conjunction with the environmental determination. Because those notes are`'provided as lnformr rtlon only, they are not subject to the appeal process for environmental determinations. ; process for environmental determinations , CON$ RQCTi0N SERVICE 1. Structural review required for detection vaults, rocY.edes and retaining walls. 2. Accessibility requirements of Chapter 11 UBC apply. . EM 1. The preliminary fire flow required cannot be determined without further information for the multi- family structures. 2. An approved fire alarm system is required to be installed throughout ail structures. 3. Access roadways are required to be a minimum of 20-feet wide with tuming radius of 25-feet inside and 45-feet outside. Both complexes are required to have two access roadways. PLAN REVIEW Sewer A sewer main extension is required for this project, which can be an extension of the proposed main north of the site (as part of the Bumstead development), or connected into the system in S. 55th St. as shown. This main will be an 8' main, and must be constructed per City of Renton standards. The sewer main must be constructed within an easement to the City, a minimum of 15 feet in width. No stub connection is required to the north property line (if the site is connected into the system in S 55th St.), as that property will be served by connection to the main to the north of that development site. 06-566-r„_-.= '-ZEE' It. Glacier Creek Residential Development LUA-97-119,SA-H,ECF Advisory Notes (Continued) Page 2 System Development Charges will be required for this project, as listed on the separate fee calculation sheet. Please not that the charges for the line In S 55th St, are by Soos Creek, at$1625 per unit,where the charges to connect through the Bumstead proposal to the north are $350 per unit. Water An extensive water main extension is required for this project. These extensions must stub to the north of the site (in an easement between Buildings 22 and 23) and into the higher pressure main along the east side of Talbot Road South. A minimum 10' main must be included across the site from the north property line to the connection into Talbot for the southerly development site (invluding a crossing of the creeklwetiand area in the vicinity of the proposed sewer male crossing). The existing 12" high pressure (350 Prassure Zone)water main in Talbot Road South must be extended to the south to S 55th St. A latecomers agreement can be requested for this 12' main extension in Talbot Road South, provided such request is made a minimum of 30 days before the construction permit is issued for the construction of the water main. Future development of the property on the east side of Talbot Road S could provide reimbursement for a share of the cost of wrtstrucl!un of this',Iialer main under su::h an agreenjCnt. Backflow prevention devices will be required for irrigation and fire protection systems. Depending on fire flow requirements, additional hydrants may be required. System Development Charges will be required for this project, as listed on the separate fee calculation sheet. Drainage A conceptual drainage plan and drainage report has been submitted with this application, and is approved as submitted. The conceptual drainage plan includes provisions for detention and water quality treatment in compliance with the requirements of the KCSVW,. ' . System Development Charges will be required for this project, as listed onthe separate fee calculation sheet. Street Improvements Talbot Road South adjacent to the site must be improved with curb, gutters, sidewalks, street lighting, new paving from the edge of existing pavement to the new gutter, and drainage improvements for the new street Improvements. The internal street system will be private streets, and are acceptable as submitted. The pavement width can be reduced to 20 feet in width as shown, since the large number of curbcuts preclude the ability for any street parking. Sidewalks on one side of the street will also be adequate to provide pedestrian circulation through the project. Street lighting must be provided on the private street sections, meeting or exceeding the lighting levels established in City Code. General: All required utility, drainage and street improvements will require separate plan submittals prepared according to City of Renton drafting standards by a registered Civil Engineer. The construction permit application must include a itemized cost estirnate for these Improvements. The fee for review and inspection of these Improvements is 5% of the first $100,000 of the estimated construction costs; d% of anything over$100,00 but less than $200,000, and 3% of anything over$200,000. Half of this fee must be paid upon application for building and construction permits, and the remainder when the permits are issued. There may be additional fees for water service related expenses. 2lab-S=•G-=�-1- Glacier Creek Residential Development LUA-97.119,SA-H,ECF Advisory Notes (Continued) Page 3 POLICE 147.20 Police Calls for Service Estimated Annually Construction Phase Theft from construction sites is one of the most common reported crimes in the city. To prutect materials and equipment it Is recommended that all materials and tools be locked up when not In use. The site will need security lighting and any construction trailer should be completely fenced in with portable chain-link fencing. The fence will provide both a physical and psychological barrier to any prospective thief and will demonstrate that this area is private property. Construction trailers should be kept locked when not in use, and should also have a heavy-duty deadbolt Installed with no less then a 1-112'throw when bolted. Glass windows In the trailer should be shatter-resistant. Completed Building Coded access as entry to each building is recommended to prevent trespassing of individuals who have no right to be on the property. Each unit should have so,id core doors, preferably metal or metal over solid{ wood with Peep holcs r nd dead vQll for;k5�. The halts need t0 be al, te7nsr 1-1/2" in leri th when extended and installed with 3'wood screws. Sliding windows, Including the glass patio doors,will need additional locks: these locks will need to secure the windows from being pried out of the frames vertically: This means the locks wit; need to be placed into the tap or bottom of the frames, in addition to any lock that limits horizontal movement. (This applies especially to the bottom floor windows that are hidden from view.) Alarm systems are recommended for each unit. The stairways at the complex should be constructed of lattice or metal railing so visibility is possible through the stairway. There should not be any solid walls in any stairway that would serve to limit the visibility up and down the stairs and provide a place for a criminal to hide while waiting for a homeowner to return home. In additional, the balcony walls also need to be made of either metal or wood lattice or railing- no solid walls for the same purpose. Extra security lighting needs to be installed in the parking lots, along the sidewalks, in the stairways, and between the buildings. Measures should also be taken to provide additional lighting for the common trash dumping site. Since this is located away from the complex itself, proper lighting should be provided to assist in making the area safer for the residents. Each unit should have their individual unit numbers listed clearly,with the number at least 6' in height of a color that contrasts with the color of the building and placed under a light. This will aid police or medics who respond to a call in finding the.unit they need to go to November 20, 1997 OFFICE OF TI-1;.E HEARING EJiA IINE'R CITY OF RENTON REPORT -AND DECLI;ION APPLICANT: Fric Blitz, S.F.B. Inc. Glacier Creek Residential Development File No.: LUA-97-119,SA-H LOCATION: NW Corner of Talbot Road S and S 55th Street SUNTMARY OF REQU7'ST: To construct 160 multi-family units,half as townhomes and half as apartments, on 13 acres. SUMMARY OF ACTIC,N: Development Services Recommendation: Approve with conditions DEVELOPMENT SERVICES REPORT: The Development Services Report was received by the Examiner on October 28, 1907. PUBLIC HEARING: After reviewing the Development Services Report, examining available igforniation on file with the application, field checking the property and surrounding area;the Examiner conducted a public hearing on the subject as follows: �CrrES The following minutes are a sununary of the November 4, 1997 hearing. The legal record is recorded on tape. The hearing opened on Tuesday,November 4, 1997,at 9:20 a.m. in the Council Chambers on the second floor of the Renton Municipal Building. Paities wishing to testify were affirmed by the 1'✓xarniner. The following exhibits were entered into the record: Exhibit No. 1: Yellow rite containing the original Exhibit No.2: Vicinity map app'ication,proof of porting,proof of publication and other documentation pertinent to this request. Exhibit No.3: Site plan Exhibit No. 4: Landscape plan F., Building elevations Esbibit No. 6: Wetland map Exhibit No.7; Shadow plat inap The hearing opened witl.i a presentation of the staff report by)2F T .R ROSEN,Project Manager,Development Services, City of Renton, 200 tv-fill Avenue South,Renton, Washington 98055. The applicant requests i + Eric Blitz, S.E.B., Inc. Glacier Creek Residential Development File No.: ILIA-97-119,:iA-1.1 November 20, 1997 Page 2 site plan approval to construct 160 multi-family units. Half of the units are proposed as townhouses and the other half as apartment flats. This site is located along the south City limits and is bordered on the south by S. 55th Street and the cast by Talbot Road S. It is in the R 14 zori= acid in that area there ace several large tracts that remain undeveloped at this time. 11e overall site area is 47 acres,but the development area is limited to the east 13 acres. There is a large wetland area that takos up th-. entire west portion of the site. That wetland is a headwater for Springbrook Creek which enters the site on the north side of S. 55th Street and exits off to the southwest corner. It is a Category 2 wetland due to the large size and headwater location. The development is oriented towards Talbot in order to avoid direct impacts,to the wetland. Can the site there is a branch of the wetland that goes to Talbot Road. There is a 50 foot buffer requirement for Category 2 wetlands and the applicant is proposing to use buffer averaging. in addition there is an interncittent stream that enters the site through a culvert about l50 feet south of the northeast corner off Talbot and flows into the wetland area. Because this is a man-made wetland due to road improvements, it is not considered a regulated wetland. The wetlands break up the development on the site and also arc. the crganizinl; feature in terms of where development could be located. The development includes 80 townhouse units which are ground-related units. They are focused along the internal road system and all have driveways and garages and maintain frontyard setbacks from the road area. The street system that has been approved for this site is a private road,20 foot pavement with a 5 foot sidewalk that is continuous along one side for pedestrian access through the site. It is anticipated that there would be trails developed on the site. There are 80 apartment units or stacked units where the second story dwelling units are accessed from an internal stairway. There tire 10 apartment flat buildings and they are all oriented towards Talbot Road. Bach apartment building contains 8 units.The proposal also includes a common recreation building witl%a pool and spa area which is in the middle of the site and focused along Talbot Road. There are 382 parking spaces provided which does equate to a ratio of 2.39 parking spaces per unit. The code requires 1.5 spaces per unit with one space per four units for guest parking which would be 280 parking spaces. Of the ones that are proposed, 128 are in garages of the townhouses, 56 spaces are in carports which are basically on the back side of the apartment flats, acid 198 open parking stalls. The Examiner asked if this application needed a parking deviation as it exceeded the parking provision by approximately one-third. Mr. Rosen responded that it probably would. He pointed out Obit 128 of that total are in garages for the townhouses. All the parking required for the townhouse units is essentially in garages so the other spaces are more earinarked for the flats. The parkins areas are broken up and there is landscaping that enhances it. It avoids continuous head-in parking,so in terms of the overall design there were are no large expanses of parking that take away from the overall site plan layout. In terms of eliminating them for more wetland buffer,none of the parking is directly located adjacent to the wetland buffers. This proposal went to the Environmental Review Committee(ERC)on October 7, 1997, and received a Determination of Non-Significance- Mitigated(DNS-M). The ERC mitigation measures included fire,traffic and parks citigation fens, and also addressed tli,. construction mitigation plan and restricting construction related traffic to off-peak hours. The site is designated Residential Planned Neighborhood (RPN) in the Comprehensive Plan(CP)and is intended to create opportunities to develop new neighborhoods with a variety of housing types and incorporating features from both single family and tnulti-fancily development. Overall the developments should have the characrer of a neighborhood rather than a multi-family complex. The subject proposal is consistent with the objectives of the RPN designation. Eric Blitz, S.E.B.,Inc. Glacier Creek Residential Development File No.: LUA-97-119,SA-H November 20, 1997 Page 3 The R-14 zone is intended to encourage a mix of dwelling unit types of detached and attached units,organized avain as a develoortient.to i nci-hborhood char.,-t`.T nn l fir.neral"N.to limit the scale and intclisity O tllc'. rrlillti- family development to townhouse, ground-related units and smaller scale apartment flats. The R-14 zone specifies primary and secondary types of residential uses with a bonus provision which allows for an increased density of tip to 18 dwelling units per acre and also allows larger or more units per structure. The subject proposal has a density of 12.31 dwelling units per acre. The density was calculated over the 13 acres, not the entire wetland. The density for this zone has a range of a minimum of 8 dwelling units per acre and a maximum of 14. The density provision allows up to 18 units per acre. The applicant does not need the bonus provision for the density proposed;however,they are seeking the bonus provision for the number of units per stricture. The bonus provision is divided into project features and project design. The applicant is proposing the recreation center,common open space,and two tot lots;as well as architectural design incorporating building entry features, e.se of gabled roofs, and varied roof pitches. The R-14 code requires this application. include a shadow plat to show that the development would meet the equivalent standards in tcrtns of lot area, setbacks and access infrastructure. This application met the minimum lot areas and the lot width dimensions and setbacks. Staff is recommending that the applicant provide further information specifically about the towiihouses meeting the sidevard setback requirement which is 5 feet,as it is difficult from the scale of the plans submitted to ascertain. The applicant is proposing a sewer line that would cross the east arm of the wcaland that is between the south development pocket area of the apartment flats and the other part of the development. Any disturbance to the wetland and buffer would be required to be mitigated and staff is recommending that the final wetland mitigation plan analyze the extent of those impacts and provide for mitigation. This project could connect into the Soos Creek sewer system on 55th,or they could extend the sewer main down Talbot. The storm water is being conveyed to detention vaults which are located along the western edge of the development and will be released to a bioswale and disbursed to the wetland with a flow spreader. Storm water facilities such as that are permitted to be within wetland buffers. There is a 50 foot wetland buffer for the Category 2 wetland. Regarding the stream on the north end of the site, there is a 25 foot buffer requirement from the.high water mark. There are areas where there rnight be some building encroachment by buildings 18,26,and 4,but the applicant must meet that buffer requirement. The applicant would be crossing the stream in order to provide continual access through the site and that may trigger an Hydraulic permit Authorization which they would be required to obtain from the State Department of Fisheries. The access to the site is from two driveways off Talbot, one in the very northeast corner of the site and one by the recreation center in the middle of the site. The south part of the site that would be apartment.flats would be accessed off S. 55th Street. A traffic report has been prepared which concluded that with the cumulative impacts of three pending projects iii.this area that the level of service would go from E to Fat the nearby intersections. The Parks Department identifies both a bicycle path along Talbot Road and also a general trail alignment through the site. The bicycle trail would be required as part of the right-of-way street improvements for this project. In terms of the recreation trail,Parks Department has recommended that applicant provide a 20 foot wide recreation easement. Staff had initially communicated to the applicant that the trail could be located on the wetland side of the buffer, but in order to still provide some buffer width between the trail and the wetland Eric Blitz, S.E.B.,Inc. Glacier Creek Residential Development File No.: LUA-97-119,SA-H November 20, 1997 Page 4 it has been determined that it should be moved to the development side. This is a major trail feature which is intended to link tip to Saringbrook and which the applicant is required to provide. Passive trails are allowed as exempted uses in wetlands and wetland buffers. Parks Department has recommended tlrat zpplicnnt ronstmc.t the trail with the develcpr*cent. The specifications that Parks has agreed to is a 12 foot wide soft surface trail within that 20 foot easement. Up to 33% of the parks mitigation fee could tie used for the trail improvement. This proposal meets the site plan criteria regarding adequate light and air, mitigation of noise, odors and other harmful or unhealthy conditions and prevention of neighborhood deterioration and blight. Staff recommends approval of this proposal,subject to the following conditions: (1)compliance with the ERC mitigation measures; (2) that the applicant provide further detail to confirri: that the townhouse structures meet the 5 foot side yard setback requirements; (3) a final wetland mitigation plan that would include construction details and mitigation of Elie sewer line crossing, addressing wetland buffer width averaging criteria, as well as \'Critic aOuii lhat rt nit.ias lac.si(-cam ;ietba-k &zduirei►ceilt; (4) flat the site plan muludt: a 20 foot wlue recreation trail easement oriented on the upland side of the wetland buffer. Ryil C!sev. 10116 36th Avenue Court SW, #109,Tacoma, Washington 98499, architect for applicant, stated that this proposal did in.eet the 5 foot minimum setbacks between buildings. The submitted drawings were prepared using Auto-Cad software with the unit sites shown on the exhibits and they do meet that criteria. Regarding the stream setbacks for buildings 26,4,and 18, it is also a question of the line width on the drawing from what the computer knows is there to what is graphically seen. If there is an encroachment,the buildings can be shifted to remain outside the buffer. Regarding the parking calculation for this project,lie explained that half of the units are townhouse units of two and three bedrooms,with one or two-car garages attached and a driveway in front of each garage. The total stalls for the townhouse units is 232,counting the garages and the driveways in front of each. There are 80 apartment flats and thehe are 141 stalls provided for those units. Mr.Casey requested the opportunity to work with the Parks Department in creating the pedestrian walkway which would ensure privacy for the residents as well as reduce the wetland impacts as much as possible. Eric Blitz, 4109 Dridgc.port Way West, Suite C,Tacoma, Washington 98466,applicant herein, addressed the location of the proposed trail, citing the need for privacy and safer;, of the residents. Applicant supports regional trails, but questions the nature and location of this trail. L\Jr�_ R sea explained that this trail could be moved further to the west to avoid some of the impacts, but staff felt that having some wetland buffer between the trail and the wetland edge would minimize impacts to the wetlands,and that is one of the criteria in the Wetland Management 10rdinaricc that precedes the exempt activities. Neil Watts, Plaii Review Supervisor,Development Services,City of Renton,2001N1.ill Avenue South, Renton, Washington 98055, stated that this area is in the City's service boundaries both for sewer and water, although Soos Creek does serve south of S. 55th. Water service is available on Talbot,but it will require an extension of a 12 inch .eater main down Talbot. There is a sewer main in S. 55 that is a City main. It does enter into the Soos Creek system. There is also a sewer system north of the site which does not currently come completely to this site. It is one development north of this site, and as part of that project development they will be required to extend the sewer through their site to the northerly boundary of the subject property. Eric Blitz, S.E.B.,Inc. Glacier Creek Residential Development File No.: LUA-97-119,SA-H November 20, 1.991 Page 5 Street improvements woald include full frontage improvements along Talbot Road, and would include concrete curbs, sidewalk and some limited pavement widening. Talbot Road is an arterial in this area and would require :!three lane section, !c.ft titre. lantt, wid bile lanes alon,' h;xh sides. Regarding parking, Mr. Watts explained the basic planning concepts in the R-14 zone and tha difficulty of P t3' doing parking counts as compared to a normal plat. The Examiner asked what the provisions for community or guest parking were and Mr.Rosen explained that there is limited open parking in the townhouse section of the proposal. Tile parking count includes the garage aprons which are considered tandem spaces and allowed by code. Mr.Watts explained the traffic and level of service and how the City computes the impact to the nearby intersections and adjacent areas. Relative to the parking ri.quirement,Mr. Casey indicated that applicant could add more guest stalls to the townhouse area of the proposal, and with those additions could meet the intent of the parking code. The EaAmiDer called fot further testimony regarding this project. There was no one else wishing to speak,and no further comments from staff. The hearing closed at 11.:22 a.m. ERMINGS. CONCLji„DONS & DECISiOti Having reviewed the record in this matter, the Examiner now makes and enters the following: FINDINGS: 1. The applicant, Eric Blitz, filed a request for approval of a Site Plan for a 160 unit apartment complex. 2. The yellow file containing the staff report, the State Environmental Policy Act(SEPA)documentation and other pertinent materials was entered into the record as Exhibit#1. 3. The Environmental Review Committee(ERC), the City's responsible official, issued a Declaration of Non-Significance-Mitigated(DNS-M)for the subject proposal. 4. The subject proposal was reviewed by all departments with an interest in the matter. S. The subject site is located at the northwest corner of Talbot Read South and South 55th Street. The site is located Nvest of Talbot bznvicen Talbot and East Valley Highway. 6. The trapezoidally shaped subject site is approximately 47 acres in area. The subject site is approximately 1,301.63 feet long(Talbot frontage)by approximately 1,600 feet deep. 7. The applicant generally proposes developing the eastern 13 acres thereby avoiding large wetland areas located on the western three quarters of the subject site. The development will actually work around an intermittent creek that crosses east to west across the site and a portion of the wetland that extends eastward from the main wetland area. In addition to the intermittent.creek, Springbrook Creek crosses through the southwest corner of the site. The wetland is a Category 2 wetland. Eric Blitz, S.E.B., Inc. Glacier Creek Residential Development File No.:LUA-97-119,SA-H November 20, 1997 Page 6 8. The subject site was annexed to the City with the adoption o,`Ordinance 3268,enacted in December 1978. 9. The subject site was zoned R-14 (Multifamily Residential; 14 dwelling units per acre), its current classification, on June 1993 with the adoption of Ordinance 4404. 10. The map element of the Comprehensive Plan designates the area in which the subject site is located as suitable for the development of a residential planned neighborhood but does not mandate such development without consideration of other policies of the Plan. The Comprehensive Plan suggests that this area should support a mixed residential community with a variety of housing types incorporating single family and multiple family features. 11. The applicant proposes 32 buildings containing a mix of two story apartment buildings and townhouses and a Separate r-ecreationAl building. T)fem-wi!l he 10 eight-unit apartments. There will be 16 four-unit townhouses,4 three-urlit townhouses and 2 rive-unit townhouses. 12. The complex will be divided between two locations on the site. The majority of the development will be in the northeast quadrant of the site. The remaining four units will be located in the southeast corner of the site with a separate access road. The division is dictated by the location of the creek and wetlands. 13. In the north division, some of the multiple family,multi-story buildings will be located along Talbot, reserving the inner, presumably quieter portions of the site for the townhouses. Some buildings will be aligned along the cast and north property lines while the others will create a gentle meandering pattern following the contours of the site. The four units in the south division of the site will be arranged in a quad fashion around centrally located parking. 14. The north division will have an internal loop road served by two driveways along Talbot. The southern division will be served by one driveway to S. 55th Street. An emergency access plan would permit the sidewalks in the southern division to serve as an alternative access. 15. As indicated,packing for the south division will be in the center of the building complex. Parking and garages will be located to the west or rear of the Talbot buildings as well as on individual building pads. The applicant proposes 382 parking stalls divided into garages(128),carports(56)and open spaces(198). The proposal requires 1.5 stalls per unit(160 units requires 240 stalls)plus .25 stalls per unit for guest parking(40 stalls). Unlike some uses,there is no maximum stall limitation. Since the . proposal is an open apartment type complex rather than individual lots, many parking spaces would be available on concrete pads or aprons adiacent to individual buildings. While sonny; guest spaces would be available on the aprons of the units,those would appear attached to the living units. The use of those spots by guests of other units could also block garage access. As proposed there would be a limited amount of"guest" spaces near the recreational building and a scarce few other locations. 16. The subject site is in a generally undeveloped area. An application for property to the north has been submitted for review. The Sikh Temple and a multiple family development are located cast of Talbot in this vicinity. There are scattered single family uses along both sides of Talbot. The zoning in the area reflects the proposed use. 17. The development of the subject site will generate approximately 938 average daily vehicle trips per day. The main inten3eetionS which would be affected by this development would generally be at Talbot Eric Blitz, S.E.B., Inc. Glacier Creek Residential Development File No.: LUA-97-119,SA-H November 20, 1997 Page 7 and 43rd and the entrances to SR-167 in that vicinity. The level of service would be degraded from LOS E to LOS F. The City has new standards for analyzing traffic impacts that don't rely on LOS but "ConcurrCttcy tlrnes" or avcrF1aC trlve.l 14TICS. TI?C &,- rtdation is corl,idt rcd minima}. 1n addition,the ERC has imposed a mitigation fee of.S70,320.00 to offset the impacts. 18. There will be th.s standard 25 fort Buffer observed on both sides of the central creek. The applicant will be providing a wetland buffer that averages 50 feet. The applicant will employ buffer averaging to allow development of approximately 134,037 square feet of buffer area and setting aside an additional 139,926 square feet to create additional buffer but never reducing the buffer to less than the minimum required 25 feet. As noted above,the plan details and dimensions do not clearly demonstrate that the precise setbacks have been observed. The applicant shall either observe the appropriate setbacks or apply for the proper variance. Some additional disturbance:for utilities or roadways may occur as permitted,although the sewer alignment has not been determined. Another wetland area was dcterm.ined by the applicant's consultants to be "mnn-induced" and therefore not necessarily subject to preservation. 19. The R-14 Zone requires the creation of a shadow plat to create guidelines for building setbacks, lot area and lot width. the plan details have made it difficult for staff to ascertain if the required setbacks between various elements of the site have been observed. Staff and the applicant agree there is room to shift building locations to accommodate the required setbacks. All setbacks will need to meet code requirements even if the current plans indicate less than the required setbacks. 20. Tile applicant proposes a density of 12.31 units per acre which complies with the range of 8 to 14 dwelling units per acre required by the Code. 21. Bonus design features permit four attached units as opposed to the three normally permitted in the zone. The applicant is seeking approval of this bonus. Additional building length is also permitted but the applicant will observe the standard building length of 85 feet for all facades. The applicant is providing the recreational building,tot lots and clearly the vast undeveloped natural areas. The buildings also include varied materials and modulated facades and rooflines. 22. Both water and sewer lines will need to be extended to serve the subject site. Topography and existing sewer lines may make a hookup,more complex. CONCLUSIONS; 1. The site plan ordinance provides a number of specific criteria for reviewing a site plan. Those criteria are generally represented in part by the following enumeration: a. Conformance with the Comprehensive Plan; b. Conformance with the Building and Zoning Codes; C. Mitigation of impacts on surrounding properties and uses; d. Mitiga.ion of the impacts of the proposal oil the subject site itself; C. Conservation of property values; f. Provision for safe and efficient vehicle and pedestrian circulation; Eric Blitz, S.E.B., Inc. Glacier Creek Residential Development Pile No.: LiJA-97-119,SA-H November 20, 1997 Page 8 g. Provision of s adequate li ht and air h. Adequacy of public services to accommodate the proposed use; The proposed use satisfies these and other particulars of the ordinance. 2. The proposed complex with the mix of apartments and townhouses is compatible with the goals and objectives of die..Residential Planned Neighborhood. It not only has the two housing types but it also preserves large areas of wetland, incorporates interesting building types with varied facades and rooflines and unifying landscaping. 3. The recreational building provides the central focus required of this Zone and for this type of deVelopnlent. Tllr wetland :?rid x ter features could also serve as 7 fo::01 point alttinng!l in 8 unique way. The applicant has taken extensive steps to preserve the wetland and provide adequate buffers around it and the creek corridors. The buildings are linked by paths and roadways and a common landscaping theme as suggested by the Comprehensive Plan. 4. The development of the two housing types, 80 townhomes and 80 apartments in a 50/50 mix meets the requirements of the Zoning Code. 'these dwelling unit types represent ground entry units and two-story apartment buildings. 5. The site's downslope position from Talbot serves to buffer the surrounding uses and to lower the entire profile of the development. Clearly, there will be increased noise associated with residential communities and there will be increased traffic generated by this and other projects along this corridor. The traffic analysis indicates that traffic will get worse,although not significantly,but the reality is 1 new development will have adverse traffic impacts. 6. The applicant has done an admirable job working with the site's constraints, including the slopes, the streams and the wetlands. The applicant will be preserving between two-thirds and three-quarters of die site in wetlands resmations. The applicant will be buffering the smaller creek which flows east to west across the site and the wetlands will buffer the segment of Springbrook Creek which flows through the site. The buildings are reasonably clustered yet provide sufficient spacing to allow the passage of air and light to penetrate into the site. The two-story, low-scale nnture of the buildings,the building and roofline articulations and the elevation changes across the site all help mitigate the impacts of the development on the site. The features included by the applicant appear adequate to offset the bonus which allows additional attached units. As noted, all building shall be required to meet all setbacks from each other or the various buffers and shadow plat requirements. 7. Tlie development of the site should add to the t"- base of the City and should not have an adverse impact on property values in the area. a. The circulation pattems appear reasonable for both vehicles and pedestrians. The proposed extension of the trail system should not interfere with the privacy of residents. Since trails are permitted within the wetland buffer, it should be moved there to preserve and protect the privacy of the residents. Also it would alloNN better observation of the wetland values that will be preserved without unduly affecting those values. The applicant and the Parks Department should work together to design the path and choose surface.materials,but since the path will be in the wetland buffer it should be designed and surfaced to require minimal nlaintenaczce after its development. Eric Blitz, S.E.B., Inc. Glacier Creek Residential Development Fite No.:LUA-97-1.19,SA-H November 20, 1997 Page 9 9. While the applicant proposes approximately 100 more parking spaces than required, their location makes them problematic for guests. Most of the so-called guest parking is tied to the building pads or garage aprons of itidividnal uni+s. NYhile in theory these spaces might be available to guests visiting other units,that does not appear realistic. The site's isolated location and the absence of readily available street parking on the narrow internal streets or along Talbot require that suitable guest parking be provided that will not interfere with garage access or create potential friction between tenants and guests. The applicant shall create additional parking in separate lots not associated with individual units that meets at least three-quarters of the required quest parking or 30 stalls. These stalls may include those already associated with the recreation building. The applicant might be able to create severals stalls as "pull-outs" if it narrowed some of the parking aprons(see attached detail for suggestions). 10. It appears appropriate utilities can serve the site although extensions will be required. Those extensions should he chosen and located as to cause the least disturbance to the natural features of the site. 11. In conclusion, the site presents unique characteristics and it appears the plan as proposed and conditioned should be an asset to the community and City. DECISION- The Site Plan including its bonus offsets is approved subject to the following conditions: 1. All buildings shall be required to rnee.t all setbacks from each other and the various buffers,and shall meet the requirements of the shadow plat requirement. All setbacks shall need to meet code requirements even if the current plans indicate less than the required setbacks. A revised plan shall be subject to the approval of the Development Services Division prior to the issuance of building permits. 1 2. The applicant shall create additional parking in separate lots not associated with individual units that meets at least three-quarters of the required quest parking or 30 stalls. 'These stalls may include those already associated with the recreation building. 3. All utility extensions shall be chosen and located as to cause the least disturbance to the natural features of the site. 4. The proposed trail shall be located in the wetland buffer so as to not interfere with the privacy of residents. The applicant and the Parks Department shall work together to design the path and choose surface materials, but since the path will he in the wetland buffer it shall be designed and surfaced to require minimal maintenance after its development. 5. The applicant shall comply with the ERC mitigation measures prior to the issuance of a building permit. 6. The applicant shall provide a final wetland mitigation plan when construction details of the sewer line crossing are available. The applicant shall provide appropriate mitigation for impacted wetlands in accordance with the Wetlands P.'lanagement Ordinance. The final wetland mitigation plan shall also address all the criteria listed in Section 4-32-3.1 of the Wetlands Management Ordinance for allowing standard wetland buffer width averaging. The final wetland mitigation plan shall be subject to the approval of the Development Services Division prior to the issuance of building permits. Eric Blitz, S.E.B.,Inc. Glacier Creek Residential Development File No.: LUA-97-119,;iA-H ' November 20, 1997 Page 10 ORDERED THIS 20th day of November, 1997. FRED J. KAUIaAN HEARING EXAlyffNER TRANSMITTED THIS 20th day of November, 1997 to the parties of record: Peter Rosen Pau1 Casey Eric Blitz 200 Mill Avenue S 10116 36th Ave. Ct. SW,#109 4109 Bridgeport Way,#C Renton,WA 98055 Tacoma, WA 98499 Tacoma, \VA 98466 N1cil A'aas Debbie Livingston Owen Bing 200 Mill Avenue S 9533 S 192nd Street 5310 Talbot Road S Renton, WA 98055 Renton,WA 98935 Renton,WA 98055 TRANSMITTED THIS 20th day of November, 1997 to the following: E � g Mayor Jesse Tanner Gregg Zimmerman,Plan,Bldg,TW Administrator Members,Renton Planning Commission Jim Hanson, Development Services Director Art Larson,Fire Marshal Mike Kattermann,Technical Services Director Lawrence J. Warren,City Attorney Larry Meckling, Building Official Transportation Systems Division Jay Covington, Mayor's Executive Assistant Utilities System Division C.ouncilperson Kathy Keolker-Wheeler South County Journal Pursuant to Title IV,Chapter 8, Section IS of the City's Code, request for reeonsidet-alion nii,st be filtdin writing on oi-ht.fare 5-00 pan..December 4„1997. Any aggrieved person feeling that the decision of the Examiner is ambiguous or based on erroneous procedure,errors of law or fact,error in judgment,or the discovery of new evidence which could not be reasonably available at the prior hearing may make a written request for a review by the Examiner within fourteen(14) days from the date of the Examiners decision. This request shall set forth the specific ambiguities or en•ors discovered by such appellant,and the Exarn.itier may, after review of the record, take further action as he deems proper. An appeal to the City Council is governed by Title IV, Chapter 8, Section 1.6, which requires that such appeal be filed with the City Clerk,accompanying a filing fee of$75.00 and meeting other specified requirements. Copies of this ordinance are available for inspection or purchase in the Finance Department, first floor of City Hall. If the Examiner's Recommendation or Decision contains the requirement for Restrictive Covenants,1b_Q exect►tc�( oyen nts trill he reptai e mint'to UXQyal bti:City Council or finale CessinQ of the file. You may contact this office for information on formatting covenants. The.Appearance of Faisncss Doctrine proviees that no ex paste (private one-on-one)communications may occur concerning pending land use decisions. This means that parties to a land use decision may not Eric Blitz, S.E.B., Inc. Glacier Creek Residential Development File No.: LUA-97-119,SA-Fi November 20, 1997 Page 11 communicate in private with any decision-maker coneeming the proposal. Decision-makers in the land use process include both the Hearing Examiner and members of the City Council. All communications concerning the proposal must be made in public. This public communication permits all interested parties to know the contents of the communication and would allow them to openly rebut the evidence. Any violation of this doctrine-,,vouid result in the invalidation of the request by the Court. The Doctrine applies not only to the initial public hearing but to all Requests for Reconsideration as well as Appeals to the City Council. i 1 1 Eric Blitz, S.E.B., Jnc. Glacier Creek Residential Development File No.: LUA-97-119,SA-H November 20, 1997 Page 12 i 1 r M M = r r MMMMM M MMMMMMM CREEK A rcvmo►i cF aW v v <a�T�oe 4 of oecrlat 2t r n►t r.I wu [ [ ••••-•_ •-••••_ y��Y� " t►.ut w aw.rr •n.r.r•r�w�,v.....� i ��i r i t 4 ME PLAX UMOVAL APPLiCATION � 1 —=—• ••a•�•,•�•-�, � � ����_ !: � ! •[ PLiN ,� ( (-� :"'` :, p—�? � ':T�.:;' v: s:' Sit licr pia 1ti la-off f d •t_k � O _ _may— .�•_�^ ••�� �L_,�_%•_.\`_� I�� JI l i�(� /- fi.:J ` c < n '2 I c .� -ya�}.•.� {ti., i.. -rf.�. c 11/� .3.x y�� _ n. .�/ t• ~ �•, ` ls/:- ��•`i��.:�,� R r . w+.1J [.. •19� ��L 1 1 is 14 Tw ,�{ • .,�' '1`.�----•t�---•r + / ��� / ~-- y��-mot'-f, � ' Q Nil ./ +'*^ /C// .. .-.t_-c-+�r�-_, •� '/1 \ ��/f ' It � U o..y } , 11 .• \w3h—S?. v l./{�i,w }?�i�' ( U 2 /r!Ih.•'� PACIFIC ENGINEERING DESIGN INC. p CIVIL ENGINEERING AND ---� PLANNING CONSULTANT ... . ........ falTof • v-,,,c3-- 5-m L J 0 fA 0-FA.&; r, FA 0-1A D—C Ct Y..I 1 3 1 M11 71 • I a :1 1 Y-5-6 I 0-F K I L6 t 16 , Inc . ILL: IS% III 7—L— , I -3� "S. L% D. ;-4 r a b A lei !L Al 0 j Aj ----------- Ply (gymy Girounp ArCII&MOB aichitecture And P!arinfng I.! c C-n4 C-FRI V) All 4P ArchjtccturcAr)dPLwnn1ng !ttIlII N - ifeiLit�10 I� (�_; wln S A\ a vu+ �� IV�C`i rsniV�SB��I t1�GR+M a rJT�!:� ` m>r 11i r �g Cmey G'IMLOP srchltcc:u,-c And Planning rV *MUM= tti,+ � a� YY� 'iroJ,����• t��K�l��•1Yrtw► i L. 1.'r1�a rM + Y- its 1' �,� •„ 44Fmi 1J�• � 1i / ut � RM1S{� r• y YES+�� v:" ' ` •+,�✓+Y„i��ti� WIN ,ij � � .,•;��., •' 1 ie rai. r��e t,/� :1. � � ITV :. 1.Lr .t`Gs' •� ►err, y-;:':;,�.�' ,4��.. +'� . �i 4 1-T� p V 1. !'�}�� .ifs!� • �y� � r � r.;> IBM I� 2 25 \ ( 30 ��V, a�J6 203 �\ • - • 1. m 17 'I BM ------ --- - -- --- — — -- MI 17 - — - — — — -- I I q• � �� ai• 'C;. !l .,� ',:'�( ! �-'l�� `t ;III 7�I: •,. ravel ': — 1 !, ' 36 BM I �W, 1 r a"aeh. NA k � I• •✓� " ' .�___- ' �� aaster. - : _- _� _ HAY E INu � Ki A .—.-'---- -j� '• �, 1 :If •�� •N. bS Th' eaters ---- \ ' 'S L,,II p ' lKi : : .s It 1 ' •I �l r �1 � 'i.... '-I• J� ' 1 1e NIP —J�c /* r It Q n12 '\• C\ U. Jp� •�• r ��.I �s i - '' Trailer r v\••• ;: I •111��1 Park l II^\�. IQ 1 • . USGS TOPO MAP _ r r 'rr r � r r �r r i r r r r rr r rr r {.y ,r, ,. _ssi,r� , , _ . ., r I�.y-i-...--.�'J'rt r. i r ..., r Yt'4'�1`.t�,••�.a-+ � 1 � r ��. .�... '�rl� :-i�-'� tL ��t-�-}�+r f/ —_�.J•1.�,� .-_' IL r ",If•�' �.•�r:+- `7•-�` �j ♦LN,•r p4r no, Minor f ' {�r:L•7 : j,(1 t .1 '•� �`ii�+'. �.r- { ! j' __ .. .���.n 1.J�,'''• t��` h R•A._ r �lKtit{ '...••:%'1 i •1 1 rf I i "� (-t= .( ;._i,.,! .tf! TO o••iifan••er•.t, '.' .—.-•� •E a.,_• .�I 1 �.'\�17 a7 ,..,'i S,L L$f';r 1' �_ J ,� �•.�. 3r �_�. IE:, L gLf��i ±. f�; r ' ,ff. `j t'��: �l•-•r :i '..ir v11 � 4� �r�. 1 _i-,, �.... t I/� t1• ��f )♦•'1' 't'1: { ...�•y- r- tr ' stock 1 ir ,� �'(t �''� ^�'• •i �=j i•! - -,.r N • ._3_ .1 j' �—' = .1k / ♦ !: J tom' 3 .j_t -!tie IN ti i d 3Y .�.�. �t1 4� •{1 _.L l'._I 11-. �' J ra •.1 r-l= L _71• fr'J (L_ ( 1( -f �•.� >~ 3_`.z1i,lr-• �.1-�.� Sli `.i\'. ,I .� r�.� •�•y..r l.. J�f 1• -1_ ' a:+ice` -�•:,. ! •..M t A} Ww.n1.: j r r 'i' a' .. —� I 7• 7 _ Mw,ry 1640d ., .... � ~, I'., I• .. �'i,ir�:�� � .--! ..S ����� J.'1 r. r Irk r•� ;�. •t 1 r 7 r `�: - •i..,'�' �I q` ! f 1 M. ) +n :t _ 07141 s� j •1� Y �� r / +f('S. tr,1 ^ !, ( •�yY ,. l ,I'� ';0 �1 ' t :. �! 3 _ • _ Y:`. j:L•1 •••/ .11t .jJ 3 •T�'tMJ I(31 _, h�'•. ,'i•.. , •�""1 .ri: T Th area or the w incorporated e wetland ad to the i rated a should not. ( �3 _ - ,�, ` 1 '•; 'r �'^ .i ? ...NNN 111 _ . .__ :. � � m_ ••.�tli I-��-'�1,�: 'j .�7��W .Lt.. f� L--_ l•� 1%' -r� Y�i�i•�.: "'sy i s ' be shown as it is no longer under King County jurisdiction ' -'= y��+ r f� �r f��'� '� 1 -:�'�• 7� •sfLl. Nt:X's°r-, 1 .Eso1f__t+ _ -- - ri !~ ( �`' r ZM-C '=1.1 I =fc ,4r?t i�?1i� '�-r"7m _ ..t 3 `�-' t!� r >s / •aosa .�. _ l 1 !„ 14 1� �/ 1• ; , .i`j Ltn+w6 IIIVN '1•� f Y rt ti 1; r J _ cn + 3 1.-.-t v+ �•; r it 1 ���..lr,[�.t.'t..! -I�.f `.. ' � +,4:�= .:r `_ r_.._f � �' � Ic.�� _ �` r' ` . , / JY ,R ll/� ' l�31�•tt�"5`�-�+� t 1 t•• �..-.>'�•';•�-`!J 1~� �� �r. ? 1 t 1 T_L.Jr ' - �� ♦� �..� v O. : :••��• �, + .. 7i Vljil%BUJ Wt11Md. Kum - J r:Yl SJ..T•A'N :.IK '�{ •�•,t t.,t H.,�,.,t:•�..:! I•r.. ', ... '•t' •i:t�N11•rf' f• �� BYh,90Und.fM ^�9!,� ..•, H••. ..ii•.. , �. a. .. .. •t•' �� Subbuln[tound•fia• err �■r r� r� ■r goo M M im it M M M ■r it M r.= '...o a.W WC21 'O.-J 191-..i W-) ViEd G:u 4-7:.7.�\ ( :h.�f.. •1.��.1 rJ _ T. 11 + ' `i+�i• .+ I� r�t r jai ter, s'j, - "_ .? — �-1,, g.1 14 4• -r, —'�♦ ,1.1 ?/ _ ��+ � _ram! :i. IV A -- it !(' •.( ?/ f �' +� •il .._ � ,; ::•, i•�,; v�.`� •f,,..l l__...•---1 r..a• •.t••f' J .ice!.�• • .t• , \ •t•�v ,L 1. .t� ' 1 "�• l —+�Y'S.cc •;+1 r. ••+• �» +f rp U+r '=i 1. �y'• t 1 i't i .i � 1_I��' +1 1 .Il.l I +,` '1+J •, I 1:2 n611:11 OI IN.+iMdbJ aHa, ail• Onf• .— � l:;r.eN.;a a•nwp tl .a,a ax.,t,.in..+.an„ a i.na++o +I+pOOlaln t0 IN. N..tl4wOa,.,f + +,,•a.,l. � " Kent Yintl Streams and 100- Clu 2(w hh ulmidt)Clat 2'trennld;tstmonidMU Year FoocplainsN :,:•• = s Irf.undo nm;nad) ,, maw n.e,rJ,eu,On.lnbM,meuwa r.a• ,%.a—iu +.M•u..r.MJ+n,/.•+NIO OI rnf,enl.11.J •. • • ^ y•Cl 7 1.r1 n . m IM SIMi4.. A•.J O.oban+l.1,if:m Nn1,raM,a. =lOOYw FlOOdprdn ———Unc,ufKod M. Off-Site Analysis LEVEL ONE This site is located along the westerly side of Talbot Road South. The entire site drains westerly from this roadway towards SR 167. Upstream runoff crosses under Talbot Road South in two separate locations and joins with the on-site runoff. The developed site is split into three separate drainage basins. For the purposes of this report they will be called the North (A), Central (B) and South (C) basins. The site is located within the Green River Basin. The developed site is within 1/2 mile of Springbrook Creek which is a Class 2 stream with salmonoids. Runoff flows both in sheet fashion and in on-site stream channels westerly for approximately 3/4 miles to a tributary to Springbrook Creek. This tributary flows westerly along the southerly property line and then crosses under SR 167. Runoff continues flowing westerly for approximately 1/4 mile to Springbrook Creek. Springbrook Creek continues flowing northerly and eventually connects to the Black River and Green River (see downstream map in this section). Tasks Task 1: Study Area Definition and Maps This site has been analyzed using the available King County area maps. The included USGS map shows the site and downstream route. Additional maps include: an existing site ' map, site plan, stream map and wetlands map. Task 2: Resource Review ' The above listed maps were used to determine any potential flooding or erosion problems. No potential or existing problems were encountered using these documents. ' Task 3: Field Inspection ' The existing system was field inspected to the westerly portion of the site which includes the tributary to Springbrook Creek. The investigation revealed an entirely open storm systems (with the exception of the creek crossing under SR 167). See downstream analysis for general description for this existing system. As indicated in Task 2 above, no potential or existing problems were encountered using the available resource data. The downstream inspection revealed no evidence of constrictions, lack of capacity, flooding, overtopping, scouring or sedimentation. No evidence of significant destruction of aquatic habitat or organisms were observed. Weather conditions were sunny on August 14, 1997. ' Task 4: Drainage System Description and Problem Screening ' As indicated above, no potential or existing problems were encountered during the downstream investigation and/or problem screening. ' Task 5: Mitigation ' No potential or existing downstream problems were encountered during this analysis. The proposed multi-family project should not adversely impact the downstream system. Core Requirements ' 1 . This site will discharge at the natural locations which are the existing wetlands located along the westerly portion of the developed site. 2. The off-site system has been analyzed and is discussed above in the downstream analysis. 3. The runoff from this site will discharge to the natural locations as described in item 1 above. Detention is proposed for this project. Department of Fisheries standards ' were used to size the three individual detention vaults. These standards include releasing runoff at 50 percent of the pre-developed 2 year rate for the developed 2 year rate; 10 year pre-developed rate for the developed 10 year rate; and the 100 ' year pre-developed rate for the developed 100 year rate. 4. The proposed project will include storm tightlines from yard drains and building downspouts routed to catch basins and storm pipe. These pipe systems will be routed to three individual detention vaults. These vaults will discharge to three individual bio-filtration swales and level spreaders. The level spreaders will convey ,.5 sheet flow runoff into the downstream wetlands. 5. Temporary erosion control for this site will include two individual sedimentation ponds (basins A and B) and one sedimentation trap (basin Q. Silt fencing, "V" ditching and a construction entrances will also be included. 6. A maintenance and operations manual will be included in the final Technical Information Report. ' 7. A bond quantity form will be provided with the final Technical Information Report. tSpecial Requirements ' 1. The site appears to be located within the Green River drainage basin. 2. The site does not appear to lie within an existing Master Drainage Plan. ' 3. This site will be less than the 50 acre threshold requiring any conditions for a Master Drainage Plan. ' 4. This site will be designed in compliance with the 1990 King County Drainage Manual (1994 update) and DOE guidelines. 5. This site has more than 1 acre of impervious surface subject to vehicular use. The ' detention vaults have an average of 4.2 percent surface area of the sites total impervious surface areas (typically 1.5 percent is required in Renton). The vaults also have dead storage that matches or exceeds the volume for 1/3 of the 2 year ' developed storm. The project will not direct discharge to a regional facility. On- site detention and water quality is proposed. The site does appear to lie within 1 mile of a Class 2 stream. ' 6. This site has less than 5 acres of impervious vehicular surface. 7. This site does not lie within a closed depression. 8. This site will not use a lake, wetland or closed depression for peak rate runoff ' control. 9. The site does contain a Class 3 stream. The site does not abut a lake or closed ' depression. ' 10. This developed site will not contain or abut a Class 1 or 2 stream. 11. This site will not have an infiltration system. 12. A detailed soils report has been included in this report. Ilk 25 16 451� of ` IS 94 iril to /P}t, ra el� f , I �� pi .� BHi •h. ••�� 1 I I • a-�Q J� -1 J� .u, 1 1 it 36 eMm 17 I asbj •,� ' °ff ev 1 I •-' r .t L h y �a k. / QI D _.._.... - '• �� r Bit �d. HAYESloll 456 I 'Theater. .,. � 1; .. .1 � 1, •� r t 1 -- - ) '• U. way '^ •-}� . `. loss Ix Ub12 rien PIrk � •11�� (Trail ter _ W � • , DOWNSTREAM MAP�r' � ... � ,�� -�' -- -,•1�1•�I, .: . ��,• � _�'Ih( I1 I gin- _•_ \ \ \ �� I ,-� . 1 IV. Retention - Detention Analysis The site has been designed to collect runoff from the entire developed area. Runoff will be conveyed via yard drains, catch basins and storm pipe to three individual detention vault systems. Two of the vault systems are split to allow for sanitary sewer building service. From there runoff will be routed to three individual bio-filtration swales and level spreaders. The site has been designed using both the 1990 King County (1994 update) drainage manual and the DOE drainage manual. Department of Fisheries has review the project and has required additional detention control for the project. Each detention facility has been sized to store the developed 2, 10 and 100 year storm events. Each control riser located in the vaults will release the developed flows at 50 percent of the existing 2 year, the existing 10 year and the existing 100 year rates. The detention vaults have additional measures to provide water quality. The vaults each have minimum surface area and dead storage. The average surface areas for the vaults are 4.2 percent of the total sites impervious areas. The dead storage in each vault is equal or greater than 1/3 of the 2 year developed storm volume. 1 r L)eSiqn Ta blot 'Roeo - Glaoie reek 9718 Basin A ===================================================================== GA";ZN SJMMAR� 6��IN i� � A20 �AME � �e�e�u�ed � J Year 6BUH METH_qD0L06Y TDTAL ()REA I ­ 72 Ac;res Ell ASEFLOW, - f� RAINFALL �YPE . . . ' � TYPElA P E R V IM� N� PRECIPITATION . . . . � 2 �9O i�oMao A�EA � ' � 1 .�8 Acr*a � 'D4 Aor�e ~~ TIME INTERVAL 10 '00 mln CN 9' . 00 T[ ' �7 in9 ABSTRACTION COEFF : 0 '20 ToReach - Sheet L : 110 '00 no:0- 1500 o2yr ` 2 '00 e- O .OSOO impToReaoh - She��-" 150 .00 2 '0C C ' 0 ' 1000 impTu�ea�� - Channel L ' 300 .00 kc . 42 .00 s. 0 . 1-000 N� PEAK RATE7 1 '77 ofs VOL : 0 '67 Ao-ft TIME : 470 min BASIN ID : A100 NAME : Develnred �OO year METHODOLOGY l� m� TOTAL AREA ' ' . ' . ' . / 3 '72 Acres BASEFL0WS : 0 '00 cfs RAINFALL TYPE ' TYP Ell A PERV IMP PRECIPITATION . . � 3 .9O inches AREA ' ' � 1 .68 Acres - .04 Acreo TIME INTERVAL . . ' � 10 -00 min CN ' . ' . � 66 .00 98 '00 TC . 9 .27 min 1 . 49 min ABSTRACTION COEFF - 0 .20 ToReach - Sheet. L : 110 .00 no * 0 . 1500 p2yr . 2 '00 a, 0 '0500 w� imoToReaoh - Sheet L : 150 '00 no:0 .0110 p2yr : 2 '00 a : 0 ' I000 impToReach - Channel L: 300 '00 kc :42 .00 s, 0 '1000 PEAK RATE : 2 '55 ofs VOL : 0 .97 Ac-ft TIME: 470 min BASIN ID: A3 NAME ; Developed 2 year SBUH METHODOLOGY TOTAL AREA ' ' ' . . ' ' 3 '72 Acres BA5EFLOW5: O 'OO ofa n� RAINFALL TYPE ' ' ' ' TYPE1A PERV IMP PRECIPZTATION ' . ' ' : 2 .00 inch-es AREA , —� 1 '68 Acres 2 '04 Acres TIME INTERVAL ' ' . ' 10 '00 min CN . . . . : 86 '00 98 '00 TC ' ' ' . , 9 '27 min 1 '49 min ABSTRACTION COEFF : 0 '20 ToReach - Sheet L , 110 '00 no .0 '1500 p2yr : 2 '00 s:O '05OO impToReach - Sheet L : 150 '00 ns :0 '0110 p3yr : 2 '00 s:0 '1000 lmpTcReach - Channel L . 300 '00 hc:42 '00 s; 0 ' 1000 PEAK RATE 1 '0­1 cf� VOL : 0 '42 ft TIM 47O mir -- � �� 2/98 8 n�i-Iee. esi�� Znc paqe � T�lbo� �oa'2 - 8l a�ier Croek U� 9719 8a�in � BASIN' SUMMARY �N 8A�IN ZO : aI0 'NAME ' 1O voar U� SBUH METHODOL0�Y �OTAL AREA . 3 , 72 Acres BASEFLOW6' 0 .O0 cfo RAINFALL TYPE ' . . ' � TYpElA PERV IMP PRECIPZTATION . . . . . 2 0 es AREA 72 Acraa O .DD Acres TIME INTERVAL . . . lO 'OO min CK ' ' . ' 81 .00 O 'OO TC . ' ' ' ' 44 '71 min 0 .00 min ABSTRACTION COEFF ' O '2O ' TcReach - c'heet L 300 . 30 0 . 40O0 �2y 2 .00 a � D .O7S5 TcReaoh - (-:',ha1low 1 285 '01"') ks :3 '00 a-0 '0735 PEAK RATE : O .56 ofs VOL : 0 .38 Ac-ft TTME : 490 min BASIN ID: a1OO NAME : Existing lOO yea,,, '7�BUH METHODOLOGY TOTAL AREA � 3 '72 Acres 8ASEFL0W5: 0 '00 ofo ' ' ' . . ' ' RAINFALL TYPE . . ' ' ; TYPElA PERV IMP PRECTPITATION . . . . ; 3 '90 inches AREA . . : 3 .72 Acres 0 .00 Acres �N TIME ZNTERVAL . ' ' : 10 '00 min CN ' ' ' . . 81 '00 O 'OO U� TC . ' ' . 44 .71 min 0 .00 min ABSTRACTION C0EFF ; 0 '20 ToReaoh - Sheet L : 300 .00 ns:O '4000 p2yr . 2 .80 o: 0 .0735 N� TcReaoh - Shallow L : 285 '00 ko:3 '00 e:0 '0735 PEAK RATE : 1 '01 ofo VOL : 0 '63 Ao-ft TIME : 490 min BASIN ID: a2 NAME: Existing 2 year SBUH METHODOLOGY TOTAL AREA ' ' ' ' ' ' 3 '72 Acres BASEFLOWS: 0 '00 cfs RAINFALL TYPE ' ' ' ' : TYPE1A PERV IMP PRECIPITATION . ' ' ' : 2 .00 inches AREA . . : 3 '72 Acres 0 '00 Acres TIME INTERVAL ' ' . . : 10 '00 min CN ' ' ' ' 81 '00 0 '01) TC ' ' ' ' : 44 '71 min 0 '00 min ABSTRACTION COEFF: 0 -20 TcReech - Sheet L : 300 '00 ns:0 '4000 p2yr : 2 '00 a: 0 '0735 TcReaoh - Shallow L: 286 '00 ko:3 '00 s :0 '0735 PEAK RATE : 0 '20 cfa VOL : 0 ' 19 An-ft TIME: 540 min - �� / �C _ T":>:li tee'. 1 ">' _)e,—L q, _ n, l7c�C_ i i:.E?o Road Giaciei Cr?eik 97i8 Bashi A HYDROGRAPH SUMMARY r'EAK' T!ME VOLUME HYD RUNOFF Off. OF Cont.viu NUM RATE P'EAf': HYC>RO ,area cfs m,i Tl . Cf\Acr't Acres 9. '==0 .202v 540 ^� �8164�cf^====l3 ,72- �x�ST• 7- y2 21 0 . 546 490 1670 cf .72 " 1G 3 1 .007 490 27516 cf 3 .72 100 4 1 .090 470 18317 cf 3 .72 D IZ-v. Z y2 5 1 .760 470 29380 cf 3 .7 ' 10 6 2 .547 470 42120 cf 3 .72 10.0 c; 0 - i O1 540 !.082 f 7 . 72 50 7, rzxiST 2 y2 9 0 .360 470 6045 cf 3 .72 1?1:-V 10 y2 - F1't. r�s.nr� S1c�c. 11 0 . 101 540 4078 cf 3 .72 50 11,7,, F-KKi '- Z y2 _ (Si 0 SL..r"tr 12 0 .533 500 16702 cf 3 .7_' r_k►Sr to �i`t y ,, 13 2 .474 480 42119 cf 3 _72 0 C L., toy 18 0 . 101 1450 13532 cf 3 .72 vh v,., 19 0 .380 790 23030 cf 3 .72 20 1 .011 550 35741 cf 3 . 72 l 12/98 -• - r4 diii i.0 tTjcli:;e-rlr;, Des ''f: YIC. 4 Road 9718 8as y STGR(,n':- STPU`'TURT: RECTANCGU"AR VAU i IC- No . V.I. Description: Vault i L.erigti _80 . )G ft . Wi t.h: 2b .00 "_ . : ds : C0C� A� Tfrnlln- n vr L,01-7r. o S 1^Pr-.fz V I ate's = 7.0 4- A r- I a1c c - I/w-,r--2VloL j S F Sv(?/r-Acr. 2C Co, Vnti. �-r iS i�o� xZo' = 3Goc Sr o�c, CVl,-W, = 4.0 .70 '"P� t � 2 Cf= , 'rg 2 y �443 2�G:Q , o rr��7 S`-e-4 ' 7ZCIO G� 01& _ wi 12/98 S : -3 : 54 arr acif s c Er.q . ^.et:r- �.nQ De�1_ir-1 :nC' T8.1b oac! - Glacier CreF-- 9718 S a s 1, DISCHARGE STRUC Tl,;RE LILT COMBINATION DI=CHARGE Description : Combo 1 Structure: 01 Struct.ura : Structure : RI Structure : StrUCture : MULTIPLE ORIFICE ID No . 01 Description: Orifice 1 outlet Elev = 108 .00 Elev.- 106 .00 ft Orifice Diameter : 1 . 4180 in . RISER DISCHARGE ID No . R1 De crypt.ion : 1 Riser Diameter ( in ). 12 .00 elev : 112 . 10 ft Weir Cc;effici.ent . . . : 9 .739 height : 113 .00 ft Orif Coefficient 3 .782 increm. : 0 . 10 ft — i21 f .� r �((I ��iGjc_C _. .{1r.��Yjr � - - - i :r: iC{c 6 `a 710 R LEVE! F00L Tz�3i.._ SUMMARY CT CRAG; (--------OESCRIP710N---------) (cfsi (cfs? --id- --id- (-STAGE) id VOL (cf) 50%ez2yr-dev2yr .............. 0.1C 1.09 V1 -- 01 111.44 18 12377.43 cf ezl0yr-devlOyr ............... 0.55 1.77 V1 C! 112.19 19 15074.19 cf ez100yr-dev100yr ............. 1.01 2.55 V1 C1 112.30 20 15493.32 cf Match Inflow Storage Disch Peak Peak Peak Description Peak Peak ID ID P Stage Volume Out 50%ex2yr-dev2yr 0 . 10 1 . 01 Vl 01 111 . 44 12377 0 . 10 exl0yr-devl0yr 0 . 55 1 . 77 Vi C1 112 . 19 15074 0 . 38 exl00yr-dev100yr 1 . 01 2 . 55 Vl Cl 112 . 30 15493 1 . 01 2 1�'�r�� ) . LF 17 an, rc'... ...s =r;c'1r'I¢� r_n�t i18:�?C!% n _ Via, Ta b o t R'Ja.c1 - G1c%i ?eii 97i8 Basin B BASIN SUMMARY ASIN D B10 NAME : fl')ev;.1ooed -0 /ea. S3JH M=.THODOLOG Y TOTAL AREA . . . . . . . 6 . 31 AC-r '. 8ASEFL0WS 0 .00 cf RAINFALL TYPE _ P^_� PE_ R;,, PRECIF''ITATI0IR 30 • T:Ches r'S.REA .i .0o Acre 3 TIME INTERVAL . . . . 10 .00 mir; CN . . . . - 86 .00 96 .00 TC . . . . • 1.4 .70 min 1 .77 min ABSTRACTION COEFF : O .20 TcReach - Sheet 175 ,00 ns : 0 . 1S00 p2vr - 2 .00 s- 0 .0400 impTcReach - Sheet _ 150 .00 ns 0 .0110 p2yr - 21 .00 s 0 .060,' impTcReach - Channel L : 2SO .00 kc : 42 .00 . 0 .0600 PEAK RATE : 2 .83 cfs VOA : 1 . 12 AC-ft IM`= 480 min BASIN ID: B100 NAME - Developed 100 year S'D-BU i METHODOLOGY Y TOTAL AREA . . . . . . . : 6 . 31 Acres BASEFLnwS : 0 .00 Cfs RAINFALL TYPE . . . . : T',';"'-1.`, PEF;V IMP PRECIPITATION . . . . ; 3 .90 inches AREA _ : 3 .08 Acres 3 .?3 Acres TIME INTERVAL . . , . 1.0 .00 min CN . . . . : 86 .00 98 .00 rC . . . . : 14 .70 min 1 .77 min ABSTRACTION COEFF : 0 .20 TcReach - Sheet L. - 175 ,00 ns : 0 . 1500 p2vr . 2 .00 s: 0 .0400 impTcReach - Sheet L : 150 .00 ns: 0 .0110 p2yr - 2 .00 s : 0 .060O impTcReach - Channel L : 250 .00 kc . 42 .00 s -0 .0600 PEAK RATE : 4 . 10 cfs VOL : 1 .62 Ac-ft TIME= 480 min BASIN ID: B2 NAME : Developed 2 year SBUH METHODOLOGY TOTAL AREA . . 6 .31 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION . . . . : 2 .00 inches AREA . . : 3 .08 Acres 3 .23 Acres TIME INTERVAL . . . . : 10 .00 min CN . . . . : 86 .00 98 .00 TC . . . . : 14 .70 min 1 .77 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet. L: 175 .00 ns :0 . 1S00 p2yr : 2 .00 s:0 .0400 impTcReach - Sheet L : 150 .00 ns :0 .0110 D2yr : 2 .00 s:0 .0600 impTcReach - Channel L " 250 .00 kc : 42 .00 s: 0 .0600 PEA1< RATE : 1 .73 cfs VOL : 0 .70 Ac-ft TIME : 470 min 1?/98 9 45 : 47 .an'i Pacific Encineari`-�c; Design Inc Talbot Boa:! GIa.cLe'i 9710 BASIS! SUMMARY ` SASIN ID : 'D1V SSUH MIETHODOLOGY TOTAL ;1REA . , . . . . . • 6 .�>1 ^ 'l = o 'CFL..OI•J'�,: 0 .O^ c is- RAINFALL.- TYPE . T Y P E 1 A. RERV IMP PRECIPITATION . . . . 2 . 0 incI AREA . . 6 . 31 Acres 0 .00 Acres TIME INTERVAL . . . . 10 .00 mill. CN . . . . . 81 .00 0 .00 TC . . . . 45 .50 min 0 .00 min ABSTRACTION COEFF: 0 .20 TcReach - Sheet L : 300 .00 ns-- :0 . 4000 Q'yr : 2 .00 s :0 .0654 TcReach - Shallow L : 220 .00 ks : 3 .00 s:0 .0654 PEAK RATE : 0 .92 cfs VOL : 0 .65 Ac-ft. TIME : 490 min BASIN ID : b100 NAME : Existing 100 year S> uFI METHODOLOGY TOTAL AREA . . 6 .31 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE . . . . TYPEIA PERV IMP _ PRECIPITATION . . . . : 3 .90 inches AREA . . : 6 .31 Acres 0 .00 Acre: TIME INTERVAL . . . . • 10 .00 min CN . . . . . 81 .00 0 .00 TC . . . . : 45 .50 min 0 .00 min ABSTRACTION COEFF : 0 .20 TcReach - Sheet L : 300 .00 ns:0 .4000 p2lyr : 2 .00 s:0 .0654 TcReach - Shallow L : 220 .00 ks: 3 .00 s:0 .0654 PEAS: RATE : 1 .70 cfs VOL : 1 .07 Ac-ft TIME: 490 min BASIN ID : b2 NAME: Existing 2 year SBUH METHODOLOGY TOTAL AREA . . . . . . . : 6 .31 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE . . . . - TYPEIA PERV IMP PRECIPITATION . . . . : 2 .00 inches AREA . . : 6 .31 Acres 0 .00 Acres TIME INTERVAL . . . . : 10 .00 min CN . . . , : 81 .00 0 .00 TC . . . . : 45 .50 min 0 .00 min ABSTRACTION COEFF : 0 .20 TcReach - Sheet L: 300 .00 ns:0 .4000 p2yr : 2 .00 s:0 .0E,54 TcReach - Shallow L : 220 .00 ks:3 .00 s:0 .0654 PEAK RATE : 0 .34 cfs VOL : 0 .32 Ac-ft TIME : 540 min 2,/24/9 8 4 S D r7-i P a c if " c E-gineer i -)e �c;;'. Inc c Q 1�1 t Ro G I a c i e c-e 97 1 Bain CS HYDROGRAPH SUMMARY PEAK TIME V 0)LU M rz- HYD RUNOFF 0 F 0 F C,on tv i b NUM RATE PEAK HYDRO A r e a, cf s min . c f\AcF Ir- Acre!-: 1 0 .342 S40 13847 of 6 .31 flklS-r Z. Wl 2 0 .910 490 28336 cf 6 .3:1 i 10 3 1 .695 490 46674 c.f.. 6 . 1 100 I , 4 -1 -�4 470 30296 of 6 .31 or v Z s 8 480 489:)3 c f 6 .31 10 61 4 . 102, 480 70434 of 6 .31 100 8 0 .171 540 6924 of 6 .31 50*7r, rz-I';-)-- 9 0 3998 c f Q 11 0 . 170 540 6920 of 6 .31 I;L c7o q)O Sklftil 12 0 .895 Soo 28333 of 6 .3 1 f V<15 10 `/(Z 13 4 .097 480 70431 cf 6 .31. v 18 0 . 171 1450 2 7 5 7 c:f -11, VALL;r CAA;71 (--t-� 19 0 .646 790 39344 of 6 .3I 20 1 .771, 550 CS 0 7116 c f 6 ,31 i 98 i-j . 4E i+�. ffl 11 �' c `n riee.'r T; 8 9718 L aJi r! 8 --TGRAGL T r � ,Ti,_r'71 ECTA��f�Ul_ftR VAULT �•,•''. Description : Vault kcric;th ' 170 .00 Ft "A cit h " .00 ;+ voicis 1 .C?C 0 � `7o Cry )M�f..-2 vi o�,.,S 140 -7 S� S A �/I�wLT K F70 z�' �2�G S r- o I' ( wVL7 = 3, 0 I)3 rJ Lcr�J G)G r t� _ /12.%9 4S 4 8. am ^=r-'i `ic^,Er;L_�;.i.T1ae i T-,L� De Cjn Inc: _ 3Qe 9718 S Talbot- Road 1a.cier C,i-eef., 8auin 8 DT'.-CHARGE STRUCTURE Lis i COMBINATION DISCHARGE ID 'N0 . C2' Description : Combo ::: Structt.tre : 02 5-�tr-u.c:tu.ra. Structure, : R2 Structure : Structure : MULTIPLE ORIFICE ID No . 0 Description : Orifice 2 Outlet Elev : 104 .00 Elev : 102 .00 ft Orifice Diameter : 1 6992 in . RISER DISCHARGE ID No . Re, Description: Riser 2 Riser Diameter ( in ) - 1 1 .00 elev: 109 .50 ft Weir Coefficient . . . "• 9 .739 height : 1.10 . 00 ft Ur if Coefficient. . . . - 3 .782 iricrem: 0 . 10 ft. "1/1-1/98 9 . 4: . 4 e�,,C.if 7 .. t:i , ;� _ 971�s ,i, :; riq Des r ;7 ; , Taibot F2oac. Glacier Creek Basin 8 i_rVSL P001_uTA8LE SUMMRRY-�=�-+_ MATCH INFLOW -STO- -DIS- (-PEAK-) STORAGE (--------DESCRiPTIO�---------> (cfs) (c`s) --id- --id- (-STAGE) id VOL (cf) SO:ex2yr-aev2yr .............. =0.171.73== =V202===108.77 18 20255.56 cf ex110yr-dev1Oyr 0.92 2.83 V2 C2 109.63 19 23914.98 cf ex100yr-dev100yr 1.70 4.10 V2 C2 109.80 20 24642.41 cf Match Inflow Storage Disch Peak Peak Peak Description Peak Peak ID ID Stage Volume Out 50%ex2yr-dev2yr 0 . 17 1 . 73 V2 02 108 . 77 20256 0. 17 iexlOyr-devlOyr 0 . 92 2 . 83 V2 C2 109 . 63 23915 0 . 65 ex100yr-dev100yr 1 . 70 4 . 10 V2 C2 109 . 80 24642 1 . 78 /1.. /98 10 1 19: Derr; Pac1LiC Engl 'neerinci _ =s_qn _rc T6.1bot Road aC1. ��. 9718 Basin C BASIN __-JJMMARY BASIN ID • C10 ^."sic c:1 r_. 10 VE. SBU " METHODOLOGY TOTAL AREA . . . . . . . . _ . 3 Acres 3ASEFL0WS 0 ,00 f:_ RAINFALL. TYr E TYPEIA P;ER'ti' PRECIPITATION . . . . ' 2 .90 iric:hes AREA . . = 1 . 15 Acres 0 .98 Acre TIME INTERVAL_ . . . . : 1.0 .00 min CN 86 .00 98 .00 TC: . . . . 16 . 11 min 0 .93 mi-n ABSTRACTION COEFF : 0 .20 IcReach - Sheet L : 170 .00 ne-0 . 1500 p2yr 2 .00 s , 0 .0300 impTcReach - Sheet L : 100 .00 ns :0 .0110 p2yr : 2 .00 s:0 .0700 PEAK: RATE : 0 .92 cfs VOL : 0 .37 Ac-ft TIME , 480 min -•i- BASIN ID ' C100 NAME : Developed 100 ye:� SBUH METHODOLOGY TO AL AREA . . . . . . . 2 . 1C- Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE TYPEIA PERV IMP PRECIPITATION . . . . : 3 .90 inches AREA . . - 1 . 15 Acres 0 .98 Acres - TIME INTERVAL . . . . : 10 .00 min CN 86 .00 9101 .00 TC . 35 .31 m., n 0 93 rr,in ABSTRACTION COEFF - 0 .20 TcReach - Sheet L : 170 .00 ns:0 .4000 a2yr : 2 .00 s: 0 .0300 impTcReach - Sheet L : 100 .00 ns:0 .0110 p2yr : 2 .00 3 : 0 .070O PEAT; RATE: 1 .21 cfs 'VIOL : O .53 Ac-ft TIME : 480 min BASIN ID : C2 NAME : Developed 2 year SBUH METHODOLOGY TOTAL AREA . . . . . . . : 2 . 13 Acres BASEFLOWS: 0 .00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION . . . . : 2 .00 inches AREA - : 1 . 15 Acres 0 .98 Acres TIME INTERVAL . . . . = 10 .00 min CN . . . . . 86 .00 98 .00 TC . . . . : 16 . 11 min 0 .93 min ABSTRACTION COEFF : 0 .20 TcReach Sheet L : 170 .00 ns:0 . 1500 p2yr : 2 .00 s:0 .0300 impTcReach - Sheet L : 100 .00 ns:0 .0110 p2yr . 2 .00 s:0 .0700 PEAK RATE : 0 .55 cfs VOL: 0 .23 Ac-ft. TIME : 480 min BASIN ID : c10 NAME- Existing 10 year SBUH METHODOLOGY TOTAL AREA . . 2 . 13 Acres BASEFLOWS : 0 .00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION . . . . - 2 .90 inches AREA . . : 2 . 13 Acres 0 .00 Acres TIME INTERVAL_ 10 .00 min CN . , . . , 81 .00 0 .00 TC . . . . 27 .7'? min 0 .00 rn .ri ABSTRACTION COEFF: 0 .20 TcReach - Sheet L : ?45 .00 ns- 0 .4000 a2yr : 21 .00 s:0 .1140 PEAK RATE : 0 .38 cfs VOL: 0 .22 AC:'-ft TIME : 490 min 121/9R 10 am Pa if 1C E,rgi n•ee - r'(-! 'De: Talbot Road Glacier Creek g718 r BASIN S.!MMARY BASIN ID : 01-00 'NAME E;.L_ , _nq 1 0 year SBUH METHODOLOGY TOTAL AREA . . . . . . = : 1'- Ac) e, 3ASEFLOWS - C 0 CJ ^ RAINFALL TYPE . TYPElA PERV Iiir PRECIPITATION . . . . • - 0 inches AREA . . • 2 . 13 'scree: 0 _00 Acre;- TIME INTERVAL . . . . 10 .00 min CN . . . . 31 .00 0 .00 TC . . . . 27 .73 min 0 .00 min AB5TRACTION COEFF : 0 .20 TcReach - Sheet L : 245 .00 ris:0 .4000 P2yr- : 2 .00 s: O . 1140 PEAK RATE : 0 .6% cfs VOL : 0 .36 Ac-ft TIME : 490 min BASIN ID : c2 NAME : Existing 2 year SBUH METHODOLOGY IOTAL AIR E:A . . . . . . . : 2 . 13 Acres BASEFLOWS : 0 .00 cfs RAINFALL TYPE . . . . : TYPEIA PERV IMP PRECIPITATION — . : 2 .00 inches AREA — : 2 . 13 Acres 0 .00 Acres TIME INTERVAL . . . . : 10 .00 min CN . . . . 81 .00 0 .00 TC, . . . . • 27 .73 min 0 .00 min ABSTRACTION COEFF ' 0 .20 TcReach - Sheet 245 .00 ns: 0 .4000 P2yr : 2 .00 s: 0 . 1140 PEAK RATE : 0 . 14 cfs VOL : 0 . 13. Ac-ft TIME : 490 min 2 4 98 4 2-2 _'5 nffi Yuciflf..... n�l.nee r q Des-' q ', T1-1(: ialb:..` Rcad, r 3c,ieY r` ee"r 971a d a.r C HY7ROiaRAP1-?^S,UMPIFI;'.;Y PEAK TME VOLUME HYD RUNOFF OF 0 F Contr il.D NUM RATE PEAK HYDRO Area cfs mi r, . cf\AcFt Acre:: 0 . 144 -490� 4674 cf 2 . 13 rklSi Z �1rZ 2' 0 .37c 490 9565 cf ? 10 3 0 .684 490 15755 ct 2 . 1 10Q 4 0 .552 480 9856 cf 2 .13 0r.✓ Z C. 0 .916 480 16077 cf 2 . 13 IG 6 1 .210 480 23291 cf 2 . 13 Ida u 0 .072 4' J 233, u _ . i S G 77c `y�'' Z 9 0 . 182 480 3253 cf 2 . 13 Ih o�v 10 b2 �"�� Ste. 1 i 0 .068 500 2335 cf z' . 13 ;50 °7e r kIS-r Z y2 fi 12 0 .368 490 9563 cf 2 . 13 FcklS't 10 ` Z 13 1 . 192 480 23291 c i-, 2 . 13 0C v. ►co '-jrz- 18 0 .072 1450 8954 cf 2 . 13 Vt L CT 19 0 .261 670 14767 cf 2 . 13 710 0 .690 530 21.927 cf 2 . 13 l .2/ 12/98 10 = 1S : 20 rjrl :`c'""� i r;c ;.%d._E. lai of lRoad, Glaciev CYeel 97io B a _n C. STOFFZZAGE STRUCTURE LIST RECTANGULAR VAU _7 IC, I 4 o . V? Description: Vaunt ?�engLh : 160 .00 1`t . Widtl'1 • ls .00 i t . voids : 1 .0100 1 '70 c/j-, In1crrcvia%Aj = 4Z -7 Sf- Sv2r-Aca Atcf:-h, V�l.7- IS Igo " u ►�� --4oa Sr- ai4 CVAI/Lrr Is '7o 1^, I), QEV6,1,oe6, 7 172 _ 3-Z Cr- C6--, rjrA-,� S-rtrLA r, 2/12/9" 10 ' 1r 20 affi rya lf.w t- E . -f I i_ia,er 11�.`.'i D�.•J J,SkiI 1r.1. Y �-�` r Talbot Roan Glacier Creek 4718 8asi n C DI�C-1HARGE: rTRUCTIIF::E. LIST COMBINATION D.L- :- ;ARGC. I^ No . C Description : Combo 3 �.tructure : 03 StrucLu're : Structure : R3 Structure' - Structure : MULTIPLE ORIFICE ID No . 03 Description : Orifice 3 ■ Outlet Elev : 100 .00 1� Elev = 98 .00 ft 'Orifice. Diamete)— : 1 .3184 in . RISER DISCHARGE TO No . R ' Descrimtion: Riser 3 Riser Diameter ( in ): 12 .00 elev : 102 .70 ft. Weir Coefficient . . . : 9 .739 height: 103 .00 ft. 01-if Coefficient . . . : 3 .782 increm : 0 . 10 ft 10: -r 20 Zffi tn. ac..: f C P a F Talbot. Read Glacier Creek 9718 Basin LEVEL FOOL TABLE SUMMARY MATCH INFLOW -STO- -O S- (-?cAK-> • STORAGE (--------DESCRIPTION---------> (cfs) (cfs) --id- --id- (-STAGE) id VIT. (cf) ----------------------------------------------------------------------------- 50%ez2yr-dev2yr .............. 0.07 0.55 V3 03 102.32 18 5557.98 cf ezl0yr-devl0yr ............... 0.38 0.92 V3 C3 102.76 19 6622.21 cf ez100yr-dev100y.. ............. 0.68 1.21 V3 C3 102.85 20 6848.66 of Match Inflow Storage Disch Peak Peak Peak Description Peak Peak ID ID Stage Volume Out 50%ex2yr-dev2yr 0 . 07 0 . 55 _ V3 03 102 . 32 5558 0. 07 exlOyr-devlOyr 0 . 38 0 . 92 V3 C3 102 . 76 6622 0 . 26 ex100yr-dev100yr 0 . 68 1 .21 V3 C3 102 . 85 6849 0 . 69 i I 1 1 KING COUNTY. W ASHINGTON, SURFACE WATER DESIGN MANUAL FIGURE 3.5.1C 2-YEAR 24-IIOUR ISOPLUVIALSco - - - - - 2. Y _ ( - _-- — nl Q 1wc. sl h 1!t`Jl 1 _ 4/ CV 2-YEAR 24-HOUR PRECIPITATION u ,.3.4--" ISOPLUVIALS OF 2-YEAR 24-HOUR TOTAL PRECIPITATION IN INCHES 0 1 2 3 4 3 6 7 8 Mlles 1/90 1:300,000 3.5.1-8 Ila Flo AWNII QV W- -16 I ON e _--a ®R i p EM Moll V. Conveyance Systems Analysis Pipe calculations have been included for the arch pipe over the existing stream between basins A and B. Department of Fisheries has requested that this be an open bottom pipe. This pipe has been sized to convey the developed 100 year upstream area (approximately 41 acres). It has been assumed that this basin would be developed to approximately 85 percent impervious area. The calculated 100 year flow for this area is approximately 32 cubic feet per second. The arch pipe was calculated using test flows for both an enclosed pipe (30 inch diameter) and open Swale (1 foot bottom with 3:1 side slopes). Both of these test calculations produced an approximately flow area of 4.5 square feet. The proposed arch pipe has on open area of 6.6 square feet (more if you count the trapezoidal area of the stream channel) which is approximately two times larger than the test calculations. Therefor, the proposed arch pipe should provide capacity for future upstream development with a safety factor of approximately 1.5 built in. r included. These calculations show flow depths and Bio-filtration Swale calculations are p velocities for 50 percent of the existing 2 year, the existing 10 year and developed 100 year. The on and off-site pipe calculations will be provided with the final plan engineering drawings. 1 i t 1 1 .� IJaleayl - I . • '••:�' . _�1L_ __.... :,. to • �I� '� W • • ` /�� r• / � • 1 on JI: rr I Q /Z • II• - l = i 1. WNW of M ' ' W _ :• •• I • ' I as I_ 97 a 9c We JaAej ` J I I LL • '� � it \ 1�— - • ;�� , 1f I 1, Vl7 �•` \• ! 3 7 N v c] o e cl 0 0 8 AS�E FL W 0 0.0 IOTAL AREA . — , 4 1 PR E C i P .TA I 0 N .,-40 I Ic he's A PRE A . 6 . 19 s 3'--. . l- A(.:rea, T T C, .0 0 m C N! . . . E-316 .0 C, 9 8 P-IE 11%,!TERVAI . . . . 5 .00 min ABSTRA:-TT.ON COEFF •, 0 .2c PEAK RATE : 32 .07 V 0 L .1 -1 .99 Ac-ft TIME 480 m-L-i .^ 2/26/98 ll L,2, 7 am Pacific Engineer DaoI" �r 9718 U� Basin O Upstream ===================================================================== HYDR0GRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF C0 Tit rib NUM RATE PEAK HYDRO Ar*a =� ofs min . cf\AcFt Acre� ============================================= 1 32 .072 480 522330 of 41 '30 32 '072 480 522330 of 41 '30 � 32 .072 48C 52233D cf 41 .30 4 32 '072 480 522330 of 41 .30 _ ' -�� 2/26/�8 ll � �2 � 38 �m �ec ��i� Enq�neerino Jo�i�s Irr a�;Je � Talbot Roa� a eek U� 9718 �asin st�-eam �FACH FUMMARY JITCH REAC|� ID Nu Djtc��1 /��L . -- [`i�oh L*nqth ; 74 OO f�� Dit�h �idth � � Q0 ft ' ' 3ide Slo��1 ' 3 .00 Ditch �loQe 0 'D��� ft/f� ' Side �lope2 � 3 .00 Contrib Bas � ~~ Mannlng� n � O 'O25D Dr Invert 0 '00 ft Dn W .S . Elev : 0 '0000 Num Steps 10 Trlb Area : 41 .30 Ac ' Design Flow 32 '07 ofs — Depth ` 1 .08 IF Vel 7 '06 Uoatream W .S . Elev : 0 '00 ft . PIPE REACH ID No . Pioe1 rrom - To : Pipe Diameter : 3 '0000 ft n ; 0 '0I20 Ripe Length 74 '0000 ft s : 0 .0288 Up invert ft down invert : ft Colleot-lon Area 41 .3000 Ao ' DeSign Flow 32 '0717 ofa Dagn Depth: 1 .05 ft Pipe Capacity 132 '2619 cfs ~� Design Vel 14 '6306 fps Travel Time : 0 '08 min Pipe Full Vel : 19 '2029 fps _ ��� ' Analysis & Desi,r: Solver, with Manning ' Er-1.uFti.or Over, � Ihannel - Uniform, low Wor ksheet. Name aib:�:. Ro��d 971t� �ST Gh1rC (=�L Z` �),d 't f7,��ti Comm�:nt Stream crossln�-,, - culvert ._:izinQ Solve For Full Flow Diameter Giv.rn ImPut Data : Elope . . . . . . . . . . . . . 0 .0290 ft/ft Mannino 's n . . . . . . . 0 .025 Discharce . . . . . . . 32 .00 cfs ComF.)uted Pesults : Full Flow Diameter . . . . . 2 .38 ft Full Flow Death . . . . . . , . 2 .38 ft, Velocity . . . . . . . . . . 7 . 17 fps. � Flow Area . . . . . . . . . 4 ,46 si` Critical Depth . 1 .'>4 ft Critical Slope . 0 .029 o ftr'f t. Percent Full 100 .00 Full Cana.city . . . . . 32 .00 cfw OMAX @ .94D . . . . . . . . 34 .42 cfs Froude Number . . . . . FULL Open Channel. Flow Moduli. . Version 3 .41 ( c ) 1993. ' Haestad Methods , Inc . ,= 37 8r«o :side Rd * l,iaterbury , Ct. 06705 Trapezoidal %Channel Analvsis & Oes;ar! Open Channel -- Unif orrr _;-oi-; work sheet Name: Talbot Road `:�718 Com, nt . cI-: Pine - st ea��; - -F-ST C h,L-C Art /A -r Foi- Bottom Width Giver, inDut. Data Left Side Slope . . 3 .00: 1 ( H.V ) Right Side Slope . 3 .00 : 1 ( !,, : V ) Manning 's n . 0 .025 Channel Slope . . . . 0 .0290 ft/ft Depth . . . . . . . . . . . . 1 .00 ft. Discharge . . . . . . . . 32 .00 cfs computed Results: Bottom Width . . . . 1 .56 ft. Velocity . . . . . . . . . 7 .02 fp.S Flow Area _ _ 4 .S6 sf Flow Top Width . . . 7 . 56 ft We._ted Perimeter-. 7 .88 ft Critical Depth . . . 1 .2S ft Critical Slope . . . 0 .0107 ft/ft Fronde Number . . . . FULL Open Channel Flow Module , Version 3 .41 ( c ) 1991 Haest.ad Methods , Inc . * 37 Brookside Rd =i� Waterbury , Ct 06708 Trapeze)1 d6;.i C 3i -,, ups c,r: Open Channel Unitorrri flour w,rikshes_:L Name : T.= lbot Road `-)718 Comment. �";rC� Pi g..• -- -tr �:arr, c,:,o•sLinc Solve For 7ent'r� TEST C M.(. 1��Z r[.G,. Given Input. Date: : Bottom Width . . . . . 1 .00 ft Left Side Slope . . 3 .00 : 1 (. PI :V ) Right Side Slope . 3 .00 : 1 ! H: `) j Manning 's n . . . . . . 0 .025 Channel Slope . . . . 0 .0290 ft/ft Discharge . . . . . . . . 32 .00 Cfs Computed Results : Depth . . . , . . . . , . . . 1 .07 ft Velocity . .. . - . . . . . 7 .06 fps Flow Area . . . . . . . . 4 . 4 sf Flow Top Width . . . 7 .44 ft. Wetted Perimeter . 7 .79 ft Critical Depth . . . 1 .32 ft Critical Slope . . . 0 .0107 ft./ft Froude Number . . . . FULL � d4 O;p�n Channel Flow Module , Version 3 .41 ( c ) 1.991 Haestad Methods , Inc . * 37 Brookside Rd * Waterbury , Ct 06708 Table 10/Conveyance Factors-Pipe Arch-Various Values of n Riveted and Corlix Pipe Arch ' A 11 Size,in. Area, Hydric. .012 .014 .016 .017 .018 .019 .020 .021 .024 .025 sq. Radius, Span Rise 1t. 1t. ' 17 13 1.2 .311 69 59 52 49 46 44 42 40 35 33 21 15 1.7 .357 105 90 78 74 70 66 63 60 52 50 i y�l S 24 18 2.3 .415 157 135 118 111 105 99 94 90 79 75 i 28 20 -2.9 .458 212 182 159 150 141 134 127 121 106 102 35 24 4.4 .563 373 320 280 263 249 236 224 213 187 179 42 29 6.5 .689 627 537 470 442 418 396 376 358 313 301 49 33 8.4 .766 873 748 655 616 582 551 524 499 436 419 ' 57 38 11.3 .896 1300 1110 972 915 864 819 778 741 648 622 64 43 14.4.\ 1.021 1810 1550 1360 1280 1210 1150 1090 1040 907 871 71 47 17.4 1.109 2310 1980 1730 1630 1540 1460 1390 1320 1160 1110 77 52 21.3 1.232 3030 2600 2270 2140 2020 1910 1820 1730 1520 1450 83 57 25.6 1.359 3890 3340 2920 2750 2600 2460 2340 2220 1950 1870 Structural Plate Pipe Arch A R Size,In. Area, Hydric. .031 .032 .033 .034 .035 sq. Radius, Span Rise ft. ft. ' 67' 5'0" 24.7 1.389 1470 1430 1390 1340 1310 6T' 4'11" 26.6 1.431 1620 1570 1520 1480 1430 67" 5'8" 29.6 1.527 1880 1820 1770 1720 1670 6'11" 5'9" 32.0 1.585 2100 2020 1960 1900 1850 7'3" 5'11" 34.4 1.639 2290 2220 2150 2090 2030 7'9" 6'0" 36.8 ' 1.689 2500 2420 2350 2280 2220 811" 6'1" 39.3 1.739 2720 2640 2560 2480 2410 8'5" 6'3" 41.9 1.791 2960 2860 2780 2700 2620 8110" 6'4" 44.5 1.839 3200 3100 3010 2920 2840 AIN 9'3" 6'5" 47.2 1.888 3460 3350 3250 3150 3060 t 97' 6'6" 49.9 1.934 3710 3600 3490 3390 3290 9'11" 6'8" 52.7 1.9111 39110 3860 3740 3630 3530 10'3" 6'9" 55.6'- 2.029 4270 4140 4010 3890 3780 10,9" 6'10" 58.4 2.071 4550 4410 4270 4150 4030 11.1" 7'0" 61.4 2.117 4850 4700 4560 4420 4300 11'5" 7'1" 64.4 2.160 5160 5000 4850 4700 4570 11,9" 77' 67.5 2.205 5480 5310 5150 5000 4860 12'3" 7'3" 70.6 2.248 5810 5630 5460 5300 5140 127' 7'5" 73.8 2.291 6150 5960 5780 5610 5450 12'11" 7'6" 77.0 2.333 6490 6290 6100 5920 5750 13'1" 8'2" 83.1 2.457 7250 7030 6810 6610 6420 13.1" 8'4" 86.9 2.510 7690 7450 7230 7020 6810 13'11" 8'5" 90.3 2.551 8090 7830 7590 7370 7160 14'0" 87' 94.2 2.601 8540 8270 8020 7790 7560 ' 13'11' 9'5" 101.5,- 2.741 9530 9230 8950 8690 8440 14'3" 9'7" 105.7 2.794 10100 9740 9440 9170 8900 14'8' 9'8" 109.9 2.845 10600 10200 9940 9640 9370 14'11" 9'10" 114.2 2.896 11100 10800 10400 10100 9850 15'4" 10'0" 118.6 2.948 11700 11300 11000 10700 10400 ' 15'7" 10'2' 123.1 3.000 12300 11900 11500 11200 10900 16'1' 10'4" 127.6 3.050 12900 12500 12100 11700 11400 16'4" 10'6" 132.3 3.103 13500 13100 12700 12300 12000 16'9" 10'8" 136.9 3.152 14100 13700 13300 12900 12500 17'0" 10'10" 141.8 3.205 14800 14300 13900 13500 13100 17'3' 11'0" 146.7 3.257 15500 15000 14500 14100 13700 17'9" 11'2" 151.6 3.307 16100 15600 15200 14700 14300 18'0" 11'4" 156.7 3.360 16800 16300 15800 15400 14900 18'5" 11'6" 161.7 3.408 17600 17000 16500 16000 15500 18'8" 11'8" 167.0 3.461 18300 17700 17200 16700 16200 19'2" 11'9" 172.2 3.511 19100 18500 17900 17400 16900 19'5" 11'11" 177.6 3.563 19900 19200 18700 18100 17600 19'10" 12'1" 182.9 3.611 20600 20000 19400 18800 18300 20'1" 12'3" 188.5 3.663 21500 20800 20200 19600 19000 20'1' 12'6" 194.4 3.720 22400 21700 21000 20400 19800 20'10' 12'7" 199.7 3.764 23200 22400 21800 21100 20500 21'1" 12'9' 205.5 ' 3.816 24100 23300 22000 21900 21300 21'6" 12'11" 211.2 3.864 24900 24100 23400 22700 22100 2/24/98 9 1 -3 ncj e �'e' Roa d. e, K L 9718, Basin A or T V. t 0 00 1 t c d t 1-1 4 00 yt Side SIODCI Ditclh; Slope - 0 .01-00 ft/ft 3 0 IV) C c-- i b B Mannings -n 0 300 Dn Tnvext- Cal .00 ft Dn W .S . Elev , 0 .00001 um Ste;,-)s lG Trib Area : -72 Ac . Design Flow 2 .47 cts Depth 0 .27 ,"'t- V e- 1 .87 fps uPstrean: G .S . Elev , 0 .00 ft DITCH REACH ID No . 8 i o I Oyr GkOS i, Ditch Length - 200 .00 ft Ditcl-, Width . 4 .00 ft� >icie. Z:�ic)P(7,1 Uitch Slope . 0 .0100 vt/tt Side SloPe^ 31 .00 Contrib Bas : Mannings n : 0 .0300 Dn invert : 0 .00 ft Dn W .S . E1ev :0 .0000 Num. Steps 10 Trib Area. 3 .72 Ac . Design Flow 0 .S3 efs Depth 0 . 11 f"-- Vel 1 .09 fps Upstreari W .S . E.'A'.ev : 0 .00 "Zt DITCH REACH ID No . BioSO%2Y(?- Ditch Length : 200 .00 ft Ditch Width: 4 .00 ft. Side Slopel : 3 .00 Ditch Slope : 0 .0100 ft/ft Side Slope2 : 3 .00 Contrib Bas: Mannings n :0 .0300 Dn Invert : 0 .00 ft Dn W .S . Elev:0 .0000 Num Steps 10 Trib Area : 3 .72 Ac . Design Flow 0 . 10 cfs Depth 0 .04 ft 'reel 0 . 58 fps Upstream W .S . Elev, 0 .00 ft . ' 2'/_4/9a 4 18 =5 -Gr�11 ?=".' _n� ic�1:?r! C p•�Cie a boi R o a C. G aCiel. 9718 as n B REE.ACH SUMMARY DITCH REACH ID No . v;i.o100yry Ditch L e,nCth: 200 ..00 ft D C:h Width . 4 .00 t ,i.dc `Iopel _ ,00 DIt ,I S1c>p : ; .1 ftlf Side Slope2 .00 Contrib Bas: Mannings n :0 .0300 Dn Invert 0 .00 ft -)n W .S . Elev :0 .0000 Num Steps 10 Trib Area : 6 .31 Ac . Design Flow 4 . 10 cfs Depth 0 . "'O ft Vel -1 .78 tos Upstream W .S . Elev : 0 .00 ft . DITCH REACH ID No . BiolOvr GY)Si Ditch Length . 200 .00 tt Ditch Width ; 4 .00 tt Side Slopel 3 .00 Ditch Slope : 0 .0200 ft/ft Side Slope2 3 .00 Contrib Bas : Manning-s n . 0 .0300 Dn Invert 0 .00 ft. Dn W .S . E1ev :0 .0000 Num Steps . 10 Trib Area : 6 .31 Ac . Design Flow : 0 .90 cfs Depth 0 . 12 ft. Vel. 1 .65 fps Upstream W .S . Elev. 0 .00 ft . DITCH REACH ID No . Bio50 02 y2 r-kiST . Ditch Length: 200 .00 ft Ditch Width: 4 .00 ft Side Slopel : 3 .00 Ditch Slope: 0 .0200 ft/ft Side Slope2 : 3 .00 Contrib Bas: Mannings n :0 .0300 Dn Invert 1 0 .00 ft Dn W .S . E1ev: 0 .0000 Num Steps : 10 ' Trib Area : 6 .31 Ac . Design Flow : 0 .17 cfs Depth 0 .05 ft Vel 0 .89 fps Upstream W .S . Elev: 0 .00 ft . ._/24/`%8 4 22 315 '=III . ..'Paci-F J.c-Eng1 --tee-, 1 rig Des,yC^ i r.r- n !_�.• -- Ta ' .9718 Glacier Creek REACH SUMMARY ' DITCH REACH IO No , Bio1.00y-r- QGV- Ditch math- 200 .00 ft D:i,.r,h Width, + .00 ft Sid- Slopel 3 .00 Di t.ch ;lope, 0 .0050 ct/f t,; Side Slope2 3 .00 Contrib Bas: Mannings n : 0 .0300 Dr: Invert 0 .00 ft Dn W .S . Elev: 0 .0000 Num Steps 10 T,,-ib Area . 2 . 13 Ac . Design Flow 1 . 1.9 cfs Depth 0 .212 ft Vel 1 . 16 fps Upstream W .S . Elev : 0 .00 ft . DITCH REACH ID No . Bi olOyr rzk►ST• bit.0 1 Le.ngLh. e'_'00 .00 1 t witch, Width. 4 :00 i't. Side Slopel 3 .00 Ditch Slope: 0 .0050 1-t--/ft Side Slope2 3 .00 Contrib Sas: Mannings n : 0 .0300 Dn Invert : 0 .00 ft Dn W .S . Elev:0 .0000 Num Steps : 10 Trib Area: 2 . 13 Ac . Design Flow : 0 .37 cfs ' Depth 0 . 11 ft Vel 0 .77 fps Upstream W .S . �=1ev: 0 .00 ft- DITCH REACH ID No . Sio50 o2Y(Z M)OM Ditch Length: 200 .00 ft Ditch Width: 4 .00 ft Side Slopel : 3 .00 Ditch Slope : 0 .0050 ft/ft Side Slope2 : 3 .00 Contrib Ba.s: Mannings n :0 .0300 Dn Invert 1 0 .00 ft ' Dn W .S . Elev :0 .0000 Num Steps = 10 Trib Area : 2 . 13 Ac . Design Flow 0 .07 cfs Depth 0 .04 ft Vel 0 . 41 fps Upstream W .S . Elev : 0 .00 ft . V. Special Reports and Studies The soils report prepared by GEOTECH Consultants is included in this section. GEOTECH April 8 1997 CONSULTANTS, INC. ' 13256 N.E.20th St.(Northup Way).Spite 16 J N 97100 Bellevue.WA 98005 (206)747.5618 ' FAX 747-8561 SEB, Incorporated 4109 Bridgeport Way West, Suite C Tacoma, Washington 98466 Attention: Steve Berg Subject: Geotechnical Engineering Study Talbot Road Apartments Talbot Road South at South 55th Street (South 192nd Street) Renton, Washington Dear Mr. Berg- We are pleased to present this geotechnical engineering report for the Talbot Road Apartments to be constructed in Renton, Washington. The scope of our work consisted of exploring site surface and subsurface conditions, and then developing this report to provide recommendations for general earthwork and design criteria for foundations, retaining walls, and pavements. You authorized our work by accepting our proposal, P-4163, dated March 7, 1997. The subsurface conditions of the proposed building site were explored with twenty test pits that encountered 6 to 18 inches of topsoil, overlying native, weathered silty sands with varying amounts of gravel. The native sands typically became medium-dense at depths of 2-1/2 to 4-1/2 feet, and became dense to very dense between 4 and 8 feet. Slight to moderate groundwater was encountered perched above the medium dense soils.in all of the test pits. The proposed buildings and bridges can be supported by conventional footings bearing on the medium-dense, native soils or on structural fill placed above these competent soils. The presence ' of groundwater and wet soils will make site earthwork difficult and more costly than on a "typical" site in the Puget Sound area. Subsurface drains will be necessary along the upslope side of the site prior to starting the earthwork process. Other subsurface drainage measures will likely be ' needed depending on the planned final grades and the conditions encountered during earthwork. Due to the high silt content of the native soils, they are moisture sensitive and will be very difficult to grade. The high moisture content of the native, silty sands makes them useable as structural fill ' without substantial drying during hot, dry weather. This includes utility backfill. The native silt will not be useable as structural fill due to its low compacted strength. The costs associated with grading during wet weather will be substantially higher than those of grading operations undertaken in drier weather. Imported sandy fill will be required for structural fill if wet weather grading is attempted. ' - Y ' SEB, Incorporated JN 97100 April 8, 1997 Page 2 ' The attached report contains a discussion of the stud and our recommendations.P y m ndations. Please contact us, if there are any questions regarding this report or if we can be of further assistance during the ' design and construction phases of this project. ' Respectfully submitted, GEOTECH CONSULTANTS, INC. ' Marc R. McGinnis, P.E. Associate ' MRM:mmm 1 ' GEOTECH CONSULTAN-rS,INC. tGEOTECHNICAL ENGINEERING STUDY Talbot Road Apartments Talbot Road South at South 55th Street (South 192nd Street) Renton, Washington This report presents the findings and recommendations of our geotechnical engineering study for the site of the proposed apartment complex in Renton, Washington. The Vicinity Map, Plate 1, illustrates the general location of the site. We were provided with a Concept Site Plan developed by Casey Group Architects and dated December 26, 1996. This plan showed a portion of the site boundaries, general topographic information, the approximate outline of the "wetlands", and the proposed building locations. No final grades were indicated on the provided plan. We anticipate that the development will consist of more than 35 two-story townhouse and apartment buildings, in addition to a recreation building ' with a swimming pool. Much of the area around the buildings will be paved for driveways and parking. According to the plan, the main roadway will enter the development at the north end, in line with South 51 st Street. Bridges are proposed to cross the existing creeks to allow access to the southern portions of the site. ' SITE CONDITIONS Surface The large, rectangular-shaped parcel covers an area of approximately 12 acres immediately northwest of the intersection of Talbot Road South and South 55th Street, which is also shown on some maps as South 192nd Street. The property was undeveloped at the time of our field work. ' The site is divided by a west-flowing stream into a large northern section and a smaller southern section. A drainage ditch flows westward from a culvert beneath Talbot Road South in the northern section of the property. Another culvert empties onto the site from beneath Talbot Road ' South on the south section. Along the eastern side of the property is a ditch that contained standing water at the time of our field work. The surface of Talbot Road South slopes toward this ditch. A ditch containing a substantial amount of running water was noted along the south boundary of the site. The heavily-vegetated site was covered primarily with blackberry vines and other underbrush. A large grassy area was noted bordering Talbot Road South toward the center of the site. Numerous small to medium-sized deciduous trees, and a few larger deciduous and ' evergreen trees, are scattered around the property. The ground surface generally slopes about 10 percent towards the west-southwest with a ' maximum slope of about 20 percent. There were no observed steep slopes in proximity to the proposed development area. Most water from the upslope properties to the east flows to the site via the three 18-inch culverts that cross under Talbot Road South. During the heavy rains that ' occurred while we conducted our explorations, these culverts carried heavy flows directly onto the site. The northwest portion of the site is relatively flat and low-lying, with standing water observed during our explorations. ' Development surrounding the site is varied. Across Talbot Road South and South 55th Street are numerous single-family residences. The Summit Park townhomes and condominiums are situated east of the site at the 5100 block of Talbot Road South. The Talbot Park townhomes and GEOTECfI CONSULTANT'S.INC. t SEB, Incorporated JN 97100 April 8, 1997 Page 2 condominiums were' under construction to the northeast of the site at the 4700 block of Talbot Road South. The northern perimeter of the site abuts a single-family residence with several acres of pasture land. The western perimeter of the development area is defined entirely by a designated wetland. Subsurface The subsurface conditions were explored by excavating twenty test pits at the approximate ' locations shown on the Site Exploration Plan, Plate 2. The field exploration program was based upon the proposed construction and required design criteria, the site topography and access, the subsurface conditions revealed during excavation, the scope of work outlined in our proposal, and the time and budget constraints. The test pits were located by pacing from estimated property corners. The test pits were excavated on March 18 and 19, 1997 with a large tracked excavator. A geotechnical engineer from our staff observed the excavation process, logged the test pits, and obtained representative samples of the soil encountered. "Grab" samples of selected subsurface ' soil were collected from the backhoe bucket. The Test Pit Logs are attached to this report as Plates 3 through 12. The test pits generally encountered similar subsurface conditions in the areas that were explored. ' 6 to 18 inches of very moist, loose, silty sand topsoil were found beneath the surface vegetation, except in Test Pit 20, which exposed 2-1/2 feet of topsoil. Beneath the topsoil layer, the test pits all revealed very moist to wet, weathered, silty sands. The gravel content in these sands vaned and the native soils typically became medium-dense below a depth of 2-1/2 to 4-1/2 feet. The medium-dense soils were not encountered until a depth of 6 feet in Test Pit 20. The native sands often became less silty below depths of 4 to 6 feet and below a depth of 4 to 8 feet, they became dense. The final logs represent our interpretations of the field logs and laboratory tests. The stratification lines on the logs represent the approximate boundaries between soil types at the exploration locations. The actual transition between soil types may be gradual, and subsurface conditions can vary between exploration locations. The logs provide specific subsurface information only at the locations tested. The relative densities and moisture descriptions indicated on the test pit logs are interpretive descriptions based on the conditions observed during excavation. The compaction of backfill was not in the scope of our services. Loose soil will therefore be found in the area of the test pits. If this presents a problem, the backfill will need to be removed and replaced with structural fill during construction. ' Groundwater Perched groundwater seepage and wet soils were observed in all tests pits, which were conducted ' after several months of rainy weather. The seepage generally occurred at the interface between the loose and medium-dense, native soils. Seepage was also observed in sandier zones within the medium-dense to dense soils. The test pits were left open for only a short time period. Therefore, the seepage levels on the logs represent the location of transient water seepage and may not indicate the static groundwater level. It should be noted that groundwater levels vary seasonally with rainfall and other factors. We anticipate that groundwater could be found most, or ' GEOTECH CONSULTAINTS,IBC. SEB, Incorporated JN 97 April 8, 1997 e 3 Page 3 all, of the year in more permeable soil layers and between the near-surface, weathered soil and the underlying denser soil. CONCLUSIONS AND RECOMMENDATIONS General Based on our test pit information, the construction of the proposed apartment buildings on the subject site appears feasible from a geotechnical standpoint. The structures can be supported by conventional foundations bearing on the medium-dense to dense, weathered native soils. Depending on final grades, overexcavation may be required beneath the footings to expose competent, native soil. These overexcavations can be backfilled with structural fill or lean concrete. The main challenges during development of the site appear to be the substantial amount of subsurface water and the silty, moisture-sensitive nature of the native soils. The best way to reduce the impact of both of these factors on the site development is to conduct earthwork operations in the drier summer months. If grading activities take place in dry weather, when drying of the wetter soil by aeration is possible, the silty sands encountered in our test pits could be used as structural fill. This process will be slow, as each loose lift of soil would need to dry for one or more days before being compacted. Drying the excavated soils by aeration will be very difficult for utility trenches, which are usually excavated and backfilled relatively rapidly in short sections. It is important to note that reuse of the native soils as structural fill will be impossible during wet weather. Even if earthwork is conducted in dry weather, it could be necessary to import clean gravelly sands for structural fill and for the utility backfill in the areas of excessively wet soils. Wet soils could be dried chemically using kiln dust or cement during dry weather. This is also a slow process. Due to their low compacted strength, the native silts will not be useable as structural fill. We recommend installing subsurface interceptor, or "French", drains along the entire upslope edge of the proposed development area. These drains are intended to intercept subsurface water and should be installed early in the site clearing process. A typical detail for these drains is attached as Plate 15. Drains will also be needed where cuts of more than about 12 to 24 inches below the existing grade are planned for final grading. Additional subsurface drainage will be required where seepage is encountered in the development area. It is fairly common for some groundwater to bypass the upslope interceptor drain, requiring subsurface drains further downslope. Proper drainage behind all backfilled walls will be important, especially if they are adjacent to below-grade occupied spaces. Even if free-draining backfill is used behind the walls, it has been our experience that some seepage can be expected through the walls in the future if real waterproofing, such as bentonite panels, is not used. Footing drains must be well- constructed, and should be built using PVC pipe for best long-term performance and easiest maintenance. Drainage along the edge of Talbot Road South appears fairly poor. The eastern ditch does not move water very well and should be sloped to drain better, then it should be lined or culverted, to minimize the amount of water that will percolate into the underlying soils. One existing culvert in the central portion of the site is planned to be redirected so as not to discharge onto the proposed building area. There is another culvert near the southeast corner of the site that is not shown on the provided plan that will need to be handled in a similar manner. GEOTECH CONSULTANTS,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 4 When wet, the silty*native soils are subject to softening and disturbance by foot or equipment traffic. If the footings are constructed in wet weather, we recommend that all bearing surfaces be protected with a 2 to 4-inch layer of crushed rock, quarry spalls, or recycled concrete to prevent disturbance of the footing subgrades by workers during placement of forms and reinforcing steel. We anticipate that substantial amounts of this imported angular P g material will be needed for building pads and temporary site roads. iSlabs and pavements that are placed over improperly-compacted fill soils will settle. Some measures can be taken to reduce this, such as placing reinforcing steel in slabs, and constructing pavements over a thick layer of imported gravel base. However, the best way to prevent unacceptable post-construction settlement is to properly place and compact fill soils beneath all on-grade elements. Substantial erosion control measures will be needed during this project. We anticipate that a silt fence would need to be erected along the west side of the property, and along the sides of the streams that traverse the site. Additionally, shallow, rock-lined drainage swales and sedimentation ponds will probably be necessary. Cleared areas between the proposed buildings and the wetland boundaries should be mulched with straw or a similar product during wet weather until permanent vegetation can be established. The civil engineer should develop the temporary erosion control plan. Geotech Consultants, Inc. should be allowed to review the final development plans to verify that the recommendations presented in this report are adequately addressed in the design. Such a plan review would be additional work beyond the current scope of work for this study, and it may include revisions to our recommendations to accommodate site, development, and geotechnical constraints that become more evident during the review process. Conventional Foundations The proposed structures can be supported on conventional continuous and spread footings bearing on undisturbed, medium-dense, native, silty sands or on structural fill placed above these competent, native soils. See the later sub-section entitled General Earthwork and Structural Fill for recommendations regarding the placement and compaction of structural fill beneath structures. We recommend that continuous and individual spread footings have minimum widths of 12 and 16 inches, respectively. They should be bottomed at least 12 inches below the lowest adjacent finish ground surface for frost protection. The local building codes should be reviewed to determine if different footing widths or embedment depths are required. Footing subgrades must be cleaned of loose or disturbed soil prior to pouring concrete. Depending upon site and equipment constraints, this may require removing the disturbed soil by hand. Depending on the final site grades, some overexcavation will likely be required below the footings to expose competent, native soil. Unless lean concrete is used to fill an overexcavated hole, the overexcavation must be at least as wide at the bottom as the sum of the depth of the 1 overexcavation and the footing width. For example, an overexcavation extending 2 feet below the bottom of a 3-foot-wide footing must be at least 5 feet wide at the base of the excavation. If lean concrete is used, the overexcavation need only extend 6 inches beyond the edges of the footing. GEOTECH CONSULTANTS,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 5 The followingallowable bearing pressures areappropriate for footin s constructed according 9 P9 ring to the above recommendations: Allowable Bearing_Condition Bearing Pressure Placed directly on competent, 3,000 psf native soil Supported on structural fill placed 2,000 psf above competent, native soil Where: . psf is pounds per square foot. A one-third increase in the above design bearing pressures may be used when considering short- term wind or seismic loads. For the above design criteria, it is anticipated that the total post- construction settlement of footings founded on competent, native soil, or on structural fill up to 5 feet in thickness, will be about three-quarters of an inch, with differential settlements on the order of one-half inch in a distance of 50 feet along a continuous footing. Lateral loads due to wind or seismic forces may be resisted by friction between the foundation and the bearing soil, or by passive earth pressure acting on the vertical, embedded portions of the foundation. For the latter condition, the foundation must be either poured directly against relatively level, undisturbed soil or surrounded by level, structural fill. We recommend using the following design values for the foundation's resistance to lateral loading: Parameter Design Value Coefficient of Friction 0.40 Passive Earth Pressure 300 pcf Where: 1. pcf is pounds per cubic foot. 2. Passive earth pressure is computed using the equivalent fluid density. If the round in front of a foundation is loose or slop ing,ping, the passive earth pressure given above will not be appropriate. We recommend a safety factor of at least 1.5 for the foundation's resistance to lateral loading, when using the above design values. Seismic Considerations The site is located within Seismic Zone 3, as illustrated on Figure No. 16-2 of the 1994 Uniform Building Code (UBC). In accordance with Table 16-J of the 1994 UBC, the site soil profile is best represented by Profile Type S2. The medium-dense to dense soils that underlie the site are not susceptible to seismic liquefaction. GEOTECH CO\SULTA\TS,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 6 Slabs-on-Grade The buildinc floors may be constructed slabs-on-grade y d as slabs on grade atop undisturbed, native soils that underlie the topsoil. The subgrade soil must he in a firm, non-yielding condition at the time of slab construction or underslab fill placement. Any soft areas encountered should be excavated and replaced with structural fill. All slabs-on-grade should be underlain by a capillary break or drainage layer consisting of a minimum 4-inch thickness of coarse, free-draining, structural fill with a gradation similar to that discussed later in Permanent Foundation and Retaining Walls. In areas where the passage of moisture through the slab is undesirable, a vapor barrier, such as a 6-mil plastic membrane, should be placed beneath the slab. Additionally, sand should be used in the fine-grading process to reduce damage to the vapor barrier, to provide uniform support under the slab, and to reduce shrinkage cracking by improving the concrete curing process. Permanent Foundation and Retaining Walls Retaining walls backfilled on only one side should be designed to resist the lateral earth pressures imposed by the soil they retain. The following recommended design parameters are for walls that restrain level backfill: Parameter Design Value Active Earth Pressure` 40 pcf Passive Earth Pressure 300 pcf Coefficient of Friction 0.40 Soil Unit Weight 130 pcf Where: 1. pcf is pounds per cubic foot. 2. Active and passive earth pressures are computed using the equivalent fluid densities. For a restrained wall that cannot ` deflect at least 0.002 times its height, a uniform lateral pressure equal to 10 psf times the height of the wall should be added to the above active equivalent fluid pressure. The values given above are to be used to design permanent foundation and retaining Y walls only. The passive pressure given is appropriate for the depth of level, structural fill placed in front of a retaining or foundation wall only. We recommend a safety factor of at least 1.5 for overturning and sliding, when using the above values to design the walls. GEOTECH CONSULTA\TS,t\C. SEB, Incorporated JN 97100 April 8, 1997 Page 7 The design values given above do not include the effects of any hydrostatic pressures behind the walls and assume that no surcharge slopes or loads, such as vehicles, will be placed behind the walls. If these conditions exist, those pressures should be added to the above lateral soil pressures. Also,*if sloping backfill is desired behind the walls, we will need to be given the wall dimensions and the slope of the backfill in order to provide the appropriate design earth pressures. The surcharge due to traffic loads behind a wall can typically be accounted for by adding a uniform pressure equal to 2 feet multiplied by the above active fluid density. Heavy construction equipment should not be operated behind retaining and foundation walls within a distance equal to the height of a wall, unless the walls are designed for the additional lateral pressures resulting from the equipment. The wall design criteria assume that the backfill will be well-compacted in lifts no thicker than 12 inches. The compaction of backfill near the walls should be accomplished with hand-operated equipment to prevent the walls from being overloaded by the higher soil forces that occur during compaction. Retaining Wall Backfill Backfill placed behind retaining or foundation walls should be coarse, free-draining, structural fill containing no organics. This backfill should contain no more than 5 percent silt or clay particles and have no gravel greater than 4 inches in diameter. The percentage of particles passing the No. 4 sieve should be between 25 and 70 percent. If the native sand is used as backfill, at least 12 inches of free-draining gravel should be placed against the walls. In areas of active seepage, retaining wall backfill must consist of free-draining gravel. The purpose of these backfill requirements is to ensure that the design criteria for a retaining wall are not exceeded because of a build-up of hydrostatic pressure behind the wall. The top 12 to 18 inches of the backfill should consist of a compacted, relatively impermeable soil or topsoil, or the surface should be paved. The ground surface must also slope away from backfilled walls to reduce the potential for surface water to percolate into the backfill. The sub-section entitled General Earthwork and Structural Fill contains recommendations regarding the placement and compaction of structural fill behind retaining and foundation walls. The above recommendations are not intended to waterproof the below-grade walls. If some seepage through the walls or moist conditions are not acceptable, damp-proofing or waterproofing should be provided. This could include limiting cold-joints and wall penetrations, and possibly using bentonite panels or membranes on the outside of the walls. Applying a thin coat of asphalt emulsion is not considered waterproofing, but it will help to prevent moisture, generated from water vapor or capillary action, from seeping through the concrete. Rockeries We anticipate that rockeries may be used in the site development. A rockery is not intended to function as an engineered structure to resist lateral earth pressures, as a retaining wall would do. The primary function of a rockery is to cover the exposed, excavated surface and thereby retard the erosion process. Due to the loose condition of the near-surface soils, we recommend limiting rockeries in cut or fill areas to a height of 5 feet. Proper drainage must be provided behind all rockeries, including at least a 12-inch width of quarry spalls behind the rocks. GEOTECH CO\SLTLTA\TS,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 8 ` The construction of*rockeries is to a large extent an art not entirely controllable by engineering methods and standards. It is imperative that rockeries, if used, are constructed with care and in a proper manner by an experienced contractor with proven ability in rockery construction. The rockeries should be constructed with hard, sound, durable rock in accordance with accepted local practice and City of Renton standards. Soft rock, or rock with a significant number of fractures or inclusions, should not be used, in order to limit the amount of maintenance and repair needed over time. Provisions for maintenance, such as access to the rockery, should be considered in the design. In general, we recommend that rockeries have a minimum dimension of one-third the height of the rockery. Excavations and Slopes Excavation slopes should not exceed the limits specified in local, state, and national government safety regulations. Temporary cuts to a depth of about 4 feet may be attempted vertically in unsaturated soil, if there are no indications of slope instability. Based upon Washington Administrative Code (WAC) 296, Part N, the soil type at the subject site would generally be classified as Type B. Therefore, temporary cut slopes greater than 4 feet in height cannot be excavated at an inclination steeper than 1.5:1 (Horizontal:Vertical), extending continuously between the top and the bottom of a cut. The above-recommended temporary slope inclination is based on what has been successful at other sites with similar soil conditions. Temporary cuts are those that will remain unsupported for a relatively short duration to allow for the construction of foundations, retaining walls, or utilities. Temporary cut slopes should be protected with plastic sheeting during wet weather. The cut slopes should also be backfilled or retained as soon as possible to reduce the potential for instability. Please note that loose soil can cave suddenly and without warning. Utility contractors should be made especially aware of this potential danger. All permanent cuts into native soil where groundwater seepage is not occurring should be inclined no steeper than 2.5:1 (H:V). Fill slopes comprised of compacted on-site, or similar silty, soils should not be constructed with an inclination greater than 2.5:1 (H:V). To reduce the potential for shallow sloughing, fill must be compacted to the face of these slopes. This could be accomplished by overbuilding the compacted fill and then trimming it back to its final inclination. Water should not be allowed to flow uncontrolled over the top of any temporary or permanent slope. Also, all permanently exposed slopes should be seeded with an appropriate species of vegetation to reduce erosion and improve the stability of the surficial layer of soil. Drainage Considerations We recommend the use of footing drains at the base of footings, where (1) crawl spaces or basements will be below a structure, (2) a slab is below the outside grade, or (3) the outside grade does not slope downward from a building. Drains should also be placed at the base of all backfilled, earth-retaining walls. These drains should be surrounded by at least 6 inches of 1-inch- minus, washed rock and then wrapped in non-woven, geotextile filter fabric (Mirafi 140N, Supac 4NP, or similar material). At its highest point, a perforated pipe invert should be at least as low as the bottom of the footing, and it should be sloped for drainage. Drainage should also be provided inside the footprint of a structure, where (1) a crawl space will slope or be lower than the surrounding ground surface, (2) an excavation encounters significant seepage, or (3) an GEOTECH CONSULTANTS,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 9 excavation for a building will be close to the expected high groundwater elevations. We can provide recommendations for interior drains, should they become necessary, during excavation and foundation construction. All roof and surface water drains must be kept separate from the foundation drain system. A typical drain detail is attached to this report as Plate 16. For the best long-term performance, perforated PVC pipe is recommended for all subsurface drains. Clean-outs should be provided for all subsurface and footing drains. Groundwater was observed during our field work. Seepage will likely be encountered in at least some of the excavations. This water should be drained from the site by directing it through drainage ditches, perforated pipe, or French drains, or by pumping it from sumps interconnected by shallow connector trenches at the bottom of the excavation. The excavation and site should be graded so that surface water is directed off the site and away from the tops of slopes. Water should not be allowed to stand in any area where foundations, slabs, or pavements are to be constructed. Final site grading in areas adjacent to buildings should slope away at least 2 percent, except where the area is paved. Pavement Areas All pavement sections may be supported on competent, native soil or structural fill, provided these soils can be compacted to a 95 percent density and are in a stable, non-yielding condition at the time of paving. Structural fill or fabric may be needed to stabilize soft, wet, or unstable areas. We recommend using Supac SNP, manufactured by Phillips Petroleum Company, or a non-woven fabric with equivalent strength and permeability characteristics. In most instances where unstable subgrade conditions are encountered, 12 inches of granular, structural fill will stabilize the subgrade, except for very soft areas where additional fill could be required. The subgrade should be evaluated by Geotech Consultants, Inc., after the site is stripped and cut to grade. Recommendations for the compaction of structural fill beneath pavements are given in a later sub- section entitled General Earthwork and Structural Fill. The performance of site pavements is directly related to the strength and stability of the underlying subgrade. Based on the silty, moisture-sensitive condition of the on-site soils, more crushed rock than usual should be provided beneath the asphalt to reduce the potential for softening of the underlying soils. The pavement for lightly loaded traffic and parking areas should consist of 2 inches of asphalt concrete (AC) over 6 inches of crushed rock base (CRB) or 4 inches of asphalt-treated base (ATB). We recommend providing heavily loaded areas with 3 inches of AC over 8 inches of CRIB or 6 inches of ATB. Heavily loaded areas are typically main driveways, dumpster sites, or areas with truck traffic. The pavement section recommendations and guidelines presented in this report are based on our experience in the area and on what has been successful in similar situations. Some maintenance and repair of limited areas can be expected. To provide for a design without the need for any repair would be uneconomical. GEOTECH CONSULTA\TS.INC. SEB, Incorporated JN 97100 April 8, 1997 Page 10 General Earthwork and Structural Fill All building and pavement areas should be stripped of surface vegetation, topsoil, organic soil, and other deleterious material. The stripped or removed materials should not be mixed with any materials to be used as structural fill, but they could be used in non-structural areas, such as landscape beds. Structural fill is defined as any fill placed under a building, behind permanent retaining or foundation walls, or in other areas where the underlying soil needs to support loads. All structural fill should be placed in horizontal lifts with a moisture content at, or near, the optimum moisture content. The optimum moisture content is that moisture content that results in the greatest compacted dry density. The moisture content of fill is very important and must be closely controlled during the filling and compaction process. The allowable thickness of the fill lift will depend on the material type selected, the compaction equipment used, and the number of passes made to compact the lift. The loose lift thickness should not exceed 12 inches. We recommend testing the fill as it is placed. If the fill is not compacted to specifications, it can be recompacted before another lift is placed. This eliminates the need to remove the fill to achieve the required compaction. The following table presents recommended relative compactions for structural fill: Minimum Location of Fill Placement Relative Compaction Beneath footings, slabs, 95% or walkways Behind retaining walls 90% Beneath pavements 95% for upper 12 inches of subgrade, 90% below that level Where: Minimum Relative Compaction is the ratio, expressed in percentages, of the compacted dry density to the maximum dry density, as determined in accordance with ASTM Test Designation D 1557-78 (Modified Proctor). Ideally, structural fill that will be placed in wet weather should consist of a coarse, granular soil with a silt or clay content of no more than 5 percent. The percentage of particles passing the No. 200 sieve should be measured from that portion of soil passing the three-quarter-inch sieve. GEOTECH CO\SULTkN"TS,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 11 LIMITATIONS The analyses, conclusions, and recommendations contained in this report are based on site conditions as they existed at the time of our exploration and assume that the soil encountered in the test pits is representative of subsurface conditions on the site. If the subsurface conditions encountered during construction are significantly different from those observed in our explorations, we should be advised at once so that we can review these conditions and reconsider our recommendations where necessary. Unanticipated soil conditions are commonly encountered on construction sites and cannot be fully anticipated by merely taking soil samples in test pits. Subsurface conditions can also vary between exploration locations. Such unexpected conditions frequently require making additional expenditures to attain a properly constructed project. It is recommended that the owner consider providing a contingency fund to accommodate such potential extra costs and risks. This is a standard recommendation for all projects. This report has been prepared for the exclusive use of SEB Incorporated and its representatives for specific application to this project and site. Our recommendations and conclusions are based on observed site materials, and selective laboratory testing 'and engineering analyses. Our conclusions and recommendations are professional opinions derived in accordance with current standards of practice within the scope of our services and within budget and time constraints. No warranty is expressed or implied. The scope of our services does not include services related to construction safety precautions, and our recommendations are not intended to direct the contractor's methods, techniques, sequences, or procedures, except as specifically described in our report for consideration in design. We recommend including this report, in its entirety, in the project contract documents so the contractor may be aware of our findings. ADDITIONAL SERVICES In addition to reviewing the final plans, Geotech Consultants, Inc. should be retained to provide geotechnical consultation, testing, and observation services during construction. This is to confirm that subsurface conditions are consistent with those indicated by our exploration, to evaluate whether earthwork and foundation construction activities comply with the general intent of the recommendations presented in this report, and to provide suggestions for design changes in the event subsurface conditions differ from those anticipated prior to the start of construction. However, our work would not include the supervision or direction of the actual work of the contractor and its employees or agents. Also, job and site safety, and dimensional measurements, will be the responsibility of the contractor. The scope of our work did not include an environmental assessment, but we can provide this service, if requested. r GEOTECH CONSULTAYB,INC. SEB, Incorporated JN 97100 April 8, 1997 Page 12 The following plates are attached to complete this report: Plate 1 Vicinity Map Plate 2 Site Exploration Plan Plates 3 - 12 Test Pit Logs Plate 13 - 14 Grain Size Analysis Plate 15 Footing Drain Detail Plate 16 Subsurface Drain Detail We appreciate the opportunity to be of service on this project. If you have any questions, or if we may be of further service, please do not hesitate to contact us. Respectfully submitted, GEOTECH CONSULTANTS, INC. It .47 .�,;•tJr 'G13T�Q,T��ti��v :'GNAL S'y `1� 7 EXPIRES 10 25%97 Marc R. McGinnis, P.E. Associate Jeff Johnson Geotechnical Engineer JMJ/MRM:mmm GEOTECH CONSULTANTS,IXC. s. '.,3RB -ST—�,S+48RD 5t•�1�` = i1 r :S`_•'� SE t,C , W I .c'!r I ! i� ll. 'a ST • ,131 _ - Bpl I LLJ _� / s�i'a SE 183a,,3 C v 32 SE S• ST SE 1;4T-1 ST .� H ST I S-' Td cTI c _ ..t'>'S T a ,3J ••= - CT s S !LOTH $T < SE c' St us-!Loa s J. -- - li0TN8 �- - SC M-n St 2 tD ST __ 92NG ST _ ...5.•.-rSSTH- _ T = SE 192ND`' ' ST to � ;) _1 \•� = � 1TH ST co 195TH if' SE I9 TH ST $ 198iH ST SE )9TH STSE v.r T S -;•^ - s f� CY•TN T < I .,I S. 200TH e $T� - T- SE Si 200TH ST - oe . iT $c i 202ND ST ,<' ❑ SE ST FE a a ...� S• < SI _^ h?Ci<. z _ 2G3RD Fl20]Rj < . c Mo c` of o \ H 57 „ SE 203RD <� 1 �•�� .+ SE _ 20S i > _ 1 a S iN'.- a S° — S 2GSiH- D `' `.n v = trill <!•-__ _ ,� v 57 S ' 208 s SE �24/Ti ST- SE:;7*. _ CENTER : s r M 09TH :1 ii _.1.. I }�;.K i STc�^ �S _209i ST _ SE ���1� 208TH `�i ,ST L---'-� a . s st= .s sE E > zoLT., 5 2107H ST c < < ? r o " = < SSEE 2 OTN� tit- ^^Pt$ fl cE 2IIiH Si \� � SE 210'N^ plc Sc ZI TH ,l� 212TH STD S -\' q,1�'� SE_ 0 212TH $T \i E to, SC 2UTH y.,. 'fi,. c s- .a`�•A _ i- 212TH $T SE 212Td PL 1• S tl]:M r' '0S• S ? 7.rc a t t"•Ai: s� _ 1 T� i Pt. T.,: Y';t i:r••j-_ _ <. S;w •, �- - N Q =rm��,:a J < SC 2WT- ST 16T'rl KEN �. :� < < o i5 a a VEEN- 5 _.. S= 2'STH ST L - SE TREE v.r: i C� \ Y. x _ 10300. _ SE 217'. = •ET.c-a `ST SE w e r -21! N 'N IlA^..`= £21 s- 21. STcl c, Y 5 c'_ / _ •C d' �_t•`•C,cz _ .. •t i ' - �. - S£ ` �a s- -n,;_+'�.}-• ._ ,... CP.E£ N t SE 2'S' F srr Sf IgTH Ft SE 213TH ? Ni < SE 220TH `, <c 21�T� T - PL ciF i•5t c� c .IGJO•J \y:•�l. ` `_ 220TH v r.+..•„r t 1 ..,, .- ST . . 1 I =C0= : `.-% 22/ 2 --- 222)ID _ se=� 2ui -- --- PL f ST cI --- -- v S� 22'TH �i: j LLJ y . SE 225TH Pl x SE 225 H S221, VICINITY MAP CiEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS 1 RENTON, WA Aye ` �..,o.�y�a, g ✓06 No.r Dole, Loopb Br+ F/o/i 97100 MAR 1997 1 �o 1/ l +- I I ! \ I t TP-1 3 t ► i 1 TP-�\5 �� \ t TP 16 \ 1 1 -1/*2 �TO 19 .T �- 7 1 � I TPJ10 ''` n \\ \T -81(� i�®/ Q// T'R-% O 1 \ #13-205i -i \ O WETLAND BOUNDARY 5 , �\ \ �\ QkTP14 \ \�\ 1 TP N2 \� \ 1 TP-3 WETLAND BOUNDARY 1 1 LEGEND: S 55th STREET ® EXISTING CULVERTS O APPROXIMATE TEST PIT LOCATIONS A- SiTE EXPLORATION PLAN GEOTECH CONSULTANTS TALBOT ROAD S AT S 55th STREET '� RENTON, WA .l.c ry Job No.+ oate. Role+ 97100 MAR 1997 2 TEST PIT 1 USCS Description 0 Dark brown, silty SAND with roots, fine-grained, very moist, loose (Topsoil) --- --- -Z Orangish/brown, slightly gravelly, silty SAND, fine-grained,------------ very moist to wet,loose 5 -becomes mottled and medium-dense,very moist sht 1. -becomes less mottled and very dense 10 Test pit terminated at 11 feet below grade on 3-18-97. 15 Slight groundwater seepage encountered at 3 feet during excavation. Slight caving above 4 feet. TEST PIT 2 0 q G° USCS Description 0 Dark brown silty SAND with organics, fine-grained, moist loose (Topsoil Orangish brown, mottled with gray, slightly gravelly, silty SAND, fine- grained, very moist to wet, loose sM F -becomes medium-dense 5 I Light gray, silty SAND with occasional gravel, fine-grained, very moist 'S.. to wet, dense -becomes very dense M.: 10 Test pit terminated at 9.5 feet below grade on 3-18-97. 15 Slight groundwater seepage encountered at 3 feet during excavation. Moderate groundwater seepage encountered at 6.5 feet during excavation. Slight caving below 4 feet. TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA Job No: Date: Logged by:' Plate: 97100 MAR 1997 JMJ 3 TEST PIT 3 'ev USCS Description 0 Topsoil - Orange/brown, mottled with gray, fine-grained,very moist, loose lr -becomes medium-dense,wet 5 19.6/a : SM' -becomes less mottled -becomes dense 10 Test pit terminated at 9 feet below grade on 3-18-97. Slight groundwater seepage encountered at 4 feet during excavation. Slight caving above 4 feet. 15 TEST PIT 4 Q,Q °may` 4 G0 USCS Description 0 Topsoil Orangish brown, silty SAND,fine-grained,very moist to wet,loose -becomes medium-dense sM 5 k 1 i -becomes dense 10 t Test pit terminated at 7.5 feet below grade on 3-18-97. Slight groundwater seepage encountered at 2 feet during excavation. f Slight caving below 2.5 feet. 15 ' TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA Job No: Date: [Logged by: Piste: 97100 MAR 1997 JMJ 4 TEST PIT 5 USCS Description 0 Topsoil 14.9% Orange brown, mottled with gray, silty SAND with some gravel, fine-grained, very moist to wet, loose 5 sit -becomes medium-dense -becomes dense 10 Test pit terminated at 7.5 feet below grade on 3-18-97. Slight to moderate groundwater seepage encountered at 3 feet during excavation. Slight caving above 3 feet. 15 i TEST PIT 6 o 0 G° USCS Description Topsoil sM Orange/brown, silty SAND with organics, fine-grained, very moist to wet, loose 16.2% � '�� ML Orange/brown, mottled with gray, sandy , low plasticity, very moist 7rFr to w e i im- n e 5 Orangish brown, silty SAND with some gravel, fine-grained, very sNt : moist, medium-dense 10 Test pit terminated at 7.5 feet below grade on 3-18-97. Slight groundwater seepage encountered at 3 feet during excavation. Slight caving below 6 feet. 15 TEST PIT LOGS _ GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA Job No: Date: Logged by: jPlate.,597100 MAR 1997 JMJ TEST PIT 7 USCS Description 0 Topsoil Orange/brown, silty SAND with organics, fine-grained, very moist to wet, Z : sM loose 18.2% Orangelbrown, mottled with gray, silty SAND with some gravel, 5 fine-grained, very moist to wet, medium-dense sM -becomes dense 10 Test pit terminated at 7.5 feet below grade on 3-18-97. Slight to moderate groundwater seepage encountered at 2.5 feet during excavation. Slight caving below 4 feet. 15 TEST PIT 8 4 USCS Description 0 To soil sM Reddish brown, mottled with gray, silty SAND with some gravel, fine-grained. ve moist to wet loose Orange/brown, mottled with gray, silty SAND with some gravel, .. fine-grained, very moist to wet, loose 5 sM -becomes medium-dense -becomes dense 10 Test pit terminated at 7.5 feet below grade on 3-18-97. Slight to moderate groundwater seepage encountered at 2 feetduring excavation. Moderate caving below 4 feet. 15 TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA 4 Job No: Date: Logged by: Plate: j [ I 971 DO MAR 1997 JMJ 6 TEST PIT 9 G° USCS Description 0 T1 o sot sM :I Light brown, silty SAND with organics, fine-grained,very moist to wet, loose Orange/brown, mottled gray, silty SAND with gravel and some silty 's �' seams, fine-grained, very moist to wet, loose -becomes medium-dense -becomes dense 10 Test pit terminated at 7 feet below grade on 3-18-97. Slight groundwater seepage encountered at 2 feet during excavation. Slight caving below2 feet. 15 TEST PIT 10 q G0 USCS Description 0 Topsoil Z : sm : Orange/brown, silty SAND with organics, fine-grained,very moist to wet, loose Orange/brown, mottled with gray,siltySAND with some gravel, fine- s : sM': grained, very moist to wet,loose -becomes medium-dense -becomes dense TIN ` 10 Test pit terminated at 7 feet below grade on 3-18-97. Slight groundwater seepage encountered at 2 feet during excavation. No caving. 15 ' TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA Job No: Date: Logged by: Plate: 97100 MAR 1997 JMJ 7 TEST PIT 11 G° USCS Description 0 �r To soil Orange/brown, silty SAND, mottled with gray, some gravel, fine-grained,very moist to wet, loose 17.No -becomes medium-dense 5 -becomes more sandy, less mottled, dense Test it terminated at 6.5 feet below grade on 3-19-97. 10 Slight groundwater seepage encountered at 1 foot during excavation. No caving. 15 TEST PIT 12 0 0 q G° USCS Description = Topsoil _._.. . Orange/brown, silty SAND with some gravel, fine-grained,very,moist_.. to wet,loose stet -becomes dense 5 -becomes very dense Test pit terminated at 5.5 feet below grade on 3-19-97. Slight groundwater seepage encountered at 1 foot during excavation. 10 No caving. 15 ' TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA Job No: Date: Logged by: Plate: 97100 MAR 1997 JMJ 8 BIZ. TEST PIT 13 r .may moo`' G° USCS Description 0 Topsoil sM ' Light brown, silty SAND with organics, fine-grained, very moist to wet loose sM Orange/brown, silty SAND, fine-grained with_some gravel, light oxidation, wet to very moist,loose 5 -becomes medium-dense -becomes hard Test it terminated at 5.5 feet below grade on 3-19-97. 10 p Moderate groundwater seepage encountered at 1.5 feet during excavation. Slight caving below 3 feet. 15 TEST PIT 14 USCS Descri Lion 0 1 Topsoil sM I Reddish/brown,silty SAND with organics, fine-grained, very moist to wet, loose Orange/brown, slightly mottled with gray, silty SAND with some gravel, 5 .SM.; fine-grained, very moist to wet,loose -becomes medium-dense becomes dense 10 Test pit terminated at 7 feet below grade on 3-19-97. e Slight groundwater seepage encountered at 2 feet during excavation. Slight caving at 2 feet. 15 ' ' TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA Job No: Date: ILoggedby: Plate: 97100 MAR 1997 JMJ 9 TEST PIT 15 USCS Description 0 Topsoil sM : Brown, silty SAND with organics, fine-grained, very moist to wet, loose 21 2 HX Orange/brown, mottled with gray, siltly SAND with gravel, fine-grained, very moist to wet, loose 5XX -becomes medium-dense XX sM -becomes dense 10 Test pit terminated at 9.5 feet below grade on 3-19-97. Moderate to heavy groundwater seepage encountered at 2 feet during excavati Slight caving below 2 feet. Moderate caving below 4 feet 15 TEST PIT 16 0 USCS Description Topsoil Orange-brown mottled with gray silty sand with some gravel, fine-grained, very moist, loose sM 5 _becomes medium-dense -becomes dense Test pit terminated at 7 feet below grade on 3-19-97. 10 Heavy groundwater seepage encountered at 1.5 feet during excavation. Moderate caving between 1.5 and 4 feet. 15 TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET 4 CONSULTANTS, INC. RENTON, WA n Date: Logged by. Plate: 0 MAR 1997 JMJ 10 TEST PIT 17 G° USCS Descri tiols 0 Darbecomes k bown siltySAND with organics, fine-grained, very moist, loose sM g g ry soil) wn silty SAND with organics, fine-grained, very moist to wet, 5 own mottled with gray,silty SAND with some gravel, fine-grained t, loose medium-dense dense 10 - Test pit terminated at 7.5 feet below grade on 3-19-97. Slight groundwater seepage encountered at 1.5 feet during excavation. Slight caving above 1.5 feet. 15 TEST PIT 18 USCS Descri tion 0 Dark brown silty SAND with organics, tine-grained, very moist,loose : SM (Topsoil) TTIBrown silty SAND with organics,fine-grained, vea moist to wet,loose Orange-brown slightly mottled with gray silty SAND with some gravel, fine- 5 sM grained,very moist to wet. -becomes medium-dense -becomes dense 10 Test pit terminated at 0 feet below grade on 3-18-97. Moderate groundwater seepage encountered at 2 feet during excavation. Moderate to heavy caving below 4 feet. 15 TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET CONSULTANTS, INC. RENTON, WA lJob—No: Date: Logged by. Plate: t 97100 1 MAR 1997 JMJ 11 TEST PIT 19 CG° ' USCS Description Dark brown silty Nvit organics, ine-graine , wet, loose � (Topsoil) Orange-brown mottled with gray silty SAND with some gravel, very moist, SMI loose 5 ::E -becomes medium-dense -becomes dense Test pit terminated at 6.5 feet below grade on 3-19-97. Moderate groundwater seepage encountered at 1.5 feet during excavation. 10 Slight to moderate caving from 1.5 to 4 feet. 15 TEST PIT 20 0 q G°O USCS Description Dark brown silty SAND with organics,very moist, loose (Topsoil) Orange-brown with mottled gray silty SAND with some gravel, very moist 5 to wet,loose sM -becomes medium-dense -becomes dense 10 Test pit terminated at 8.5 feet below grade on 3-19-97. Slight groundwater seepage encountered at 2.5 feet during excavation. Slight caving below 4 feet. 15 TEST PIT LOGS GEOTECH TALBOT ROAD S AT S 55th STREET x" CONSULTANTS, INC. RENTON, WA Job No: Date: Logged by: Plate: 97100 MAR 1997 JM YJ 12 '' C��C::QC�iCCC��'�/_ ggC=CCC ��CCC�.C_■_�. .:.. Mill ■_.�ECC�C..�m..E.__g • ■._■ ..g_ .�� Wo -.- - .- -----g�E-_-- _._�__..._C..__l.�.■�_�.�_`■■���■ ■om MEN ■■■■■___ ■■■_■■■_■_■ ■■ ___..■_■.■.m..le.... �.�■.■■ IN m ��■ �■■■�■ ■■ �■.�.■ , • ___■__■____�■�_��_■��•'-'���__■__fig ._..NEINE11 mom ow Immim____ IIIIII ■__■____�■�_�.Mill Ell IN ......_....._Mill Ell Mill :C:.�E��CCC�: �CC��C:..Gom :C�� MEN m • •• ��_� ■__■__ _�_■�._�■■_._mom MEN M 0 NEE Mill MMEEN . ..■■_m_�__■_ ��■ �._..._G._...... ...�....■__.__... CIIIIIIIIIIIIININ .C..._■.._._mom m NEW NO �._....�.�__.__...._. _..... .._._..�.. ..._■�C mini � ff... • MUM MOISTURE (C�� • IN • jj�� .. ... C:��� 1� CC�G::C� CCC:C�SC:C ■� I. C� ....�.. OCR■.�.IC. 1101 Ell�....-��.;�..... DC� �C.�.■ mill • -�-- = M6 IIIIIIIIIIIIIIIIN Ell Mill :C:C :El M ME MEN MIN MOM 101 am Mon son MINIIIIIIIN �.::�C:: �CC:C.�:■"C:IM MIN�. C.....■.........��....�.��..�....��■..�.. ...� • ..-■----■------1EN IN ----- - - MEMO-- . ' ��� Mon�:::C 1-:�CCC:C ZC:.:C Ems .. .. .. . .■ ...maiwou..�..1�......ME ...■.....��. ...... .. IN ..�. 1......�........�.....■..C� :C�.�::EEN Ell 1110011 :::C� /..............■m.. EllIM ....... . ...i■■■rWIN .■.i.■■ ■C■.■. ■.�..■.■�mom ME MEN ME MEN Ello _■�.....�..�.�....�.� mom ..I..�....��r...�� CC�.�■IM.'All A rCI�.........r ....�.....� ME ® '. SOIL CLASSIFICATION Slope bockfill away from loundoJion. ` ` ` TIGHTLINE ROOF DRAIN Do not connect to fooling drain. BACKF/L L See text for VAPOR BARRIER require-en/s• SLAB WASHED ROCK 4" o A• � �` . �, miri. o : 6 min. FREE-DRAINING E NONWOVEN GOTEXT/LE SAND/GRAVEL FILTER FABRIC 4"PERFORATED HARD PVC PIPE Invert at least as low as fooling and/or crawl space. Slope to drain. Place weepholes downward. FOOTING DRAIN DETAIL ._ GEOTECH CONSULTANTS TALBOT ROAD S AT S 55th STREET RENTON, WA ✓00 NO., Oo/e: Scale 7T7757]97100 MAR 1997 N.T.S. i i 1 MINIMUM 13' 12' of SILTY, RELATIVELY IMPERMEABLE SOIL OR PAVING O O FOOO � OO O O O O O w O p jO O O p O O O O O O p p o O O 6' PERFORATED 0 O PVC PIPE O 0 0 0 O O O 00 O 12' MINIMUM EMBEDMENT O + INTO DENSE SOIL O O O O APPROXIMATELY 6' O O SUBSURFACE DRAIN GEOT'ECH TALBOT ROAD S AT S 55th STREET CONSULTANTS RENTON, WA �r�� JoD No.r Oohs P/o/t � ��' 97100 MAR 1997 16 VI I. Basin and Community Planning Areas N/A VIII. Other Permits A Hydraulics Project Application was made to the Department of Fisheries on December 1, 1997. The Department of Fisheries responded on December 24, 1997 requesting further information. Pacific Engineering Design Inc. requested clarification for three items on February 3, 1998. The Department of Fisheries responded to the clarification letter on February 9, 1998. See enclosed correspondence. i _1 v "" HYDRAULIC PROJECT --- ' APPLICATION • ,,. y�'Y i �t a� DEPARTMENT OF GAME (R•C•W• 75.20.100) DEPARTMENT OF FISHERIES 600 Capitol Way North PLEASE PRINT OR TYPE General Admin. Bldg. lympla, Washington 98504 Olympia, Washington 98504 (206) 753-5897 DO NOT WRITE IN SHADED AREA (206) 753-6650 10 LAST NAI.IE FIRST 18 CONTACT Pf10fIE(S) �s ,�Q a r;y ai3 try)r"s z� « L'J x tP43; Pacific Engineering Design, Inc. 206-431-7970 ti �© res 19 STREET OR RURAL ROUTE ��it�.�4�.L4!v��e ' ►. ..oF #}.', 130 Andover Park East, Suite 300 � �(`° �� LYj,!IWHU CITY STATE ZIP T A•H C`D ,tt { Seattle WA 98188 x ° ":� .. � � ;: 12 WATER TRIBUTARY TO °t♦ 4;Is tT e Sheet and Ditch Flow Black Riverr t� SECTION SECTION TOWNSHP RANGE(E•W) COUNTY tt TYPE OF PROJECT SW 31 23 5E King Commercial Multi'-Family s"��G �4�<"�`�*'i#:�i"`"�,'�:��.:=�"�s'��•±`i�. .�DESCRIP.TION��.OF�:WORKMETHOD 'AtJD��QUIPMEN'I' ��` f� :+"��r -�'tc,�`4.'"., Construct storm systems to include detention oi .e and vaults, bio-filtrati r ....... .............. .............. . swa. .s....a .... .. y ]....spre.a lex.s....u.,ging....b.a.c.X=h.Qe....a.rid...hAX10....1Ab.Q.r.I.................................................. ...............................................................................................................................................:............................................................................................................... ..................................................................................................................................:............................................................................................................................ ............................................................................................................................................................................................................................................................... .......................................................................................................................................................................................................................:....................................... PnoposEo STARTING DATE PROPOSED FINISHING DATE March 1 1998 November 1 1998 SEPA AGENCY/DATE OF DETERMINATION C 21 OTNERPERMITS Buildin Permit IT IS UNDERSTOOD THAT NO WORK WILL SIGNATURE DATE STARTED UNTIL A SIGNED APPROVAL IS U� f. IS RECEIVED 7 TIME- L:IMiUfi AS W:mmI 'I" 3 * ' ?� v '? �. �w �ev? �v�,,' & v ,..t f..:,•r,�{.. t •s ..y.,a. r,^s xN'� ;s.'�... {,,s: a Y�<• � r..�i. R�rJ. :.t ,.�. ..t,r.Y}:::: .s;� T` ':: t ��.-" - • `' #�t 7r r,;;ig y ..f:..r ,J.,�• y 1�`:+}�1r ''�+x+.s.�'Y' �`„ �4b�,y '&r� 1`. H<� J:.'Li(i.�ex ,�`:5.�! }��•�;SR � •'`'��J 1 5� r.R t,!. a..,�i.. i, z•s T��t '�� yr a' r''��i "% �£sie`+'3,�nrt'�,� �'.{ � •es'"p� �'ti�...} .j. •sY��.' .��.+:'.°�;`!„ Ys1iz' .,N�"� '�•h,. �.a� r4.:'�s�."R '...y �Y'ax �.h,..,-R, E; s iii�� Yr. _% � ,,7�"•^ 'st�� � S � i�1 ,mot-�` 'F� ^t ,.1' t ,�`.h.`,s". J r ' �.i Y { 41 R3 . .ts t •Cz f t jt s x : h' r. T y. :.��t Y .e ! r13SJ r , , r 6, yy� }tY�,�yhy r ,�."t• r �Y :. `t pp •cs'7 ....'I' , 1,.7 t. v,��5: sstt�' $i't.�,�„yt t ..:a. ..0 z<Y`r r. sr:.,�1 k1 i "# .a ' .K „•3,� i'ga3 IT, '`'.r ap � ti<, � r,-t `,� ,�.:`y� S. �• SY •! a ,L i:.rt �Y.. .k .. 'Yt � 7 � ..r , Yr���c¢y��•� x ,.• T •�f' ;'^ gY"•Ee�'vs ?�Y let �" a �' 'ra} jt.,xa.•«t t dt i•i�'; '�'Sy�J��y�•�• {`,J�r..+� �i9+q'.e. y� f Ak 1,101 JitiJ�� � a r rx, x 1°. t i Y r $re;!4'��'T•�s r� ,,)).3�.ax��r� sY"� t:.• � f � x r x c a,k,z:.:' ,i.x3 r•.},Y:' '}. >;s t cr J' a^� •�: •L ✓- j'3'f�t.Y 3 .�.�ty �«. �� j t W:. 47.' ��• �'k.. � F'. % 33 R'k^e % a�aft 5' { Y �• r' .t;k`• `w -t Y¢�� d� ,. ,5 ,�r ;4 �:4r .> Ja .y� -x 4 ".p , w'� 'x ''i ,„ +a�`�{ J,:�' p � '._rlr; <'s ,•z Y T, Y'x r.T, t.Y rt�° x {3 r f T w r y `� w , r e i tr s a I :«x ..h a a: «S r as I Sx:..,t4r ! Y... r 3t�. (t r t•,. yr�4'uA.f V.l.%+F#i'a3 a7: �w� � A n ♦ �, !� ` Js`t i Lei + +da :.�,�Jti` i T�,�'t_�j "L 'K �{> �, , `•a .^ +; ` 1 .:V 2 s.� �'#�g v �g' ilkj•^q. r °s` • YVr's wi t� t•rY, f?:?f YX v.�':�J L $ i lSti ? X§'J .t a w.S ::;I. i F t.t't iS :��y•" .d>>r ' S J { 1'. S. 'a r`;r a, X.M fig•.... +•�`•��� Kr:i.. 1" "r'T��i��j�,..���� ��.' �`°�•'tS x . Y.'r 4 -x- � cx ��'��' �ss�� �;, w ,�y,S ft E..'t„",M�. .•,T ,�a. y,�'+!,Yxa yF k a.;YL � t �r.�4 x•x" `ii'{�"r" rX'^� akx .f p Y'�S�^iJ�Y.J '� .) � s w '���� � '. a h„' �$��,r � a��, r x.. iH. •cz'�•,. '!� (Y�•� r"��t� 3 '-idy'C S.a�'tDr` Ln„ �x'(s�*3 �,"►�i..fir., ��.' .q� t t"'i'. .,'r?'<"��`�`�;1nt, `� ¢•�f"� *• r� Y.�; 'r¢ ;r }'��.2)<3 .r« L.. :�� �•S r a� z.�'������.�_ F.. XJf}'J.,w. ! ,r,• g ,•a. !. y,.« :;,r.. t rn,y,,! rti 'fit,.. sta J 4:.zR. .•%.z 5,..t... {•.,-t....r ari..,. ..r. r ,ry.J¢JKr}, .rY• `h. dd t '` } i)•a s1.t - " r,3 r .;y. a tv`.M X� o {.-�`, { 'U•a��K �'i�.l�„, � `t ::}�'. Yi&'��?.t. ,' t t # �� �.. � r,;iX•. Y 4 4� ! " v �•su' i:• 9 Y". • fy� f 3') ,PRi ,Lal°�i � � i t. -;3! '� ; ; • ,�. I:��`..y,,y.£s. + rr,nr. i.#' �ily�. ,i'fp.e. a' .S .Y�•.,MR�•e d.,.Su(t,.' tt.( .trj .r% �..�,• r Sti t'y z;tj' r.e wl '�;« � ;s. "i ,;�" k .,st3 �t x :+ ° i ia•c:#` �'%'�'i�'°s• � �, .#.»•.r ���� �` �+r��.- �"�•Y"� �} rty�_,. %}Y.+Ja 1jr �r1. '� ,�{� fi•.13G '�����2r x� r r,�'� �'F �!•. r..>•i5�r Y6 ,,�ar� ti` ,> +� '.��- et �Y u �' t ;��Y.. •rjgs f••a�,l }' r. . ' ri t .. art t .. ■!�y3 _ k.x T �` t r'r �� Y3 �"'�'� '�y. �, g�• '�°T �- (z, �, cm .« � , . Z�s"�. ^,•sl s �r�•'' .-�.d Na N ;s.�' RY 'ty. w '^tr� � .. R �J.(r :�ti wY`�. _ i�;�4.� +`-.r):��t.. > x�l....k.J«.�.. „#2 !$:,�.A' Y � •.C� �;;- t -.�.r>�_ u 1 #�l f � `te,,6F4 1 3 .,.Ai'�#F r'�,s •j +rely z�7`,�«••�° ..ty •11 <��.U. �. u•X. ,t,# Vj.Y��y 4!�s ),3• : ��.�..�t�`��e',��',� -�'������f, t, ,�t� ��'�y;c" �I" .;vl� x` ai:• >� � ' L.tl�'Y �'�('�r� hrr� x"h�����,� ,y y *'"�F•sy,. l.e,. ..., r :.. J. ,� < ;', r ;.•.'xa....�!. !.,> ?�.. >. .;�^ � rs-.... •� ,e�>„`4t r.�ir ����•d* �r ,s;��s;�i a ::.a bzAr RECGIV ED s L1C� u i991, PACIFIC Efi ItJEERIiYG ' State of Washington DEPARTMENT OF FISH AND WILDLIFE Mailing Address: 600 Capitol Way N•Olympia,WA 98501-1091 •(360)902-2200,TDD(360)902-2207 : -� f Main Office Location: Natural Resources Building• 1111 Washington Street SE•Olympia,WA December 21, 1111 Mr. Bill Orth Pacific Engineering Design, Inc. f5vcr,/1-„ 130 Andover Park East, Suite 300 e/ 6A��7 ----. �_/ Seattle, Washington 981f38 ✓ SUBJECT: HYDRAULICS PROJECT APPLICATION - COMMERCIAL MULTI FAMILY - UNNAMED TRIBUTARY TO SPRING BROOK CREEK TRIBUTARY TO BLACK RIVER IN THE SW 1/4 OF SECTION 31, TOWNSHIP 23 NORTH, RANGE 05 EAST IN KING COUNTY, WDFW CONTROL NO. 00-D3712-01 WRIA NO. 09.0005. Dear Mr. Orth: The Washington Department of. Fish and Wildlife (WDFW) received the above- referenced Hydraulic Project Application on December 3, 1997, but we are unable to complete processing at this time for the following reason: Incomplete Application - Additional information is required. Complete plans and specifications for the project must be submitted to facilitate evaluation of potential impacts to fish resources. Information is required which accurately depicts existing conditions and proposed conditions as they will affect .state waters within the ordinary high water mark. In addition accurate depiction of wetlands, wetland impacts, wetland mitigation proposals, stormwater discharge points, and culvert installation details, before we can proceed with the review of this proposal. If you have any questions regarding the status of your application, contact me at (425) 391-4365. We appreciate your cooperation in our efforts to protect:, perpetuate, and manage the fish and wildlife resources for the state of Washington. Sincerely, Philip Schneider Area Habitat Biologist cc: WDFW - Olympia Ted Muller, WDFW - Mill Creek o PACIFIC LNGINEERING EDE�IGN INC. o CIVIL ENGINEERING AND PLANNING CONSULTANTS February 3, 1998 Mr. Phil Schneider ' Department of Fisheries Meadow Creek Office Park Suite 231, Bldg. E ' 22516 SE 64th Place Issaquah, WA 98027-8990 SUBJECT: Design/Construction Clarification Project No. 97-18 Talbot Road SDear Phil: We are currently working on the construction documents for the Talbot Road project in Renton. I have enclosed level spreader, bio-swale and creek crossing details for your review. Please review these details and respond to the questions below. ' We are approximately 3 weeks away from having complete civil engineering drawings ready to submit for your review. To help complete our drawings in a timely manner I would like to receive clarification to critical design and construction questions as follows: 1. Construction Window - Given the review speed of the City of Renton we expect to have their approval to start construction sometime between the end of March and middle of April 1998. There are two locations on the site that require creek crossing. One for roads & utilities and one for utilities only. Do you foresee any restrictions in these areas during these spring months? 2. Storm Detention - Per the preliminary storm report I recently sent you, we propose ' using the standard City of Renton detention guidelines. These guidelines require detention for the difference between the pre-developed and post-developed 2 and 10 ' year storms. Also, the detention systems must be able to convey the 100 year developed storms. With the extensive biofiltration and sheet flow through the wetlands downstream from the development site, there does not appear to be any reason to increase detention standards. Please comment. 3. Level Spreaders - I have enclosed 2 types of level spreaders. The first type is basically ' a "V" ditch with or without a leveling board. Runoff enters the ditch and then flows evenly over the down slope. The second type is a curtain drain that routes runoff back to the surface. This runoff then flows evenly over the down slope. Do you have a preference to the type used? ' GREG A OIENER P.E. JOHN R. NEWELL P.E. RICHARO A TOMKINS P.E. 130 ANOOVER PARK EAST. SUITE 300. SEATTLE, WASHINGTON 981 EIEI FAX/431-7J7S 206/431-7;Z i Phil Schneider - 2 - February 3, 1998 Talbot Road Please review these items as respond at your earliest convenience. We would like to have the hydraulics project approval in place by February 17, 1998. Please call if you have any questions. Thank you. Sincerely, PACIFIC ENGINEERING DESIGN, INC. Bill Orth Project Manager BCO:Ikr Enclosures cc: JC Trojack - Buchan Properties, L.L.C. Kent Angier- Buchan Properties, L.L.C. ' Rob Potter- Buchan Properties, L.L.C. Paul Casey - Casey Group Architects ■r rr rr rr i■r � r r Mr rr rr +rr rr rr �r r� ■r �r r�■� PRESSURE-TREATED 2"x10" DENSELY VEGETATED FOR A 1.0' MIN. MIN. OF 100.0' AND SLOPE LESS THAN 5:1 :�: (MAX.)1 3 2 1 (MAX.) 3 2 CROSS-SECTION SPREADER MUST BE LEVEL TREATED 2'x10" MAY BE ABUTTED END TO END FOR A MAX. SPREADER .083' LENGTH OF 50.0' (1-) MIN. 1.5' MIN. REBAR SUPPORTSE 0.5' MIN. 8.0' MIN. SPACING r DETAIL OF SPREADER MAINTENANCE STANDARDS 1. ANY DAMAGE TO THE SPEADER SHALL BE IMMEDIATELY REPAIRED. 2. THE DOWNSLOPE AREA SHALL BE CHECKED FOR SIGNS OF EROSION AND TO VERIFY THAT THE SPEADER IS NOT FUNCTIONING AS A POINT DISCHARGE. ANY ERODED AREAS SHALL BE IMMEDIATELY STABILIZED, AND THE CAUSE DETERMINED AND ELIMINATED IF POSSIBLE.. IF THE EROSION IS RECURRENT AND THE DESIGN, EVEN WHEN PROPERLY INSTALLED AND MAINTAINED, IS NOT ADEQUATE TO PREVENT EROSION, A NEW METHOD OF RELEASING RUNOFF SHALL BE INSTALLED IN ACCORDANCE WITH STANDARDS OF THIS CHAPTER. ANY NEW DESIGN MUST BE APPROVED BY KING COUNTY. var STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN PIPE Figure III-2 .22 - Flow Dispersal Trench O.D. 1 MIN i ;AiN FLOW TO SECOND DISPOSAL END CAP OR PLUG TRENCH IF NECESSARY a - CLEAN OUT WYE FROM PIPE o 4" OR 6" PERF. PIPE �• LAID FLAT/LEVEL I I TYPE I CB 1 ' W/SOLID COVER (LOCKING) 5 0' tA — A — - - - --2 INFLUENT PIPE (MAX. DESIGN FLOW = 0.5 CFS TYPE 1 CB WITH PER TRENCH) �I SOLID COVER ° U I D I o CLEAN OUT WYE FROM PIPE FLOW TO OTHER BRANCHING CB'S AS NECESSARY PLAN nts PIPE NOTES: O.D. 1. THIS TRENCH SHALL BE I-0"1 11,6"420010 MPX. CONSTRUCTED SO AS TO - PREVENT POINT DISCHARGE 20% MAX: MI y � AND/OR EROSION. 2. TRENCHES MAY BE PLACED NO CLOSER THAN 50 FEET TO ONE ANOTHER. ' Q s x,z 3. TRENCH AND GRADE rawer � CLEAN (� 596 FINES) iv is rnE"T® BOARD MUST BE LEVEL; ONOWE , WASHED ROCK ALIGN TO FOLLOW o c, , L CONTOURS OF SITE. — 4" OR 6" PERF. PIPE 4. GRADE BOARD SUPPORT - � ' LAID FLAT WITH HOLES UP POST SPACING AS MIN. ° u L % (PER GRAVEL BEDDING REQUIRED BY SOIL \ , 1\ REQUIRED, IF CRUSHED CONDITIONS. FILTER ROCK BACKFILL USED ' FABRIC SECTION A-A nts III-2-44 FEBRUARY, 1992 fPgfit 71 5LE 5HEET C-L For) FLQn VIED 19.0 5 TEMPORARY SEDIMENT PON } mrE�ce�Tory aE��I — Z' b"CINVEL 15Efit<1 5f'MX[n _111=1111( 5EY01-11D \ - ME U2HED CnUbHED SOCK CHQnnEL Z11_ 0n "/4 I%L" in 51ZE) FLOW cnt ''Do WE51'LDU CHQnnEL Alin. (IJnD15TUMED nI5TIHq Rip rap s� b SLOFE) Rif) rap tt. r ZH : IV Off) FLQTTEIF� Passing B inch 90 Passing 6 Inch Passing 2 Inch SJ 80 — LEVEL SPREADER 9 EMI T1IE APPI.I CANT-S/CONTRACTO1t'S RESI'ONSIRII ITY (la) Tllli CONTRACTOR SHALL BE RE-SPONSIULE FOR PROVIDING (5) A I.1. CATCH I ,1.1. COKSTRUCT1O\ r.ASEMENTS NEC1asmt1' iirFORE ADEQUATE SAFEGUARDS, SAFETY DEVICES, PROTECTIVE TUSIUERS d )r1'-S1TT WORK WITHIN TnE ROAD P-IGIITS-0E-l%,tl'. L•'QUII'MLN'T; FLAGGERS, AND ANY OTHER NEEDED ACTIONS TO. "OUTFALl. Pfloi'c 'r 1'Ilfi LIFE, HrAL7'II, AND SAF!"rY OF THE PUBLIC, AND KING CC)I1\ it r rl rr r r r r rr �r �r r� r■� r� rii r� ri SEE SHEET c-C,, rD5 FLnn VIEW r CB SEDIMENT PROTECTION 5 AVG. 100 YEQh FLOW DEPTH + 0.50t OF SWALE A B C S(°6)E FI 1LLV�QI J� - IT On QLL WQL15 B 01c-6) 3 `] 1 0.5 - �Zj ;z-s-10.5 HE TIabLELO�J G C Z 3 0.5 4.zs 0.5 Fon PLQHT%5 IHTEME1 01`i 6EM — III _1, it ill Il 5EYDnD OVEMLDI J CHQ11f1EL FLOW 2 t -- -- - - -- SEEDING TABLE Proportions Percent Percent I-(f 11_;111=111 — RUmI ADplieallon by weight P rit C;Crmimli0n oUERFLDW CHWHEL Kentucky bluegrass C.?M Prat n i Ise: as 00 (Ut1DI5FTUn5I!D nlbTlMr Dirk ,mpi •li or Svdsporl Tall fescue (FestuCa i,rundinr;ea) 40% 05 00 Ari Jlnvzir,or 0 hrl Perennial rye li Im P r nn 30% 05 00 (Derb or P nn nt Chewings fcsquc cinn r 15°G 05 00 BIO-FILTER SWALE 8 LEN (7) IT SMALL IIr Tllr APPLICANT'S/CONTRACTOR'S RFS1'ONSIn1IITY .KINLAT. NOTES TO OnTAIN ALL CONSTRUCTION FASEMFNTti NFCFSSAILY ni FORr (t ) ALL CONSTRUCTTON 4ICAi.1. nT IN ACCORDANCE WITHT11F X1Ni; INITIATING OFF-SITF. WORK WITHIN THE 1tOAD RICIITS-01'-h.tl'. .... �., r-� 1.r. 1 ....n.nnq f—" N I'll "I r..r L-4— .... ............ ...........................................•... .......... ................... .......... ........... . ............ ........... ....................... ................... .......... ....... -4............ ...... .......... ......... .......... . ........... ........ ....... ........... .... ............................ .... ................. ....... ......... ................... .. ................. .................. .......... ......... .................... ....................... ..................... ............ 1A S U; 5 .......... ........... ............ ...... ......................... .......... .......................... .......r.......... .......... .......... ........... ............ .......... --------- U U- ....................... 6 I ............... ........... ........... .......... ..........- ................... .................... ........... ...... ............................. ........... ............................................ ................ ..C3 I tfu .......... ,/_._'rr•___....__._ ...._.._.;. -4 ................. .............. .................... co am - If i t........... .................... ....................... ........... ............... 0 .......... z ...... .................... ---------- r ............ ........... .......... 4 S ....................r........... ......... 0 C, ......... .......... 0 .............. ......... ........... ........... ................ ........... -4-L .......... ........... .......... 4�........... .......... . .......... .......... .......... .............. ............ V'O )U[UL71 ............ ............ ............ ...... --.7A1- V1 ...................... ......... ....... .......... .............. ... .......... ............ ................ .......... .........I .......... 6TA re REC VED + N PACIFIC E!1GINEERI`1G State of Washington DEPARTMENT OF FISH AND WILDLIFE t Mailing Address: 600 Capitol Way N•Olympia,WA 98501-1091 •(360)902-2200,TDD(360)902-2207 Main Office Location: Natural Resources Building• 1111 Washington Street SE•Olympia,WA February 9, 1998 -; X. Mr . Still Orth Pacific Engineering Designs Inc . 130 Andover Park East, Ste . 300 - i Seattle, Washington 98188 SUBJECT: Hydraulics Project Application - Commercial Multi Family - Unnamed Tributary to Spring Brook Creek Tributary to the Black River, in the SW 1/4 of Section 31, Township 23 North, Range 05 East in King County, WDFW Control No . 00-D3712-02, WRIA No. 09 . 0005. ' Dear Mr . Orth : Below are my comments regarding the questions you asked me regarding this project : 1 . Construction Window - Work in and around the streams should ' be done after June 1 to take advantage of the drier weather so as to minimize sedimentation to the stream and the wetland . Prior to June 1 the area around the stream should well protected from erosion from disturbed areas . 2 . Storm Detention - As far as I can tell the discharge rate and water quality will have to meet the requirements of the Department of Ecology' s Stormwater Manual for the Puget Sound Basin . I would suggest that you refer to the Stormwater Technical Manual, Chapter 3-5, Page 6 on Pretreated Wetland Stormwater for the requirements . We have concerns with protecting water quality in the wetland and the tributary to Springbrook in which the wetland discharges into . This ' stream does support both coho salmon and cutthroat trout . 3 . Level Spreaders - I do not have much experience with level spreaders . I have seen them used, but I really have not followed up on how effective they are . The concern I would have is through lack of maintenance that dischare water may concentrate on this. slope and start to cause erosion . If ' the level spreaders are used I would choose the one that can .function with the minimum amount of m':aint:enarice . I thin}; t:h��t - maintenance is key and it is my opinion that over the years ' maintenance is often overlooked . I hope this information has been helpful and if you have any questions call me at ( 425 ) 391-4365 . Sincerely, Philip 'Schneider Area Habitat Biologist IX. Erosion - Sedimentation Control Design ' The erosion control calculations and soils map are included in this section. The calculations include two sedimentation ponds and one sedimentation trap. t PACIFIC ENQINEERINQ LESION INC. JOB ' fZ. CIVIL ENGINEERING AND PLANNING CONSULTANTS SHEET NO. OF r CALCULATED BY DATE l ..... .. `........:........................:......... ... ...... .. ..... ..... ..... .... .... .. ...... ... ... .. ..... ....:.... ....i.. t �.rY.�1;Mrw+�T € t �7 .�SJ... 1. .an. ..., .. ... .... .<.... .._. .......... 7 y•�� //��:. i ...`..............�...:......'..w! ..... ..... ..... ..... ...... ..... ....... ..... ..... ..... ...... ...... ...... ..... ...... .... .. _.. ..........._......_....._..................•........s.........-{......._.._................_........................._......... s u ♦ ........e.... ` ....e... _ - Intl Ar = 3.7Z A 2 R �r V. f=�r/►✓ I.Or'!. (" l' 2. ... ..=........_1.-�7....�Fs...:.. :...__........_........._:.......__....... (......:. y ................. ....... .............. 5.........: �i._.. ........._.__.......................:.............:....................... L� M'il:.A� .. k ;GL_ AID, OC�.9 o►'Z ...... QG...... .. ....: _.G.,.'S -.a.s ...... . ..-A _ ._. .... .. .........Z1'7..1.. __..S.1 ...... ,.. ... ... ............. ...................................................,.... ....... ..... ...... ...................................... ... ........ ...i.. ...:... ............: -.. 54�.�+�.. . .... .15 ...... 1 c ..�� ... _..('2 x v d .. L...LGs.................... .............._........_............ w :...._......:._._...__:......--_.:...........:......... ...... ...... ...... ... ..... ... ...... :.... ....... ...s.... t=� (Onr7 I.Z.1S � ....... ............ . ..........._........ .:2........................... # - z. ss r .. . ............................. ...$...... ..................,. �,.4..1.,.. ..... Q......`I -....... Y..... 4...., w............._--------.........._.._._.... _. ...... .... ...:.... ....: L - �. IL 0 ... .... ..............................-._i._........:.._.._._.......... _. ..... _.. ..... _ .............. ... . .. " .. .. _..... ..................._ ..__._. ..... _ ...... _ ...... ...... ........... ..... ..... ..... ..... ..... ..._ ...--- ..... _ .._. _. �. ......... ....:.... ...:... ..... 1 ....._°..:...._._._..._.__. ..:.....` .............................. l.n... ............r...r ..L.C...................a............. ..... ..........N..................._....._.._..._...............__.._............. F.................... ih... 5 Z "3 2 : 'A 2 . . . , lA S . ........ ..... ..... ............:... o r G, k 3�GGT 6.. Z-Z k - �.. 71 z 3. ` i... G:.. _ .�... .. . .... —�-- �° �o s _.......... to..:.G.... 3 0.G �.ZA 3z,.-..' ....._ h Gov_,3 __.............._.......__............._....... _..:........_............. ... _ __ .... ........................_.................. _ ...... ...... ..... ..... ..... ..... ..........:.... ...._............._.................... .... ..... ----- ....:.... ....:.... � _ Q� Z:d X G.C, . r7►Z r j.,...r... 11 ..._ '�- l : . _ _................_..._..._... _ ._..- ....._ ..... .... ..... ..... ..... ...... ...... ...._ .__ . ..... _..... --- _....... .......... ...... ...... .... ......... ....................... 130 ANDOVER PARK EAST, SUITE 300 SEATTLE, WASHINGTON 98188 (206) 431-7970 FAX:431-7975 PACIFIC ENQINEERINQ DESIGN INC. JOB " CIVIL ENGINEERING AND PLANNING CONSULTANTS SHEET NO. OF CALCULATED BY DATE . ....... 13 ........ .......G�z r2. . f�on ....._._ ...4. .....r.. _ _ .....................................,..._....._ ..... ... ........ _ ............:............_........ . I,� ........................_.._.......Y.....................................................:............. .. ... ........ _ ...... .. .. ......................... GD(79.� cat 20�0 �C ..I ............_.................._................ .. ......... a... ..., . .... .... ......... .........T......... -........ ... ... '... .. ... ... _ .... .. ... ............_._.....__.....__._......._.......5._'_ .. ...... _..............................................__.. . '_.......... ......., _h � ���.... ..... �- .......► ar�.. 2 nr v 4.,..�.. .........C.�,� .............:............:............. .... ..... ...... .. i - x ..... .................:..............._.........__i. ..._ ......._. .c�,�llm�I.� . � )� �, z _c. �l �...s....._: ... M......_ o .�... .._._.. ........... ......_...a._..................s.._..._.............. . _.. ...... ..... ...... ...... ...... . .... r ... ....«... ....„... ....i............i.... �- 1 -M»► � ............ ,. 7...� � �.�_�i�- S.fi. . r . n � ^_ti .1....�._f ............. '...._.._.._..__..._.._..... ..... ..... - Z4 ! 3 .. ... ....... ....... . t..,.. .-- _.__.......__ __ ...___...r ..... ...... ...... . ... .... ..... ._. .... : : .... ......:.... ............:..... ....:.... ►, .........................:1 . ...: . . ......... ....:.... ....: ,� k~ G ......................_........................... ................................ ........ ......_.....3..........oT .. .. I i � _ ............r e.............j..._..._....i..............i.............<...........................:.........,__r...........fi ............i.......... .....a................ ..... ............ 4 ......�. 5.. _.... 4......... .......... . ................. sr _. ..:.................... q 1B 0,6G4 . _ _ . ..__. $ ,_ _....._;............ .... ............. ........... . GF'G3 . ...... ...... .__. ...... ..... _....._........................ ......... . ...... ......... ........ ........_ �,4 _k.......... q .. ! �. . ..Grt:rr��r�' _ :.. .._.._._...................:............r . .... ._.......................: .................... ...... ...... ..... ..... .... .. ....... ...... ............................ ...... ..... .... _.__ ...._ ..... ..... ..... ..._..........._ ......__......... ..... ...... ._.. ..... ...... _...... ..... ...... ...... ..... ..... ..... ._.. ...... ..... ..................._ ........._..... __.. .... ..... ...... ...... __ _._... .__.......__._ ......__......... _._._....__ ...... ...... ...... ...... _.._ _.. - u.... . _.._......._._.......__. ...... ...... ...... ... ...... ............. ...._... ._.... ......... .. _ ..... .... i 2 130 ANDOVER PARK EAST, SUITE 300 SEATTLE, WASHINGTON 98188 (206) 431-7970 FAX:431-7975 PACIFIC ENQINEERINQ DESIGN INC. JOB " CIVIL ENGINEERING AND PLANNING CONSULTANTS SHEET NO. OF CALCULATED BY DATE �3 s�. ...........C. - s 9 -r►� IP. ............. .. ..... ........._.:................................. ........ ...... ... .+r !rr'44. = r'S ram" r7 _................_..:..............:.......... .... .. .. ...:.... .......... .... . F_........ .................. .... ..... .._.. . ...... . 146.:. s�. ��- .......... --- .......................... .. ...... ..... ._ .....5 ......... .y... ... y.i......... v /.:....� .f..............._:...................:.... .... ..._.................. ....... ... ..... .. ...... ..... ..... ........... :............. . ...... ..... ..... ......... 1-! G,Z .. ... .... ... . ... :......._.................__.............._._` ..... .._ ..... .... ..... .... ..__._._.......... ........_... ........ ..... ...... ..... ..... .. ......................... .... ..... ...... ..... ..... ... _ .... i ._............»._......r....._.... ...................... .... ..... _._......_.. C ._.._ ..... ..... ...... ...... ...... ...... _....... ...... ........ t __.._ ...»........._....................E......_........................... l......... ..... ...... ..... ...... ...... ......... t ..............................._..._......................_ _ ...... ..... _... .... ...... ...... ...... ............ ........ ........ __._.._.€......................... ..... ..... .... ...... .... .... ... ... ..... .... .. ...... .... ...... .. _........................ .... _..:...._..... ........._.....................;............d. «........._:,........._................. ..... ..._. ..... ...... ..... _.... ..... ..... ...... ...... ...... ...... ..... ....... ..... ...... ...- -- ...... ..... _. ..... .......................... ...........1. .._ _ _...... ...... ...... ...... ..... ......... ... _...... ........ s.... ...a.... L ........... '..................._ .._.. ...... ...... ...... ..........1.......... ..... ..... _... ..... ...... .._.. ...... ...... ._ ..... _.. .... ...... ...... ..... e + _....... ........ -- — — — — ....i.... ....i.... i [ .._..... ........ ...>.... .... 130 ANDOVER PARK EAST, SUITE 300 SEATTLE, WASHINGTON 98188 (206) 431-7970 FAX:431-7975 i KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL o Design of emergency overflow spillways require the analysis of a broad-crested trapezoidal weir. ' The following weir section is required for the emergency overflow spillway: FIGURE4.4.4A WEIR SECTION FOR i:MERGENCY OVERFLOW SPILLWAY �MER4ENG�l oJSreFt-oW �_ ---- --- WATER SyR.F-w- 9 / 0•3' rYlist. b pain I�0 �t 1 f i (0.-1 Win.) o The emergency overflow spillway weir section shall be designed to pass the 100-year, 24-hour design storm event for developed conditions as follov.,S: For this weir, Q,, = C (2g)'/2(2/3LH3/2 + 8/15 Tan&H5/2) using C = 0.6 (discharge coefficient); Tan = 3 (for 3:1 slopes); = 720; The equation becomes: Q100 = 3.21 (LH3/2 + 2.4H512) To find width L, the equation is rearranged to use the computed Q,O,, (peak flow for the 100-year, 24- hour design storm) and trial values of H (0.2 feet minimum). L = (Q,./(3.21H3,2)) - (2.41-112): 6 feet minimum Access/Maintenance: Pond access tracts and roads are required when ponds do not abut public right-of- way. Road(s) shall provide access to the control structure and along side(s) of the pond as necessary for vehicular maintenance. For ponds with bottom widths of 15 feet or more, the access road shall extend to the pond bottom and an access pad provided to facilitate cleaning. For ponds less than 15 feet in width, an access road must extend along one side. o Roads and pads shall meet the following criteria: - Maximum Grade: 15% to control structure, 20% into pond. - Provide 40' minimum outside turning radius on the access road to the control structure and the turnaround to the pond bottom. - Fence gates shall be provided for access roads at straight sections of road. - Access roads shall be 15' in width on curves and 12' on straight sections. - Access pads shall be 15' in width and 25' in length. ' o Manhole and catch basin lids must be at either edge of an access road or pad and be at least three feet from a property line. o Access shall be limited by a double-posted gate if a fence is required or by bollards. Bollards shall consist of two fixed bollards on each side of the access road and two removable bollards equally located between the fixed bollards. o Access roads and pads shall be constructed by utilizing one of the following techniques: 4.4.4-2 1/90 KING COUNTY, WASFIINGTON, SURFACE WATER DESIGN I`tANUAL ' FIGURE 4.4.7J RISER INFLOIV CURVES ' Weir Flow Orifice Flow Flow — -- ------- 7 T 36 100 33 44 —t— — 30 o — — 24 U - _ 21 c 18 U - - E Cc 12 10 -= - -- — _ � - M-- X 0.1 2 g 4 .q- .0 ,� ,�h1.0 t 5 a s G 10.0 ' HEAD IN FEET (measured from crest of riser) SOURCE: USDA•SCS OvrIER = 9.739 DH72 0ORIFICE = 3.782 D2Hirz O in cis, D and H in feet 4.4.7-10 1/90 KING COUNTY , WASHINGTON , SURFACE WATER DESIGN MANUAL ' 5.4.5.1 SEDIMENT TRAP ' Code: ST Symbol: Purpose To remove sediment from runoff originating from disturbed areas of the site. Sediment traps are typically designed to only remove sediment as small as medium silt (0.02 mm). As a consequence, they usually only result in a small reduction in turbidity. Conditions of Use 1. A sediment trap shall be used where the contributing drainage area is 3 acres or less. ' Design and Installation Specifications 1. See Figure 5.4.5.11A for detail. ' 2. If permanent runoff control facilities are part of the project, they should be used for sediment retention (see the introduction to this section). ' 3. To determine the trap geometry, first calculate the design surface area (SA) of the trap, measured at the invert of the weir . Use the following equation: SA = FS(Q2/Vs), where: Q2 = Design inflow based on the peak discharge from the developed 2-year, 24-hour design storm from the contributing drainage area as computed in the hydrologic analysis. The 10-year, 24-hour design storm shall be used if the project size, expected timing and duration of construction, or downstream conditions warrant a higher level of protection. If no hydrologic analysis is required, the rational method may be used (Section 4.3.3). Vs = The settling velocity of the soil particle of interest. The 0.02 mm (medium silt) particle with an assumed density of 2.65 g/cm3 has been selected as the particle of interest and has a settling velocity (Vs) of 0.00096 ft/sec. FS = A factor of safety of 2 to account for non-ideal settling. Therefore, the equation for computing surface area becomes: SA =2 x 02/0.00096 or 2080 square feet per cfs of inflow ' NOTE: Even if permanent facilities are used, they must still have a surface area that is at least as large as that derived from the above formula. If they do not, the pond must be enlarged. 4. To aid in determining sediment depth, all traps shall have a staff gauge with a prominent mark 1 foot above the bottom of the trap. 5.4.5.1-1 11/94 ' KING COUNTY , WASHINGTON , SURFACE WATER DESIGN MANUAL FIGURE 5.4.5.1A SEDIMENT TRAP ' SURFACE AREA DETERMINED - - - AT TOP OF WEIR 4' MIN. ' 1' MIN. OVERFLOW �L y 1' MIN. FLAT BOTTOM 2"-4" ROCK RIPRAP WASHED GRAVEL GEOTEXTILE NOTE: TRAP MAY BE FORMED BY BERM OR BY DISCHARGE TO STABILIZED PARTIAL OR COMPLETE EXCAVATION CONVEYANCE. OUTLET OR ' LEVEL SPREADER CROSS-SECTION 6' MIN. - - - -I III T�i-1 I I-III-I I-I 1' MIN. DEPTH OVERFLOW SPILLWAYIII-III-III-III-I l i=1►1=1TI=1 i 1=1 i I-I I I-I III-I i 1=iTi=1 i 1=1 i 1=1Ti= NATIVE SOIL OR TI I I I I= MIN. 1' DEPTH COMPACTED BACK FILL I.i II -III- 2"-4" ROCK _; ::' ; : _ MIN. 1' DEPTH 3/4"-1.5" GEOTEXTILE -III-III-III-III-I I I-III-III III=III= WASHED GRAVEL III-III III III III-III III-III-1 TRAP OUTLET ' Maintenance Standards 1. Sediment shall be removed from the trap when it reaches 1 foot in depth. 2. Any damage io the trap embankments or slopes shall be repaired. 5.4.5.2 SEDIMENT POND Code: SP Symbol: Purpose To remove sediment from runoff originating from disturbed areas of the site. Sediment traps are typically designed to only remove sediment as small as medium silt (0.02 mm). As a consequence, they usually reduce turbidity only slightly. Conditions of Use 1. A sediment pond shall be used where the contributing drainage area is 3 acres or more. 5.4.5.2-1 11/94 KING COUNTY , WASHINGTON , SURFACE WATER DESIGN MANUAL Design and Installation Specifications 1. See Figures 5.4.5.2A, 5.4.5.28, and 5.4.5.2C for details. 2. If permanent runoff control facilities are part of the project, they should be used for sediment retention (see introduction to this section). Determining Pond Geometry 1• Obtain the discharge from the hydrologic calculations of the peak flow for the 2-year, 24- hour developed storm (0 ). The 10-year, 24-hour design storm shall be used if the project size, expected timing anw duration of construction, or downstream conditions warrant a higher level of protection. If no hydrologic analysis is required, the rational method may be used (Section 4.3.3). 2. Determine the required surface area at the top of the riser pipe with the equation: SA =2 x 02/0.00096 or 2080 square feet per cfs of inflow See Section 5.4.5.1 for more information on the derivation of the surface area calculation. t 3. The basic geometry of the pond can now be determined usingthe following owing design criteria: • Required surface area at top of riser. ' Minimum 3.5' depth from top of riser to bottom of pond. • Maximum 3:1 interior side slopes and maximum 2:1 exterior slopes. The interior slopes can be increased to a maximum of 2:1 if fencing is provided at or above the maximum water surface. • One foot of freeboard between the top of the riser and the crest of the emergency spillway. • Flat-bottomed. • Minimum one foot deep spillway. • Length to width ratio between 3:1 and 6:1. Sizing of Discharge Mechanisms Principal Spillway Determine the required diameter for the principal spillway (riser pipe). The diameter shall be the minimum necessary to pass the pre-developed 10-year, 24-hour design storm (O10). Use Figure 4.4.7J to determine this diameter ( h = one foot). Note that a permanent ' control structure may be used instead of a temporary riser. Emergency Overflow Spillway Determine the required size and design of the emergency overflow spillway for the 100-year, 24-hour developed design storm using the procedure in Section 4.4.4 ' (Emergency Overflow Spillway subsection). Dewatering Orifice Use the following steps to determine the size of the dewatering orifice: Determine the size of the dewatering orifice(s) (minimum 1" diameter) using a modified version of the discharge equation for a vertical orifice and a basic equation for the area of a circular orifice. First, determine the required area of the orifice with the following equation: A,(2h)os A° 10.6 x 3 600Tgo.s where: Ao = orifice area (square feet) _ As = pond surface area (square feet) f, h = head of water above orifice (height of riser in feet) `^' 5.4.5.2-2 11/94 ' KING COUNTY , WASHINGTON , SURFACE WATER DESIGN MANUAL ' T = dewatering time (24 hours) g = acceleration of gravity (32.2 feet/second2) ' 2. Convert the required surface area to the required diameter of the orifice: The orifice diameter (D) in inches is: D = 24 x �- 3.14 3. The vertical, perforated tubing connected to the dewatering orifice must be at least 2 inches larger in diameter than the orifice to improve flow characteristics. The size and number of performations in the tubing should be large enough so that the tubing does not ' restrict flow. The flow rate should be controlled by the orifice. Additional Design Specifications Pond Divider The pond shall be divided into two roughly equal volume cells by a permeable divider that will reduce turbulence while allowing movement of water between cells. The divider shall be at least one-half the height of the riser and a minimum of 1 foot below the top of the riser. Wire- backed, 2-3.feet high, extra strength filter fabric (Section 5.4.3.1) supported by treated 4"x4"s ' can be used as a divider. Alternatively, staked straw bales wrapped with filter fabric may be used. If the pond is more than 6 feet deep, a different mechanism must be proposed. A riprap embankment is one acceptable method of separation for deeper ponds. Other designs that satisfy the intent of this provision are allowed as long as the divider is permeable, structurally sound, and designed to prevent erosion under or around the barrier. Depth Gauge To aid in determining sediment depth, one-foot intervals shall be prominently marked on the riser. Embankment If an embankment of more than 6 feet is proposed, the pond must comply with the criteria for Berm Embankment/Slope Stabilization in Section 4.4.4. FIGURE 5.4.5.2A SEDIMENT POND PLAN VIEW KEY O&I"R INTO SLOPE TO PREVENT FLOW I ROVNO SIDES ' THE POND LENGTH SHALL BC 3 TO 6 11LIES THE UAXIUVU POND WIDTH EMERGENCY OVERFLOW JSPPIILLWAY POND LENGTH .4 `O- ' rulOx�� SILT rCNCE OR IOVNALENT DNgER RISER PIPE OISCK RGE TO STABILIZED CONVEYANCE. OUTLET OR -. ' LEVEL SPREADER NOTE: PONO MAY BE FORDED BY BERU OR BY PARTIAL OR COUPLETE EXCAVATION 4 5.4.5.2-3 11/94 KING COUNTY , WASHINGTON , SURFACE WATER DESIGN MANUAL FIGURE 5.4.5.2E SEDIMENT POND CROSS-SECTION RISER PIPE CREST OF g' MIN. WIDTH (PRINCIPAL SPILLWAY) EMERGENCY SPILLWAY OPEN AT TOP W17H TRASH RACK —III— PER FIC.. 4.4,4E .I11-III-1�— _______ ITN. PERVIOUS lua"IYUE IUAIERIALS17 CSUCH AS DEWATERINC DEVICE 1 rr =--__= 1 GRAVEL OR CLEAN SAND SHALL i (SEE RISER DETAIL) �� } _ NOT BE USED. j—_ —11 I-1 I 111-1 11—� _ DfwATERINC WIRE-BACKED SILT FENCE. ORIFICE �', �L.�L1.,.. �'1f.t` STAKED HAYBALES WRAPPED �II.11 I IILII IlL I ' WITH FILTER FABRIC. OR DISCHARGE TO STABILIZED k, 1 EOUNALENT DIVIDER CONCRETE BASE CONVEYANCE, OUTLET OR (SEE RISER DETAIL) LEVEL SPREADER FIGURE 5.4.5.2C SEDIMENT POND RISER DETAIL POLYETHYLENE CAP PROVIDE AOEOUATE STRAPPING �- PERFORATED POLYETHYLENE DRAINACE TUBING, DIAMETER CORRUGATED MIN. 2' LARDER TIM METAL RISER DEWATERINC ORIFICE. TUBINC SHALL COUPLY ' MATH ASTU F667 AND = 0 S' MN AASMO M794. WATERTIGHT DCWATERINC ORIFICE, SCHEDULE COUPLING TACK WELD 40 STEEL S1UD MIN, DIAMETER AS PER CALCIAAT10NS '�Fllllll _ L-__ __- ' 18' MIN, { ALTERNATIVELY, METAL AND WIRE MAY BE USEDO TO TO CONCRETE BASE PREVENT FLOTATION �+—2Y RISER DtA. MIN,---.-, Maintenance Standards ' 1. Sediment shall be removed from the pond when it reaches 1 foot in depth. 2. Any damage to the pond embankments or slopes shall be repaired. 5.4.5.2-4 11/94 Pu Pu fit• o.� \ SIS� ,1^ Ao � 1 R am- py 1. 1 !:bi� �= Wo eD . ;'i• •BeCI p Wo �0-M 1 U •� •"• u,.: AgD Y Track 29 ii�� 76 Ng \ I Q R s rvoir AgC L Py Is led O So To 2 W Pu n Z I = i Sk Wo M 1 Pu J o ® qqMM ,u , 25 0 IBM 9 1203 A C 29 JL APB — n PY 1 g 2 a .1. . 0 451 n Wo Ur Sk o IAgC :. e Tu •�i • j �lr AmC r no•'` ' 1�\,', 1 1 I e .% No i 0 °. � •. InC •", AgB ,'le, , a •��-�' I AgD, M AmB '. So 7 ti •i .A8 R!)IIIT _ I17 _ Pu i -- •n � n a- lWO Q1 Wo IM,194 r tl' l• il `' 'r11•'\ 1.. 3,I� \ AgC I . p i Ur YaAm(;' .. p.f J PY 1 •: v' •7 AmB 3 Ng B ._4,1 Ur •i _ 1 _<: gD '32 "' AgB. . Wo AgC' : i ` ' :lii. MA I.. AgB . gq, .. *C S:A Ng L Br RQ'• a'a .1 a Wager, Wo a� Tank. _ Ur PY OS •M` i AgC AmB• So So I '•� I AgC n 1""• 'Ma .0 i AgB :.HAVES •_ Ng q U .o •,Q •t AgC ,p 1 QI0 Tu 1 ..•. , s c :� i Pu � I i NokJ AAg i 'p AkF AgC AgB Sk "r 'i Ur •� I Orive•i 1 r e• Q . •. 0. AMB- Pk 3 Os - -- A B . .. .l .i Ng Pc p g C g P I AgB .. a •Wo rgC AgB No 1 e • � e• p� AmC Re 1 % _ Uri rt i 1 Os a A—C �: ... .. i� AgC SVo O 4 AmC- Pu 1 P •• AmB Ur •••AgC Wo• 1 �. .qgp 5eao� AgC Tu i M •i' ;f• i A B Arn, .i —' C 5 , r: C '' AMCx Ur .� Ur AmC, ��• J t ' n Agp.i' L AgC Sk No Ag61 an AMC -- / •AMC Pu r ABC .`• .. -- Wo P/ u u • / AgC Am v r AmC• •fir Os A i Br ^� No N i 12 Pk x u a o 31 4r T r,,,, SOILS MAP p Q M Bf 1 ill' O _ A �r` raffle• a �___ .• _•_ t X. Bond Ouantifv Work Sheet Retention/Detention Facility Summary Sheet and Sketch and Declaration of Covenant ' The bond quantify work sheet will be included with the final engineering report. The retention/detention facility summary sheet & sketch are included. The declaration of covenant will be included with the final engineering report.