The URL can be used to link to this page

Home My WebLink AboutSWP272728 TECHNICAL INFORMATION REPORT STAFFORD CREST 1 ' CITY OF RENTON WASHINGTON GROUP FOUR JOB 497-8008 ' GROUP FOUR,Inc. 16030 Juanita-Woodinville Way NE ' Bothell, WA 98011 FAX(206)362-3819 (206) 775-4581 • (206 362-4244 TECHNICAL INFORMATION REPORT ' STAFFORD CREST RENTON, WASHINGTON Jc 0. �, 9�g• 31784 �xp�R�s 03/)8/ 00 March 4, 1998 ' Revised 5/8/98 per Client Request/City Comments ' Prepared For: Prepared By: ' STAFFORD HOMES GROUP FOUR, Inc. Contact: Rob Purser Contact: Steve Anderson 16016-118th Place NE 16030 Juanita-Woodinville Way NE ' Bothell, WA 98011 Bothell, WA 98011 Phone: (425) 488-2222 (425) 362-4244 • (425) 775-4581 TABLE OF CONTENTS ' SECTION I - Project Overview SECTION II - Preliminary Conditions Summary SECTION III - Off-Site Analysis SECTION IV - Retention/Detention Analysis and Design SECTION V - Conveyance System Analysis and Design SECTION VI - Special Reports & Studies SECTION VII - Basin and Community Plan Areas SECTION VIII - Other Permits SECTION IX - Erosion/Sedimentation Control Design SECTION X - Bond Quantities Worksheet Retention/Detention Facility Summary Sheet & Sketch Declaration of Covenant SECTION XI - Maintenance and Operations Manual APPENDIX ' Existing Basin Map Developed Basin Map ' Stafford Crest Techmical Information Report #97-8008 r SECTION I ' Project Overview ' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Infonnation Report 997-8008 PROJECT OVERVIEW PROJECT: Stafford Crest SITE AREA: 14.54 acres SITE LOCATION: The site is located southwest of the intersection of NE 36th Street and 112th Place SE in the City of Renton, Washington. EXISTING SITE CONDITIONS: Site vegetation consists of maple, alder and cottonwood trees and low growth vegetation. DEVELOPED SITE CONDITIONS: It is proposed that the site be developed with 74 single-family residences and accompanying road and utilities. SURROUNDING LAND USE: The property is bordered on the north by NE 36th Street, on the east by 112th Place SE, and on the west and south by scattered single-family residences tand undeveloped land. SOILS: The on-site soils are mapped on Sheet 5 of the King County Area, Washington, Soil Survey as Alderwood gravelly sandy loam, which belongs to ' hydrologic soil group "C". However, this classification is not consistent with the findings of the "Preliminary Geotechnical Report" prepared by ' Terra Associates, Inc. dated July 10, 1997 (Project No. T-3685). Based on this report, the on-site soils are more representative of the Ragnar soil series, which is also mapped north of the site. The Ragnar soil group belongs to hydrologic soil group "B". However, per the attached 2-2-98 Memorandum from Ted Schepper, PE of Terra Associates, Inc., the on-site soils will be modeled as hydrologic soil group "C" for the analysis and design of storm water facilities. GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 Stafford Crest Techmical Information Report 497-8008 r PROJECT OVERVIEW ' Existing Drainage The subject property is located in the Gypsy Creek drainage basin. The site is split into two tdrainage sub-basins by a ridge which runs south to north through the approximate middle of the site. Storm water runoff from the west sub-basin is overland to the northwest, exiting the site as sheet flow across the northwest property corner. Storm water runoff from the east sub-basin is ' overland to the northeast, and is tributary to an existing road side ditch located along the east property line along the west side of 112th Place NE. Storm water runoff from the west and east sub-basins recombines roughly 1/4 mile downstream. Proposed Drainage Per Core Requirement 41 of the King County Surface Water Design Manual (KCSWDM), "All surface and storm water runoff from a proposed project that proposes to construct new, or modify existing drainage facilities must be discharged at the natural location so as not to be diverted onto, or away from, the adjacent downstream property". ' However, no well-defined drainage system currently exists immediately downstream of the west sub-basin, and discharge is currently unconcentrated. In addition, portions of the conveyance system located downstream of the east sub-basin have limited capacity, and potential for impacts to adjacent properties exists (refer to the Downstream Analysis located in Section III of this report). Therefore, to minimize potential downstream impacts, developed storm water runoff ' from the subject property will be discharged as described below. It is proposed that developed storm water runoff be conveyed northwesterly to a detention vault ' located in the northwest corner of the site. Approximately 1.35 acres of developed area will bypass the proposed vault. The bypass area includes 0.14 acres of R/W dedicated to the City of Renton for the construction of improvements to NE 36`h Street. The allowable release rate from ' the vault will be adjusted as required to account for developed flows from undetained areas. An underground conveyance system will be constructed to convey developed storm water runoff ' from the proposed detention vault westerly along 36`h Street, then northerly along the east side of Lincoln Avenue. At the point of discharge from this proposed system to the natural downstream conveyance system, flows from the west sub-basin will combine with the natural, downstream tdischarge route for the east basin. Therefore, the proposed project will result in what can be considered minor, localized diversions of storm water runoff. However, these minor diversions are proposed in an effort to address/minimize potential future drainage problems. Calculations provided in Section IV of this report demonstrate that the downstream conveyance system has adequate capacity to convey developed storm water flows from the west sub-basin, as well as diverted portions of the east sub-basin, during 100-year/24-hour developed overflow conditions. ' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report 497-8008 PROJECT OVERVIEW ' Frontage Improvements The frontage improvements required along 112`' Place NE are located within the limits of the ' City of Newcastle. The City of Newcastle uses the King County Surface Water Design Manual (KCSWDM) as a guideline for the analysis and design of drainage systems. Per Section 1.2.3, Core Requirement #3, Exemptions From On-Site Peak Rate Runoff Control located on page ' 1.2.3-5 of the KCSWDM, on-site peak rate runoff control will not be required for a proposed project if the project proposes to construct 5,000 square feet, or less, of new impervious surface. t The required frontage improvements will result in less than 5,000 square feet of new impervious surface. Therefore, detention will not be provided for the proposed 1121h Place NE frontage improvements. The frontage improvements required along NE 36`h Street are located within the City of Renton. Approximately 0.14 acres of on-site area will be dedicated as R/W for the construction of these improvements. The resulting new impervious surfaces have been analyzed as bypass. The allowable release rates from the proposed detention vault have been adjusted (reduced) to account for flows from developed bypass areas. Therefore, flows from the required NE 36°i ' Street frontage improvements have been accommodated in the design of the proposed detention vault, and no additional detention is required. r i ' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 RCV BY:GROUP FOUR, INC, ; 2- 2-98 ; 1 :43PM 2068214334-► 2063623819;# 1 FAX TERRA ASSOCIATES, Inc. ' MEMORANDUM To Consultants in Geotechnical Engineering,Geology and Environmental Earth Sciences To: Rob Purser Fay Tuna er. �88- -]\ b U29� ' Stafford Homes Date: 2-2-98 From: Ted Scbepper, PE Project Num"oer: 3685 ' Subject: Soils HydroIogie Classification Project Name: Tharp Property- Renton,WA ' Rob: As discussed in our July 11, 1997 geotechniczl report, from a geologic perspective, we believe the soil conditions at the site would be more representative of a Ragnar soil series as opposed to an Alderwood soil as mapped by the SCS in their"Soil Survey of Ting County". AIderwood soils are typically glacial till which is comprised of a weathered to unNNeaihered silty sand ,Kith gravel. The soils at the site are not till and were ' likely deposited from glacial outwash. Although from a geologic perspective the soils would not be A.lderwood, from a hydrologic perspective their permeability characteristics would be similar particularly when consider ing a typical upper weathered glacial ' till zone. As discussed in our October I S'b. 1997 supplemental report on infiltration,the outwash soils on this site are dense and contain a suffick-nt amount of fines, N,�-hich will limit their pezzr eability. Therefore we believe it would be appropriate to znal)-ze and design storm water facilities using a hydrologic group "C" ' rating. We trust the information presented is sufficient to meet your current needs. Should you have any questions ' please call. ' cc: Carmen Vanier Group Four,Inc. 362-3819 Ted Sebepper,PR 12525'( R]ows Road, Suite l(?1,Kirklalat; washing,.on 9S034 Phone No.(206)S2I-7777 Fax: 821-4334 ' Page 1 of 2 King County Building and Land Development Division TECHNICAL INFORMATION REPORT (TIR) WORKSHEET PROJECT ENGINEER MD DESCRIPrIONPART I PROJECT OWNER AND PAW 2 PROJECT LOCAMON ' ProjectOwner Stafford Homes Project Name Stafford Crest Address 16016-118th P1 . NE, Bothel 1 , WA 9E 011 Location Phone 425 Township 24N Project Engineer Carmen 0. Vanier Range 5E Company Group Four, Inc. Section 32 425-775-4581 Project Size 14.54 AC Address Phone 16030 Juanita-Wdnvle WayNE B thell 980 1 Upstream Drainage Basin Size AC Subdivision Q DOF/G HPA Q Shoreline Management Q Short Subdivision Q COE 404 Q Rockery Q Grading Q DOE Dam Safety ® Structural Vaults ' Q Commercial Q FEMA Floodp!ain Q Other Q Other Q COE Wetlands ED HPA ' PART 5 SITE COMMUNITY Community ' ) Newcastle Community Planning Area Drainage Basin ' Gypsy Creek Sub-Basin Q River Q Floodp!ain ' Q Stream Q Wetlands 0 Critical Stream Reach Q Seeps/Springs 1� Depressions/Swales Q High Groundwater Table 0 Lake Q Groundwater Recharge Steep Slopes Q Other Q Lakeside/Eresion Hazard Soil Type Slopes Erosion Potential Erosive Velocities ' Ragnar "B" 6-15% Moderate Medium 15-25% Severe Medium-Rapid ' Q Additional Sheets Attatched 1/90 Figure 1 ' King County Building and Land Development Division page2of2 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET U-1 PAWS DEVELO ' REFERENCE LIMITATION/SITE CONSTRAINT Ch.4-Downstream Analysis No well defined conveyance directly 'downstream of ' 0 west on-site suh-hasin limited ra ncjty along partions, E-1 of conveyance system located downstream of east on-site F-1 sub-basin. Construct new tight-line downstream conveyance system to convey flows to point of sub-basin O recombination. Additional Sheets Attatched MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS DURING CONSTRUCTION FOLLOWING CONSTRUCTION ® Sedimentation Facilities ® Stabilize Exposed Surface LAX Stabilized Construction Entrance E—L] Remove and Restore Temporary ESC Facilities ® Perimeter Runoff Control ® Clean and Remove All Silt and Debris EE Clearing and Grading Restrictions [E Ensure Operation of Permanent Facilities EE Cover Practices 0 Flag Limits of NGPES M Construction Sequence Other 0 Other PART 10 SURFACE WATER SYSTEM 0 Grass Lined Channel E:J Tank 0 Infiltration Method of Analysis ® Pipe System C] Vault Depression SBUH Open Channel Enercy Dissapator Flow Dispersal Compensation/Mitigation 0 Dry Pond Wetland Waiver of Eliminated Site Storage Wet Pond Stream Regional Detention N/A Brief Description of System Operation Convey storm water runoff in underground storm pipe to a detention/over-sized water quality vault located in N14 corner of site Facility Related Site Limitations Additional Sheets Attatched Reference Facility Limitation (May require special structural review)r � Drainage Easement EM Cast in Place Vault Other Access Easement ® Retaining Wall Native Growth Protection Easement Rockery>4'High ® Tract Structural on Steep Slope E:J Other PART 14 SIGNATURE OF • . • E• ' I or a civil engineer under my supervision have visited the site. Actual site conditions as observed were incorporated into this worksheet and the attatchments. To the best of my knowledge the information provided here is accurate. 3.3 1190 Figure 1 Stafford Crest Techmical Information Report #97-8008 29 28 SE BOTH I ST i SITE `rF` 32 NE 36TH S 35 89j,�,pC t O i v i i NE 33RD ST N 30TH ST NF 31ST ST I i NE 27711 ST N 2 05 W y z 0' 5 Q `� o Z BL VD J� ' Figure 2 - Site Location Map Not to Scale ' GROUP FOUR,Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report #97-8008 i SECTION II ■ Preliminary Conditions Summary 1 1 1 iGROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 DD� I-- _ �sno , cvl = _ LAKE WASHINGTON -- ---- S L 72n St. OUTFALL ------ r LIJ NE — ti.. " 9✓ P. J ) Go X X .A. \ -t ""' r �t"y—f -- V.... J ..•C- ._..1--•1—:� —`_Is I_ + •'y. v 7ath CEDAR IM APM— ,13 -I J t v 1� — 1 �_4Mc ON C ' �__ y.:. �' 80tf1 ..1 - C _ �> 74 o I LLJ Nk Oft h;/ St �� ,;, cl .Z •E i Oth S -�-1- r � _ -�: —._______ 1 1 SE 84 t z_ � �--_ tic--=--1-- D E-7 'N ,E 3M �i` i� St LL -Sir 5 � YPSY SUBB d - ATERSHED NDAclq I Ll -- SE 9 s t t LEGEND• MODEL SUBBASIN ID AREA DRAININ ENTRANGO DRAINING TO STORM DRAIN SYSTEM U " scr""S7 " mvmps "Rmmws SURFACE CONVEYANCE RT. WZHINGTON MIZOM CALIFOFU ~' ' • • — POND OR SWALE - -- SUBBASIN BOUNDARY .[ FLOW NODDEE Figure 2 FLOW N Drainage Features of 500 0 500 ,000 the Gypsy Subbasin SCALE IN FEET iStafford Crest Techmical Information Report 997-8008 , •� •f/ � ` • \ � `�� / .�' � _-/ •ram 1 01 ay r ek — • In Y ■ 1■ I • ' III-- -li p / 1 • �_--�' Figure 3(a)—Mercer Island Quadrangle Map ' Scale: 1"= 1,000' ' GROUP FOUR, Inc. 16010 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report #97-8008 LU ( - a} {o �° of o o E 0 ICD II 0 1' ° b t C31 I h o II El o 32 r" C S.E. BTI 3 . 3 0 0 150 1 300 Figure 3(b) — 1954 Aerial Topographic Survey ' Scale: 1" =400' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Infonnation Report #97-8008 May e KpCU�: . . • wL ■ B AgD . . . SEE O, No • ItSITE*ones *no as 1 9 man 1 AgC " ■' f `AgD . ' . . .. ■ � :::v � • • . . , 1. so so 1+ on . • InC A. • AkF / ■ r ' an ■ an 0Is • ■• �+: • �� r 1 Py ■ { AkF 1 x. - - -_-- - - 04 r • 1 r gC AgD m •. • BM' 30J M -lie Figure 4 - Soils Map Scale 1"= 1,000' Taken from the King County Area, Washington Soil Survey-Sheet S 1 GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 1 ' Stafford Crest Techmical Information Report #f97-8008 r SECTION III Off-Site Analysis GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 i Stafford Crest Techmical Information Report #97-8008 OFF-SITE ANALYSIS Upstream Tributary Area ' Based on inspection of Figures 3(a) and 3(b), no significant flows from upstream, off-site areas are tributary to the subject property. GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 OFF-SITE ANALYSIS Downstream Analysis ' West Sub-Basin: Storm water runoff from the on-site west sub-basin currently exits the site as sheet flow across the northwest corner of the site. Flow continues northerly as sheet flow across private, single-family residential development roughly 750-800 lineal feet prior to ' entering a large, low-lying forested area. Refer to Figure 3(b) for delineation of the on- site west sub-basin downstream travel path, and approximate location of the low-lying area. East Sub-Basin: Storm water runoff from the on-site east sub-basin currently exits the site across the east property line prior to entering a roadside ditch located along the west side of 112th Place SE. Flow from this roadside ditch is conveyed northerly along 112th Place SE to an 18 inch diameter concrete culvert located at the intersection of NE 36th Street and 112th Place SE. Flow from this culvert discharges again to the roadside ditch, which is relatively uniform in cross-section, and shows no evidence of significant scouring or erosion. This portion of the roadside ditch is vegetated with grass and weeds approximately 6 inches in height, is trapezoidal with a 1-1/2 to 2 foot wide bottom, 6 to 7 foot wide top, and is roughly 2-1/2 feet deep. Flow is conveyed northerly in this roadside ditch roughly 350 lineal feet to a gravel access road which appears to be serving the Prellwitz Short Plat. Flow is conveyed northerly under this gravel access road in roughly 25 lineal feet of 18 inch diameter ADS N-12 culvert. Flow from this culvert outfalls to the road side ditch, and continues northerly another 100 lineal feet to an 18 or 24 inch ' diameter steel pipe which conveys flow northerly roughly 25 lineal feet under the gravel driveway to the residence located at 3711. Flow is discharged on the north side of this gravel driveway,just north of the intersection of SE 86th Place and 112th Place SE. At this point, flow combines with developed flows from the plat of VAhitehawk, which discharges westerly across 112th Place SE from the east. Flow continues northerly along the west side of 112th Place SE in a series of 18 inch concrete driveway culverts (to the I residences located at 3767 and 3815) and roadside ditch. However, from this point northerly, this roadside ditch becomes less and less well-defined, and begins to meander away from the road. The roadside ditch becomes less of a constructed ditch in appearance, and more closely resembles a natural drainage course located in a broad, low- lying, heavily vegetated area. This drainage course is loosely rock-lined in areas. Visual inspection indicates that capacity prior to overtopping onto adjacent private properties may be limited in some areas. Flow is conveyed northerly roughly 400 lineal feet in this roadside ditch/natural drainage course prior to discharging to a large, low-lying, forested ' area. This area is roughly 100 feet wide by 400 feet long, and is located between 110th Avenue SE and 112th Place SE. Refer to the East Sub-Basin "Downstream Drainage GROUP FOUR,Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report 4`97-8008 Features Map" for delineation of the on-site east sub-basin downstream travel path. Refer to Figure 3(b) for the approximately location of the low-lying area. ' Combined Downstream: Storm water runoff from the west and east on-site sub-basins combine within the low- lying, forested area., which is located within 1/4 mile downstream. No obvious signs of defined conveyance were observed within this area. Flow appears to disperse throughout ' this area, prior to draining generally westerly and eventually entering a 12 inch ADS N- 12 culvert located along the east side of 110th Avenue SE (Lincoln Avenue). This 12 inch culvert conveys flow westerly across 110th Avenue SE to an underground storm system located along relatively newly constructed frontage improvements on the west side of 110th Avenue SE. Flow is conveyed northerly in this underground storm system roughly 100 to 150 lineal feet prior to discharging to a deep, grass-lined ditch located along the west side of 110th Avenue SE. Flow is conveyed northerly in this ditch to the intake of a 24 inch concrete culvert located under an earthen road/embankment. Flow is conveyed northerly in this culvert prior to discharging to vegetated drainage course and continuing downstream, eventually entering Lake Washington. Refer to the East Sub- Basin "Downstream Drainage Features Map" for delineation of the combined downstream travel path i GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 r E. A.Brickcr, ct ux }•'' I' S� t 5.00 Ac. 4.46 Ac. C.D. Patterson r, Y .N •�- v, ,�, ,r-f Ux 3 . ' NI 1.1 • N • I 8O N ri .6• Eileen Thrasher 5.00 I 3RD 7', a ; _ r W TWA S I N ,C,!T:•. -'N,• G.F. Lansinc ct Ux N � , � � •'�, 1. '' , • Ut 10, W 47 NOT OPEN o - Federal S.& L. Ins. Corp _ -----• r-- —_-----_--- �x _ d 1.67Ac. ,�1�t I 24"I i\ :�,.>+' AC W. D.Jone5 `�o`' ��`:� AG eWI D.Jones Corp -e I E,N - - Ul;v \ eat) ,,~.1 ,l+ , f .N N C �� 1.91 AC.,6 Z.10AC. Wm. Belmondo ------ �, N EASTSIDE N s _ o:a !— n457NE - �9 - - Will itchaw)c �3 o 0o Zoe S• 18 �,�y." r N Cori Olson Carl T. Olson `° I bw-Iyng area Y I'n. I 0.16 AC. �� 2 I; 1.04 Ac. 0,69Ac. y'43 W Y1437 63 7.2 vv\ a 4.41AC. Robert Nissen - •• 1`� ' '' r• -1 -Z I09•r t -- ---1��-•- I �f \� Edmund J. Neuman h - ; •.. •`_° to V ' 166 a ' I'.� ;•„ 3 :'� —. 3 4 • ti E 86T1-1 IM ^ Wei r 5 r -6 '7 7 d:\\ • 6 N �° NOT S T OPEN r n --I L' a IN.01 �? Qo 4 � A rr v 82Q•• C 1 2 - :C m„ 67.57 _ �i �S.�9 r ,� Z99 :r • 1'flb rJJ 45 l0 U :• ti.C. 8 i EO YY ' 86TH s PL. r:�u• " b�,, " „"s AN s9,1 �' tto.» SSE:. -.86TH _ �L L�-_�.l 24 W es.12 r. 144.8 9 ,: ,13 12 ��/* g H ��/ 91so ,<< .. I aslr p511 .1 ` l51 b S•,G.na. wY ua TH. .�"sa•JM. f' ,.•4.. 356S t 23 a a IQ c, �31.a1 13134 oS'Ile �fr � �, r 6 �. d SO (V E. I' 10 dl J Y �� ' r ►ao� I'•� , -7 Zoo - 60 Z96 0J ¢ 35 - I b r 10.. Yv •._n•.•... , 45 sE 88TH CT 19 18 I7 b7 too 75 '15`' IJo v 5 1 `o o Is,.01 JO ." 105?4 I I -f so �z ,•ir• Y r. arnt 7I 'c'' ` •t , •^ �• OffrCE ' it IN Y 1 ,+ .� 721 J� 11 t J,N , � e,1�t�, Y�{ •3 6 ' SITE D. y• I !•r. {� { +i t1}Y �. �n+�� J f!J�a♦'i .. Y+}1 \\ �` `a % t� 75 bs I I y T �..� ,N.r1 )(I,iS' a+..'1:.r;FiJ. Y,•,r5f°r <rf�� 1M1:i..� ' \\ —_'•—.- =� r ,} i i , t n r y Isf.l7` �• 1 I (A) I r I-j- ;, 2.5�4•i•,}1,y 15 C,1� 1 .i • ' I A N , m I I --- +�'.11'I +'i 1 ��\ )r .L,Y�{rl .�'f'.(, ''�y.}ti i, ',• 140 �y ' T �•'7^ IY ,.- A e '7itf,t,I. ; I t , •JJr 1, •. S.P. 23-76 ' 11 t ,r IIM 1 1 (tn.1 ' 1 r i by so `` N F y 7� V 4' S+• n H oL" I 1 _ IC1 dso ►r,e ar ,+• 1 1,+J r1�91. .;• OA.07 P+ NO/ 915 OPEN 400 LAKE WASH I N c -rn �� JSo Stafford Crest Techmical Information Report 497-8008 ' SECTION IV ' R/D Analysis & Design r t t t GROUP FOUR, Lac. 16030 Juanita-Woodinville Way NE ' Bothell, WA 98011 Stafford Crest Techmical Information Report 497-8008 ' R/D ANALYSIS & DESIGN Detention/Oversized Wetvault Analysis GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 ' Stafford Crest Techmical Information Report 497-8008 R/D ANALYSIS & DESIGN ' PART A: Existing Site Hydrology The subject property is located in the Gypsy Creek drainage basin. The site is tsplit into two drainage sub-basins by a ridge which runs south to north through the approximate middle of the site. Flows from the on-site sub-basins recombine ' approximately 1/4 mile downstream. Therefore, the site will be analyzed as a single threshold discharge area. Due to downstream constraints, an underground storm system will be constructed to convey developed storm water runoff from the site to an acceptable discharge point. The use of this system will result in storm water runoff being diverted away from the natural drainage systems located directly downstream of the on-site sub-basins in an effort to address/minimize potential future drainage problems. This underground storm system will be sized and designed to safely convey developed storm water runoff from the site directly to the downstream system during the 100-year/24-hour design storm. At the point of discharge of this system, storm water runoff from the on-site sub-basins has already recombined. As a result, the use of the site as a single threshold discharge area is not expected to impact the natural downstream drainage systems, and can be considered a valid design assumption. The total site area consists of 14.54 acres. Per the attached 2-2-98 Memorandum from Ted Schepper, PE of Terra Associates, Inc., the on-site soils will be modeled as hydrologic soil group "C" for the analysis and design of storm water facilities. The existing land use is wood or forest land: young second growth or brush. This ' corresponds to an existing curve number of 81. The existing time of concentration travel path is delineated on the attached Existing Basin Map. r GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE ' Bothell, WA 98011 4/10/98 GROUP FOUR, Inc . page 1 Stafford Crest ' #97-8008 R/D Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- ' BASIN SUMMARY BASIN ID: 100EX NAME : 100yr/24hr Existing SCS METHODOLOGY TOTAL AREA. . . . . . . : 14 . 54 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERVIOUS AREA ' PRECIPITATION. . . . : 3 . 90 inches AREA. . : 14 . 54 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 56 . 92 min IMPERVIOUS AREA ' ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 00 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 143 . 00 ns : 0 . 4000 p2yr: 2 . 00 s : 0 . 2450 TcReach - Sheet L: 58 . 00 ns : 0 .4000 p2yr: 2 . 00 s : 0 . 0862 TcReach - Sheet L: 99 . 00 ns : 0 . 4000 p2yr: 2 . 00 s : 0 . 0223 TcReach - Shallow L: 125 . 00 ks : 3 . 00 s : 0 . 0223 TcReach - Shallow L: 196 . 00 ks : 3 . 00 s : 0 . 1020 ' PEAK RATE : 4 . 66 cfs VOL: 2 . 38 Ac-ft TIME : 530 min BASIN ID: 10EX NAME : 10yr/24hr Existing SCS METHODOLOGY ' TOTAL AREA. . . . . . : : 14 . 54 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 14 . 54 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 ' TIME OF CONC. . . . . : 56 . 92 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 00 Acres CN. . . . . 98 . 00 ' TcReach - Sheet L: 143 . 00 ns : 0 . 4000 p2yr: 2 . 00 s : 0 . 2450 TcReach - Sheet L: 58 . 00 ns : 0 . 4000 p2yr: 2 . 00 s : 0 . 0862 TcReach - Sheet L: 99 . 00 ns : 0 . 4000 p2yr : 2 . 00 s : 0 . 0223 TcReach - Shallow L: 125 . 00 ks : 3 . 00 s : 0 . 0223 TcReach - Shallow L: 196 . 00 ks : 3 . 00 s : 0 . 1020 PEAK RATE : 2 . 53 cfs VOL: 1 .44 Ac-ft TIME : 530 min BASIN ID: 2EX NAME : 2yr/24hr Existing ' SCS METHODOLOGY TOTAL AREA. . . . . . . : 14 . 54 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 14 . 54 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . . 56 . 92 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 00 Acres t CN. . . . : 98 . 00 TcReach - Sheet L: 143 . 00 ns : 0 .4000 p2yr: 2 . 00 s : 0 . 2450 TcReach - Sheet L: 58 . 00 ns : 0 . 4000 p2yr: 2 . 00 s : 0 . 0862 TcReach - Sheet L: 99 . 00 ns : 0 . 4000 p2yr: 2 . 00 s : 0 . 0223 TcReach - Shallow L: 125 . 00 ks : 3 . 00 s : 0 . 0223 TcReach - Shallow L: 196 . 00 ks : 3 . 00 s : 0 . 1020 PEAK RATE : 0 . 96 cfs VOL: 0 . 70 Ac-ft TIME : 540 min Stafford Crest Techmical Information Report #97-8008 R/D ANALYSIS & DESIGN ' PART B: Developed Site Hydrology It is proposed that the 14.54 acre site be developed with 74 single family residences. Per Table 3.5.2B of the King County Surface Water Design Manual, the percent impervious area is calculated below. 74 DU/14.54 GA= 5.09 DU/GA=48.36% Impervious ' Therefore, the total developed impervious area consists of 7.03 acres, and the total developed pervious area (lawns/landscaping) consists of 7.51 acres. However, a portion of the developed site will bypass the proposed detention vault. The total bypass area and the area to be detained are listed below. Detained: Impervious Area= 6.82 acres CN= 98 ' Pervious Area= 6.37 acres CN = 86 Time of Concentration = 18.48 minutes ' 100' sheet flow over lawns at 1.00% 230' shallow flow in concrete gutter at 7.51% 879' channel flow in smooth-wall pipe at 4.71% avg. slope Bypass: Impervious Area= 0.21 acres CN = 98 Pervious Area= 1.14 acres CN = 86 ' Time of Concentration = 5.00 min assumed conservative minimum 1 r r r r r GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 1 4/10/98 GROUP FOUR, Inc . page 1 Stafford Crest ##97-8008 R/D Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- BASIN SUMMARY BASIN ID: 100DT NAME : 100yr/24hr Detained Area SCS METHODOLOGY TOTAL AREA. . . . . . . : 13 . 19 Acres BASEFLOWS : 0 . 00 cfs ' RAINFALL TYPE. . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 6 . 37 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 18 . 48 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 6 . 82 Acres CN. . . . : 98 . 00 PEAK RATE : 9 . 64 cfs VOL: 3 . 24 Ac-ft TIME : 510 min ' BASIN ID : 10DET NAME : 10yr/24hr Detained Area SCS METHODOLOGY ' TOTAL AREA. . . . . . . : 13 . 19 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 6 . 37 Acres TIME INTERVAL. . . . . 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 18 . 48 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 6 . 82 Acres CN. . . . : 98 . 00 PEAK RATE : 6 . 52 cfs VOL: 2 . 22 Ac-ft TIME : 510 min BASIN ID: 2DET NAME : 2yr/24hr Detained Area SCS METHODOLOGY TOTAL AREA. . . . . . . : 13 . 19 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERVIOUS AREA ' PRECIPITATION. . . . : 2 . 00 inches AREA. . : 6 . 37 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 18 . 48 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 6 . 82 Acres CN. . . . . 98 . 00 PEAK RATE: 3 . 77 cfs VOL: 1 . 33 Ac-ft TIME : 510 min r 4/10/98 GROUP FOUR, Inc . page 1 Stafford Crest #97-8008 R/D Analysis & Design BASIN SUMMARY BASIN ID: 10013Y NAME : 100yr/24hr Bypass Area ' SCS METHODOLOGY TOTAL AREA. . . . . . . : 1 . 35 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERVIOUS AREA ' PRECIPITATION. . . . : 3 . 90 inches AREA. . : 1 . 14 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 5 . 00 min IMPERVIOUS AREA ' ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 21 Acres CN. . . . : 98 . 00 PEAK RATE : 0 . 84 cfs VOL: 0 . 29 Ac-ft TIME : 500 min ' BASIN ID: 1013Y NAME : 10yr/24hr Bypass Area SCS METHODOLOGY TOTAL AREA. . . . . . . : 1 . 35 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 1 . 14 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 5 . 00 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 0 . 21 Acres CN. . . . : 98 . 00 ' PEAK RATE : 0 . 53 cfs VOL: 0 . 19 Ac-ft TIME : 500 min BASIN ID: 2BY NAME: 2yr/24hr Bypass Area SCS METHODOLOGY TOTAL AREA. . . . . . . : 1 . 35 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 1 . 14 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . . 5 . 00 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 21 Acres CN. . . . : 98 . 00 PEAK RATE : 0 . 27 cfs VOL: 0 . 10 Ac-ft TIME : 490 min i ' Stafford Crest Techmical Information Report 497-8008 ' R/D ANALYSIS & DESIGN PART C: Hydrologic Analysis Proposed stormwater detention facilities will be designed in conformance with the ' Department of Ecology Storm Water Management Manual for the Puget Sound Basin (DOE Manual), and the City of Renton. Therefore, in conforming to both Ecology and City criteria, it has been determined that the post-developed peak rate of runoff from the subject property will be limited to the 50% of the pre- developed peak runoff rate during the 2-year/24-hour design storm, while ' maintaining the existing condition peak runoff rate for the 10- and 100-year/24- hour design storms. At the request of the City of Renton, a 30% factor of safety will be applied to the required design volume, as required in the KCSWDM. The typical correction factor for single-family residential development as required by the DOE Manual is 20%. Therefore, the proposed design is in excess of the requirements outlined in the DOE Manual. ' In addition, since more than 1.0 acres of impervious surfaces subject to vehicular use is proposed, and a Type 2 stream is located within one mile of the project site, ' the site is subject to Special Requirement #5, as outlined in Section 1.3.5 of the KCSWDM. To meet the requirements of Special Requirement #5, and to eliminate the need for a biofiltration swale, an "oversized" wetvault is proposed. The design water surface area of the wetvault will be equal to or greater than 1.50 percent of the total impervious surfaces subject to vehicular use. The design volume of the wetvault will be equal to the total volume of runoff from the tributary sub-basin proposed developed conditions using a water quality design storm event having a total precipitation, Pt-wq, where Pt-wq is one-third of the 2- year/24-hour total precipitation. The resulting design volume will be increased by a factor of 50 percent as required by the City of Renton. The required computations will be performed using the Soil Conservation Service Unit Hydrograph (SCSUH) method with Type IA rainfall distribution and 24- hour design storm durations. The computer program "WaterWorks Version 3.1" will be used to develop and manipulate hydrographs, and perform the required level pool routing. GROUP FOUR,Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 Stafford Crest Techmical Information Report 997-8008 ' R/D ANALYSIS & DESIGN ' PART D: R/D System Attached are the calculations, equations, references, storage/volume tables, graphs and other information used to determine the storage facility volumes. The attached "History of Hydrograph Activity" provides a clear sequence of how the storage facility size was determined. The attached calculations are provided in the ' form of "WaterWorks Version 3.1" computer generated output. The attached Tables and Figures are taken from the KCSWDM. t GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report #97-8008 5/ 6/98 GROUP FOUR, Inc. ' Stafford Crest 497-8008 Oversized Wetvault Analysis & Design ----------_____________________________________________________ HISTORY OF HYDROGRAPH ACTIVITY GENERATE HYDROGRAPHS MOVE 2EX to 1 0.9583 cfs 0.7029 ac-ft 9.00 hrs ' MOVE 2DET to 2 3.7691 cfs 1.3319 ac-ft 8.50 hrs MOVE 213Y to 3 ' 0.2672 cfs 0.1038 ac-ft 8.17 hrs MOVE 1 OEX to 4 2.5334 cfs 1.4435 ac-ft 8.83 hrs MOVE 1 ODET to 5 ' 6.5235 cfs 2.2203 ac-ft 8.50 hrs MOVE 1 OBY to 6 ' 0.5287 cfs 0.1868 ac-ft 8.33 hrs MOVE 100EX to 7 ' 4.6554 cfs 2.3825 ac-ft 8.83 hrs MOVE I OODT to 8 9.6401 cfs 3.2412 ac-ft 8.50 hrs ' MOVE 100BY to 9 0.8415 cfs 0.2856 ac-ft 8.33 hrs ' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report #97-8008 5/6/98 GROUP FOUR, Inc. ' Stafford Crest 497-8008 Oversized Wetvault Analysis & Design HISTORY OF HYDROGRAPH ACTIVITY T PERFORM THE LEVEL POOL ROUTING. ADJUST RELEA SE RATES TO ACCOUNT FOR BYPASS FLOWS. LPOOL 1 "2yr Design Storm" .431 2 1 3 10 ' Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 2yr Design Storm 0.43 3.77 1 3 221.85 0.43 10 34601.93 cf ' LPOOL 2 "l0yr Design Storm" 1.54 5 1 3 11 Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume l0yr Design Storm 1.54 6.52 1 3 222.33 1.54 11 37681.81 cf ' LPOOL 3 "100yr Design Storm" 4.32 8 1 3 12 ' Description MatchQ PeakQ Sto Dis PkStg OutQ hyd Volume 100yr Design Storm 4.32 9.64 1 3 222.97 4.32 12 41817.40 cf ' GENERATE POST-DEVELOPED HYDROGRAPHS. ADD CONTROLLED OUTFLOW + BYPASS. ' ADD 10 3 13 0.4778 cfs 1.2920 ac-ft 22.50 hrs ' ADD 11 6 14 1.6727 cfs 2.2514 ac-ft 11.33 lu-s ' ADD 12 9 15 4.6526 cfs 3.3678 ac-ft 9.33 lu-s 1 iGROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE ' Bothell, WA 98011 5/ 6/98 GROUP FOUR, Inc. page 1 ' Stafford Crest #97-8008 Oversized Wetvault Analysis & Design --------------------------------------------------------------------- LEVEL POOL TABLE SUMMARY MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE <--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf) ----------------------------------------------------------------------------- ----------------------------------------------------------------------------- 2yr Design Storm .. 0.43 3.77 1 3 221.85 10 34601.93 cf 10yr Design Storm .. .... ..... 1.54 6.52 1 3 222.33 11 37681.81 cf p E S(G N V'.:�1L.0 M E 100 r Design Storm 4.32 9.64 1 3 222.97 12 41817.40 cf C ' W 30% FPGT0F, OF SAFETY 1.30 4- 1617`+0 GF = 54. 363 CF vat. IeEf��p V/ILUME; PROVIDED - (04)(I00")(6.50�� : 5+1600 CF t r t 4/10/98 GROUP FOUR, Inc . page 2 Stafford Crest #97-8008 R/D Analysis & Design --------------------------------------------------------------------- HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf\AcFt Acres --------------------------------------------- --------------------------------------------- ' 1 0 . 958 540 30620 cf 14 . 54 21(R/24HR PPZ-DEVELO F-D 2 3 . 769 510 58017 cf 13 . 19 2-'I'N2-4HR DETAINED 3 0 . 267 490 4522 cf 1 . 35 2YR/24HR f5`(PP,55 4 2 . 533 530 62880 cf 14 . 54 10YR/24HR PRE-DFVELoPED 5 6 . 523 510 96718 cf 13 . 19 10YR/24HR DETNNED 6 0 . 529 500 8139 cf 1 . 35 IoYR/240 bYPA55 7 4 . 655 530 103780 cf 14 . 54 100YR/24HR ME- DEVELaPEO 8 9 . 640 510 141185 cf 13 . 19 100YR/24HR DETAINED N o 9 0 . 841 500 12439 cf 1 . 35 100YR/2-4HR BYPASS } 10 0 . 431 1450 51756 cf 13 . 19 2YR/24HR CONTROLLED OUrFLOV 0 11 1 . 541 680 89933 cf 13 . 19 IOYR/ZHHR CONTROLLED OUTFLOW 12 4 . 321 560 134264 cf 13 . 19 100\(R/24HR CONTROLLED OUTFLOW 13 0 . 478 1350 56278 cf 14 . 54 2YR/24HR P05T-DEVEL0PED (3+10) 14 1 . 673 680 98072 cf 14 . 54 10YR/24HR Po5T-DEVELOPFD (6+11) ' 15 4 . 653 560 146703 cf 14 . 54 100YR/24HR PoSr DEVELOPED (1+12) 5/ 6/98 GROUP FOUR, Inc. page 2 Stafford Crest #97-8008 Oversized Wetvault Analysis & Design --------------------------------------------------------------------- STAGE STORAGE TABLE ' RECTANGULAR VAULT ID No. 1 Description: Design Detention Vault Length: 100 . 00 ft . Width: 64 . 62 ft . STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> STAGE <----STORAGE----> (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --AC-Ft- (ft) ---cf--- --Ac-Ft- (ft) ---cf--- --Ac-Ft- 216.50 0.0000 0.0000 218.20 10985 0.2522 219.90 21971 0.5044 221.60 32956 0.7566 216.60 646.20 0.0148 218.30 11632 0.2670 220.00 22617 0.5192 221.70 33602 0.7714 216.70 1292 0.0297 218.40 12278 0.2819 220.10 23263 0.5340 221.80 34249 0.7862 216.80 1939 0.0445 218.50 12924 0.2967 220.20 23909 0.5489 221.90 34895 0.8011 ' 216.90 2585 0.0593 218.60 13570 0.3115 220.30 24556 0.5637 222.00 35541 0.8159 217.00 3231 0.0742 218.70 14216 0.3264 220.40 25202 0.5786 222.10 36187 0.8307 217.10 3877 0.0890 218.80 14863 0.3412 220.50 25848 0.5934 222.20 36833 0.8456 217.20 4523 0.1031 218.90 15511 0.3560 220.61 26494 0.6082 222.30 37410 0.8604 ' 217.30 5170 0.1187 219.00 16155 0.3709 220.70 27140 0.6231 222.40 38126 0.8752 217.40 5816 0.1335 219.10 16801 0.3857 220.80 27787 0.6379 222.50 38772 0.6901 217.50 6462 0.1483 219.20 17447 0.4005 220.90 28433 0.6527 222.60 39418 0.9049 ' 217.60 7108 0.1632 219.30 18094 0.4154 221.00 29079 0.6676 222.70 40064 0.9198 217.70 7754 0.1780 219.40 18740 0.4302 221.10 29725 0.6824 222.80 40711 0.9346 217.80 8401 0.1929 219.50 19386 0.4450 221.20 30371 0.6972 222.90 41357 0.9494 ' 217.90 9047 0.2077 219.60 20032 0.4599 221.30 31011 0.7121 223.00 42003 0.9643 218.00 9693 0.2225 219.70 20678 0.4747 221.40 31664 0.7269 218.10 10339 0.2374 219.80 21325 0.4895 221.50 32310 0.7417 5/ 6/98 GROUP FOUR, Inc. page 3 Stafford Crest #97-8008 Oversized Wetvault Analysis & Design STAGE DISCHARGE TABLE MULTIPLE ORIFICE ID No. 1 Description : Outlet E1ev: 216 . 50 Elev: 214 . 50 ft Orifice Diameter: 2 . 6191 in. STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---CfS-- ------- (ft) ---CfS-- ------- --(ft) ---CfS-- ------- (ft) ---CfS-- ------- 216.50 0.0000 218.20 0.2427 219.90 0.3433 221.60 0.4204 216.60 0.0589 218.30 0.2498 220.00 0.3483 221.70 0.4245 216.70 0.0833 218.40 0.2566 220.10 0.3532 221.80 0.4286 216.80 0.1020 218.50 0.2633 220.20 0.3581 221.90 0.4326 ' 216.90 0.1177 218.60 0.2698 220.30 0.3629 222.00 0.4366 217.00 0.1316 218.70 0.2761 220.40 0.3676 222.10 0.4405 217.10 0.1442 218.80 0.2823 220.50 0.3723 222.20 0.4444 217.20 0.1551 218.90 0.2184 220.60 0.3769 222.30 0.4413 ' 217.30 0.1665 219.00 0.2943 220.70 0.3815 222.40 0.4522 217.40 0.1766 219.10 0.3002 220.80 0.3860 222.50 0.4560 217.50 0.1862 219.20 0.3059 220.90 0.3905 222.60 0.4598 ' 217.60 0.1952 219.30 0.3115 221.00 0.3949 222.70 0.4635 217.70 0.2039 219.40 0.3170 221.10 0.3993 222.80 0.4673 217.80 0.2123 219.50 0.3224 221.20 0.4036 222.90 0.4709 ' 217.90 0.2203 219.61 0.3271 221.30 0.4071 223.00 0.4746 218.00 0.2280 219.70 0.3330 221.40 0.4121 218.10 0.2355 219.80 0.3382 221.50 0.4163 r 5/ 6/98 GROUP FOUR, Inc. page 4 Stafford Crest #97-8008 Oversized Wetvault Analysis & Design STAGE DISCHARGE TABLE ' NOTCH WEIR ID No . 2 Description: Notch Weir Weir Length: 1 . 2500 ft . Weir height (p) : 5 . 4000 ft . ' Elevation 221 . 90 ft . Weir Increm: 0 . 10 STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ---Cfs-- ------- (ft) ---Cfs-- ------- (ft) ---Cfs-- ------- (ft) ---Cfs-- ------- 221.90 0.0000 222.20 0.6438 222.50 1.7407 222.80 3.0413 222.00 0.1275 222.30 0.9767 222.60 2.1595 222.90 3.5113 222.10 0.3555 222.40 1.3446 222.70 2.5966 223.00 3.9826 r I 1 1 1 1 5/ 6/98 GROUP FOUR, Inc. page 5 Stafford Crest #97-8008 Oversized Wetvault Analysis & Design STAGE DISCHARGE TABLE COMBINATION DISCHARGE ID No. 3 Description: Structure : 1 Structure : Structure : 2 Structure : Structure : STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> (ft) ___ CfS-- ------- (ft, ---Cfs-- ------- (ft, ---Cfs-- ------- (ft, ---Cfs-- ------- 216.50 0.0000 218.20 0.2927 219.90 0.3433 221.60 0.4204 216.60 0.0589 218.30 0.2498 220.00 0.3483 221.70 0.4245 216.70 0.0833 218.40 0.2566 220.10 0.3532 221.80 0.4286 216.80 0.1020 218.50 0.2633 220.20 0.3581 221.90 0.4326 216.90 0.1177 218.60 0.2698 220.30 0.3629 222.00 0.5641 217.00 0.1316 218.70 0.2761 220.40 0.3676 222.10 0.7910 217.10 0.1442 218.80 0.2823 220.50 0.3723 222.20 1.0882 217.20 0.1558 218.90 0.2884 220.60 0.3769 222.30 1.4250 217.30 0.1665 219.00 0.2943 220.70 0.3815 222.40 1.7968 217.40 0.1766 219.10 0.3002 220.80 0.3860 222.50 2.1967 217.50 0.1862 219.20 0.3059 220.90 0.3905 222.60 2.6193 217.60 0.1952 219.30 0.3115 221.00 0.3949 222.70 3.0602 ' 217.70 0.2039 219.40 0.3170 221.10 0.3993 222.80 3.5156 217.80 0.2123 219.50 0.3224 221.20 0.4036 222.90 3.9822 217.90 0.2203 219.60 0.3278 221.30 0.4078 223.00 4.4572 218.00 0.2280 219.70 0.3130 221.40 0.4121 ' 218.10 0.2355 219.80 0.3382 221.50 0.4163 r i Ie Project Name: 5 T-/-'V F6T'D G 91�51 GR OUP PFOU A Inc. Project No.: 97- M08 16030 Juanita-Woodinville Way NE Date: 21-24 - 96 By: C.O.V, Bothell, Washington 98011 425-775-4581 Sheet:"0\/UGi'ZEQ W&T VP,UL-T Page I Of f ................... .................... ...... .................. ............ ................ ..1. ........ .............. .......... 'A Ulm Ac A�!'Cf 5 IIT� I M F 5 NV 42 e SUP\F _4...................... ......... .. ........ ................................... .................. ............ ...... ..........: ........................... 2. 52 P\� U'LA KI U S Sll Ib'T 0: \A/P'TT" 15 U FRII F,4, F,, 0 2152 A c, .................... ................................. .............. ....................... ............. .......... ................. .......... J 52 A5 1 GAT f ................. T t .. ............. 7 ............. VVP",M RE P�F P� �' I 1 O i N; Ve':�Llu i DF Sil ............... ...........t....... ............ ........... )�Si(�N 1 LUM: D p\E 0; N!C'��f �S F, F_ ............ ............................ ....... . �Cop �EGTI�N1 56) _F6CM ; 30 AGO 19 GO 2 io f 0.4 5 P� V ..........i.. GSiGNI \/OILUM p ay. )va4 00;�� i►z i000: (I ........... L (5 0 r-111, s F,D ri T! PAN WTI ........... VVI LL L5 PK 0 1 b E D b F,La W 1 6F, TH _ j WP�'I` _ aUN L 1 (1, ............................ t f ............... ..................... ............... ... ............ ............. .......... ............ .................... ................................... ......... ............ .......... ....................- ............... ................i .......... ...................................... ........ . ........................................... ..................... ............ ............... ............. C YU ........... ............................................ ............ ..... ..................... ........... ............ ...... ' 2/24/98 GROUP FOUR, Inc . page 1 Stafford Crest ' #97-8008 Oversized Wetvault Analysis & Design BASIN SUMMARY BASIN ID: Pt-wq NAME : Water Quality Design Storm ' SBUH METHODOLOGY TOTAL AREA. . . . . . . : 13 . 19 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 0 . 67 inches AREA. . : 6 . 37 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 18 . 48 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 6 . 82 Acres CN. . . . : 98 . 00 PEAK RATE : 0 . 72 cfs VOL: 0 . 30 Ac-ft TIME : 480 min -- a -1��A � ��.. �►1► �Ir�� ►� . . irIra e o . RED WMIAN ��''� ��i%i ��ram„ � • ME AIR all rag 1� � t oil jklolullin VA Of spa max ` ate. • KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL ' (2) CN values can be area weighted when they apply to pervious areas of similar CN's (within 20 CN points). However, high CN areas should not be combined with low CN areas (unless the low CN areas are less than 15% of the subbasin). In this case, separate hydrographs should be generated and summed to form one hydrograph. FIGURE 3.5.2A HYDROLOGIC SOIL GROUP OF THE SOILS INKING COUNTY ' HYDROLOGIC HYDROLOGIC SOIL GROUP GROUP* SOIL GROUP GROUP* Aldervwood C Orcas Peat D Arents, Alderwood taterial C Oridia D Arents, Everett taterial B Ovall C Beausile C Filchuck C Bellingham D Puget D ' Briscot D Puyallup B Buckley D P,agnar B Coastal Beaches Variable Renton D Earimont Silt Loam D River ash Variable ' Edgev:ick C Salal C Everett A/B 'Sammamish D Indianola A Seattle D Kitsap C Shacar D 1 Klaus C Si Silt C Mixed Alluvial Land Variable Snohomish D Neilton A Sultan C Newberg B Tukwila D Nooksack C Urban Variable Normal Sandy Lcam D Woodinvile D HYDROLOGIC SOIL GROUP CLASSIFICATIONS A. (Low runoff potential). Soils having high infiltration raves, even when thoroughly wetted, and consisting ' chiefly of deep, well-to-excessively drained sands or gravels. These soils have a high rate of water transmission. B. (Moderately low runoff potential). Soils having moderate infiltration rates when thoroughly wetted, and consisting chiefly of moderately fine to moderately coarse textures. These soils have a moderate rate of water transmission. C. (Moderately high runoff potentiai). Soils having slow infiltration rates when thoroughly wetted, and consisting chiefly of soils with a layer that impedes downward movement of water, or soils with moderately fine to fine textures. These soils have a slow rate of water transmission. D. (High runoff potential). Soils having very slow infiltration rates when thoroughly wetted and consisting chiefly of clay soils with a high swelling potential, soils with a permanent high water table, soils with a hardpan or clay layer at or near the surface, and shallow soils over nearly impervious material. These soils have a very slow rate of water transmission. From SCS, TR-55, Second Edition,June 19W. Exhibit A-1. Revisions made from SCS, Soil Interpretation Record, Form #5, September 1988. 3.5.2-2 11/92 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL ' TABLE 3.5?B SCS WESTERN WASHINGTON RUNOFF CURVE NnIBERS SCS WESTERN WASHINGTON RUNOFF CURVE NUMBERS (Published by SCS in 1982) Runoff curve numbers for selected agricultural, suburban and urban land use for Type 1A rainfall distribution, 24-hour storm duration. CURVE NUMBERS BY HYDROLOGIC SOIL GROUP ' LAND USE DESCRIPTION A B C D Cultivated land(1): winter condition 86 91 94 95 ' Mountain open areas: low growing brush and grasslands 74 82 89 92 Meadow or pasture: 65 78 85 89 ' Wood or forest land: undisturbed or older second growth 42 64 76 81 Wood or forest land: young second growth or brush 55 72 81 86 Orchard: with cover crop 81 88 92 94 Open spaces, lawns, parks, golf courses, cemeteries, landscaping. good condition: grass cover on 75% or more of the area 68 80 86 90 ' fair condition: grass cover on 50% to 75% of the area 77 85 90 92 Gravel roads and parking lots 76 85 89 91 Dirt roads and parking lots 72 82 87 89 Impervious surfaces, pavement, roofs, etc. 98 98 98 98 Open water bodies: takes, wetlands, ponds, etc. 100 100 100 100 ' Single Family Residential (2) Dwelling Unit/Gross Acre % Impervious (3) ' 1.0 DU/GA 15 Separate curve number 1.5 DU/GA 20 shall be selected 2.0 DU/GA 25 for pervious and 2.5 DU/GA 30 impervious portion ' 3.0 DU/GA 34 of the site or basin 3.5 DU/GA 38 4.0 DU/GA 42 4.5 DU/GA 46 ' 5.0 DU/GA 48 5.5 DU/GA 50 6.0 DU/GA 52 6.5 DU/GA 54 7.0 DU/GA 56 Planned unit developments, % impervious condominiums, apartments, must be computed commercial business and industrial areas. (1) For a more detailed description of agricultural land use curve numbers refer to National Engineering Handbook, Section 4, Hydrology, Chapter 9, August 1972. (2) Assumes roof and driveway runoff is directed into street/storm system. (3) The remaining pervious areas (lawn) are considered to be in good condition for these curve numbers. 3.5.2-3 , 11/92 KING COUNTY, WAS.HINGTON, SURFACE WATER DESIGN MANUAL.. .-- . _ .: _ TABLE 3.5.2C "n" AND I'V VALUES USED IN TIME CALCULATIONS FOR HYDROGRAPHS ' 'n;Sheet Flow Equation Manning's Values(For the Initial 300 It of travel) n.• ' Smooth surfaces(concrete,asphalt,gravel,or bare hard packed sa) 0.011 Fallow fields or loose soli surface(no residue) 0.0S r Cultivated soil with residue.cover(s<- 0.20 ft/tt) 0.06 Cultivated soli with residue cover(S>0.20 ft/h) 0.17 Shot prairie grass and lawns 0.15 Dense grasses 0.24 ' Bermuda grass 0.41 Range(natural) 0.13 Woods or forest with light underbrush 0.40 Woods or forest with dense underbrush 0.80 *Manning values for sheet flow only,from Overton and Meadows 1976(See TR•55,1%6) ' 'k'Values Used In Travel Time/Time of Concentration Calculations Shallow Concentrated Flow (After the inhial 300 h.of sheet flow,R -0.1) k, 1 1. Forest whh heavy ground liner and meadows(n-0.10) 3 2. Brushy ground whh some trees(n - 0.060) 5 3. Fallow or minimum tillage cultivation(n -0.040) 8 ' 4. High grass(n- 0.035) 9 5. Shot grass,pasture and lawns(n-0.030) 11 e Nearly bare ground(n-0.025) 13 ' 7. Paved and gravel areas(n-0.012) 27 ' Channel Flow(inlermitlent)(At the beginning d visible channels:R-0.2) k, 1. Forested s-ale with heavy ground litter(n - 0.10) 5 2. Forested drainage course/ravine with defined channel bed(n 0.050) 10 ' 3. Rock-lined waterway(n-0035) 15 4. Grassed waterway(n-0.030) 17 S. Earth-lined waterway(n-0,025) 20 6. CMP pipe(n-0.024) 21 7. Concrete pipe(0.012) 42 8. Other waterways and pipes 0.508/n Channel Flow(Continuous stream,R - 0.4) k. ' 9. Meandering stream whh some pools(n-0.040) 20 10. Rock-lined stream(n-0.035) 23 11. Grass-lined stream(n-0.030) 27 12. Other streams,man-made channels and pipe 0.807/n" ' -See Chapter 5,Table 5.3.6C for additional Mannings'n'values for open channels - 1 3.5.2-7 1190 rStafford Crest Techmical Information Report 497-8008 R/D ANALYSIS & DESIGN 100yr Overflow Analysis (Detention Vault— Outfall #213) r GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report 497-8008 100YR OVERFLOW ANALYSIS (Detention Vault—Outfall 9213) ' Flows from the entire Stafford Crest project are not currently tributary to the drainage system located along Lincoln Avenue NE. As a result, a separate, tightline drainage system will be installed as part of the proposed development. In addition, as a portion of the site will be diverted through this system prior to the point of recombination, this proposed conveyance system must be analyzed during the 100-year/24-hour design storm for developed overflow conditions. The 100-year/24-hour developed overflow was calculated to be 9.64 cfs. The 100- year/24-hour developed overflow hydrograph will be routed through the downstream conveyance ' system from the detention vault to Outfall 213, and a Uniform Flow and Backwater Analysis will be performed to verify capacity. In addition to developed overflow from the subject property, this system will also be sized and designed to accommodate flows from upstream off-site areas located along the east side of Lincoln Avenue NE. These areas are part of the natural drainage basin tributary to Lincoln Avenue NE. Upon future development, these areas may drain/hook-up to the proposed Lincoln Avenue NE conveyance system. Per discussions with Ron Straka of the City of Renton, it will be assumed that when these areas eventually develop, they will have detention facilities in place which will provide peak rate runoff control during storms up to and including the 100-year/24- hour design storm. Therefore, these areas will be analyzed for existing conditions. rThis future tributary area consists of approximately 11.31 acres of low density single-family residential development (15% impervious). It will be assumed that the remaining pervious areas are 25% lawn/landscaping in good condition (CN=86), and 75% forest, young second growth, brush and shrubs (CN=81). In addition, approximately 0.79 acres of Lincoln Avenue NE R/W will be included as impervious surfaces (CN=98). For conservative results, it will be assumed ' that flows from this area enter the system at CB#9. See the attached Basin Map for delineation of this tributary area, and refer to the attached Basin Summary for basin input parameters. 1 In summary, the proposed off-site Lincoln Avenue NE conveyance system was sized for on-site, 100-year/24-hour developed overflow, in addition to the future tributary off-site area pre- developed 100-year/24-hour flow. The results of the analysis are provided in the form of ' "WaterWorks Version 3.1" computer generated output. The attached calculations indicate that the proposed off-site conveyance system has adequate capacity to convey 100-year/24-hour developed overflows from the site without overtopping. GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 4/22/98 GROUP FOUR, Inc . page 1 ' Stafford Crest ##97-8008 100yr Overflow Analysis --------------------------------------------------------------------- BASIN SUMMARY ' BASIN ID: 100OF NAME : 100yr-Trib.Off-Site Areas SCS METHODOLOGY TOTAL AREA. . . . . . . : 12 . 10 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE. . . . : TYPEIA PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 9 . 61 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 82 . 47 TIME OF CONC. . . . . : 16 . 73 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 2 . 49 Acres CN. . . . . 98 . 00 TcReach - Sheet L : 300 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 1000 TcReach - Shallow L: 100 . 00 ks : 5 . 00 s : 0 . 1000 PEAK RATE : 6 . 74 cfs VOL: 2 . 37 Ac-ft TIME : 510 min i 1 1 1 1 1 1 1 1 1 /AT rS t .NEvQth S I I IL SE 84th ti N St i o vl L YPSY SUBe ATERSHED NDA Y II I !- t I j st St D LEGEND. ® MODEL SUBBASIN ID E N T R A N G O %'<';.':'�: AREA DRAINING TO Etir�4ERs . n.EWHSn . RAMEQS . stg4fYORs Z STORM DRAIN SYSTEM WASHINGTON ARIZO A cww+Fou K i-r-•• •'••-� SURFACE CONVEYANCE RT. D (Z::::�POND OR SWALE SUBBASIN BOUNDARY HYDROGRAPH Figure 2 FLOW NODE Drainage Features of 500 0 500 the Gypsy Subbasin SCALE IN FEET 5/ 6/98 GROUP FOUR, Inc . page 1 Stafford Crest #97-8008 100yr Overflow Analysis UNIFORM FLOW ANALYSIS ' Network Reach LINE1 REACH <-AREA> <-DIA> LENGTH SLOPE < n > DSGN Q % PIPE Ndepth %Depth Vact Vfull C_Area ' ID (Ac) (ft) (ft) ft/ft ------ (cfs) ------ (ft) ------ (fps) (fps) PVAULT 1.50 62.01 0.0065 0.0120 9.64 97.42 1.31 87.11 5.90 5.75 P10 1.50 300.00 0.0182 0.0120 9.64 58.27 0.86 57.38 9.19 9.61 P9 12.10 1.50 190.00 0.0676 0.0120 16.38 51.32 0.80 53.05 17.21 18.54 1000F P8 12.10 1.50 95.50 0.0796 0.0120 16.38 47.31 0.76 50.53 18.30 20.11 P7 12.10 1.50 197.48 0.1423 0.0120 16.38 35.38 0.64 42.78 22.70 26.89 P6 12.10 1.50 137.46 0.1921 0.0120 16.38 30.46 0.59 39.39 25.33 31.24 P5 12.10 1.50 294.79 0.0663 0.0120 16.38 51.83 0.80 53.37 17.08 18.36 P4 12.10 1.50 138.30 0.0553 0.0120 16.38 56.75 0.85 56.44 15.94 16.76 P3 12.10 1.50 90.65 0.0199 0.0120 16.38 94.72 1.26 83.78 10.36 10.04 P2 12.10 1.50 67.60 0.0340 0.0120 16.38 72.36 0.99 66.33 13.17 13.15 i i 1 ' 5/ 6/98 GROUP FOUR, Inc . page 1 Stafford Crest ' #97-8008 100yr Overflow Analysis --------------------------------------------------------------------- --------------------------------------------------------------------- BACKWATER ANALYSIS Hydraulic Gradeline for Reach HGL1 ' <-FROM-> <--TO--> <FLOW> floss Ent_HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead Headwtr -cb/mh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- ' OUT2B 104.69 CB2 OUT2B 16.38 2.30 tw & do <dc: Inlet Ctrl Assumed 109.59 1.33 0.07 0.00 108.33 109.50 CB3 CB2 16.38 1.87 110.20 0.27 1.33 111.80 111.40 1.33 0.05 0.00 110.52 111.00 CB4 CB3 16.38 2.85 113.37 0.27 1.33 114.97 119.73 1.33 0.03 0.00 118.42 120.90 CBS CB4 16.38 6.08 124.50 0.27 1.33 126.10 139.27 1.33 0.01 0.00 137.94 140.20 CB6 CBS 16.38 2.83 140.78 0.27 1.33 142.38 165.58 1.33 0.01 0.00 164.25 166.60 CB7 CB6 16.38 4.07 168.32 0.27 1.33 169.92 193.71 1.33 0.02 0.00 192.40 193.70 ' CBS CB7 16.38 1.97 194.37 0.27 1.33 195.97 201.36 1.33 1.78 0.00 201.80 202.30 CB9 CBS 16.38 3.92 205.72 0.27 1.33 207.32 214.22 0.46 0.62 0.20 214.57 216.00 CB10 CB9 9.64 2.14 216.71 0.09 0.46 217.27 218.07 0.46 0.62 0.00 218.22 221.60 ' VAULT CB10 9.64 0.44 218.66 0.09 0.46 219.22 218.47 0.00 0.00 0.00 219.22 r t 5/ 6/98 GROUP FOUR, Inc . page 1 ' Stafford Crest #97-8008 100yr Overflow Analysis REACH SUMMARY ' PIPE REACH ID No. P10 From: CB10 To : CB9 Pipe Diameter: 1 . 50 ft n: 0 . 0120 ■ Pipe Length 300 . 00 ft s : 0 . 0182 i Up invert 216 . 10 ft down invert : 210 . 65 Collection Area : Ac . ' Design Flow 9 . 64 cfs Dsgn Depth: 0 . 86 ft Pipe Capacity 16 . 54 cfs Design Vel 9 . 19 fps Travel Time . 0 . 54 min Pipe Full Vel 9 . 61 fps PIPE REACH ID No. P2 From: CB2 To: OUT2B Pipe Diameter : 1 . 50 ft n: 0 . 0120 Pipe Length 67 . 60 ft s : 0 . 0340 ' Up invert 106 . 00 ft down invert : 103 . 70 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 0 . 99 ft ' Pipe Capacity 22 . 64 cfs Design Vel 13 . 17 fps Travel Time : 0 . 09 min Pipe Full Vel 13 . 15 fps PIPE REACH ID No. P3 ' From: CB3 To : CB2 Pipe Diameter: 1 . 50 ft n : 0 . 0120 Pipe Length 90 . 65 ft s : 0 . 0199 ' Up invert 107 . 80 ft down invert : 106 . 00 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 1 . 26 ft ' Pipe Capacity 17 . 30 cfs Design Vel 10 . 36 fps Travel Time : 0 . 15 min Pipe Full Vel 10 . 04 fps PIPE REACH ID No. P4 ' From: C34 To: CB3 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 138 . 30 ft s : 0 . 0553 ' Up invert 116 . 15 ft down invert : 108 . 50 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 0 . 85 ft Pipe Capacity 28 . 87 cfs ' Design Vel 15 . 94 fps Travel Time : 0 . 14 min Pipe Full Vel 16 . 76 fps 5/ 6/98 GROUP FOUR, Inc . page 2 ' Stafford Crest #97-8008 100yr Overflow Analysis REACH SUMMARY ' PIPE REACH ID No. P5 From: C35 To : CB4 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 294 . 79 ft s : 0 . 0663 Up invert 135 . 70 ft down invert : 116 . 15 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 0 . 80 ft Pipe Capacity 31 . 61 cfs Design Vel 17 . 08 fps Travel Time : 0 . 29 min Pipe Full Vel 18 . 36 fps ' PIPE REACH ID No. P6 From: CB6 To: CB5 Pipe Diameter: 1 . 50 ft n: 0 . 0120 1 Pipe Length 137 . 46 ft s : 0 . 1921 Up invert 162 . 10 ft down invert : 135 . 70 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 0 . 59 ft ' Pipe Capacity 53 . 79 cfs Design Vel 25 . 33 fps Travel Time : 0 . 09 min Pipe Full Vel 31 . 24 fps ' PIPE REACH ID No. P7 From: CB7 To : CB6 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 197 .48 ft s : 0 . 1423 ' Up invert 190 . 20 ft down invert : 162 . 10 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 0 . 64 ft ' Pipe Capacity 46 . 30 cfs Design Vel 22 . 70 fps Travel Time : 0 . 14 min Pipe Full Vel 26 . 89 fps PIPE REACH ID No. P8 From: CB8 To : CB7 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 95 . 50 ft s : 0 . 0796 Up invert 197 . 80 ft down invert : 190 . 20 Collection Area : 12 . 10 Ac . Design Flow 16 . 38 cfs Dsgn Depth: 0 . 76 ft Pipe Capacity 34 . 63 cfs ' Design Vel 18 . 30 fps Travel Time : 0 . 09 min Pipe Full Vel 20 . 11 fps 5/ 6/98 GROUP FOUR, Inc . page 3 ' Stafford Crest $#97-8008 100yr Overflow Analysis --------------------------------------------------------------------- REACH SUMMARY ' PIPE REACH ID No. P9 From: C39 To : CB8 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 190 . 00 ft s : 0 . 0676 Up invert 210 . 65 ft down invert : 197 . 80 Collection Area : 12 . 10 Ac . ' Design Flow 16 . 38 cfs Dsgn Depth: 0 . 80 ft Pipe Capacity 31 . 92 cfs Design Vel 17 . 21 fps Travel Time . 0 . 18 min Pipe Full Vel 18 . 54 fps ' PIPE REACH ID No. PVAULT From: VAULT To: CB10 Pipe Diameter: 1 . 50 ft n: 0 . 0120 ' Pipe Length 62 . 01 ft s : 0 . 0065 Up invert 216 . 50 ft down invert : 216 . 10 Collection Area : Ac . Design Flow 9 . 64 cfs Dsgn Depth: 1 . 31 ft Pipe Capacity : 9 . 90 cfs Design Vel 5 . 90 fps Travel Time : 0 . 18 min Pipe Full Vel 5 . 75 fps 1 (3 Project Name: G�,FFOF-D CKST IG ROU PFOU AI nC. Project No.: 97- 600b 16030 Juanita-Woodinville Way NE Date: 2-,- 3 - By: COV Bothell, Washington 98011 425-775-4581 Sheet: 10GY6 OVPF'fLOW 1"WIL"(51 Page of ................................................... ..... ............ ............ ..........................................-- ..... ..... ......... .................................. .......... 645.6K KI I f)F- Q I 1 U,61 TTNcH 0 R 16 F-4� U�7 ............ ............... . ........... .................. ............? c ....... v ........... ........... ............ R M 6 THF, 1 .......... ................... ... ...........1 ...... ............ ..........A I........... ..... ................. ....... ............... EVE L., ........... 6K FIC5 FLOW e...................... ............ ... ............... ............ ............ ........... .......... ..................... ................. ................. .......... ........... tft ........... .........................- ................... ................. .......... ................................... ............... ............ ................. ........... ............?............? ............- ................. ...... ..... ... . ...... .... ......- - 11 ............ ...... .......... ............. ............. .......... ............................................................... ............... . ................... .......... ............. ......................- .......... ................... .................................................................. ....................................................... .......... ...... ............ ......... ................... ........... ............ ............. ........... .............................................................................................. . ............................... ................... ........ ....................... .................. .......... ..................... ...................... -A........................ ....................... ........... .....................1......... .............. .I......... ........... KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL 2/2 FIGURE 4.4.7J RISER rNFLOW CURVES Weir Flow Orifice Flow ----- 36 100 33 30 27 ' C in c 24 21 — 18 U 7 ' 0 15 N cc I . 12 10 ' 10 I t S 3 1 ' 0.1 1.0 10.0 HEAD IN FEET (measured from crest of riser) ' SOURCE: USDA•SCS QWIER = 9.739 DH3`2 0ORIFICE =3.782 DW'2 ' Q in cis, D and H in feet i 4.4.7-10 1/90 r Stafford Crest Techmical Information Report 497-8008 R/D ANALYSIS & DESIGN East Basin Analysis GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 ' Stafford Crest Techmical Information Report #97-8008 R/D ANALYSIS & DESIGN rEast Sub-Basin Analysis r GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 ' R/D ANALYSIS & DESIGN East Sub-Basin Analysis As previously discussed in this report, flows from the east portion of the subject property will be diverted to a detention facility located in the northwest corner of the site. Flow from this vault will be conveyed downstream northerly along Lincoln Avenue NE in a proposed tightline conveyance system to the point where flows from the west sub-basin naturally combine with ' flows from the east sub-basin. This minor sub-basin diversion has been proposed as a result of constraints and anticipated drainage problems located along the existing conveyance system downstream of the east sub-basin. However, just under 5,000 ftz of frontage improvements are proposed along 112"' Place NE which will discharge to this existing system. Therefore, it must be verified that flows tributary to the conveyance system located along 112°i Place NE will not be increased as a result of the required improvements. The total existingon-site area tributary to this downstream ry s ream conveyance system consists of roughly 5.24 acres. This includes 0.02 acres of existing impervious area from NE 36"' Street. The remaining existing on-site area consists of forest land (CN=81). In addition, roughly 0.41 acres of 30' wide R/W (the west half of 112°i Place NE) is also tributary to this system. This frontage area contains a 16' wide existing asphalt roadway (0.22 acres @ CN=98). The remaining frontage area consists of grass shoulder (CN=86). Refer to the attached East Basin Map for delineation of this area, and refer to the attached Basin Summary for detailed basin input parameters for existing conditions. Upon development, 0.16 acres of developed bypass area from the rear yards of Lots 1-7 and Lots ' 71-74 (as shown on the developed basin map) will be tributary to the downstream conveyance system (CN=86). In addition, flow from roughly 0.13 acres of future NE 36" Street R/W will enter the downstream conveyance system. This area consists of 0.02 acres of existing asphalt ' roadway, and 0.08 acres of additional impervious surfaces constructed as part of the proposed development. The remaining 0.03 acres of impervious surfaces will consist of lawns/landscaping (CN=86). The required frontage improvements along 112"' Place NE will result in a total of 0.33 acres of impervious area entering the downstream conveyance system (0.11 acres of additional asphalt paving, curb, gutter and sidewalk). Refer to the attached Basin Summary for detailed basin input parameters for developed conditions. Basins will be created for the on-site east sub-basin and frontage areas separately. The resulting basins will then be combined to generate the required hydrographs. Hydrographs will be generated for the 2-, 10- and 100-year/24-hour design storms, and existing and developed conditions will be compared to evaluate for potential impacts. The attached Hydrograph Summary indicates that the existing flows tributary to the existing downstream conveyance system located along 112'h Place NE will not be exceeded upon development. In addition, and perhaps more importantly, the total volumes of runoff will be significantly reduced. iGROUP FOUR, ILrc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 p_vss�a� SCALE: 1"=100' , FRONTAGE -ONSITE AREA r f , - ; ' / / ( , > t (East Sub- sin) ; , THE OF CONCENTRATION— \ TRAVEL PATH i1 � / � � I .r�i ( , i / •�J "ate_ ��J .. r \ ` p.l077YN J dMIT$- F BASIN T&TARY TO. . 112TH PL. NE 1 , ,WWNSTREAM C,�NVEYANCE 'SYSTEM / ( ' (Areas to be kWo4d as part of 14. j / \� \�"- \\ �.,, \ ' proposed Project �y i , * \ `%. �— - ' 1 - -- --- --,-- -- ------- \ Upsfream' -- --- areas not {'•t (` � � is I ♦ v, ,1 .� it � , --- - - -- �• - ��y�6w - - __47 , a ' , , / NAF ZG JC /' ' i60 tJJ' �` EAST BASIN MAP 3 6 t h 51 -) 59 19'LT� 1 . ;15. 4 30' 1—L N t CB 16 TYPE gp' t, STA. 20+51; 15.19'LT. � 1 TOP 235.58 INV. 231.46(12"IN—S) ' V. 231.21(15 I — o + INV. NE) I 0' .o INV. 231.21(15 OUT—W) CD Via: ;8 N C,?'VC IMFERVIOU6 k 9g l 99 ,t R 0, 03 ---- TD WEsT I 0. gc 0.081tc -- ---- �08 I RDD R X 1 f ' J PERM 5 1NfEfz�lail5 EX .-y" Ce,�'C. \ 7�oo✓ � CB 18 TYP I 7 8 TA. 22+S0 ; 15.1 f I TOR 244.3 5 I INV. _2401 (12„IN—E & S) \ 1 INV. 239. P(15"OUT—W) 35th ; 152LFN15",CP ® 5.72% 1 % . 1 I R=203-I i 4 \ \ / I toU- RB IN SF,% ± ! 30LFN12"SD ��8 , 1; 15.3 I�-fNI, I @ 2.00% I .08u it I _ 30LF'J,2 SD �. 22+0 ; 15.19 RT. + ® 2.00% 244.3 ' 40.7 �� 14 ,`l NE 36TH ST. CONTRIBUTION ' 4/23/98 GROUP FOUR, Inc . page 1 STAFFORD CREST ' #97-8008 East Sub-Basin Analysis --------------------------------------------------------------------- --------------------------------------------------------------------- ' BASIN SUMMARY BASIN ID: 2EXFR NAME : 2yr/24hr Existing Frontage SBUH METHODOLOGY TOTAL AREA. . . . . . . . 0 .41 Acres BASEFLOWS . 0 . 00 cfs RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 19 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 2 . 43 min IMPERVIOUS AREA ' ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 22 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 16 . 00 ns : 0 . 0110 p2yr: 2 . 00 s : 0 . 0200 TcReach - Channel L: 600 . 00 kc : 17 . 00 s : 0 . 0800 PEAK RATE : 0 . 17 cfs VOL: 0 . 05 Ac-ft TIME : 470 min iBASIN ID: 2EXOS NAME : 2yr/24hr On-Site Existing SBUH METHODOLOGY ' TOTAL AREA. . . . . . . : 5 . 24 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 5 . 22 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 56 . 92 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 02 Acres CN. . . . . 98 . 00 ' PEAK RATE: 0 . 27 cfs VOL : 0 . 27 Ac-ft TIME : 520 min 4/23/98 GROUP FOUR, Inc. page 1 STAFFORD CREST #97-8008 East Sub-Basin Analysis BASIN SUMMARY ' BASIN ID: 2DFR NAME: 2yr/24hr Developed Frontage SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 41 Acres BASEFLOWS : 0 . 00 cfs ' RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 08 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 ' TIME OF CONC. . . . . : 1 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 33 Acres CN. . . . . 98 . 00 TcReach - Sheet L: 22 . 00 ns : 0 . 0110 p2yr: 2 . 00 s : 0 . 0200 ' TcReach - Channel L: 440 . 00 kc :42 . 00 s : 0 . 0800 PEAK RATE : 0 . 22 cfs VOL: 0 . 05 Ac-ft TIME : 470 min BASIN ID: 2DO NAME : 2yr/24hr Developed On-Site SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 29 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . . USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0 . 19 Acres ' TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 2 . 58 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 10 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 5000 TcReach - Channel L: 440 . 00 kc :42 . 00 s : 0 . 0800 PEAK RATE : 0 . 10 cfs VOL: 0 . 03 Ac-ft TIME : 470 min 4/23/98 GROUP FOUR, Inc. page 1 STAFFORD CREST #97-8008 East Sub-Basin Analysis BASIN SUMMARY ' BASIN ID: 10EXF NAME : 10yr/24hr Existing Frontage SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 .41 Acres BASEFLOWS : 0 . 00 cfs ' RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 19 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 ' TIME OF CONC. . . . . : 2 .43 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 22 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 16 . 00 ns : 0 . 0110 p2yr: 2 . 00 s : 0 . 0200 TcReach - Channel L: 600 . 00 kc : 17 . 00 s : 0 . 0800 PEAK RATE : 0 . 27 cfs VOL: 0 . 07 Ac-ft TIME : 470 min BASIN ID: 10EXO NAME : 10yr/24hr Existing On-Site ' SBUH METHODOLOGY TOTAL AREA. . . . . . 5 . 24 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 5 . 22 Acres ' TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 56 . 92 min IMPERVIOUS AREA ABSTRACTION COEFF : 0 . 20 AREA. . : 0 . 02 Acres CN. . . . : 98 . 00 PEAK RATE : 0 . 72 cfs VOL: 0 . 54 Ac-ft TIME : 490 min 4/23/98 GROUP FOUR, Inc . page 1 STAFFORD CREST #97-8008 East Sub-Basin Analysis BASIN SUMMARY BASIN ID: 1ODFR NAME : 10yr/24hr Developed Frontage SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 41 Acres BASEFLOWS : 0 . 00 cfs ' RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 08 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 1 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 33 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 22 . 00 ns : 0 . 0110 p2yr: 2 . 00 s : 0 . 0200 TcReach - Channel L: 440 . 00 kc :42 . 00 s : 0 . 0800 PEAK RATE : 0 . 34 cfs VOL : 0 . 08 Ac-ft TIME : 470 min ' BASIN ID: 10DO NAME : 10yr/24hr Developed On-Site SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 29 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0 . 19 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 2 . 58 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 10 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 5000 TcReach - Channel L: 440 . 00 kc :42 . 00 s : 0 . 0800 PEAK RATE : 0 . 17 cfs VOL: 0 . 05 Ac-ft TIME: 470 min 4/23/98 GROUP FOUR, Inc . page 1 STAFFORD CREST #97-8008 East Sub-Basin Analysis BASINSUMMARY=====_______________________ ' BASIN ID: 100EF NAME : 100yr/24hr Existing Frontage SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 41 Acres BASEFLOWS : 0 . 00 cfs ' RAINFALL TYPE. . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 19 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 2 .43 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 22 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 16 . 00 ns : 0 . 0110 p2yr: 2 . 00 s : 0 . 0200 TcReach - Channel L: 600 . 00 kc : 17 . 00 s : 0 . 0800 PEAK RATE : 0 . 40 cfs VOL: 0 . 11 Ac-ft TIME : 470 min BASIN ID: 1OOE0 NAME : 100yr/24hr Existing On-Site SBUH METHODOLOGY TOTAL AREA. . . . . . . 5 . 24 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 5 . 22 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 81 . 00 TIME OF CONC. . . . . : 56 . 92 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 02 Acres ' CN. . . . : 98 . 00 PEAK RATE : 1 . 34 cfs VOL: 0 . 89 Ac-ft TIME : 490 min r 4/23/98 GROUP FOUR, Inc. page 1 STAFFORD CREST #97-8008 East Sub-Basin Analysis BASIN SUMMARY ' BASIN ID: 10ODF NAME : 100yr/24hr Developed Frontage SBUH METHODOLOGY TOTAL AREA. . . . . . . : 0 . 41 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA ' PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 08 Acres TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 1 . 07 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 33 Acres CN. . . . : 98 . 00 TcReach - Sheet L: 22 . 00 ns : 0 . 0110 p2yr: 2 . 00 s : 0 . 0200 TcReach - Channel L: 440 . 00 kc :42 . 00 s : 0 . 0800 PEAK RATE : 0 . 47 cfs VOL: 0 . 12 Ac-ft TIME : 470 min BASIN ID: 100DO NAME : 100yr/24hr Developed On-Site SBUH METHODOLOGY ' TOTAL AREA. . . . . . . : 0 . 29 Acres BASEFLOWS : 0 . 00 cfs RAINFALL TYPE . . . . : USER1 PERVIOUS AREA PRECIPITATION. . . . : 3 . 90 inches AREA. . : 0 . 19 Acres ' TIME INTERVAL. . . . : 10 . 00 min CN. . . . : 86 . 00 TIME OF CONC. . . . . : 2 . 58 min IMPERVIOUS AREA ABSTRACTION COEFF: 0 . 20 AREA. . : 0 . 10 Acres CN. . . . : 98 . 00 ' TcReach - Sheet L: 50 . 00 ns : 0 . 1500 p2yr: 2 . 00 s : 0 . 5000 TcReach - Channel L: 440 . 00 kc :42 . 00 s : 0 . 0800 PEAK RATE : 0 . 26 cfs VOL: 0 . 07 Ac-ft TIME : 470 min r f 4/23/98 GROUP FOUR, Inc . page 1 STAFFORD CREST #97-8008 East Sub-Basin Analysis ------------------ ---------____________ HYDROGRAPH SUMMARY PEAK TIME VOLUME HYD RUNOFF OF OF Contrib NUM RATE PEAK HYDRO Area cfs min. cf\AcFt Acres ---------------------------------- 1 0 . 368 480 13588 cf 5 . 65 2YR/24HR M5TING 2 0 . 318 470 3603 cf 0 . 70 2YR/24HR DEVEL-OPED 3 0 . 898 480 26855 cf 5 . 65 10YR/2'+HR EXISTING 4 0 . 508 470 5713 cf 0 . 70 10YR124HK 1)EVFL_6fED 5 1 . 598 480 43500 cf 5 . 65 I00YR/24HR EX►STING 6 0 . 726 470 8131 cf 0 . 70 100`(R/2_4HR DEVFLopED ' Stafford Crest Techmical Information Report #97-8008 SECTION V Conveyance System Analysis & Design 1 r GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report 497-8008 CONVEYANCE SYSTEM ANALYSIS & DESIGN ' All conveyance systems for proposed projects must be analyzed, designed and constructed using the requirements outlined in Core Requirement #4, Section 1.2.4 of the King County Surface Water Design Manual (KCSWDM). Pipe systems shall be designed to convey and contain at least the peak runoff rate for the 25-year design storm using the Methods of Analysis described in Section 4.3.4 of the KCSWDM. Two methods of hydraulic analysis using Manning's equation are described in Section 4.3.4 of the KCSWDM, and are used sequentially for the design and analysis of pipe systems. First, the Uniform Flow Analysis Method is used for the preliminary design of new pipe systems. Second, the Backwater Analysis Method is used to analyze both proposed, and existing, pipe systems to verify adequate capacity. The Rational Method is used to calculate the required design peak flow rates. Each pipe within the system is sized and ' p p y sloped such that it's barrel capacity at normal full flow ' (computed by Manning's Equation) is equal to or greater then the 25 year design flow. Structures for pipe systems must be demonstrated to provide a minimum of 0.50 feet of freeboard between the hydraulic grade line and the top of the structure for the 25-year peak rate of runoff. IStructures may overtop for the 100-year peak rate of runoff. The attached analysis indicates that the proposed storm water conveyance system is in ' conformance with the requirements outlined in Sections 1.2.4 and 4.3.4 of the KCSWDM. In all cases, the barrel capacity at normal full flow (computed by Manning's Equation) is greater than the 25 year design flow rate (computed using the Rational Method). Also, a minimum 0.50 feet ' of freeboard between the hydraulic grade line and the top of all proposed structures is provided during the 25-year design storm. The calculations do indicate that flow will overtop CB 24, CB 25 and CB 31 during the 100-year design storm, however, it is anticipated that these flows will ' remain within public R/W prior to re-entering the conveyance system at some point downstream. Flows which overtop these structures are not expected to result in any significant adverse 1 impacts. GROUP FOUR,Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 i 1 1 1 1 CONVEYANCE SYSTEM ANALYSIS & DESIGN On-Site System — C13#42 to Vault 1 GROUP FOUR,Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 CONVEYANCE SYSTEM ANALYSIS & DESIGN On-Site System-CB#42 to Vault Catchment Area Summary Table TOTAL ' AREA AREA ROADS LOTS LAWNS ID (acres) c=0.90 c=0.90 c=0.25 ' 11 0.05 0.05 0.00 12 0.51 0.16 0.14 0.21 14 0.04 0.04 0.00 15 0.23 0.08 0.05 0.10 16 0.30 0.07 0.10 0.13 17 0.74 0.23 0.14 0.37 18 0.50 0.07 0.19 0.24 19 0.38 0.07 0.11 0.20 20 0.29 0.08 0.11 0.10 21 0.37 0.08 0.11 0.18 23 0.92 0.14 0.19 0.59 24 0.10 0.10 25 0.26 0.10 0.05 0.11 26 0.41 0.10 0.14 0.17 27 1.14 0.15 0.34 0.65 ' 28 0.29 0.15 0.14 0.00 29 0.81 0.17 0.24 0.40 30 0.36 0.05 0.14 0.17 31 1.11 0.30 0.19 0.62 32 0.43 0.08 0.14 0.21 ' 33 0.79 0.17 0.19 0.43 34 0.68 0.13 0.19 0.36 36 0.46 0.13 0.14 0.19 37 0.10 0.05 0.05 38 0.44 0.11 0.05 0.28 39 0.20 0.06 0.14 40 0.56 0.14 0.10 0.32 ' 41 0.65 0.12 0.19 0.34 42 0.07 0.07 BYPASS 1.35 0.21 1.14 TOTAL 14.54 3.46 3.57 7.51 GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 5/ 7/98 GROUP FOUR, Inc. page 1 ' Stafford Crest 97-8008 Conveyance System Analysis & Design RATIONAL DRAINAGE AREA SUMMARY ' Drainage Area Id: Al2 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) ' Roads 0 . 05 0 . 90 Lot Impervious 0 . 90 Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 Drainage Area Id: Al2A ' Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 16 0 . 90 ' Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 21 0 . 25 Composite "c" Value . . . . . . . . 0 . 63 Time of Conc (min) . . 6 . 30 Drainage Area Id: A14 Description. . . . . . ' <-- -Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 04 0 . 90 Lot Impervious 0 . 90 Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 Drainage Area Id: A15 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) ' Roads 0 . 08 0 . 90 Lot Impervious 0 . 05 0 . 90 Lot Pervious 0 . 10 0 . 25 Composite "c" Value . . . . . . . . 0 . 62 Time of Conc (min) . . 6 . 30 Drainage Area Id: A16 ' Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 07 0 . 90 Lot Impervious 0 . 10 0 . 90 Lot Pervious 0 . 13 0 . 25 Composite "c" Value . . . . . . . . 0 . 62 Time of Conc (min) . . 6 . 30 ' 5/ 7/98 GROUP FOUR, Inc . page 2 Stafford Crest ' 97-8008 Conveyance System Analysis & Design ' RATIONAL DRAINAGE AREA SUMMARY Drainage Area Id: A17 ' Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 23 0 . 90 Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 37 0 . 25 Composite "c" Value . . . . . . . . 0 . 58 Time of Conc (min) . . 6 . 30 Drainage Area Id: A18 Description. . . . . . ' <-- -Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 07 0 . 90 Lot Impervious 0 . 19 0 . 90 Lot Pervious 0 . 24 0 . 25 Composite "c" Value . . . . . . . . 0 . 59 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A19 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 07 0 . 90 Lot Impervious 0 . 11 0 . 90 Lot Pervious 0 . 20 0 . 25 Composite "c" Value . . . . . . . . 0 . 56 Time of Conc (min) . . 6 . 30 Drainage Area Id: A20 Description. . . . . : <---Description- -> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 08 0 . 90 ' Lot Impervious 0 . 11 0 . 90 Lot Pervious 0 . 10 0 . 25 Composite "c" Value . . . . . . . . 0 . 68 Time of Conc (min) . . 6 . 30 Drainage Area Id: A21 Description. . . . . . ' <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 08 0 . 90 Lot Impervious 0 . 11 0 . 90 ' Lot Pervious 0 . 18 0 . 25 Composite "c" Value . . . . . . . . 0 . 58 Time of Conc (min) . . 6 . 30 5/ 7/98 GROUP FOUR, Inc . page 3 Stafford Crest 97-8008 Conveyance System Analysis & Design ' RATIONAL DRAINAGE AREA SUMMARY Drainage Area Id: A23 ' Description. . . . . : <-- -Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 14 0 . 90 ' Lot Impervious 0 . 19 0 . 90 Lot Pervious 0 . 59 0 . 25 Composite "c" Value . . . . . . . . 0 . 48 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A24 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 10 0 . 90 Lot Impervious 0 . 90 ' Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A25 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr- - (min) ' Roads 0 . 10 0 . 90 Lot Impervious 0 . 05 0 . 90 Lot Pervious 0 . 11 0 . 25 Composite "c" Value . . . . . . . . 0 . 62 Time of Conc (min) . . 6 . 30 Drainage Area Id: A26 ' Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 10 0 . 90 Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 17 0 . 25 Composite "c" Value . . . . . . . . 0 . 63 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A27 Description. . . . . . ' <-- -Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 15 0 . 90 Lot Impervious 0 . 34 0 . 90 ' Lot Pervious 0 . 65 0 . 25 Composite "c" Value . . . . . . . . 0 . 53 Time of Conc (min) . . 6 . 30 5/ 7/98 GROUP FOUR, Inc . page 4 Stafford Crest t 97-8008 Conveyance System Analysis & Design ' RATIONAL DRAINAGE AREA SUMMARY Drainage Area Id: A28 Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 15 0 . 90 ' Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 Drainage Area Id: A29 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 17 0 . 90 Lot Impervious 0 . 24 0 . 90 Lot Pervious 0 .40 0 . 25 Composite "c" Value . . . . . . . . 0 . 58 Time of Conc (min) . . 6 . 30 Drainage Area Id: A30 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr- - (min) ' Roads 0 . 05 0 . 90 Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 17 0 . 25 Composite "c" Value . . . . . . . . 0 . 59 Time of Conc (min) . . 6 . 30 Drainage Area Id: A31 ' Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 30 0 . 90 Lot Impervious 0 . 19 0 . 90 Lot Pervious 0 . 62 0 . 25 Composite "c" Value . . . . . . . . 0 . 54 Time of Conc (min) . . 6 . 30 Drainage Area Id: A32 Description. . . . . . ' <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 08 0 . 90 Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 21 0 . 25 Composite "c" Value . . . . . . . . 0 . 58 Time of Conc (min) . . 6 . 30 ' 5/ 7/98 GROUP FOUR, Inc . page 5 Stafford Crest ' 97-8008 Conveyance System Analysis & Design ' RATIONAL DRAINAGE AREA SUMMARY Drainage Area Id: A33 ' Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 17 0 . 90 ' Lot Impervious 0 . 19 0 . 90 Lot Pervious 0 . 43 0 . 25 Composite "c" Value . . . . . . . . 0 . 55 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A34 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 13 0 . 90 Lot Impervious 0 . 19 0 . 90 ' Lot Pervious 0 . 36 0 . 25 Composite "c" Value . . . . . . . . 0 . 56 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A36 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) ' Roads 0 . 13 0 . 90 Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 19 0 . 25 Composite "c" Value . . . . . . . . 0 . 63 Time of Conc (min) . . 6 . 30 Drainage Area Id: A37 ' Description. . . . . : <-- -Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 05 0 . 90 ' Lot Impervious 0 . 05 0 . 90 Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 Drainage Area Id: A38 Description. . . . . . ' <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 11 0 . 90 Lot Impervious 0 . 05 0 . 90 ' Lot Pervious 0 . 28 0 . 25 Composite "c" Value . . . . . . . . 0 . 49 Time of Conc (min) . . 6 . 30 5/ 7/98 GROUP FOUR, Inc . page 6 Stafford Crest t 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- ' RATIONAL DRAINAGE AREA SUMMARY Drainage Area Id: A39 Description. . . . . : <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 06 0 . 90 Lot Impervious 0 . 14 0 . 90 Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 Drainage Area Id: A40 Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 14 0 . 90 Lot Impervious 0 . 10 0 . 90 Lot Pervious 0 . 32 0 . 25 Composite "c" Value . . . . . . . . 0 . 53 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: A41 Description. . . . . . <---Description- -> SubArea SubC L (ft) Slope -Kr- - (min) ' Roads 0 . 12 0 . 90 Lot Impervious 0 . 19 0 . 90 Lot Pervious 0 . 34 0 . 25 ' Composite "c" Value . . . . . . . . 0 . 56 Time of Conc (min) . . 6 . 30 Drainage Area Id: A42 ' Description. . . . . : <- --Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 07 0 . 90 Lot Impervious 0 . 90 Lot Pervious 0 . 25 Composite "c" Value . . . . . . . . 0 . 90 Time of Conc (min) . . 6 . 30 ' Drainage Area Id: BY Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr-- (min) Roads 0 . 21 0 . 90 Lot Impervious 0 . 90 ' Lot Pervious 1 . 14 0 . 25 Composite "c" Value . . . . . . . . 0 . 35 Time of Conc (min) . . Stafford Crest Techmical Information Report 497-8008 t CONVEYANCE SYSTEM ANALYSIS & DESIGN ' On-Site System — C13#42 to Vault 25-year Design Storm 1 1 GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 5/ 7/98 GROUP FOUR, Inc. page 1 ' Stafford Crest 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- ------------- UNIFORM FLOW ANALYSIS Routing based on P3 . 4 family @ 25 yr freq Network LINE2 : ' Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P23 A23 0.92 0.48 0.44 0.44 6.30 2.72 1.21 12 0.024 0.0201 2.74 3.49 3.38 29.84 0.15 Network LINE3 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ' ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P25 A25 0.26 0.62 0.16 0.16 6.30 2.72 0.44 12 0.012 0.0049 2.72 3.46 2.55 42.54 0.28 ' P24 A24 0.10 0.90 0.09 0.25 6.58 2.67 0.67 12 0.012 0.0063 3.07 3.90 3.13 86.00 0.46 Network LINE4 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ' ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P21 A21 0.37 0.58 0.22 0.22 6.30 2.72 0.59 12 0.024 0.0197 2.72 3.46 2.76 30.38 0.18 ' Network LINES : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ' ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P19 A19 0.38 0.56 0.21 0.21 6.30 2.72 0.58 12 0.024 0.0197 2.72 3.46 2.75 30.38 0.18 ' Network LINE6 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P17 A17 0.74 0.58 0.43 0.43 6.30 2.72 1.16 12 0.024 0.0203 2.76 3.51 3.36 30.56 0.15 Network LINE8 : ' Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min ' P38 A38 0.44 0.49 0.21 0.21 6.30 2.72 0.58 12 0.012 0.0049 2.72 3.46 2.76 30.38 0.18 P37 A37 0.10 0.90 0.09 0.31 6.48 2.69 0.82 12 0.012 0.0051 2.75 3.51 3.06 94.81 0.52 ' Network LINES : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P36 A36 0.46 0.63 0.29 0.29 6.30 2.72 0.79 12 0.024 0.0197 2.72 3.46 3.00 30.38 0.17 r 5/ 7/98 GROUP FOUR, Inc. page 2 Stafford Crest 1 97-8008 Conveyance System Analysis & Design UNIFORM FLOW ANALYSIS Network LINE11 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P31 A31 1.11 0.54 0.60 0.60 6.30 2.72 1.62 12 0.024 0.0203 2.76 3.51 3.65 30.56 0.14 Network LINE10 : Pipe Reach Basin Area --c- --c-A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P34 A34 0.68 0.56 0.38 0.38 6.30 2.72 1.03 12 0.024 0.0197 2.72 3.46 3.22 30.38 0.16 P33 A33 0.79 0.55 0.43 0.81 6.46 2.69 2.18 12 0.024 0.0826 5.56 7.08 6.65 155.86 0.39 P32 A32 0.43 0.58 0.25 1.06 6.85 2.62 2.78 12 0.024 0.0742 5.27 6.71 6.80 106.40 0.26 P30 A30 0.36 0.59 0.21 1.87 7.11 2.57 4.61 12 0.012 0.0198 5.44 6.93 7.83 66.19 0.14 Network LINE7 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P42 A42 0.07 0.90 0.06 0.06 6.30 2.72 0.17 12 0.024 0.0197 2.72 3.46 1.93 30.38 0.26 P41 A41 0.65 0.56 0.36 0.43 6.56 2.67 1.14 12 0.024 0.0413 3.93 5.01 4.34 104.06 0.40 P40 A40 0.56 0.53 0.30 0.72 6.96 2.60 1.88 12 0.012 0.0056 2.90 3.69 3.93 62.43 0.27 P39 A39 0.20 0.90 0.18 0.90 7.23 2.55 2.30 12 0.024 0.0702 5.13 6.53 6.35 149.49 0.39 ' P35 1.50 7.62 2.48 3.72 12 0.012 0.0483 8.50 10.83 10.46 320.00 0.51 P29 A29 0.81 0.58 0.47 3.84 8.13 2.38 9.15 15 0.012 0.0431 14.56 11.87 12.54 244.00 0.32 Network LINE12 : ' Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P15 A15 0.23 0.62 0.14 0.14 6.30 2.72 0.39 12 0.024 0.0097 1.90 2.42 1.90 31.05 0.27 P14 A14 0.04 0.90 0.04 0.18 6.57 2.67 0.48 12 0.024 0.0100 1.94 2.46 2.04 87.00 0.71 Network LINE13 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P12A Al2A 0.51 0.63 0.32 0.32 6.30 2.72 0.88 12 0.024 0.0200 2.74 3.48 3.10 30.00 0.16 P12 Al2 0.05 0.90 0.05 0.37 6.46 2.69 0.99 12 0.024 0.0187 2.64 3.37 3.12 67.00 0.36 Network LINE1 : Pipe Reach Basin Area --c- --c*A- --Sum- ---To- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min -- ----------------------- P28 A28 0.29 0.90 0.26 0.26 6.30 2.72 0.71 12 0.024 0.0197 2.72 3.46 2.91 30.38 0.17 P27 A27 1.14 0.53 0.60 0.86 6.47 2.69 2.32 12 0.024 0.0694 5.10 6.49 6.34 204.35 0.54 P26 A26 0.41 0.63 0.26 1.12 7.01 2.59 2.91 12 0.024 0.0354 3.64 4.63 5.15 77.20 0.25 P22 1.82 7.26 2.54 4.63 12 0.012 0.0151 4.75 6.05 6.89 152.68 0.37 P20 A20 0.29 0.68 0.20 2.23 7.63 2.48 5.53 12 0.012 0.0211 5.62 7.15 8.15 149.53 0.31 5/ 7/98 GROUP FOUR, Inc. page 3 Stafford Crest ' 97-8008 Conveyance System Analysis & Design UNIFORM FLOW ANALYSIS P18 All 0.51 0.51 0.29 2.74 7.94 2.42 6.62 15 0.012 0.0573 16.71 13.61 12.87 151.77 0.21 ' P16 A16 0.30 0.62 0.19 3.35 8.13 2.38 7.98 15 0.012 0.0199 9.91 8.07 8.98 66.19 0.12 P13 7.37 8.45 2.32 17.12 24 0.012 0.0847 71.50 22.76 18.69 28.00 0.02 Pil 7.73 8.48 2.32 17.94 24 0.024 0.3000 67.30 21.42 18.13 11.00 0.01 r i 5/ 7/98 GROUP FOUR, Inc. page 1 ' 97-8008 Stafford Crest Conveyance System Analysis & Design BACKWATER-ANALYSIS ' Routing based on P3 . 4 family @ 25 yr freq Hydraulic Gradeline for Reach HGL1 <-FROM-> <--TO--> <FLOW> floss Ent_HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- ' -------- -------- -cfs---loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- OUT11A 223.00 CB11 OUT11A 17.94 0.23 223.23 0.25 0.51 223.99 226.62 0.41 0.61 0.02 226.79 234.98 CB13 CB11 17.12 0.14 226.92 0.09 0.46 227.48 228.57 0.00 0.00 0.00 228.57 235.39 C1316 CB13 7.98 0.86 tw & do <dc: Inlet Ctrl Assumed 233.36 0.45 0.00 0.07 232.98 235.58 CB18 CB16 6.62 1.35 234.33 0.09 0.45 234.88 241.64 0.77 0.15 0.12 241.14 244.37 CB20 CB18 5.53 3.05 244.03 0.15 0.77 244.95 245.47 0.54 0.09 0.08 245.10 250.62 CB22 CB20 4.63 2.18 247.29 0.11 0.54 247.94 247.35 0.00 0.00 0.00 247.94 253.60 CB26 CB22 2.91 1.74 tw & do <dc: Inlet Ctrl Assumed 252.61 0.14 0.00 0.03 252.50 256.33 ' CB27 CB26 2.32 2.95 266.43 0.07 0.14 266.63 266.35 0.01 0.02 0.01 266.65 270.52 CB28 CB27 0.71 0.04 266.94 0.01 0.01 266.96 266.75 0.00 0.00 0.00 266.96 270.52 CB22 249.56 CB23 CB22 1.21 0.12 250.17 0.02 0.04 250.22 249.89 0.00 0.00 0.00 250.22 253.60 CB22 247.94 ' CB24 CB22 0.67 0.03 247.96 0.00 0.01 247.98 246.27 0.00 0.01 0.00 247.98 249.35 CB25 CB24 0.44 0.01 247.98 0.00 0.00 247.99 246.45 0.00 0.00 0.00 247.99 249.35 CB20 245.84 CB21 CB20 0.59 0.03 tw & do <dc: Inlet Ctrl Assumed 246.23 0.00 0.00 0.00 246.23 250.62 CB18 241.14 ' CB19 CB18 0.58 0.03 241.20 0.00 0.01 241.22 240.86 0.00 0.00 0.00 241.22 244.37 CB16 232.98 CB17 CB16 1.16 0.11 233.09 0.02 0.03 233.14 232.27 0.00 0.00 0.00 233.14 235.58 CB13 230.61 C1129 CB13 9.15 4.15 tw & do <dc: Inlet Ctrl Assumed 242.92 0.51 0.77 0.30 243.41 245.15 CB35 CB29 3.72 2.95 246.37 0.07 0.35 246.78 257.47 0.13 0.00 0.05 257.39 263.43 CB39 CB35 2.30 2.12 259.51 0.07 0.13 259.71 266.92 0.09 0.12 0.02 266.97 271.50 CB40 CB39 1.88 0.15 267.54 0.02 0.09 267.65 267.24 0.03 0.00 0.01 267.63 269.95 CB41 CB40 1.14 0.36 271.56 0.02 0.03 271.61 271.42 0.00 0.00 0.00 271.61 275.75 CB42 CB41 0.17 0.00 272.00 0.00 0.00 272.01 271.90 0.00 0.00 0.00 272.01 275.75 ' CB35 257.39 CB37 CB35 0.82 0.04 257.43 0.00 0.02 257.45 256.73 0.01 0.01 0.00 257.46 259.73 CB38 CB37 0.58 0.01 257.46 0.00 0.01 257.47 256.85 0.00 0.00 0.00 257.47 259.73 CB35 258.70 CB36 CB35 0.79 0.05 tw & do <dc: Inlet Ctrl Assumed 259.07 0.00 0.00 0.00 259.07 263.43 CB29 243.41 5/ 7/98 GROUP FOUR, Inc. page 2 Stafford Crest 1 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- BACKWATER ANALYSIS 1 Hydraulic Gradeline for Reach Continued ' <-FROM-> <--TO--> <FLOW> floss Ent_HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- 1 CB30 CB29 4.81 1.02 244.44 0.12 0.58 245.13 243.78 0.19 0.02 0.09 245.04 246.46 CB32 CB30 2.78 2.19 247.23 0.10 0.19 247.52 250.31 0.12 0.03 0.02 250.25 254.35 CB33 CB32 2.18 1.98 tw & do <dc: Inlet Ctrl Assumed 263.03 0.03 0.04 0.02 263.05 267.23 CB34 CB33 1.03 0.09 263.76 0.01 0.03 263.80 213.50 0.00 0.00 0.00 263.80 267.23 CB30 245.04 CB31 CB30 1.62 0.21 245.26 0.03 0.07 245.36 242.83 0.00 0.00 0.00 245.36 246.59 CB13 228.57 CB14 CB13 0.48 0.05 228.90 0.00 0.01 228.90 228.64 0.00 0.00 0.00 228.91 231.92 CB15 CB14 0.39 0.01 229.13 0.00 0.00 229.13 228.93 0.00 0.00 0.00 229.13 231.84 CB11 226.79 CB12 CB11 0.99 0.17 226.96 0.01 0.02 227.00 226.72 0.02 0.03 0.00 227.01 231.05 CB12A CB12 0.88 0.06 227.51 0.01 0.02 227.53 227.30 0.00 0.00 0.00 227.53 231.05 i 1 1 1 1 1 1 1 i 1 5/ 7/98 GROUP FOUR, Inc . page 1 ' Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY Routing based on P3 .4 family @ 25 yr freq PIPE REACH ID No. P11 From: CB11 To: OUT11A Pipe Diameter: 2 . 00 ft n : 0 . 0240 Pipe Length 11 . 00 ft s : 0 . 3000 Up invert 224 . 30 ft down invert : 221 . 00 ft tCollection Area: 13 . 19 Ac . Design Flow 17 . 94 cfs Dsgn Depth: 0 . 74 ft ' Pipe Capacity 67 . 30 cfs Design Vel 18 . 13 fps Travel Time : 0 . 01 min Pipe Full Vel 21 . 42 fps 1 PIPE REACH ID No. P12 From: CB12 To : C311 ' Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 67 . 00 ft s : 0 . 0187 Up invert 226 . 55 ft down invert : 225 . 30 ft Collection Area : 0 . 56 Ac . Design Flow 0 . 99 cfs Dsgn Depth: 0 . 42 ft Pipe Capacity 2 . 64 cfs Design Vel 3 . 12 fps Travel Time : 0 . 36 min Pipe Full Vel 3 . 37 fps MPIPE REACH ID No. P12A From: CB12A To: CB12 ' Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 00 ft s : 0 . 0200 Up invert 227 . 15 ft down invert : 226 . 55 ft Collection Area : 0 . 51 Ac . Design Flow 0 . 88 cfs Dsgn Depth: 0 . 39 ft Pipe Capacity 2 . 74 cfs Design Vel 3 . 10 fps Travel Time : 0 . 16 min Pipe Full Vel 3 .48 fps 5/ 7/98 GROUP FOUR, Inc. page 2 ' Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY ' PIPE REACH ID No. P13 From: CB13 To: CB11 Pipe Diameter : 2 . 00 ft n: 0 . 0120 ' Pipe Length 28 . 00 ft s : 0 . 0847 Up invert 226 . 67 ft down invert : 224 . 30 ft Collection Area : 12 . 63 Ac . ' Design Flow 17 . 12 cfs Dsgn Depth: 0 . 67 ft Pipe Capacity 71 . 50 cfs Design Vel 18 . 69 fps Travel Time : 0 . 02 min ' Pipe Full Vel 22 . 76 fps ' PIPE REACH ID No . P14 From: CB14 To: CB13 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 87 . 00 ft s : 0 . 0100 Up invert 228 . 54 ft down invert : 227 . 67 ft Collection Area : 0 . 27 Ac . ' Design Flow 0 . 48 cfs Dsgn Depth: 0 . 34 ft Pipe Capacity 1 . 94 cfs Design Vel 2 . 04 fps Travel Time : 0 . 71 min ' Pipe Full Vel 2 .46 fps PIPE REACH ID No. P15 t From: CB15 To: C214 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 31 . 05 ft s : 0 . 0097 ' Up invert 228 . 84 ft down invert : 228 . 54 ft Collection Area : 0 . 23 Ac . Design Flow 0 . 39 cfs Dsgn Depth: 0 . 31 ft ' Pipe Capacity 1 . 90 cfs Design Vel 1 . 90 fps Travel Time : 0 . 27 min Pipe Full Vel 2 . 42 fps PIPE REACH ID No. P16 ' From: CB16 To : CB13 Pipe Diameter: 1 . 25 ft n: 0 . 0120 Pipe Length 66 . 19 ft s : 0 . 0199 Up invert 231 . 21 ft down invert : 229 . 89 ft Collection Area : 5 . 70 Ac . Design Flow 7 . 98 cfs Dsgn Depth: 0 . 85 ft Pipe Capacity 9 . 91 cfs Design Vel 8 . 98 fps Travel Time : 0 . 12 min Pipe Full Vel 8 . 07 fps 5/ 7/98 GROUP FOUR, Inc . page 3 Stafford Crest 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- REACH SUMMARY ' PIPE REACH ID No. P17 From: CB17 To: CB16 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 56 ft s : 0 . 0203 Up invert 232 . 08 ft down invert : 231 . 46 ft ' Collection Area : 0 . 74 Ac . Design Flow 1 . 16 cfs Dsgn Depth: 0 . 45 ft Pipe Capacity 2 . 76 cfs Design Vel 3 . 36 fps Travel Time : 0 . 15 min ' Pipe Full Vel 3 . 51 fps ' PIPE REACH ID No. P18 From: CB18 To: CB16 Pipe Diameter: 1 . 25 ft n: 0 . 0120 Pipe Length 151 . 77 ft s : 0 . 0573 ' Up invert 239 . 90 ft down invert : 231 . 21 ft Collection Area : 4 . 66 Ac . ' Design Flow 6 . 62 cfs Dsgn Depth: 0 . 55 ft Pipe Capacity 16 . 79 cfs Design Vel 12 . 87 fps Travel Time : 0 . 20 min Pipe Full Vel 13 . 68 fps PIPE REACH ID No. P19 From: CB19 To : CB18 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 ' Up invert 240 . 75 ft down invert : 240 . 15 ft Collection Area : 0 . 38 Ac . ' Design Flow 0 . 58 cfs Dsgn Depth: 0 . 31 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 75 fps Travel Time . 0 . 18 min Pipe Full Vel 3 .46 fps PIPE REACH ID No . P20 ' From: CB20 To: C318 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 149 . 53 ft s : 0 . 0211 Up invert 243 . 30 ft down invert : 240 . 15 ft Collection Area : 3 . 78 Ac . Design Flow 5 . 53 cfs Dsgn Depth: 0 . 81 ft ' Pipe Capacity 5 . 62 cfs Design Vel 8 . 15 fps Travel Time : 0 . 31 min Pipe Full Vel 7 . 15 fps 5/ 7/98 GROUP FOUR, Inc . page 4 ' Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P21 From: CB21 To : CB20 Pipe Diameter: 1 . 00 ft n: 0 . 0240 ' Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 246 . 12 ft down invert : 245 . 52 ft Collection Area : 0 . 37 Ac . Design Flow 0 . 59 cfs Dsgn Depth: 0 . 32 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 76 fps Travel Time : 0 . 18 min Pipe Full Vel 3 .46 fps ' PIPE REACH ID No. P22 From: CB22 To: CB20 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 152 . 68 ft s : 0 . 0151 ' Up invert 245 . 60 ft down invert : 243 . 30 ft Collection Area : 3 . 12 Ac . Design Flow 4 . 63 cfs Dsgn Depth: 0 . 80 ft Pipe Capacity 4 . 75 cfs Design Vel 6 . 89 fps Travel Time : 0 . 37 min Pipe Full Vel 6 . 05 fps PIPE REACH ID No. P23 From: CB23 To : CB22 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 29 . 84 ft s : 0 . 0201 Up invert 249 . 70 ft down invert : 249 . 10 ft Collection Area: 0 . 92 Ac . Design Flow 1 . 21 cfs Dsgn Depth: 0 . 46 ft Pipe Capacity 2 . 74 cfs Design Vel 3 . 38 fps Travel Time : 0 . 15 min Pipe Full Vel 3 .49 fps PIPE REACH ID No. P24 From: CB24 To: C1122 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 86 . 00 ft s : 0 . 0063 Up invert 246 . 14 ft down invert : 245 . 60 ft Collection Area : 0 . 36 Ac . Design Flow 0 . 67 cfs Dsgn Depth: 0 . 32 ft Pipe Capacity 3 . 07 cfs Design Vel 3 . 13 fps Travel Time : 0 . 46 min Pipe Full Vel 3 . 90 fps 5/ 7/98 GROUP FOUR, Inc . page 5 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P25 From: CB25 To: CB24 Pipe Diameter: 1 . 00 ft n: 0 . 0120 ' Pipe Length 42 . 54 ft s : 0 . 0049 Up invert 246 . 35 ft down invert : 246 . 14 ft Collection Area : 0 . 26 Ac . Design Flow 0 . 44 cfs Dsgn Depth: 0 . 27 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 55 fps Travel Time : 0 . 28 min Pipe Full Vel 3 . 46 fps PIPE REACH ID No. P26 From: CB26 To: CB22 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 77 . 20 ft s : 0 . 0354 ' Up invert 251 . 83 ft down invert : 249 . 10 ft Collection Area : 1 . 84 Ac . ' Design Flow 2 . 91 cfs Dsgn Depth: 0 . 68 ft Pipe Capacity 3 . 64 cfs Design Vel 5 . 15 fps Travel Time : 0 . 25 min ' Pipe Full Vel 4 . 63 fps PIPE REACH ID No. P27 ' From: CB27 To: CB26 Pipe Diameter : 1 . 00 ft n: 0 . 0240 Pipe Length 204 . 35 ft s : 0 . 0694 ' Up invert 266 . 02 ft down invert : 251 . 83 ft Collection Area: 1 .43 Ac. Design Flow 2 . 32 cfs Dsgn Depth: 0 .47 ft Pipe Capacity 5 . 10 cfs Design Vel 6 . 34 fps Travel Time . 0 . 54 min Pipe Full Vel 6 . 49 fps PIPE REACH ID No. P28 ' From: CB28 To : CB27 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 266 . 62 ft down invert : 266 . 02 ft Collection Area : 0 . 29 Ac . Design Flow 0 . 71 cfs Dsgn Depth: 0 . 35 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 91 fps Travel Time : 0 . 17 min Pipe Full Vel 3 .46 fps 5/ 7/98 GROUP FOUR, Inc . page 6 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P29 From: CB29 To : CB13 Pipe Diameter: 1 . 25 ft n: 0 . 0120 Pipe Length 244 . 00 ft s : 0 . 0431 Up invert 240 .40 ft down invert : 229 . 89 ft ' Collection Area : 6 . 66 Ac . Design Flow 9 . 15 cfs Dsgn Depth: 0 . 72 ft Pipe Capacity 14 . 56 cfs Design Vel 12 . 54 fps Travel Time : 0 . 32 min Pipe Full Vel 11 . 87 fps PIPE REACH ID No. P30 From: CB30 To: CB29 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 66 . 19 ft s : 0 . 0198 Up invert 241 . 96 ft down invert : 240 . 65 ft Collection Area : 3 . 37 Ac . Design Flow 4 . 81 cfs Dsgn Depth: 0 . 73 ft Pipe Capacity 5 . 44 cfs Design Vel 7 . 83 fps Travel Time : 0 . 14 min Pipe Full Vel 6 . 93 fps PIPE REACH ID No. P31 From: CB31 To : C230 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 56 ft s : 0 . 0203 Up invert 242 . 58 ft down invert : 241 . 96 ft Collection Area : 1 . 11 Ac . ' Design Flow 1 . 62 cfs Dsgn Depth: 0 . 55 ft Pipe Capacity 2 . 76 cfs Design Vel 3 . 65 fps Travel Time : 0 . 14 min Pipe Full Vel 3 . 51 fps PIPE REACH ID No . P32 From: CB32 To: CB30 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 106 . 40 ft s : 0 . 0742 Up invert 249 . 85 ft down invert : 241 . 96 ft Collection Area : 1 . 90 Ac . Design Flow 2 . 78 cfs Dsgn Depth: 0 . 52 ft Pipe Capacity 5 . 27 cfs Design Vel 6 . 80 fps Travel Time : 0 . 26 min Pipe Full Vel 6 . 71 fps 5/ 7/98 GROUP FOUR, Inc . page 7 ' Stafford Crest 97-8008 Conveyance System Analysis & Design ' REACH SUMMARY ' PIPE REACH ID No. P33 From: CB33 To : C332 Pipe Diameter : 1 . 00 ft n: 0 . 0240 ' Pipe Length 155 . 86 ft s : 0 . 0826 Up invert 262 . 73 ft down invert : 249 . 85 ft Collection Area: 1 .47 Ac . Design Flow 2 . 18 cfs Dsgn Depth: 0 . 44 ft Pipe Capacity 5 . 56 cfs Design Vel 6 . 65 fps Travel Time : 0 . 39 min Pipe Full Vel 7 . 08 fps PIPE REACH ID No. P34 From: CB34 To : CB33 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 263 . 33 ft down invert : 262 . 73 ft Collection Area : 0 . 68 Ac . Design Flow 1 . 03 cfs Dsgn Depth: 0 . 43 ft Pipe Capacity 2 . 72 cfs Design Vel 3 . 22 fps Travel Time : 0 . 16 min ' Pipe Full Vel 3 .46 fps PIPE REACH ID No. P35 From: CB35 To: CB29 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 320 . 00 ft s : 0 . 0483 Up invert 256 . 10 ft down invert : 240 . 65 ft Collection Area : 2 .48 Ac . ' Design Flow 3 . 72 cfs Dsgn Depth: 0 . 46 ft Pipe Capacity 8 . 50 cfs Design Vel 10 .46 fps Travel Time . 0 . 51 min Pipe Full Vel 10 . 83 fps PIPE REACH ID No. P36 From: CB36 To : CB35 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 258 . 93 ft down invert : 258 . 33 ft Collection Area : 0 .46 Ac . Design Flow 0 . 79 cfs Dsgn Depth: 0 . 37 ft Pipe Capacity 2 . 72 cfs Design Vel 3 . 00 fps Travel Time : 0 . 17 min Pipe Full Vel 3 .46 fps 5/ 7/98 GROUP FOUR, Inc . page 8 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No . P37 From: CB37 To : CB35 Pipe Diameter: 1 . 00 ft n: 0 . 0120 ' Pipe Length 94 . 81 ft s : 0 . 0051 Up invert 256 . 58 ft down invert : 256 . 10 ft Collection Area : 0 . 54 Ac . Design Flow 0 . 82 cfs Dsgn Depth: 0 . 38 ft Pipe Capacity 2 . 75 cfs Design Vel 3 . 06 fps Travel Time : 0 . 52 min Pipe Full Vel 3 . 51 fps PIPE REACH ID No. P38 From: C238 To : CB37 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 30 . 38 ft s : 0 . 0049 Up invert 256 . 73 ft down invert : 256 . 58 ft Collection Area : 0 .44 Ac . ' Design Flow 0 . 58 cfs Dsgn Depth: 0 . 31 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 76 fps Travel Time : 0 . 18 min ' Pipe Full Vel 3 . 46 fps PIPE REACH ID No. P39 ' From: CB39 To : CB35 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 149 .49 ft s : 0 . 0702 Up invert 266 . 60 ft down invert : 256 . 10 ft Collection Area : 1 .48 Ac. ' Design Flow 2 . 30 cfs Dsgn Depth: 0 . 47 ft Pipe Capacity 5 . 13 cfs Design Vel 6 . 35 fps Travel Time . 0 . 39 min Pipe Full Vel 6 . 53 fps PIPE REACH ID No. P40 From: CB40 To: CB39 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 62 .43 ft s : 0 . 0056 Up invert 266 . 95 ft down invert : 266 . 60 ft Collection Area: 1 . 28 Ac . Design Flow 1 . 88 cfs Dsgn Depth: 0 . 59 ft Pipe Capacity 2 . 90 cfs Design Vel 3 . 93 fps Travel Time : 0 . 27 min Pipe Full Vel 3 . 69 fps 5/ 7/98 GROUP FOUR, Inc . page 9 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P41 From: CB41 To: CB40 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 104 . 06 ft s : 0 . 0413 Up invert 271 . 25 ft down invert : 266 . 95 ft Collection Area: 0 . 72 Ac . Design Flow 1 . 14 cfs Dsgn Depth: 0 . 37 ft Pipe Capacity 3 . 93 cfs Design Vel 4 . 34 fps Travel Time : 0 . 40 min Pipe Full Vel 5 . 01 fps PIPE REACH ID No. P42 From: C342 To: CB41 Pipe Diameter: 1 . 00 ft n: 0 . 0240 ' Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 271 . 85 ft down invert : 271 . 25 ft Collection Area : 0 . 07 Ac . ' Design Flow 0 . 17 cfs Dsgn Depth: 0 . 17 ft Pipe Capacity 2 . 72 cfs Design Vel 1 . 93 fps Travel Time : 0 . 26 min Pipe Full Vel 3 . 46 fps r ' Stafford Crest Techmical Information Report #97-8008 r CONVEYANCE SYSTEM ANALYSIS & DESIGN On-Site System — C13#42 to Vault 100-year Design Storm 1 GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 5/ 7/98 GROUP FOUR, Inc. page 1 Stafford Crest 97-8008 Conveyance System Analysis & Design ' UNIFORM FLOW ANALYSIS Routing based on P3 . 9 family @ 100 yr freq Network LINE2 : ' Pipe Reach Basin Area --c- --c*A- --Sum- ---To- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min ' P23 A23 0.92 0.48 0.44 0.44 6.30 3.20 1.42 12 0.024 0.0201 2.74 3.49 3.53 29.84 0.14 Network LINE3 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P25 A25 0.26 0.62 0.16 0.16 6.30 3.20 0.52 12 0.012 0.0049 2.72 3.46 2.67 42.54 0.27 P24 A24 0.10 0.90 0.09 0.25 6.57 3.14 0.79 12 0.012 0.0063 3.07 3.90 3.28 86.00 0.44 Network LINE4 : Pipe Reach Basin Area --c- --c*A- --Sum- ---To- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ' ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P21 A21 0.37 0.58 0.22 0.22 6.30 3.20 0.69 12 0.024 0.0197 2.72 3.46 2.89 30.38 0.18 Network LINES : Pipe Reach Basin Area --c- --c*A- --Sum- ---To- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ' ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P19 A19 0.38 0.56 0.21 0.21 6.30 3.20 0.68 12 0.024 0.0197 2.72 3.46 2.88 30.38 0.18 ' Network LINE6 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P17 A17 0.74 0.58 0.43 0.43 6.30 3.20 1.36 12 0.024 0.0203 2.76 3.51 3.50 30.56 0.15 Network LINE8 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P38 A38 0.44 0.49 0.21 0.21 6.30 3.20 0.68 12 0.012 0.0049 2.72 3.46 2.88 30.38 0.18 P37 A37 0.10 0.90 0.09 0.31 6.48 3.16 0.97 12 0.012 0.0051 2.75 3.51 3.20 94.81 0.49 Network LINES : Pipe Reach Basin Area --c- --c*A- --Sum- ---To- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P36 A36 0.46 0.63 0.29 0.29 6.30 3.20 0.93 12 0.024 0.0197 2.72 3.46 3.14 30.38 0.16 ' 5/ 7/98 GROUP FOUR, Inc. page 2 Stafford Crest ' 97-8008 Conveyance System Analysis & Design ' UNIFORM FLOW ANALYSIS ' Network LINE11 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P31 A31 1.11 0.54 0.60 0.60 6.30 3.20 1.91 12 0.024 0.0203 2.76 3.51 3.79 30.56 0.13 Network LINE10 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ------ Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min t P34 A34 0.68 0.56 0.38 0.38 6.30 3.20 1.21 12 0.024 0.0197 2.72 3.46 3.36 30.38 0.15 P33 A33 0.79 0.55 0.43 0.81 6.45 3.17 2.56 12 0.024 0.0826 5.56 7.08 6.94 155.86 0.37 P32 A32 0.43 0.58 0.25 1.06 6.83 3.08 3.27 12 0.024 0.0742 5.27 6.71 7.07 106.40 0.25 ' P30 A30 0.36 0.59 0.21 1.87 7.08 3.03 5.66 12 0.012 0.0198 5.44 6.93 7.21 66.19 0.15 Network LINE7 : ' Pip=-Reach-Basin ---=Area-====-==c=A=---Sum---m - _i -QAct-Dia--Mann-=Slope--QFull-Vfull-=Vat==Lexigth-=Id ac c*A- in in/hr cfs in -n-- ft/ft cfs fps fps f min P42 A42 0.07 0.90 0.06 0.06 6.30 3.20 0.20 12 0.024 0.0197 2.72 3.46 2.03 30.38 0.25 ' P41 A41 0.65 0.56 0.36 0.43 6.55 3.14 1.34 12 0.024 0.0413 3.93 5.01 4.53 104.06 0.38 P40 A40 0.56 0.53 0.30 0.72 6.93 3.06 2.21 12 0.012 0.0056 2.90 3.69 4.06 62.43 0.26 P39 A39 0.20 0.90 0.18 0.90 7.19 3.00 2.71 12 0.024 0.0702 5.13 6.53 6.62 149.49 0.38 ' P35 1.50 7.56 2.92 4.38 12 0.012 0.0483 8.50 10.83 10.91 320.00 0.49 P29 A29 0.81 0.58 0.47 3.84 8.05 2.81 10.79 15 0.012 0.0431 14.56 11.87 12.99 244.00 0.31 Network LINE12 : ' Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min P15 A15 0.23 0.62 0.14 0.14 6.30 3.20 0.45 12 0.024 0.0097 1.90 2.42 1.99 31.05 0.26 P14 A14 0.04 0.90 0.04 0.18 6.56 3.14 0.56 12 0.024 0.0100 1.94 2.46 2.13 87.00 0.68 Network LINE13 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min ' P12A Al2A 0.51 0.63 0.32 0.32 6.30 3.20 1.03 12 0.024 0.0200 2.74 3.48 3.24 30.00 0.15, P12 Al2 0.05 0.90 0.05 0.37 6.45 3.17 1.16 12 0.024 0.0187 2.64 3.37 3.26 67.00 0.34 Network LINE1 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min -------------------------------------- -- ' P28 A28 0.29 0.90 0.26 0.26 6.30 3.20 0.84 12 0.024 0.0197 2.72 3.46 3.05 30.38 0.17 P27 A27 1.14 0.53 0.60 0.86 6.47 3.16 2.73 12 0.024 0.0694 5.10 6.49 6.61 204.35 0.52 P26 A26 0.41 0.63 0.26 1.12 6.98 3.05 3.42 12 0.024 0.0354 3.64 4.63 5.27 77.20 0.24 ' P22 1.82 7.23 2.99 5.45 12 0.012 0.0151 4.75 6.05 6.94 152.68 0.37 P20 A20 0.29 0.68 0.20 2.23 7.59 2.91 6.50 12 0.012 0.0211 5.62 7.15 8.28 149.53 0.30 5/ 7/98 GROUP FOUR, Inc . page 3 Stafford Crest 97-8008 Conveyance System Analysis & Design -----------------------UNIFORM FLOW ANALYSIS ------------------------ P18 1111 0.50 0.59 0.29 2.74 7.89 2.85 7.79 15 0.012 0.0573 16.79 13.68 13.43 151.77 0.19 P16 A16 0.30 0.62 0.19 3.35 8.08 2.81 9.39 15 0.012 0.0199 9.91 8.07 9.19 66.19 0.12 P13 7.37 8.37 2.74 20.20 24 0.012 0.0847 71.50 22.76 19.57 28.00 0.02 Pil 7.73 8.39 2.74 21.16 24 0.024 0.3000 67.30 21.42 18.97 11.00 0.01 5/ 7/98 GROUP FOUR, Inc. page 1 Stafford Crest 97-8008 Conveyance System Analysis & Design BACKWATER.ANALYSIS t Routing based on P3 . 9 family @ 100 yr freq Hydraulic Gradeline for Reach HGL1 <-FROM-> <--TO--> <FLOW> floss Ent_HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- ' -------- -------= --cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- OUT11A 223.00 ' CB11 OUT11A 21.16 0.33 223.33 0.35 0.70 224.38 227.10 0.64 0.85 0.03 227.34 234.98 CB13 CB11 20.20 0.19 227.53 0.13 0.64 228.30 229.27 0.00 0.00 0.00 229.27 235.39 CB16 CB13 9.39 1.19 tw & do <dc: Inlet Ctrl Assumed 233.83 0.63 0.01 0.10 233.31 235.58 CB18 CB16 7.79 1.87 235.11 0.13 0.63 235.93 241.97 1.06 0.21 0.16 241.27 244.37 CB20 CB18 6.50 4.22 245.50 0.21 1.06 246.77 246.03 0.75 0.12 0.11 246.26 250.62 CB22 CB20 5.45 3.03 249.29 0.15 0.75 250.19 247.74 0.00 0.00 0.00 250.19 253.60 CB26 CB22 3.42 2.42 252.60 0.15 0.30 253.05 253.22 0.19 0.01 0.04 253.07 256.33 CB27 CB26 2.73 4.08 257.16 0.09 0.19 257.44 266.42 0.02 0.02 0.02 266.44 270.52 CB28 CB27 0.84 0.06 266.98 0.01 0.02 267.00 266.77 0.00 0.00 0.00 267.00 270.52 CB22 250.19 CB23 CB22 1.42 0.16 250.35 0.03 0.05 250.42 249.92 0.00 0.00 0.00 250.42 253.60 CB22 250.19 ' CB24 CB22 0.79 0.04 250.22 0.00 0.02 250.24 246.29 0.01 0.01 0.00 250.25 249.35 CB25 CB24 0.52 0.01 250.25 0.00 0.01 250.26 246.46 0.00 0.00 0.00 250.26 249.35 -- ' CB20 246.26 CB21 CB20 0.69 0.04 246.46 0.01 0.01 246.48 246.25 0.00 0.00 0.00 246.48 250.62 CB18 241.27 CB19 CB18 0.68 0.04 241.31 0.01 0.01 241.33 240.88 0.00 0.00 0.00 241.33 244.37 CB16 233.31 CB17 CB16 1.36 0.15 233.46 0.02 0.05 233.53 232.29 0.00 0.00 0.00 233.53 235.58 CB13 230.69 CB29 CB13 10.79 5.77 tw & do <dc: Inlet Ctrl Assumed 243.56 0.81 1.07 0.42 244.24 245.15 CB35 CB29 4.38 4.10 248.34 0.10 0.48 248.92 257.72 0.19 0.00 0.07 257.61 263.43 CB39 CB35 2.71 2.94 260.55 0.09 0.19 260.83 266.99 0.12 0.16 0.02 267.06 271.50 CB40 CB39 2.21 0.20 267.61 0.02 0.12 267.75 267.29 0.05 0.00 0.02 267.73 269.95 ' CB41 CB40 1.34 0.50 271.59 0.02 0.05 271.66 271.45 0.00 0.00 0.00 271.66 275.75 CB42 CB41 0.20 0.00 272.02 0.00 0.00 272.02 271.91 0.00 0.00 0.00 272.02 275.75 CB35 257.61 CB37 CB35 0.97 0.06 257.67 0.00 0.02 257.70 256.75 0.01 0.02 0.00 257.71 259.73 CB38 CB37 0.68 0.01 257.72 0.00 0.01 257.73 256.87 0.00 0.00 0.00 257.73 259.73 ' CB35 258.73 CB36 CB35 0.93 0.07 tw & do <dc: Inlet Ctrl Assumed 259.09 0.00 0.00 0.00 259.09 263.43 CB29 244.24 5/ 7/98 GROUP FOUR, Inc . page 2 Stafford Crest ' 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- BACKWATER ANALYSIS Hydraulic Gradeline for Reach Continued ' <-FROM-> <--TO--> <FLOW> floss Ent_HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- CB30 CB29 5.66 1.42 245.66 0.16 0.81 246.63 244.21 0.27 0.02 0.12 246.50 246.46 CB32 CB30 3.27 3.04 249.53 0.13 0.27 249.94 251.16 0.17 0.05 0.03 251.07 254.35 CB33 CB32 2.56 2.74 253.81 0.08 0.17 254.06 263.09 0.04 0.05 0.02 263.13 267.23 ' CB34 CB33 1.21 0.12 263.80 0.02 0.04 263.85 263.52 0.00 0.01 0.00 263.85 267.23 CB30 246.50 CB31 CB30 1.91 0.30 246.80 0.05 0.09 246.93 242.87 0.00 0.00 0.00 246.93 246.59 ' CB13 229.27 CB14 CB13 0.56 0.07 229.34 0.00 0.01 229.36 228.66 0.01 0.01 0.00 229.36 231.92 ' CB15 CB14 0.45 0.02 229.39 0.00 0.01 229.39 228.94 0.00 0.00 0.00 229.39 231.84 CB11 227.34 ' CB12 CB11 1.16 0.24 227.58 0.02 0.03 227.63 226.74 0.03 0.04 0.00 227.64 231.05 CB12A CB12 1.03 0.09 227.73 0.01 0.03 227.77 227.32 0.00 0.00 0.00 227.77 231.05 1 r 5/ 7/98 GROUP FOUR, Inc . page 1 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY t Routing based on P3 . 9 family @ 100 yr freq PIPE REACH ID No. P11 From: CB11 To : OUT11A Pipe Diameter: 2 . 00 ft n: 0 . 0240 Pipe Length 11 . 00 ft s : 0 . 3000 Up invert 224 . 30 ft down invert : 221 . 00 ft ' Collection Area : 13 . 19 Ac . Design Flow 21 . 16 cfs Dsgn Depth: 0 . 80 ft Pipe Capacity 67 . 30 cfs Design Vel 18 . 97 fps Travel Time : 0 . 01 min Pipe Full Vel 21 . 42 fps ' PIPE REACH ID No. P12 From: CB12 To : CB11 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 67 . 00 ft s : 0 . 0187 Up invert 226 . 55 ft down invert . 225 . 30 ft Collection Area : 0 . 56 Ac . Design Flow 1 . 16 cfs Dsgn Depth: 0 . 46 ft Pipe Capacity 2 . 64 cfs ' Design Vet 3 . 26 fps Travel Time : 0 . 34 min Pipe Full Vel 3 . 37 fps ' PIPE REACH ID No. P12A From: C312A To: C312 Pipe Diameter: 1 . 00 ft n: 0 . 0240 ' Pipe Length 30 . 00 ft s : 0 . 0200 Up invert 227 . 15 ft down invert : 226 . 55 ft Collection Area: 0 . 51 Ac . Design Flow 1 . 03 cfs Dsgn Depth: 0 . 43 ft Pipe Capacity 2 . 74 cfs Design Vel 3 . 24 fps Travel Time : 0 . 15 min Pipe Full Vel 3 . 48 fps r 5/ 7/98 GROUP FOUR, Inc . page 2 r Stafford Crest 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- rREACH SUMMARY r PIPE REACH ID No. P13 From: CB13 To : CB11 Pipe Diameter: 2 . 00 ft n: 0 . 0120 r Pipe Length 28 . 00 ft s : 0 . 0847 Up invert 226 . 67 ft down invert : 224 . 30 ft Collection Area : 12 . 63 Ac . Design Flow 20 . 20 cfs Dsgn Depth: 0 . 73 ft Pipe Capacity 71 . 50 cfs Design Vel 19 . 57 fps Travel Time : 0 . 02 min rPipe Full Vel 22 . 76 fps ' PIPE REACH ID No. P14 From: C314 To : C213 Pipe Diameter. 1 . 00 ft n: 0 . 0240 Pipe Length 87 . 00 ft s : 0 . 0100 ' Up invert 228 . 54 ft down invert : 227 . 67 ft Collection Area: 0 . 27 Ac . r Design Flow 0 . 56 cfs Dsgn Depth: 0 . 37 ft Pipe Capacity 1 . 94 cfs Design Vel 2 . 13 fps Travel Time : 0 . 68 min Pipe Full Vel 2 . 46 fps 1 PIPE REACH ID No. P15 ' From: CB15 To : C314 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 31 . 05 ft s : 0 . 0097 Up invert 228 . 84 ft down invert : 228 . 54 ft Collection Area : 0 . 23 Ac . Design Flow 0 .45 cfs Dsgn Depth: 0 . 33 ft Pipe Capacity 1 . 90 cfs Design Vel 1 . 99 fps Travel Time : 0 . 26 min Pipe Full Vel 2 .42 fps r PIPE REACH ID No. P16 ' From: C316 To : CB13 Pipe Diameter: 1 . 25 ft n: 0 . 0120 Pipe Length 66 . 19 ft s : 0 . 0199 Up invert 231 . 21 ft down invert : 229 . 89 ft ' Collection Area : 5 . 70 Ac . Design Flow 9 . 39 cfs Dsgn Depth: 0 . 97 ft Pipe Capacity 9 . 91 cfs Design Vel 9 . 19 fps Travel Time : 0 . 12 min Pipe Full Vel 8 . 07 fps 1 5/ 7/98 GROUP FOUR, Inc . page 3 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P17 From: CB17 To : C216 Pipe Diameter: 1 . 00 ft n : 0 . 0240 ' Pipe Length 30 . 56 ft s : 0 . 0203 Up invert 232 . 08 ft down invert : 231 . 46 ft Collection Area : 0 . 74 Ac . Design Flow 1 . 36 cfs Dsgn Depth: 0 . 50 ft Pipe Capacity 2 . 76 cfs Design Vel 3 . 50 fps Travel Time : 0 . 15 min Pipe Full Vel 3 . 51 fps ' PIPE REACH ID No . P18 From: CB18 To : C316 Pipe Diameter: 1 . 25 ft n: 0 . 0120 Pipe Length 151 . 77 ft s : 0 . 0573 Up invert 239 . 90 ft down invert : 231 . 21 ft Collection Area: 4 . 66 Ac . ' Design Flow 7 . 79 cfs Dsgn Depth: 0 . 60 ft Pipe Capacity 16 . 79 cfs Design Vel 13 .43 fps Travel Time : 0 . 19 min ' Pipe Full Vel 13 . 68 fps PIPE REACH ID No . P19 ' From: CB19 To: CB18 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 240 . 75 ft down invert : 240 . 15 ft Collection Area : 0 . 38 Ac . Design Flow 0 . 68 cfs Dsgn Depth: 0 . 34 ft ' Pipe Capacity 2 . 72 cfs Design Vel 2 . 88 fps Travel Time : 0 . 18 min Pipe Full Vel 3 .46 fps PIPE REACH ID No. P20 From: C1320 To: CB18 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 149 . 53 ft s : 0 . 0211 Up invert 243 . 30 ft down invert : 240 . 15 ft Collection Area : 3 . 78 Ac . Design Flow 6 . 50 cfs Dsgn Depth: ft 1 Pipe Capacity 5 . 62 cfs Design Vel 8 . 28 fps Travel Time : 0 . 30 min Pipe Full Vel 7 . 15 fps (surcharged tt) 5/ 7/98 GROUP FOUR, Inc. page 4 Stafford Crest 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- REACH SUMMARY PIPE REACH ID No. P21 From: CB21 To: CB20 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 246 . 12 ft down invert : 245 . 52 ft Collection Area : 0 . 37 Ac . Design Flow 0 . 69 cfs Dsgn Depth: 0 . 34 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 89 fps Travel Time : 0 . 18 min Pipe Full Vel 3 . 46 fps PIPE REACH ID No. P22 From: CB22 To: C320 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 152 . 68 ft s : 0 . 0151 Up invert 245 . 60 ft down invert : 243 . 30 ft Collection Area: 3 . 12 Ac . Design Flow 5 . 45 cfs Dsgn Depth: ft Pipe Capacity 4 . 75 cfs Design Vel 6 . 94 fps Travel Time : 0 . 37 min ' Pipe Full Vel 6 . 05 fps (surcharged tt) PIPE REACH ID No. P23 From: CB23 To: CB22 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 29 . 84 ft s : 0 . 0201 Up invert 249 . 70 ft down invert : 249 . 10 ft Collection Area: 0 . 92 Ac . Design Flow 1 .42 cfs Dsgn Depth: 0 . 51 ft ' Pipe Capacity 2 . 74 cfs Design Vel 3 . 53 fps Travel Time : 0 . 14 min Pipe Full Vel 3 . 49 fps PIPE REACH ID No. P24 ' From: CB24 To : CB22 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 86 . 00 ft s : 0 . 0063 Up invert 246 . 14 ft down invert : 245 . 60 ft ICollection Area: 0 . 36 Ac . Design Flow 0 . 79 cfs Dsgn Depth: 0 . 35 ft Pipe Capacity 3 . 07 cfs Design Vel 3 . 28 fps Travel Time : 0 . 44 min Pipe Full Vel 3 . 90 fps 5/ 7/98 GROUP FOUR, Inc . page 5 Stafford Crest 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- REACH SUMMARY PIPE REACH ID No. P25 From: CB25 To : CB24 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 42 . 54 ft s : 0 . 0049 Up invert 246 . 35 ft down invert : 246 . 14 ft Collection Area : 0 . 26 Ac . Design Flow 0 . 52 cfs Dsgn Depth: 0 . 30 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 67 fps Travel Time : 0 . 27 min 1 Pipe Full Vel 3 .46 fps ' PIPE REACH ID No. P26 From: CB26 To : CB22 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 77 . 20 ft s : 0 . 0354 Up invert 251 . 83 ft down invert : 249 . 10 ft Collection Area : 1 . 84 Ac . Design Flow 3 .42 cfs Dsgn Depth: 0 . 77 ft Pipe Capacity 3 . 64 cfs Design Vel 5 . 27 fps Travel Time : 0 . 24 min ' Pipe Full Vel 4 . 63 fps PIPE REACH ID No. P27 I From: CB27 To: C1326 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 204 . 35 ft s : 0 . 0694 Up invert 266 . 02 ft down invert : 251 . 83 ft Collection Area : 1 .43 Ac . Design Flow 2 . 73 cfs Dsgn Depth: 0 . 52 ft Pipe Capacity 5 . 10 cfs Design Vel 6 . 61 fps Travel Time : 0 . 52 min Pipe Full Vel 6 . 49 fps PIPE REACH ID No. P28 From: CB28 To : CB27 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 266 . 62 ft down invert : 266 . 02 ft Collection Area : 0 . 29 Ac . Design Flow 0 . 84 cfs Dsgn Depth: 0 . 38 ft Pipe Capacity 2 . 72 cfs Design Vel 3 . 05 fps Travel Time : 0 . 17 min Pipe Full Vel 3 .46 fps 5/ 7/98 GROUP FOUR, Inc . page 6 Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P29 From: CB29 To : C313 Pipe Diameter : 1 . 25 ft n: 0 . 0120 Pipe Length 244 . 00 ft s : 0 . 0431 Up invert 240 . 40 ft down invert : 229 . 89 ft Collection Area : 6 . 66 Ac . Design Flow 10 . 79 cfs Dsgn Depth: 0 . 80 ft Pipe Capacity 14 . 56 cfs Design Vel 12 . 99 fps Travel Time : 0 . 31 min ' Pipe Full Vel 11 . 87 fps PIPE REACH ID No. P30 From: CB30 To: CB29 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 66 . 19 ft s : 0 . 0198 Up invert 241 . 96 ft down invert : 240 . 65 ft Collection Area : 3 . 37 Ac . Design Flow 5 . 66 cfs Dsgn Depth: ft Pipe Capacity 5 . 44 cfs Design Vel 7 . 21 fps Travel Time : 0 . 15 min ' Pipe Full Vel 6 . 93 fps (surcharged tt) PIPE REACH ID No. P31 ' From: C331 To: CB30 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 56 ft s : 0 . 0203 ' Up invert 242 . 58 ft down invert : 241 . 96 ft Collection Area : 1 . 11 Ac . Design Flow 1 . 91 cfs Dsgn Depth: 0 . 61 ft Pipe Capacity 2 . 76 cfs Design Vel 3 . 79 fps Travel Time : 0 . 13 min Pipe Full Vel 3 . 51 fps PIPE REACH ID No. P32 From: CB32 To : CB30 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 106 . 40 ft s : 0 . 0742 Up invert 249 . 85 ft down invert : 241 . 96 ft Collection Area : 1 . 90 Ac . Design Flow 3 . 27 cfs Dsgn Depth: 0 . 57 ft Pipe Capacity 5 . 27 cfs Design Vel 7 . 07 fps Travel Time : 0 . 25 min Pipe Full Vel 6 . 71 fps 5/ 7/98 GROUP FOUR, Inc . page 7 Stafford Crest 97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- REACH SUMMARY ' PIPE REACH ID No. P33 From: C333 To : CB32 Pipe Diameter: 1 . 00 ft n: 0 . 0240 ' Pipe Length 155 . 86 ft s : 0 . 0826 Up invert 262 . 73 ft down invert : 249 . 85 ft Collection Area : 1 .47 Ac . Design Flow 2 . 56 cfs Dsgn Depth: 0 . 48 ft Pipe Capacity 5 . 56 cfs Design Vel 6 . 94 fps Travel Time : 0 . 37 min ' Pipe Full Vel 7 . 08 fps ' PIPE REACH ID No. P34 From: CB34 To: C333 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 ' Up invert 263 . 33 ft down invert : 262 . 73 ft Collection Area : 0 . 68 Ac . ' Design Flow 1 . 21 cfs Dsgn Depth: 0 . 47 ft Pipe Capacity 2 . 72 cfs Design Vel 3 . 36 fps Travel Time : 0 . 15 min Pipe Full Vel 3 .46 fps PIPE REACH ID No. P35 From: C235 To : CE29 Pipe Diameter : 1 . 00 ft n: 0 . 0120 Pipe Length 320 . 00 ft s : 0 . 0483 ' Up invert 256 . 10 ft down invert : 240 . 65 ft Collection Area : 2 .48 Ac . Design Flow 4 . 38 cfs Dsgn Depth: 0 . 51 ft Pipe Capacity 8 . 50 cfs Design Vel 10 . 91 fps Travel Time . 0 . 49 min Pipe Full Vel 10 . 83 fps PIPE REACH ID No. P36 From: CB36 To: C335 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 258 . 93 ft down invert : 258 . 33 ft ' Collection Area : 0 . 46 Ac . Design Flow 0 . 93 cfs Dsgn Depth: 0 .40 ft ' Pipe Capacity 2 . 72 cfs Design Vel 3 . 14 fps Travel Time : 0 . 16 min Pipe Full Vel 3 .46 fps 5/ 7/98 GROUP FOUR, Inc . page 8 ' Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY ' PIPE REACH ID No. P37 From: CB37 To : CB35 Pipe Diameter: 1 . 00 ft n: 0 . 0120 ' Pipe Length 94 . 81 ft s : 0 . 0051 Up invert 256 . 58 ft down invert : 256 . 10 ft ' Collection Area: 0 . 54 Ac . Design Flow 0 . 97 cfs Dsgn Depth: 0 . 41 ft Pipe Capacity 2 . 75 cfs Design Vel 3 . 20 fps Travel Time : 0 . 49 min ' Pipe Full Vel 3 . 51 fps ' PIPE REACH ID No. P38 From: CB38 To: C337 Pipe Diameter : 1 . 00 ft n: 0 . 0120 ' Pipe Length 30 . 38 ft s : 0 . 0049 Up invert 256 . 73 ft down invert : 256 . 58 ft Collection Area : 0 . 44 Ac . Design Flow : 0 . 68 cfs Dsgn Depth: 0 . 34 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 88 fps Travel Time : 0 . 18 min ' Pipe Full Vel 3 .46 fps PIPE REACH ID No. P39 From: C339 To: CB35 Pipe Diameter: 1 . 00 ft n : 0 . 0240 Pipe Length 149 . 49 ft s : 0 . 0702 ' Up invert 266 . 60 ft down invert : 256 . 10 ft Collection Area : 1 . 48 Ac . ' Design Flow 2 . 71 cfs Dsgn Depth: 0 . 52 ft Pipe Capacity 5 . 13 cfs Design Vel 6 . 62 fps Travel Time . 0 . 38 min Pipe Full Vel 6 . 53 fps PIPE REACH ID No. P40 From: C340 To: C239 Pipe Diameter: 1 . 00 ft n: 0 . 0120 Pipe Length 62 .43 ft s : 0 . 0056 Up invert 266 . 95 ft down invert : 266 . 60 ft ' Collection Area : 1 . 28 Ac . Design Flow 2 . 21 cfs Dsgn Depth: 0 . 65 ft Pipe Capacity : 2 . 90 cfs Design Vel 4 . 06 fps Travel Time : 0 . 26 min Pipe Full Vel 3 . 69 fps 5/ 7/98 GROUP FOUR, Inc . page 9 ' Stafford Crest 97-8008 Conveyance System Analysis & Design REACH SUMMARY PIPE REACH ID No. P41 From: CB41 To: CB40 Pipe Diameter: 1 . 00 ft n: 0 . 0240 ' Pipe Length 104 . 06 ft s : 0 . 0413 Up invert 271 . 25 ft down invert : 266 . 95 ft t Collection Area : 0 . 72 Ac . Design Flow 1 . 34 cfs Dsgn Depth: 0 . 40 ft Pipe Capacity 3 . 93 cfs Design Vel 4 . 53 fps Travel Time : 0 . 38 min ' Pipe Full Vel 5 . 01 fps ' PIPE REACH ID No. P42 From: C342 To : CB41 Pipe Diameter: 1 . 00 ft n: 0 . 0240 Pipe Length 30 . 38 ft s : 0 . 0197 Up invert 271 . 85 ft down invert : 271 . 25 ft Collection Area : 0 . 07 Ac . ' Design Flow 0 . 20 cfs Dsgn Depth: 0 . 18 ft Pipe Capacity 2 . 72 cfs Design Vel 2 . 03 fps Travel Time : 0 . 25 min ' Pipe Full Vel 3 . 46 fps Stafford Crest Techmical Information Report 497-8008 CONVEYANCE SYSTEM ANALYSIS & DESIGN Off-Site System — 112"' Place NE (Intake #45A — Outfall #43B) GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 3/ 3/98 GROUP FOUR, Inc . page 1 Stafford Crest #97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- RATIONAL DRAINAGE AREA SUMMARY ' Drainage Area Id: A45A Description. . . . . . <---Description--> SubArea SubC L (ft) Slope -Kr- - (min) 5 DU/GA 8 . 50 0 . 54 300 . 00 0 . 0200 7 . 00 5 . 05 1000 . 00 0 . 1000 15 . 00 3 . 51 Composite "c" Value . . . . . . . . 0 . 54 Time of Conc (min) . . 8 . 56 r r *Ev 40th S I _� r l�- ► SE 8 4 t h Llo y 6 t-h = St 4h I + 14il �11 �t- YPSY SUBS �C _ ATERSHED NDA -� m 0CN SE 9 st t LEGEND• AREA DRAINING TO ® MODEL SUBBASIN ID E N T R A N .0 O STORM DRAIN SYSTEM �""S7 ' RS ..•-,.•,. r..;..,' W/StIiNGION MfZONA GLIfORNU SURFACE CONVEYANCE RT. POND OR SWALE SUBBASIN BOUNDARY FLOW HYDRONODE GRAPH Figure 2 Drainage Features of 500 , 0 500 1000 the Gypsy Subbasin SCALE IN FEET 3/ 3/98 GROUP FOUR, Inc. page 1 ' ##97-8008 Stafford Crest Conveyance System Analysis & Design ' UNIFORM FLOW ANALYSIS Routing based on P3 .4 family @ 25 yr freq Network LINE1 : Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min ' P45A A45A 8.50 0.54 4.51 4.59 8.56 2.30 10.57 18 0.012 0.1162 38.90 22.01 18.73 29.00 0.03 P45 4.59 8.59 2.30 10.55 18 0.012 0.0827 32.82 18.57 16.54 91.00 0.09 P44 4.59 8.68 2.28 10.48 18 0.012 0.0770 31.66 17.91 16.08 281.00 0.29 P43 4.59 8.97 2.23 10.23 18 0.012 0.0625 28.52 16.14 14.81 150.00 0.17 1 I 3/ 3/98 GROUP FOUR, Inc . page 1 Stafford Crest #97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- BACKWATER ANALYSIS Routing based on P3 .4 family @ 25 yr freq ' Hydraulic Gradeline for Reach HGL1 - <-FROM-> <--TO--> <FLOW> floss Ent HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- OUT43B 220.52 CB43 OUT43B 10.23 1.21 tw & do <dc: Inlet Ctrl Assumed 231.31 0.55 0.00 -0.01 230.76 232.77 CB44 CB43 10.48 2.37 251.37 0.11 0.55 252.02 252.98 0.55 0.00 -0.00 252.42 254.40 CB45 CB44 10.55 0.78 253.20 0.11 0.55 253.87 260.52 0.56 0.00 -0.00 259.96 261.93 IN45A CB45 10.57 0.25 260.21 0.11 0.56 260.88 263.87 0.00 0.00 0.00 263.87 264.80 3/ 3/98 GROUP FOUR, Inc. page 1 ' Stafford Crest $#97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- ' REACH SUMMARY ' Routing based on P3 . 4 family @ 25 yr freq PIPE REACH ID No. P43 ' From: CB43 To : OUT43B Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 150 . 00 ft s : 0 . 0625 Up invert 229 . 27 ft down invert : 219 . 90 ft Collection Area : 8 . 50 Ac . Design Flow 10 . 23 cfs Dsgn Depth: 0 . 62 ft Pipe Capacity 28 . 52 cfs Design Vel 14 . 81 fps Travel Time : 0 . 17 min Pipe Full Vel 16 . 14 fps PIPE REACH ID No. P44 From: C344 To : CB43 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 281 . 00 ft s : 0 . 0770 Up invert 250 . 90 ft down invert : 229 . 27 ft Collection Area : 8 . 50 Ac . Design Flow 10 .48 cfs Dsgn Depth: 0 . 60 ft Pipe Capacity 31 . 66 cfs Design Vel 16 . 08 fps Travel Time : 0 . 29 min Pipe Full Vel 17 . 91 fps PIPE REACH ID No. P45 From: CB45 To : C344 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 91 . 00 ft s : 0 . 0827 Up invert 258 . 43 ft down invert : 250 . 90 ft Collection Area : 8 . 50 Ac . Design Flow 10 . 55 cfs Dsgn Depth: 0 . 59 ft Pipe Capacity 32 . 82 cfs ' Design Vet 16 . 54 fps Travel Time : 0 . 09 min Pipe Full Vel 18 . 57 fps 3/ 3/98 GROUP FOUR, Inc . page 2 ! Stafford Crest #97-8008 Conveyance System Analysis & Design --------------------------------------------------------------------- --------------------------------------------------------------------- ! REACH SUMMARY ' PIPE REACH ID No. P45A From: IN45A To: CB45 Pipe Diameter: 1 . 50 ft n: 0 . 0120 ! Pipe Length 29 . 00 ft s : 0 . 1162 Up invert 261 . 80 ft down invert : 258 . 43 ft Collection Area : 8 . 50 Ac . ! Design Flow 10 . 57 cfs Dsgn Depth: 0 . 54 ft Pipe Capacity 38 . 90 cfs Design Vel 18 . 73 fps Travel Time : 0 . 03 min Pipe Full Vel 22 . 01 fps ! ! 3/ 3/98 GROUP FOUR, Inc. page 1 1 #97-8008 Stafford Crest Conveyance System Analysis & Design --------------------------------------------------------------------- ! -----------------------UNIFORM FLOW ANALYSIS------------------------ iRouting based on P3 . 9 family @ 100 yr freq Network LINE1 : i Pipe Reach Basin Area --c- --c*A- --Sum- ---Tc- --i-- --QAct Dia -Mann -Slope -QFull Vfull -Vact -Length --tt-- ---------- Id ac --c*A- - min in/hr cfs in --n-- ft/ft cfs fps fps ft min 1 P45A A45A 8.50 0.54 4.59 4.59 8.56 2.70 12.31 18 0.012 0.1162 38.90 22.01 19.55 29.00 0.12 P45 4.59 8.59 2.69 12.36 18 0.012 0.0827 32.82 18.57 17.26 91.00 0.09 P44 4.59 8.68 2.67 12.27 18 0.012 0.0770 31.66 17.91 16.78 281.00 0.28 P43 4.59 8.96 2.61 11.99 18 0.012 0.0625 28.52 16.14 15.44 150.00 0.16 1 i i 1 1 1 1 1 i i 3/ 3/98 GROUP FOUR, Inc . page 1 ' #97-8008 Stafford Crest Conveyance System Analysis & Design ' BACKWATER ANALYSIS ' Routing based on P3 . 9 family @ 100 yr freq Hydraulic Gradeline for Reach HGL1 <-FROM-> <--TO--> <FLOW> floss Ent_HGL EntLoss ExtLoss OutLet Inlet AppHead BndHead JunHead HeadWtr -cb/mh- ' -------- -------- cfs -loss- -Elev-- --loss- --loss- --Elev- --Elev- --loss- --loss- --loss- --Elev- --Rim-- OUT43B 220.58 C1143 OUT43B 11.99 1.66 tw & do <dc: Inlet Ctrl Assumed 231.68 0.75 0.00 -0.01 230.92 232.77 CB44 CB43 12.27 3.25 234.16 0.15 0.75 235.06 253.36 0.76 0.00 -0.00 252.60 254.40 CB45 CB44 12.36 1.07 253.67 0.15 0.76 254.58 260.91 0.76 0.00 -0.00 260.14 261.93 IN45A CB45 12.38 0.34 260.49 0.15 0.76 261.40 264.26 0.00 0.00 0.00 264.26 264.80 t 1 3/ 3/98 GROUP FOUR, Inc. page 1 ' Stafford Crest #97-8008 Conveyance System Analysis & Design REACH SUMMARY Routing based on P3 . 9 family @ 100 yr freq PIPE REACH ID No. P43 From: CB43 To : OUT43B Pipe Diameter: 1 . 50 ft n : 0 . 0120 Pipe Length 150 . 00 ft s : 0 . 0625 ' Up invert 229 . 27 ft down invert : 219 . 90 ft Collection Area : 8 . 50 Ac . Design Flow 11 . 99 cfs Dsgn Depth: 0 . 68 ft ' Pipe Capacity 28 . 52 cfs Design Vel 15 . 44 fps Travel Time : 0 . 16 min Pipe Full Vel 16 . 14 fps ' PIPE REACH ID No. P44 ' From: C344 To: CB43 Pipe Diameter : 1 . 50 ft n: 0 . 0120 Pipe Length 281 . 00 ft s : 0 . 0770 Up invert 250 . 90 ft down invert : 229 . 27 ft ' Collection Area : 8 . 50 Ac . Design Flow 12 . 27 cfs Dsgn Depth: 0 . 65 ft Pipe Capacity 31 . 66 cfs Design Vel 16 . 78 fps Travel Time : 0 . 28 min Pipe Full Vel 17 . 91 fps PIPE REACH ID No. P45 From: C245 To: CB44 ' Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 91 . 00 ft s : 0 . 0827 Up invert 258 . 43 ft down invert : 250 . 90 ft ' Collection Area : 8 . 50 Ac . Design Flow 12 . 36 cfs Dsgn Depth: 0 . 64 ft Pipe Capacity 32 . 82 cfs ' Design Vel 17 . 26 fps Travel Time : 0 . 09 min Pipe Full Vel 18 . 57 fps 3/ 3/98 GROUP FOUR, Inc . page 2 ' Stafford Crest #97-8008 Conveyance System Analysis & Design REACH SUMMARY ' PIPE REACH ID No. P45A From: IN45A To: CB45 Pipe Diameter: 1 . 50 ft n: 0 . 0120 Pipe Length 29 . 00 ft s : 0 . 1162 Up invert 261 . 80 ft down invert : 258 . 43 ft Collection Area : 8 . 50 Ac . t Design Flow 12 . 38 cfs Dsgn Depth: 0 . 59 ft Pipe Capacity 38 . 90 cfs Design Vel 19 . 55 fps Travel Time : 0 . 02 min ' Pipe Full Vel 22 . 01 fps 1 r ' Stafford Crest Techmical Information Report #97-8008 1 SECTION VI ' Special Reports & Studies GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 SPECIAL REPORTS & STUDIES "Preliminary Geotechnical Report" Terra Associates, Inc. Project No.T-3685 July 10, 1997 t GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 SECTION VII Basin and Community Plan Areas GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 BASIN AND COMMUNITY PLAN AREAS The subject property is located in the Gypsy Sub-Basin and the Newcastle Community Planning Area. It does not appear as though the project is subject to any specific development limitations or restrictions associated with these Basin and Community Planning Areas. GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Jiit ' AR j REEK _ LOOUALMIE j if AST °fir ti oY r s I STL _ - "-'r-c%- � KING i '` y "� _ ✓.g ` - t� COUNTY = — k _ j AVEN HEI _HtS � � C Figure 1 I' .• 1. _ , `,„ _ � .....,.. - -�.-, KING COUNTY 1 -- _'� "" r COMMUNITY PLANNING AREAS e _ \`/ _—.r- ♦ ' ./ ' King County ♦/ moor _ a. 'y �`•—\. 1 a c w \ - --- -- -- -r - � t _ems; ' o I z 3 4 e s z awn.. It 300.000 LN ' Stafford Crest Techmical Information Report 497-8008 ' SECTION VIII Other Permits ' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 Stafford Crest Techmical Information Report #97-8008 N/ A ' GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE ' Bothell, WA 98011 ' Stafford Crest Techmical Information Report #97-8008 ' SECTION IX Temporary Erosion and Sedimentation Control Analysis & Design GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE ' Bothell,WA 98011 GROUPFOUR Inc• Project Name: GT-\F FORD GP\EST _7 ' 16030 Juanita-Woodinville Way NE Project No.: 9 7- 8 Q Of5I Bothell, Washington 98011 Date: 4'Z I ' 9 g By: C O V FAX(206)362-3819 (425)775-4581•(206)362-4244 Sheet: G E D I M F N T- F0[\,I D S I z I N G Page of 2 --3 .�_77._c s_ �FF,0M T I -F,..__GEG ON i D E SIGN _ !S(AFPIGC, A K F A_ R O O_ 00 f+ 3.77 of 7) 8 2- - --cf_s___-__ DESIGN _ Gg1,m R1_ 3,5 M N_I M UM D P TH F-Ko -P f O F R ►S F R l a._ , — DE5(GN, _sUIZA__GE P.R_Ef __P __ V (0 HWL) = 7 85�_f T I _ Stafford Crest Techmical Information Report 497-8008 ' SECTION X Bond Quantities Worksheet R/D Facility Summary Sheet & Sketch ' Declaration of Covenant GROUP FOUR, hic. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 KING COUNTY, WASHINGTON, SURFACE WATER DESIGN MANUAL RETENTIOWDETENTION SUMMARY SHEET Development 'Z1-P•FFoI%D GIZE'ST Date 3. 3•98 ' Location ' ENGINEER DEVELOPER Name G6R11 E14 0. Vi\- N 1 E 121 Name ST'AFFORD HOMES Firm GRouP FOWf ) ING. Firm CONTRGT: R013 PUKSEK ' Address 16030 TVJ^NIT^-WDPIVLE' WA'I' N6 Address 16016 - 118TH FL-AGE NF, BOT ELL wA 011 SOTHELL , ONA 98011 Phone �J25 -45 Phone l'88 - 2222 P ' Develo ed Site 14,, 5t acres Number of Lots 7� ' • Number of Detention Facilities On Site 1 • Detention provided in regional facility 0 Regional Facility location ' • No detention required (] Acceptable receiving waters ' Downstream Drainage Basins Immediate lAajor Basin Basin GYPS`f GtZ��K Basin B Basin C ' Basin D TOTAL INDIVIDUAL BASIN Drainage Basin(s) A B C D ' Onsite Area 1 �' Offsite Area Type of Storage Facility ' Live Storage Volume 51 4 5� Predeveloped Runoff Rate 2 year 0.7 q- 10 year 1.91 Postdeveloped Runoff Rate 100 year 3.71 ' 2 year 0. + 10 year 1.99 Developed Q 100 year 3.70 ' Type of Restriction OKI FI CP Size of Orifice/Restriction Orifice/Restriction No.1 341 No.2 6. 0" No.3 4.G 9. No.4 ' No.S RD-1 I/90 LIVE STORAGE VOLUME REQ'D= 54,363 C.F. LIVE STORAGE VOLUME PROV'D= 54,600 C.F. WATER QUALITY VOLUME REQ'D= 19,602 C.F. WATER QUALITY VOLUME PROV'D= 21,000 C.F. ' 18" OUT FLOW RESTRICTOR 5 TO CB 10 ' TYPE 2-54" 42 57 MH BASE 8 , 4t INSIDEoL I lMENSION N ACCESS RISER o I GALV. STEPS N o C)DER (TYP.) cv ' S J 12" SD INV. 216.50 z o A z 24"0 INSPECTION J o ' PORT -� o 42' w 0 w � QI 0 10' ' I I INV. 221 .00 \ I �L 1 14'± 24" IN FROM CB 11 90'00' THIS IS NOT A STRUCTURAL PLAN. IT IS INTENDED FOR DIMENSIONS AND ELEVATION PURPOSES ONLY. SEE STRUCTURAL PLANS FOR VAULT DESIGN. STRUCTURAL PLAN' MUST BE DESIGNED & STAMPED BY A REGISTERED PROFESSIONAL STRUCTURAL ENGINEER. 'ALL METAL PARTS: CORROSION RESISTANT. STEEL PARTS GALVANIZED & ASPHAL' COATED (TREATMENT 1 OR BETTER). t FRAMES, GRATES & ROUND ' SOLID, LOCKING COVERS MATCH FINAL GRADE MARKED "DRAIN" ' STD. GALV. STL. STEPS ' & LADDER LIFT GATE ROD N O.F. 223.00 • NOTCH WEIR 6 ELEV.= 221 .90 - ' o a � � • w SUPPORT(S) > 90 GA. BOLT OR -' D 2" IN WALL AT a o aX. 3" SPACE, MIN. J' SUPPORT 18" INV. 216.50 WATERTIGHT SHEAR _z GATE ASSY. PER .2 2.50' WATER ' WSDOT/APWA STD. N QUALITY 4. PLAN B-3. 18" RISER PIPE ELEV.= 214.00 STRICTOR PLATE z ELEV.= 213.50 ORIFICE=2-5/8"0 • • A. • t . (SHARP EDGE N SHOP, DRILLED) 6 SEDIMENT STORAG ' STANDARD 54"0 TYPE 2 BASE SECTION ('5-N FLOW RESTRICTOR DETAIL _ SCALE 1"=2' t^ R\W I 234 JUMFERENTIAL L.=1.25' ' Stafford Crest Techmical Information Report #97-8008 DECLARATION OF COVENANT The Declaration of Covenant is required for privately maintained commercial retention/detention facilities only. As the proposed R/D facility will be maintained by the City of Renton, a Declaration of Covenant is not required for this project. 1 GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 ' Stafford Crest Techmical Information Report 497-8008 1 ' SECTION XI Maintenance and Operations Manual GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 tStafford Crest Techmical Information Report #97-8008 ' MAINTENANCE AND OPERATIONS MANUAL The proposed R/D facility will not be privately maintained, and does not have special, non- standard features. Therefore, a maintenance and operations manual is not required. t r GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell,WA 98011 Stafford Crest Techmical Information Report #97-8008 APPENDIX 1 GROUP FOUR, Inc. 16030 Juanita-Woodinville Way NE Bothell, WA 98011 J.17 dD• A k Ar-W& s7AYZ 7 enwfsT.I t£J a uuo7 ----- — — }� �>x 9 , 50.av• \ 1 i SCALE. 1"=100' . 7 I 0�----- --_� nW OF CONCBfMATION�--\ TRAVEL PATH , I ,72 i AREA - i4.54 Ac 1 ' •�, i ------ -------------- -----------------;;z------- 4/ rl sr Ws!S71 7r l 4 f ' r J , / A0.9 1BR 65J' �� - $ EXISTING BASIN MAP CT. CB 15 \ CB 14 STA. 1+58.59; 15.19'LTI STA 1 +60.43 15.19 LT TOP 231.84 TOP 231.92 INV. 228.84 INV. 228.54 I 30' \ \ CB 16(TYPE 1 -L) \ STA. 20+51; 15.19'LT. TOP 235.96 INV. 231.46(12"IN-S) \ \ NE 36th STREET (FOREST AVE. I INV. 231.21(15"IN-E) INV. 231.21 OUT-W \ -� ) 15 ( \ - �EE�HT-j4�OR IMP�VE�N�-- � \ QFFSITE DRAINAGt�sl+es6a' 1610.*J9� SEE 'SHEET 11 1 14 ------------- 14 . o - -a-- W/SOLID LOCKING LID 5' MIN. STA. 2+47.33; 15.19'RT.(STR) -- TOP 235.39 - INV. 227.67(12"IN-N) INV. 229.89(15"IN-S,E) \ \ ROAD INV 226.67(24"OUT-N) 30LF-12"SD 1 \ L\08'49'55.0" 9LF-r24"CMP �� ® 1.00% _ ® 30.00% 00 9 6 ` i_j,1^6.�210 ROCKERY DRAIN %� �u 7 CB 18 TYP 2-48" (TYP.) 1 5 STA. 22+-0 ; 15.19'LT.(GRT),1 .41 LT CB 11 TY"PE 2-48" ® � CB 20 TYPE 2-48" TOP 248.8 5 c -5p STA. 23+42- 15.19'LT.(GRT)14.41'LT(STR) STA. 18+90; 15.19'LT.(GRT),14.41' _T(STR) INV. 244. (12"IN-�) TOP 251.94 TOP 231.05 35th S T INV. 240. 5(12"IN-E) INV 247.44(12"IN-W INV. 226.55(12"IN-S) 30LF-12"SD - 6 F�15" _- - - -r -,INV. 239 90(15"OUT-W) INV. 243.30(12"IN-S) INV. 221.20(24"IN-E) @ 2,00/0 95LF,24"CP ® 5.76% 2 00% - - / INV. 243.30(12"OUT ) INV. 221.20(24"OUT-N) 152LFti15 CP ® 5.72� T 1 1 1 � CB 21 , STA. 23+42; 15.19 RT. 1 3-TYPE III BARICADES % `-31 12"SD 1 2CA� 2� ti,�0 TOP 251.94 INV 248.04 34 l CB 1 , CB 22 TYPE 2-48 W Ti RU CURB IN ET ° 'A p W/SOLID LOCKING LID STA. 20+51; 15.3 'RT. 30LF-12"SD �� STA. 24+92.93; 14.67'LT. 1 10 TOP 235.96 1 2 13 200% \ �� TOP 253.60 CB 12 . _232.08 \ INV. 249.10(12"IN-S,W) CB 24 STA 18+90; 15.19'RT, CB 19 IN 245.60(12"IN-E) STA. 5 1 .01; 20.6977. TOP 231.05 r� 7 STA. ?2+0 ; 15.19 RT. ® 2.00% �` / �� INV. 245.60(12"OUT-N) TOP 249.35 INV. 227.15 35 TOP 248.81 19 �� , . \ INV. 246.14 � INV. 244.91 ` � CURB RAMP PER CITY - OF R N S RENT ON T . PLAN 0 E ST D. NO. F-03.1 (TYP.) - '�' ��' 20 24 1 STORM CLEANOUT ;E; �� r8J 33 CB 0 3` 17 (TYP.) a ST 0 8;R=35.81 �' / / 42LF-12"CP CB 25 ;n TO 246.46 15 21 ® ® 0.50% C T25 CURB INLET CB 29 TYPE 1 -L Z 241.96 31 � � ° STA. 4+91.33; 15.19'RT. J CB 32 30LF-12"SD U, �6 / STA. 51.01;2G.87'RT. 49.35 TOP 245.15 STA. +50; 191T. ® 2.00� �� @) \ NV.OP 246.35 INV. 240.65(12"IN-S,E) -7 N 30 TOP 254.35 _ \ INV. 240.40(15"OUT-N) IF-12 lT _ 1 249.85 1.98% 3 23 16 CB 26 24+92.93; 15.19 RT. `' STA. 25+70.12; 15.19 LT TO 253.60 TOP 256.33 2 MON & CASE r' INV. 49.70 O 25 74 \ �� INV. 251.83 17 (TYP.) JS ROAD Z �� 9�c--126-06'38.0" -J 31LF-12"S �56< -jlr 29 32 1 7 ,p R=19II�99L- - 54 @ 2.00% ,/ < L=420.377' 7 i W/THRU CUR INLET BYPASS STA. n,/8;R= 5.63' O\ 2 28 23 �, , • TOP 246.59 T 1 r .1 INV. 242.58 C CB 33 STA. 0 15.19 LT. \ �\ 6"PVC DOWNSPOUT � 53 PR 267.23 19 26 i TIGHTLINE ® S=1.00 a i AK NV. 26 f MIN. (TYP.) 40 STA. 43+00; 15.1 RT. �.73 \ TOP 267.23 -, / ' @ 2.002"SID -� 71 o = 121 CB 35(TYPE 2-48") 20 1 _ 11 W/SOLID LOCKING LID r' 00 L = 25 STA. 8+11.33; 15.19'RT.(STR) 41 W `t _ Z6 TOP 263.43 Z ® 33 INV. 258.33(12"IN-E) a INV. 256.10 " CB 27 ( ) � y 12IN-W,S I 70 STA. 27+7M 5.19 T. INV. 256.10(12"OUT-N) �' S1 �, TOP 270.52 56 - INV. 266.02 42 ®2 00% S r.- so 34 � �, o � z 69 CB ' STA. 60+15; 15.19'LT 34th T.37 57 i J TA. 27+70; 15.19 TR TR TOP 259.73 �30LF 12"SD INV. 256.58 - 2.00 B i TOP 270.52 ' 5LF,12"CP ® 0.50% rn y ; � INV. 266.62 24 23 - i r� 30LF 12"CP ® 0.50% cs496 59 S8 68 / ® STA. 8+11. ; 15.19 IT. A TOP 263.43 / 47, I V. 258.93 r y 38 3OLF 12"SD _ CB 38 /' t 36 @2. 0% i STA. 60+15; 15.19'RT. rn 1 42 i 67 --- - - _ 2i TOP 259.73 � _-_ .- INV. 256.73 CURB RAMP PER CITY 44 OF RENTON STD. PLAN - r - NO. F-03.1 (TYP.) F 12"CP 104LF-1 ' SD 4.13� -� -- CB 39 ------ 0.56% NE rd '�T. I 41 MON & ,ASE 2 y ST'A.. 9+60.82; 15.19'RT. ---- , - - - - - (TYP.) - 17 - TOP 271.50 3� 48 61 0 62 63 64 66 _- - - - - -- INV.- 266.60 45 60 40 - - - - - - - - - N88'51'12.6"W _ S.E. 91ST ST. (BLANCHE AVE.) (TO BE VACATED) 6"PVC DOWNSPOUT , 47 TIGHTLINE @ S=1.00 0 �� / r \CB 42 MIN. (TYP.) I ` STA. 33+00; 15.19'RT. ' I TOP 275.75 INV. 271.85 CB 41 1 STORM CLEANOUT ROCKERY DRAIN STA. 33+00-,15.19'LT. 17 (TYP.) i (TYP.) TOP 275.75 / INV. 271 .25 1 3-TYPE III BARICADES 18 CB 40 W/THRU CURB INLET STA. 34+04.06,. 15.37'LT. TOP 269.95 INV. 266.95 a STAFFORD CREST GROUP FOUR, Inc. NO. _ REVISION DATE By DEVELOPED BASIN MAP 16030 J"NITA-WOODINVILLE WAY NE BOTHELL,WASHINGTON 98011 p (425)775-4581 * (206)362-4244 * FAX(206)362-3819 o SURVEYING ENGINEERING PLANNING MANAGEMENT 0 DRAWN BY: CHECKED -BY: APPROVED BY: KING COUNTY WASHINGTON DATE: DATE: DATE: