HomeMy WebLinkAboutSWP272247(1) TECHNICAL INFORMATION REPORT
RENfTON PLACE
' CITY OF RENTON, WASHINGTON
' GROUP FOUR JOB #95-8005
GROUP FOUR, Inc.
16030 Juanita-Woodinville Way NE
t Bothell, WA 98011
FAX(206)362-3819
(206) 775-4581 • (206)362-4244
TECHNICAL INFORI VIA TION REPORT
ItEWON PLACE
CITY OF RENTON, WASHINGTON
' 4.2-16'
' µ �N0. p
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31784
S�NAL4,G
tExPtaES 03/08/98
' April 2, 1996
Prepared For: Prepared By:
Bob Tozer GROUP FOUR, Inc.
PO Box 53312 16030 Juanita-Woodinville Way NE
Bellevue, WA 98015-3312 Bothell, WA 98011
Phone: (206) 228-9731 (206) 362-4244 9 (206) 775-4581
' Renton Place #95-8005
TIR SECTION I
Project Overview
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
' PROJECT OVERVIEW
' PROJECT: Renton Place
SITE AREA: The site consists of approximately 97,138 square feet(2.23 acres).
' SITE LOCATION: Sec. 19, Twp. 23N, Rge 5E
The site is located at 728 S. 19th Street, between SR 515 and
' Talbot Road S. and between S. 18th Street and S. 19th Street in the
City of Renton, Washington(see Figure 1 - Vicinity Map).
' EXISTING ZONING: Residential - 8 DU/GA(R-8)
' EXISTING LAND USE: The site is currently vegetated with deciduous trees (maple & fruit),
evergreen trees (fir), and other shrubs and grass. A wood frame
house and two (2) wood frame accessory structures currently
' occupy the site. It is proposed that the existing residence remain
upon development.
PROPOSED LAND USE: It is proposed that the site be developed with 11 additional single-
family residences with accompanying roadway and utilities.
' SOILS: Based on inspection of Sheet No. 11 of the US Department of
Agriculture 1973 Soil Survey of King County Area, Washington,
the soil on-site consists of Beausite gravelly sandy loam, 6 to 15
' percent slopes. Permeability is moderately rapid, available water
capacity is low, runoff is medium, and the hazard of erosion is
moderate. Beausite gravelly sandy loam belongs to Hydrologic Soil
Group "C". Refer to Figure 4 - Soils Map.
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
SENT By:GROUP FOUR, INC. 6-25-96 9:29AM 2063623819-+ 206 235 2541 ;# 1
GROUP FOUR, INC. or
►vrON FAX TRANSMITTAL
16030 Juanita-Woodinville Way NE -
Bothell, WA 98011 JUN 2 5 1996 DATE: 6-25-98
FAX (206) 362-3819
(208) 775-4581 - (206) 382.4244 �''r��a t.> �r TIME: 9.30 PM
JOB NO: 95-8006
PLEASE DELIVER THE FOLLOWING PAGES TO:
NAME/FIRM: ARNETA HENINGERICITY OF RENTON
FAX NUMBER: 235-2641
TOTAL NUMBER OF PAGES (INCLUDING TRANSMITTAL PAGE): 2
IF YOU DO NOT RECEIVE ALL OF THE PAGES, PLEASE CALL 362.4244 or 775-4581
MEMO
PLEASE FIND ATTACHED A PROPOSED SKETCH FOR A DETENTION TANK
ALTERNATIVE TO THE DETENTION VAULT. BASED ON CONVERSATIONS WITH BOB
TOZER, IT WOULD APPEAR THAT THIS LOCATION WILL PROVIDE A MINIMUM 10 FEET
OF SEPARATION BETWEEN BOTH THE 12 AND 24 INCH WATER LINES, AND WILL
PROVIDE THE SAME DETENTION VOLUME AS THE ORIGINAL VAULT.
THANKSI
FROM: CARMEN VANIER
I
i
W:\WINDATA\04YROMS-8005\FAX62596.DOC
SENT BY:GROUP FOUR, INC. 6-25-96 ; 9:30AM 2063523819 206 235 2541 ;# 2
1E. 134.11 - 12" -
CONNECT TO EXIST. CB
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CB 1 TYPE 244
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SENT BY:GROUP FOUR, INC. 5-13-96 ; 2:09PM 2063623919 206 235 2541 ;# 1
GROUP FOUR, INC. FAX TRANSMITTAL
15030 Juanita-Woodlnvllle Way NE
Bothell, WA 98011 C7Y OF RENTON DATE: 5-16-96
FAX (206) 382-3819 PirCEIVED
(206) 775-4581 - (206) 362-4244 MAY 14 1996 TIME: 2:16 PM
JOB NO: 96-8005
PLEASE DELIVER THE FOLLOWING PAGES TO' `'��V"VG DIVISION
NAME/FIRM: ARNETA HENNINGER
CITY OF RENTON
PLANNING/BUILDING/PUBLIC WORKS DEPARTMENT
FAX NUMBER: (206) 236-2641
TOTAL NUMBER OF PAGES (INCLUDING TRANSMITTAL PAGE): 5
IF YOU DO NOT RECEIVE ALL OF THE PAGES, PLEASE CALL 382-4244
MEMO
PLEASE FIND ATTACHED THE REVISED PIPE SIZING CALCULATIONS FOR RENTON
PLACE BASED ON THE REVISED STORM DESIGN.
NOTE THAT THE VELOCITY OF THE PIPE IN QUESTION (CB#2 TO VAULT) IS 11.03 FPS
(BASED ON THE 100-YEAR DESIGN FLOW) AND 12.18 FPS (FLOWING FULL).
A FINAL, REVISED COPY OF THE TIR WILL BE SUPPLIED PRIOR TO' FINAL
ENGINEERING DESIGN.
FROM: Carmen O. Vanier
SENT BY:GROUP FOUR, INC. 5-13-96 ; 2:09PM 2063823819-4 206 235 2541 ;# 2
Renton Placc #95.8005
CONVEYANCE SYSTEM ANALYSIS & DESIGN
Pipe System Analysis & Design
Conveyance System A
The computer programs "ciA" and "Waterworks Version 3.1" will be used to perform the
analysis of the proposed pipe system for Conveyance System A
Refer to the attached computer output for the results of the analysis.
GROUP FOUR,INC
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
SENT BY:GROUP FOUR, INC. 5-13-96 ; 2:09PM 2063623819- 206 235 2541 ;# 3
5/13/96 GROUP FOUR, Inc. page 1
RENTON PLACE
095-8005 UNIFORM FLOW ANALYSIS
==:sssa====ss�sssssaa==aQassasssssaQ====assssssss�sf a■sac=o=o=c==caamsasae=asoo
REACH SUMMARY
100YR DESIGN STORM
Network Reach LINE1
REACH <-AREA> <-DIA> LENGTH SLOPE < n > DSGN 0 % PIPE Ndepth depth Vact Vfutt C_Area
ID (Ac) (ft) (ft) ft/ft ------ (cfa) ------ (ft) ------ (fps) (fps)
■■�■■�■■:a■r■r■is¢x�=¢¢ss¢sss■■■ra■■■■■■■■■■■■■■■■rr■■■a■■ssttoaaixxxxxxeS■■■■■■■r■■■■■■■■■■■■■■■
P3 1.00 119.00 0.1073 0.0240 2.13 31.24 0.40 39.94 7.28 8.91 A3
Confluence with Network LINE2
Confluence with Network LINE3
P2 1.00 38.00 0.2000 0.0240 4.39 47.13 0.50 50.41 11.06 12.16 �:
Network Reach LINE2
REACH c-AREA), <-DIA> LENGTH SLOPE < n > DSGN 0 % PIPE Ndepth %Depth vast VfuLl C_Area
ID (Ac) (ft) (ft) ft/ft ------ (cfa) ------ (ft) ------ (fps) (fps)
Sisti■■■■■■■■■■■■■■■r■r■■s■riiL���m�xxCS!■r■■■se■r■r■■■■■■■■■■■■■■rrr:■■■=iia60xxxLCL7r=:■■■■■■a■
PZA 1.00 30.00 0.1133 0.0240 0.93 13.27 0.26 25.52 5.88 9.16 $-E
Network Reach LINE3
REACH <-AREA> <-DIA> LENGTH SLOPE < n > DSGN 0 X PIPE Ndepth mepth Vact Vfu(L C-Area
ID (Ac) (ft) (ft) ft/ft ------ (cfe) ...... (ft) (fps) (fps)
Oss■■■■■■■■■■■■■■■■■r■■ra■•■•■•■iir■sasiiL�¢¢oactxxsLCss7x¢sss■■r■R■■e■■■■■■rr■■rr�i■ai■rss■m�LxC
P25 1.00 36.00 0.0278 0.0240 1.33 38.28 0.45 44.71 3.91 4.53 S-N
SENT BY:GROUP FOUR, INC, 5-13-96 ; 2: 10PM 2063623819 206 235 2541 ;# 4
5/13/96 GROUP. FOUR, Inc. page 1
RENTON PLACE
095-8005 BACKWATER ANALYSIS
REACH SUMMARY
10OYR DESIGN STORM
Hydraulic GradeLine for Reach HGl1
<-FROM-> <--TO--> <FLOVs floss Ent HGL EntLoss ExtLosa Outlet intet AppHeed BndHead JunHead Headutr -eb/mh-
-------- -------- of* -Lose- -ELev-- --Loss- --Loss- --Elev- --Elev- --loss- --Lose- --Loss- --Elev- --Rim--
ssx=a=oaeoceoc■s...■■.■..■.■■■■■■■■..■■■■■.■.■■■..a.am.saaaeooaoea■■■■■■■■■...■■■■■■■..■■..■■■sase000neo=cacaeo
VAULT 143.70
C8##2 VAULT 4.39 1.95 145.65 0.24 0.48 146.38 151.57 0.00 0.00 0.00 151.57 158.00
C803 C802 2.13 12.77 tw & do <de: Inlet CtrL Assured 168.05 0.00 0.00 0.00 168.05 170.77
C892 155.26
INTAKE2A CBM2 0.93 3.40 tw & do <dc: inlet CtrL Assumed 158.55 0.00 0.00 0.00 158.55 159.40
C8#2 155.45
IkTAKE2B C042 1.33 1.00 tw & do <de: Inlet CtrL Assumed 156.23 0.00 0.00 0.00 156.23 137.00
SENT BY:GROUP FOUR INC. 5-13-98 ; 2: 10PM 2063523819i 206 235 25414 5
5/13/96 GROUP FOUR, Inc. page 1
RENTON PLACE
#95-8005
�����.�e3ss!!!sslssvC=====��S3�CL•Lm lrre lslassriC��C������___=�=��C=��=3C�s
REACH SUMMARY
PIPE REACH ID No. P2
From: CB#2 To: VAULT
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 38 . 00 ft s: 0.2000
Up invert 149. 80 ft down invert: 142 . 20
Design Flow 4 . 39 cfs Dsgn Depth: 0. 50 ft
Pipe Capacity 9. cfs
Design Val : 1.06 fp <\1FLV-1T"(
ravel Time: 0. 06 min
Pipe Full Vel 12 . 16 fps
IP p{pf-
PIPE REACH ID No. P2A FP-On CO,0 2 ✓A U LT
From: INTAKE2A To: CB#2
Pipe Diameter: 1. 00 ft n: 0.0240
Pipe Length 30. 00 ft s: 0. 1133
Up invert 158 . 40 ft down invert: 155. 00
Collection Area: 0. 91 Ac.
Design Flow 0. 93 cfs Dsgn Depth: 0. 26 ft
Pipe Capacity 7 . 01 cfs
Design Vel 5. 88 fps Travel Time: 0. 09 min
Pipe Full Val 9 . 16 fps
PIPE REACH ID No. P2B
From: INTAKE2B To: CB#2
Pipe Diameter: 1. 00 ft n: 0.0240
Pipe Length 36. 00 ft s: 0. 0278
Up invert 156. 00 ft down invert: 155. 00
Design Flow 1. 33 cfs Dsgn Depth: 0. 45 ft
Pipe Capacity 3 .47 cfs
Design Val 3 . 91 fps Travel Time: 0. 15 min
Pipe Full Val 4 . 53 fps
PIPE REACH ID No. P3
From: CB#3 To: CB#2
Pipe Diameter: 1. 00 ft n: 0.0240
Pipe Length : 119 . 00 ft s: 0. 1073
Up invert 167. 77 ft down invert: 155. 00
Design Flow 2.13 cfs Dsgn Depth: 0.40 ft
Pipe Capacity 6. 82 cfs
Design Val 7 . 28 fps Travel Time: 0. 27 min
Pipe Full Val 8.91 fps
tPage 1 of 2
' King County Building and Land Development Division
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
PART I PROJECT OWNER AND PART2 PROJECTLOCATION
PROJECT ENGINEER AND DESCRIPTION
Project Owner 80k3 TOZER Project Name RENT-ON PL,P`CF,
Address f'D B0X 53312,BE LLEVUE,g8015 Location
Phone (206)22-8- 9M Township 23N
' Project Engineer cAl�r'IEN VAN I Eta Range 5 E
Company GRPU P FCW 9 , 1 NG• Section
(Z06) 362- 4244 Protect Size 2.23 AC
Address Phone Upstream Drainage Basin Size 0.23 AC
PART 3 TYPE OF •
Subdivision 0 DOF/G HPA 0 Shoreline Management
F-1_Short Subdivision E�:] COE 404 E:�] Rockery
E::] Grading 0 DOE Dam Safety Structural Vaults
' E:J Commercial E�:] FEMA Floodplain E::] Other
F-1 Other COE Wetlands 0 HPA
PART 5 WE COMMLNTY MD DRAINAGE BASIN
' Community
Drainage Basin Q`
F-1, River 0 Floodplain
' 0 Stream E:] Wetlands
0 Critical Stream Reach 0 Seeps/Springs
Depressions/Swales High Groundwater Table
' Lake Groundwater Recharge
(� Steep Slopes >51 Other C dAL MIN 5 H f\Z A R D
0 Lakeside/Erosion Hazard
Soil Type Slopes Erosion Potential Erosive Velocities
BEAUS I T-F/ 6- IS % M0DEP,4\Tf" MEDIUM
0 Additional Sheets Attatched
]/90
Page 2 of 2
King County Building and Land Development Division
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
DEVELOPMENT
REFERENCE LIMITATION/SITE CONSTRAINT
Ch.4-Downstream Analysis
O
O
a
o
0
0 &nal Sheets Attatched
PART 9 ESC REOUIREMENTS
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION FOLLOWING CONSTRUCTION
I1 Sedimentation Facilities Stabilize Exposed Surface
IQ Stabilized Construction Entrance ® Remove and Restore Temporary ESC Facilities
C�g Perimeter Runoff Control ® Clean and Remove All Silt and Debris
E::] Clearing and Grading Restrictions Ensure Operation of Permanent Facilities
E:J Cover Practices 0 Flag Limits of NGPES
Construction Sequence 0 Other
E:J Other
PART 10 SURFACE WATER SYSTEM
i Grass Lined Channel Tank Infiltration Method of Analysis
Pipe System Vault 0 Depression SSL1 �f
Open Channel Energy Dissapator 0 Flow Dispersal Compensation/Mitigation
(� Dry Pond E:3 Wetland = Waiver of Eliminated Site Storage
0 Wet Pond 0 Stream 0 Regional Detention
Brief Description of System Operation CONV EY DEVE LDf En STO R rl V✓ATE R R U NO F F IN
NUNDFRC5ROUND PIPE/DIFGHES TO WErVAULr/DET'ENT'IaN VAULF.
Facility Related Site Limitations
Reference Fadlfy Limitation Additional Sheets Attatched
i
i
require
Drainage Easement
(� Cast in Place Vault Other VPUL r Access Easement
[� Retaining Wall 0 Native Growth Protection Easement
E:3 Rockery>4'High E:1 Tract
(� Structural on Steep Slope 0 Other
I or a civil engineer under my supervision have visited the site. Actual
site conditions as observed were incorporated into this worksheet and the
attatchments. To the best of my knowledge the information provided
here is accurate. sq,.ev.,.
3-2q
1190
iRenton Place #95-8005
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405
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Figure 2 - Site Location Map
Not to Scale
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
1
TIR SECTION II
Preliminary Conditions Summary
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
1 Renton Place #95-8005
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' Figure 3-Basin Map
Scale 1" = 1,000'
1 GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
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Renton Place #95-8005
TIR SECTION III
Off-Site Analysis
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
rRenton Place #95-8005
' OFF-SITE ANALYSIS
r A Level 1 Downstream Analysis was previously submitted as a part of the Conceptual Drainage
Report prepared by Group Four, Inc. dated November 29, 1995.
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GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
i
rRenton Place 495-8005
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r TIR SECTION IV
Retention Detention Analysis & Design
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GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
r
Renton Place #95-8005
PRELIMINARY STORAGE VOLUME CALCULATIONS
' PART A: EXISTING SITE HYDROLOGY
Storm water runoff from the site is currently overland to the northeast at an average slope of roughly 9
percent. Approximately 0.23 acres of off-site area currently enters the site from the north half of S. 19th
Street R/W and an existing residence located near the southwest corner of the site.
' I. Basin Input Parameters - Existing Area
A. Total Area to be Analyzed =2.46 acres
1. On-Site=2.23 acres
a. Existing Structures 0.03 acres
b. Shrubs&Grass with Sparse Trees 2.20 acres
2. Off-Site= 0.23 acres
a. Existing Structures 0.04 acres
b. Existing Asphalt(S. 19th St.) 0.08 acres
c. Lawns/Landscaping(good condition) 0.11 acres
iImpervious Area= 0.15 acres
Pervious Area=2.31 acres
B. Soils
1. Beausite gravelly sandy loam
' c. CN Values
1. Shrubs & Grass with Sparse Trees CN= 81
' 2. Structures CN= 98
3. Asphalt CN= 98
4. Lawns/Landscaping (good condition) CN= 86
CN;n,pmo,�= 98
CN pe j.= (0.11)86 + (2.20)81/(2.31) = 81.24
d. Time of Concentration=43.99 minutes
1. 185' Sheet Flow over forest @ 6.32 percent ns=0.40 Tt=28.04 min
2. 115' Sheet Flow over forest @ 11.3 percent ns=0.40 Tt=15.20 min
3. 80' Shallow Flow over forest @ 12.5 percent ks=5 Tt=0.75 min
' f. Precipitation
L P2=2.0"
2. P10=2.9"
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
1
' EX 12' CONC. CULVERT r
TOP=173.59 TOP-140.81
IE.-172.0t
IE.12' RCP. N. 170.77 17 % i i+ r+ > ` I 1E.12" CONC. N. ae
IE.12' RCP. S. 171.19 0 -�` "' %
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146
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96
15.2
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SCALE 1 =40 , \ 1 — — -- c
17,8
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ON-SITE AREA - 1.2S, acr**
0.* uN 1 �150
''' ✓ \ \ \ \ \\ \ \ \ \ \ 1 I \ 1` r EX CB C7
TOP-152.83 Z
i 1E.12" CONC. N. 1
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IE.12' CONC. W. 1
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' Renton Place #95-8005
' PRELIMINARY STORAGE VOLUME CALCULATIONS
' PART B: DEVELOPED SITE HYDROLOGY
It is proposed that developed storm water runoff be conveyed in a system of conveyance swales and
underground storm pipe to the northeast corner of the site. At this point, flow will be conveyed easterly to
a wetvault/detention vault located off-site in the SR 515 right-of-way. It is proposed that the
wetvault/detention vault be located approximately 10' behind the existing concrete sidewalk on the west
' side of SR 515. Maintenance access will be taken from SR 515. It is proposed that a wetvault be used in
place of a biofiltration Swale.
A portion of the rear and side yard of Lot 1, the eastern portion of the 5' R/W dedication, and
' approximately 5' along the rear of Lots 4-8 will bypass the proposed detention facility. The allowable
release rates from the proposed detention facility will be reduced as required to account for flows from this
developed,undetained area.
' It is proposed that the site be developed with 12 DU/2.23 GA, which equals 5.38 DU/GA. This density
corresponds to 49.52%impervious area. Therefore, the total impervious on-site area used in the analysis
will consist of rooftops and paved roadway areas and will equal 1.10 acres (0.4952 x 2.23 acres). By
' inspection,the total pervious on-site area will equal 1.13 acres(2.23 acres- 1.10 acres).
Approximately 0.23 acres of off-site area will be intercepted by the proposed storm system and conveyed
' to the wetvault/detention vault. As a result,this area will be included in the sizing of this facility.
I. Basin Input Parameters - Detained Area
' a. Total Area= 2.32 acres
' 1. On-Site Area= 2.09 acres
a. 12DU/2.23GA=5.38 DU/GA=49.52%imperious=(2.23 ac)(0.4952)=1.10 ac
b. Lawns/Landscaping(good condition)=0.99
2. Off-Site Area= 0.23 acres
a. Existing Structures 0.04 acres
' b. Existing Asphalt(S. 19th St.) 0.08 acres
c. Lawns/Landscaping(good condition) 0.11 acres
' Impervious Area= 1.22 acres
Pervious Area= 1.10 acres
' b. Soils
1. Beausite gravelly sandy loam
' c. CN Values
1. Impervious CN= 98
2. Lawns/Landscaping CN= 86
CN impervious = 98 CN pen,;.,,,= 86
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
' Renton Place #95-8005
t PRELIMINARY STORAGE VOLUME CALCULATIONS
' PART B: DEVELOPED SITE HYDROLOGY
I. Basin Input Parameters - Detained Area (con't)
' d. Time of Concentration= 5.00 min
1. Assume a practical minimum time of concentration of 5.0 minutes for this relatively
' small,heavily developed property.
f. Precipitation
' L P2 = 2.0"
2. PIo=2.9"
' H. Basin Input Parameters - Bypass Area
a. Total Area= 0.14 acres
1. On-Site Area= 0.14 acres
' a. Lawns/Landscaping (good condition) 0.14 acres
(5'of ex. water easement,portion of Lot 1,eastern 5'R/W dedication)
' Impervious Area= 0 acres
Pervious Area= 0.14 acres
' b. Soils
1. Beausite gravelly sandy loam
' c. CN Values
1. Lawns/Landscaping CN= 86
' CN impervious= 98
CN pervious= 86
' d. Time of Concentration= 5.00 min
1. Assume a practical minimum time of concentration of 5.0 minutes for this relatively
small, heavily developed property.
' f. Precipitation
I. PZ=2.0"
' 2. P,o =2.9"
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
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GROUP FOUR,Inc.Renton Place 16030 JUANITA-ROODINVIUX WAY NE
DEVELOPED BASIN MAP BOTHEIL IIASHINGTON 98011
I (206)775-4581 • (206)362-4244 • PAX(206)362-3819
J. Clty of Renton WASHINGTON SURVEYING ENGINEERING PLUVNING MANAGEMENT
' Renton Place #95-8005
' PRELIMINARY STORAGE VOLUME CALCULATIONS
' PART C: HYDROLOGIC ANALYSIS
As required by the Renton Storm and Surface Water Drainage Ordinance (Chapter 22), the drainage
' analysis will comply with the Core and Special Requirements contained in Section 1.2 and 1.3 of Chapter
1, the hydrologic analysis methods contained in Chapter 3, the hydraulic analysis and design criteria in
Chapter 4, and the erosion/sedimentation control plan and practices contained in Chapter 5 of the current
(1990) King County Surface Water Design Manual (KCSWDM), except where amended or appended by
' the Department. The Santa Barbara Urban Hydrograph Methodology with User 1 Rainfall Distribution
and 24-hour design storm durations will be used in the analysis. The computer program "WaterWorks
Version 3.1"will be used to develop and manipulate hydrographs.
' The proposed detention pond will be designed using the following performance requirements:
• Release the 2-year/24-hour pre-developed peak rate of runoff during the 2-year/24-hour
' developed design storm.
• Release the 10-year/24-hour pre-developed peak rate of runoff during the 10-year/24-hour
' developed design storm
PART D: SUPPORTING CALCULATIONS
' Attached is the Hydrograph Methodology, which provides an outline of the steps used in the level pool
routing. The attached Hydrograph Methodology contains computer generated calculations used to
determine the size of the proposed detention vault. Included are applicable basin summary information,
hydrographs, a stage/storage and stage/discharge table,and a level pool table summary.
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
tRenton Place #95-8005
' HYDROGRAPH METHODOLOGY
STEP 1. Generate hydrographs for the 2- and 10-year/24-hour design storms, existing
site conditions.
' MOVE Basin 2EX to Hydrograph#1
Peak Rate of Runoff= 0.181 cfs
' Volume of Runoff= 0.141 ac-ft
Time to Peak= 8.17 hrs
' MOVE Basin IOEX to Hydrograph 94
Peak Rate of Runoff= 0.432 cfs
' Volume of Runoff= 0.274 ac-ft
Time to Peak = 8.17 hrs
1
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' 3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
' #95-8005
---------------------------------------------------------------------
BASIN SUMMARY
BASIN ID: 10EX NAME: 10yr:Existing Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 .46 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
' PRECIPITATION. . . . : 2 .90 inches AREA. . : 2 . 31 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81. 24
TIME OF CONC. . . . . . 43 . 99 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 15 Acres
CN. . . 98 . 00
' TcReach - Sheet L: 185. 00 ns: 0.4000 p2yr: 2 . 00 s: 0. 0632
TcReach - Sheet L: 115. 00 ns: 0.4000 2yr: 2 . 00 s: 0. 1130
TcReach - Shallow L: 80. 00 ks. 5. 00 s:�.y250
PEAK RATE: 0.43 cfs VOL: 0. 27 Ac-ft TIME: 490 min
BASIN ID: 2EX NAME: 2yr:Existing Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 46 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 00 inches AREA. . : 2 . 31 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81. 24
TIME OF CONC. . . . . : 43 . 99 min IMPERVIOUS AREA
' ABSTRACTION COEFF: 0. 20 AREA. . : 0. 15 Acres
CN. . . . : 98. 00
TcReach - Sheet L: 185. 00 ns: 0.4000 p2yr: 2 . 00 s: 0. 0632
TcReach - Sheet L: 115. 00 ns: 0. 4000 2yr: 2 . 00 s: 0. 1130
TcReach - Shallow L: 80. 00 ks: 5. 00 s:�. 250
' PEAK RATE: 0. 18 cfs VOL: 0. 14 Ac-ft TIME: 490 min
' Renton Place #95-8005
' HYDROGRAPH METHODOLOGY
' STEP 2. Generate hydrographs for the 2- and 10-year/24-hour design storms for the
on-site area to be detained, developed site conditions.
' MOVE Basin 2DET to Hydrograph#2
' Peak Rate of Runoff= 0.833 cfs
Volume of Runoff= 0.258 ac-ft
Time to Peak= 7.83 hrs
MOVE Basin IODET to Hydrograph#5
Peak Rate of Runoff= 1.370 cfs
Volume of Runoff= 0.416 ac-ft
Time to Peak= 7.83 hrs
t
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
1 Bothell,WA 98011
' 3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
#95-8005
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BASIN SUMMARY
BASIN ID: 10DET NAME: 10yr:Detained Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 32 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
' PRECIPITATION. . . . : 2 .90 inches AREA. . : 1. 10 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 1. 22 Acres
CN. . 98 . 00
' PEAK RATE: 1. 37 cfs VOL: 0.42 Ac-ft TIME: 470 min
BASIN ID: 2DET NAME: 2yr:Detained Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 32 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 00 inches AREA. . : 1. 10 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
' ABSTRACTION COEFF: 0. 20 AREA. . : 1. 22 Acres
CN. . . . : 98 . 00
PEAK RATE: 0. 83 cfs VOL: 0.26 Ac-ft TIME: 470 min
1
rRenton Place #95-8005
r HYDROGRAPH METHODOLOGY
STEP 3. Generate hydrographs for the 2- and 10-year/24-hour design storms for the
on-site bypass area, developed site conditions.
rMOVE Basin 2BY to Hydrograph#3
r Peak Rate of Runoff= 0.028 cfs
Volume of Runoff= 0.010 ac-ft
Time to Peak= 8.00 hrs
rMOVE Basin 1 OBY to Hydrograph 96
' Peak Rate of Runoff= 0.058 cfs
Volume of Runoff= 0.018 ac-ft
Time to Peak= 7.83 hrs
r
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1
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rGROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
' #95-8005
- - - -------------------------------------------------
BASIN SUMMARY
BASIN ID: 10BY NAME: 10yr:Bypass Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0. 14 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
' PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0. 14 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . 98 . 00
' PEAK RATE: 0. 06 cfs VOL: 0. 02 Ac-ft TIME: 470 min
BASIN ID: 2BY NAME: 2yr:Bypass Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0. 14 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0. 14 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
' ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . . . : 98 . 00
PEAK RATE: 0. 03 cfs VOL: 0. 01 Ac-ft TIME: 480 min
' Renton Place #95-8005
' HYDROGRAPH METHODOLOGY
' STEP 4: Perform the level pool routing. Note that the allowable release rates have
been adjusted to account for undetained, developed flows from the bypass
area.
Use Stage/Storage Table 1 & Stage/Discharge Table 1.
2YR STORM: Developed Inflow Hydrograph#2
Peak Inflow=0.833 cfs
Controlled Outflow Hydrograph#10
Peak Outflow= 0.173 cfs
Peak Stage= 141.27'
Required Volume =2,670.21 cf
1 OYR STORM: Developed Inflow Hydrograph#5
Peak Inflow= 1.370 cfs
Controlled Outflow Hydrograph#11
Peak Outflow= 0.413 cfs
Peak Stage= 143.18'
Required Volume=4,081.53 cf
' The required volume will result in a vault approximately 20' wide x 36.8' long x 5.55' deep.
However, per Section 1.2.3 of the King County Surface Water Design Manual, a 30% factor of
safety must be applied to the required volume without increasing the total depth of storage.
Therefore, a total storm water storage volume of 5,306 CF (1.30 x 4,081.53 CF) is required for
detention. It is proposed that the vault length be increased to (1.30)36.8' = 47.84' = 48 lineal
feet.
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' 3/28/96 GROUP FOUR, Inc. page 5
' RENTON PLACE
#95-8005
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LEVEL POOL TABLE SUMMARY
MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE
<-
-------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf)
-----------------------------------------------------------------------------
2YR STORM .................... 0.17 0.83 1 1 141.27 10 2670.21 cf
10YR STORM ................... 0.41 1.37 1 1 143.18 11 4081.53 cf
' 3/28/96 GROUP FOUR, Inc. page 3
RENTON-PLACE#95-80
95-8005
STAGE STORAGE TABLE
' RECTANGULAR VAULT ID No. 1
Description: Conce tual Detention Vault
Length: 36. 90 f Width: 20. 00 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-
137.65 0.0000 0.0000 139.10 1070 0.0246 140.60 2177 0.0500 142.10 3284 0.0754
137.70 36.900 0.0008 139.20 1144 0.0263 140.70 2251 0.0517 142.20 3358 0.0771
137.80 110.70 0.0025 139.30 1218 0.0280 140.80 2325 0.0534 142.30 3432 0.0788
' 137.90 184.50 0.0042 139.40 1292 0.0296 140.90 2399 0.0551 142.40 3506 0.0805
138.00 258.30 0.0059 139.50 1365 0.0313 141.00 2472 0.0568 142.50 3579 0.0822
138.10 332.10 0.0076 139.60 1439 0.0330 141.10 2546 0.0585 142.60 3653 0.0839
138.20 405.90 0.0093 139.70 1513 0.0347 141.20 2620 0.0601 142.70 3727 0.0856
138.30 479.70 0.0110 139.80 1587 0.0364 141.30 2694 0.0618 142.80 3801 0.0873
' 138.40 553.50 0.0127 139.90 1661 0.0381 141.40 2768 0.0635 142.90 3875 0.0889
138.50 627.30 0.0144 140.00 1734 0.0398 141.50 2841 0.0652 143.00 3948 0.0906
138.60 701.10 0.0161 140.10 1808 0.0415 141.60 2915 0.0669 143.10 4022 0.0923
138.70 774.90 0.0178 140.20 1882 0.0432 141.70 2989 0.0686 143.20 4096 0.0940
138.80 848.70 0.0195 140.30 1956 0.0449 141.80 3063 0.0703
138.90 922.50 0.0212 140.40 2030 0.0466 141.90 3137 0.0720
139.00 996.30 0.0229 140.50 2103 0.0483 142.00 3210 0.0737
I
' 3/28/96 GROUP FOUR, Inc. page 4
' RENTON PLACE
#95-8005
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STAGE DISCHARGE TABLE
' MULTIPLE ORIFICE ID No. 1
Description:
Outlet Elev: 137. 65
Elev: 135. 65 ft Orifice Diameter: 1. 8311 in.
Elev: 141. 35 ft Orifice 2 Diameter: 2 . 3262 in.
STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---I STAGE <--DISCHARGE--->
' (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- -------
---------------
-- ------- --------------------
137.65 0.0000 139.10 0.1096 140.60 0.1563 142.10 0.3191
137.70 0.0203 139.20 0.1133 140.70 0.1589 142.20 0.3295
' 137.80 0.0352 139.30 0.1169 140.80 0.1615 142.30 0.3393
137.90 0.0455 139.40 0.1204 140.90 0.1640 142.40 0.3488
138.00 0.0538 139.50 0.1238 141.00 0.1665 142.50 0.3578
138.10 0.0610 139.60 0.1271 141.10 0.1690 142.60 0.3666
138.20 0.0675 139.70 0.1303 141.20 0.1714 142.70 0.3751
' 138.30 0.0734 139.80 0.1334 141.30 0.1738 142.80 0.3833
138.40 0.0788 139.90 0.1365 141.40 0.2090 142.90 0.3913
138.50 0.0839 140.00 0.1395 141.50 0.2354 143.00 0.3991
138.60 0.0887 140.10 0.1424 141.60 0.2542 143.10 0.4067
' 138.70 0.0932 140.20 0.1453 141.70 0.2700 143.20 0.4141
138.80 0.0976 140.30 0.1481 141.80 0.2839
138.90 0.1017 140.40 0.1509 141.90 0.2965
139.00 0.1057 140.50 0.1536 142.00 0.3081
1
1
' Renton Place #95-8005
' HYDROGRAPH METHODOLOGY
' STEP 5: Calculate the post-developed peak rate of runoff, which is a combination of
the controlled outflow hydrographs and the bypass area hydrographs.
' Post-Developed Peak Rate of Runoff=Bypass+ Controlled Outflow
2yr Post-Developed Peak Rate of Runoff.
ADD Hydrograph#10 +Hydrograph#3 =Hydrograph#13
P
' Peak Rate of Runoff= 0.181 cfs
Volume of Runoff= 0.268 ac-ft
Time to Peak= 10.67 hrs
10yr Post-Developed Peak Rate of Runoff:
' ADD Hydrograph#11 +Hydrograph#6 =Hydrograph #14
' Peak Rate of Runoff= 0.432 cfs
Volume of Runoff= 0.434 ac-ft
Time to Peak= 8.67 hrs
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' o
LEGEND
Hyd No, 3_
Hyd No, 10
Hyd No. 13___
t
w
u
c
~••ti
' 3 6 9 12 15 18 21 24 27 30
Time in Hours
Hyd No. : 3
Rate: 0. 03 cfs Time: 8. 00 hr
Vol 0. 01 Ac-ft Int: 10. 00 min
Hyd No. : 10
Rate: 0. 17 cfs Time: 11. 00 hr
Vol 0. 26 Ac-ft Int: 10. 00 min
Hyd No. : 13
Rate: 0. 18 cfs Time: 10. 67 hr
Vol 0. 27 Ac-ft Int: 10. 00 min
r o
•� LEGEND
rHyd No, 6
Hyd No. 11
Hyd No, 14.__
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' 6 12 18 24 30 36
Time in Hours
Hyd No. • 6
r Rate: 0. 06 cfs Time: 7.83 hr
Vol 0. 02 Ac-ft Int: 10. 00 min
Hyd No. • 11
Rate: 0.41 cfs Time: 8 . 83 hr
r Vol 0.42 Ac-ft Int: 10. 00 min
Hyd No. : 14
Rate: 0.43 cfs Time: 8 . 67 hr
Vol 0.43 Ac-ft Int: 10. 00 min
1
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Renton Place #95-8005
HYDROGRAPH METHODOLOGY
' STEP 6: Compare the pre-developed peak rate of runoff (calculated in Step 1) with
the post-developed peak rate of runoff (calculated in Step 5) to ensure that
the performance requirements are met.
2YR STORM: Pre-Developed Peak Rate of Runoff= 0.181 cfs
(Hydrograph#1)
' Post-Developed Peak Rate of Runoff=0.181 cfs
' (Hydrograph 913)
10YR STORM: Pre-Developed Peak Rate of Runoff= 0.432 cfs
' (Hydrograph#4)
Post-Developed Peak Rate of Runoff= 0.432 cfs
' (Hydrograph #14)
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
3/28/96 GROUP FOUR, Inc. page 2
' RENTON PLACE
#95-8005
---------------------------------------------------------------------
HYDROGRAPH SUMMARY
1
PEAK TIME VOLUME
' HYD RUNOFF OF OF Contrib
NUM RATE PEAK HYDRO Area
cfs min. cf\AcFt Acres
1 0. 181 490 6123 cf 2.46
' 2 0. 833 470 11248 cf 2 . 32
3 0. 028 480 431 cf 0. 14
4 0. 432 490 11953 cf 2 .46
5 1. 370 470 18116 cf 2 . 32
6 0. 058 470 801 cf 0. 14
10 0. 173 660 11248 cf 2 . 32
11 0.413 530 18116 cf 2 . 32
13 0. 181 640 11679 cf 2.46
14 0.432 520 18918 cf 2.46
t
r
Renton Place #95-8005
100-YR OVERFLOW ANALYSIS
A system to control potential overflow must be provided as part of the proposed detention facility
in the event of control structure failure or for storm events exceeding design. The overflow
system will consist of the 12 inch control structure riser. This system will be designed to provide
controlled discharge of the 100-year/24-hour developed design storm directly to the downstream
conveyance system. The maximum allowable head above the top of the riser will be set at 6
inches, which is equal to the minimum inside top of the detention vault (elevation 143.70'). It will
be assumed that the orifices are plugged, and the riser is the only means of discharge. It will also
be assumed that the vault is full to the top of the riser (elevation 143.20'). The results of the
analysis are tabulated below.
r
Input Data:
100-yr/24-hr Developed Overflow=Hydrograph #10 = 1.99 cfs (see attached Basin Summary)
Stage/Discharge Table=Riser Discharge ID No. 1 = Overflow Riser
' Top of Riser= 143.20'
Riser Diameter= 12"
Route Hydrograph #10 through the Riser:
Peak Inflow= (Hydrograph #10) = 1.99 cfs
Peak Outflow= (Hydrograph#20) = 1.99 cfs ---
Peak Stage = 143.55' < 143.70' <---- ==OK
' See attached Waterworks Version 3.1 computer output for supporting calculations.
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' 3/29/96 GROUP FOUR, Inc. page 1
RENTON PLACE
#95-8005
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BASIN SUMMARY
BASIN ID: 100OF NAME: 100yr Overflow
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 32 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 3 .90 inches AREA. . : 1. 10 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 1. 22 Acres
CN. . 98 . 00
' PEAK RATE: 1.99 cfs VOL: 0. 60 Ac-ft TIME: 470 min
r
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1 3/29/96 GROUP FOUR, Inc. page 2
RENTON PLACE
#95-8005
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STAGE DISCHARGE TABLE
1 RISER DISCHARGE ID No. 1
Description: Overflow Riser
Riser Diameter (in) : 12 . 00 elev: 143 .20 ft
1 Weir Coefficient. . . : 3 . 782 height: 143 .70 ft
Orif Coefficient. . . : 9 . 739 increm: 0. 10 ft
1 STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE--->
(ft) ---CfS-- -----------(ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- -------
143.20 0.0000 143.30 0.3080 143.50 1.6003 143.70 2.6743
1 143.20 0.0000 143.40 0.8711 143.60 2.3919
1
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' 3/29/96 GROUP FOUR, Inc. page 3
' RENTON PLACE
#95-8005
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LEVEL POOL TABLE SUMMARY
' MATCH INFLOW -STO- -DIS- <-PEAK->
<--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id
-----------------------------------------------------------------------------
100yr Overflow ............... 1.99 1.99 1 1 143.55 20
1
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1 Renton Place #95-8005
1
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TIR SECTION V
Conveyance System Analysis & Design
1
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1 GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
' CONVEYANCE SYSTEM ANALYSIS & DESIGN
' Per Core Requirement#4 of the King County Surface Water Design Manual, all conveyance systems for proposed
projects must be analyzed for existing tributary off-site runoff, and developed on-site runoff from the proposed
project.
1.Conveyance Svstem A(Upstream of Detention Vault)
a. Pipe System
' The pipe system located upstream of the proposed detention vault will be designed to convey and contain
at least the peak runoff rate for the 25-year design storm calculated using the Rational Method as
described in Section 4.3.3. Two methods of hydraulic analysis using Manning's equation will be used in
' the design and analysis of the proposed pipe system. First, the proposed pipe system will be analyzed
using the Uniform Flow Analysis and must be demonstrated to adequately convey the peak rate of runoff
for the 25-year design storm event. Second, the capacity of the proposed pipe system will be checked
using the Backwater Analysis Method, and must be demonstrated to provide a minimum of 0.50 feet of
' freeboard between the hydraulic grade line and the top of all structures for the 25-year peak rate of runoff.
The proposed conveyance system was analyzed for the 100-year design storm (refer to attatched
' supporting calculations). The results of the attached pipe system analysis show that at least 0.50' of
freeboard in provided between the hydraulic grade line and the top of all structures for the 100-year peak
rate of runoff. By inspection, it can be concluded that these criteria will also be met during the 25-year
' design storm.
a. Drainage Ditch System
Drainage ditches will be designed to convey the required design flow, which is the peak runoff rate from
' the 25-year design storm as calculated using the Rational Method as described in Section 4.3.3. Per Core
Requirement #4, drainage ditches must be demonstrated to provide a minimum freeboard to overflow at
design flow of 0.50 feet. Per Section 4.3.7 (see Table 4.3.7A), vegetation lined channels shall have a
' maximum velocity at design flow of 5 fps. Therefore, Manning's Equation will be used to check flow
depth and velocity during the 25-year design storm. In addition, drainage ditches will be demonstrated to
convey the peak runoff rate from the 100-year design storm without overtopping. As a result, Manning's
Equation will also be used to check flow depth during the 100-year design storm.
The results of the attached drainage ditch analysis show that a minimum of 0.50' of freeboard to overflow
is provided in all cases and that no overtopping occurs during the 100-year design storm. In addition,
' rock-lined channels have been used when velocities at design flow have been determined to be greater
than 5 fps.
2.Convevance System B (Downstream of Detention Vaultl
The capacity of the proposed conveyance system located downstream of the detention vault will be
' checked for capacity using the Backwater Analysis method. This system must be demonstrated to
adequately convey the 100-year/24-hour developed peak rate of runoff during overflow conditions. Note
that all proposed conveyance systems located upstream of the detention vault will be analyzed using the
Rational Method. However, to maintain consistency between methods, all proposed conveyance systems
located downstream of the detention vault will be analyzed using hydrographs as outlined in Section 3.5 of
the King County Surface Water Design Manual.
1 The attached 100-yr overflow analysis shows that the downstream conveyance system has adequate
capacity to convey developed storm water runoff during the 100-year/24-hour design storm.
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
' CONVEYANCE SYSTEM ANALYSIS & DESIGN
Peak Rate of Runoff Analysis
The Rational Method, as outlined in Section 4.3.3 of the King County Surface Water Design
Manual will be used as follows to generate the peak flows used in the analysis of the proposed
conveyance system.
Q = cIA
' Where: Q =peak rate of runoff(cfs)
A=total tributary drainage area(acres)
' c=runoff coefficient
I = peak rainfall intensity(iph)
' I, the peak rainfall intensity, is calculated below for the 25- and 100-year design storms:
' 25-,year Design Storm:
P25 = 3.40"
Tc= 6.30 minutes (assumed minimum) a 25 =2.66
b25 = 0.65
i 25 = (2.66)(6.30) t-0.651= 0.80
125= (3.40")(0.80) = 3.20 iph
100-year Design Storm:
P100 = 3.90"
' Tc= 6.30 minutes (assumed minimum) a too = 2.61
b too = 0.63
i ioo = (2.61)(6.30) (-0.63)= 0.82
I ioo= (3.90")(0.82) = 3.20 iph
The results of the analysis are tabulated below:
IMPERVIOUS PERVIOUS
off-Site On-Site off-Site On-Site 1 (25) Q (25) 1 (100) Q (100)
1 AREA ID. TOTAL c=0.90 c=0.90 c=0.25 c=0.25 Weighted "c" (iph) (cfs) (iph) (cfs)
A4 0.74 0.04 0.70 0.00 0.00 0.90 2.72 1.81 3.2 2.13
' S-N (swale - north) 0.99 0.08 0.18 0.11 0.62 0.42 2.72 1.13 3.2 1.33
' S-E (swale- east) 0.59 0.00 0.22 0.00 0.37 0.49 2.72 0.79 3.2 0.93
TOTAL 2.32 0.12 1.10 0.11 0.99
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
' #95-8005
------------------------------------------------
RATIONAL DRAINAGE AREA SUMMARY
Drainage Area Id: A4
Description. . . . . : Area Tributary to CB#4
<---Description--> SubArea SubC L (ft) Slope -Kr-- (min)
Impervious Area 0.74 0.90
Pervious Area 0.25
Composite "c" Value. . . . . . . . 0.90 Time of Conc (min) . . 6. 30
' Drainage Area Id: S-E Description. . . . . : Area Tributary to East Swale
<---Description--> SubArea SubC L (ft) Slope -Kr-- (min)
Impervious Area 0.22 0.90
Pervious Area 0.37 0. 25
tComposite "c" Value. . . . . . . . 0. 49 Time of Conc (min) . . 6. 30
Drainage Area Id: S-N
Description. . . . . : Area Tributary to North Swale
' <---Description--> SubArea SubC L (ft) Slope -Kr-- (min)
Impervious Area 0. 26 0. 90
Pervious Area 0.73 0. 25
Composite "c" Value. . . . . . . . 0.42 Time of Conc (min) . . 6. 30
Renton Place #95-8005
' CONVEYANCE SYSTEM ANALYSIS & DESIGN
Pipe System Analysis & Design
Conveyance System A
The computer programs "ciA" and "WaterWorks Version 3.1" will be used to perform the
' analysis of the proposed pipe system for Conveyance System A.
Refer to the attached computer output for the results of the analysis.
r
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
#95_8005 _UNIFORM FLOW ANALYSIS________________________
REACH SUNII�IARY
iOOYR DESIGN STORM
Network Reach LINE1
REACH <-DIA> LENGTH SLOPE < n > DSGN Q % PIPE Ndepth %Depth Vact Vfull C_Area
ID (ft) (ft) ft/ft ------ (cfs) ------ (ft) ------ (fps) (fps)
P4 1.00 127.68 0.0953 0.0240 2.13 33.14 0.41 41.26 6.97 8.40
Confluence with Network LINE2
Confluence with Network LINE3
P2 1.00 30.00 0.3000 0.0240 4.39 38.49 0.45 44.85 12.86 14.90
Network Reach LINE2
REACH <-DIA> LENGTH SLOPE < n > DSGN Q % PIPE Ndepth %Depth Vact Vfull C Area
ID (ft) (ft) ft/ft ------- (cfs) ------- (ft) ------- (fps) (fps)
------------------------------------------------------------------- --
P2A 1.00 10.00 0.1560 0.0240 0.93 11.31 0.24 23.55 6.59 10.74 S-E
Network Reach LINE3 -
REACH <-DIA> LENGTH SLOPE < n > DSGN Q % PIPE Ndepth %Depth Vact Vfull C Area
ID (ft) (ft) ft/ft ------ (cfs) ------ (ft) ------ (fps) (fps)
-------------------------------------------------------------------------------------------------
-------------------------------------------------------------------------------------------------
P3A 1.00 10.00 0.0650 0.0240 1.33 25.02 0.35 35.44 5.33 6.93 S-N
P3 1.00 20.36 0.1130 0.0240 1.33 18.98 0.31 30.65 6.50 9.14
3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
1 #95-8005 BACKWATER ANALYSIS
----- -------
REACH SUMMARY
100YR DESIGN STORM
1 Hydraulic Gradeline for Reach HGL1 -
<-FRO?4 > <--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--
VAULT 143.70
CB#2 VAULT 4.39 1.54 145.24 0.24 0.48 145.97 152.92 0.00 0.00 0.00 152.92 157.60
CB#4 CB#2 2.13 12.17 tw & do <dc: Inlet Ctrl Assumed 168.05 0.00 0.00 0.00 168.05 170.77
C1#2 155.84
INTAKE2A CB#2 0.93 1.56 tw & do <dc: Inlet Ctrl Assumed 157.29 0.00 0.00 0.00 157.29 158.16
CB#2 152.92
CB#3 CB#2 1.33 0.10 153.02 0.02 0.04 153.09 153.69 0.04 0.05 0.00 153.69 155.50
1 INTAKE3A CB#3 1.33 6.95 tw & do <dc: Inlet Ctrl Assumed 154.36 0.00 0.00 0.00 154.36 155.15
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RENTON PLACE
#95-8005
---------------------------------------------------------------------
REACH SUMMARY
' PIPE REACH ID No. P2
From: CB#2 To: VAULT
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 30. 00 ft s: 0.3000
Up invert 151.20 ft down invert: 142 . 20
Design Flow 4 . 39 cfs Dsgn Depth: 0.45 ft
Pipe Capacity 11.40 cfs
Design Vel 12 .86 fps Travel Time: 0. 04 min
Pipe Full Vel 14 .90 fps
PIPE REACH ID No. P2A
From: INTAKE2A To: CB#2
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 10. 00 ft s: 0. 1560
Up invert 157. 16 ft down invert: 155. 60
' Design Flow 0. 93 cfs Dsgn Depth: 0. 24 ft
Pipe Capacity 8 . 22 cfs
Design Vel 6. 59 fps Travel Time: 0. 03 min
' Pipe Full Vel 10.74 fps
PIPE REACH ID No. P3
From: CB#3 To: CB#2
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 20. 36 ft s: 0. 1130
Up invert 153 . 50 ft down invert: 151. 20
' Design Flow 1. 33 cfs Dsgn Depth: 0. 31 ft
Pipe Capacity 7 . 00 cfs
Design Vel 6. 50 fps Travel Time: 0. 05 min
Pipe Full Vel 9. 14 fps
PIPE REACH ID No. P3A
From: INTAKE3A To: CB#3
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 10. 00 ft s: 0. 0650
Up invert 154. 15 ft down invert: 153 . 50
' Design Flow 1. 33 cfs Dsgn Depth: 0. 35 ft
Pipe Capacity 5. 31 cfs
Design Vel 5. 33 fps Travel Time: 0. 03 min
Pipe Full Vel 6. 93 fps
1
1 3/28/96 GROUP FOUR, Inc. page 2
1 RENTON PLACE
#95-8005
---------------------------------------------------------------------
REACH SUMMARY
1 PIPE REACH ID No. P4
From: CB#4 To: CB#2
Pipe Diameter: 1. 00 ft n: 0. 0240
1 Pipe Length 127. 68 ft s: 0. 0953
Up invert 167. 77 ft down invert: 155. 60
Design Flow 2 . 13 cfs Dsgn Depth: 0.41 ft
Pipe Capacity 6.43 cfs
Design Vel 6.97 fps Travel Time: 0. 31 min
Pipe Full Vel 8 . 40 fps
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' Renton Place #95-8005
' CONVEYANCE SYSTEM ANALYSIS & DESIGN
Drainage Ditch Analysis & Design
Conveyance System A
The proposed drainage ditches will be analyzed using Manning's Equation as follows:
' Q = 1.49 A R2" S'n
n
' Where: Q = flow rate (cfs)
Bottom Width= 0 (V-ditch cross section)
Side Slopes= 3(H):I(V)
Longitudinal Slope=varies
Manning's "n" = 0.027 (constructed channels, short grass,few weeds)
Manning's"n" = 0.035 (constructed channels, rock-lined, smooth&uniform)
' North Swale:
• Segment 1: Grass-lined, slope varies from 2.74% - 12.12%
Q25= 1.13 cfs
Q100 = 1.33 cfs
Min. Sloe Max. Slope
2.74% 12.12%
' 25-yr Design Storm
Flow Depth (ft) 0.36 0.28
Velocity (fps) 2.84 4.94
100-yr Design Storm
Flow Depth (ft) 0.39 0.29
• Segment 2: Rock-lined, slope varies from 14.04% - 19.05%
' Q25= 1.13 cfs
Qioo = 1.33 cfs
Min. Slope Max. Slope
' 14.04% 19.05%
25-yr Design Storm
Flow Depth (ft) 0.30 0.28
' Velocity (fps) 4.31 4.82
100-yr Design Storm
Flow Depth (ft) 0.31 0.30
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
CONVEYANCE SYSTEM ANALYSIS & DESIGN
Drainage Ditch Analysis & Design
Conveyance System A
East Swale:
' • Segment 1: Grass-lined, slope varies from 3.59% - 12.9%
1 Q25= 0.79 cfs
Qioo = 0.93 cfs
Min. Sloe Max. Slope
' 3.59% 12.90%
25-yr Design Storm
Flow Depth (ft) 0.30 0.24
' Velocity (fps) 2.86 4.63
100-yr Design Storm
' Flow Depth (ft) 0.32 0.25
iGROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
CONVEYANCE SYSTEM ANALYSIS & DESIGN
100-yr Overflow Analysis
' Conveyance System B
The 100-year/24-hour developed peak rate of runoff entering the downstream conveyance system
' from the proposed detention facility during overflow conditions was determined to be 1.99 cfs
(see 100-yr Overflow Analysis, Hydrograph #20). Overflow from the control structure will be
conveyed northerly approximately 52 lineal feet to C13#1, then easterly approximately 21 lineal
' feet to an existing catch basin located in SR 515.
The computer program "WaterWorks Version 3.1" will be used to perform the analysis of the
' proposed pipe system for Conveyance System B. See attached WaterWorks Version 3.1
computer output for supporting calculations.
r
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
' 3/29/96 GROUP FOUR, Inc. page 4
RENTON PLACE
#95-8005
---------------------------------------------------------------------
REACH SUMMARY
BACKWATER ANALYSIS
' Hydraulic Gradeline for Reach HGL1 100yr/24hr Overflow Analysis
<-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--
,
EXCB 134.59
CB1 EXCB 1.99 1.02 to & do <dc: Inlet Ctrl Assumed 135.42 0.10 0.13 0.00 135.45 146.00
VAULT CB1 1.99 10.62 to & do <dc: Inlet Ctrl Assumed 137.94 0.00 0.00 0.00 137.94 143.70
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' 3/29/96 GROUP FOUR, Inc. page 1
RENTON PLACE
' #95-8005
---------------------------------------------------------------------
REACH SUMMARY
100yr/24hr Overflow Analysis
' PIPE REACH ID No. P1
From: CB1 To: EXCB
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 20.92 ft s: 0. 0488
Up invert 135. 13 ft down invert: 134 . 11
Collection Area: 2 . 32 Ac.
Design Flow 1. 99 cfs Dsgn Depth: 0. 48 ft
Pipe Capacity 4 . 60 cfs
Design Vel 5. 34 fps Travel Time: 0. 07 min
Pipe Full Vel 6. 01 fps
' PIPE REACH ID No. PV
From: VAULT To: CB1
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Length 51. 06 ft s: 0. 0494
Up invert 137 . 65 ft down invert: 135. 13
' Collection Area: 2 . 32 Ac.
Design Flow 1. 99 cfs Dsgn Depth: 0. 48 ft
Pipe Capacity 4 . 62 cfs
Design Vel 5. 37 fps Travel Time: 0. 16 min
' Pipe Full Vel 6. 04 fps
rRenton Place #95-8005
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TIR SECTION VI
Special Reports & Studies
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GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
Renton Place ##95-8005
' SPECIAL REPORTS & STUDIES
The following is a list of the special reports & studies prepared in support of the proposed
development:
' 0 "Geotechnical Report" prepared by Terra Associates, Inc., dated September
16, 1995 (Project No. T-2970)
• "Coal Mine Hazard Evaluation' prepared by Terra Associates, Inc., dated
February 20, 1996 (Project No. T-2970-1)
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
TIR SECTION VII
Basin & Community Plan Areas
' N/A
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
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Other Permits
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' N/A
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GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
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TIR SECTION IX
Erosion/Sedimentation Control Design
1
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iGROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
' EROSION/SEDIMENTATION CONTROL DESIGN
' Filter fabric fence can be used to help reduce the amount of sediment transported beyond the
disturbed areas of the construction site. Filter fabric fence is proposed along the north and east
property lines to provide temporary erosion and sedimentation control. Per the King County
Surface Water Design Manual Section 5.4.3, at the boundary of the site, perimeter protection may
be used as the sole form of treatment when the flow path meets the following criteria:
' Average Slope Flow Path Length
1.5H:1V or less (66.67%) 100,
' 2H:1 V or less (50%) 115'
4H:1 V or less (25%) 150'
6H:1V or less (16.67%) 200'
1 OH:1V or less (10%) 250'
The average slope across the site is approximately 8.63%.
iAverage Slope = (High Elev. - Low Elev.)
(Diagonal Distance from SW corner to NE corner)
Average Slope = (190' - 154')/(417') = 8.63%
From the above table, the maximum flow path length for average slopes of 10% or less is 250
feet. The maximum flow path length proposed is greater than 250', however, the average flow
path length is less than 250 lineal feet. In addition, the area tributary to the proposed filter farbric
fence is relatively small. The total site area consists of 2.23 acres. Roughly one half of the site
drains in each direction (i.e. northerly and easterly), resulting in just over one acre of upstream
area tributary to each section of filter fabric fence. In addition, relatively steep slopes exist
tadjacent to the north and east property lines. As a result, it is desirable to maintain
unconcentrated, overland flow patterns. Therefore, it would appear that the installation of filter
' fabric fence as proposed should be adequate for use as primary treatment of sediment laden water
during construction of the proposed project.
I
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Project Name:
GROUP FOUR,InC. Project No.:
16030 Juanita-Woodinville Way N.E. Date: By:
Bothell, Washington 98011
206 775-4581 Sheet: Page of
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PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT) 2 j
.13 8.00 4864
ENTER [d:][path]filename[.ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
d:\rstraka\junk
FILE ALREADY EXIST; OVERWRITE (Y or N) ?
Y
SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP
c
----------------------------------------------------------------------
ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 2
2.23,76,0,0,43.99
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS, IMPERVIOUS TC(MINUTES)
A CN
2.2 2. .0 .0 44.0
PEAK(HRS) VOL(CU-FT)
12.50 3334
ENTER [d:] [path]filename[.ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
SPECIFY STORM OPTION:
1
S.C.S. TYPE-IA RAINFALL DISTRIBUTION C Wf t-)
ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES)
2,24,2
----------------------------------------------------------------------
******************** S.C.S. TYPE-lA DISTRIBUTION ********************
4-HOUR STORM **** 2.00" TOTAL PRECIP. *********
----------------------------------------------------------------------
ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1
2.23,81,0,0,43.99
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A CN A CN
2.2 2.2 81. .0 .0 44.0
PE T-PEAK(HRS) VOL(CU-FT)
13 8.00 4864
ENTER [d:] [path]filename[.ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
SPECIFY STORM OPTION:
1
S.C.S. TYPE-IA RAINFALL DISTRIBUTION
ENTER: FREQ(YEAR), DURATION(HOUR) , PRECIP(INCHES)
100,24,3.9
----------------------------------------------------------------------
******************** S.C.S. TYPE-lA DISTRIBUTION ********************
********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. *********
----------------------------------------------------------------------
ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1
.85,86,1.10,98,5
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A CN A CN
2.0 .9 86.0 1.1 98.0 5.0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
1.70 7.67 22213
ENTER [d:] [path]filename[.ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
FOR DISTRIBUTION TO:
p Water Utility Building Division
Wastewater Utility Public Works Constr Inspector
Surface Water Utility Fire Prevention
0 Maintenance Services
Transportation Systems
Project: ] �1U7'-�/�J T �L.4T
Location:s 17 �Y L bT
Attached please find copies of
PERMIT BILLS OF SALE
0 RECEIPT COST DATA INVENTORY
0 LETTER OF SPECIAL BILLING EASEMENT(S)
STUB SERVICE AGREEMENT
COPY OF AS-BUILT
PRECON NOTES
PRECON ATTENDEES
DRAINAGE REPORT
FQ MEMO-WATER BREAKDOWN
I MAP WITH NEW MAINS AND VALVES
W* OTHER
�7 d3 40
From:
/ CIOrr
Date: ``r''�`9�
C:TB:PRECON:DISTFRM
1
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CONCEPTUAL DRAINAGE REPORT
1
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RENTON PLACE
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CITY OF RENTON, WASHINGTON
1 GROUP FOUR JOB #95-8005
1
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DEC 11 1995
1 pEVELUphA&N-,PLANNING
ON
pIT(OF SL _r
GROUP FOUR, Inc.
1 16030 Juanita-Woodinville Way NE
Bothell, WA 98011
FAX(206)362-3819
1 (206) 775-4581 • (206)362-4244
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CONCEPT UAL DRAINA GE REPORT
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RENTON PLACE
CITY OF RENTON, WASHINGTON
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31784
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EXPIRES 03/08I
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November 29, 1995
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Prepared For: Prepared By:
' Bob Tozer GROUP FOUR, Inc.
PO Box 53312 16030 Juanita-Woodinville Way NE
Bellevue, WA 98015-3312 Bothell, WA 98011
' Phone: (206) 228-9731 (206) 362-4244 • (206) 775-4581
f
1
TABLE OF CONTENTS
' I. INTRODUCTION
Project Information
Figure I - Vicinity Map
Figure 2 - Basin Map
Figure 3 - Soils Map
' H. CONCEPTUAL DRAINAGE ANALYSIS
Purpose of Analysis
Methodology
Existing Drainage
' Proposed Drainage
Conclusions
III. DOWNSTREAM ANALYSIS
' Downstream Analysis
IV. PRELIMINARY STORAGE VOLUME CALCULATIONS
' Part A: Existing Site Hydrology
Part B: Developed Site Hydrology
Part C: Hydrologic Analysis
Part D: Supporting Calculations
' V. APPENDIX
Existing Basin Map
Developed Basin Map
Renton Place #95-8005
I. INTRODUCTION
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
t
Renton Place #95-8005
PROJECT INFORMATION
' PROJECT: Renton Place
SITE AREA: The site consists of approximately 97,138 square feet (2.23 acres).
SITE LOCATION: Sec. 19, Twp. 23N, Rge 5E
The site is located at 728 S. 19th Street, between SR 515 and
Talbot Road S. and between S. 18th Street and S. 19th Street in the
City of Renton, Washington (see Figure 1 - Vicinity Map).
' EXISTING ZONING: Residential - 8 DU/GA(R-8)
EXISTING LAND USE: The site is currently vegetated with deciduous trees (maple & fruit),
' evergreen trees (fir), and other shrubs and grass. A wood frame
house and two (2) wood frame accessory structures currently
occupy the site. It is proposed that the existing residence remain
upon development.
' PROPOSED LAND USE: It is proposed that the site be developed with 11 additional single-
family residences with accompanying roadway and utilities.
' SOILS: Based on inspection of Sheet No. 11 of the US Department of
Agriculture 1973 Soil Survey of King County Area, Washington,
the soil on-site consists of Beausite gravelly sandy loam, 6 to 15
' percent slopes. Permeability is moderately rapid, available water
capacity is low, runoff is medium, and the hazard of erosion is
moderate. Beausite gravelly sandy loam belongs to Hydrologic Soil
Group "C". Refer to Figure 3 - Soils Map.
t
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
iRenton Place #95-8005
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Not to Scale
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
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},c� �,�;,} ,.�`,•VVVVV�,.'t �. ti�,r�,.E��e�1k'�j�.� �.' �• �" " i 'T � �'�''�y
Nw t.. � r;i � ��w.s � � L•4 a'''`'r�R,.c,,,_ t
4'!
^ i «• -ej k yf1��-b� }:_� ,• � •.ti,�k,3s.�.t-•`3 z;Z2r.�
� { ��� ,�r}� •e � 4 1 :�, •t+6 _<..'�fir.
1 ,fF ,fc a?h����a a� 4X-`"+.R q 1, ,s ���� ..+i ♦ -_;`�r:.. �'�����'T-'!I p.
��r. .:::..{ `c ,� � t3.•:3�t},•.ya.� '< � '� .�.. +'�ie.�s�Fl�,�'Y� �T.r � 4",���J
•;.4
Renton Place #95-8005
II. CONCEPTUAL DRAINAGE ANALYSIS
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
CONCEPTUAL DRAINAGE ANALYSIS
' PURPOSE OF ANALYSIS
This analysis provides hydrologic methodology and calculations which support the conceptual
drainage design of the proposed plat of Renton Place. This analysis also discusses natural
drainage system features, identifies any difficult site parameters and addresses potential impacts
that may result from the proposed development. This analysis corresponds to the current site
plan, and is subject to change upon final engineering design and/or site plan revisions.
METHODOLOGY
As required by the Renton Storm and Surface Water Drainage Ordinance (Chapter 22), the
drainage analysis will comply with the Core and Special Requirements contained in Section 1.2
and 1.3 of Chapter 1, the hydrologic analysis methods contained in Chapter 3, the hydraulic
' analysis and design criteria in Chapter 4, and the erosion/sedimentation control plan and practices
contained in Chapter 5 of the current (1990) King County Surface Water Design Manual
(KCSWDM), except where amended or appended by the Department. The Santa Barbara Urban
Hydrograph Methodology with User 1 Rainfall Distribution and 24-hour design storm durations
will be used in the analysis. The computer program "WaterWorks Version 3.1" will be used to
develop and manipulate hydrographs.
' EXISTING DRAINAGE
Storm water runoff from the site is currently overland to the northeast at an average slope of
roughly 9 percent.
PROPOSED DRAINAGE
It is proposed that developed storm water runoff be conveyed in a system of conveyance swales
and underground storm pipe to the northeast corner of the site. At this point, flow will be
conveyed easterly to a wetvault/detention vault located off-site in the SR 515 right-of-way. It is
' proposed that the wetvault/detention vault be located approximately 10' behind the existing
concrete sidewalk on the west side of SR 515. Maintenance access will be taken from SR 515. It
is proposed that a wetvault be used in place of a biofiltration sff-ale.
A portion of the rear and side and of Lot 1 and the rear of Lots 4-8 which represents the area
P Y ( p s ea
corresponding to the existing 15' water easement) may bypass the proposed detention facility.
The allowable release rates from the proposed detention facility will be reduced as required to
account for flows from this developed, undetained area.
' It is proposed that the site be developed with 12 DU/2.23 GA, which equals 5.38 DU/GA. This
density corresponds to 49.52% impervious area. Therefore, the total impervious area used in the
analysis will consist of rooftops and paved roadway areas and will equal' 1.1_ 0 acres (0.4952 x 2.23 acres). By inspection, the total pervious area will equal 1.13 acres (2.23 acres'- I.10 acres).
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
CONCEPTUAL DRAINAGE ANALYSIS
CONCLUSIONS
The required storm water storage and runoff treatment volumes will be provided as "live" and
"dead" storage, respectively, in a combination wetvault/detention vault. Preliminary storage
volume calculations (see Section IV of this report) indicate that a storm water storage volume of
approximately 4,274 CF +/-will be required for detention. The required volume corresponds to a
vault approximately 20' wide x 36.9' long x 5.8' deep. However, per Section 1.2.3 of the King
County Surface Water Design Manual, a 30% factor of safety must be applied to the required
volume without increasing the total depth of storage. Therefore, a total storm water storage
volume of 5,556 CF (1.30 x 4,274 CF) is required for detention. It is proposed that the vault
length be increased to (1.30)36.9' = 47.97' = 48 lineal feet. The required runoff treatment
volume will be calculated during final engineering design. The location and dimensions of the
proposed detention vault are shown on the Preliminary Drainage Plan.
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
DOWNSTREAM ANALYSIS
' Runoff from the site enters an existing catchbasin on the northeast side of the property. A 12 inch
pipe then conveys flow east 23 feet to a catchbasin located on the west side of Highway 515.
From this catchbasin, runoff from the site enters the storm system of Highway 515. Flow travels
north 170 feet, 200 feet, 250 feet, 120 feet, and 120 feet respectively in a catchbasin/manhole and
12 inch diameter pipe system. At this point, flow is conveyed northeast approximately 225 feet
across Highway 515 to a manhole located on the east side of the road. Flow is piped easterly
' from this structure approximately 40 feet, prior to discharging into a large depression which is fed
by a small stream. Runoff from the depression enters a 36 inch CMP at the southeast corner of
the Highway 515 and S. Puget Drive intersection. This culvert conveys flow north for 175 feet
before entering a catch basin. Flow is then directed northwesterly through another 36 inch CMP
for approximately 312 feet, prior to eventually entering a 42 inch pipe system which continues
northerly under Highway 515.
Through inspection of the downstream system, no erosion, scouring, or signs of flooding were
evident. Therefore, it is concluded that the proposed development will have a minimal impact on
the downstream drainage system(s).
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
t
IV. PRELIMINARY STORAGE VOLUME
CALCULATIONS
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
. 13 8.00 4864 C ��
ENTER [d: ] [path]filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
d:\rstraka\junk
FILE ALREADY EXIST; OVERWRITE (Y or N) ?
y
SPECIFY: C - CONTINUE, N - NEWSTORM, P - PRINT, S - STOP
c
----------------------------------------------------------------------
ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 2
2.23,76,0,0,43.99 f
DATA PRINT-OUT:
AREA(ACRES) PERVIOy-S- IMPERVIOUS TC(MINUTES)
A / CN
2.2 2. .0 .0 44.0
PEAK-Q(CFS) ,,)T-PEAK(HRS) VOL(CU-FT)
.06 12.50 3334
ENTER [d: ] [path]filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
SPECIFY STORM OPTION:
S.C.S. TYPE-lA RAINFALL DISTRIBUTION Wf rI
ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES) 5
2,24,2
----------------------------------------------------------------------
******************** S.C.S. TYPE-lA DISTRIBUTION ********************
2-YEAR 4-HOUR STORM **** 2.00" TOTAL PRECIP. *********
----------------------------------------------------------------------
ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1
2.23,81,0,0,43.99
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A C81
A CN
2.2 2.2 � .0 .0 44.0
PEAK-Q(CF-S)., T-PEAK(HRS) VOL(CU-FT)
.13 8.00 4864
ENTER [d: ] [path]filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
SPECIFY STORM OPTION:
1 a`
S.C.S. TYPE-lA RAINFALL DISTRIBUTION
ENTER: FREQ(YEAR) , DURATION(HOUR) , PRECIP(INCHES)
100,24,3.9
----------------------------------------------------------------------
******************** S.C.S. TYPE-IA DISTRIBUTION ********************
********* 100-YEAR 24-HOUR STORM **** 3.90" TOTAL PRECIP. *********
----------------------------------------------------------------------
ENTER: A(PERV) , CN(PERV) , A(IMPERV) , CN(IMPERV) , TC FOR BASIN NO. 1
.85,86,1.10,98,5
DATA PRINT-OUT:
AREA(ACRES) PERVIOUS IMPERVIOUS TC(MINUTES)
A CN A CN
2.0 .9 86.0 1 . 1 98.0 5.0
PEAK-Q(CFS) T-PEAK(HRS) VOL(CU-FT)
1 .70 7.67 22213
ENTER [d: ] [path]filename[ .ext] FOR STORAGE OF COMPUTED HYDROGRAPH:
Renton Place #95-8005
' PRELIMINARY STORAGE VOLUME CALCULATIONS
' PART A: EXISTING SITE HYDROLOGY
I. Basin Input Parameters - Existing Area
' a. Total Area=2.23 acres
1. Forest, young second growth, brush and shrubs= 2.23 acres
Impervious Area= 0 acres
Pervious Area=2.23 acres
b. Soils
1. Beausite gravelly sandy loam Sa ,L 7-f� ` - 4v�V,3�I C- S°,L
c. CN Values
1. Forest= 81 .`��-
CN unpemous= 98
CNpm0_;_W' -7Co
d. Time of Concentration= 43.99 minutes
1. 185' Sheet Flow over forest @ 6.32 percent ns=0.40 Tt=28.04 min
2. 115' Sheet Flow over forest @ 11.3 percent ns=0.40 Tt=15.20 min
3. 80' Shallow Flow over forest @ 12.5 percent ks=5 Tt=0.75 min
1 U= ks r, z s n,%z5
f. Precipitation
I. PZ=2.0"
' 2. Plo' 2.9" 4A vv"_h
fop 1
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
PRELIMINARY STORAGE VOLUME CALCULATIONS
' PART B: DEVELOPED SITE HYDROLOGY
I. Basin Input Parameters - Detained Area
' a. Total Area= 1.95 acres
1. 12DU/2.23GA=5.38 DU/GA=49.52% impervious=(2.23 ac)(0.4952)=1.10 ac
' 2. Pervious Area=Total Area-Impervious-Bypass=(2.23-1.10-0.28)= 0.85 acres
Impervious Area= 1.10 acres
Pervious Area= 0.85 acres
b. Soils
' 1. Beausite gravelly sandy loam
c. CN Values ,/
' 1. Rooftops = 98
`/2. Paved Roadway= 98
' 3. Lawns/Landscaping= 86
CN ;�,��;o = 98
CN 86
d. Time of Concentration= 5.00 min
1. Assume a practical minimum time of concentration of 5.0 minutes for conceptual
analysis for this relatively,small,heavily developed property.
olG z �J� ,•- G I GL..j Y1 f"+ 51.nu1d J�� ad�v���
f. Precipitation
' L P2 = 2.0"
2. P10= 2.9"
A r.
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
' PRELIMINARY STORAGE VOLUME CALCULATIONS
PART B: DEVELOPED SITE HYDROLOGY
II. Basin Input Parameters - Bypass Area
ta. Total Area= 0.28 acres
1. Lawns/Landscaping= 0.28 acres
Impervious Area= 0 acres
Pervious Area= 0.28 acres
' b. Soils
1. Beausite gravelly sandy loam
' c. CN Values
1. Lawns/Landscaping = 86
CN = 98
' CN p ,j.u.,= 86
d. Time of Concentration= 5.00 minutes
' 1. Assume minimum practical time of concentration of 5.00 minutes for this small area.
f. Precipitation
' 1. P2=2.0"
2. P,o=2.9"
' PART C: HYDROLOGIC ANALYSIS
The proposed detention pond will be designed using the following performance
trequirements:
• Release the 2-year/24-hour pre-developed peak rate of runoff during the 2-
' year/24-hour developed design storm.
' • Release the 10-year/24-hour pre-developed peak rate of runoff during the 10-
year/24-hour developed design storm
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
i PRELIMINARY STORAGE VOLUME CALCULATIONS
PART D: SUPPORTING CALCULATIONS
Attached is the Hydrograph Methodology, which provides an outline of the steps used in
the level pool routing. The attached Hydrograph Methodology contains computer
generated calculations used to determine the preliminary size of the proposed detention
pond. Included are applicable basin summary information, hydrographs, a stage/storage
table for the conceptual detention vault, a stage/discharge table, and level pool table
summary.
i
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
iRenton Place #95-8005
HYDROGRAPH METHODOLOGY
STEP 1. Generate hydrographs for the 2- and 10-year/24-hour design storms, existing
site conditions.
' MOVE Basin 2EX to Hydrograph#1
Peak Rate of Runoff= 0.13 cfs
Volume of Runoff= 0.11 ac-ft
Time to Peak= 8.17 hrs
MOVE Basin 1 OEX to Hydrograph#4
Peak Rate of Runoff= 0.35 cfs
Volume of Runoff= 0.23 ac-ft
Time to Peak= 8.17 hrs
' GROUP FOUR,INC.
16030 Juanita-WoodinNille Way NE
Bothell,WA 98011
STEP 1
10/ 3/95 GROUP FOUR Inc. page 1
RENTON PLACE
#95-8005
Conceptual Drainage Analysis
---------------------------------------------------------------------
BASIN SUMMARY
' BASIN ID: 10EX NAME: 10yr:Existing Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 .23 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 .90 inches AREA. . : 2 . 23 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81. 00
TIME OF CONC. . . . . : 43 . 99 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . . 98 . 00
' TcReach - Sheet L: 185. 00 ns: 0.4000 p2yr: 2 . 00 s: 0. 0632
TcReach - Sheet L: 115. 00 ns: 0.4000 2yr: 2 . 00 s: 0. 1130
TcReach - Shallow L: 80. 00 ks: 5. 00 s:�. 250
PEAK RATE: 0. 35 cfs VOL: 0. 23 Ac-ft TIME: 490 min
BASIN ID: 2EX NAME: 2yr:Existing Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2 . 23 Acres BASEFLOWS: 0. 00 cfs
' RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 00 inches AREA. . .. 2 . 23 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 81. 00
TIME OF CONC. . . . . : 43 . 99 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . . . : 98 . 00
TcReach - Sheet L: 185. 00 ns: 0.4000 p2yr: 2. 00 s: 0. 0632
TcReach - Sheet L: 115. 00 ns: 0. 4000 2yr: 2 . 00 s: 0. 1130
TcReach - Shallow L: 80. 00 ks: 5. 00 s:�. 250
' PEAK RATE: 0. 13 cfs VOL: 0. 11 Ac-ft TIME: 490 min
' o
STEP 1 LIoM
' Hyd No. 1_
Hyd No, 4
4
u
' c
w
i
a
it
Hydrograph 4 (1Oyr/24hr Design Storm)
Hydrogra h 1 (2yr/24hr Design Storm)
3 6 9 12 15 18 21 24 27 30
Time in Hours
Hyd No. 1
Rate: 0. 13 cfs Time: 8. 17 hr
' Vol 0. 11 Ac-ft Int: 10. 00 min
Hyd No. : 4
•Rate: 0. 35 cfs Time: 8 . 17 hr
Vol 0.23 Ac-ft Int: 10. 00 min
' Renton Place #95-8005
' HYDROGRAPH METHODOLOGY
STEP 2. Generate hydrographs for the 2- and 10-year/24-hour design storms for the
on-site area to be detained, developed site conditions.
MOVE Basin 2DET to Hydrograph#2
Peak Rate of Runoff= 0.72 cfs
Volume of Runoff= 0.22 ac-ft
Time to Peak= 7.83 hrs
MOVE Basin IODET to Hydrograph#5
Peak Rate of Runoff= 1.18 cfs
' Volume of Runoff= 0.36 ac-ft
Time to Peak= 7.83 hrs
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
STEP 2
10/ 3/95 GROUP FOUR Inc. page 1
#95-8005 RENTON PLACE
Conceptual-Drainage-Analysis
__________
BASIN SUMMARY
' BASIN ID: 10DET NAME: 10yr:Detained Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 1. 95 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
' PRECIPITATION. . . . : 2 . 90 inches AREA. . : 0.85 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0.20 AREA. . : 1. 10 Acres
CN. . 98 . 00
' PEAK RATE: 1. 18 cfs VOL: 0. 36 Ac-ft TIME: 470 min
BASIN ID: 2DET NAME: 2yr:Detained Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 1.95 Acres BASEFLOWS: 0. 00 cfs
' RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0. 85 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
' ABSTRACTION COEFF: 0. 20 AREA. . : 1. 10 Acres
CN. . . . : 98 . 00
PEAK RATE: 0. 72 cfs VOL: 0. 22 Ac-ft TIME: 470 min
' 0
ro STEP 2
LEGEND
' Hyd No. 2_
Hyd No, 5......
w
u
c
*� ;Hydrograph 5 (10yr/24hr Design Storm)
H dro ra h 2 2 r/24hr Design Storm)
3 6 9 12 15 18 21 24 27
' Tine in Hours
Hyd No. : 2
' Rate: 0. 72 cfs Time: 7. 83 hr
Vol 0. 22 Ac-ft Int: 10. 00 min
Hyd No. • 5
Rate: 1. 18 cfs Time: 7. 83 hr
Vol 0. 36 Ac-ft Int: 10. 00 min
! Renton Place 495-8005
HYDROGRAPH METHODOLOGY
' STEP 3. Generate hydrographs for the 2- and 10-year/24-hour design storms for the
on-site bypass area, developed site conditions.
MOVE Basin 2BY to Hydrograph 43
Peak Rate of Runoff= 0.06 cfs
1 Volume of Runoff= 0.02 ac-ft
Time to Peak= 8.00 hrs
1 MOVE Basin 10BY to Hydrograph 46
Peak Rate of Runoff= 0.12 cfs
Volume of Runoff= 0.04 ac-ft
Time to Peak= 7.83 hrs
i
1
1
1
1 GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
1
STEP 3
' 10/ 3/95 GROUP FOUR Inc. page 1
#95-8005 RENTON PLACE
Conceptual Drainage Analysis
---------------------------------------------------------------------
BASIN SUMMARY
' BASIN ID: 10BY NAME: 10yr:Bypass Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0. 28 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
' PRECIPITATION. . . . : 2 .90 inches AREA. . : 0. 28 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . 98. 00
' PEAK RATE: 0. 12 cfs VOL: 0. 04 Ac-ft TIME: 470 min
' BASIN ID: 2BY NAME: 2yr:Bypass Site Conditions
B
UH METHODOLOGY
TOTAL AREA. . . . . . . : 0. 28 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
PRECIPITATION. . . . : 2 . 00 inches AREA. . : 0.28 Acres
TIME INTERVAL. . . . : 10. 00 min CN. . . . : 86. 00
TIME OF CONC. . . . . : 5. 00 min IMPERVIOUS AREA
' ABSTRACTION COEFF: 0. 20 AREA. . : 0. 00 Acres
CN. . . . : 98. 00
PEAK RATE: 0. 06 cfs VOL: 0. 02 Ac-ft TIME: 480 min
r
o
.; STEP 3 LEMO
Hyd No, 3_
Hyd No. 6 .
w
U
C
M
y
Q
' H ydrograph 6 (10yr/24hr Design Storm)
H dro rah 3 2 r/24hr Design Storm)
3 6 9 12 15 h 21 A 27
Time in Hours
Hyd No. • 3
' •Rate: 0. 06 cfs Time: 8. 00 hr
Vol 0. 02 Ac-ft Int: 10. 00 min
Hyd No. : 6
Rate: 0. 12 cfs Time: 7.83 hr
' Vol 0. 04 Ac-ft Int: 10. 00 min
1
' Renton Place #95-8005
HYDROGRAPH METHODOLOGY
' STEP 4: Perform the level pool routing. Note that the allowable release rates have
been adjusted to account for undetained, developed flows from the bypass
area.
' Use Stage/Storage Table 1 & Stage/Discharge Table 1.
2YR STORM: Developed Inflow Hydrograph#2
Peak Inflow=0.72 cfs
' Controlled Outflow Hydrograph#10
Peak Outflow= 0.11 cfs
Peak Stage= 144.29'
Required Volume= 3,389.20 cf
' 1 OYR STORM: Developed Inflow Hydrograph#5
Peak Inflow= 1.18 cfs
' Controlled Outflow Hydrograph#11
Peak Outflow= 0.32 cfs
Peak Stage= 145.49'
Required Volume=4,274.06 cf
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
STEP 4
' 11/29/95 GROUP FOUR Inc. page 1
RENTON PLACE
#95-8005
Conceptual Drainage Analysis
' ----------
---------
===LEVEL POOL TABLE SUMMARY=====__________________
AGE
' _----____ ---------------- MATCH INFLOW � � �_< A >--__STOR
<--------
DESCRIPTION---------> (cfs) (cfs) -id --id <�STAGE> id VOL (cf)
2YR STORM .................... 0.11 0.72 1 1 144.29 10 3389.20 cf
' 10YR STORM ................... 0.32 1.18 1 1 145.49 11 4274.06 cf
1
1
STEP 4
' 11/29/95 GROUP FOUR Inc. page 1
RENTON PLACE
#95-8005
' Conceptual_Drainage_Analysis
______________________
STAGE STORAGE TABLE
RECTANGULAR VAULT ID No. 1
Description: Conce tual Detention Vault
Length: 36. 90 f . Width: 20. 00 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-
139.70 0.0000 0.0000 141.20 1107 0.0254 142.70 2214 0.0508 144.20 3321 0.0762
139.80 73.800 0.0017 141.30 1181 0.0271 142.80 2288 0.0525 144.30 3395 0.0779
139.90 147.60 0.0034 141.40 1255 0.0288 142.90 2362 0.0542 144.40 3469 0.0796
140.00 221.40 0.0051 141.50 1328 0.0305 143.00 2435 0.0559 144.50 3542 0.0813
140.10 295.20 0.0068 141.60 1402 0.0322 143.10 2509 0.0576 144.60 3616 0.0830
' 140.20 369.00 0.0085 141.70 1476 0.0339 143.20 2583 0.0593 144.70 3690 0.0847
140.30 442.80 0.0102 141.80 1550 0.0356 143.30 2657 0.0610 144.80 3764 0.0864
140.40 516.60 0.0119 141.90 1624 0.0373 143.40 2731 0.0627 144.90 3838 0.0881
140.50 590.40 0.0136 142.00 1697 0.0390 143.50 2804 0.0644 145.00 3911 0.0898
140.60 664.20 0.0152 142.10 1771 0.0407 143.60 2878 0.0661 145.10 3985 0.0915
140.70 738.00 0.0169 142.20 1845 0.0424 143.70 2952 0.0678 145.20 4059 0.0932
140.80 811.80 0.0186 142.30 1919 0.0440 143.80 3026 0.0695 145.30 4133 0.0949
140.90 885.60 0.0203 142.40 1993 0.0457 143.90 3100 0.0712 145.40 4207 0.0966
' 141.00 959.40 0.0220 142.50 2066 0.0474 144.00 3173 0.0729 145.50 4280 0.0983
141.10 1033 0.0237 142.60 2140 0.0491 144.10 3247 0.0745
' STEP 4
11/29/95 GROUP. FOUR Inc. page 2
RENTON PLACE
' #95-8005
Conceptual Drainage Analysis
---------------------------------------------------------------------
STAGE DISCHARGE TABLE
' MULTIPLE ORIFICE ID No. 1
Description:
Outlet Elev: 139.70
' Elev: 137.70 ft Orifice Diameter: 1. 3755 in.
Elev: 144 . 40 ft Orifice 2 Diameter: 2. 6309 in.
STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE--->
t (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- -------
----------------------------------------------------------------------------
139.70 0.0000 141.20 0.0629 142.70 0.0889 144.20 0.1089
139.80 0.0162 141.30 0.0649 142.80 0.0904 144.30 0.1101
' 139.90 0.0230 141.40 0.0669 142.90 0.0918 144.40 0.1113
140.00 0.0281 141.50 0.0689 143.00 0.0933 144.50 0.1719
140.10 0.0325 141.60 0.0708 143.10 0.0947 144.60 0.1976
140.20 0.0363 141.70 0.0726 143.20 0.0961 144-.70 0.2177
140.30 0.0398 141.80 0.0744 143.30 0.0974 144.80 0.2347
' 140.40 0.0430 141.90 0.0762 143.40 0.0988 144.90 0.2499
140.50 0.0459 142.00 0.0779 143.50 0.1001 145.00 0.2637
140.60 0.0487 142.10 0.0795 143.60 0.1014 145.10 0.2765
140.70 0.0513 142.20 0.0812 143.70 0.1027 145.20 0.2884
' 140.80 0.0538 142.30 0.0828 143.80 0.1040 145.30 0.2997
140.90 0.0562 142.40 0.0844 143.90 0.1052 145.40 0.3104
141.00 0.0585 142.50 0.0859 144.00 0.1065 145.50 0.3206
141.10 0.0607 142.60 0.0874 144.10 0.1077
1
O
STEP 4 LEGEND
2YR/24HR DESIGN STORM Hgd No, 2_
Hyd No. 10
w
a
c
�o
�o
a
' H dro ra h 2 (Developed Inflow
H dro ra h 10 Controlled Outflow)
6 12 18 24 30 36 42
Tine in Hours
Hyd No. : 2
Rate: 0.72 cfs Time: 7.83 hr
Vol 0.22 Ac-ft Int: 10. 00 min
Hyd No. : 10
Rate: 0. 11 cfs Time: 15. 00 hr
Vol 0. 22 Ac-ft Int: 10. 00 min
o
STEP 4 LEGEND
10YR/24HR DESIGN STORM H9d No. 5_
Hyd No. 11......
w
u
c
MO
�O
Q
' H dro ra h 5 (Developed Inflow
' H dro ra h 11 Controlled Outflow)
6 i2 i8 24 30 36 42 48
Time in Hours
Hyd No. : 5
Rate: 1. 18 cfs Time: 7. 83 hr
Vol 0. 36 Ac-ft Int: 10. 00 min
Hyd No. : 11
Rate: 0. 32 cfs Time: 9. 00 hr
Vol 0. 36 Ac-ft Int: 10. 00 min
Renton Place #95-8005
HYDROGRAPH METHODOLOGY
' STEP 5: Calculate the post-developed peak rate of runoff, which is a combination of
the controlled outflow hydrographs and the bypass area hydrographs.
' Post-Developed Peak Rate of Runoff=Bypass+ Controlled Outflow
2yr Post-Developed Peak Rate of Runoff:
ADD Hydrograph#10 +Hydrograph#3 =Hydrograph#13
' Peak Rate of Runoff=0.13 cfs
Volume of Runoff= 0.24 ac-ft
' Time to Peak= 8.00 hrs
10yr Post-Developed Peak Rate of Runoff:
ADD Hydrograph#11 +Hydrograph#6 =Hydrograph #14
' Peak Rate of Runoff= 0.35 cfs
Volume of Runoff= 0.39 ac-ft
Time to Peak= 8.67 hrs
r
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' 0
STEP 5 LEcao
' 2YR/24HR DESIGN STORM . Hqd No, 3_
Hyd No. 10 ....
Hyd No. 13___
1
w
U
C
w
1
y
Q
H dro ra h 13 = H dro ra h 3 + H dro raph 10
(Post-Developed Peak Rate Of Runoff)
H dro ra h 10 Controlled Outflow)
' H dro ra h 3 (Bypass)
6 12 18 24 30 36 42
Time in Hours
Hyd No. : 3
' Rate: 0. 06 cfs Time: 8 . 00 hr
Vol 0. 02 Ac-ft Int: 10. 00 min
Hyd No. : 10
Rate: 0. 11 cfs Time: 15. 00 hr
' Vol 0. 22 Ac-ft Int: 10. 00 min
Hyd No. : 13
Rate: 0. 13 cfs Time: 8. 00 hr
Vol 0.24 Ac-ft Int: 10. 00 min
' o
STEP 5 UGEW
10YR/24HR DESIGN STORM Hqd No, 6
Hyd No, 11,.._.._
Hyd No. 14
1
r
4
u
i
r
Y
r
Hydrograph 14 - Hydrograph 6 + Hydrograph 11
(Post-Developed Peak Rate of Runoff)
' H dro ra h 11 Controlled Outflow)
1
'---__ Hydrograph 6 (Bypass)
6 12 18 24 30 36 42 48
Tine in Hours
Hyd No. : 6
Rate: 0. 12 cfs Time: 7. 83 hr
Vol 0. 04 Ac-ft Int: 10. 00 min
Hyd No. : 11
Rate: 0. 32 cfs Time: 9. 00 hr
' Vol 0. 36 Ac-ft Int: 10. 00 min
Hyd No. : 14
Rate: 0. 35 cfs Time: 8. 67 hr
Vol 0. 39 Ac-ft Int: 10. 00 min
1
r
1
1
1
1
' Renton Place #95-8005
' HYDROGRAPH METHODOLOGY
' STEP 6: Compare the pre-developed peak rate of runoff (calculated in Step 1) with
the post-developed peak rate of runoff (calculated in Step 5) to ensure that
the performance requirements are met.
' 2YR STORM: Pre-Developed Peak Rate of Runoff= 0.13 cfs
(Hydrograph#1)
' Post-Developed Peak Rate of Runoff= 0.13 cfs
(Hydrograph#13)
' 10YR STOHN: Pre-Developed Peak Rate of Runoff= 0.35 cfs
' (Hydrograph#4)
Post-Developed Peak Rate of Runoff= 0.35 cfs
' (Hydrograph#14)
1
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
o
STEP 6 1E00
2YR/24HR DESIGN STORM Hyd No. 1_
Hyd No. 13
w
u
y
YD NO. 13
HYD. NO, 1
6 12 18 24 30 36 42
Time in Hours
Hyd No. : 1
' Rate: 0. 13 cfs Time: 8. 17 hr
Vol 0. 11 Ac-ft Int: 10. 00 min
Hyd No. : 13
Rate: 0. 13 cfs Time: 8. 00 hr
Vol 0.24 Ac-ft Int: 10. 00 min
1
' 0
a STEP 6 LEGEND
' 10YR/24HR DESIGN STORM Hyd No. 4_
Hyd No, 14......
4
C
w
1
Y
a
H`{D NO A
D N0.4
' 6 12 18 24 30 36 42 48
Tine in Hours
Hyd No. : 4
Rate: 0. 35 cfs Time: 8. 17 hr
Vol 0.23 Ac-ft Int: 10. 00 min
Hyd No. : 14
Rate: 0. 35 cfs Time: 8 . 67 hr
Vol 0. 39 Ac-ft Int: 10. 00 min
' Renton Place #95-8005
1
VII. APPENDIX
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
1
Ex. C8 _
EX. C8 TOP-140.81
EX. 12- CONC CU VERT TOP-173.59 IE.12' OONC. N.S. 134.11
IE.-172.01 IE.12• RCP. N. 170.77
IE.12• RCP. S. 171 19 170 '� =
i
172
N
J
ee l
.,�4 SCALE: 1" =4 0'
146
176
04
152
EX CS
000000' \ \ \ \ \ \ \ 1 TOP-_t 52.83
( \ \ \ \ \ f� \ \ \ \ 1 CONC.C.8" CMP.S N.
S. 146.79
ARE .Z�` •E a \ \ \ \ �` \ ` \ �,'� IE.12• CONC. W. 146.58
do
1 zorlc. �. 1 10 1
ice` i NZAW
�h
1
190
~ �` _fq.�.-.- 11 -�.v_�.^-•q+•__� T_••r}_C=i.d--�.. _�.i �� ` `� �. ` C f' `, \ \ \ 1 �a'qL l - \ \ '' ... I I .� i' �,�4
.' 11
_ - - f 12 CONC STORM LINE TO EAST
, f -� � •-� , _�.;-�►- _ - t nee e�`
.r
s
- _..._. yam....__,
n 1t
EX. C8 -- - -M- —----- - - -_• _ _- - - - EX. CB
TOP-165.22
TOP-191,18 Cs
- 1E.12" CONIC. Sw. 160.32
IE. 1 S' CONC. E. 167.55 EX CB 64.73
IE.12" CONC. N. 182.05
TOP-173.80
IE. 15• OONC w-NE 163.62
15• CONIC STORM LINE TO EAST
i
1
t
f {
JOB NO: 95-8005
GR 0 UP FOUR Inc.
16030 JUANITA-WOODINVILLE WAY NE RENTON PLACE
BOTHELL,WASHING TON 88011 BASIN MAP
(206)775-4581 * (2 EXISTING06)362-4244 * FAX(206)362-3819
SURVEYING ENGINEERING PLANNING MANAGEMENT
DRAWN BY. CHECKED BY: APPROVED BY:
DATE: DATE: DATE: CITY OF RENTON WASHINGTON