HomeMy WebLinkAboutSWP272217(1) 1
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TECHNICAL INFORMATION REPORT
1
RENTON PLACE
' CITY OF RENTON, WASHINGTON
tGROUP FOUR JOB 995-8005
GROUP FOUR, Inc.
16030 Juanita-Woodinville Way AIE
' Bothell, WA 98011
FAX(206)362-3819
(206) 775-4581 • (206)362-4244
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1
TECHNICAL INFORMATION REPORT
1
1
1 REWON PLACE
1 CITY OF RENTON, WASHNGTON
1
1 4-Z-96E
1 tiN0. VA,
OF WH
1 �31�f9
�ONAL�cyG� "
1 EXPIRES 03/08/98
1
' April 2, 1996
1
Prepared For: Prepared By:
1 Bob Tozer GROUP FOUR, Inc.
PO Box 53312 16030 Juanita-Woodinville Way NE
1 Bellevue, WA 9801 5-3 3 12 Bothell, WA 98011
Phone: (206) 228-9731 (206) 362-4244 • (206) 775-4581
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iRenton 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).
tSITE 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.
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GROUP FOUR, INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Page 1 of 2
King County Building and Land Development Division
TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
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PROJECT ENGINEER AND DESCRIPTION
' Project Owner BOB TOZER Project Name RENTON PL./,CF,,
AddressPD BOX 53312,BELLEVUE,95015 Location 23N
Phone (206)228- 9731 Township
Project Engineer CARMEN 6• V^NIER Range 5E
Company GROUP FOUR, INC• Section 1G
Address Phone (Z06) 362 42L14 Project Size 2.23 AC
Upstream Drainage Basin Size _�AC _
1 ® Subdivision Q DOF/G HPA Q Shoreline Management
Short Subdivision Q COE 404 Q Rookery
' a Grading Q DOE Dam Safety Structural Vaults
Q Commercial Q FEMAFloodplain Q Other
Q Other Q COE Wetlands ED HPA
PART 5 SITE COMMUNITY AND DRAINAGE-BASIN
Community
Drainage Basin Q`
o
Q_River Q Floodplain
' Q Stream Q Wetlands
Q Critical Stream Reach Q Seeps/Springs
Q Depressions/Swales Q High Groundwater Table
Q Lake Q Groundwater Recharge
O Sleep Slopes � Other COAL MIN 5 H^Z A R D
Q Lakeside/Erosion Hazard
PART 7 SOILS
Soil Ty Slopes Erosion Potential Erosive Velocities
' BEAUSPTL 6- 15 % MoDERATI". MEDIUM
Q Additional Sheets Atlatched
' 1/90
1 Page 2 of 2
King County Building and Land Development Divlslon
1 TECHNICAL INFORMATION REPORT (TIR) WORKSHEET
PART 8 DEVELOPMENT UMITATIONS
J
1 REFERENCE LIMITATIOWSITE CONSTRAINT
1 Ej Ch.4-Downstream Analysis
0
1
0
0
1 (] it onal Sheets Attatched
MINIMUM ESC REQUIREMENTS MINIMUM ESC REQUIREMENTS
DURING CONSTRUCTION FOLLOWING CONSTRUCTION
Sedimentation Facilities Stabilize Exposed Surface
1 (� Stabilized Construction Entrance ® Remove and Restore Temporary ESC Facilities
® Perimeter Runoff Control Clean and Remove All Sill and Debris
(] Clearing and Grading Restrictions ® Ensure Operation of Permanent Facilities
1 E::] Cover Practices 0 Flag Limits of NGPES
1� Construction Sequence Other
(] Other
PART 10 SURFACE WATER SYSTEM
1 CRI Grass Lined Channel E�:] Tank 0 Infiltration Method of Analysis
Pipe System 0 Vault F--j Depression 551.1I-}
(] Open Channel L-1 Energy Dissapator 0 Flow Dispersal Compensation/Mitigation
1 ED Dry Pond 0 Welland (] Waiver of Eliminated Site Storage
E:1 Wet Pond 0 Stream O Regional Detention
Brief Description of System Operation cDNVEY DEVELDPE0 STORK WATER RUNOFF IN
1 UNDFr"�GROUND PIPE DIrCHES TO NETVAULr/DET-ENrIbN VAULT.
Facility Related Site Limitations
Reference Facility Limitation Additional Sheets Attatched
1
PART 11 STRUCTURAL ANALYSIS
(May require speM s1ruiftural review)
[�jt Drainage Easement
ElCast in Place Vault Other VAUL 0 Access Easement
Retaining Wail E] Native Growth Protection Easement
1 Rockery>4'High Tract
(] Structural on Steep Slope (] Other
PROFESSIONAL
1 I or a civil engineer under my supervision have visited the site. Actual �) /I�'
site conditions as observed were incorporated into this worksheet and the�G�} !�-i'• V
attatchments. To the best of my knowledge the information provided �'l.(-Qh
here is accurate. sp,.e-n.r. 3_Z
1190
' Renton Place #95-8005
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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
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TIR SECTION II
Preliminary Conditions Summary
GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
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Figure 3-Basin Map
Scale I" = 1,000'
' 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
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GROUP FOUR, INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
' OFF-SITE ANALYSIS
' 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"011
' Renton Place #95-8005
1
TIR SECTION IV
' Retention Detention Analysis & Design
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
tRenton Place *95-8005
t 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
Impervious 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 v�q = 98
' CN a,„_= (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
1. P2=2.0'
2. P10=2.9"
' GROUP FOUR,INC
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
+
' EX /2' CONC. CULbERT TOP-173.5
II 140.81
IE.-172.01 IE12' RCP.. TOP-
N. 17 ,7O _
,2' RCP. S. ,71.-19 IE12' CONC. N.
IE ,9 W _
'172-
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\ \ SO
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176 hill
SCALE V =40'
_ \ a•P a �' ON-SITE AREA = 2.2S ac�os \\ \\/ \�\\ \ 1� 11 I \\ \\ \1111 \ / / `6
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SHED I I x� I L1 ---- %64\ \ -�--- I-�-- V{'�{ I /
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JOB NO: 95-80
— — — \ i- \ -v • 0 68 w.. .... DATE:
m m m m m m m m m = = � m = m m m i m
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 bio5ltration 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°/u impervious=(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;,,w�,,.;a =98 CN P,„a,,,= 86
GROUPFOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
' Renton Place #95-8005
' PRELIMINARY STORAGE VOLUME CALCULATIONS
PART B: DEVELOPED SITE HYDROLOGY
L Basin_Input Parameters - Detained Area (con't1
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
' 1. P2=2.0"
2. P10= 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 = 98
CN,u a , = 86
' d. Time of Concentration= 5.00 thin
1. Assume a practical minimum time of concentration of 5.0 minutes for this relatively
' small, heavily developed property.
f. Precipitation
' 1. P2 = 2.0"
2. P10=2.9"
GROUP FOUR,INC
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
i
- - - --%i72---- IE.12" RCP. S. 171.13 , 4�
_ d FIST. 12' CONC. CULVERT #di. ` \, 5 \ I Fy
1V_� � IE.ay�201 I, I 1 , � t 5 tt I � �IIee
EXIST. I J 5 V It 5 I • X s
HOUSE j�4
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1 f SIGN {TYP.} � -JT -__ r"- 1"--1 --r- ` -�_ ...—...;.._..r...�_� \`♦ ` \ 1 I r "S
SCALE 1 "=40' 1/ -
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r kV
EXIST. 16" CI. H2O LINE
1 (PER CITY OF RENTON r ' \\ 5 5
i / / EXIST. SSNH. \ 1t 5
ASSUILS) � TOP-175.83
67,64 J � ,p $ i
'
/ • N I � to 8
(Rooftop 10 A4) / , 1 1
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/ r ; P\4ER 'VAULT \\ 7 �'
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METER�� / I 3 EXIST. ^ I( a>
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1 2 o A4)
1 1 (Rooftop to A4) 1 ¢ iN eox (r P A o
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-TaLBOr I 1 5 h t 1 c�
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WATER f
_-- w _ W `Ix
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-- w
— ^� '19I94 EXI 24" WATER MAIN (LOW PRESSURE) FROM RESERVOIR — fY - - �' ` I /r bb I I` I 6
, C ^ O' \ ^
' - - - -�- -6 - BYPASS 1 I _, w
/ � `� I i JOB N0: 85-80
/ -OWER POLE (TYP.) /" _ — — T — _ — — ._ — — — _ _ — — —. — — / — — — 1 ISB I DATE:
r c — — — — — — — — — —
' 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
t 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-how
' 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 stageldischarge table,and a level pool table summary.
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' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place 495-8005
t HYDROGRAPH METHODOLOGY
STEP 1. Generate hydrographs for the 2- and 10-year/24-hour design storms, existing
site conditions.
' MOVE Basin 2EX to Hydrograph 91
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= 0274 ac-ft
Time to Peak = 8.17 hrs
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' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
1
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. O9 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:O.4000 Kyr: 2 .00 s: 0. 1130
TcReach - Shallow L: 80. 00 ks:5.00 s:DD 11
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: O.4000 p2yr: 2 .00 s: 0. 0632
TcReach - Sheet L: 115. 00 ns: 0.4000 p2y2502 .00 s: 0. 1130
' TcReach - Shallow L: 80. 00 ks:5. 00 s:DD 11
PEAK RATE: 0. 18 cfs VOL: 0. 14 Ac-ft TIME: 490 min
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1 Renton Place 495-8005
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 I ODET to Hydrograph 95
' Peak Rate of Runoff= 1.370 cfs
Volume of Runoff= 0.416 ac-ft
Time to Peak= 7.83 hrs
' GROUP FOUR, INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
1 3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
1 #95-8005
_______________________
BASIN SUMMARY
1 BASIN ID: 10DET NAME: 10yr:Detained Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 2. 32 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
1 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
1 PEAK RATE: 1.37 cfs VOL: 0.42 Ac-ft TIME: 470 min
1 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
1 ABSTRACTION COEFF: 0.20 AREA. . : 1.22 Acres
CN. . . . : 98 . 00
PEAK RATE: 0.83 cfs VOL: 0.26 Ac-ft TIME: 470 min
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Renton Place #95-8005
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 #3
' Peak Rate of Runoff= 0.028 cfs
Volume of Runoff= 0.010 ac-ft
Time to Peak= 8.00 hrs
' MOVE Basin 10BY to Hydrograph 96
' Peak Rate of Runoff= 0.058 cfs
Volume of Runoff= 0.018 ac-ft
Time to Peak =7.83 hrs
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
1 3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
1 #95-8005
---------------______________________________________________________
BASIN SUMMARY
1 BASIN ID: 10BY NAME: 10yr:Bypass Site Conditions
SBUH METHODOLOGY
TOTAL AREA. . . . . . . : 0. 14 Acres BASEFLOWS: 0. 00 cfs
RAINFALL TYPE. . . . : USER1 PERVIOUS AREA
1 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
1 ABSTRACTION COEFF: 0.20 AREA. . : 0. 00 Acres
CN. . . . : 98. 00
PEAK RATE: 0. 03 cfs VOL: 0. 01 Ac-ft TIME: 480 min
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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 911
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
195-8005
LEVEL POOL TABLE SUMMARY
' MATCH INFLOW -STO- -DIS- <-PEAK-> STORAGE
<--------DESCRIPTION---------> (cfs) (cfs) --id- --id- <-STAGE> id VOL (cf)
=ec=ceo=ev=aces_see==ee=e=eeeeee-secs==ecece__________e==ececeee=vveeeeeeeev
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
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' 3/28/96 GROUP FOUR, Inc. page 3
' RENTON PLACE
#95-8005
STAGE STORAGE TABLE
RECTANGULAR VAULT ID No. 1
Description: Conceptual Detention Vault
Length: 36.90 ft. 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 0.01111 139.80 1587 0.0364 141.30 2694 0.0618 142.80 3801 0.01173
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
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1 3/28/96 GROUP FOUR, Inc. page 4
1 RENTON PLACE
#95-8005
------------------------STAGE DISCHARGE TABLE ----_-------_-----_----
1 MULTI$LEORIFICE ID No. 1
Description:
Outlet Elev: 137.65
1 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...> STAGE <--DISCHARGE--->
1 _(=t)= 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
1 137.80 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
1 138.30 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
1 138.70 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
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' 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:
tADD Hydrograph 410 +Hydrograph #3 =Hydrograph 913
' 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 411 +Hydrograph#6 =Hydrograph 414
' Peak Rate of Runoff= 0.432 cfs
Volume of Runoff= 0.434 ac-ft
Time to Peak= 8.67 hrs
1
' GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
1
' o
a LEGEND
' Hyd NO. 3_
Hyd No. 10......
Hyd No. 13
u
u
M
' 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
1
LEGEND
iHyd No, 6_
Hyd No, 11......
NO No. 14___
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1 `
0
M
1 i
i 6 1a 18 24 30 36
Tine in Hours
Hyd No. 6
1 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
1 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
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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 #13)
10YR STORM: Pre-Developed Peak Rate of Runoff= 0.432 cfs
(Hydrograph 44)
Post-Developed Peak Rate of Runoff= 0.432 cfs
(Hydrograph #14)
GROUP FOUR, INC.
16030 Juanita-Woodimille Way NE
' Bothell,WA 98011
3/28/96 GROUP FOUR, Inc. page 2
RENTON PLACE
#95-8005
HYDROGRAPH SUMMARY
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
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Renton Place #95-8005
t 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.
Input Data:
' 100-yr/24-hr Developed Overflow=Hydrograph#10 = 1.99 cfs (ax attached B.in summary)
Stage/Discharge Table=Riser Discharge ID No. 1 = Overflow Riser
Top of Riser= 143.20'
Riser Diameter= 12"
' Route Mdroaraph #10 through the Riser:
Peak Inflow= (Hydrograph #10)= 1.99 cfs
Peak Outflow= (Hydrograph#20) = 1.99 cfs
Peak Stage= 143.55' < 143.70' - ;K
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
1 #95-8005
_____________________________________________________________________
BASIN SUMMARY
1 BASIN ID: 1000F 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. 09 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
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3/29/96 GROUP FOUR, Inc. page 2
RENTON-PLACE=________________________________________________________
#95-8005
STAGE DISCHARGE TABLE
RISER DISCHARGE ID No. 1
Description: Overflow Riser
Riser Diameter (in) : 12 . 00 elev: 143 . 20 ft
' Weir Coefficient. . . : 3.782 height: 143 . 70 ft
Orif Coefficient. . . : 9.739 increm: 0. 10 ft
' STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE---> STAGE <--DISCHARGE--->
(ft) ---CfS-- ------- (ft) ---CIS-- ------- (ft) ---CfS-- ------- (ft) ---CfS-- -------
143.20 0.0000 143.30 0.3080 143.50 1.6003 143.70 2.6743
' 143.20 0.0000 143.40 0.8711 143.60 2.3919
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' 3/29/96 GROUP FOUR, Inc. page 3
' RENTON PLACE
#95-8005
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
' Renton Place #95-8005
I TIR SECTION V
Conveyance System Analysis & Design
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GROUP FOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
Renton Place #95-8005
i 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.Convevance System A(Uostream 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. onvgyance System B(Downstream of Detention Vault)
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.
' 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
i
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 =clA
Where: Q = peak rate of runoff(cfs)
A=total tributary drainage area(acres)
' c= runoff coefficient
I=peak rainfall intensity (iph)
tI, the peak rainfall intensity, is calculated below for the 25- and 100-year design storms:
' 25-year Design StMM:
P25 = 3.40"
Tc= 6.30 minutes (assumed minimum) a 25 =2.66
' i 25 = (2.66)(6.30) t-o.es>= 0.80 b25 = 0.65
125= (3.40")(0.80) = 3.20 iph
' 100-year Design Storm:
ptoo = 3.90"
' Tc=6.30 minutes (assumed minimum) a too= 2.61
b too =0.63
i too = (2.61)(6.30)<o.csl= 0.82
' I too= (3.90")(0.82)= 3.20 iph
The results of the analysis are tabulated below:
' IMPERVIOUS PERVIOUS I (25) Q (25) I (10D)of-sae on-sae off-sa Q (1 DO)
' 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 1 0.12 1 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
' Composite "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
t
1
' 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.
1
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 SUMMARY
1OOYR 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
'o (ft)=====(it) ft/ft
(cfs) (ft)==------
==(fps)===('ps'_______
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) ------ (it) ------ (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
1 3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
1 195=8005BACKWATER ANALYS_I_S___=______________________
REACH SUMMARY
100YR DESIGN STORM
1 Hydraulic Gradeline for Reach HGL1
<-FROR-> <--TO--> <FLW> floss Ent HGL EntLoss ExtLoss OutLet Inlet AppHesd BndHead JunHead HeadNtr -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
CB#2 155.84
INTAKE2A CB#2 0.93 1.56 tw & do <dc: Inlet Ctrl Assured 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 Assured 154.36 0.00 0.00 0.00 154.36 155.15
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' 3/28/96 GROUP FOUR, Inc. page 1
RENTON PLACE
#95-8005
----------------_____________________________________________________
REACH SUMMERY
' PIPE REACH ID No. P2
From: CB#2 To: VAULT
Pipe Diameter: 1. 00 ft n: 0. 0240
Pipe Len th 30. 00 ft s: 0. �000
' Up Inver 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 Cappacity 8.22 cfs
Design Vel 659 fps Travel Time: 0. 03 min
' Pipe Full Vel 10..74 fps
PIPE REACH ID No. P3
' FVom: CB#3 To: CB#2
Pipe Diameter: 1.00 ft n: 0.0240
Pip@ 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
Pipq Cappacity 7 . 00 cfs
Design Vel 650 fps Travel Time: 0. 05 min
Pipe Full Vel 9 .. 14 fps
PIPE REACH ID No. P3A
' From: INTAKE3A To: CB#3
P}pe 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 Floe 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
3/28/96 GROUP FOUR, Inc. page 2
' RENTON PLACE
#95-8005
__________________________________________________________________
REACH SUMMARY
' PIPE REACH ID No. P4
From: CB#4 To: CB#2
Pipe Diameter: 1. 00 ft n: 0. 0240
' 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
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 = 1.49AR2JS12
n
' Where: Q =flow rate (cfs)
Bottom Width= 0 (V-ditch cross section)
Side Slopes= 3(M:I(V)
Longitudinal Slope=varies
t 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
14.040/6 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-WoodinNillc Way NE
Bothell,WA 98011
1 Renton Place 495-8005
1 CONVEYANCE SYSTEM ANALYSIS & DESIGN
Drainage Ditch Analysis & Design
1 Conveyance System A
East Swale:
1 • Segment l: Grass-lined, slope varies from 3.59% - 12.9%
1 Q25= 0.79 cfs
Qioo = 0.93 cfs
Min. Sloe Max. Slope
1 3.59% 12.90%
25-yr Design Storm
Flow Depth (ft) 0.30 0.24
1 Velocity (fps) 2.86 4.63
100-yr Design Storm
1 Flow Depth (ft) 0.32 0.25
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1
1
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GROUP FOUR, INC.
16030 Juanita-Woodinville Way NE
1 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 CB41, 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.
i
1
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 HGO 1OOyr/24hr Overflow Analysis
<-FROM-> <--TO--> <FLW> 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--
' _________________vve=see=====________=====ace=====cease=veeeeceeeeeecc=========ceee=eeece=c=eeeeeecce_e=-=a==e
_________________
EXCB 134.59
C61 El(CB 1.99 1.02 tw 8 do <dc• Inlet Ctrl Assumed 135.42 0.10 0.13 0.00 135.45 146.00
VAULT CB1 1.99 10.62 tw & do <dc: Inlet Ctrl Assured 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
' Upol invert 135. 13 ft down invert: 134 . 11
Clection Area: 2 .32 Ac.
Design Flow 1. 99 cfs Dsgn Depth: 0. 48 ft
Pipe Cappacity 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
t
1
' Renton Place #95-8005
1
TIR SECTION VI
Special Reports & Studies
' GROUPFOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
tRenton Place #95-8005
i SPECIAL REPORTS & STUDIES
The following is a list of the special reports & studies prepared in support of the proposed
development:
• "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
t
' Renton Place #95-8005
TIR SECTION VII
Basin & Community Plan Areas
' N/A
GROUPFOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011
' Renton Place #95-8005
I TIR SECTION VIII
Other Permits
' N/A
GROUP FOUR, INC.
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
Renton Place 495-8005
TIR SECTION IX
Erosion/Sedimentation Control Design
' GROUP FOUR,INC
16030 Juanita-Woodinville Way NE
' Bothell,WA 98011
fRenton Place #95-8005
t 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:
iAverage lope Flow Path Length
1.5H:1 V 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:1 V or less (10%) 250'
The average slope across the site is approximately 8.63%.
Average Slope = (High Elev. - Low Elev.)
(Diagonal Distance from SW comer to NE comer)
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
' adjacent 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.
' GROUPFOUR,INC.
16030 Juanita-Woodinville Way NE
Bothell,WA 98011