532 DAYTON ST.PDFIIIIIIIIIIIIII
13880
532 DAYTON ST
DONNA L. BRESKE, P.E. 14712 Meadow Rd. Lynnwood, WA 98037
Phone: 425-742-6386 Fax: 425-787-9330
STORM DRAINAGE DETENTION REPORT
FOR
MICBEL CONSTRUCTION, INC.
DATE: OCTOBER 31, 2001
JANUARY 9, 2002 (REVISION # 1)
SITE: %ff &
EDMONDS, WA
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01
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RECEIVED
FED - 1 2-002
DEVELOPMENT SERVICES CTR,
CITY OF EDMONDS
DRAINAGE — DETENTION — INSPECTION — GRADING & TESC — SEWER & WATER
FEASIBELITY — SITE DEvELopmENT
Revision #1
lanuary 9, 2002
532 & 534 DAYTON STREET
REVISION 41 (Use CN=73 for second growth forest per city of Edmonds)
OVERVIEW:
Condominium are proposed for construction at 532 & 534 Dayton Street. The
site area to be developed is 11,000 square feet. Currently, there are two houses and
outbuildings located on the property. Both houses and the outbuildings are proposed for
removal.
DETENTION CALCULATIONS DISCUSSION:
Attached are calculations that result in a storm water detention pipe of 4 feet in
diameter and 94 feet long. Required detention volume is 1, 181 cubic feet. For
calculation purposes, it was assumed that there is no existing impervious area, and a
CN=73 for second growthfibrest was used. The developed impervious area is 6,675
square feet.
The SCS method was used for calculation purposes. In accordance with the
Washington State Department of Ecology Manual, the pipe is designed to detain flows
from the 2-, 10- and I 00-yr 24-hr storm events.- Per the Washington State DOE Manual,
flows released from the detention structure are to match one-half of the calculated flow
from the pre -developed 2-yr storm, and to match the pre -developed flows of both the 10-
and I 00-yr storms. However, due to the conservative value of CN=73, the calculated
pre -developed 2-year flow is 0.00 cfs. Some flow must be released for the 2-year storm,
or the pipe will never completely drain-. Therefore, the controlled released for the 2-year
storm is set at 0.01 cfs. A chart of the pre -developed, developed and controlled
developed release flows is shown below:
DESCRIPTION
PRE -DEVELOPED
FLOWS
DEVELOPED
FLOWS
CONTROLLED
RELEASE DEV FLOWS
2-M 24 HR
0.00
0.05
0.01
10-M 24 HR
0.01
0.08
0.01,
I 00-YR, 24 HR
0.02
0.13
0.02
R E c 1,7- 1 v = D
Revision #1
January 9,2002
F E B — I 2"Un "� 2
DEVELOPMENT SERVICE6 CYR
'�v na C:r)%A')%'nF,
g, 57
Sr3 2� .31 4,*,l 5t/
C-0 do
Edmond's
Ad
11'700-
Compley.
T3-pe Aiderwood Urbon LarlId
40
R��i;4(1 1-44-6-
P10 2. 0
P100 3, 0
EXISTIK6i CONDMONS - Tvm hboses 9- sheds ext��
otl +-he propeefy. i4oLA�Lee, +h&,� Will be Vemoved,
Heriee, c7ss4ime rio ext�f('n_q Irmper.utlous
Peru 1'oos 000 sF .25,3 A e-
Cross couer sD -75% ,f 4he arm .1 cN m -73
ga-Vel-OPED CoNID171OW&
)mpervtou,s jqu (I C(imq 5-7-7-7
Dr�ue &,-Walks "620
6�6 7 5- S F
15-S 6C
Al = �8
Peribus', 2-5-3 �r- -,/,53 AC
Lands.copiAg wf'+h MSG Cm = 50
cover on 5o - % o� 4he area
R E CLv- I V E D
FEB - 1 2.002
DEVELOPMENT SERVICES CTR.
CITY OF EDMONDS
I
1/ 8/02
page 1
JANtARY 8, 2002
532 & 534 DAYTON ST.
BASIN SUMMARY
BASIN ID: A10OX
NAME: 100 YR
24 HR
SBUH METHODOLOGY
TOTAL AREA ....... :
0.25 Acres
BASEFLOWS: 0.00 cfs
RAINFALL TYPE .... :
TYPEIA
PERVIOUS AREA
PRECIPITATION....:
3.00 inches
AREA..: .. 5 Acres
TIME INTERVAL .... :
10.00 min
CN.... 73.00
TIME OF CONC ..... :
23.35 min
IMPERVIOUS ARE -
ABSTRACTION COEFF:
0.20
AREA..: 0.00 Acres
CN.... : 98.00
PEAK RATE: 0.02
cfs VOL: 0.02
Ac-ft TIME: 490 min
BASIN ID: AlOX
SBUH METHODOLOGY
TOTAL AREA .......
RAINFALL TYPE ....
PRECIPITATION ....
TIME INTERVAL.....:
TIME OF CONC ..... :
ABSTRACTION COEFF:
NAME: 10 YR 24 HR EXISTING
0.25 Acres BASEFLOWS: 0.00 cfs
TYPElA PERVIOUS AREA
2.00 inches AREA. . : n--!> v; Acres
10.00 min CN.... : 73.0'
23.35 min IMPERVIOUS ��
0.20 AREA..: 0.00 Acres
CN....: 98.00
PEAK RATE: 0.01 cfs VOL: 0.01 Ac-ft TIME: 960 min
BASIN ID: A2X
SBUH METHODOLOGY
TOTAL AREA .......
RAINFALL TYPE ....
PR ECIPITATION ....
TIME INTERVAL ....
TIME OF CONC .....
ABSTRACTION COEFF:
TcReach - Sheet
PEAK RATE: 0.00
NAME: 2 YR 24- HR EXISTING
0.25 Acres
BASEFLOWS: 0.00 cfs
TYPElA
PERVIOUS AREA
1.30 inches
AREA..: Acres
10.00 min
CN....: 73.00
23.35 min
IMPERVIOUS
0.20
AREA..: 0.00 Acres
CN.... : 98.00
L: 100.00 ns:0.4000 p2yr: 1.30 s:0.0500
cfs VOL: 0.00
Ac-ft TIME: 1320 min
RECEZIV E: rj
j
FES - I 'Kn.,
DEVELOPMENT SERVICES CTR,
CITY OF EDMONDS
1/ 8/02
page 2
JANUARY 8, 2002
532 & 534 DAYTON ST.
BASIN SUMMARY
BASIN ID: B100D
NAME: 100 YR
24 HR DEVELOPED
SBUH METHODOLOGY
TOTAL AREA .......
0.25 Acres
BASEFLOWS:
0.00 cfs
RAINFALL TYPE-.:
TYPEIA
PERVIOUS AREA
PRECIPITATION .... :
3.00 inches
AREA..:
0.10 Acres
TIME INTERVAL .... :
10-00 min
CN....:
90.00
TIME OF CONC.....:
10-00 min
IMPERVIOUS
AREA
ABSTRACTION COEFF:
0.20
AREA..:
0.15 Acres
PEAK RATE: 0.13
cfs VOL: 0.05
CN....:
Ac-ft TIME:
98.00
480 min
BASIN ID: B10D
SBUH METHODOLOGY
TOTAL AREA .......
RAINFALL TYPE ....
PRECIPITATION ....
TIME INTERVAL ....
TIME OF CONC .....
ABSTRACTION COEFF:
NAME: 10 YR 24 HR DEVELOPED
0.25 Acres
BASEFLOWS:
0.00 cfs
TYPElA
PERVIOUS AREA
2.00 inches
AREA..:
0.10 Acres
10-00 min
CN.... :
90.00
10-00 min
IMPERVIOUS
AREA
0.20
A'D'P A *
r%
- j.5 ticres
CN.... 98.00
PEAK RATE: 0.08 cfs VOL: 0.03 Ac-ft TIME: 480 min
BASIN ID: B2D
NAME: 2 YR 24 HR DEVELOPED
SBUH METHODOLOGY
TOTAL AREA ....... :
0.25 Acres
BASEFLOWS: 0.00
cfs
RAINFALL TYPE .... :
TYPElA
PERVIOUS AREA
PRECIPITATION .... :
1.30 inches
AREA..: 0.10
Acres
TIME INTERVAL .... :
10-00 min
CN.... : 90.00
TIME OF CONC ..... :
10-00 min
IMPERVIOUS AREA
ABSTRACTION COEFF:
0.20
AREA..: 0.15
Acres
PEAK RATE: 0.05
cfs VOL: 0.02
I
CN.... : 98.00
Ac-ft TIME: 480
min
RECEIVrED
FEB - 1 200.2
DEVELOPMENT SERVICES CTR.
CITY OF EDMONDS
-8/02
JANUARY 8, 2002
53:2 & 534 DAYTON ST.
HYDROGRAPH SUMMARY
PEA.K
TIME
VOLUME
HYD
RUNOFF
OF
OF
Contrib
NUM
RATE
PEAK
HYDRO
Area
cfs
min.--cf\AcFt
Acres
1
0.002
1320
67
cf
0.25
2
0.006
960
291
cf
0.25
3
0.024
490
778
cf
0.25
4
0.046
480
783
cf
0.25
5
0.081
480
1363
cf
0.25
6
0.134
480
2228
cf
0.25
11
0.008
980
783
cf
0.25
12
0.011
1340
1363
cf
0.25
13
0.025
800
2099
cf
0.25
page 3
RECiElvEE)
FEB - 1 2002
DEVELOPMENT SERVICES CTR.
CITY OF EDMONDS
1/, 8/02
page 4
JANUARY 8, 2002
532 & 534 DAYTON ST.
STORAGE STRUCTURE LIST
UNDERGROUND PIPE ID No. Pi
Description: UNDERGROUND PIPE
Diameter: 4.00 ft Length: 94.0 1/ 8/02
JANUARY 8, 2002 MICHEL CONST.
532 & 534 DAYTON ST,
STORAGE STRUCTURE LIST
UNDERGROUND PIPE ID No. Pi
Description: UNDERGROUND PIPE
Diameter: 4.00 ft. Length: 94.00 ft.
Slope... : 0.0050 ft/ft
REcEIVED
FEB - 1 2002
DEVELOPMENT SERVICES CTR.
CITY OF EDMONDS
A 8/02
page 2
JANUARY 8, 2002
532 & 534 DAYTON ST.
DISCHARGE STRUCTURE LIST
COMBINATION DISCHARGE ID No. C1
Description: COMBINATION DISCHARGE
Structure: 01 Structure:
Structure: N1 Structure:
Structure:
NOTCH WEIR ID No. N1
Description: NOTCH WEIR
Weir Length: 0.0830 ft. Weir height (p): 2.0000 ft.
Elevation 103.40 ft. Weir Increm: 0.10
MULTIPLE ORIFICE ID No. 01
Description: ORIFICE
Outlet Elev: 100.00
Elev: 99.00 ft orifice Diameter: 0.5000 in.
RIEC=- IVEr)
npp
FEB 2P9
DEVELOPMENT SERVICES CTFI.
CITY OF EDMONDS
1/ 1 8102 page 3
,tANUARY 8, 2002
532 & 534 DAYTON ST.
LEVEL POOL TABLE SUMMARY
MATCH INFLOW -STO- -DIS- -<-PEAK-> STORAGE tia+Ch
< -------- DESCRIPTION -------- �> (cfs) (cfs) --id- --id- -STAGE> id VOL (cf) pmk
2 YR 24 HR ................... 0.00 0.05 Pl Cl 101.39 11 283.99 oOl
10 YR 24 HR .................. 0.01 0.08 pl Cl 102.45 12 669.34 #01
100 YR 24 HR ................... 0.02 0.13 Pl Cl 103.59 13 1052.04 . 02,
R E C E- I,., V E D
FEB - 1 K__
DEVELOPMENT SERVILB CTR.
CITY OF EDMONDS
Table 2.3
Runoff Curve Numbers for Selected Agricultural, Suburban, and Urban Areas
(Sources: TR 55, 1986, and Stormwater Mana2ement Manual, 1992. See Section 2. 1.1 for explanation)
I
Cover type and hydrologic condition.
CNs for hydrologic s2y!seu
A
B
C C1 D
. Curve Numbers for Pre -Development Conditions
Pasture, grassland, or range -continuous forage for grazing:
Fair condition (ground cover 50% to 75% and not heavfly grazed).
49
69
79 84
Good condition (ground cover > 75% and lightly or only occasionally grazed)
39
61
74 80
Woods: 1
Fair (Woods are grazed but not burned, and some forest litter covers the soil).
36
60
7 79
q0
Good (Woods are protected from grazing, and litter and brush adequately cover the soil).
30
55
77
Curve Numbers for Post-DeveloRment Conditions
Open space (lawns, parks, golf courses, cemeteries, landscaping, etc.)'
Fair condition (grass cover on 50% -� 75% of the area).
77
85
92
Good condition (grass cover on >75% of the area)
68
80
86 90
Impervious areas:
O�en water bodies: lakes, wetlands, ponds etc.
100
100
J0. 100
Paved parking lots, roofs�, driveways; etc. (excluding right-of-way)
98
98
n9 98
Porous Pavers and Permeable Interlocking Concrete (assumed as 85% impervious and 15% lawn)
Fair lawn condition (weighted average CNs).
95
96
97 97
Good lawn condition (weighted. average CNs).
94
95
96 97
Paved
98
98
98 98
Gravel (including right-of-way)
76
85
89 91
Dirt (including right-of-way)
72
81
87 89
Pasture, grassland, or range -continuous forage for grazing:
Poor 6ondition (ground cover <50% or heavily grazed with no mulch�
68
79
'96 89
Fair condition (ground cover 500/6 to 75% and not heavily grazed).
49
69
.79 84
Good condition (ground cover >75% and ligh fly or -only occasionally grazed)
39
61
74 80
I
Woods:
Poor (Forest litter, small trees, and brush are destroyed by heavy grazing or regular burning).
45
66
77 83
Fair (Woods are grazed but not burned, and some forest litter covers the soil).
36
60
73 79
Good (Woods are protected from grazing, and litter and brush adegfiateiy cover the soil).
30
55
10 77
Single family residential': Should only be used for Average Percent
Dwelling Unit/Gross Acre subdivisions > 50 acres impervious area 3.4
1.0 DU/GA 15
1.5 DU/GA
Separate
curve number
or
U—/, G 38
42
PUD's, condos, apartments, commercial %impervious Separate curve numbers shall
businesses, industrial areas & must be be selected for pervious and
& subdivisions < 50 acres comvuted impervious portions of the site
For a more detailed and complete description of land use curve numbers refer to chapter two (2) of the Soil Conservation Service's Technical
Release No. 55, (2 1 O-VI-TR-55, Second Ed., June 1986).
'Composite CN's may be computed for other combinations of open space cover type.
2
Where roof runoff and driveway runoff are infiltrated or dispersed according to the requkentents in Chapter 2,.the average percent impervious
area may'be adjusted in accordance with the procedure described under "Flow Credit for Roof Downspout Infiltration" and "Flow Credit for Roof
Downspout Dispersion" in Chapter 2.
3Assumes roof and driveway runoff is directed into. streettstorm system.
4All the remaining pervious area (lawn) are considered to be in good condition for these curve numbers.'
R
�ECE
7., F.
FE9 1-2602-
August 2001 -Volume M --Hydrologic-Analysis and Flow Control
BMPS
DEVELOPMENA %CE
S CTR.
C ITY wo
:-OF
-..EDMQ DS