HomeMy WebLinkAboutBLD2003-00437 Stormwater Mgmnt Plan di
F.O. box 720 • 11309 Clear Creek Road N.W.
Silverdale,Washington 95383
Silverdale (360) 692-5525 • Seattle (206) 652-5574
{ '� Fax(360) 698-0546
'N, .41 V_-_.
1 T
_ y tl % Engineering • Surveying • Planning
r
;
1i- 7t i OF r"�'t`-'°re ,: 01-PLATY
TO: Michelle Farfan
CIO: Dept. of Community Development
621 Sheridan Street
Port Townsend, WA 98368
FROM: Tim Wallis
DATE: 4-25-03
RE: SMITH PROPERTY STORM DRAINAGE (Tax No. 821-175-001)
Dear Michelle,
Please find enclosed the drainage computations, basin map, downstream
analysis and minimum requirements checklist for the above referenced project. If
you have any questions, feel free to contact me at the phone number above or
via email at i1fl1 l Li niasr-11111i1CCi.Co111.
Sincerely
L:-.-1,L------pli--:-----
Tim Wallis
• (Th
•
DRAINAGE INPUTS
Rainfall:
6 month, 24 hour storm = 0.96 in.
100 year, 24 hour storm = 3.25 in.
Impervious Area Being Treated: ` �
New Driveway = 6,000 SF JUN 2 0 2003 E I P
Arena/Stable = 7,080 SF ,� �.y
Total = 13,080 SF or C.3 Acres
APPROVE ER'x)N courori
STORMWATE iNiTY CEYELCiF ENI
HYDROGRAPH ANALYSIS
Runoff: JUL - 9 2003
0.06 CFS
JEFF ERSO OUN
DEPT.OF CO [}E. OPMENT
CONCLUSION: SIGNATURE: !�
Treatment of the 6 month, 24 hour design orm will require a bioswale
216 feet long at a slope of 1% with a 2-foot bottom width and side slopes
of 3H:1V. It is intended to convey runoff from the new impervious surfaces
via roadside ditch to 2 new catch basins where stormwater will then be
collected and transported to the bioswale though short segments of closed
conveyance pipe (see-Storm Drainage Plan).
DOWNSTREAM ANALYSIS:
Following treatment and run-out from the bioswale, stormwater will
sheetflow out across the Smith Property toward the SE corner of the
parcel. From there, as migration downgrade progreses it will infiltrate, or,
during wet winter months, continue to sheetflow approximately 1,500 feet
south to the Beaver Valley Road. Slopes along this route average about
12% and no visible running water or streambank conditions are observed
to exist.
This conveyance path converges at a low point in the ditch along the north
edge of the Beaver Valley Road. From this ditch, any surface or
subsurface runoff from Beaver Valley Road and from upgrade (as
described) runs through a culvert under the road. It then traverses the
ditch along the NW side of Paradise Road flowing SW about 1,250 feet at
a slope of approximately 6.4% and into the headwater of Ludlow Bay (see-
Basin Map).
•
S S} ^^
tl �
JUN 2 0 2003
MINIMUM REQUIREMENTS CHECKLIST: f L ..___ .,
Jr RSON COUNTY
L PEP Cr- Cna,,. .A , DEVELoPM
Minimum Requirement #1: (This requirement was addressedin full a -- -
part of the Erosion Control Plan previously submitted).
Minimum Requirement#2: Preservation of Natural Drainage Systems.
Stormwater will be discharged from the bioswale on the subject
property and will follow the pre-developed natural drainage path
described in the downstream analysis. Therefore, this requirement
will be met.
Minimum Requirement #3: Source Control Pollution.
91 This site is a single-family residence with stables for equestrian
usage and no hazardous materials will be stored. There will be no
fueling areas, nor will there be other types of activities commonly
associated with the need for source control BMP's. Therefore, this
requirement will be met through determination of non-significance.
Minimum Requirement #4: Runoff Treatment BMP_
The proposed bioswale was sized conservatively to treat
stormwater from post-developed impervious surfaces per D.O.E.
requirements. Therefore, this requirement will be met.
Minimum Requirement #5: Streambank Erosion Control.
Stormwater from this site will be via sheetflow and streambank
conditions do not exist downstream. Therefore, this requirement will
be met through determination of non-significance.
Minimum Requirement #6: Wetlands.
No wetlands exist on-site or downstream, therefore, this
requirement will be met through determination of non-significance.
Minimum Requirement #7: Water Quality Sensitive Areas.
No water quality sensitive areas are known to exi t claw-At-IT-ROVED
this project. Therefore, this requirement will be m t thrtMWATER PLAN
determination of non-significance.
JUL - 0 2003
JEFFER 0 - JU
DEPT.OF CO ELOPMEI
SIGNATU •
Minimum Requirement#8: Off-Site Analysis and Mitigation.
No off-site water quality impacts are anticipated to occur as a result
of this project. Under most seasonal conditions it is expected that
treated stormwater from the 6-month design storm will infiltrate soils
before it leaves the site. If sheetflow does occur during the wet
winter months, there can be no appreciable pooling due to
topography until it reaches the ditch along Beaver Valley Road.
This is 1,500 feet downstream, 180 feet beyond the mile
minimum for this requirement. Therefore, this requirement will be
met.
Minimum Requirement#9: Basin Planning.
Basin planning for the purpose of modifying these requirements will
not be necessary, because minimum requirements 2 through 11
can be met without doing so.
Minimum Requirement #10: Operations & Maintenance.
VMowing of the bioswale will be required to ensure it operates
properly. On this site, the bioswale will be located within the pasture
area where mowing will be required so horses may have maximum
use of the property. Also, mowing may not even be necessary
because the horses will be allowed to graze on overgrown swale
grasses at their leisure. Therefore, this requirement will be met.
Minimum Requirement #11: Financial Liability.
If Jefferson County requires a performance bond be posted before
approving this project, the owner will do so, therefore, this
requirement will be met.
APPROVED EGEll t7
STORMWATER PLAN
JUN 2 0 2003 11
JUL - 9 20°3
EFFERN LOOP? E?4T /ITY
JEFFERS, /COU % Y
DEPT.OF COtgjy$ y 0fr EI.OPMENT
SIGNATURI J , J
•
•
0.'S•'§b _�``w. �� ! - r r:� ' •i ' # I •tt (','. `l Nt #•N
. .."".•-••-•...m!' ..._.
•
----.:.-. • • -1:i;-rd. t.t I• , .•
lir c •
s
*'— r-k- "��" , t' w t 'tip `• t t, 4``
fi sr��1 ~ ff -1 za; ►r•..Y Imo- i:l•tt,l 1 ` .. 7;t -,,
-W12 4t5 w rr r t - Q i'';` - .,,- �'`.•.. \ l'A r '''t• r
j ';1 N. t i t ,/"ire'. - �- !ti--
,-,� _.,:„ -�-y• ___ '1 f. • i It ' '\ - t \ .:4 + ,1V •`� tom' 'i t , •.
-.� a \` '. ?}jt y`�:•e �� r `,.• • _- ! Imo\' `{j f� al.FJ:' • �rf
-W722'-4�75 •.r ! r-•i `S (}_ r E, ): i
•
' `` "' '")•' t -<�_. y,4 - ice': t 5 s ,_
- '`"f` ��` _'''`yam'f` �' V.I. pppp¢ =�: t.t't } J
•
'.'.:....� ` `�"•_ •,-.;\�' . `�-- ti• S\� .' ;T�'+Z: - 1 +1 {>s • '�i it I
i ' '!'_ • . I
/ r t l= f
•
{/. • .• `"' I. 1R pia. =,a`= i '`•_. -, % - `
•
•
N'i'_'_`42.25'- -_-� 1 _ f !f 4 may;
•-w127242_5 v _-_- -. _ ; _
l -11/4 \
• . E: cEFF, = a
-W1zz'•42-35' • - „ • - {r `, -,Q ? OF t$tp il:i�i� l;'�' ,.0 T;_..,•
r • _,r,-- G w.-r.w�rw•c:+-,r,�r•R�_�.-�.• —��j-'•^'�1� .a— n•• • l :4 `_ -.•.-
•.+—• ------ �—I••.� _-'i - .-."'- -�"• -j< I_...:,--f+r. , a�•�•-.•,y� -- -- — - -r r• •_
-W12•r-43• .` g �Tt�, N�VVAT .'-`'`•
-` %`*•..~ '- �----.���� :...,� ``- `;a""-' �.,
•
~'_•--�- - �'" `-...��.. '. 'ter:_iii y,r '"c
•
I -
-- s--ty -u - �- 1•l�t` , ' -1. .
- m -' ``
_-_.....
- _ rr. Il � Y 1
re
•
STORMWATER MANAGEMENT MANUAL % [
}.\ 0. 1L > 1 w1-07-t,121BASIN
\C-C t t j _______________________
124 12II '-'' t'
49. —---1. 11 I 1 � 1 1 :1' ' 121
n ►, `..'; 1 a a 4s .. era s.. w nima1m lie ism :o
`a, c.*,tyrBE. r .n. y A ve ,, . s a
,,,,,L.,,,,toio
FRIDAY HARBOR/• VO PORT STANLEY ��� 30 7� 1 PIr .i�.i�,
rap (( \•• MT V 's,V� �J ` r ! �`.i►. 73
35
��Af t-z� u�, 3025\20� 15/ 1U�\ \\ 1 (v\v
48 . �� 5 ;•�R' kays_ „!.� \ >� ` � lC R \i. a
•
45 1f 5 �� 39 `$ �,—r
50'. -�,l / 3 ! S{��IV ;'ri • s✓. �i J ` i; \ �•
p , ,;., hit` • 1 .;,C rti ,;0 ,
'X,. ' 't., .:2-i--->-1-45 40 15)p...;,t ,-,\C-- .• -‘.-=',---. - _---' *-. ------- - --S c• nc-----
i' 12-7\^�� ram.
: ,:-...:--_if'. ,_,./_,.._,/, ,! / --•/,, ,.,,, (c.._ Fif,,,,u . 14 ,,,,,... _:.,,,,
25VR 35' �0'
c.
.4
,..e, , '
• .. - ' 1)'\\
1 ts"--,/-*,--N_.. 50-Th\--) X -, ,
. t `� i .. --- a ��� O 1 20
\ a M • c 45c6Us'40 3 t J ,
` �--� ,
46 35 3SS
2 t Ca' 45 L ss ADA
` �u 45 �-- I _ —��—
�n3 25 ; i
WASHINGTON ... �
10 0 10 20 30 •
•..,: , PPt EN E
40
2
MILES LIMO 15 `
Figure 25 S TOR i 1\ I:AO A ' eI �-
2��_' AIL 2, Volume IX
ISOPLUVIALS F 2-YR 24-HR PRECIPITATION IN repared by .S.Department of C merce
TENTHS OF A INCH ationelOce nicandAtmospheric ministration
ationel We they Service,Office of Hydrology
J U L — 9 2003 repared for U.S.Department of Agriculture,
oil Consery tion Service,Engineer ng Division
124 123
JEFFERSO NT 121
OP PT Or COM t:V ' PMl• -.
SIG .kg.— FEBRUARY, 1992
. • f�.
I
STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN
124 .-r-- \i22 121
4 91 €...,m s Cz e -- 1 •
1 _ 4 1.-..,,_ 80 :1 :.I
I 3• 12,c‘.V\ ' tIL 141,„r.r.ANNO1 5 ,
li r)1 )1114 re-2°). '-ci - ,--,-t-ra) rw i .\ c
\„ oi
F a''' fJ • J �a;4'4_
7 ;i:ILLA ' F OF. .cnc7 :i: '1 ' + Wpugi' . �'1 r
'. y - ,
Z
/�8085 7 35 0_`\ 1° 4 "t _ i n• •
'-6p 75 1 — , — - T --k7 — - __y 4v.• `4,' "c4 40
\4 ' - 1 25. 11
mg
25 ..,,.---- \,. \\ 35\ " :•\_:-- illk i OA: ---)Icil
k 'Q1 . r-f`it, �'� f�����
80 \ �`` 1. / • \ hiss;. ,,
90.
(, - \_\ \\‘N.--.; ' - ;.\1 6 ,k?t/.5110
I l; �I -V- / !'r N
6R-\ 1 /v// Kt :Pg1pr 1�� ✓ - �, (gyp •,� 6�� I��1 .
, 6,5, -.\ \\‘•,;;_.)00 i ___F,/,/,/ li. / ; —) ,. , ,.,-,____ s -.....LA N-•.:—\40-' - ---"-
70_r r 35�
4� 1, i 4 � -'_t��(4(JV/�( ( 7--- GS ``f,2
so. U. LEE 5. % .� � :ALI 65 •
f 6O ` r G?Nr50 1•
1;z S�j 22
45
ar/ 70 4 r i R s �10 T' so 2
I 75 L q `� I l
II 60 i � "�� u \�
1D0 CS
�22�• '
•
III ( 55
sd ' } - 45 `o--- if
/
, K._ \ '
• 55l ' O.
� f 70 s �, i /
1 ss 1 8 V 1 6 . 1 if
I 55 1 65 I /
\6i*.-60'
rl ,�0I 'e ADAM / 30\ ^�25.
46I 55 ��o w r1 ' or :� �/4 �~ . " 50 40WASHINGT q° i to() u; - , ;_,,, ENP E •tCKLI
10 0 10 20 30 40 \\ gp till - J• r� z
-----i ---1 MILES `� 0�� �I 5_ L M o rc'J
Figure 30 \N I ` av� •• , Volume II
ISOPLUVIALS F 100-YR 24-HR PRECIP1T4T101.1 grr t le' '- ?IU•14 Flgpartm- t of C merce
• Atmo •heric ministration
IN TENTHS OF N INCH National west er Service,,Nice of Hydrology
Prepared for U .Departm: t of Aviculture,
Jill _ rvSoi aFrvat•n Service, ngineer g Division
124 y J
12s 122 121
III-1-46JEFFE'SO FEBRUARY, 1992
DEPT.OF C� , • I.I.OPMENI'
SIGNATU',/
•
HYDROGRAPH REPORT
NUMBER : 1
TYPE : SANTA BARBARA
DESCRIPTION : 6 MONTH 24 HOUR STORM
[HYDROGRAPH INFORMATION]
Peak Discharge = 0.06 (cfs)
Volume = 0.02 (acft)
Time Interval = 0.02 (hr)
Time to Peak = 7.90 (hr)
Time of Base = 24.00 (hr)
Multiplication factor = 1.00
[BASIN DESCRIPTION]
Watershed Area = 0.30 (ac)
Curve Number = 98
[RAINFALL DESCRIPTION]
Distribution Type = SCS IA
Total Precipitation = 0.96 (in)
Return Period = 2 (yr)
Storm Duration = 24.00 (hr)
Impervious Fraction = 0.00 (hr)
[TIME CONCENTRATION -- USER DEFINED]
Time of Concentration = 5.00 (min)
VA
!\ }4' P
APPROVED \\:' ``
STORMWATER PLAN'-<
JUL - 9 2003
JEFFERSON UNT
DEPT.OF COM Y D: PMENT
SIGNATURE-
HYDROGRAPH REPORT
NUMBER : 2
TYPE : SANTA BARBARA
DESCRIPTION : 100 YEAR 24 HOUR STORM
[HYDROGRAPH INFORMATION]
Peak Discharge = 0.23 (cfs)
Volume = 0.08 (acft)
Time Interval = 0.02 (hr)
Time to Peak = 7.88 (hr)
Time of Base = 24.00 (hr)
Multiplication factor = 1.00
[BASIN DESCRIPTION]
Watershed Area = 0.30 (ac)
Curve Number = 98
[RAINFALL DESCRIPTION]
Distribution Type = SCS IA
Total Precipitation = 3.25 (in)
Return Period = 100 (yr)
Storm Duration = 24.00 (hr)
Impervious Fraction = 0.00 (hr)
[TIME CONCENTRATION -- USER DEFINED]
Time of Concentration = 5.00 (min)
;fis.
\CIFS\
APPROVED
STORMWATER PLAN L ` `
JUL - 9 2003
JEFFERSON U
DEPT.OF C'OM 1 Y D :LUPMf.N'P
SIGNATURE:
• .
6/17/03
RICHARD SMITH PROPERTY
BIOSWALE SIZING COMPUTATIONS Pg. 1 of 2
FOR TRAPEZOIDAL CHANNEL
Bio-Swale (Kentucky Bluegrass&Tall Fescue)
Actual Depth at 6 Mo. Storm
Inputs: n= 0.2 max.
s= 0.023 ft./ft. 1-6% max.
Q= 0.06 cfs 6 mo. Post Storm
Z= 3 ft./ft. Side Slopes
b= 2 ft. Bottom Width
Using Mannings Equation
Qmatch R y trial V
cfs A sq.ft. ft. ft. fps
0.051 0.2300 0.0874 0.1000 0.22
0.055 0.2431 0.0912 0.1050 0.23
0.060 0.2563 0.0951 0.1100 0.23
0.065 0.2697 0.0989 0.1150 0.24
0.070 0.2832 0.1026 0.1200 0.25
0.075 0.2969 0.1064 0.1250 0.25
0.080 0.3107 0.1101 0.1300 0.26
0.086 0.3247 0.1138 0.1350 0.26
0.091 0.3388 0.1174 0.1400 0.27
0.097 0.3531 0.1210 0.1450 0.28
0.103 0.3675 0.1246 0.1500 0.28
0.109 0.3821 0.1282 0.1550 0.29
0.116 0.3968 0.1317 0.1600 0.29
0.122 0.4117 0.1353 0.1650 0.30
0.129 0.4267 0.1388 0.1700 0.30 k
0.136 0.4419 0.1422 0.1750 0.31
0.143 0.4572 0.1457 0.1800 0.31 \:,
0.150 0.4727 0.1491 0.1850 0.32 ' ,M
V=Q/A So, V= 0.23 ft/sec ° t
V=0 .23 ft/sec< 1.5 ft./sec. (OK) s '` J`Vi VO {.
•
L= (V)(t)(60 sec/min) APPROVED
For t= 20 min. L= 276 feet STORMWATER PLAN
JUL 9 2003
JEFFERSON COUNT
DEPT.OF COM I): MEW
SIGNATUR'.
I
6/17/03
RICHARD SMITH PROPERTY
BIOSWALE SIZING COMPUTATIONS Pg. 2 of 2
STABILITY CHECK
n = 0.2 max.
s= 0.023 ft./ft. 1-6% max.
Q= 0.23 cfs 100 yr. Post Storm
Z= 3 ft./ft. Side Slopes
b= 2 ft. Bottom Width
Using Mannings Equation
Qmatch R y trial V
cfs A sq.ft. ft. ft. fps
0.17 0.5200 0.1593 0.2000 0.33
0.18 0.5361 0.1626 0.2050 0.34
0.19 0.5523 0.1659 0.2100 0.34
0.20 0.5687 0.1693 0.2150 0.34
0.20 0.5852 0.1726 0.2200 0.35
0.21 0.6019 0.1758 0.2250 0.35
0.22 0.6187 0.1791 0.2300 0.36
0.23 0.6357 0.1823 0.2350 0.36
0.24 0.6528 0.1856 0.2400 0.37
0.25 0.6701 0.1888 0.2450 0.37
0.26 0.6875 0.1920 0.2500 0.37
0.27 0.7051 0.1952 0.2550 0.38
0.28 0.7228 0.1983 0.2600 0.38 :.-
0.29 0.7407 0.2015 0.2650 0.39 .. �� .-- .--.,\\
'�.
0.30 0.7587 0.2046 0.2700 0.39 , e ,�
0.31 0.7769 0.2078 0.2750 0.40 C`\ .. -- \`�
0.32 0.7952 0.2109 0.2800 0.40 .. s ``-e'
0.33 0.8137 0.2140 0.2850 0.40 ` " 2 0 i
\\, b
V=Q/A So,V= 0.36 ft/sec ,\.' '` e CC�yE\-Cpl O
V=0..36 ft/sec<5 ft./sec. (OK) 1 OF�'�`
G
l,n
APPROVED
STORMW ATER PLAN
JUL p- 9 2003
JEFFER • bUNT
DEPT.OF CO,� I"PY DE " . MIEN'1'
SIGNArIJ4pr`� '4