20101019063407119.pdfw
tn'
Z3
I -j
CJ
07
cQ
of
01
{(7
�2
cU
LO
CV
�tiLr)
co
OD
G)
t3 W
(D
(D
(D
00
if
(zi
u
CD
0
CD
Ln
0
Lo
(D
uj
-5 'oCa
CD
Gi
to
U')
00
"?
�
CD
Ca
CD
(Z)
CD
SII
CD
IP
C)
l9
CD
10
'n
0
C3
c
C-)
00
(Z)
C)
C)
ol
C)
fl
LO
LO
0
CD
CD
C)
C)
a
r–
Q0
C)
C-�
�2
m
C,
0
C)
C3
E-
ate:,
06
r
4
(D
EF
co
00
C,
I--
a) 3t
—
IQ
Lq
ll7
> C,
C
CD
6
141
0)
m
co
co
C)
m
C>
LD
t -
CD
C�
C'�LO
U)
CN
C)
0
m
m
ro
C)
0
—
�L:
co
0
CD
LL}
a)CD
0
LO
>
Ci
c)
c6
rq
C)
U�
CD
C�
C-)
C�
LO
V-
LO
N
0
m
6
CD�
(0
m
7r
It
0
w
E
0
-
co
>-
>-
rz
UJ
Ea)L
E°'
co
It
2
w
tn'
Z3
I -j
CJ
of
(113 -k
CV
�tiLr)
C -i
if
(zi
w
tn'
I -j
QL
(113 -k
w
QL
Z�
if
w
�Nn 2 �
Ln
two,
N LD
ro IE .
wa
-S
lL2
Lit
qqq Q yr ft -�� Ss O
Ixt -K
z5 i DR'NIL, Lyd•_ 0.
T
Q? _^_�h r s' Pvc ~ a it
I
z o., 2g Q
xQ�Sc� fi zo h C+j �
CID
�ME� m C� viz •� " CL a �� t
U4
MRS -� o � �`'is a _w,_z--
Z5 Ad
LU
CN 4i
I
al x
x
IT
x w L6
N
RNY
YlF6931d,aga 1 -'
��
z
f v mss 1 .i ...A
SOY= -09 Old
I
.. YO'l @ 31d
cs
pp x �C
X411 vF
-0 d
N\ s,& Oz leu c3
Mt tom- cold q - - to
STORMWATER MANAGEMENT MANUAL FOR THE PUGET SOUND BASIN pe,6
inlet control conditions, which may be present or anticipated in the system,
are not specifically addressed.
Each pipe within the system is sized and sloped such that its barrel capacity at
normal full flow (computed by Manning's Equation) is equal to or greater than the
25 --Year design flow. The nomograph in Figure III -2.1 can be used for an approximate
solution of Manning's Equation. For more precise results, or for partial pipe full
conditions, solve Manning's Equation directly:
V = 1.49 R213 s112
n
or, using the continuity equation, Q = AV
where:
Q = 1.49 ARz'Y'2
n
Q = Discharge in cfs
V = Velocity in fps
A = Area in ft2
n = Manning's roughness coefficient in 8-ft116 (see
Table III -2.2)
R = Hydraulic radius = area/wetted perimeter, in ft.
s = Slope of the energy grade line in ft/ft
For pipes flowing partially full, the actual velocity may be estimated from the
hydraulic properties shown in Figure III -2.1 by calculating Qft,jj and VF„p and using
the ratio of Qd«ign/Qto find V and d ( depth of flow).
Table III -2.2 provides the recommended Manning's "n" values for preliminary design
using the Uniform Flow Analysis Method for pipe systems. (Note, the "n" valves for
this method are 15% higher in order to account entrance, exit, junction, and bend
head losses.)
Table III -2.2 Manning's "n" Values for Pipes
Type of Pipe Material
Analysis Method
Backwater Uniform
Flow Flow
A. Concrete pipe and CPEP-smooth interior pipe
B. Annular orruga a Me i e or Pipe Arch:
1.2-2/3 x corrugation riveted)
a. plain or fully coated
*b. paved invert (40% of circumference paved):
(1) flow full depth
(2) flow 0.8 depth
(3) flow 0.6 depth
c. treatment 5
2.3" x 1" corrugation
3.6" x 2" corrugation (field bolted)
C. Helical 2-2/3" x 1/2" corrugation and CPEP-
single wall
D. Spiral rib metal pipe and PVC pipe
E. Ductile iron pipe cement lined
F. High density polyethylene pipe (butt fused
0.014 0.012
0.028
0.021
0.018
0.015
0.015
0.031
0.035
0.024
0.018
0.016
0.013
0.013
0.027
0.030
0.028
0.024
0.013
0.011
0.014
0.012
only) 0.009
0.009
111-2-6 FEBRUARY, 1992'
June 25, 2010
City of Edmonds
Attn: Jennifer" Lambert
12.1 5 I .Ave. North
Edmonds, WA 98020
M ° E....
6621 Foster Slough Rd. Ph: 425-334-9980
Snohomish, WA 98290 Fax: 425-334-7380
e -►nail: donnabreske(&,comcast.net
" r
C
v,
v 4
�!tM;�
i
SubJect: SCC) Miniunum Requirements 2-10 per E',CDC 18.30,060.13
Reference: SFR located at 7510 162"d St. SW, Plan Check #: BLD20100314
1 � ,r- t iq 7 , �PO, A� ; v .� IJ
Per f CCD 18.30.010.A.A ` "Natural drainage course" means the location of the
channels, swales, and other non -manmade conveyance systerns as defined by the earliest
documented topographic contours existing for the subject property, either frorn maps for -
photographs, or such other means as appropriate.' No such natural drainage course or courses
exists on the site and hence this requirement is not applicable.
Household chemicals and lawn & garden products frorn the single family home have a
minirnum potential for contarnination of storm water flows, The homeowner is expected to
read and follow manufactures directions on such products and follow them accordingly.
.r f
VITIIMIf,MIWM Ni,
RLInoff Treatment for the pollution generating surface consisting of pavement is
provided with the installation of a. Type 1 catch basin near the driveway entry to the site. This
Type 1 catch basin provides a sump area for collection of sediment prior to release of storm
flows to the city conveyance system.
This requirement applies only to situations where storm water discharges directly or
indirectly through a conveyance system into a wetland. That is not the case with the discharge
from this site and therefore this requirement does not apply.
Mike Gold, 7510 162nd St. S. W. Page 1 of 2
SCO Minimum Requirement 6: Water Quality Sensitive Areas:
Per this section of code, "Where local governments determine that the minimum
requirements do not provide adequate protection of water quality sensitive areas, either on site
or within the basin, more stringent controls shall be required to protect water quality." This
section does not apply. No such determination has been made by the city of Edmonds.
Furthermore, there are no water quality sensitive areas associated with this site development to
be protected.
SCQ Minimum Requirement 7: Off Site Analysis and Mitigation:
An analysis of off-site water quality impacts resulting from the project has been
addressed in the Direct Discharge Report prepared by this engineer and dated April 5, 2010.
The report verifies that the downstream conveyance system has adequate capacity to convey
storm drainage flows released from the site.
SCO Minimum Requirement 8: Basin Planning:
There is no adopted and implemented watershed -based basin plan. Hence, this
minimum requirement does not apply.
SCO Minimum Requirement 9: Operation and Maintenance:
The applicable operation and maintenance schedule for proposed catch basin storm
water facility is attached.
SCQ Minimum Requirement 10: Financial Liability:
Per city review comments dated June 8, 2010 a $50,000 performance bond will be
required prior to issuance of the permit. The owner intends to post this bond and thus the
requirement will be fulfilled.
Sincerely,
Donna L. Breske, P.E.
Attachment:
Operation and Maintenance Schedule for Catch Basin
Mike Gold, 7510 162nd St. S.W. Page 2 of
M
No. 5— Catchy Basins
Maintenpnee
Defect
Conditions When Maintenance. is Needed
Resufts txppeted When
Component
:.Maintenance is
•
_performed
General
Trash &
Trash or debris which is located immediately
No Trash or debris located
Debris
in front of the catch basin opening or is
blocking inletting capacity of the basin by
immediately in front of
catch basin or on grate
more than 10%.
opening.
Trash or debris (in the basin) that exceeds 60
No trash or debris in the
percent of the sump depth as measured from
catch basin,
the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case.
less than a minimum of six inches clearance
from the debris surface to the invert of the
lowest pipe.
Trash or debris in any'inlet or outlet pipe
Inlet and outlet pipes free
blocking more than 1/3 of its height.
of trash or debris.
Dead animals or vegetation that could
No dead animals or
generate odors that could cause complaints
vegetation present within
or dangerous gases (e.g., methane)-
the catch basin.
Sediment
Sediment (in the basin) that exceeds 60
No sediment in the catch
percent of the sump depth as measured from
basin
the bottom of basin to invert of the lowest
pipe into or out of the basin, but in no case
less than a minimum of 6 inches clearance
from the sediment surface to the invert of the
lowest pipe.
Structure
Top slab has holes larger than 2 square
Top slab is free of holes
Damage to
inches or cracks wider than 114 inch
and cracks.
Frame and/or
Top Slab
(Intent is to make sure no material is running
into basin).
Frame not sitting flush on top slab, i.e.,
Frame is sitting flush on
separation of more than 314 inch of the frarne
from the top slab. Frame not securely
the riser rings or top slab
and firmly attached.
attached
Fractures or
Cracks in
Basin Walls/
Maintenance person judges that structure is
unsound.
Basin replaced or repaired
to design standards.
Bottom
Grout fillet has separated or cracked wider
Pipe is regrouted and
than 1/2 inch and longer than 1 foot at the
secure at basin wall.
joint of any inlet/outlet pipe or any evidence of
soil particles entering catch basin through
cracks. .
Settlement!
If failure of basin has created a safety,
Basin replaced or repaired
Misalignment
function, or design problem.
to design standards.
Vegetation
Vegetation growing across and blocking more
No vegetation blocking
than 10% of the basin opening-
opening to basin.
Vegetation growing in inlettoutlet pipe joints
No vegetation or root
that is more than six inches tall and less than
growth present.
six inches apart.
4-36 Volume V —Runoff Treatment BMPs August 2001
No. 5 - Catch Basins
Maintenance ,::.
Defect
Cionditions Wheri'Maintenance is Needed
esUlts Expected When.::
Compvri nt
:Maintenance is
'.;.
ertdrtl}ed
Contamination
See "Detention Ponds" (No. 1),
No pollution present.
and Pollution
Catch Basin
Cover Not in
Cover is missing or only partially in place.
Catch basin cover is
Cover
Place
Any open catch basin requires maintenance.
closed
Locking
Mechanism cannot be opened by one
Mechanism opens with
Mechanism
maintenance person with proper tools. Bolts
proper tools.
Not Working
into frame have less than 112 inch of thread.
Cover Difficult
On; maintenance person cannot remove lid
Cover can be removed by
to Remove
after applying normal lifting pressure.
one maintenance person.
(Intent is keep cover from sealing off access
to maintenance.)
Ladder.
Ladder Rungs
Ladder is unsafe due to missing rungs, not
badder meets design
Unsafe
securely attached to basin wall,
standards and allows
misalignment, rust, cracks, or sharp edges.
maintenance person safe
access.
Metal Grates
Grate opening
Grate with opening wider than 718 inch.
Grate opening meets
If Applicable)
Unsafe
design standards.
Trash and
Trash and debris that is blocking more than
Grate free of trash and
Debris
20% of grate surface inletting capacity.
debris.
Damaged or
Grate missing or broken member(s) of the
Grate is in place and
Missing.
grate.
meets design standards.
No. 6 - Debris Barriers (e.g., Trash Racks)
General
Metal
August 2001
Trash and
Debris
Damaged/
Missing
Bars.
Inlet/Outlet
Pipe
Trash or debris that is plugging more
than 20% of the openings in the barrier.
Bars are bent out of shape more than 3
inches.
Bars are missing or entire barrier
missing.
Bars are loose and rust is causing 50%
deterioration to any part of barrier.
Debris barrier missing or not attached to
pipe
Barrier cleared to design flow
capacity.
Bars in place with no bends more .
than 314 inch.
Bars in place according to design.
Barrier replaced or repaired to
design standards.
Barrier firmly attached to pipe
Volume V —Runoff Treatment BMPs
4-37