HomeMy WebLinkAboutCarl's Jr. Restaurant - Storm Drainage ReportPrepared For:
Erstad Architects and
City of Meridian
Engineers . Surveyors Planners
Carl's Jr. Restaurant
Meridian and Overland
Meridian, Idaho
Storm Drainage Report
Kelly Kehrer, P.E.
Principal Engineer
KM Engineering, LLP
9233 West State Street
Boise, Idaho 83714
208.639.6939
keliy@kmenglip.com
September 23rtl, 2013
Project No: 13-012
Table of Contents
Introduction and Summary:..
Project Description: ..............
Calculations....... _..................
................. I
...........................I .............
......................................... 2
Exhibits................................................................. _..-.._..................._.............................................3
Introduction and Summary:
The purpose of this report is to show that the storm drainage facilities are designed to
meet City of Meridian standards. All drainage calculations were derived using the
standard of one inch of stormwater over the impervious area. This methodology is
typically more conservative than the Rational Method, which is the standard method for
small catchments. Based on our calculations we verified that for the 100 year storm the
seepage beds are adequately sized.
Project Description:
This project is located at the south east corner of Meridian Road and Overland Road in
Meridian, Idaho. The proposed improvements include new structures, utility
connections, concrete hardscape, asphalt paving, drainage facilities, and landscaping.
All storm water for the proposed site sheet flows across the concrete asphalt where it is
collected by drop inlet and then piped to a sand and grease trap and disposed of
through underground infiltration facilities.
Basins:
There are five drainage basins:
Basin A: 2,015 ft.z (North Portion of Site)
Basin B: 1,350 ft.Z (North Portion of Site)
Basin C: 1,260 ft.z (East Portion of Site)
Basin D: 2,510 ft:Z (South Portion of Site)
Basin E: 2,540 ft.z (South Portion of Site)
See attached Drainage Basin Exhibit for additional information.
Seepage Beds:
Based on our ralrulationc all seepage beds are adequately sized to ensure no ponding
occurs or. the surface and ti -at storm Water will infiltrate within the seepage beds in as 24
hour period.
Once the size of the seepage bed is calculated the time necessary for infiltration of
storm water into the ground is calculated at less than five hours. The soils report
prepared by Strata, Inc. measured an infiltration rate of 8"/hr for soils we plan to
excavate the beds into, which we used for the drainage calculations.
The storm drainage, seepage bed and infiltration calculations are included in the
calculations section of this report.
Page I 1
Calculations
Page 1 2
STORM DRAINAGE CALCULATIONS
Project Description: Carl's Jr. Meridian and Overland
Date:
4/10/2013
Project No.: 13-012
Swale:
SW -A
STORM RUNOFF CALCULATIONS FOR BASIN "A"
Runoff Event Frequency:
100
year
METHOD: 1" STORM OVER IMPERVIOUS AREA
Design storm event for the 100 -year storm is for 1" of storm
water over the entire tributary area
Area
2,0150
ft2
Intensity
1.0
in
VOLUME TO BE RETAINED =
167.9
ft3
SWALE #:
SW -A
Runoff Volume (per other calculations):
167.9
ft3
Sediment Storage:
15.0
%
Volume Required (VR):
193.1
ft3
Depth:
1.0
ft
High Water Level Area:
132.0
ft'
Bottom of Swale Area:
0.0
ft2
Average End Area:
66.0
ft2
Average Depth:
1.0
ft
Swale Volume Provided: 66.0 ft3
INtILI KA 1lQN:
900,6 infiltration is 24 hours
Volume to be infiltrated:
Infiltration Rate
Infiltration Area
Volume Retained in Filter Sand:
First Hour Infiltration
Volume Provided (VP):
Time to infiltrate:
167,9 ft3
8 in/hr
132,0 ft2
66 ft3
88 ft3
220.0 ft3 OK, VP> VR
1.9 hr OK, < 24 hours
STORM DRAINAGE CALCULATIONS
Project Description: Carl's Jr. Meridian and Overland
Date:
9/10/2013
Project No.: 13-012
Swale:
SW -B
STORM RUNOFF CALCULATIONS FOR BASIN "B"
Runoff Event Frequency:
100
year
METHOD: 1" STORM OVER IMPERVIOUS AREA
Design storm event for the 100 -year storm is for 1" of storm
water over the entire tributary area
Area
1,350.0
ft2
Intensity
1.0
in
VOLUME TO BE RETAINED =
112.5
ft3
SWALE If:
SW -B
Runoff Volume (per other calculations):
112.5
ft3
Sediment Storage:
15.0
%
Volume Required (VR):
129.4
11:3
Depth:
1.0
ft
High Water Level Area:
90,0
ft,
Bottom of Swale Area:
0,0
ft2
Average End Area:
45.0
ft2
Average Depth:
1.0
it
Swale Volume Provided:
45.0
ft3
INFILTRATION:
90% Infiltration is 24 hours
Volume to be infiltrated: 112.5 ft3
Infiltration Rate S in/hr
Infiltration Area 90.0 ft,
Volume Retained in Filter Sand: 45 ft3
First Hour Infiltration 60 ft3
Volume Provided (VP): 150.0 ft3
Time to infiltrate: 1.9 hr
WM
OK, VP>VII
OK, < 24 hours
STORM DRAINAGE CALCULATIONS
Project Description: Carl's Jr. Meridian and Overland
Date:
9/10/2013
Project No.: 13-012
Swale:
SW -C
STORM RUNOFF CALCULATIONS FOR BASIN "C`
Runoff Event Frequency:
100
year
METHOD: 1" STORM OVER IMPERVIOUS AREA
Design storm event for the 100yearstorm is for 1" of storm
water over the entire tributary area
Area
1,260.0
ft'
Intensity
1.0
in
VOLUME TO BE RETAINED =
105.0
It
SWALE p:
SW -C
Runoff Volume (per other calculations):
105.0
ft,
Sediment Storage:
15.0
%
Volume Required (VR):
120.8
ft'
Depth:
1.0
ft
High Water Level Area:
90.0
ft
Bottom of Swale Area:
0.0
it
Average End Area:
45.0
ft'
Average Depth:
SA
It
Swale Volume Provided:
45.0
ft3
INFILTRATION:
90% infiltration is 24 hours
Volume to be infiltrated:
Infiltration Rate
Infiltration Area
Volume Retained in Filter Sand:
First Hour Infiltration
Volume Provided (VP):
Time to infiltrate:
In
105.0 ft,
8 in/hr
90.0 ft,
45 ft3
60 ft3
150.0 ft? OK, VP > VR
1.8 hr OK, <24 hours
STORM DRAINAGE CALCULATIONS
Project Description: Carl's Jr. Meridian and Overland Date: 9/10/2013
Project No.: 13-012 Swale: SW -D
STORM RUNOFF CALCULATIONS FOR BASIN "D"
Runoff Event Frequency: 100 year
METHOD: 1" STORM OVER IMPERVIOUS AREA
Design storm event for the 100 -year storm is for 1" of storm
water over the entire tributary area
Area 2,510.0 ftz
Intensity 1.0 in
VOLUME TO BE RETAINED = 209 2 ft3
bwALt 9: SW -D
Runoff Volume (per other calculations): 209.2 ft3
Sediment Storage: 15.0 %
Volume Required (VR): 240.5 ft3
Depth:
1.0
ft
High Water Level Area:
150.0
ftz
Bottom of Swale Area:
0.0
ft,
Average End Area:
75 0
ftz
Average Depth:
1.0
ft
Swale Volume Provided:
75.0
ft3
INFILTRATION:
90% Infiltration is 24 hours
Volume to be infiltrated:
Infiltration Rate
Infiltration Area
Volume Retained in Filter Sand:
First Hour Infiltration
Volume Provided (VP):
Time to infiltrate:
kM
209.2 ft3
& in/hr
150.0 ft"
75 ft3
100 It,
250.0 ft3 OK, VP > VR
2.1 hr OK, < 24 hours
STORM DRAINAGE CALCULATIONS
Project Description: Carl's Jr. Meridian and Overland
Project No.: 13-012
Date:
Swale:
9/10/2013
SW -E
STORM RUNOFF CALCULATIONS FOR BASIN "E"
150.0
ft2
Runoff Event Frequency:
100
year
METHOD: 1" STORM OVER IMPERVIOUS AREA
75.0
ft'
Design storm event for the 100 -year storm is for 1" of storm
1.0
it
water over the entire tributary area
75.0
ft3
Area
2,540.0
ft2
Intensity
1.0
in
VOLUME TO BE RETAINED =
211.7
ft3
SWALE p:
SW -E
Runoff Volume (per other calculations):
211.7
ft3
Sediment Storage:
1.5.0
%
Volume Required (VR):
243.4
ft3
Depth:
1.0
It
High Water Level Area:
150.0
ft2
Bottom of Swale Area:
0.0
112
Average End Area:
75.0
ft'
Average Depth:
1.0
it
Swale Volume Provided:
75.0
ft3
IFIL I KA F ION:
90% Infiltration is 24 hours
Volume to be infiltrated:
Infiltration Rate
Infiltration Area
Volume Retained in Filter Sand:
Frst Hour Infiltration
Volume Provided (VP):
Time to infiltrate:
211.7 ft'
8 in/hr
150.0 ft'
75 ft3
100 ft3
250.0 ft3 OK, VP> VR
2.1 hr OK, <24 hours
Exhibits
Page 13
o
u
Q
m
0
FF = 2626.59'
-------
CL,
, C'e
BASIN E
0
lam0 20 40 80 120
ENGINEERS. SURVEYORS. PLANNERS Flan Scale
9233 WEV STATE SIBEET
BOISE, IDAHO 93714
PHONE(208)639-6939
FAX 1208)639-6930 CARL'S JR. RESTAURANT
DATE. 923-2013 OVERLAND AND MERIDIAN DRIVE, MERIDIAN, ID
PROJECT: 13-012
SHEET: DRAINAGE BASIN EXHIBIT
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