HomeMy WebLinkAboutTomorrow's Hope - Intermediate Care Facility - Storm Water Management - Engineering Drainage ReportMarch 8, 2013
TOMORROW'S HOPE
INTERMEDIATE CARE FACILITY
MERIDIAN, IDAHO
STORM WATER MANAGEMENT - ENGINEERING DRAINAGE REPORT
OWNER
Thait Pond
2980 N. Meridian Rd.
Meridian, ID 83646
Ph: 208,319,0760
ENGINEER
Ti IE LAND GROUP, INC
Jason Densmer, PE
462 1 ?as t Shore Drive
Eagle, Idaho 83616
Ph: 208.939.4041
Fax: 208.939.4445
Project No. 112142
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SITE DESCRIPTION
The proposed development of Tomorrow's Hope Intermediate Care Facility is located at
2980 N. Meridian Road in Section 6 of Township 3N, Range IE, Ada County. The proposed
Intermediate Care Facility is located on 1.914 acres. The facility will include two residential
homes that will each house up to eight residents and be utilized to offer comprehensive
services to meet individual's needs. Residents are moderately to profoundly intellectually
disabled and need 24 hour supervision with some nursing requirements.
Off street parking and landscape improvements will be located at the front of the residences
that includes covered parking at the front sidewalk and fenced side yards for each residence.
PEAK RUN-OFF RATE & SYSTEM SIZING
100 -Year Event Areas (See Drainage Area Exhibit)
The proposed storm drainage runoff from the front half of each building will be collected in
gutters and will discharge to the parking area via downspouts. This runoff will sheet flow
across the asphalt to storm drain inlets. Storm water will flow through underground pipes to
a sand and grease trap prior to discharging to a seepage bed facility which will allow the
storm water to percolate into the existing sub soils.
The proposed storm drainage runoff from the back half of each building will be collected in
gutters and will discharge to the surrounding landscape via downspouts.
The drainage system has been designed to store the 100 -year, I -hour event (1.15 in/hr, time
of concentration = 60 min.). The drainage calculations are shown in Appendix B.
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APPENDIX A
SITE DRAINAGE AREAS
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APPENDIX B
DRAINAGE CALCULATIONS
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THE LAND GROUP, INC. project no: 112142
by: rth
Seepage Bed #1 date: 3/7/2013
Drainage Area #
STORAGE VOLUME REQUIRED (100 Year Storm):
I (based on Zone "A" IDF Curve, 100 -yr Return Period)
Area
Area 2
= -sf
= sf
FArea
= 14,167 sf
EArea
= 0.33 acres
C
=
Infiltration System Characteristics:
STORAGE VOLUME REQUIRED (100 Year Storm):
I (based on Zone "A" IDF Curve, 100 -yr Return Period)
Number of Units
Time
hr
Infiltration Rate =
8.00 in./hr
Length of Seepage Bed =
34.00 ft
Width of Seepage Bed =
15.00 ft
Area of Seepage Bed =
510.00 sf
Depth of Seepage Bed =
4.75 ft
Volume of Seepage Bed =
2422.50 cf
Q perc. =
340.00 cf/hr
OK? OK
Need/Over+10.02 cf
Vs Max = 872 cf .-Maximum Runoff Developed
Vreq= 959 cf .-Maximum Storage Required (+ 10% Sediment Storage)
V prov 40% voids 969 cf Volume Provided
S & G Trap Check
Vault Size
STORAGE VOLUME REQUIRED (100 Year Storm):
I (based on Zone "A" IDF Curve, 100 -yr Return Period)
Number of Units
Time
hr
Time
mina
Time
sec.
Intensity
in./hr)
Q. dev.
(cfs)
V dev.
(cf
V inf.
cf
Vs
cf
0.17
10
600
3.11
0.91
546
57
490
0.25
15
900
2.62
0.77
690
85
605
0.33
20
1,200
2.28
0.67
801
113
688
0.50
30
1,800
1.82
0.53
959
170
789
1
60
3,600
1.15
0.34
1,212
340
872
2
120
7,200
0.66
0.191
1,391
680
711
3
180
10,800
0.48
0.14
1,517
1,020
497
6
360
21,600
0.30
0.09
1,897
2,040
-143
12
720
43,200
0.19
0.06
24031
4,080
-1,677
24
1,4401
86,4001
0.12
0.04
3,035
8,160
-5,125
Vs Max = 872 cf .-Maximum Runoff Developed
Vreq= 959 cf .-Maximum Storage Required (+ 10% Sediment Storage)
V prov 40% voids 969 cf Volume Provided
S & G Trap Check
Vault Size
Oldcastle 1000 gal.
Number of Units
1.00
Baffle Arealunit
6.00 sf
Drain Area
14167.00 sf
Max Flow
0.91 cfs
Max Velocity
0.15 fps
Storm Water Calculations for Tomorrow's Hope Intermediate Care Facility