CC - Drainage ReportKimley»>Horn
Oakwind Estates
Subdivision
Meridian, ID
Prepared By:
Kimley-Horn Associates
950 W Bannock St
Suite 1100
Boise, ID 83702
Contact: Brandon McDougald, P.E.
(801) 915-7842
16551
01 /10/2
v 9 00
Job No. 093893000
January 10, 2021
Kimley>»Horn
GENERAL LOCATION AND DESCRIPTION
This drainage study is being prepared for both Phase 1 and Phase 2 of the Oakwind Estates
Subdivision in Meridian, Idaho. The site is located to the northeast of the intersection of
McDermott Road and McMillan Road. It is bound to the north by a commercial development,
east by Phases 1 and 2 of the Oaks North Subdivision, west by McDermott Road, and south by
McMillan Road. This project consists of approximately 24.36 acres and 185 lots. The site is
located within section 28, Township 4 North, Range 1 West Meridian, Ada County, Idaho.
The proposed development will consist of approximately 212 residential and common lots with
the associated roadways and utilities.
The site currently slopes mostly to the west at a grade of ±0.25-1%. The site is currently a
portion of an undeveloped field used historically for agricultural purposes. The site is in zone
"X", an area determined to be outside the 0.2% annual chance floodplain, according to the
Flood Insurance Rate Map, Map Number 16001C0140J, which bears an effective date of June
19, 2020.
HISTORIC DRAINAGE
Currently, the site is undeveloped, and is bounded by McDermott Rd to the west and McMillan
to the south. This site generally slopes from the southeast to the west at a rate of
approximately 0.25-1'%. In the existing condition it appears that storm water runoff will mostly
infiltrate into the undeveloped ground. Any uncaptured runoff appears to drain to ditches along
McMillan or McDermott where it is eventually conveyed by a culvert under McDermott to the
west. No detention/retention was found to be existing on the current site.
III. DRAINAGE DESIGN CRITERIA
Ada County Highway District (ACHD) requires that new developments provide primary
conveyance for the 100-yr storm event and retention for the 100-yr storm event. The site has
been designed to these standards with detention volumes being determined for the 1-hr 100-yr
event per the ACHD Calculation Sheet for Finding Peak Discharge/Volume Spreadsheet. This
volume was used to design the infiltration beds. The infiltration rate and high groundwater
elevation for this design were taken from a geotechnical report prepared by Materials Testing
and Inspection, Inc. dated July 20, 2018 and numbered 13180977g.
The Rational Method was used in calculating the required retention volume for the site. The
site was delineated into drainage areas based upon the proposed grading and drainage design.
The C-factor was taken to be 0.5 which is the higher end for single family residential listed in
the ACHD "Estimated Runoff Coefficients for Various Surfaces" table. Along the McDermott
Kimley>»Horn
frontage where the residential C-factor did not apply, a composite C-factor was determined
using 0.9 for the roadway and 0.35 for the planted areas.
The required volume and the provided volume of retention for each drainage area has been
calculated and is shown in the appendixes along with all design assumptions.
III. PROPOSED DRAINAGE
The proposed drainage infrastructure will consist of an on -site storm drain system discharging
into an underground infiltration bed for each of the drainage areas.
Prior to releasing water into the on -site underground infiltration beds, the water will be treated
by a sand/oil separator unit per ISPWC SD-606. This treatment unit will be capable of treating
the 25-year event. Since the seepage beds are located in common lots no silt factor was used in
sizing the infiltration beds per the requirements of the ACHD design requirements.
The design infiltration rate was taken to be 8.Oin/hr per the geotechnical report No. B180977g
prepared by Materials Testing & Inspection, Inc. Given this infiltration rate each infiltration bed
will drain in under the required 48 hrs.
Kimley>»Horn
1v�e1»a►111Kl
Seepage Bed - 01
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
0.50
2.92 acres
0.00 cfs
V 5,046
3
Link to: Q•v
QV TR55
5,046 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
38.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
71.1
71.1 ft'/ft
15 Calculate Design Length
L
71
71 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
71
71.0 ft
17 Variable Infiltration Window W
SWW
38.0
38.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
71
79 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9r
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft,
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90% volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_3.xlsm 111012022, 3:36 PM
Version 10.0, May 2018
Seepage Bed - 02
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.50
5.99 acres
0.00 cfs
V 10,351
3
Link to: Q•v
QV TR55
10,351 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
54.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
101.0
101.0 ft,/ft
15 Calculate Design Length
L
102
102 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
102
74.0 ft
17 Variable Infiltration Window W
SWW
54.0
30.0 ft
18 Time to Drain
6.3 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
102
185 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_6.xlsm 1/10/2022, 3:40 PM
Version 10.0, May 2018
Seepage Bed - 03
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.50
1.93 acres
0.00 cfs
V 3,335
Link to: Q•v
QV TR55
3,335 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
17.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
31.9
31.9 ft'/ft
15 Calculate Design Length
L
0
105 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
105
100.0 ft
17 Variable Infiltration Window W
SWW
17.0
17.0 ft
18 Time to Drain
2.6 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
105
100 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_1.xlsm 1/10/2022, 3:32 PM
Version 10.0, May 2018
Seepage Bed - 04
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.50
2.19 acres
0.00 cfs
V 3,784
3
Link to: Q•v
QV TR55
3,784 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
23.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
43.1
43.1 ft'/ft
15 Calculate Design Length
L
0
88 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
88
92.0 ft
17 Variable Infiltration Window W
SWW
23.0
22.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
88
92 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_2.xlsm 1/10/2022, 3:35 PM
Version 10.0, May 2018
Seepage Bed - 05
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
0.50
0.93 acres
0.00 cfs
V 1,607
3
Linkto: Q•v
QV TR55
1,607 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
10.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
18.8
18.8 ft'/ft
15 Calculate Design Length
L
85
86 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
86
ft
17 Variable Infiltration Window W
SWW
10.0
ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
86
ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Bpi onai acorage Lnamoers
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft,
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90% volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_5.xlsm 111012022, 3:39 PM
Version 10.0, May 2018
Seepage Bed - 06
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.50
1.51 acres
0.00 cfs
V 2,609
3
Link to: Q•v
QV TR55
2,609 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
20.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
37.5
37.5 ft'/ft
15 Calculate Design Length
L
70
70 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
70
70.0 ft
17 Variable Infiltration Window W
SWW
20.0
20.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
70
70 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
O
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9r
MW
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft,
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90% volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_4.xlsm 111012022, 3:38 PM
Version 10.0, May 2018
Seepage Bed - 07
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.65
0.63 acres
0.00 cfs
V 1,415
3
Link to: Q•v
QV TR55
1,415 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
10.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
18.8
18.8 ft'/ft
15 Calculate Design Length
L
0
76 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
76
76.0 ft
17 Variable Infiltration Window W
SWW
10.0
10.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
76
76 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_10.xlsm 1/10/2022, 3:45 PM
Version 10.0, May 2018
Seepage Bed - 08
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.65
0.26 acres
0.00 cfs
V 584
3
Link to: Q•v
QV TR55
584 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
10.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
18.8
18.8 ft'/ft
15 Calculate Design Length
L
31
32 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
32
32.0 ft
17 Variable Infiltration Window W
SWW
10.0
10.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
32
32 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_11.xlsm 1/10/2022, 3:46 PM
Version 10.0, May 2018
Seepage Bed - 09
Phase 1
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.65
0.84 acres
0.00 cfs
V 1,887
3
Link to: Q•v
QV TR55
1,887 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
10.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
18.8
18.8 ft'/ft
15 Calculate Design Length
L
100
101 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
101
101.0 ft
17 Variable Infiltration Window W
SWW
10.0
10.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
101
101 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_12.xlsm 1/10/2022, 3:48 PM
Version 10.0, May 2018
Seepage Bed - 10
Phase 2
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.50
2.02 acres
0.00 cfs
V 3,491
3
Link to: Q•v
QV TR55
3,491 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
31.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
58.0
58.0 ft'/ft
15 Calculate Design Length
L
0
61 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
61
80.0 ft
17 Variable Infiltration Window W
SWW
31.0
15.0 ft
18 Time to Drain
3.9 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
61
80 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9W
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft3
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90%volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_7.xlsm 1/10/2022, 3:41 PM
Version 10.0, May 2018
Seepage Bed - 11
Phase 2
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
0.50
1.75 acres
0.00 cfs
V 3,024
Link to: Q•v
QV TR55
3,024 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
15.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
28.2
28.2 ft'/ft
15 Calculate Design Length
L
0
107 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
107
ft
17 Variable Infiltration Window W
SWW
15.0
ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
107
ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Bpi onai acorage Lnamoers
Note: This assumes chambers are organized in a rectangular layout.
1 Type of Chambers
2 Volume to Store
V
3 Installed Chamber Width
Cw
Installed Chamber Depth
Cd
Installed Chamber Height
Ch
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
6 Chamber Storage Volume, With Rock, Per Manuf
7 Total Number of Units Required
8 Area of Infiltration
Aperc
9 Volume Infiltration
Vperc
10 Time to Drain
90% volume in 48-hours minimum
ft2
0 ft3/hr
hours
.3
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_8.xlsm 111012022, 3:43 PM
Version 10.0, May 2018
Seepage Bed - 12
Phase 2
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
NOTE: This worksheet is intended to be a guideline to standardize ACHD checking of drainage calculations and shall not replace the
Engineer's calculation methodology. These calculations shall establish a minimum requirement. The Engineer's methodology must result in
facilities that meet or exceed these calculations in order to be accepted.
Note this spreadsheet pulls information from the "Peak QV" tab
Calculate Post -Development Flows (for pre -development flows, increase number of storage facilities to create new tab)
User input in yellow cells.
1 Project Name Oakwind Estates
2 Enter number of Seepage Beds (25 max)
3 Design Storm
4 Weighted Runoff Coefficient C
5 Area A (Acres)
6 Approved discharge rate (if applicable)
7 Is Seepage Bed in Common Lot? Yes
100
0.50
2.69 acres
0.00 cfs
V 4,648
3
Link to: Q•v
QV TR55
4,648 ft' 0%Sediment
8 Set Total Design Width of All Drain Rock
W
27.0 ft
9 Set Total Design Depth of All Drain Rock
D
3.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock
Voids
0.4
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max)
Perc
8.00 in/hr
12 Size of WQ Perf Pipe (Pert 180°)
Dia pipe
18 in
13 Size of Overflow Perf Pipe (Perfs 360°), REQD if Q100>3.3 cfs
in
14 Calculate Total Storage per Foot
Spf
50.6
50.6 ft'/ft
15 Calculate Design Length
L
0
92 ft
Override Value Required for Chambers
16 Variable Infiltration Window L
SWL
92
92.0 ft
17 Variable Infiltration Window W
SWW
27.0
27.0 ft
18 Time to Drain
2.5 hours
90%volume in 48-hours minimum
19 Length of WQ & Overflow Perf Pipes
92
92 ft
20 Perf Pipe Checks. Qperf>= Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers 9
Note: This assumes chambers are organized in a rectangular layout.
1-StormTech,
1 Type of Chambers
SC740
2 Volume to Store
V
0 ft,
3 Installed Chamber Width
Cw
4.25 ft
Installed Chamber Depth
Cd
2.50 ft
Installed Chamber Height
Ch
7.12 ft
4 Chamber Void Factor
5 Chamber Storage Volume, Without Rock, Per Manuf
45.90 ft3
6 Chamber Storage Volume, With Rock, Per Manuf
74.90 ft3
7 Total Number of Units Required
0 ea
8 Area of Infiltration
Aperc
ftz
9 Volume Infiltration
Vperc
0 ft3/hr
10 Time to Drain
hours
90% volume in 48-hours minimum
K:\BOI_Civil\093893000 Oakwind BB Living\_Project Files\Eng\Drainage\ACHD Calcs\ACHD_SD_CALCS_9.xlsm 111012022, 3:44 PM
Version 10.0, May 2018
APN:
APN.
SO428325610
SO428325460
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DRAINAGE AREA DESIGNATION 7
DRAINAGE AREA (AC) ###
DRAINAGE AREA BOUNDARY
811
Knanrw.r. bebw.
Call before yo„ dig.
— — — —
CALL 2 BUSINESS DAYS
IN ADVANCE BEFORE
YOU DIG, GRADE, OR
EXCAVATE FOR THE
MARKING OF
_
UNDERGROUND
—
—' M EMBER UTILITIES
6
GRAPHIC SCALE IN FEET
0 30 60 120 NORTH
d
0
OAKWIND ESTATES
PROPOSED DRAINAGE AREA MAP
MERIDIAN, ID
a
Kim Fey)))Horn z
CQ 2022 KIMLEY—HORN AND ASSOCIATES, INC. m
950 Bannock Street, Suite 1100 oo
Boise, Idaho 83702 208 297-2885
0
FOR REVIEW ONLY
NOT FOR
CONSTRUCTION
Kimley»)Horn
DESIGNED DRAWN C
MR BKG
SCALE (H): 1"=60'
SCALE (V): N/A
1
1
National Flood Hazard Layer FIRMette .. FEMA
116o28'38"W 43o39'13"N
-- 1.17,VVV
0 250 500 1,000 1,500 2,000
Basemap: USGS National Map: Orthoimagery. Data refreshed October, 2020
Legend
SEE FIS REPORT FOR DETAILED LEGEND AND INDEX MAP FOR FIRM PANEL LAYOUT
Without Base Flood Elevation (BFE)
Zone A, V, A99
SPECIAL FLOOD
With BFE or Depth Zone AE, Ao, AH. VE. AR
HAZARD AREAS
Regulatory Floodway
0.2% Annual Chance Flood Hazard, Areas
of 1% annual chance flood with average
depth less than one foot or with drainage
areas of less than one square mile Zonex
Future " Conditions 1% Annual Chance Flood Hazard Zone
Area with Reduced Flood Risk due to
OTHER AREAS OF Levee. See Notes. Zone
FLOOD HAZARD Area with Flood Risk due to Levee zone D
NO SCREEN Area of Minimal Flood Hazard Zone
Q Effective LOMRs
OTHER AREAS Area of Undetermined Flood Hazard Zone D
GENERAL - — - - Channel, Culvert, or Storm Sewer
STRUCTURES I I I I I I I Levee, Dike, or Floodwall
Cross Sections with 1% Annual Chance
17•5 Water Surface Elevation
a - - - Coastal Transact
—5f5— Base Flood Elevation Line (BFE)
Limit of Study
Jurisdiction Boundary
— --- Coastal Transact Baseline
OTHER _ Profile Baseline
FEATURES Hydrographic Feature
Digital Data Available N
No Digital Data Available
MAP PANELS Unmapped
QThe pin displayed on the map is an approximate
point selected by the user and does not represent
an authoritative property location.
This map complies with FEMA's standards for the use of
digital flood maps if it is not void as described below.
The basemap shown complies with FEMA's basemap
accuracy standards
The flood hazard information is derived directly from the
authoritative NFHL web services provided by FEMA. This map
was exported on 1/11/2022 at 10:34 AM and does not
reflect changes or amendments subsequent to this date and
time. The NFHL and effective information may change or
become superseded by new data over time.
This map image is void if the one or more of the following map
elements do not appear: basemap imagery, flood zone labels,
legend, scale bar, map creation date, community identifiers,
FIRM panel number, and FIRM effective date. Map images for
unmapped and unmodernized areas cannot be used for
regulatory purposes.