HomeMy WebLinkAboutCC - Storm Drainage Calcs DRAINAGE CALCULATIONS
FOR
TANNER CREEK SUBDIVISION N0.1
MERIDIAN, IDAHO
November 5, 2024
ENGINEERING SOLUTIONS, LLP
1029 N. Rosario Street, Suite 100
Meridian, Idaho 83642
(208) 938 -0980
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Job Number: 231201
Areas 1, IA and 2 will be picked up in drop inlets and piped into three 1000 -
gallon sand and grease traps. Areas 3 and 4 will be picked up in drop inlets and
piped into a manhole. From the manhole it is piped to the sand and grease traps
where it splits into three pipes to the seepage bed. Three 18" PVC pipes goes 5'
into seepage bed 1.1. Three 18" top only perforated pipes extend through the
seepage bed. The seepage bed has 1.5' of filter sand below it. The seepage bed is
designed to have 3' of separation from high groundwater.
Areas 5 and 6 will be picked up in drop inlets and piped into a 1000 - gallon sand
and grease trap. An 18"pipe from the sand and grease trap goes 5' into seepage
bed 1.2. An 18" top only perforated pipe extends through the seepage bed. The
seepage bed has 1.5' of filter sand below it. The seepage bed is designed to have
3' of separation from high groundwater.
Areas 7, 8 and 8A will be picked up in drop inlets and piped into two 1000 -
gallon sand and grease traps. Areas 9 and 10 will be picked up in future drop
inlets and piped into the sand and grease traps. Two 18" PVC pipes go 5' into
seepage bed 1.3. Two 18" top only perforated pipes extend through the seepage
bed. The seepage bed has 1.5' of filter sand below it. The seepage bed is
designed to have 3' of separation from high groundwater (groundwater was not
encountered).
Areas 11 and 12 will be picked up in drop inlets and piped into a 1000 - gallon
sand and grease trap. An 18" PVC pipe goes 5' into seepage bed 1.4. An 18" top
only perforated pipe extends through the seepage bed. The seepage bed has 1.5'
of filter sand below it. The seepage bed is designed to have 3' of separation from
high groundwater (groundwater was not encountered).
Seepage Beds
The seepage beds are sized for the 100-year storm per ACHD Stormwater
Design Spreadsheet. The seepage beds use clean drain rock wrapped in filter
fabric to facilitate drainage, top half perforated pipes, perforated pipes and
1.5' of sand underneath the clean drain rock. The seepage beds also contain
a monitoring well inside the beds and one outside the beds. The seepage
beds were sized using a percolation rate of 1"/hr through the bottom of the
beds. The seepage bed drains 90% of the 100-year storm within 48 hours.
The beds were designed to have a minimum of 3' of separation from high
groundwater based on the geotechnical report provided by Atlas Technical
Consultants, LLC.
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ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method
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.
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 Tanner Creek Areas 1,3A,2,3,&4
2 Is area drainage basin map provided? YES
(map must be included with stormwater calculations)
3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100
4 Enter number of storage facilities(25 max)
Click to Show More Subbasins ❑
Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin
1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10
5 Area of Drainage Subbasin(SF or Acres) Acres 1.57 1.89 0.35 0.53 0.61
Acres 4.95
6 Determine the Weighted Runoff Coefficient(C) 0.50 0.75 0.50 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.60
7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 user Calculate
min 10 Min. Estimated Runoff Coefficients for Various Surface
Type of Surface Runoff Coefficients"t
Business
Downtown areas 0.70-0.95
Hydraulic Urban neighborhoods 0.50-0.70
Radius FlowLFlowTime
Residential
Intercept A/Wet Velocity V Single Family 0.35-0.50
Multi-family 0.60-0.75
ID Pipe Size(in) Slope(ft/ft) Coeff. Length Manning n Perm (fps) Residential(rural) 0.25-0.40
Segment 1:Pipe Flow Apartment Dwelling Areas 0.70
a Industrial and Commercial
Light areas 0.80
Segment 2:Gutter Shallow Concentrated Flow Heavy areas 0.
90
Se
g Parks,Cemeteries 0.10-0.25
b 0.004 0.619 876 1.3 11.1 Playgrounds 0.20-0.35
Railroad yard areas 0.20-0.40
Segment 3:Overland Sheet Flow By TR-55,<300-ft
c 0.020 60 0.240 3.9 15.5
Computed Tc= 26.6
User-Entered Tc= 26.6
8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.58 in r
y Calculate the Post-Development peak discharge(QPeak) C peak 4.66 cfs
10 Calculate total runoff vol(V)(for sizing primary storage) V 10,187 ft
V=Ci(Tc=60)Ax3600
11 Calculate Volume of Runoff Reduction Vrr
Enter Percentile Storm 1(95th percentile=0.60 in) 95th 0.60 in
Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) V,r 6,367 ft'
12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs
13 Volume Summary Unimproved areas 0.10-0.30
Surface Storage:Basin Streets
Basin Forebay V 1,019 ft Asphalt 0.95
Concrete 0.95
Primary Treatment/Storage Basin V 9,168 ft' Brick 0.95
Subsurface Storage Roofs 0.95
Gravel
Volume Without Sediment Factor(See BMP 20 Tab) V 10,187 ft'
Fields:Sandy soil Soil Soil Type
Slope A B C D
Flat:0-2% 0.04 0.07 0.11 0.
Average:2-6% 0.09 0.12 0.15 0.
Steep:>6% 0.13 0.18 0.23 0.
Adapted from ASCE
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.1-1A-2-3-4.xlsm 11/5/2024,2:54 PM
Version 10.S,November 2018
ACHD Calculation Sheet for Sand/Grease Traps
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.
User input in yellow cells.
1 Project Name Tanner Creek Areas 1,1A,2,3,&4
2 Enter number of Sand/Grease Traps(25 max) 1
Number of Peak Flow Baffle Throat Velocity Is the
[71000G
Spacing width Area(ft2) 0.5 fps Velocity
S/G Traps Q-cfs inch inch max. ok?
3 4.66 20 48 20.00 0.23
Reference for Throat widths(inch)
ADS
Boise Lar-ken WQU,
Vault BMP 16
1000 G 48.0 50.5 n/a
1500 G 60.0 61.5 n/a
WQU 1000 n/a n/a 60
WQU 1500 n/a n/a 60
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.1-1A-2-3-4.x1sm 11/18/2024,2:07 PM
Version 10.0, May 2018
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 Q,V"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 Tanner Creek Areas 1,1A,2,3,&4
2 Enter number of Seepage Beds(25 max) 1
3 Design Storm 100
4 Weighted Runoff Coefficient C 0.60 Link to: Qv
5 Area A(Acres) 4.95 acres QV TR55
6 Approved discharge rate(if applicable) 0.00 cfs lI
7 Is Seepage Bed in Common Lot? Yes V 10,187 ft3 0%Sediment
8 Set Total Design Width of All Drain Rock W 40.0 ft
9 Set Total Design Depth of All Drain Rock D 5.5 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 1801) Dia pipe 18 in
13 Size of Overflow Perf Pipe(Perfs 3601),READ if Q100>3.3 cfs in
14 Calculate Total Storage per Foot Spf 114.8 ft3/ft
15 Calculate Design Length L 89 ft
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 89 ft
17 Variable Infiltration Window W SWW 40.0 ft
18 Time to Drain 3.9 hours
90%volume in 48-hours minimum
19 Length of WQ&Overflow Perf Pipes 89 ft
20 Perf Pipe Checks.Qperf>=Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage chambers
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 ft'/Unit
6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit
7 Total Number of Units Required 0 ea
8 Area of Infiltration Aperc ft2
9 Volume Infiltration Vperc 0 ft3/hr
10 Time to Drain hours
90%volume in 48-hours minimum
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.1-1A-2-3-4.xlsm 11/5/2024,2:55 PM
Version 10.0,May 2018
ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method
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.
for Peak` t
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 Tanner Creek Areas 5&6
2 Is area drainage basin map provided? YES
(map must be included with stormwater calculations)
3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100
4 Enter number of storage facilities(25 max)
Click to Show More Subbasins ❑
Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin
1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10
5 Area of Drainage Subbasin(SF or Acres) Acres 1.22 0.26
Acres 1.48
6 Determine the Weighted Runoff Coefficient(C) 0.75 0.75
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.75
7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate
min 10 Min. Estimated Runoff Coefficients for Various Surface
Type of Surface Runoff Coefficients"t
Business
Downtown areas 0.70-0.95
Hydraulic Urban neighborhoods 0.50-0.70
Radius Flow Residential
Intercept A/Wet Velocity V Flow Time Single Family 0.35-0.50
ID Pipe Size(in) Slope(ft/ft) Coeff. Length Manning n Perm (fps) (min) Multi-family 0.60-0.75Residential rural 0.25-0.40
Segment 1:Pipe Flow Apartment Dwelling Areas 0.70
a Industrial and Commercial
Light areas 0.80
Segment 2:Gutter Shallow Concentrated Flow Heavy areas 0.
90
Se
g Parks,Cemeteries 0.10-0.25
b 0.005 0.619 216 1.5 2.5 Playgrounds 0.20-0.35
Railroad yard areas 0.20-0.40
Segment 3:Overland Sheet Flow By TR-55,<300-ft
c 0.020 75 0.240 4.1 18.5
Computed Tc= 21.0
User-Entered Tc= 21.0
8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.81 in r
y Calculate the Post-Development peak discharge(QPeak) Qpeak 2.01 cfs
10 Calculate total runoff vol(V)(for sizing primary storage) V 3,836 ft
V=Ci(Tc=60)Ax3600
11 Calculate Volume of Runoff Reduction Vrr
Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in
Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 2,398 ft,
12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs
13 Volume Summary Unimproved areas 0.10-0.30
Surface Storage:Basin Streets
Basin Forebay V 384 ft Asphalt 0.95
Concrete 0.95
Primary Treatment/Storage Basin V 3,453 W Brick 0.95
Subsurface Storage Roofs 0.95
Volume Without Sediment Factor(See BMP 20 Tab) V 3,836 ft' Gravel Fields:Sandy soil Soil Soil Type
Slope A B C D
Flat:0-2% 0.04 0.07 0.11 0.
Average:2-6% 0.09 0.12 0.15 0.
Steep:>6% 0.13 0.18 0.23 0.
Adapted from ASCE
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.5-6.xlsm 11/5/2024,3:03 PM
Version 10.5,November 2018
ACHD Calculation Sheet for Sand/Grease Traps
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.
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name Tanner Creek Areas 5&6
2 Enter number of Sand/Grease Traps(25 max) 1
Number of Peak Flow Baffle Throat Velocity Q0k?
Vault Size Spacing width Area(ft2) 0.5 fps V
S/G Traps Q-cfs inch inch max.
1000 G 1 2.01 20 48 6.67 0.30
Reference for Throat widths(inch)
Boise ADS
Vault Lar-ken WQU,
BMP 16
1000 G 48.0 50.5 n/a
1500 G 60.0 61.5 n/a
WQU 1000 n/a n/a 60
WQU1500 n/a n/a 60
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.5-6.xlsm 11/5/2024,3:04 PM
Version 10.0, May 2018
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 Tanner Creek Areas 5&6
2 Enter number of Seepage Beds(25 max) 1
3 Design Storm 100
4 Weighted Runoff Coefficient C 0.75 Link to: Lav
QV TR55
5 Area A(Acres) 1.48 acres
6 Approved discharge rate(if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? Yes V 3,836 ft 3 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 5.5 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(Perf 1800) Dia pipe 18 in
13 Size of Overflow Perf Pipe(Perfs 3601),REQD if Q100>3.3 cfs in
14 Calculate Total Storage per Foot Spf 28.8 ft3/ft
15 Calculate Design Length L 133 ft
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 133 ft
17 Variable Infiltration Window W SWW 10.0 ft
18 Time to Drain 3.9 hours
90%volume in 48-hours minimum
19 Length of WQ&Overflow Perf Pipes 133 ft
20 Perf Pipe Checks.Qperf>=Qpeak;
where Qperf=CdxAxV(2x,gxH)
Optional Storage Chambers
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/Unit
6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit
7 Total Number of Units Required 0 ea
8 Area of Infiltration Aperc ft2
9 Volume Infiltration Vperc 0 ft3/hr
10 Time to Drain hours
90%volume in 48-hours minimum
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.5-6.xlsm 11/5/2024,3:04 PM
Version 10.0,May 2018
ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method
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.
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 Tanner Creek Areas 7,8,8A,9&10
2 Is area drainage basin map provided? YES
(map must be included with stormwater calculations)
3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100
4 Enter number of storage facilities(25 max)
Click to Show More Subbasins ❑
Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin
1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10
5 Area of Drainage Subbasin(SF or Acres) Acres 0.43 1.96 0.87 1.40 0.67
Acres 5.33
6 Determine the Weighted Runoff Coefficient(C) 0.75 0.50 0.75 0.75 0.75
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.66
7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 User Calculate
min to Min. Estimated Runoff Coefficients for Various Surface
Type of Surface Runoff Coefficients"I
Business
Downtown areas 0.70-0.95
Hydraulic Urban neighborhoods 0.50-0.70
Radius Flow Residential
Intercept A/Wet Velocity V Flow Time single Family 0.35-0.50
ID Pipe Size(in) Slope(ft ft) Coeff. Length Manning n Perm (fps) (min) Multi-family 0.60-0.75
Residential rural 0.25-0.40
Segment 1:Pipe Flow Apartment Dwelling Areas 0.70
a Industrial and Commercial
Light areas 0.80
Heavy areas 0.90
Segment 2:Gutter Shallow Concentrated Flow Parks,Cemeteries 0.10-0.25
b 0.005 0.619 915 1.5 10.3 Playgrounds 0.20-0.35
Railroad yard areas 0.20-0.40
Segment 3:Overland Sheet Flow By TR-55,<300-ft
c 0.020 68 0.240 4.0 17.1
Computed Tc= 27.4
User-Entered Tc= 27.4
8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.58 in r
y Calculate the Post-Development peak discharge(QPeak) Qpeak 5.54 cfs
10 Calculate total runoff vol(V)(for sizing primary storage) V 12,122 ft
V=Ci(Tc=60)Ax3600
11 Calculate Volume of Runoff Reduction Vrr
Enter Percentile Storm 1(95th percentile=0.60 in) 95th 0.60 in
Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 7,576 ft'
12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs
13 Volume Summary Unimproved areas 0.10-0.30
Surface Storage:Basin Streets
Basin Forebay V 1,212 ft' Asphalt 0.95
Concrete 0.95
Primary Treatment/Storage Basin V 10,910 ft' Brick 0.95
Subsurface Storage Roofs 0.95
Volume Without Sediment Factor(See BMP 20 Tab) V 12,122 ft' Gravel 0.75
Fields:Sandy soil Soil Type
Slope A B C D
Flat:0-2% 0.04 0.07 0.11 0.
Average:2-6% 0.09 0.12 0.15 0.
Steep:>6% 0.13 0.18 0.23 0.
Adapted from ASCE
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.7-8-8A-9-10.xlsm 11/5/2024,3:05 PM
Version 10.5,November 2018
ACHD Calculation Sheet for Sand/Grease Traps
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.
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name Tanner Creek Areas 7,8,8A,9&10
2 Enter number of Sand/Grease Traps(25 max) 1
Number of Peak Flow Baffle Throat Velocity Is the
F1000
S/G Traps Q-cfs Spacing width Area(ft2) 0.5 fps Velocity
inch inch max. ok?
2 5.54 20 48 13.33 0.42
Reference for Throat widths(inch)
ADS
Boise Lar-ken WQU,
Vault BMP 16
1000 G 48.0 50.5 n/a
1500 G 60.0 61.5 n/a
WQU1000 n/a n/a 60
WQU1500 n/a n/a 60
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.7-8-8A-9-10.xlsm 11/5/2024,3:05 PM
Version 10.0, May 2018
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 Q,V"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 Tanner Creek Areas 7,8,8A,9&10
2 Enter number of Seepage Beds(25 max) 1
3 Design Storm 100
4 Weighted Runoff Coefficient C 0.66 Link to: Qv
QV TR55
S Area A(Acres) 5.33 acres
6 Approved discharge rate(if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? Yes V 12,122 ft, 0%Sediment
8 Set Total Design Width of All Drain Rock W 30.0 ft
9 Set Total Design Depth of All Drain Rock D 3.2 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 1801) Dia pipe 18 in
13 Size of Overflow Perf Pipe(Perfs 3600),READ if Q100>3.3 cfs in
14 Calculate Total Storage per Foot Spf 58.6 ft3/ft
15 Calculate Design Length L 207 ft
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 207 ft
17 Variable Infiltration Window W SWW 30.0 ft
18 Time to Drain 2.6 hours
90%volume in 48-hours minimum
19 Length of WQ&Overflow Perf Pipes 207 ft
20 Perf Pipe Checks.Qperf>=Qpeak;
where Qperf=CdxAxV(2xgxH)
_-- _ - -__-—- __----
Optional Storage Chambers
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/Unit
6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit
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
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.7-8-8A-9-10.xlsm 11/5/2024,3:05 PM
Version 10.0,May 2018
ACHD Calculation Sheet for Finding Peak Discharge/Volume-Rational Method
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.
t thod calculated for post-devefopment
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 Tanner Creek Areas 11&12
2 Is area drainage basin map provided? YES
(map must be included with stormwater calculations)
3 Enter Design Storm(100-Year or 25-Year With 100-Year Flood Route) 100
4 Enter number of storage facilities(25 max)
Click to Show More Subbasins ❑
Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin Subbasin
1 Subbasin 2 3 4 5 Subbasin 6 7 8 9 10
5 Area of Drainage Subbasin(SF or Acres) Acres 1.20 1.66
Acres 2.86
6 Determine the Weighted Runoff Coefficient(C) 0.50 0.75
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg1 0.65
7 Calculate Overland Flow Time of Concentration in Minutes(Tc)or use default 10 user Calculate
min
10 Min. Estimated Runoff Coefficients for Various Surface
Type of Surface Runoff Coefficients"I
Business
Downtown areas 0.70-0.95
Hydraulic Urban neighborhoods 0.50-0.70
Radius FlowLFlowTime
Residential
Intercept A/Wet Velocity V Single Family 0.35-0.50
Multi-family 0.60-0.75
ID Pipe Size(in) Slope(ft/ft) Coeff. Length Manning n Perm (fps) Residential(rural) 0.25-0.40
Segment 1:Pipe Flow Apartment Dwelling Areas 0.70
a Industrial and Commercial
Light areas 0.80
Heavy areas 0.90
Segment 2:Gutter Shallow Concentrated Flow
Parks,Cemeteries 0.1010
-0.25
b 0.004 0.619 635 1.3 1 Playgrounds 0.20-0.35
Railroad yard areas 0.20-0.40
Segment 3:Overland Sheet Flow By TR-55,<300-ft
c 0.020 68 0.240 4.0 17.1
Computed Tc= 25.4
User-Entered Tc= 25.4
8 Determine the average rainfall intensity(i)from IDF Curve based on Tc i 1.58 in r
y Calculate the Post-Development peak discharge(QPeak) Qpeak 2.92 cfs
10 Calculate total runoff vol(V)(for sizing primary storage) V 6,376 ft
V=Ci(Tc=60)Ax3600
11 Calculate Volume of Runoff Reduction Vrr
Enter Percentile Storm I(95th percentile=0.60 in) 95th 0.60 in
Enter Runoff Reduction Vol(95th Percentile=0.60-in x Area x C) Vrr 3,985 ft'
12 Detention:Approved Discharge Rate to Surface Waters(if applicable) cfs
13 Volume Summary Unimproved areas 0.10-0.30
Surface Storage:Basin Streets
Basin Forebay V 638 fe Asphalt 0.95
Concrete 0.95
Primary Treatment/Storage Basin V 5,739 ft' Brick 0.95
Subsurface Storage Roofs 0.95
Volume Without Sediment Factor(See BMP 20 Tab) V 6,376 ft' Gravel 0.75
Fields:Sandy soil Soil Type
Slope A B C D
Flat:0-2% 0.04 0.07 0.11 0.
Average:2-6% 0.09 0.12 0.15 0.
Steep:>6% 0.13 0.18 0.23 0.
Adapted from ASCE
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.11-12.xlsm 11/5/2024,3:06 PM
Version 10.5,November 2018
ACHD Calculation Sheet for Sand/Grease Traps
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.
User input in yellow cells.
1 Project Name Tanner Creek Areas 11&12
2 Enter number of Sand/Grease Traps(25 max) 1
Number of Peak Flow Baffle Throat Velocity Is the
[10
ault Size Spacing width Area(ft2) 0.5 fps Velocity
S/G Traps Q-cfs inch inch max. ok?
0 GG 1 2.92 20 48 6.67 0.44
Reference for Throat widths(inch)
ADS
Boise Lar-ken WQU,
Vault BMP 16
1000 G 48.0 50.5 n/a
1500 G 60.0 61.5 n/a
WQU1000 n/a n/a 60
WQU1500 n/a n/a 60
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.11-12.xlsm 11/5/2024,3:06 PM
Version 10.0, May 2018
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 Tanner Creek Areas 11&12
2 Enter number of Seepage Beds(25 max) 1
3 Design Storm 100
4 Weighted Runoff Coefficient C 0.65 Link to: LCLV
QV TR55
5 Area A(Acres) 2.86 acres
6 Approved discharge rate(if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? Yes V 6,376 ft3 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 4.5 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 1801) Dia pipe 18 in
13 Size of Overflow Perf Pipe(Perfs 3600),REQD if Q100>3.3 cfs in
14 Calculate Total Storage per Foot Spf 37.2 ft3/ft
15 Calculate Design Length L 172 ft
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 172 ft
17 Variable Infiltration Window W SWW 15.0 ft
18 Time to Drain 3.3 hours
90%volume in 48-hours minimum
19 Length of WQ&Overflow Perf Pipes 172 ft
20 Perf Pipe Checks.Qperf>=Qpeak;
where Qperf=CdxAxV(2xgxH)
Optional Storage Chambers
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/Unit
6 Chamber Storage Volume,With Rock,Per Manuf 74.90 ft3/Unit
7 Total Number of Units Required 0 ea
8 Area of Infiltration Aperc ft2
9 Volume Infiltration Vperc 0 ft3/hr
10 Time to Drain hours
90%volume in 48-hours minimum
\\ES-1\Projects\2023\231201\Calcs\ACHD_SD_CALCS_Area No.11-12.xlsm 11/5/2024,3:07 PM
Version 10.0,May 2018
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ENGINEER
REVISIONS ENGINEER SCALE 1 -60
T.P.#23 T.P.#24 oNAL TANNERCREEK
_ ENGINEERING SOLUTIONS LLP S� F� DWG.DATE 11 14 24
GND=2307.65 GND=2609.42
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I GND WTR 25s7.7 i_ ... .. GND WTR N/A Joshua H. Mann, P.E,
1029 N. ROSARIO ST., Ste. 100 a 0
SUBDIViSION NO. 1 PROJ. N®.
231201
GND-2s;;o Ar
MERIDIAN, IDAHO 83642 203UTIONSLLP
SE 1, SECTION 13, T.4N., RAW., B.M. SHEET 1 OF 1
GND WTR=2602.90± Phone (208) 938-0980 MERIDIAN, ADA COUNTY, IDAHO
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E-Mail: or �`josh m®en m@engsol.org 9 gTE OF�p@'���' 1029 N. ROSA IO STIR., SUITE 100
-•- ......... THIS DRAINING OR FILE CONTAINS INFORMATION OWNED BY ENGINEERING SOLUTIONS,LLP AND WILL y(� MERIDIAN,I®IAN, IDAHO 83642
- - - - T - - - Vi►. DRAINAO-E PLAN
BE GOVERNED ONLY BY ENGINEERING SOLUTIONS. THESE CONTENTS MAY NOT BE REPRODUCED OR Phone (208) 938-0980 Fox (208) 938-0941
MAY ONLY BE USED WITH THE PRIOR WRITTEN CONSENT OF ENGINEERING SOLUTIONS,LLP /231201-DRN.DING