HomeMy WebLinkAboutStorm Drainage Calcs V1Southridge South Subdivision – Phase 1
Meridian, Idaho
Storm Drain Management & Engineering Drainage Report
Developer
Challenger Development
Meridian, ID 83642
Engineer
The Land Group, Inc.
462 East Shore Drive, Suite 100
Eagle, Idaho 83616
Contact: Jason Densmer, PE
Ph: 208-939-4041
October 26, 2021
TLG Project No. 121027
10/27/2021
12/06/21
FP-2021-0059
Southridge South Subdivision – Phase 1
Meridian, ID
Storm Water Management Report
Report Purpose & Site Description
The purpose of this report is to evaluate and document the post-development storm drain characteristics
of the Southridge South Subdivision – Phase 1 project. This report analyzes the storm drainage conditions
and provides calculations confirming the adequacy of proposed storm drain facilities to meet the project
needs.
The proposed Southridge South Subdivision – Phase 1 project is located located south of Overland Road,
between Linder Rd and Ten Mile, within the City of Meridian, Idaho. The proposed improvements consist
of single family homes with associated site improvements including new access roads, landscaping and
underground utilities.
Geotechnical conditions at the site were evaluated by Site Consulting, LLC and their findings are attached
as Appendix C. The site geotechnical evaluation provides guidance on design and project construction
considerations. Relative to storm drainage systems, recommendations for groundwater and soil
infiltration rates are provided. The geotechnical engineer’s recommendations have been incorporated to
the proposed design and systems.
Proposed Systems
Appendix A provides an overview of the proposed drainage basins.
Storm Drainage Routing & Treatment
Within each drainage basin, stormwater runoff is collected from roadways that are sloped to the gutters
along the road edges, which then transport the collected drainage to catch basins. Once inside the system,
stormwater flows through a drainage piping network to sand & grease traps which remove heavy
sediment and light oils prior to discharge into underground seepage beds. The seepage bed provides final
treatment with an 18-inch layer of ASTM C33 filter sand.
Peak Rate of Discharge and Storage Volume
The peak rate of discharge for the roadway drainage systems were calculated using the Ada County
Highway District’s published spreadsheets.
Calculation worksheets for peak flow and required storage volume in each drainage basin are provided in
Appendix B.
12/06/21
FP-2021-0059
Southridge South Subdivision – Phase 1
Meridian, ID
Storm Water Management Report
Appendix A
Site Drainage Areas
12/06/21
FP-2021-0059
EP EP EP
EP
EP
EP
EP
O
O
O O
O O
O
O
O
O
O
O
O
SD
SD
SD
SD
EP EP EP
EP
EP
EP
SD
SD
S
D
R/W
R/W
R/W R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
G G
G
G
G
G G
G
G
G
G G
G
G G G
G
G
Southridge South Subdivision – Phase 1
Meridian, ID
Storm Water Management Report
Appendix B
Drainage Calculations
12/06/21
FP-2021-0059
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
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) 8
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 8,477
Acres 0.19
6 Determine the Weighted Runoff Coefficient (C) 0.90
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.90
7
I100, TC<=60
8 i 2.58 in/hr
9 Q
peak 0.45 cfs
10 V 605 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 378 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 61 ft
3
Primary Treatment/Storage Basin V 545 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 605 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
2
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 47,575 44,282
Acres 2.11
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 2.72 cfs
10 V 3,644 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 2,277 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 364 ft
3
Primary Treatment/Storage Basin V 3,280 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 3,644 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 2
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
3
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 76,980 58,074
Acres 3.10
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 4.00 cfs
10 V 5,358 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 3,348 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 536 ft
3
Primary Treatment/Storage Basin V 4,822 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 5,358 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 3
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 20,644 19,931
Acres 0.93
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 1.20 cfs
10 V 1,610 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 1,006 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 161 ft
3
Primary Treatment/Storage Basin V 1,449 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 1,610 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 4
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
5
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 42,144 36,621
Acres 1.81
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 2.33 cfs
10 V 3,125 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 1,953 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 312 ft
3
Primary Treatment/Storage Basin V 2,812 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 3,125 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 5
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 57,020 48,874
Acres 2.43
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 3.14 cfs
10 V 4,201 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 2,625 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 420 ft
3
Primary Treatment/Storage Basin V 3,781 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 4,201 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 6
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
7
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 14,513 2,889
Acres 0.40
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 0.52 cfs
10 V 690 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 431 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 69 ft
3
Primary Treatment/Storage Basin V 621 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 690 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 7
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Peak Discharge Rate using the Rational Method calculated for post-development
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
8
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
Click to Show More Subbasins
Subbasin
1 Subbasin 2
Subbasin
3
Subbasin
4
Subbasin
5 Subbasin 6
Subbasin
7
Subbasin
8
Subbasin
9
Subbasin
10
5 Area of Drainage Subbasin (SF or Acres) SF 2,897 2,912
Acres 0.13
6 Determine the Weighted Runoff Coefficient (C) 0.50 0.50
C=[(C1xA1)+(C2xA2)+(CnxAn)]/A Weighted Avg 0.50
7
I100, TC<=60
8 i 2.58 in/hr
9 Qpeak 0.17 cfs
10 V 230 ft
3
V = Ci (Tc=60)Ax3600
11
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) V
rr 144 ft
3
12 Detention: Approved Discharge Rate to Surface Waters (if applicable) cfs
13 Volume Summary
Surface Storage: Basin
Basin Forebay V 23 ft
3
Primary Treatment/Storage Basin V 207 ft
3
Subsurface Storage
Volume Without Sediment Factor (See BMP 20 Tab) V 230 ft
3
Calculate total runoff vol (V) (for sizing primary storage)
Calculate Volume of Runoff Reduction Vrr
Determine the average rainfall intensity (i) from IDF Curve based on Tc
Calculate the Post-Development peak discharge (QPeak)
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.
Southridge South Phase 1, Facility 8
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
Steps for Sizing Basins: Size for forebay and print then size for primary storage/treatment basin.
User input in yellow cells.
1 Project Name
2 Enter number of Basins (25 max) 3
3 Number of Cells (Forebay+Primary=2, Primary Only=1) 1
4 Design Storm 100 'Q,V' Link to:
5 Weighted Runoff Coefficient C 0.90
6 Area A (Acres) 0.19 acres
7 Approved Discharge Rate (if applicable) 0.00 cfs
8 V 605 ft3
Toggle between Forebay and Primary Basin, enter data and print for each
Forebay
9 Select Forebay Shape
10 Width of Forebay Bottom W 33.0 ft
11 Length of Forebay Bottom L 40.0 ft
12 Side Slopes (H:1) H:1 4.00
13 Enter Bottom Elevation 2684.88 ft
14 Enter Top Bank Elevation 2686.38 ft
15 Enter Water Surface Elevation (WSE) 2685.88 ft
16 Distance Between Forebay and Primary Basin (blank if na) 0.00 ft
17 Enter Elevation Berm 0.00 ft
18 Enter High Groundwater Elevation 0.00 ft
19 Min. Freeboard Requirement 0.50
20 Freeboard Provided 0.50
21 Infiltration Area for Forebay Infiltration? 6.00 in/hr Note: infiltration required if
Design Infiltration Rate, Enter 0 for no infiltration bottom slope<1% or 0 outflow
22 Infiltration Area for Forebay ASand 330 ft2
Enter 0 for no infiltration
23 Adjusted Storage Required
i total Q
Runoff
Vol
Perc Vol
Pre-Dev
Discharge
Total
Discharge
Max Vol
Reqd
Min Hr in/hr cfs ft3 ft3 ft3 ft3 ft3
60 1.00 0.96 0.17 605 165 0 165 440
24 Depth-Storage Relationship:
2684.88 2684.88 4.000 33.0 40.0 1,320 0.00 0
2684.88 4.000 33.0 40.0 1,320 0.00 0
2685.88 4.000 41.0 48.0 1,968 0.00 1,644
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
1.00 ft depth for storage STORAGE OK
25 Does forebay have capacity? YES
26 Time to drain forebay 3.3 hours
90% volume in 48-hours minimum OK
Storm Duration
Saved
Stage (ft) New Stage (ft)
Steps for Sizing Basins: Size for forebay and print then size for primary storage/treatment basin.
User input in yellow cells.
1 Project Name
2
2 Enter number of Basins (25 max) 3
3 Number of Cells (Forebay+Primary=2, Primary Only=1) 1
4 Design Storm 100 'Q,V7' Link to:
5 Weighted Runoff Coefficient C 0.50
6 Area A (Acres) 0.40 acres
7 Approved Discharge Rate (if applicable) 0.00 cfs
8 V 690 ft3
Toggle between Forebay and Primary Basin, enter data and print for each
Forebay
9 Select Forebay Shape
10 Width of Forebay Bottom W 33.0 ft
11 Length of Forebay Bottom L 40.0 ft
12 Side Slopes (H:1) H:1 4.00
13 Enter Bottom Elevation 2664.87 ft
14 Enter Top Bank Elevation 2666.37 ft
15 Enter Water Surface Elevation (WSE) 2665.87 ft
16 Distance Between Forebay and Primary Basin (blank if na) 0.00 ft
17 Enter Elevation Berm 0.00 ft
18 Enter High Groundwater Elevation 0.00 ft
19 Min. Freeboard Requirement 0.50
20 Freeboard Provided 0.50
21 Infiltration Area for Forebay Infiltration? 6.00 in/hr Note: infiltration required if
Design Infiltration Rate, Enter 0 for no infiltration bottom slope<1% or 0 outflow
22 Infiltration Area for Forebay ASand 1,320 ft2
Enter 0 for no infiltration
23 Adjusted Storage Required
i total Q
Runoff
Vol
Perc Vol
Pre-Dev
Discharge
Total
Discharge
Max Vol
Reqd
Min Hr in/hr cfs ft3 ft3 ft3 ft3 ft3
60 1.00 0.96 0.19 690 660 0 660 30
24 Depth-Storage Relationship:
2664.87 2664.87 4.000 33.0 40.0 1,320 0.00 0
2665.87 4.000 41.0 48.0 1,968 0.00 1,644
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
1.00 ft depth for storage STORAGE OK
25 Does forebay have capacity? YES
26 Time to drain forebay 0.9 hours
90% volume in 48-hours minimum OK
Saved
Surface
Steps for Sizing Basins: Size for forebay and print then size for primary storage/treatment basin.
User input in yellow cells.
1 Project Name
3
2 Enter number of Basins (25 max) 3
3 Number of Cells (Forebay+Primary=2, Primary Only=1) 1
4 Design Storm 100 'Q,V8' Link to:
5 Weighted Runoff Coefficient C 0.50
6 Area A (Acres) 0.13 acres
7 Approved Discharge Rate (if applicable) 0.00 cfs
8 V 230 ft3
Toggle between Forebay and Primary Basin, enter data and print for each
Forebay
9 Select Forebay Shape
10 Width of Forebay Bottom W 33.0 ft
11 Length of Forebay Bottom L 20.0 ft
12 Side Slopes (H:1) H:1 4.00
13 Enter Bottom Elevation 2667.35 ft
14 Enter Top Bank Elevation 2668.85 ft
15 Enter Water Surface Elevation (WSE) 2668.35 ft
16 Distance Between Forebay and Primary Basin (blank if na) 0.00 ft
17 Enter Elevation Berm 0.00 ft
18 Enter High Groundwater Elevation 0.00 ft
19 Min. Freeboard Requirement 0.50
20 Freeboard Provided 0.50
21 Infiltration Area for Forebay Infiltration? 6.00 in/hr Note: infiltration required if
Design Infiltration Rate, Enter 0 for no infiltration bottom slope<1% or 0 outflow
22 Infiltration Area for Forebay ASand 660 ft2
Enter 0 for no infiltration
23 Adjusted Storage Required
i total Q
Runoff
Vol
Perc Vol
Pre-Dev
Discharge
Total
Discharge
Max Vol
Reqd
Min Hr in/hr cfs ft3 ft3 ft3 ft3 ft3
60 1.00 0.96 0.06 230 330 0 330 0
24 Depth-Storage Relationship:
2667.35 2667.35 4.000 33.0 20.0 660 0.00 0
2668.35 4.000 41.0 28.0 1,148 0.00 904
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
0.00 0.00 0
1.00 ft depth for storage STORAGE OK
25 Does forebay have capacity? YES
26 Time to drain forebay 0.6 hours
90% volume in 48-hours minimum OK
Saved
Surface
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name
2 Enter number of Sand/Grease Traps (25 max) 5
Vault Size
Number of
S/G Traps
Peak Flow
Q-cfs
Baffle
Spacing
(inch)
Throat
width
(inch)
Area (ft2)
Velocity
0.5 fps
max.
Is the
Velocity
ok?
1000 G 1 2.72 18 48 6.00 0.45 YES
Reference for Throat widths (inch)
Boise
Vault
Lar-ken
ADS
WQU,
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
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.
Southridge South Phase 1
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name
2
2 Enter number of Sand/Grease Traps (25 max) 5
Vault Size
Number of
S/G Traps
Peak Flow
Q-cfs
Baffle
Spacing
(inch)
Throat
width
(inch)
Area (ft2)
Velocity
0.5 fps
max.
Is the
Velocity
ok?
1500 G 1 4 20 60 8.33 0.48 YES
Reference for Throat widths (inch)
Boise
Vault
Lar-ken
ADS
WQU,
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
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.
Southridge South Phase 1, Tank 2
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name
3
2 Enter number of Sand/Grease Traps (25 max) 5
Vault Size
Number of
S/G Traps
Peak Flow
Q-cfs
Baffle
Spacing
(inch)
Throat
width
(inch)
Area (ft2)
Velocity
0.5 fps
max.
Is the
Velocity
ok?
1000 G 1 1.2 18 48 6.00 0.20 YES
Reference for Throat widths (inch)
Boise
Vault
Lar-ken
ADS
WQU,
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
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.
Southridge South Phase 1, Tank 3
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name
4
2 Enter number of Sand/Grease Traps (25 max) 5
Vault Size
Number of
S/G Traps
Peak Flow
Q-cfs
Baffle
Spacing
(inch)
Throat
width
(inch)
Area (ft2)
Velocity
0.5 fps
max.
Is the
Velocity
ok?
1000 G 1 1.25 18 48 6.00 0.21 YES
Reference for Throat widths (inch)
Boise
Vault
Lar-ken
ADS
WQU,
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
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.
Southridge South Phase 1, Tank 4
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Steps for Sand/Grease Trap Velocity Calculation
User input in yellow cells.
1 Project Name
5
2 Enter number of Sand/Grease Traps (25 max) 5
Vault Size
Number of
S/G Traps
Peak Flow
Q-cfs
Baffle
Spacing
(inch)
Throat
width
(inch)
Area (ft2)
Velocity
0.5 fps
max.
Is the
Velocity
ok?
1000 G 1 3.14 20 48 6.67 0.47 YES
Reference for Throat widths (inch)
Boise
Vault
Lar-ken
ADS
WQU,
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
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.
Southridge South Phase 1, Tank 5
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Steps for Seepage Beds
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
2 Enter number of Seepage Beds (25 max) 5
3 Design Storm 100 'Q,V2'
4 Weighted Runoff Coefficient C 0.50 Link to:
5 Area A (Acres) 2.11 acres
6 Approved discharge rate (if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? No V 4,555 ft3
25% Sediment
8 Set Total Design Width of All Drain Rock W 10.0 ft
9 Set Total Design Depth of All Drain Rock D 11.5 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock Voids 0.35
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max) Perc 6.00 in/hr
12 Size of WQ Perf Pipe (Perf 180⁰) Dia pipe 18 in 1.8
13 Size of Overflow Perf Pipe (Perfs 360⁰), REQD if Q100>3.3 cfs in 0.0
14 Calculate Total Storage per Foot Spf 45.5 ft3/ft
15 Calculate Design Length L 100 ft 100.0743792
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 100 ft
17 Variable Infiltration Window W SWW 10.0 ft
18 Time to Drain 8.2 hours
90% volume in 48-hours minimum OK
19 Length of WQ & Overflow Perf Pipes 100 ft
20 Perf Pipe Checks. Qperf >= Qpeak; OK
where Qperf=CdxAx√(2xgxH) d 0.0313 ft
Optional Storage Chambers
Note: This assumes chambers are organized in a rectangular layout.
1 Type of Chambers
1-StormTech,
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 #DIV/0! hours
90% volume in 48-hours minimum #DIV/0!
ACHD Calculation Sheet for Sizing Seepage Bed With Optional Chambers
Note this spreadsheet pulls information from the "Peak Q,V" tab
Southridge South Phase 1, Facility 2
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.
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:22 AM
12/06/21
FP-2021-0059
Steps for Seepage Beds
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
2
2 Enter number of Seepage Beds (25 max) 5
3 Design Storm 100 'Q,V3'
4 Weighted Runoff Coefficient C 0.50 Link to:
5 Area A (Acres) 3.10 acres
6 Approved discharge rate (if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? No V 6,697 ft3
25% Sediment
8 Set Total Design Width of All Drain Rock W 10.0 ft
9 Set Total Design Depth of All Drain Rock D 11.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock Voids 0.35
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max) Perc 6.00 in/hr
12 Size of WQ Perf Pipe (Perf 180⁰) Dia pipe 18 in 1.8
13 Size of Overflow Perf Pipe (Perfs 360⁰), REQD if Q100>3.3 cfs in 0.0
14 Calculate Total Storage per Foot Spf 43.8 ft3/ft
15 Calculate Design Length L 153 ft 153.0191149
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 153 ft
17 Variable Infiltration Window W SWW 10.0 ft
18 Time to Drain 7.9 hours
90% volume in 48-hours minimum OK
19 Length of WQ & Overflow Perf Pipes 153 ft
20 Perf Pipe Checks. Qperf >= Qpeak; OK
where Qperf=CdxAx√(2xgxH) d 0.0313 ft
Optional Storage Chambers
Note: This assumes chambers are organized in a rectangular layout.
1 Type of Chambers
1-StormTech,
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 #DIV/0! hours
90% volume in 48-hours minimum #DIV/0!
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
Southridge South Phase 1, Facility 3, Bed 2
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:22 AM
12/06/21
FP-2021-0059
Steps for Seepage Beds
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
3
2 Enter number of Seepage Beds (25 max) 5
3 Design Storm 100 'Q,V4'
4 Weighted Runoff Coefficient C 0.50 Link to:
5 Area A (Acres) 0.93 acres
6 Approved discharge rate (if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? No V 2,012 ft3
25% Sediment
8 Set Total Design Width of All Drain Rock W 8.0 ft
9 Set Total Design Depth of All Drain Rock D 9.0 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock Voids 0.35
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max) Perc 6.00 in/hr
12 Size of WQ Perf Pipe (Perf 180⁰) Dia pipe 18 in 1.8
13 Size of Overflow Perf Pipe (Perfs 360⁰), REQD if Q100>3.3 cfs in 0.0
14 Calculate Total Storage per Foot Spf 29.5 ft3/ft
15 Calculate Design Length L 68 ft 68.28367768
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 68 ft
17 Variable Infiltration Window W SWW 8.0 ft
18 Time to Drain 6.6 hours
90% volume in 48-hours minimum OK
19 Length of WQ & Overflow Perf Pipes 68 ft
20 Perf Pipe Checks. Qperf >= Qpeak; OK
where Qperf=CdxAx√(2xgxH) d 0.0313 ft
Optional Storage Chambers
Note: This assumes chambers are organized in a rectangular layout.
1 Type of Chambers
1-StormTech,
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 #DIV/0! hours
90% volume in 48-hours minimum #DIV/0!
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
Southridge South Phase 1, Facility 4, Bed 3
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:22 AM
12/06/21
FP-2021-0059
Steps for Seepage Beds
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
4
2 Enter number of Seepage Beds (25 max) 5
3 Design Storm 100 'Q,V5'
4 Weighted Runoff Coefficient C 0.50 Link to:
5 Area A (Acres) 1.81 acres
6 Approved discharge rate (if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? No V 3,906 ft3
25% 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 0.35
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max) Perc 6.00 in/hr
12 Size of WQ Perf Pipe (Perf 180⁰) Dia pipe 18 in 1.8
13 Size of Overflow Perf Pipe (Perfs 360⁰), REQD if Q100>3.3 cfs in 0.0
14 Calculate Total Storage per Foot Spf 24.5 ft3/ft
15 Calculate Design Length L 159 ft 159.3184184
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 159 ft
17 Variable Infiltration Window W SWW 10.0 ft
18 Time to Drain 4.4 hours
90% volume in 48-hours minimum OK
19 Length of WQ & Overflow Perf Pipes 159 ft
20 Perf Pipe Checks. Qperf >= Qpeak; OK
where Qperf=CdxAx√(2xgxH) d 0.0313 ft
Optional Storage Chambers
Note: This assumes chambers are organized in a rectangular layout.
1 Type of Chambers
1-StormTech,
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 #DIV/0! hours
90% volume in 48-hours minimum #DIV/0!
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
Southridge South Phase 1, Facility 5, Bed 4
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:22 AM
12/06/21
FP-2021-0059
Steps for Seepage Beds
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
5
2 Enter number of Seepage Beds (25 max) 5
3 Design Storm 100 'Q,V6'
4 Weighted Runoff Coefficient C 0.50 Link to:
5 Area A (Acres) 2.43 acres
6 Approved discharge rate (if applicable) 0.00 cfs
7 Is Seepage Bed in Common Lot? No V 5,251 ft3
25% Sediment
8 Set Total Design Width of All Drain Rock W 10.0 ft
9 Set Total Design Depth of All Drain Rock D 11.5 ft
Rock Only, Do Not Include Filter Sand Depth or Cover
10 Void Ratio of Drain Rock Voids 0.35
0.4 for 1.5"-2" drain rock and 3/4" Chips
11 Design Infiltration Rate (8 in/hr max) Perc 6.00 in/hr
12 Size of WQ Perf Pipe (Perf 180⁰) Dia pipe 18 in 1.8
13 Size of Overflow Perf Pipe (Perfs 360⁰), REQD if Q100>3.3 cfs in 0.0
14 Calculate Total Storage per Foot Spf 45.5 ft3/ft
15 Calculate Design Length L 115 ft 115.3671066
Override Value Required for Chambers
16 Variable Infiltration Window L SWL 115 ft
17 Variable Infiltration Window W SWW 10.0 ft
18 Time to Drain 8.2 hours
90% volume in 48-hours minimum OK
19 Length of WQ & Overflow Perf Pipes 115 ft
20 Perf Pipe Checks. Qperf >= Qpeak; OK
where Qperf=CdxAx√(2xgxH) d 0.0313 ft
Optional Storage Chambers
Note: This assumes chambers are organized in a rectangular layout.
1 Type of Chambers
1-StormTech,
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 #DIV/0! hours
90% volume in 48-hours minimum #DIV/0!
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
Southridge South Phase 1, Facility 6, Bed 5
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:22 AM
12/06/21
FP-2021-0059
Southridge South Subdivision – Phase 1
Meridian, ID
Storm Water Management Report
Appendix C
Geotechnical Report
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
12/06/21
FP-2021-0059
Area A at
Stage (ft
2
)
Surface
Area A at
Stage (ft
2
)
OVERIDE
Volume
Below
Stage (ft3)
Saved
Stage (ft) New Stage (ft)
Side Slope
(H:V)
Basin
Width at
Stage (ft)
Basin
Length at
Stage (ft)
Surface
Area A at
Stage (ft 2 )
Storm Duration
ACHD Calculation Sheet for Sizing Basins
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.
Southridge South Phase 1, Facility 8, Pond 3
1-Basin Forebay
3-Rectangle
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Area A at
Stage (ft
2
)
Surface
Area A at
Stage (ft
2
)
OVERIDE
Volume
Below
Stage (ft3)
Saved
Stage (ft) New Stage (ft)
Side Slope
(H:V)
Basin
Width at
Stage (ft)
Basin
Length at
Stage (ft)
Surface
Area A at
Stage (ft 2 )
Storm Duration
ACHD Calculation Sheet for Sizing Basins
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.
Southridge South Phase 1, Facility 7, Pond 2
1-Basin Forebay
3-Rectangle
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Volume
Below
Stage (ft3)
Side Slope
(H:V)
Basin
Width at
Stage (ft)
Basin
Length at
Stage (ft)
Surface
Area A at
Stage (ft2)
Saved
Surface
Area A at
Stage (ft
2
)
Surface
Area A at
Stage (ft
2
)
OVERIDE
Southridge South Phase 1
3-Rectangle
1-Basin Forebay
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.
ACHD Calculation Sheet for Sizing Basins
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.0, May 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
Calculate Overland Flow Time of Concentration in Minutes (Tc) or use default 10
min
G:\2021\121027\CAD\Calcs and Reports\121027 ACHD_SD_CALCS_112018.xlsm
Version 10.5, November 2018
10/11/2021, 10:19 AM
12/06/21
FP-2021-0059
G
G G G G G
S
AN
SAN
SAN
SAN
SAN
SAN
SAN
MTR
WTR
SD
8''PI
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
R/W
FACILITY 7a
2889 SF
FACILITY 7b
14513 SF
Q100=1.41 cfs
Qq25=1.01 cfs
Q100=1.61 CFS
Q25=0.94 CFS
Q100=2.28 CFS
Q25=1.63 CFS
Q100=1.72 CFS
Q25=1.23 CFS
Q100=0.59 CFS
Q25=0.42 CFS
Q100=0.61 CFS
Q25=0.44 CFS
Q100=1.08 CFS
Q25=0.78 CFS
Q100=1.25 CFS
Q25=0.89 CFS
Q100=1.45 CFS
Q25=1.04 CFS
Q100=1.69 CFS
Q25=1.21 CFS
TEMPORARY DRINAGE
SWALE
V100=605 CF
TEMPORARY DRAINAGE SWALE
V100=690 CF
FACILITY 8b
2912 SF
FACILITY 8a
2897 SF
TEMPORARY DRAINAGE SWALE
V100=230 CF
FACILITY 1
AREA 8477 SF
FACILITY 6b
AREA
48874
SF
FACILITY 6a
AREA
57020
SF
FACILITY 2b
AREA
44282
SF
FACILITY 2a
AREA
47575
SF
FACILITY 3a
AREA
76980
SF
FACILITY 3b
AREA
58074
SF
FACILITY 5a
AREA
42144
SF
FACILITY 4a
AREA
20644
SF
FACILITY 4b
AREA
19931
SF
FACILITY 5b
AREA
36621
SF
Horizontal Scale:
0 80' 160'
1" = 80'
Drainage Map
File Location: \oak\cad\2021\121027\cad\calcs and reports\121027 drainage map.dwg
Last Plotted By: jason densmer
Date Plotted: Wednesday, October 27 2021 at 09:32 AM
####
####
Southridge South Subdivision Phase 1
Drainage Map
MERIDIAN, IDAHO
121027
App A
Drainage Map
Revisions
1.
Date of Issuance:
Project No.:
Project Milestone:
----
1
CONSTRUCTION
NOT FOR
12/06/21
FP-2021-0059