CC - Storm Drainage Calcs MERIDIAN, IDAHO
Sky Mesa Highlands
Subdivision
Stormwater Drainage Report
October 2020
Prepared by:
V'B i
J-U-B ENGINEERS, Inc.
2760 W Excursion Lane, Suite 400
Meridian, Idaho 83642
208-376-7330
web.JUB.com
SITE LOCATION
The project site is located on the northwest corner of the intersection of S. Eagle Road
and E. Lake Hazel Road, in the SE 1/4 of Section 32, Township 3 North, Range 1 East,
Boise meridian.
EXISTING SITE CHARACTERISTICS
The 32.9 acre project site is broken into two parts. The part north of the farm road and
gravity irrigation system is partially developed. This part is graded per a previously
approved grading plan. The part south of the farm road and gravity irrigation system is
relatively flat irrigated farmland and slopes down-gradient to the east and north at slopes
up to 5%.
PROPOSED SITE IMPROVEMENTS
The proposed improvements include the construction of 82 residential lots, 10 common
lots, 2 common driveway lots, and associated streets, sidewalks, and infrastructure. Lot
28, Block 1, while included in the plat, is not included in these storm drain calculations.
This lot is to remain separate from the subdivision and encompasses an existing
residence.
SOIL CONDITIONS
The following geotechnical reports were referenced during design of this stormwater
system.
Geotechnical Evaluation, Sky Mesa Highlands Subdivision, Meridian, Idaho, dated 28 Jan
2000, prepared by ALLWEST Testing & Engineering, Inc.
Groundwater Monitoring, dated July 2020, prepared by ALLWEST Testing & Engineering,
Inc.
According to the reports, high groundwater can be anticipated at depths from
approximately 5.4-ft to over 13-ft below the existing ground surface. Based on the
information provided in the geotechnical reports, the roadway finish grade centerline
elevations were designed to be more than 3-ft above the anticipated groundwater
elevations.
Based upon the preliminary soils and subsurface investigation for this subdivision, the
existing soils will accept the runoff. Seepage beds are designed based on assumed
maximum infiltration rate of 8.0 inches per hour.
In the event that during construction the contractor encounters groundwater or rock, or
the field percolation test results are lower than the design infiltration rate, a revised design
may be prepared to meet the field conditions.
DRAINAGE DESIGN CONCEPT
The project consists of 10 catchments labeled A through K. Catchment letter I is omitted
for clarity.
4
Stormwater in catchments A through H shall flow above grade to designed low points
where it shall be collected via curb inlets. The stormwater shall then pass through a pipe
network and discharge into a sub-surface seep bed for infiltration through a sand filter
into the groundwater network.
Catchments J and K flow off-site toward a future phase stormwater system. Temporary
drainage shall be provided for existing portions of this phase where the permanent storm
drainage system is to be constructed as a portion of a future phase. Storm water shall
flow above grade to designated low points into open channels which flow into a temporary
pond.
Catchment H includes the entirety of catchments J and K. Once the remaining phase is
constructed, the ponds for catchments J and K will be removed and the stormwater in
these two catchments shall be a part of catchment H. The storm systems in catchment
H are designed to include catchments J and K.
CALCULATION METHODS
The site was divided into catchment areas based on the proposed grading design. These
catchment areas were analyzed using the rational method to estimate the peak runoff
rates in accordance with ACHD Policy Manual Sections 8000 and 8200 in effect as of
August 2017.
Peak storage volumes were based on the 100-year, 1-hour design storm event of 0.96
inches per hour. Peak flow rates and conveyance flow rates were calculated for each
basin based on the 100-year and 25-year design storms, respectively. The time of
concentration for each basin was used as the design storm duration to calculate both the
peak flow and conveyance flow rates. Time of concentration values were calculated as
a combination of sheet flow from the lots to the road section and gutter flow along the
road. Specific equations are shown in the attached drainage calculations. The
conveyance flow rate was used to size inlets and pipes and determine acceptable pipe
slopes within the system.
The catchment areas are shown on the Drainage Plan. Calculations are included with
this report for all catchment areas.
5
Catchment A Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
Al 2724.67 2698.59 1154 0.619 2.26 3.05 6.31 gutter
A2 2703.95 2698.59 188 0.619 2.85 3.43 0.91 0.007(nL)0.8
Tc-sheet - (p2)0.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, C2 Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
Al 0.24 55.0 1.2 0.01 19.1 25.4 0.50 2.52 0.50 2.52
A2 0.24 20.0 1.2 0.01 8.5 10.0 0.50 0.19 0.50 0.19
Total Area 2.71
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iloo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
Al 0.43 1.14 1.35 1.57 0.54 1.44 1.70 1.98
A2 0.69 1.85 2.20 2.58 0.07 0.18 0.21 0.25
0.61 1.62 1.91 2.23
V.2020-03-17
Catchment A Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? No
the bed inside the right-of-way? No
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 2.71 ac
Sediment factor(f)= 0 %
Required Storage Volume(V100) 4,683 ft 3 Vion = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 60 ft
Depth (D)= 4.5 ft
Void Ratio(e)= 40 % Vol (Ve u)= 105.2 ft3
Inlet pipe size(dl)= 18 in Qty(d1I)= 4 Vol (VP1)= 7.07 ft 3
Overflow pipe size(d2)= 12 in Qty(d2q)= 0 Vol (VP2)= 0.00 ft,
Infiltration/LF(Fu)= 40.00 ft 3
Storage Vol/LF(Su)= 108.71 ft3
Vol based lenth (Lv)= 43.08 ft
Drain based length (Lp)= 2.44 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 43.08 43.25 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 4683 4,702 cf water V>_V100 PASS
Time to Drain 90%(t90)= 2.4 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.50 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length Max allowed bed length= 386 ft
1 ft
2 ft
3 ft
4 ft
Total Length (ILs b)= ft Single bed design
EQUATIONS:
Fr rc • d2 • d1g 7c• d2 •d2g
F,, = W ' 12 VP1 = 48 VP2 — 48
VeU = e • ((W • D) —VP1 —VP2) Su = VeU +V21 + VP2 + Fu
Vioo V100 0.9 • V100 _ 0.9 V100
Lp = S LD V= 48 F• = Sp L t90 = F•u L Fxmin — 4 W • L
U a
V.2020-03-17
Catchment A Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB A2 to CB Al 0.18 0.010 12 1.15 3.00 13.00 19.99 8.13 6.60
CB A2 to S&G A 1.62 0.010 12 0.22 3.04 64.24 5.57 9.99 25.98
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(e — sin B) A r
A = rc • r2 — 2 Rh = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment A Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 2.23 cfs
Water Quality Flow Rate(QWQ) 1.62 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.33 fps
No.of S&G Traps= 1 WQ Throat Velocity(v,r,,Q)= 0.24 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(QMax)= 2.23 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7 FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment B Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
B 2724.67 2703.95 974 0.619 2.13 2.96 5.49 gutter
0.007(nL)0.8
Tc-sheet - W2)O.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
B 0.24 55.0 1.2 0.01 19.1 24.5 0.50 1.46 0.50 1.46
Total Area 1.46
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
B 0.44 1.15 1.37 1.60 0.32 0.84 1.00 1.17
0.32 0.84 1.00 1.17
V.2020-03-17
Catchment B Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? No
the bed inside the right-of-way? No
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 1.46 ac
Sediment factor(f)= 0 %
Required Storage Volume(V100) 2,523 ft 3 Vion = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 15 ft
Depth (D)= 4.5 ft
Void Ratio(e)= 40 % Vol (Ve U)= 26.3 ft3
Inlet pipe size(dl)= 18 in Qty(d1I)= 1 Vol (VP1)= 1.77 ft 3
Overflow pipe size(d2)= 12 in Qty(d2q)= 0 Vol (VP2)= 0.00 ft,
Infiltration/LF(Fu)= 10.00 ft 3
Storage Vol/LF(Su)= 27.18 ft 3
Vol based lenth (Lv)= 92.84 ft
Drain based length (LO)= 5.26 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 92.84 93.00 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 2523 2,527 cf water V>_V100 PASS
Time to Drain 90%(t90)= 2.4 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.50 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length Max allowed bed length= 386 ft
1 ft
2 ft
3 ft
4 ft
Total Length (ILs b)= ft Single bed design
EQUATIONS:
Fr rc • d2 • d1g 7c• d2 •d2g
F,, = W ' 12 VP1 = 48 VP2 — 48
VeU = e • ((W • D) —VP1 —VP2) Su = VeU +V21 + VP2 + Fu
Vioo V100 0.9 • V100 _ 0.9 V100
Lp = S LD V= 48 F = Sp L t90 = F•u L Fxmin — 4 W • L
U a
V.2020-03-17
Catchment B Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB B to S&G B 0.84 0.010 12 0.33 3.01 38.55 9.59 9.99 16.40
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(e — sin B) R A r
A = rc • r2 — 2 h = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment B Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 1.17 cfs
Water Quality Flow Rate(QWQ) 0.84 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.18 fps
No.of S&G Traps= 1 WQ Throat Velocity(vwQ)= 0.13 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(Qmaj= 1.17 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment C Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
C1 2703.95 2693.83 517 0.619 1.96 2.84 3.03 gutter
C2 2694.67 2693.83 143 0.619 0.59 1.56 1.53 0.007(nL)0.8
Tc-sheet - (p2)0.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
C1 0.24 64.0 1.2 0.01 21.5 24.5 0.50 0.91 0.50 0.91
C2 0.24 15.0 1.2 0.01 6.7 10.0 0.50 0.13 0.50 0.13
Total Area 1.04
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
C1 0.44 1.15 1.37 1.60 0.20 0.52 0.62 0.73
C2 0.69 1.85 2.20 2.58 0.04 0.12 0.14 0.17
0.24 0.64 0.76 0.90
V.2020-03-17
Catchment C Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? No
the bed inside the right-of-way? No
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 1.04 ac
Sediment factor(f)= 0 %
Required Storage Volume(V100) 1,798 ft 3 V = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 4 ft
Depth (D)= 4.5 ft
Void Ratio(e)= 40 % Vol (Ve U)= 6.5 ft 3
Inlet pipe size(d1)= 18 in Qty(d1I)= 1 Vol (VP1)= 1.77 ft 3
Overflow pipe size(d2)= 12 in Qty(d2,)= 0 Vol (VP2)= 0.00 ft,
Infiltration/LF(Fu)= 2.67 ft 3
Storage Vol/LF(S,)= 7.38 ft 3
Vol based lenth (Lv)= 243.74 ft
Drain based length (LO)= 14.03 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 243.74 244.00 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 1798 1,800 cf water V>_V100 PASS
Time to Drain 90%(t90)= 2.5 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.50 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length Max allowed bed length= 386 ft
1 ft
2 ft
3 ft
4 ft
Total Length (ILs b)= ft Single bed design
EQUATIONS:
Fr rc • d2 • d1g 7c• d2 •d2g
F,, = W ' 12 VP1 = 48 VP2 — 48
VeU = e • ((W • D) —VP1 —VP2) Su = VeU +V21 + VP2 + Fu
Vioo V100 0.9 • V100 _ 0.9 V100
Lp = S LD V= 48 F = Sp L t90 = F•u L Fxmin — 4 W • L
U a
V.2020-03-17
Catchment C Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB C2 to CB C1 0.12 0.010 12 1.63 3.00 9.85 19.99 7.19 5.45
CB C1 to S&G C 0.64 0.010 12 0.41 3.02 31.51 12.08 9.99 13.59
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(9 — sin B) A r �
A = rc • r2 — 2 Rh = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment C Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 0.90 cfs
Water Quality Flow Rate(QWQ) 0.64 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.14 fps
No.of S&G Traps= 1 WQ Throat Velocity(vwQ)= 0.10 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(Qmaj= 0.90 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment D Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
D1 2724.67 2697.83 1035 0.619 2.59 3.27 5.28 gutter
D2 2724.67 2697.83 1048 0.619 2.56 3.25 5.37 0.007(nL)0.8
Tc-sheet - (p2)0.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, C2 Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
D1 0.24 80.0 1.2 0.01 25.7 31.0 0.50 2.76 0.50 2.76
D2 0.24 72.0 1.2 0.01 23.6 29.0 0.50 1.73 0.50 1.73
Total Area 4.49
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 i50 iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
D1 0.40 1.04 1.25 1.46 0.55 1.44 1.73 2.01
D2 0.41 1.09 1.30 1.52 0.35 0.94 1.12 1.31
0.90 2.38 2.85 3.32
V.2020-03-17
Catchment D Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? No
the bed inside the right-of-way? No
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 4.49 ac
Sediment factor(f)= 0 %
Required Storage Volume(V100) 7,759 ft 3 Vion = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 33.5 ft
Depth (D)= 6 ft
Void Ratio(e)= 40 % Vol (Ve U)= 79.0 ft 3
Inlet pipe size(dl)= 18 in Qty(d1I)= 2 Vol (VP1)= 3.53 ft 3
Overflow pipe size(d2)= 12 in Qty(d2,)= 0 Vol (VP2)= 0.00 ft3
Infiltration/LF(Fu)= 22.33 ft 3
Storage Vol/LF(Su)= 80.75 ft 3
Vol based lenth (Lv)= 96.08 ft
Drain based length (Lp)= 7.24 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 96.08 96.50 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 7759 7,793 cf water V>_V100 PASS
Time to Drain 90%(t90)= 3.2 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.54 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length Max allowed bed length= 386 ft
1 ft
2 ft
3 ft
4 ft
Total Length (ILs b)= ft Single bed design
EQUATIONS:
Fr rc • d2 • d1g 7c• d2 •d2g
F,, = W ' 12 VP1 = 48 VP2 — 48
VeU = e • ((W • D) —VP1 —VP2) Su = VeU +V21 + VP2 + Fu
Vioo V100 0.9 • V100 _ 0.9 V100
Lp = S LD V= 48 F• = Sp L t90 = F•u L Fxmin — 4 W • L
U a
V.2020-03-17
Catchment D Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB D1 to SDMH D2 1.44 0.010 12 0.23 3.02 58.53 6.12 9.99 23.91
CB D2 to SDMH D2 0.94 0.010 12 0.31 3.03 41.70 8.72 9.99 17.73
SDMH D2 through S&G D 2.38 0.010 12 0.24 3.28 86.87 4.10 9.99 34.30
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(e — sin B) R A r
A = rc • r2 — 2 h = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment D Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 3.32 cfs
Water Quality Flow Rate(QWQ) 2.38 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.50 fps
No.of S&G Traps= 1 WQ Throat Velocity(vwQ)= 0.36 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(Qmaj= 3.32 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. OUT EL. IN-7FLOW
FL..
INLET BAFFLE WALL
Modified rom
ISPWC SO-624,2017
V.2020-03-17
Catchment E Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
E 2698.43 2695.11 456 0.619 0.73 1.74 4.37 gutter
0.007(nL)0.8
Tc-sheet - W2)O.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
E 0.24 75.0 1.2 0.01 24.4 28.8 0.50 1.70 0.50 1.70
Total Area 1.7
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
E 0.41 1.09 1.30 1.53 0.35 0.93 1.11 1.30
0.35 0.93 1.11 1.30
V.2020-03-17
Catchment E Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? Yes
the bed inside the right-of-way? Yes
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 1.70 ac
Sediment factor(f)= 25 %
Required Storage Volume(V100) 3,672 ft 3 Vion = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 17.5 ft
Depth (D)= 3.5 ft
Void Ratio(e)= 40 % Vol (Ve U)= 23.8 ft 3
Inlet pipe size(dl)= 18 in Qty(d1I)= 1 Vol (VP1)= 1.77 ft 3
Overflow pipe size(d2)= 12 in Qty(d2q)= 0 Vol (VP2)= 0.00 ft3
Infiltration/LF(Fu)= 11.67 ft 3
Storage Vol/LF(Su)= 36.35 ft 3
Vol based lenth (Lv)= 101.03 ft
Drain based length (LO)= 6.56 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 101.03 102.00 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 3672 3,707 cf water V>_V100 PASS
Time to Drain 90%(t90)= 2.8 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.50 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length Max allowed bed length= 386 ft
1 ft
2 ft
3 ft
4 ft
Total Length (ILs b)= ft Single bed design
EQUATIONS:
Fr rc • d2 • d1g 7c• d2 •d2g
F,, = W ' 12 VP1 = 48 VP2 — 48
VeU = e • ((W • D) —VP1 —VP2) Su = VeU +V21 + VP2 + Fu
Vioo V100 0.9 • V100 _ 0.9 V100
Lp = S LD V= 48 F = Sp L t90 = F•u L Fxmin — 4 W • L
U a
V.2020-03-17
Catchment E Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB E through S&G E 0.93 0.010 12 0.31 3.02 41.46 8.80 9.99 17.60
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(e — sin B) A r
A = rc • r2 — 2 Rh = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment E Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 1.30 cfs
Water Quality Flow Rate(QWQ) 0.93 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.20 fps
No.of S&G Traps= 1 WQ Throat Velocity(vwQ)= 0.14 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(Qmaj= 1.30 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7 FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment F Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
F 2694.57 2692.76 251 0.619 0.72 1.72 2.43 gutter
0.007(nL)0.8
Tc-sheet - W2)O.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, C2 Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
F 0.24 75.0 1.2 0.01 24.4 26.9 0.50 1.85 0.50 1.85
Total Area 1.85
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
F 0.42 1.12 1.33 1.55 0.39 1.04 1.23 1.43
0.39 1.04 1.23 1.43
V.2020-03-17
Catchment F Sky Mesa Highland
Project No.10-20-082
Vertical Sand Filter (BMP-21)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? Yes
the bed inside the right-of-way? No
PARAMETERS
Design Storm frequency 100 2 -year
Design Storm duration 1 1 -hour
Design Infiltration rate(Fr) 8.00 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50 0.50
Design Storm Inentsity(i) 0.96 0.26 in/hr
Catchment Area (A) 1.85 1.85 ac
Required Storage Volume(VRe ) 3,197 866 ft 3 V100 = C * i *A * 3600
DESIGN
Length (L)= 100 ft
Depth (D)= 3.5 ft
Void Ratio(e)= 40
Primary pipe size (dl)= 12 in Qty(d1q)= 1 Vol (VP1)= 78.53 ft3
Overflow pipe size(d2)= 18 in Qty(d2 )= 1 Vol (VP2)= 176.71 ft 3
RESULTS DESIGN CHECKS
Min Design
Chamber 1 Width (WI)= 6.13 6.50 ft
Chamber 2 Width (W2)= 15.39 15.50 ft
Total width= 23.02 23.50 ft
Ch 1 Req Vol (Vregl)= 866 cf water
Ch 1 Vol (V1)= 866 918 cf water V2>_VRegz PASS
Ch 2 Req Vol (Vreg2)= 2,171 cf water
Ch 2 Vol (V2)= 2,172 2,188 cf water V1>VReg100 PASS
Time to Drain 90%(t90)= 44.6 hr t90<_48 PASS
Min infil rate(FRm;,,)= 0.50 0.50 in/hr FRmin?0.5 PASS
V.2020-03-17
Catchment F Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB F to S&G F 1.04 0.010 12 0.28 3.00 45.41 8.01 9.99 19.02
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(e — sin B) R A r
A = rc • r2 — 2 h = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment F Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 1.43 cfs
Water Quality Flow Rate(QWQ) 1.04 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.21 fps
No.of S&G Traps= 1 WQ Throat Velocity(vwQ)= 0.16 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(Qmaj= 1.43 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment G Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
G1 2697.83 2694.00 732 0.619 0.52 1.46 8.36 gutter
G2 2694.69 2694.00 139 0.619 0.50 1.44 1.61 0.007(nL)0.8
Tc-sheet - (p2)0.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
G1 0.24 75.0 1.2 0.01 24.4 32.8 0.50 2.63 0.50 2.63
G2 0.24 75.0 1.2 0.01 24.4 26.0 0.50 0.53 0.50 0.53
Total Area 3.16
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 i50 iloo Q2 Q25 Qso Q100 Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
G1 0.37 0.98 1.17 1.37 0.49 1.29 1.54 1.80
G2 0.43 1.13 1.34 1.57 0.11 0.30 0.36 0.42
0.60 1.59 1.90 2.22
V.2020-03-17
Catchment G Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? Yes
the bed inside the right-of-way? Yes
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 3.16 ac
Sediment factor(f)= 25 %
Required Storage Volume(V,00) 6,826 ft3 V = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 12.5 ft
Depth (D)= 3.25 ft
Void Ratio(e)= 40 % Vol (Ve U)= 15.5 ft3
Inlet pipe size(dl)= 18 in Qty(d1I)= 1 Vol (VPJ)= 1.77 ft3
Overflow pipe size(d2)= 12 in Qty(d2q)= 0 Vol (VP2)= 0.00 ft3
Infiltration/LF(Fu)= 8.33 ft3
Storage Vol/LF(Su)= 24.76 ft3
Vol based lenth (Lv)= 275.72 ft
Drain based length (LO)= 17.07 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 275.72 277.00 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 6826 6,858 cf water V>_V100 PASS
Time to Drain 90%(t90)= 2.7 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.50 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length (ft) Volume(ft) Max allowed bed length= 386 ft
1 172 4,258
2 105 2,599
3
4
Total Length (ILs b)= 277 6,857 No volume match
EQUATIONS:
F,. rc • di dlq rc d2 d2q
Fu — W 12 VP1 — 48 VP2 — 48
Veu = e • ((W • D) —VP1 —VP2) Su V= VU + Zl + VP2 + Fu
_ 0.9 • V 0.9 Vioo
S Lv _Uoo Lo __ 48?00 V — SU L t90 F o FRmin — 4 W L
U U U L
V.2020-03-17
Catchment G Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB G2 to CB G1 0.30 0.010 12 0.75 3.00 18.48 19.99 9.49 8.40
CB G1 through S&G G 1.59 0.010 12 0.22 3.03 63.42 5.65 9.99 25.64
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = — h = 2r —y B = 2 arccos /I D
r2(9 — sin B) A r �
A = rc • r2 — 2 Rh = P P = 2rcr — rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment G Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25
Peak Flow Rate(QPeak) 2.22 in/hr
Water Quality Flow Rate(QWQ) 1.59 ac QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.33 fps
No.of S&G Traps= 1 WQ Throat Velocity(v,r,,Q)= 0.24 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(QMax)= 2.22 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7 FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment H Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc-gutter = 60 V
H1 2693.74 2688.72 576 0.619 0.87 1.89 5.08 gutter
H2 2691.36 2688.72 414 0.619 0.64 1.62 4.26 0.007(nL)0.8
Tc-sheet - (p2)0.SS0.4
Vgutter = 3.281kSp0'S
Tc = Tc-gutter + Tc-sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
H 1 0.24 65.0 1.2 0.01 21.8 26.9 0.50 1.50 0.50 1.50
H2 O.24 60.0 1.2 0.01 20.4 24.7 0.50 1.14 0.50 1.14
Total Area 2.64
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iloo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
H1 0.42 1.12 1.33 1.55 0.32 0.84 1.00 1.16
H2 O.43 1.15 1.36 1.59 0.25 0.66 0.78 0.91
0.57 1.50 1.78 2.07
V.2020-03-17
Catchment H Sky Mesa Highland
Project No.10-20-082
Seepage Bed (BMP-20)
DESIGN OPTIONS
ris
count for 1st hr of infiltration? No
the bed inside the right-of-way? No
PARAMETERS
Design Storm frequency 100 -year
Design Storm duration 1 -hour
Design Infiltration rate(Fr) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 2.64 ac
Sediment factor(f)= 0 %
Required Storage Volume(V100) 4,562 ft 3 Vion = C * i *A * 3600 * 1 +
DESIGN
Width (W)= 30 ft
Depth (D)= 4.5 ft
Void Ratio(e)= 40 % Vol (Ve U)= 52.6 ft 3
Inlet pipe size(dl)= 18 in Qty(d1I)= 2 Vol (VP1)= 3.53 ft 3
Overflow pipe size(d2)= 12 in Qty(d2q)= 0 Vol (VP2)= 0.00 ft3
Infiltration/LF(Fu)= 20.00 ft 3
Storage Vol/LF(Su)= 54.35 ft 3
Vol based lenth (Lv)= 83.93 ft
Drain based length (Lp)= 4.75 ft
RESULTS DESIGN CHECKS
Min Design
Bed length (L)= 83.93 84.00 ft 368>_L>_Lmin PASS
Bed Capacity(V)= 4562 4,566 cf water V>_V100 PASS
Time to Drain 90%(t90)= 2.4 hr t90<_48 PASS
Min infil rate (FRmin) = 0.50 0.50 in/hr
OPTIONAL MULTIPLE SUB-BEDS
Sub-Bed# Length Max allowed bed length= 386 ft
1 ft
2 ft
3 ft
4 ft
Total Length (ILs b)= ft Single bed design
EQUATIONS:
Fr rc • d2 • d1g 7c• d2 •d2g
F,, = W ' 12 VP1 = 48 VP2 — 48
VeU = e • ((W • D) —VP1 —VP2) Su = VeU +V21 + VP2 + Fu
Vioo V100 0.9 • V100 _ 0.9 V100
Lp = S LD V= 48 F• = Sp L t90 = F•u L Fxmin — 4 W • L
U a
V.2020-03-17
Catchment H Sky Mesa Highland
Project No.10-20-082
Pipe Sizing Allowable Limits
Velocity(ft/sec) Flow depth (%)
Min 3.0 0.0
Max 10.0 90.0
Minimum Pipe Slope Maximum Pipe Slope
Pipe Id Design Mannings Pipe Min. V Flow Max. V Flow
Flow Size Slope' Depth Slope Depth
(cfs) (n) (in) (%) (fps) (%) (%) (fps) (%)
CB H1 to SDMH H5 0.84 0.010 12 0.33 3.01 38.55 9.59 9.99 a16 16.40
CB H2 to SDMH H5 0.66 0.010 12 0.40 3.02 32.22 11.76 9.99 1113.89
CB H3 to SDMH H7 0.42 0.010 12 0.57 3.01 23.37 17.33 9.99 1110.19
CB H4 to SDMH H7 0.08 0.010 12 2.31 3.00 7.49 19.99 6.35 1 4.51
SDMH H5 to SDMH H4 1.50 0.010 12 0.23 3.04 60.10 5.92 9.99 1124.61
SDMH H7 to SDMH H4 0.50 0.010 12 0.49 3.00 26.51 14.92 9.99 1111.48
SDMH H4 to Bed H 2.00 0.010 12 0.22 3.15 75.45 4.70 9.99 1130.22
Pipe velocity solved using the Mannings equation at the respective flow depth.
Flow depth solved using itterative solutions of the Manning's equation
1.49 2 1
Q = .A . R3 . $2
n
D Cr hl Y
r = - h = 2r -y B = 2 arccos /I _
r2(e - sin B) R A r
A = rc • r2 - 2 h = P P = 2rcr - rO
h
Note:
'Slightly decreased slopes may be considered where the depth of flow will be 0.3 of the diameter or greater for design average flow. (10-State Standards, Paragraph
Z Maximum slopes greater than 20%require additional restraint. (10-State Standards, Paragraph 33.46)
V.2020-03-17
Catchment H Sky Mesa Highland
Project No.10-20-082
Sand and Grease Trap
Peak Flow Design Storm 100 -year
Water Quality Design Storm 25 -year
Peak Flow Rate(QPeak) 2.07 cfs
Water Quality Flow Rate(QWQ) 1.50 cfs QwQ = C * iwQ *A
Design Calculations
Vault Size= 1000 gallon Peak Throat Velocity(VPeak)= 0.31 fps
No.of S&G Traps= 1 WQ Throat Velocity(vwQ)= 0.23 fps
Baffle Spacing= 20 inch
Throat Width = 48 inch Allowed Max Flow rate(QMax,A)= 3.33 cfs
Total Throat Area= 6.67 ft 2 Max Flow rate(Qmaj= 2.07 cfs
Bypass Flow Rate= 0 cfs
Checks: VWQ<0.5 PASS
Bypass Required FALSE
LI LI
OUTLET BAFFLE WALL
EL. IN-7FLOW
EL. OUT
FLOW '
t 20"
INLET BAFFLE WALL
Modified rom
ISPWC SD-624,2017 -__-__-_____-__-
Throat velocity is less than 0.5 fps. Manhole used in lieu of Sand and Grease Trap
V.2020-03-17
Catchment J Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc—gutter =
J 0.619 60 • Vgutter
0.007(nL)0.8
Tc—sheet — W2)O.SS0.4
Vgutter = 3.281kSO--'
Tc = Tc—gutter + Tc—sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
J 0.24 20.0 1.2 0.01 8.5 10.0 0.50 0.02 0.50 0.02
Total Area 0.02
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
J 0.69 1.85 2.20 2.58 0.01 0.02 0.02 0.03
0.01 0.02 0.02 0.03
V.2020-03-17
Catchment J Sky Mesa Highland
Project No.10-20-082
Pond
Design Storm frequency 100 -year
Design Storm duration 60 -minutes
Soil Infiltration rate(rf) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 0.02 ac
Req.Storage Volume(V100) 35 ft3 V = C * i *A * 3600
Infiltration area (AF)= 24.14 ftz Account for 1st hr of infiltration? No
Pond infiltration rate(PF)= 16.09 ft3/hr
Time for 90%infiltration (t90%)= 1.96 hr t90%<48 PASS
First hour infiltration (F1)= 0 ft 3
Adj. Req.Storage Volume(VAd)= 35 ft3
Mainbay volume(VP)= 66 ft 3
Forebay Size Forebay Required= FALSE
Required volume(VR) = ft
Forebay volume(VF)1= ft3 VF>VR N/R
Total Pond Volume(VT) 66 ft3
Check: VT>VAdi PASS
Equations
rf
PF = AF . rf VAd j = V100 — F1
12
0.9 - V100
t9o�io = PF
V.2020-03-17
Catchment K Sky Mesa Highland
Project No.10-20-082
Gutter Flow Rational Method (TR-55)
Sub- Elev. 1 Elev. 2 Lgutter Intercept Slope(Sp) Vgutter Tc-gutter L
gutter
catchment (ft) (ft) (ft) Coeff. (k) N (fps) (min) Tc—gutter =
K 0.619 60 • Vgutter
0.007(nL)0.8
Tc—sheet — W2)O.SS0.4
Vgutter = 3.281kSO--'
Tc = Tc—gutter + Tc—sheet
Q = CLA
Sheet Flow Calculation Total T, Catchment Parameters
Sub- n L P2 s Tc-sheet Tc C, Area, CZ Areal CT AreaT
catchment (unitless) (ft) (in) (ft/ft) (min) (min) (ac) (ac) (ac)
K 0.24 20.0 1.2 0.01 8.5 10.0 0.50 0.02 0.50 0.02
Total Area 0.02
Comp.C 0.5
Design Storm Intensities Design Storm Flow Rates Soil Parameters
Sub- i2 i25 iso iioo Q2 Q25 Qso QZoo Infil. Rate
8.00 in/hr
catchment (in/hr) (in/hr) (in/hr) (in/hr) (cfs) (cfs) (cfs) (cfs) (F)
K 0.69 1.85 2.20 2.58 0.01 0.02 0.02 0.03
0.01 0.02 0.02 0.03
V.2020-03-17
Catchment K Sky Mesa Highland
Project No.10-20-082
Pond
Design Storm frequency 100 -year
Design Storm duration 60 -minutes
Soil Infiltration rate(rf) 8.00 in/hr
Weighted Runoff Coefficient(C) 0.50
Design Storm Inentsity(i) 0.96 in/hr
Catchment Area (A) 0.02 ac
Req.Storage Volume(Vloo) 35 ft3 V = C * i *A * 3600
Infiltration area (AF)= 24.14 ftz Account for 1st hr of infiltration? No
Pond infiltration rate(PF)= 16.09 ft3/hr
Time for 90%infiltration (t90%)= 1.96 hr t90%<48 PASS
First hour infiltration (F1)= 0 ft 3
Adj. Req.Storage Volume(VAd)= 35 ft3
Mainbay volume(VP)= 66 ft 3
Forebay Size Forebay Required= FALSE
Required volume(VR) = ft
Forebay volume(VF)1= ft3 VF>VR N/R
Total Pond Volume(VT) 66 ft3
Check: VT>VAdi PASS
Equations
rf
PF = AF . rf VAd j = V100 — F1
12
0.9 - V100
t9o�io = PF
V.2020-03-17
ACHD Intensity-Duration-Frequency
Intensity(inches per hour)
Design Storm 2 5 10 25 50 100
Tc(hr) Tc(min)
0.17 10 0.69 1.15 1.48 1.85 2.20 2.58
0.25 15 0.59 0.97 1.22 1.56 1.86 2.18
0.33 20 0.49 0.81 1.01 1.30 1.54 1.81
0.42 25 0.43 0.71 0.89 1.14 1.35 1.58
0.50 30 0.41 0.67 0.85 1.08 1.29 1.51
0.58 35 0.34 0.56 0.70 0.90 1.07 1.25
0.67 40 0.31 0.51 0.64 0.82 0.98 1.15
0.75 45 0.29 0.48 0.60 0.77 0.91 1.07
0.83 50 0.27 0.45 0.56 0.72 0.85 1.00
0.92 55 0.26 0.43 0.54 0.69 0.82 0.96
1.00 60 0.26 0.43 0.54 0.69 0.82 0.96
2.00 120 0.16 0.25 0.31 0.39 0.46 0.54
3.00 180 0.13 0.19 0.23 0.29 0.34 0.40
6.00 360 0.09 0.12 0.14 0.18 0.21 0.25
12.00 720 0.06 0.08 0.10 0.12 0.14 0.16
24.00 1440 0.04 0.06 0.06 0.08 0.09 0.10
Intensity Duration Frequency
3.00 2
-)K-5
-x-10
2.50 -�25
t 50
2.00 100
i
t
1.50
c
' x
1.00 � \x
x\X,x\x--x�
\)K- _ x�
0.50 - � � )\
-.-.- -------------x------ �
=�„
0.00 1---
10 15 20 25 30 35 40 45 50 55 60 120 180 360 720 1440
Duration (minutes)
TabIG 3-2. Manning's Roughness Coefficient(n)for Overland Shoat Flcw.16'
Estimated Runoff Coefficients for Various Surfaces
Surface Description n Type of Surface Runoff Coefficients"C"
Smooth asphalt 0.011 Business
Smooth concrete 0.012 Downtown areas 0.70-0.95
Ordinary concrete lining U-013 Urban neighborhoods 0.50-0.70
Good wood 0.014 Residential
Brick with cement mortar 1313114 Single Family 0.35-0.50
Multi--family 0.60-0.75
Vitrified clay 0-015 Residential(rural) 0.25-0.40
Cast iron 0-015 Apartrnent❑wellingAreas 0.70
Corrugated metal pipe 0.024 Industrial and Commercial
Cement rubble surface 0.024 tight areas 0.80
Fallcm (no residue) 0-O5 Heavyareas 0.90
Cultivated soils Parks,Cemeteries 0.10-0.25
Residue cover s 20% p.pg Playgrounds 0.20-0.35
Residue cover> 20% 0.17 Railroad yard areas 0.20-0.40
Unimproved areas 0.10-0.30
Range(natural) 0-13 Streets
Grass Asphalt 0.95
Short grass prairie 0.15 Concrete 0.95
L)ense grasses U-24 Brick 0.95
Bermuda grass 0-41 Roofs 0.95
Woods' Gravel 0.75
Light underbrush 0.40 Fields:Sandy soil Soil Type
Dense underbrush 0-BO slope A B C ❑
*When selecting n. consider cover to a height of about 30 rnrn- This is only part of 0.04 0.07 0.11 0.15
the la nt cover that wil I obstruct sheet flow. Flat:t}2%
Average:2-696 0.09 0.1.2 0.15 0.20
Table 3-3. Intercept Coefficients far Velocity vs.Slope Relationshlp of Equation 3-4 Steep:>6% 0.13 0.18 0.23 0.28
Land CoverlFlow Regirne k Adapted from ASCE
Forest with heavy ground litter:hay meadow(overland flow) 0-076 Recommend Standards for Wastewater Facilities
Trash fallow or minimum tillage cultivation:contour or strip cropped;wood)and 0-152
overhand flow) Table 33.41 Recommended Minimum Slopes
Short grass pasture overland flow) 0.213 llinirnum Slope in Feet
Cultivated straig ht.row(overland flow) 0.274 Nominal Surer Size P,r 100 Feet mr( '1DD m)
IN early bare and unfilled(overland Flow):alluvial fans in western mountain regiions 0.305 8 uich(2DO mm) D-40
Grassed waterwa shatlOvv concentrated floc 0.457 10 mch(250mm) D-28
Unpaved(shallow ooncenlrated Flow) 0-491
Paved area(sh elilow commnVBted flOw);small upland gullies 0-619 12 inch(300 mm) D-22
Tab1a 3-4. Typical Rarlpa of Manning%Coaffiolant(n)for Chanrm"and Plp"- 14 mch(350 mm) D-17
Ganovat 15 inch(375 mm) D_15
Cla.ae Cawuiu 16 inch(400 mm) D-14
c«lcrama I 0-010-0-015 18 inch(450 mm) D-12
CMP 0.0111-4,03T
Plasslc PIP& smootR 0.000-0.015 21 inch(525 mm) D-10
Waste P1 P, corn. arse o-01$-0.025 24 inch(600 mm) D-D8
Pavamn.UbWtnr ae%r 0.012-0.016
Small open chanr+aas 27 inch(675 mm) 0-067
GOl%crato 0.01 y-0.015 30 inch(750 mm) 0-058
R.bbra or ri 0-o2a.0.035
v slat o 0.02a-a.1g0 33 nch(825 mm} 0-D52
sera sa:a 0-01e_o-925 36 inch(900 mm) 0-046
Rvck c.t 1 0.025-0.045
Natural cnanaais iminp alraems.top wletrl at Roos stage;30 m(100 R)) 39 inch(975 mm} 0-041
Fain war—U— 1 0.02E-0.050 42 inch(1050 mm) 0-037
ftraqu10,so*t:pn wRh pools 0.040-0-150 1ILLP.//1VOl4lC»l 11 1 111/V-ICV MIS 11U 1U PU1
-Lower v94uaa aid pip.*
artd chanrt616
H2 1.14 o so goo
■■■■■■■■ SCALE IN FEET
H1
H 1.50
LEGEND
J K
0.02 K 0.02 — — PROJECT BOUNDARY
A2
� ■ C2 CATCHMENT BOUNDARY
0.19 0.13 mi ME — — — — — — — SUB—CATCHMENT BOUNDARY
•� 6 91 0 3 —i FLOW DIRECTION
0.■ Al INFILTRATION BED LOCATION
■�■Emom ■■■■■ F
E
® POND LOCATION
F
E1 1'85 24 CATCHMENT AREA (AC)
1.70
G1
I
I
i
Al
2.52
B
1.46
D2 D1
1.73 2.76
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MERIDIAN, IDAHO
STORM DRAIN CATCHMENT MAP
s Fire:oaaiNa e J-U-B ENGINEERS,INC.