HomeMy WebLinkAboutHEARTSIDE HILL LOT ADJUSTMENTS - MA230145 - SUBMITTAL DOCUMENTS - ROUND 2 - DRAINAGE REPORT
Highland Development Services, Inc.
6355 Fairgrounds Avenue, Suite 100 | Windsor, CO 80550 | 970.674.7550
Memorandum
TO: Basil Hamdan, P.E.
FROM: Jason Claeys
DATE: 1/17/24
PROJECT: Heartside Hill – Minor Amendment
HDS JOB NO: 21-1045-00
SUBJECT: Drainage Amendment Summary
This memo is prepared to summarize the drainage adjustment associated with the proposed
Minor Amendment and Minor Subdivision Plat.
The Heartside Hill project was approved in October of 2023 including the “Final Drainage Report
for Heartside Hill”, prepared by Highland Development Services, dated August 28, 2023. The
Heart of the Rockies Christian Church requested to preserve the existing modular building located
near the northwest corner of Heartside Hill. In order to preserve the modular, lot lines need to
be adjusted through the Minor Subdivision Plat process with a supporting Minor Amendment for
the Heartside Hill site plan and utility adjustments.
The preservation of the modular eliminates the need for an interim & ultimate condition for the
outfall of Basin OS1 and Rain Garden OS1. The interim/ultimate conditions are described within
the approved Heartside Hill - Utility Plans as Phase 4 and the supporting phasing detail on Sheet
5. Sheet 5 is now labeled as “Not Applicable”. Due to the confined area, the Rain Garden OS1
outlet needed to be updated to manage the 100-yr peak runoff from Basin OS1, rather than
conveying the previous 10-yr storm. The emergency overflow was updated to manage the 100-
yr overtopping flows in the event runoff exceeds the estimated 100-yr runoff rate or the outlet
clogs.
Other than the adjustments for the outlet and overflow detail for Basin OS1, all remaining
assumptions and calculations remain unaffected. Please reference the attached calculations and
updated Drainage Plan.
DDONOTPOLLUTE
RAINSTOWATERWAYS
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RAINSTOWATERWAYS
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DDONOTPOLLUTE
RAINSTOWATERWAYS
DUCTILEIRONNYLOPLAST
DDONOTPOLLUTE
RAINSTOWATERWAYS
DUCTILEIRONNYLOPLAST
TRILBY ROAD
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BLOCK 1
LOT 1
LOT 2
LOT 3
LOT 4
LOT 1
LOT 2
LOT 3
LOT 4
LOT 5
LOT 6
LOT 7
BLOCK 2
BLOCK 3
LOT 1
TRACT A
BLDG 1
BLDG 2 BLDG 3
BLDG 4
BLDG 5 BLDG 6
DETENTION POND D
100 YR PEAK INFLOW = 44.16 CFS
100 YR RELEASE RATE = 13.2 CFS
100-YR VOLUME = 0.90 AC-FT
100-YR WSE = 4911.03 FT
WQCV (40-HR) = 0.08 AC-FT
WQCV WSE = 4908.85 FT
(STANDARD WQ - AREA NOT
TREATED BY LID)
RAIN GARDEN D1
WQCV (12-HR) = 2,914 CU-FT
RAIN GARDEN OS1
WQCV (12-HR) = 1,845 CU-FT
AREA RESERVED
FOR STORMWATER
FACILITIES
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PREPARED BY OR UNDER THE
DIRECT SUPERVISION OF:
FOR AND ON BEHALF OF HIGHLAND
DEVELOPMENT SERVICES
REVIEW SET
NOT FOR
CONSTRUCTION
OFSHEET
DRAWN BY
CHECKED BY
DATE
SCALE (H)
HDS PROJECT #
SCALE (V)
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9/27/23
1" = 40'
N/A
JTC
JTC
21-1045-00
C2.00
9 27
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CALL UTILITY NOTIFICATION
CENTER OF COLORADO
CALL 2-BUSINESS DAYS IN ADVANCE BEFORE YOU
DIG, GRADE OR EXCAVATE FOR THE MARKING OF
UNDERGROUND MEMBER UTILITIES.
before you dig.CallKnow what's below.
R
N
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S
0
SCALE: 1" = 40'
80402040
LEGEND
EXISTING MAJOR CONTOUR
EXISTING MINOR CONTOUR
PROPOSED MAJOR CONTOUR
PROPOSED MINOR CONTOUR
BASIN COEFFICIENT (100-YR)
BASIN DESIGNATION
BASIN AREA
DESIGN POINT
DRAINAGE FLOW ARROW
DRAINAGE BASIN BOUNDARY
DRAINAGE BASIN FLOW PATH
NOTES
1.CONTRACTOR TO PROVIDE AND MAINTAIN ALL NECESSARY
EROSION CONTROL MEASURES PRIOR TO AND THROUGHOUT
CONSTRUCTION. PLACE EROSION CONTROL PROTECTION AT
ALL EXISTING INLETS DOWNSTREAM FROM THE CONSTRUCTION
AREA. EROSION CONTROL PROTECTION SHALL REMAIN IN
PLACE UNTIL CONSTRUCTION IS COMPLETE AND ALL DISTURBED
GROUND IS ADEQUATELY VEGETATED WITH OWNER'S APPROVAL
FOR REMOVAL.
2.THE EXTENT OF EROSION CONTROL PROTECTION SHALL BE
OBSERVED AND ADJUSTED AS NEEDED DURING CONSTRUCTION
BASED ON SITE CONDITIONS AND THE PERFORMANCE OF THE
EROSION CONTROL CONTROL MEASURES SHOWN, TO SUPPLY
SUFFICIENT EROSION CONTROL AND MINIMIZE DOWNSTREAM
WATERWAY POLLUTION.
3.LIMIT DISTURBANCE TO AREAS WITHIN EROSION CONTROL
BOUNDARIES. ADJUST EROSION CONTROL BOUNDARIES AS
NECESSARY TO ADEQUATELY COMPLETE PROPOSED WORK. ALL
DISTURBED AREAS SHALL BE PREPARED (SEEDED & MULCHED,
SURFACE ROUGHENING, ETC.) TO MINIMIZE EROSION POTENTIAL
AND SOIL MIGRATION.
4.STORMWATER MANAGEMENT PLAN SHALL BE PREPARED AND
SUBMITTED BY CONTRACTOR PRIOR TO CONSTRUCTION
COMMENCEMENT.
5.SEE LANDSCAPE PLAN FOR REVEGETATION METHODS AND
DETAILS. DURING CONSTRUCTION, ANY SOIL DISTURBED AND
NOT UNDER ACTIVE CONSTRUCTION SHALL BE SEEDED AND
MULCHED PER LCUASS STANDARDS.
6.ANY DISTURBED LAND MUST RECEIVE SURFACE ROUGHENING,
INCLUDING BUT NOT LIMITED TO SLOPED AREAS.
7.AREAS THAT EXPERIENCE EROSION ISSUES FROM STEEP SLOPES
OR WATER EROSION RESULTING IN SEED NOT BEING ABLE TO
ESTABLISH DURING THE FIRST GROWING SEASON SHALL REQUIRE
RESEEDING AND EROSION CONTROL BLANKETS TO STABILIZE THE
SOIL.
Heartside Hill
TYPE D AREA INLET SIZING CALCULATION
Design Engineer:
Design Firm:
Project Number:
Date:
DESIGN CRITERIA
EQUATIONS:
Q i = Grate Capacity w/o Reduction Factor (cfs)
C = Orifice Discharge Coefficient = 0.67
A = Orifice area (ft2) - Open Area of Grate
G = Gravitational Constant (32.2 ft/s2)
H = Allowed Head on Grate, Ponding Depth (ft)
Grate Dimensions and Information:
2.92 ft
5.67 ft
0.65 sqft/sqft
50%
10.76 sqft
Allowed Head (ft)
Inlet
Capacity
(Qi, cfs)
Inlet Capacity
w/ Reduction
Factor (Qg, cfs)
0.25 28.93 14.47
0.50 40.91 20.46
1.00 57.86 28.93
1.50 70.87 35.43
2.00 81.83 40.91
INLET SIZING CALCULATIONS
Inlet ID:
Design
Flow Rate
(Q 100 , cfs):
Allowed Head
(H , ft):
Inlet Capacity
(Qg, cfs)
Design
Flow Depth
(H, ft)
OS1 15.84 1.00 28.93 0.30
J.Claeys
Highland Development Services
21-1045-00
November 20, 2023
Apply Reduction Factor for the Allowable Capacity.
Assumed Capacity per Head Allowed
Width (W ):
Length (L ):
Opening Ratio (R ):
Reduction Factor (F ):
Inlet Grate Open Area (A ):
Heartside Hill
Emergency Overflow Spillway Calculations - Basin OS1
Design Engineer:
Design Firm:
Project Number:
Date:
Broad-Crested Weir Equation-Trapezoidal Shape
where:Q = Discharge (cfs)
C = Weir Coeffecient
L = Weir Length (ft)
H = Average Weir Head (ft)
H:V =Side Slope
Calculations
Knowns: 4.00
0.50 ft
2.6
4930.00 ft
15.84 cfs
15.23 ft
16 ft
0.50 ft
1.00 ft
4931.00 ft
Desired Spillway Head
J.Claeys
Highland Development Services
21-1045-00
November 20, 2023
Side Slopes (H:V)
Total Spillway Depth
Top of Berm Elevation
Weir Coefficient
Spillway Elevation
100-yr Pond Inflow
Calculated Spillway
Use Spillway Length
Spillway Freeboard
21-1045-00 PondCalcs.xlsx - Spillway (2) Page 1 of 1 Highland Development Services
Channel Report
Hydraflow Express Extension for Autodesk® Civil 3D® by Autodesk, Inc. Wednesday, Jan 17 2024
Basin OS1 - Emergency Outfall Channel
Rectangular
Bottom Width (ft) = 7.00
Total Depth (ft) = 2.00
Invert Elev (ft) = 4929.33
Slope (%) = 2.00
N-Value = 0.030
Calculations
Compute by: Known Q
Known Q (cfs) = 15.84
Highlighted
Depth (ft) = 0.54
Q (cfs) = 15.84
Area (sqft) = 3.78
Velocity (ft/s) = 4.19
Wetted Perim (ft) = 8.08
Crit Depth, Yc (ft) = 0.55
Top Width (ft) = 7.00
EGL (ft) = 0.81
0 1 2 3 4 5 6 7 8 9
Elev (ft)Depth (ft)Section
4928.50 -0.83
4929.00 -0.33
4929.50 0.17
4930.00 0.67
4930.50 1.17
4931.00 1.67
4931.50 2.17
4932.00 2.67
Reach (ft)
Heartside Hill
Design Engineer:
Design Firm:
Project Number:
Date:
Broad-Crested Weir Equation-Trapezoidal Shape
where:Q = Discharge (cfs)
C = Weir Coeffecient
L = Weir Length (ft)
H = Average Weir Head (ft)
H:V =Side Slope
Calculations
Knowns: 4.00
0.45 ft
2.6
4929.33 ft
15.84 cfs
18.38 ft
19 ft
1.00 ft
1.45 ft
4930.78 ft
Total Spillway Depth
Top of Berm Elevation
Emergency Overflow Spillway Calculations - Basin OS1 (Wall)
Weir Coefficient
Spillway Elevation
100-yr Pond Inflow
Calculated Spillway
Use Spillway Length
Spillway Freeboard
J.Claeys
Highland Development Services
21-1045-00
January 17, 2024
Side Slopes (H:V)
Desired Spillway Head
21-1045-00 PondCalcs.xlsx - Spillway (OS1-Wall) Page 1 of 1 Highland Development Services
N
W E
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SCALE: 1" = 20'
Screen shot from Sheet 14 - Grading Plan
showing the detail of the NW Rain Garden
spillway from Basin OS1