HomeMy WebLinkAboutSite Certifications - 01/06/2023
CERTIFICATION OF LOT GRADING
Date: November 13, 2020
Permit Application No. P-28976
Address: 1109 W Harmony Road, Fort Collins, CO.
Lot/Block/Subdivision: Lot 1, Montessori Subdivision
Exception:
I.3.f. There are no obstructions in the spillway, such as trees, bushes, sidewalks, landscape features,
rocks, etc.
There are three plants located in the spillway. The spillway will function as designed, as these plants will
not obstruct flow over the spillway.
II.A.2. Longitudinal slopes and side-slopes (cross-sections) have been verified. Design criteria
requires longitudinal slopes of 2% min. (on vegetated swales) and side-slopes no steeper than 4:1. If
these criteria are not met, the certification engineer will write a justification and propose mitigation
for each instance or have the issues corrected. If variances to these criteria have previously been
approved and are shown on the construction plans, no justification is needed.
Swale A-A has a slope of 1.1%. The approved Utility Plans called out a slope of 1.5%. Swale A-A has
adequate capacity to convey the 100-year event.
V.A.4. The as-built invert elevations of all pipes entering and leaving the inlet are shown on the
plan and profile sheets within construction tolerance of 0.2 feet. If substantially different, provide
justification and capacity calculations to show the capacity is not affected or propose mitigation.
The outlet pipe in the north rain garden was 0.74’ higher than designed. This was worked out with an
alternative rain garden cross section approved by the City of Fort Collins on 10/5/2020.
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PROPOSED BASIN FLOWS
EROSION BMP LEGEND
DETENTION SUMMARY
& REMOVAL OF BMP'S
SEQUENCE FOR INSTALLATION
EXISTING BASIN FLOWS
NOTE
CITY OF FORT COLLINS, COLORADO
UTILITY PLAN APPROVAL
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CITY OF FORT COLLINS, COLORADO
UTILITY PLAN APPROVAL
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BENCHMARK STATEMENT
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LEGEND:
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November 13th, 2020
Matt Simpson, PE
City of Fort Collins Development Review Engineer
700 Wood Street
Fort Collins, CO 80521
RE: Pond Certification for Fort Collins Montessori School
CES Project No. 2259.03
Dear Mr. Simpson,
This letter accompanies the calculations for the as constructed ponds information as serves as a pond
certification for the Fort Collins Montessori School site. All information provided in this letter is based
on a field survey completed by Coffey Engineering and Surveying dated October 28th, 2020 and a site
visit on October 30th, 2020.
It was observed that all erosion control mats, sediment forebays, storm pipes, and outlet structures were
installed in conformance with the approved Utility Plans.
The constructed ponds have sufficient volume at the 100-year water surface elevation of 5088.6’. The
pond was required to have a 100-year WSEL volume of 27,626 cubic feet and designed to have a 100-
year WSEL volume of 28,872 cubic feet. The constructed pond has a 100-year WSEL volume is 27,508
cubic feet. The as-built ponds were constructed with 99.5% of the required volume. A summary of the
detention pond and rain gardens can be found below.
Detention Pond Summary
Detention Pond As-Built Volume (ft3) Design Volume (ft3) Required Volume (ft3)
1 12,563 12,666 -
2 1,580 1,346 -
3 5,387 5,744 -
4 7,978 9,242 -
Total 27,508 28,998 27,626
Rain Garden Summary
Rain
Garden As-Built Volume (ft3) Require Volume (ft3) As-Built Flat Area (ft2) Design Flat Area (ft2)
1 800 738 535 464
2 1,568 1,240 969 697
3 567 542 385 346
Page 2
If you have any questions or require additional information, please call at (970) 622-2095.
Sincerely,
COFFEY ENGINEERING & SURVEYING, LLC
Ramsey J. Pickard, PE
Project Manager
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5083.60 (input)0 0.000 0.000
5084.00 0.00 0.00 263 53 0.006 0.001
5084.50 0.00 0.00 856 332 0.020 0.008
5085.00 0.00 0.00 1,353 885 0.031 0.020
5085.50 0.00 0.00 1,837 1,682 0.042 0.039
5086.00 0.00 0.00 2,348 2,728 0.054 0.063
5086.50 0.00 0.00 2,883 4,036 0.066 0.093
5087.00 0.00 0.00 3,444 5,618 0.079 0.129
5087.50 0.00 0.00 4,029 7,486 0.092 0.172
5088.00 0.00 0.00 4,640 9,653 0.107 0.222
5088.50 0.00 0.00 5,275 12,132 0.121 0.279
5088.60 0.00 0.00 5,405 12,666 0.124 0.291 100-YR
5089.10 0.00 0.00 5,070 15,285 0.116 0.351
5089.60 0.00 0.00 6,770 18,245 0.155 0.419
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Detention Pond 1
Detention Pond 1_v2.35.xls, Basin 10/14/2019, 4:57 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5083.30 (input)0 0.000 0.000
5084.00 0.00 0.00 703 246 0.016 0.006
5084.50 0.00 0.00 1,152 710 0.026 0.016
5085.00 0.00 0.00 1,556 1,387 0.036 0.032
5085.50 0.00 0.00 1,967 2,268 0.045 0.052
5086.00 0.00 0.00 2,387 3,356 0.055 0.077
5086.50 0.00 0.00 2,818 4,657 0.065 0.107
5087.00 0.00 0.00 3,259 6,177 0.075 0.142
5087.50 0.00 0.00 3,710 7,919 0.085 0.182
5088.00 0.00 0.00 4,172 9,889 0.096 0.227
5088.50 0.00 0.00 4,644 12,093 0.107 0.278
5088.60 0.00 0.00 4,740 12,563 0.109 0.288 100-YR
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Detention Pond 1
As-Built Detention Pond 1_v2.35.xls, Basin 11/13/2020, 10:19 AM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5086.10 (input)0 0.000 0.000
5086.50 0.00 0.00 95 19 0.002 0.000
5087.00 0.00 0.00 190 90 0.004 0.002
5087.50 0.00 0.00 560 278 0.013 0.006
5088.00 0.00 0.00 924 649 0.021 0.015
5088.50 0.00 0.00 1,321 1,210 0.030 0.028
5088.60 0.00 0.00 1,404 1,346 0.032 0.031 100-YR
5089.10 0.00 0.00 1,837 2,157 0.042 0.050
5089.60 0.00 0.00 2,300 3,191 0.053 0.073
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Detention Pond 2
Detention Pond 2_v2.35.xls, Basin 10/14/2019, 4:01 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5085.50 (input)0 0.000 0.000
5086.50 0.00 0.00 121 61 0.003 0.001
5087.00 0.00 0.00 464 207 0.011 0.005
5087.50 0.00 0.00 728 505 0.017 0.012
5088.00 0.00 0.00 953 925 0.022 0.021
5088.50 0.00 0.00 1,183 1,459 0.027 0.033
5088.60 0.00 0.00 1,229 1,580 0.028 0.036 100-YR
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Detention Pond 2
As-Built Detention Pond 2_v2.35.xls, Basin 11/13/2020, 10:20 AM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5084.95 (input)0 0.000 0.000
5085.00 0.00 0.00 31 1 0.001 0.000
5085.50 0.00 0.00 374 102 0.009 0.002
5086.00 0.00 0.00 815 399 0.019 0.009
5086.50 0.00 0.00 1,249 915 0.029 0.021
5087.00 0.00 0.00 1,718 1,657 0.039 0.038
5087.50 0.00 0.00 2,220 2,642 0.051 0.061
5088.00 0.00 0.00 2,755 3,885 0.063 0.089
5088.60 0.00 0.00 3,442 5,744 0.079 0.132 100-YR
5089.60 0.00 0.00 4,676 9,803 0.107 0.225
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Detention Pond 3
Detention Pond 3_v2.35.xls, Basin 10/14/2019, 4:02 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5084.90 (input)42 0.001 0.000
5085.00 0.00 0.00 100 7 0.002 0.000
5085.50 0.00 0.00 507 159 0.012 0.004
5086.00 0.00 0.00 858 500 0.020 0.011
5086.50 0.00 0.00 1,222 1,020 0.028 0.023
5087.00 0.00 0.00 1,608 1,728 0.037 0.040
5087.50 0.00 0.00 2,018 2,634 0.046 0.060
5088.00 0.00 0.00 2,451 3,751 0.056 0.086
5088.60 0.00 0.00 3,002 5,387 0.069 0.124 100-YR
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Detention Pond 3
As-Built Detention Pond 3_v2.35.xls, Basin 11/13/2020, 10:22 AM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5086.30 (input)0 0.000 0.000
5087.00 0.00 0.00 1,397 489 0.032 0.011
5087.50 0.00 0.00 3,719 1,768 0.085 0.041
5088.00 0.00 0.00 7,272 4,516 0.167 0.104
5088.60 0.00 0.00 8,482 9,242 0.195 0.212 100-YR
5089.60 0.00 0.00 16,654 21,810 0.382 0.501
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Detention Pond 4
Detention Pond 4_v2.35.xls, Basin 12/12/2019, 3:16 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5086.00 (input)0 0.000 0.000
5087.00 0.00 0.00 1,167 584 0.027 0.013
5087.50 0.00 0.00 3,836 1,834 0.088 0.042
5088.00 0.00 0.00 5,605 4,195 0.129 0.096
5088.60 0.00 0.00 7,006 7,978 0.161 0.183 100-YR
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Detention Pond 4
As-Built Detention Pond 4_v2.35.xls, Basin 11/13/2020, 10:23 AM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5088.30 (input)470 0.011 0.000
5088.50 0.00 0.00 630 110 0.014 0.003
5088.75 0.00 0.00 837 293 0.019 0.007
5089.00 0.00 0.00 1,052 529 0.024 0.012
5089.30 0.00 0.00 1,320 885 0.030 0.020 Grate
5089.50 0.00 0.00 1,504 1,168 0.035 0.027
5089.75 0.00 0.00 1,742 1,573 0.040 0.036
5090.00 0.00 0.00 1,987 2,040 0.046 0.047
5090.30 0.00 0.00 2,291 2,681 0.053 0.062 Top of RG
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Rain Garden 1
Rain Garden 1_v2.35.xls, Basin 2/17/2020, 2:52 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5088.40 (input)535 0.012 0.000
5088.50 0.00 0.00 616 58 0.014 0.001
5088.75 0.00 0.00 848 241 0.019 0.006
5089.00 0.00 0.00 990 470 0.023 0.011
5089.30 0.00 0.00 1,205 800 0.028 0.018 Grate
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Rain Garden 1
As-Built Rain Garden 1_v2.35.xls, Basin 11/13/2020, 10:24 AM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5090.25 (input)1,038 0.024 0.000
5090.50 0.00 0.00 1,306 293 0.030 0.007
5090.75 0.00 0.00 1,623 659 0.037 0.015
5091.00 0.00 0.00 2,002 1,112 0.046 0.026
5091.25 0.00 0.00 2,101 1,625 0.048 0.037 Spillway
5091.50 0.00 0.00 2,196 2,162 0.050 0.050
5091.75 0.00 0.00 2,312 2,726 0.053 0.063 Top of RG
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Rain Garden 2
Rain Garden 2_v2.35.xls, Basin 2/17/2020, 2:53 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5090.25 (input)969 0.022 0.000
5090.50 0.00 0.00 1,243 277 0.029 0.006
5090.75 0.00 0.00 1,546 625 0.035 0.014
5091.00 0.00 0.00 1,878 1,053 0.043 0.024
5091.25 0.00 0.00 2,240 1,568 0.051 0.036 Spillway
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Rain Garden 2
As-Built Rain Garden 2_v2.35.xls, Basin 11/13/2020, 10:25 AM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5088.25 (input)350 0.008 0.000
5088.50 0.00 0.00 528 110 0.012 0.003
5088.75 0.00 0.00 706 264 0.016 0.006
5089.00 0.00 0.00 880 462 0.020 0.011
5089.25 0.00 0.00 1,053 704 0.024 0.016 Grate
5089.50 0.00 0.00 1,223 988 0.028 0.023
5089.75 0.00 0.00 1,391 1,315 0.032 0.030
5090.00 0.00 0.00 1,558 1,684 0.036 0.039
5090.25 0.00 0.00 1,661 2,086 0.038 0.048 Top of RG
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
Rain Garden 3
Rain Garden 3_v2.35.xls, Basin 3/5/2020, 2:05 PM
Project:
Basin ID:
Design Information (Input):
Width of Basin Bottom, W = ft Right Triangle OR…
Length of Basin Bottom, L = ft Isosceles Triangle OR…
Dam Side-slope (H:V), Zd =ft/ft Rectangle OR…
Circle / Ellipse OR…
Irregular (Use Overide values in cells G32:G52)
MINOR MAJOR
Storage Requirement from Sheet 'Modified FAA': 0.09 0.54 acre-ft.
Stage-Storage Relationship:Storage Requirement from Sheet 'Hydrograph': acre-ft.
Storage Requirement from Sheet 'Full-Spectrum': acre-ft.
Labels Water Side Basin Basin Surface Surface Volume Surface Volume Target Volumes
for WQCV, Minor, Surface Slope Width at Length at Area at Area at Below Area at Below for WQCV, Minor,
& Major Storage Elevation (H:V) Stage Stage Stage Stage Stage Stage Stage & Major Storage
Stages ft ft/ft ft ft ft2 ft2 User ft3 acres acre-ft Volumes
(input) (input)Below El.(output) (output) (output)Overide (output) (output) (output) (for goal seek)
5088.25 (input)385 0.009 0.000
5088.50 0.00 0.00 546 116 0.013 0.003
5088.75 0.00 0.00 657 267 0.015 0.006
5089.00 0.00 0.00 772 445 0.018 0.010
5089.15 0.00 0.00 844 567 0.019 0.013 Grate
STAGE-STORAGE SIZING FOR DETENTION BASINS
Fort Collins Montessori School
Check Basin Shape
As-Built Rain Garden 3
As-Built Rain Garden 3_v2.35.xls, Basin 11/13/2020, 10:27 AM
Stormwater Facility Name:
Facility Location & Jurisdiction:
User Input: Watershed Characteristics User Defined User Defined User Defined User Defined
Watershed Slope =0.020 ft/ft Stage [ft] Area [ft^2] Stage [ft] Discharge [cfs]
Watershed Length =500 ft 0.00 0 0.00 0.00
Watershed Area = 4.29 acres 0.40 263 0.40 0.02
Watershed Imperviousness = 50.0%percent 0.90 856 0.90 0.02
Percentage Hydrologic Soil Group A = 0.0%percent 1.40 1,384 1.40 0.06
Percentage Hydrologic Soil Group B = 100.0%percent 1.90 2,211 1.90 0.07
Percentage Hydrologic Soil Groups C/D = 0.0%percent 2.40 3,163 2.40 0.07
2.90 4,227 2.90 1.05
User Input 17 3.40 6,749 3.40 1.14
3.90 10,528 3.90 1.22
4.40 15,591 4.40 1.30
5.00 18,733 5.00 1.39
WQCV Treatment Method = 40.00 hours 5.50 21,373 5.50 1.46
6.00 30,400 6.00 1.46
After completing and printing this worksheet to a pdf, go to:
https://maperture.digitaldataservices.com/gvh/?viewer=cswdif
create a new stormwater facility, and
attach the pdf of this worksheet to that record.
Routed Hydrograph Results
Design Storm Return Period =WQCV 2 Year 5 Year 10 Year 50 Year 100 Year
One-Hour Rainfall Depth =0.75 0.87 1.14 1.44 2.44 3.00 in
Calculated Runoff Volume =0.074 0.135 0.192 0.281 0.618 0.824 acre-ft
OPTIONAL Override Runoff Volume =acre-ft
Inflow Hydrograph Volume =0.073 0.135 0.191 0.281 0.617 0.823 acre-ft
Time to Drain 97% of Inflow Volume =17.2 18.0 17.3 16.5 16.3 16.8 hours
Time to Drain 99% of Inflow Volume =18.0 19.7 19.6 19.8 20.8 21.4 hours
Maximum Ponding Depth =2.29 2.73 3.01 3.49 4.55 5.01 ft
Maximum Ponded Area =0.07 0.09 0.11 0.17 0.38 0.43 acres
Maximum Volume Stored =0.064 0.098 0.125 0.191 0.479 0.667 acre-ft
Stormwater Detention and Infiltration Design Data Sheet
Fort Collins Montessori School
1109 West Harmony Road, Fort Collins Colorado, 80526
Location for 1-hr Rainfall Depths (use dropdown):
Workbook Protected Worksheet Protected
SDI_Design_Data_v1.08.xlsm, Design Data 12/17/2019, 11:27 AM
WQCV_Trigger = 1
RunOnce= 1
CountA=1
Draintime Coeff=1.0
0 1 2 3
#N/A
#N/A
0 1 2 3
#N/A
#N/A
Check Data Set 1 Check Data Set 1
Stormwater Detention and Infiltration Design Data Sheet
Area
Discharge
0
2
4
6
8
10
12
14
16
18
0.1 1 10
FL
O
W
[
c
f
s
]
TIME [hr]
100YR IN
100YR OUT
50YR IN
50YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
WQCV IN
WQCV OUT
0
1
2
3
4
5
6
0.1 1 10 100
PO
N
D
I
N
G
D
E
P
T
H
[
f
t
]
DRAIN TIME [hr]
100YR
50YR
10YR
5YR
2YR
WQCV
SDI_Design_Data_v1.08.xlsm, Design Data 12/17/2019, 11:27 AM
1
Ramsey Pickard
From:mailer@digitaldataservices.com
Sent:Friday, January 8, 2021 1:16 PM
To:Ramsey Pickard
Subject:Stormwater Detention and Infiltration Facility - Fort Collins Montessori School Detention
Pond
Thank you for submitting to the Colorado Stormwater Detention and Infiltration database. Your facility has been
recorded and the local jurisdiction has been notified.
Facility ID: SWDF-20210108131554
Name: Fort Collins Montessori School Detention Pond
Division: South Platte
Jurisdiction: FortCollins
Design Storm: 100-Year
Water Surface Acres: .43
Edit Key: b94ed63637c9606f510c43178bb24a92
If you wish to edit the facility in the future, you will need the Edit Key listed above. If you lose the key, you will not be
able to edit the facility information in the future.
Channel Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc.Friday, Oct 30 2020
Cross-Section A
Triangular
Side Slopes (z:1) = 4.00, 10.00
Total Depth (ft) = 0.84
Invert Elev (ft) = 5091.11
Slope (%) = 1.10
N-Value = 0.030
Calculations
Compute by: Known Q
Known Q (cfs) = 4.09
Highlighted
Depth (ft) = 0.53
Q (cfs) = 4.090
Area (sqft) = 1.97
Velocity (ft/s) = 2.08
Wetted Perim (ft) = 7.51
Crit Depth, Yc (ft) = 0.47
Top Width (ft) = 7.42
EGL (ft) = 0.60
0 2 4 6 8 10 12 14 16
Elev (ft)Depth (ft)Section
5090.75 -0.36
5091.00 -0.11
5091.25 0.14
5091.50 0.39
5091.75 0.64
5092.00 0.89
Reach (ft)
PAGE | 1
Fort Collins Montessori School
FINAL DRAINAGE REPORT
I hereby attest that this report for the final drainage design of stormwater management facilities
for the Fort Collins Montessori School site was prepared by me, or under my direct supervision,
in accordance with the provisions of the City of Fort Collins Stormwater Criteria Manual. I
understand that the City of Fort Collins does not and will not assume liability for drainage
facilities designed by others.
Ramsey J, Pickard, P.E.
Registered Professional Engineer
State of Colorado No. 56732
QUALITY
INTEGRITY
VALUE
7380 G REENDALE R OAD * W INDSOR , CO 80550 * 970.744.4731
December 9, 2022
To City of Fort Collins Staff: Matt Simpson; Basil Hamdan; Adam Camp
Re: Fort Collins Montessori School Phase I Erosion Control I SW Engineering
In formal response to the items listed by Adam Camp on October 12, 2022, and as observed by
City Staff on December 8, 2022.
North Rain Garden: The rundown and flow path had been corrected as previously requested
by the Stormwater Engineering. However, vegetation has not adequately been established over
the past several years. Follow up seeding, mulching, and soil amendment as required to
establish the vegetation is to be included the final approved MA plans & contractor’s scope of
work for Phase II construction.
West Rain Garden: Staff Verified that the forebay adjustments previously requested had been
made and that the system is functioning as intended. No further action is required here.
Site to Obtain 70% Vegetation Density: In previously seeded areas, Vegetation has not been
adequately established over the past several years. Follow up seeding, mulching, and soil
QUALITY
INTEGRITY
VALUE
7380 G REENDALE R OAD * W INDSOR , CO 80550 * 970.744.4731
amendment as required to establish the vegetation is to be included the final approved MA
plans & contractor’s scope of work for Phase II construction.
Detention Pond Depth Gauge: The height of the gauge was previously adjusted so that it is
18” above the max. depth of the pond, 6” higher than the required height. However, staff has
requested that the contractor reconstruct the post to match the City provided Details. Elder
Construction has agreed to reconstruct the post out of a single piece of 8” x 8”x 8’ treated
lumber as part of the Phase II construction project.
Civil Engineer Submits Updated Site Certification: All indications of yesterday’s walk-
through are that the stormwater system is functioning as intended. Matt Simpson requested
that the Site Certification be re-uploaded to the State SDI Tracking Portal for his acceptance.
Civil Engineer to Upload to State SDI Tracking Portal: Phase I Civil Engineer, Coffey
Engineering will re-upload the Site Certification for City of Fort Collins Acceptance.
Close Out Meeting: I’m assuming this meeting was what was held on site on December 8th,
2022, with City Staff. However, if an additional meeting is required, we will be in attendance.
Please do not hesitate to contact me if you have any additional concerns or questions.
Respectfully,
Sean Windsor
Sean Windsor
Project Manager
Elder Construction
(970) 833-5368 office
(970) 652-6047 mobile
Sean.windsor@elderconstructioninc.com
Utilities
electric · stormwater · wastewater · water
Fort Collins, CO 80522
970.212.2900
V/TDD: 711
utilities@fcgov.com
/utilities
10/12/2022
Dear Mr. Vincent,
As you are the listed contact for the escrow supplied to the city for this project, I am reaching out to you
regarding the remaining work necessary to meet the requirements for the City of Fort Collins to accept
completion of The Fort Collins Montessori School and return escrow payment. The following items
listed below would need to be addressed.
1. North Rain Garden – Verify the rundown and flow path has been corrected where the flow does
not short cut around Turf Reinforcement Mat (TRM).
2. West Rain Garden – Verify the forebay adjustments have been corrected to prevent flow bypass
3. Site to obtain 70% vegetation density. Which will require follow up seeding, mulching, and soil
amendment.
4. Detention pond depth gauge needs to be replaced to meet correct height and be installed per
the detail.
5. Civil Engineer submits updated site certification. (We recommend the Civil and City Review
Engineers set up a walk-through meeting to confirm stormwater system is functioning as
intended)
6. Civil Engineer upload to State’s Stormwater Detention and Infiltration (SDI) tracking portal for
City acceptance.
7. Close out Meeting
Our intent is to finish, closeout, and return the $10,519.50 escrow deposited by Fort Collins School
Project Fund which was provided at the start of construction and held in security to fulfill the Erosion
Control and Stormwater Engineering requirements of the Development Agreement. I have also
attached a copy of the Development Agreement between the City of Fort Collins and Fort Collins
Montessori School Building Corporation. If you have any questions please feel free to reach out to
myself or you can email Erosion@fcgov.com or WaterUtilitiesEng@fcgov.com
Thank you.
Adam Camp, Senior Construction Inspector
970-420-6963
acamp@fcgov.com