HomeMy WebLinkAboutSite Certifications - 03/06/201912/15 Page 1
OVERALL SITE and DRAINAGE CERTIFICATION
Commercial, Multi-Family and Subdivision Certification Form and Checklist
Project Name:
Date:
Building Permit Numbers:
(Commercial or multi-family)
Per the requirement in Fort Collins Stormwater Criteria Manual (FCSCM) Volume 1, Section 6.11, please fill in
all applicable items in this Certification Form for Commercial, Multi-Family and Overall Single Family sites.
NOTE: several items must be verified during construction. A copy of the approved grading plan must be
submitted with the as-built grading plan. (As-built elevations must be written in red next to the approved
elevations.)
•Use “Yes” for items completed as described.
•Use “N/A” for items that are not applicable to the site being certified.
•If any blanks are “No,” attach an explanation referencing the item number below.
Attach an explanation or description of the as-built condition for any items listed or for anything not listed but
shown on the approved construction plans.
Provide an as-built redline or Mylar drawing with the following:
I.Water Quality and Quantity Detention Basin Certification - FCSCM Vol.2, Ch.10
For multiple detention basins on a site, provide the following for each basin separately:
A. Volume: As-built topographic verification is attached at 1-foot (or less) contour intervals and
volume verification calculations for the water quality capture volume and the 100-year detention storage
volume.
1. Detention basin topography was prepared by a professional land surveyor registered in the state
of Colorado.
2.Both proposed and as-built contours are shown on the same plan sheet (dashed lines for
proposed and solid lines for as-built).
3.All critical spot elevations as shown on the approved construction plans have been verified and
the as-built elevations are shown on the plan sheet.
4.Stage-storage-discharge tables are provided on a separate document.
5.Verification that designed drain time is in compliance with Colorado Revised Statute § 37-92-
602(8) is attached and has been uploaded to the Statewide Compliance Portal
(tinyurl.com/COCompliancePortal) for approval. Uploaded documents must include:
a.The cover sheet from the approved drainage report
b.The stamped certification page from the approved drainage report
c.As-built topographic survey
d.Stamped certification page from the Overall Site & Drainage Certification
e.PDF output from the Stormwater Detention and Infiltration Design Data Speadsheet
Erik Snyder PLS 38555
12/15 Page 2
B.Water Quality and Quantity Detention Basin Grading: Attached is as-built verification that there is
a minimum 2% positive fall into the concrete trickle pans or flow-line(s) from all areas in the bottom of
the detention pond. If there is a “soft pan” in the flow-line, all areas still must meet the minimum 2%
grade requirement.
1.Low Flow: Choose one of the following detention basin low flow options as applicable:
a. Turf swale for low flow path in detention basin.
There is a minimum 2% grade in the flow-line(s) of the detention basin. The flattest as-built grade
is .
b.Concrete pan for low flow in detention basin.
There is a concrete pan installed that meets the grades as shown on the approved construction
plans. (Show as-built spot elevations.)
c.Soft pan for low flow in detention basin.
•Verify and document the soft pan material gradation, trench width and depth - to be verified
during construction by engineer. Picture documentation is preferred or engineer’s statement of
visual inspection and compliance. (Choose one below.)
o There is a soft pan with an underdrain installed that meets the design on the approved
construction plans. (Show the underdrain grades, bedding material, geotextile, spot elevations,
bends, cleanouts, etc.)
o There is soft pan installed without an underdrain but there is a type A or B soil. The soil
type must be documented by supplying verification from a registered professional geotechnical
engineer.
NOTE: Spot elevations are to be within 0.2 ft. +/-.
2. Side Slopes: The as-built side slopes of the detention basin have been calculated and are shown.
Indicate the side slope with an arrow and a numerical value (e.g., 6.25:1). The maximum slope allowed
is 4:1. Small areas of 3:1 may be acceptable, but slopes steeper than 3:1 must be stabilized or re-
graded. Provide documentation if a variance was granted for steeper slopes during the design process.
3.Spillway Certification: The following items must be field verified:
a.The location of the spillway is indicated on the as-built plan.
b.The width of the spillway is indicated on the as-built plan.
c.The elevation(s) of the spillway is shown on the as-built plan.
d.A concrete ribbon defines the location and grade of the spillway.
e.There is downstream scour protection in the spillway as per the construction plans. Indicate
type: (riprap size “D50” gradation and bedding type, geotextile, buried
riprap with inches of bury, etc.).
f.There are no obstructions in the spillway, such as trees, bushes, sidewalks, landscape
features, rocks, etc.Spillway for pond is over a sidewalk and landscape with a 2-6% slope. No
scour is expected during overflow event
0.5% for about 25'
Garage is 0.35' above overflow weir and 0.85' above 100-year WSEL. In an
event where overflow weir is breached, stormwater may get in garage (through
trench drain) if overflow weir is flowing fuller than 0.35' high
Some areas have greater than +/- 0.2 ft change in grade.
Grading concept and functionality is still compliant with intent of
plans.
12/15 Page 3
4.Outlet Structure Certification
a.The orifice plate for the approved release rate is installed with the correct size and location of
the orifice.
b.The orifice plate for the water quality outlet is installed with the correct hole size, number of
rows and columns of holes.
c.The bottom hole on both the water quality and quantity outlets are at the bottom of the plate
so no water ponds in front of the plate.
d.The well screen is the correct material and is installed as shown on the construction plans.
e.100-year overflow grate elevation is . (Elev. A on detail D-46)
f.The top elevation of the water quality capture volume is . (Elev. B on detail
D-46)
g.Overflow grate is made of the correct material, has the correct bar spacing, is hinged at the
top and bolted at the bottom.
h.The bottom of the outlet box has no obstructions or misalignments that will cause it to retain
runoff water and is sloped at 2% towards outlet.
II.Channels/Swales - FCSCM Vol.1, Ch.7, Sect.3&4
A. Capacity: The as-built capacity of all the major channels and swales has been verified. They meet
or exceed capacity requirements shown in the approved drainage study for this project.
1.All swales are located within the drainage easements as shown on the construction plans.
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.
3.As-built spot elevations on channels/swales are shown that correspond to spot elevations
shown on the approved construction plans.
4.All permanent erosion control measures are installed as shown on the approved construction
plans (e.g., drop structures, riprap, TRMs, etc.). (Include pictures and verification of the materials used
as part of this verification.)
5.All pans, curbs, storm pipes or other appurtenances appropriately tie into each other in the
system. (Pictures at tie-in points suggested.)
6.The minimum freeboard is provided for all channels and swales as shown on the approved
construction plans or as identified in the approved drainage study. (Show the freeboard provided on
the cross-sections as on the construction plan set or attached as separate documentation.)
7.The low flow portion of all channels or swales is clear of obstructions. (No landscaping, trees,
shrubs, sod, etc. infringe on the low flow portion of channels or swales.)
B
TRMs at FES have not been installed yet. These are scheduled to be
installed by the erosion control contractor.
An additional hole (1/2 size) was added at bottom of plate for drainage
1.5%
long.
slope
12/15 Page 4
III.Storm Pipes (aka storm drains) - FCSCM Vol.1, Ch.6, Sec. 4
A. Storm Drain Pipe Capacity: The as-built capacity of all pipes installed on this project has been
verified and meets or exceeds the capacity requirements shown in the approved drainage study for this
project.
1.All storm drain pipe sizes and materials have been verified and are in conformance with the
approved construction plans. (Indicate on the plan and profile sheets that they have been verified.)
Material and size substitutions must be approved prior to installation. If a pipe size or material was
changed during construction, the certification engineer must attach the approval documents or supply
them with this certification. Approval documents must include a calculation documenting the capacity
equivalency (equal or greater) of the substituted size.
2.The longitudinal slope of the pipe is as shown on the approved construction plans. The
acceptable minimum slope is 0.4%. All slopes flatter than the designed slope on the construction plans
must be justified with capacity calculations on an attached sheet.
3.The as-built invert elevations have been verified and are shown on the plan and profile sheets of
the approved construction plans.
B.Storm Drain Pipe Installation Requirements: All pipes are installed in accordance with the
approved construction plans.
1.The minimum cover requirements for all pipes have been met as shown on the approved
construction plans. These will be called out in critical locations.
2.All encasements and clearances as specified on the approved construction plans have been met.
3.Any specific joint types or construction methods specified on the approved construction plans
have been met. (List on a separate sheet and attach to this certification.)
IV.Concrete Pans - FCSCM Vol.1, Ch.7, Sec.4.1.3.4
A. Construction/Installation: All concrete pans have been constructed in accordance with the
approved construction plans.
1.The concrete pans are the correct size/width as shown on the approved construction plans.
2.The longitudinal slopes of the pans are as shown on the approved construction plans. The
certification engineer must justify or mitigate longitudinal slopes less than the minimum of 0.4% unless
a flatter slope was approved and is shown on the approved construction plans. Provide mitigation or
justification by separate document.
3.The cross-section of the pan is as shown on the construction plans. (Specifically, the pan cross-
section is “V” shaped and meets the side slope shown on the detail.)
4.The concrete pans are a minimum of 6 inches thick without reinforcement and a minimum of 4
inches thick with a minimum of 6X6-W14xW14 reinforcement per detail D20B and D20C. (Provide
documentation of the reinforcement used if different than shown on the details or on the approved
construction plans.)
5.The spot elevations shown on the concrete pan(s) have been verified and are shown on the as-
built drawings.
Some small horizontal and vertical deviations from plans. Not
expected to be an issue.
Some small horizontal and vertical deviations from plans. Not
expected to be an issue.
No pans proposed with this site. Curbline meets construction plans
100-year overflow weirs in Inlet B2 and STMH C2 were modeled due to
changes in weir height.
12/15 Page 5
V. Storm Drain Inlets - FCSCM Vol.1, Ch.6, Sec. 3
A. Construction/Installation: All storm drain inlets have been constructed in accordance with the
approved construction plans.
1.The size and type of inlets are consistent with the inlets shown on the approved construction
plan. Indicate by writing “Verified” on each inlet on the plan sheet or list on a separate document the
inlet number(s), type and size (length). If the inlet installed is other than the one on the approved
construction plan detail sheet, provide the name and source of the detail with justification for equal or
better capacity.
2.The size of the inlet opening is consistent with the approved detail. (Check height and width.)
3.The elevation of the grate (if applicable) is at the elevation shown on the street profile or as
indicated by a spot elevation on the construction plans.
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.
5.The as-built size of the inlet box is as shown on the construction plans or an explanation or
justification is attached.
6.All inlet covers are stenciled or stamped with the following designation: NO DUMPING – DRAINS
TO POUDRE RIVER.
VI.Culverts - FCSCM Vol.2, Ch.9
A. Construction/Installation: All culverts have been constructed and/or installed in accordance with
the approved construction plans.
1.All culvert sizes have been verified as indicated on the as-built construction plans as correct.
2.The culvert material type for all culverts installed is as on the approved construction plans and is
indicated on the as-built plans.
3.The as-built invert “in and out” elevations have been verified and are indicated on the as-built
construction plans.
4.The culvert headwalls or wing walls have been installed as shown on the approved construction
plans. Headwalls or wing walls may be needed in the as-built conditions onsite if the slopes adjacent to
the culvert are greater than 4:1. Please note areas needing stabilization in the certification narrative.
An alternative to consider is a turf reinforcement mat (TRM).
VII.Sub-Drains
A. Construction/Installation: All sub-drains shown on the construction plans have been installed in
accordance with those plans. Sub-drains installed with the sanitary sewer are to be verified on the
sanitary sewer plan and profile sheets of the construction plans. (NOTE: Indicate any sub-drains installed
after the plans were approved on the as-built plans.)
1.The size of the sub-drains are as approved on the construction plans and are indicated on the as-
built plans.
2.The type of sub-drain, in particular the perforated and non-perforated sections of the drain, are
as indicated on the approved construction plans.
No groundwater subdrains were installed on this site. An underdrain was installed for the
Stormtech system. Underdrain has positive fall to pond. Underdrain installed at approximately
same elevation as Stormtech chambers (+0.5' higher than design). This should function
sufficiently.
12/15 Page 6
3.The cover requirements per the construction plans are provided.
4.The cleanouts have been installed at the locations shown on the construction plans and are
accessible for cleaning. (Cleanouts can be buried a maximum of 6 inches deep with their locations
marked.)
5.The backfill materials for sub-drains are as shown on the approved construction plans. (This
includes the type, depth and width.)
6.The geo-textile liner completely wraps the sub-drain and the permeable backfill material unless
shown otherwise on the approved construction plans. (Sub-drain pipe wrapped in a sock filter material
is accepted only if approved prior to installation.)
VIII.Curb Cuts
A. Construction: All curb cut openings are constructed in accordance with the approved construction
plans.
1.The size (width) of the curb cut opening is as shown on the approved construction plans.
2.The curb cut openings tie into a downstream swale, pipe, or other appurtenances with a smooth
transition and there no obstructions such as riprap or sod impeding the flow downstream of the curb
cut.
IX.Sidewalk Culverts & Chases
A. Construction/Installation: All sidewalk culverts have been installed at the locations shown on the
approved construction plans.
1.The size (width and length) of the culverts are as shown on the approved construction plans.
2.The cover plate is a minimum 5/8-inch galvanized plate bolted to a galvanized angle iron per the
detail shown on the approved construction plans or per the City’s detail.
3.The sidewalk culvert invert “in and out” elevations have been verified and are indicated on the
as-built plans.
4.The sidewalk culvert opening is as shown on the approved construction plans or per the City’s
detail.
5.There is a smooth transition both on the inlet and outlet ends of the sidewalk culvert with no
obstructions such as riprap or sod impeding the flow into or out of the sidewalk culvert.
X. Site Grading
A. Construction: All common open spaces have been graded in accordance with the approved
construction plans.
1.The grading on all common open spaces bordering private lots has been verified as correct and
the as-built rear lot corner elevations have been shown on the as-built plans.
Culvert looks to be installed 0.5' high. Drainage grade through culvert looks to be satisfactory.
Stormtech subdrain does not indicate a sock required.
12/15 Page 7
2.The as-built contours for “overlot grading” are shown on the as-built construction plans for all
common open spaces, tracts, outlots, etc. If not in compliance, please attach a narrative describing the
situation for noncompliance and when it may be corrected. An escrow for overlot grading may be
required. (NOTE: Residential Lot Grading Certification is a separate process from this Overall Site
Certification. It is understood that residential lots will be brought to final grade once the foundation is
backfilled so they may be lower than the plan shows at this Overall Site Certification stage.)
3.All turf reinforcement mats (TRMs) have been installed as shown on the approved construction
plans and the slopes are stabilized.
XI.Riprap - FCSCM Vol.1, Ch.7, Sec.4.4.4.3
A. Construction: All riprap has been installed in the locations and sizes indicated on the approved
construction plans.
XII.Permanent Erosion Control Fabric - FCSCM Vol.1, Ch.7
A. Construction: All fabric has been installed in the locations and sizes indicated on the approved
construction plans.
1.All fabric was installed per the details on the approved construction plans.
XIII.Post-Construction Site Cleanup - FCSCM Vol.3, Ch.7
A. Construction: All construction debris and obstructions of any kind have been removed from
drainage paths.
1.All construction debris has been removed except in staging area(s).
2.All ruts have been smoothed out in all construction areas.
3.All areas needing reseeding have been identified and future stabilization goals have been
coordinated with the Erosion Control Inspector and in accordance with FCSCM Vol.2 Chapter 12. Note
the area needing stabilization in the narrative.
XIV.Certification of Other Permanent BMPs - FCSCM Vol.2, Ch.8, Sec.2 & FCSCM Vol.2, Ch.12
A.The construction of channel drop structures is in accordance with the approved plan both in
location, horizontal dimensions and cross-section.
XV.Certification of LID and Water Quality Facilities - FCSCM Vol.3, Ch.4
A.Attached are the During Construction Inspection Checklist for Low Impact Development (LID) and
other items to be verified during construction, along with pictures and other required documentation.
ECB does not look to be installed on Pond side slopes. This
may not be an issue since no runoff will be directed over pond
sideslope. Pond side slope is 4:1. Ponds show no signs of
rilling or erosion on the side slope at the time of this
certification.
No seeding has occurred at the time of this certification. This will be escrowed.
TRMs have not been installed yet. These are scheduled to be
installed by the erosion control contractor.
Stormtech was installed approximately 8 feet east of design location due to utility conflicts. This puts
Stormtech eastern edge under garden retaining wall. Contractor was asked to contact Stormtech
manufacturer to verify Stormtech will be functional next to wall. Contractor indicated that Stormtech had no
concern about the relocation.
1/19 Page 1 of 2
DURING CONSTRUCTION INSPECTION CHECKLIST
To be completed by Construction Superintendent
This checklist is to be completed during construction and included with the Overall Site and Drainage Certification.
• Use “Yes” for items completed as described.
• Use “N/A” for items that are not applicable to the site being certified.
• If any blanks are “No,” attach an explanation referencing the item number below.
Project Name: Village Cooperative of Fort Collins Date: 3/6/2019
Building Permit Numbers: B1701509
I. Compaction
A. Yes All berms and embankments meet the compaction requirements as specified in the project geotechnical report or comply with the
City’s standard, which is “soils should be compacted within a moisture content range of 2% below to 2% above optimum moisture content
and compacted to 95% of the Maximum Standard Proctor Density (ASTM D698).” Compaction requires verification during construction.
Provide testing log from contractor/engineer.
II. Storm Drain Pipe Installation Requirements
A. Yes The pipe trenches have been compacted in accordance with Section 02225-3.07.A.1. of the Fort Collins Development Construction
Standards for Water, Wastewater, Stormwater (e.g., the trenches in the roadways are to be 95% of maximum density and all other areas
are to be at 90%, both in accordance with ASTM D698).
III. Energy Dissipation and Erosion Protection - FCSCM Chapter 9, Section 7.0
A. Riprap
1. N/A The riprap bedding is a granular bedding of the gradation and thickness indicated on the approved construction plans.
2. N/A A filter fabric was installed instead of granular bedding and is the material shown on the approved construction plans or was an
approved equal. Provide documentation for an approved equal.
3. N/A The riprap is the gradation shown on the approved construction plans with a D50 of .
4. N/A The riprap thickness is as shown on the approved construction plans and extends to the horizontal limits shown.
5. N/A The riprap is buried to the depth indicated on the approved construction plans. (A minimum of 6 inches of soil is required.)
B. Permanent Erosion Control Fabric - FCSCM Vol.1, Ch.7
1. N/A All fabric was installed per manufacturer’s specifications.
1/19 Page 2 of 2
IV. Other Permanent BMPs
A. N/A All cut-off walls have been installed in accordance with the approved construction plans. (Cut-off walls are required for irrigation ditch
crossings of storm drain pipes.)
V. Extended Detention Basins
A. Yes Installation of this facility was verified via inspection by a City-Stormwater Inspector at the point of installation of the water quality
control box(es). Provide date of inspection and name of inspector: December of 2018 Kurt Vanatta
Included certification sheet(s):
Please check the appropriate box(es) for the Low Impact Development
(LID) facilities found on this site and complete the corresponding
certification sheets.
☐ Permeable Interlocking Concrete Pavers
☐ Bioretention Cells (Rain Gardens)
☐ Sand Filters
☐ Vegetated Buffers
☒ Underground Infiltration
☐ Other LID – For certification of Dry Wells, Tree Filters,
Constructed Wetland Channels & Ponds, etc., contact City Staff
to determine requirements to exhibit the LID facility has been
constructed and functions as intended per the approved
drainage report.
*Please provide photographic documentation of the installation of all
stages of all LID facilities.
**Please contact the City Stormwater Inspector at
stormwaterinspection@fcgov.com to discuss inspection requirements
for each LID facility and request inspections.
***All facilities being certified must be “clean” – free of sediment &
construction debris – prior to certification or acceptance of the facility.
Completed by:
Name: Thom Dobeck
Title: Superintendent
Email: Thom@halcyonconstruction.org
Phone: 970-652-0731
Company: Halcyon Construction Inc.
Address: 4627 W. 20th St Rd, Ste B, Greeley, CO. 80634
1/19 Page 1 of 2
Underground Infiltration
Item/Activity Yes No N/A Submittal Requirements Submitted?/Response
Stormwater Inspection
Manufacturer’s representative pre-construction meeting: A
pre-construction meeting was completed with the
manufacturer’s representative and installers
☒ ☐ ☐
Record date and who was present at the
meeting
Pre-construction meeting was held with City-Stormwater
Inspector to discuss installation, inspection, checklist, and
protection from sedimentation
☒ ☐ ☐
Record date, inspector name, meeting
location (i.e. DCP, initial erosion control
inspection, etc.)
Inspection(s): Installation of this facility was verified via
inspection by a City-Stormwater Inspector at the point at which
the chambers had been laid/prior to backfilling.
Correct fabric placement was confirmed.
☒ ☐ ☐
Record date(s) of inspection and
inspector’s name
Excavation
Heavy equipment did not travel across underground cell area
during excavation (prevents over-compaction) ☒ ☐ ☐
Bottom of cell was “ripped” after excavation ☒ ☐ ☐ Provide photographs before and after
“ripping”
Photos provided to
Northern Engineering
Bottom of cell is flat and level, or graded per approved grading
plans ☒ ☐ ☐ Provide photograph Photos provided to
Northern Engineering
Non-woven fabric is installed per manufacturer’s specifications
and was not damaged during construction (around system) ☒ ☐ ☐ Provide photograph Photos provided to
Northern Engineering
Woven fabric is installed per manufacturer’s specifications and
was not damaged during construction (beneath chambers) ☒ ☐ ☐ Provide photograph Photos provided to
Northern Engineering
Excavated area is protected/surrounded by sediment/runoff
control BMPs during construction ☒ ☐ ☐ Provide photograph Photos provided to
Northern Engineering
Impermeable Liner
Impermeable liner meets design specifications ☒ ☐ ☐ Provide specifications of delivered
material
Impermeable liner is not exposed ☒ ☐ ☐
Any penetrations of the impermeable liner have been sealed
and checked for water-tightness. ☒ ☐ ☐ Provide photograph (if necessary)
Aggregate
Foundation and embedment materials are installed and
compacted according to design and manufacturer’s
specifications
☒ ☐ ☐
Provide load ticket and photograph(s)
Underdrain System
1/19 Page 2 of 2
Underdrain pipe meets design specifications ☒ ☐ ☐ Provide photograph
At least one cleanout is provided per underdrain lateral ☒ ☐ ☐ Provide photograph
Cleanout pipe is solid (not perforated/slotted) ☒ ☐ ☐ Provide photograph
Cleanout covers are installed and watertight ☒ ☐ ☐ Provide photograph
Verify the underdrain is NOT wrapped in geotextile fabric ☒ ☐ ☐ Provide photograph
Verify there is no orifice plate on the underdrain outfall ☒ ☐ ☐ Provide photograph
Underdrain integrity tested after backfilling using TV and/or
water test ☒ ☐ ☐ Provide documentation of test results
Manifold system
Overflow weir elevation is set at/above water quality storm
elevation ☒ ☐ ☐ Record weir elevation on survey
Maintenance access is provided for each Isolator Row ☒ ☐ ☐
At least one inspection port has been provided for each Isolator
Row (located in middle third of each row) ☒ ☐ ☐
Upstream catchment drains to inlet/intake properly ☒ ☐ ☐
Underground Detention Chambers
All chambers were installed per approved Utility Plans and
manufacturer’s specifications ☒ ☐ ☐ Photograph
Close Out
Upstream catchment is stabilized prior to diverting runoff into
Underground Detention system ☒ ☐ ☐
All Isolator Rows, chambers, and pipes are cleaned and
sediment/debris has been removed ☒ ☐ ☐
FO FO FO FO FO FO FO FO FO FO FO FO
GGGGGGGGGGGG
SS SS SS SS SS SS SS SS SS SS SS SSS
T T T T T
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TF
HORSETOOTH ROAD
VILLAGE COOPERATIVE OF
FORT COLLINS
DETENTION POND
PROPOSED100-YR WSEL: 5006.31
INSTALLED 100-YR WSEL: 5006.40
VILLAGE COOPERATIVE OF F.C.
SHEET NO:
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ISSUED:DRAWING REFERENCE:
RECORD DRAWING
POND STORAGE
DRAINAGE
CERTIFICATION
S. THOMAS
1in=30ft
MARCH 1, 2019 N/A
DRAWN BY:
SCALE:
ISSUED:
( IN FEET )
0
1 INCH = 30 FEET
30 30
FORT COLLINS: 301 North Howes Street, Suite 100, 80521
GREELEY: 820 8th Street, 80631
E N G I N E E R N GI
EHTRON R N
970.221.4158
northernengineering.com
Detention Pond
Contour
Elevation
(Y-values)
Contour
Area
Incremental
Volume
Total
Volume
ft2 ft3 ft3
5,000.80 15 0 0
5,001.00 284 30 30
5,001.20 475 86 116
5,001.40 651 135 251
5,001.60 842 185 437
5,001.80 1,079 238 675
5,002.00 1,421 290 965
5,002.20 1,713 339 1,304
5,002.40 1,930 383 1,687
5,002.60 2,135 423 2,110
5,002.80 2,354 465 2,575
5,003.00 2,579 509 3,084
5,003.20 2,825 555 3,639
5,003.40 3,083 605 4,244
5,003.60 3,351 657 4,901
5,003.80 3,635 712 5,612
5,004.00 3,931 769 6,381
5,004.20 4,241 829 7,210
5,004.40 4,567 892 8,102
5,004.60 4,911 958 9,061
5,004.80 5,275 1,029 10,090
5,005.00 5,665 1,104 11,193
5,005.20 6,103 1,186 12,379
5,005.40 6,591 1,278 13,657
5,005.60 7,153 1,383 15,040
5,005.80 7,875 1,511 16,551
5,006.00 8,999 1,695 18,246
5,006.20 10,506 1,957 20,203
5,006.40 11,046 2,164 22,366
5,006.60 11,626 2,276 24,642
5,006.80 12,257 2,397 27,039
100-year Volume Required (cf)22,329
100-year WSEL Proposed 5006.31
100-year WSEL Installed 5006.40
WQ Volume Required (cf)740
WQ WSEL Proposed 5001.71
WQ WSEL Installed 5001.84
Weir Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, Feb 21 2019
100-yr Overflow Weir in Inlet B2
Rectangular Weir
Crest = Sharp
Bottom Length (ft) = 3.00
Total Depth (ft) = 2.00
Calculations
Weir Coeff. Cw = 3.33
Compute by: Known Q
Known Q (cfs) = 16.00
Highlighted
Depth (ft) = 1.37
Q (cfs) = 16.00
Area (sqft) = 4.11
Velocity (ft/s) = 3.90
Top Width (ft) = 3.00
0 .5 1 1.5 2 2.5 3 3.5 4
Depth (ft) Depth (ft)100-yr Overflow Weir in Inlet B2
-1.00 -1.00
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Length (ft)Weir W.S.
Weir Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, Feb 21 2019
100-yr Overflow Weir in STMH C2
Rectangular Weir
Crest = Sharp
Bottom Length (ft) = 1.50
Total Depth (ft) = 2.00
Calculations
Weir Coeff. Cw = 3.33
Compute by: Known Q
Known Q (cfs) = 3.82
Highlighted
Depth (ft) = 0.84
Q (cfs) = 3.820
Area (sqft) = 1.25
Velocity (ft/s) = 3.05
Top Width (ft) = 1.50
0 .5 1 1.5 2 2.5
Depth (ft) Depth (ft)100-yr Overflow Weir in STMH C2
-1.00 -1.00
0.00 0.00
1.00 1.00
2.00 2.00
3.00 3.00
Length (ft)Weir W.S.
Weir Report
Hydraflow Express Extension for Autodesk® AutoCAD® Civil 3D® by Autodesk, Inc. Thursday, Feb 21 2019
Allowable Flow Over Weir before Trench Drain Pools and Water goes to Parking Structure
Trapezoidal Weir
Crest = Sharp
Bottom Length (ft) = 20.00
Total Depth (ft) = 0.60
Side Slope (z:1) = 4.00
Calculations
Weir Coeff. Cw = 3.10
Compute by: Known Q
Known Q (cfs) = 12.00
Highlighted
Depth (ft) = 0.33
Q (cfs) = 12.00
Area (sqft) = 7.04
Velocity (ft/s) = 1.71
Top Width (ft) = 22.64
0 5 10 15 20 25 30 35
Depth (ft) Depth (ft)Allowable Flow Over Weir before Trench Drain Pools and Water goes to Parking Structure
-0.50 -0.50
0.00 0.00
0.50 0.50
1.00 1.00
Length (ft)Weir W.S.
FINAL DRAINAGE AND
EROSION CONTROL REPORT
May 30, 2017
The Village Cooperative of Fort Collins
Fort Collins, Colorado
Prepared for:
Village Cooperative of Fort Collins
Shane Wright
1400 Corporate Center Circle, Suite 100
Eagan, Minnesota 55121
651-760-8306
Prepared by:
301 N. Howes Street, Suite 100
Fort Collins, Colorado 80521
Phone: 970.221.4158
www.northernengineering.com
Project Number: 1284-001
This Drainage Report is consciously provided as a PDF.
Please consider the environment before printing this document in its entirety.
When a hard copy is absolutely necessary, we recommend double-sided printing.
RE: Final Drainage and Erosion Control Report for
The Village Cooperative of Fort Collins
Dear Staff:
Northern Engineering is pleased to submit this Final Drainage and Erosion Control Report for your
review. This report accompanies Final Development Plan submittal for the proposed The Village
Cooperative of Fort Collins development.
This report has been prepared in accordance to Fort Collins Stormwater Criteria Manual (FCSCM),
and serves to document the stormwater impacts associated with the proposed project. We
understand that review by the City is to assure general compliance with standardized criteria
contained in the FCSCM.
If you should have any questions as you review this report, please feel free to contact us.
Sincerely,
NORTHERN ENGINEERING SERVICES, INC.
Stephanie Thomas, PE
Project Engineer
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-to-Width Ratio =2.00 L:W 0.00 15 0.00 0.00
Watershed Area =2.73 acres 0.20 284 0.20 0.21
Watershed Imperviousness =58.0%percent 0.40 475 0.40 0.29
Percentage Hydrologic Soil Group A =percent 0.60 651 0.60 0.36
Percentage Hydrologic Soil Group B =25.0%percent 0.80 842 0.80 0.42
Percentage Hydrologic Soil Groups C/D =75.0%percent 1.00 1,079 1.00 0.46
1.20 1,421 1.20 0.51
1.40 1,713 1.40 0.55
1.60 1,930 1.60 0.59
1.80 2,135 1.80 0.62
User Input: Detention Basin Characteristics 2.00 2,354 2.00 0.66
WQCV Design Drain Time =12.00 hours 2.20 2,579 2.20 0.69
2.40 2,825 2.40 0.72
2.60 3,083 2.60 0.75
2.80 3,351 2.80 0.78
3.00 3,635 3.00 0.81
3.20 3,931 3.20 0.83
3.40 4,241 3.40 0.86
3.60 4,567 3.60 0.88
3.80 4,911 3.80 0.91
4.00 5,275 4.00 0.93
4.20 5,665 4.20 0.95
4.40 6,103 4.40 0.98
4.60 6,591 4.60 1.00
4.80 7,153 4.80 1.02
5.00 7,875 5.00 1.04
5.20 8,999 5.20 1.06
5.40 10,506 5.40 1.08
5.60 11,046 5.60 1.10
5.80 11,626 5.80 1.12
After completing and printing this worksheet to a pdf, go to:6.00 12,257 6.00 1.14
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 25 Year 50 Year 100 Year
Two-Hour Rainfall Depth =0.53 0.98 1.36 1.71 2.31 2.91 3.67 in
Calculated Runoff Volume =0.041 0.123 0.200 0.273 0.411 0.540 0.717 acre-ft
OPTIONAL Override Runoff Volume =acre-ft
Inflow Hydrograph Volume =0.041 0.122 0.200 0.273 0.410 0.540 0.716 acre-ft
Time to Drain 97% of Inflow Volume =1 3 4 5 6 7 9 hours
Time to Drain 99% of Inflow Volume =2 3 4 5 6 8 9 hours
Maximum Ponding Depth =0.98 2.21 3.06 3.68 4.61 5.25 5.89 ft
Maximum Ponded Area =0.024 0.059 0.085 0.108 0.151 0.215 0.273 acres
Maximum Volume Stored =0.012 0.066 0.126 0.187 0.305 0.419 0.579 acre-ft
Stormwater Detention and Infiltration Design Data Sheet
Village Cooperative of Fort collins
Fort Collins, CO
Workbook Protected Worksheet Protected
Village Cooperative - State Statute Compliance .xlsm, Design Data 3/1/2019, 11:04 AM
Doing_Clear_Formatting =Yes
CountA=1
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
25YR IN
25YR OUT
10YR IN
10YR OUT
5YR IN
5YR OUT
2YR IN
2YR OUT
WQCV IN
WQCV OUT
0
1
2
3
4
5
6
7
0.1 1 10 100
PO
N
D
I
N
G
D
E
P
T
H
[
f
t
]
DRAIN TIME [hr]
100YR
50YR
25YR
10YR
5YR
2YR
WQCV
Village Cooperative - State Statute Compliance .xlsm, Design Data 3/1/2019, 11:04 AM