HomeMy WebLinkAboutSite Certifications - 07/11/201812/15 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
Oakridge Crossing
May 10, 2018
1605388
Yes
Yes
Yes
Yes
Yes
Yes
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.
Yes
N/A
N/A
Yes
Yes
N/A
Yes
Yes
Yes
N/A
N/A
Yes
Conc. Channel
/15 Page 3
N/A
4967.52, 4967.50
4967.50
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
CDOT Type C Inlets
Raingarden inlets for overflow
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.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
N/A
N/A
N/A
N/A
N/A
N/A
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.
Yes
Yes
Yes
Yes
Yes
Yes
Yes
N/A
N/A
N/A
N/A
N/A
Yes
Yes
Yes
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.
Yes
Yes
Yes
N/A
No
Yes
Yes
No
Yes
Yes
Yes
Yes
Yes
Yes
Yes
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.
N/A
Yes
N/A
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Yes
12/15 Page 1
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.
I.Compaction
A.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.The pipe trenches have been compacted in accordance with Section 02225-3.07.A.1. of the Fort Collins Development Construction
Standards (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. Riprap - FCSCM Vol.1, Ch.7, Sec.4.4.4.3
A.The riprap bedding is a granular bedding of the gradation and thickness indicated on the approved construction plans.
B.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.
C.The riprap is the gradation shown on the approved construction plans with a D50 of .
D.The riprap thickness is as shown on the approved construction plans and extends to the horizontal limits shown.
E.The riprap is buried to the depth indicated on the approved construction plans. (A minimum of 6 inches of soil is required.)
IV. Permanent Erosion Control Fabric - FCSCM Vol.1, Ch.7
A.All fabric was installed per manufacturer’s specifications.
V. Certification of Other Permanent BMPs - FCSCM Vol.2, Ch.8, Sec.2 & FCSCM Vol.2, Ch.12
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 and at the end of flared end sections.)
12
N/A
Yes
Yes
N/A
Yes
Yes
Yes
N/A
12/15 Page 2
Permeable Interlocking Concrete Pavers
Post-excavation infiltration rates are consistent with design
infiltration capacity (for “full or partial infiltration” designs)
Impermeable liner meets design specifications
Impermeable liner attached to concrete perimeter wall
Impermeable liner is not exposed
Any penetrations of the impermeable liner have been sealed
and checked for water-tightness.
Meets specifications for:
-Dimensions
-Reinforcement
-Footings
Underdrain pipe is per design specifications
At least one cleanout is provided per underdrain lateral
Cleanout pipe is not perforated
Cleanout covers are installed and watertight
Underdrain is NOT wrapped in geotextile fabric
Underdrain orifice plate installed at outlet structure
Underdrain integrity tested after backfilling using TV and/or
water test
Base coarse (e.g., #2/4) has 90% fractured faces
Bedding coarse (e.g., #89) is thoroughly washed
Sub-base materials are installed and compacted according to
manufacturer’s specifications
PICP area is protected from construction site sediment,
including runoff from the upstream catchment and
Close Out
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12/15 Page 3
Bioretention Cells
Heavy equipment did not travel over bioretention cell during
excavation
Bottom of cell was “ripped” after excavation Photograph before/after “ripping”
Bottom of cell is flat and level Photograph
Excavated area is protected/surrounded by sediment/runoff
control BMPs during construction
Photograph
Overflow inlet elevation is set above bioretention media per
plan (typically 12 inches)
Overflow inlet invert elevation is at least 3 inches below
containment wall/berm (to direct overflow into inlet)
Measure/record distance between inlet and top of
containment wall/berm
Upstream catchment drains to inlet
Forebay is installed according to design specifications
Forebay has flat, concrete bottom
Outlet structure/overflow elevation is confirmed Measure/record distance from overflow to top of media
filter
Impermeable liner meets design specifications
Impermeable liner attached to concrete perimeter wall
Impermeable liner is not exposed
Underdrain pipe is per design specifications
At least one cleanout is provided per underdrain lateral
Cleanout pipe is not perforated
Cleanout covers are installed and watertight
Underdrain is NOT wrapped in geotextile fabric
Underdrain orifice plate installed at outlet structure
Underdrain integrity tested after backfilling using TV and/or
water test
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G G G
E E
T
GM
4025 Automation Way, Suite C4
Fort Collins, CO 80525
970-232-9645
www.WashburnSurveying.com
Sheet 1 of 1 Project #: 2017-0019 Date: April 19, 2018 Scale: 1"=20' Drawn: CDBSheet 1 of 1 Project #: 2017-0019 Date:
Sc
a
l
e
:
1
"
=
2
0
'
SITE AS-BUILT
OAKRIDGE CROSSING
LOT 1 OAKRIDGE BUISNESS PARK 40TH FILING, LOCATED IN THE NORTHEAST QUARTER OF SECTION 6, TOWNSHIP 6 NORTH, RANGE
68 WEST OF THE 6TH P.M., CITY OF FORT COLLINS, COUNTY OF LARIMER, STATE OF COLORADO
ELEVATIONS SHOWN ARE FROM AN AS-BUILT SURVEY OF THE SITE
PERFORMED ON MARCH 2ND, APRIL 19TH AND MAY 4TH, 2018
CHAD R. WASHBURN
COLORADO LICENSED PROFESSIONAL LAND SURVEYOR 37963
FOR AND ON BEHALF OF WASHBURN LAND SURVEYING, LLC.
970.232.9645