HomeMy WebLinkAboutSite Certifications - 01/13/2022Page 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) Chapter 3, Section 3.0 to certify as-
built construction to the approved drainage and grading plans, 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 - FCSCM Ch. 6 and 7
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
11/19
Hickory Commons
12/8/2021
P1500002, B1702913 (321 Hickory St), B1810610 (331 Hickory St), B1916565 (325 Hickory St)
Yes
Yes
No
Yes
Yes
No
The pond is designed with
mainly as a water quality
with a 40-hr drain time.
Post asbuilt survey, the pond side slopes were adjusted to reduce the slope and the top of berm was
raised approximately 12". All of the required volumes were achieved with the grading as presented in the
asbuilt survey. These adjustments are not reflected in the asbuilt survey, though the reduced slope and
raised berm increased the volumes from what was previously surveyed. Since these adjustments would
increase the pond volumes, the survey was not updated.
No items were verified
during construction by an
engineering consultant
Wes Lamarque
1/13/2022
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: 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.
11/19
Yes
Yes
1.5%
N/A
N/A
Yes
No
No
Yes
No
No
Yes
Grading was adjusted post survey. Side slopes were adjusted measured in the field. All side slopes are
approximately 3:1 with exception to the area in immediate vicinity of the outlet structure.
The spillway is the south
end of the entry drive
2.0% was not achieved but positive drainage is provided to the outlet.
Page 3
4.Outlet Structure:
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 Ch. 8, Sec. 2.0 and Ch. 9, Sec. 5.0
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.)
11/19
N/A
Yes
Yes
Yes
Yes 4974.0
Yes 4972.8
Yes
Yes
N/A
Elev. C?
The grate is removable and secured but is not hinged.
Per approved revisions, grading was adjusted and trail acts as drainage path
Page 4
III.Storm Pipes (aka storm drains) - FCSCM Ch. 9, Sec. 4.0
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 and construction specifications.
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 Ch. 8, Sec. 2.0
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.
11/19
Yes
No
Yes
No
N/A
N/A
(Private on site storm only)
Asbuilt slopes match or exceed design slopes
(Private on site storm only)
Installation was not observed during construction
Page 5
V. Storm Drain Inlets - FCSCM Ch. 9, Sec. 3.0
A. Construction/Installation: All storm drain inlets have been constructed in accordance with the
approved construction plans and construction specifications.
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 Type C, R, 13 and 16 inlet covers are stenciled or stamped with the following designation (or
an equivalent): NO DUMPING – DRAINS TO POUDRE RIVER.
VI.Culverts - FCSCM Ch. 9, Sec. 4.0
A. Construction/Installation: All culverts have been constructed and/or installed in accordance with
the approved construction plans and construction specifications.
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 and the construction specifications. 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.
11/19
Yes
N/A
N/A
(Private on site storm only)
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 and construction specifications.
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 - FCSCM Ch. 8
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.
11/19
N/A
Yes
Yes
Yes
(Private on site storm only)
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.Permanent Erosion Control BMPs - FCSCM Ch. 9, Sec. 7.0
A. Construction: All permanent erosion control BMPs have been installed per the approved
construction plans.
1.All riprap has been installed in the locations and sizes indicated on the approved construction
plans.
2.All fabric has been installed in the locations and sizes indicated on the approved construction
plans.
a.All fabric was installed per the details on the approved construction plans.
XII.Post-Construction Site Cleanup - FCSCM Ch. 3, Sec. 2.0
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.
XIII.Certification of LID and Water Quality Facilities - FCSCM Ch. 7
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.
B.Attached is verification of the rain garden and/or sand filter flat surface area(s) and ponding
volume(s). This verification includes survey of critical elevations.
C.Attached is verification of the underground infiltration required volume(s), weir elevations,
orifices, inspection ports and filtering fabric. This verification includes survey of critical elevations.
D.All visible LID design features were verified as part of the engineer's site visit.
11/19
No
N/A
N/A
N/A
N/A
N/A
Yes
Yes
Yes
Yes
Yes
N/A
N/A
N/A
(Private on site storm only)
11/19 Page 8
XIV.Certification of Other Permanent BMPs
A.The construction of other permanent BMPs not specifically addressed in this certification is in
accordance with the approved plan. This may include grade control structures, rundowns, bridges, stream
access/improvements, etc.
Please specify other permanent BMPs included on this site:
XV. Certification and Erosion Control Measures - FCSCM Ch. 3
A. All temporary erosion control measures shall be removed upon stabilization. If at the time of preparing
this certification there are any erosion control measures still remaining on the site, please note them in
the narrative and verify that they need to remain at this time. If in doubt as to the need for any control
measure, please consult with the Erosion Control Inspector at erosion@fcgov.com.
XVI.Statement of Compliance - FCSCM Ch. 3
A. This certification is signed and stamped. By signing this form, the engineer(s) attests that he/she has
visited and observed the site, and to the best of his/her knowledge, the as-built conditions of the drainage
facilities are as described in the above form and in the enclosed as-built plans.
B.Failure to properly disclose all known information could result in the rejection of this certification and
prevent the release of any and all Stormwater Utility permit holds on Building Permits and/or Certificates
of Occupancy within this development.
XVII. Signature and Stamp by a Colorado-Registered Professional Engineer
Engineer’s contact information:
Name:
Email:
Phone:
Company:
Address:
PE Stamp
N/A
Jason Claeys, P.E.
jclaeys@highland-ds.com
970.674.7570
Highland Development Services, Inc.
6355 Fairgrounds Ave, Suite 100
Windsor, CO 80525
12/21/21
BUILDING 1
321 HICKORY STREET
BUILDING 2
331 HICKORY STREET
BUILDING 3
325 HICKORY STREET
LOT 1
HICKORY COMMONS
CITY OF FORT COLLINS
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BLOCK 21 RIVERSIDE PARK
SUBDIVISION
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AS-CONSTRUCTED MAP OF LOT 1, HICKORY COMMONS
LOCATED WITHIN THE SOUTHEAST QUARTER OF SECTION 2
TOWNSHIP 7 NORTH, RANGE 69 WEST OF THE SIXTH PRINCIPAL MERIDIAN
CITY OF FORT COLLINS, COUNTY OF LARIMER, STATE OF COLORADO
C.C.S. CONSULTANTS, INC.
4860 Robb Street, Suite 203A
Wheat Ridge, CO 80033
Phone: 303.403.4706
NOEL L. POTTERCOLORADO LICENSED
PROFESSIONAL LAND SURVEYOR26296
09.03.21
Hickory Commons
Critical Pond Elevations
Design Engineer:
Design Firm:
Project Number:
Date:
DESIGN CRITERIA
Urban Storm Drainage Criteria Manual, Urban Drainage and Flood Control District, June 2001
Stage Storage
Volume (pond volume calculated using the prismoidal formula):
Design
CONTOUR (FT)AREA (FT2)AREA (ACRE)VOLUME (ACRE-
FT)DEPTH (FT)CUMULATIVE VOLUME (ACRE-
FT)
4970.42 0 0.000 0.000 0.00 0.000
4971.0 777 0.018 0.003 0.58 0.003
4972.0 1,522 0.035 0.026 1.58 0.029
4973.0 2,505 0.058 0.046 2.58 0.075
4974.0 4,349 0.100 0.078 3.58 0.153
4975.0 12,172 0.279 0.182 4.58 0.335
0.084 4973.11 ft
0.280 4974.70 ft
As-Built
CONTOUR (FT)AREA (FT2)AREA (ACRE)VOLUME (ACRE-DEPTH (FT)CUMULATIVE VOLUME (ACRE-
4970.15 0 0.000 0.000 0.00 0.000
4971.0 975 0.022 0.006 0.58 0.006
4972.0 2,245 0.052 0.036 1.58 0.042
4972.75 2,245 0.052 0.039 2.33 0.081
4973.0 3,952 0.091 0.070 2.58 0.113
4974.0 7,311 0.168 0.127 3.58 0.240
4974.25 8,667 0.199 0.046 3.83 0.286
0.084 4972.77 ft
0.280 4974.22 ft
4972.80 Elev interpolate to volume of 0.087 acre-ft
Design Asbuilt Delta
4974.88 4975.90 1.02 ft
4974.88 4975.00 0.12 ft
4970.40 4970.15 -0.25 ft
4973.22 4972.80 -0.42 ft
0.084 0.087 0.003 acre-ft
0.280 0.280 0.000 acre-ft
Contour Areas Design Asbuilt Delta
4971 777.00 974.98 197.98 ft2
4972 1522.00 2244.76 722.76 ft2
4973 2505.00 3951.63 1446.63 ft2
4974 4349.00 7311.22 2962.22 ft2
Top of Berm Elev
Spillway Elevation
Pond Bottom
Top of Outlet Structure
WQCV
Pond Volume
Required 100-yr Detention Volume (including WQCV) =
Acre-Ft Interpolates to an Elev. of
Required Water Quality Capture Volume =
Acre-Ft Interpolates to an Elev. of
Required 100-yr Detention Volume (including WQCV) =
Acre-Ft Interpolates to an Elev. of
Water Quality Asbuilt Volume (Asbuilt Top of Contorl Structure)
A. Bartel
Highland Development
21-1050-00
December 8, 2021
Required Water Quality Capture Volume =
Acre-Ft Interpolates to an Elev. of
()
3
2121 DepthAAAA
V
++=
Page 1 of 1
This unofficial copy was downloaded on Nov-05-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact Engineering Office 281 North College Fort Collins, CO 80521 USA
This unofficial copy was downloaded on Nov-05-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact Engineering Office 281 North College Fort Collins, CO 80521 USA
This unofficial copy was downloaded on Nov-05-2020 from the City of Fort Collins Public Records Website: http://citydocs.fcgov.com
For additional information or an official copy, please contact Engineering Office 281 North College Fort Collins, CO 80521 USA