HomeMy WebLinkAboutSite Certifications - 10/13/2015O\)erAIL Q4e 6fA4,1aM Cer A,(''AiL
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700 Automation Drive, Unit I
Windsor, CO 80550
Phone:970-686-6939
Fax:970-686-1188
August 21, 2015
Wes Lemarque
City of Fort Collins
700 Wood Street
Fort Collins, CO
Re: Home Instead Plaza Record Drawings
Mr. Lemarque
This letter is to serve as an overall site certification for Home Instead Plaza (Lot 1 Home
Instead Plaza). All information provided in this letter and on the record drawing plans
you have received is based on a field survey completed by Washburn Land Surveying
dated July 7, 2015.
The pond was constructed with sufficient volume per the design but the top of the outer
retaining wall was constructed 0.5' lower than, design. The pond provides adequate
volume at elevation 5034.05 prior to overtopping at elevation 5034.50. An as constructed
stage storage table is attached.
The LID swale on the west side of the building was constructed at the elevations per the
design plans. All storm on site is private and was not inspected. The permeable pavers
were installed on site and photos of the installation process are provided at the end of this
letter.
The finished floor of the buildings were constructed at or within 0.10' of the design
elevation and all curb and gutter (private) on site were constructed within acceptable
construction tolerances. There appears to be (based on the field survey) sufficient slope
away from the buildings to allow runoff to adequately flow in the direction as intended
by the original design plans.
If you have and questions or need additional information for this certification, please call
me.
Patricia Kroetch, P.E.
Subgrade Preparation for Pavers & underdrain installation
No Text
Close up of impervious liner
Compaction of 4" Rock Base layer & Installation of 2" Crushed
Installation of Z" Crushed Rock layer with a view of compacted Rock layer underneath
Paver Installation
Paver installation complete
Installation of aggregate in openings between pavers.
STAGE - STORAGE TABLE
100-YEAR
LOCATION: JFK & Boardwalk
PROJECT NO: 347-02
COMPUTATIONS BY: PPK
DATE: 8/31/2015
Extended Water Quality Volume Required = 0.031
100 yr Detention Volume Required = 0.174
Total 100 yr Volume Required = 0.205
WQC6
100 year WSEL
Spillway Elevatior
Stage
(ft)
Surface
Area
(ft`).
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
5029.25
0
5030
1,158
0.007
0.007
5030.90
1,264
0.025
0.032
5031
1,276
0.028
0.035
5032
1,406
0.031
0.065
5033
2,161
0.041
0.106
5034
2,285
0.051
0.157
5034.42
2,338
0.140
0.174
5035 1
2,412
0.054
0.211
ASBUILT VOLUME
WQCD
100 year WSEL
Spillway Elevation
Stage
(ft)
Surface
Area
(ft`)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
5029.21
0
5030
1,192
0.007
0.007
5030.64
1,364
0.019
0.026
5031
1,460
0.030
0.038
5032
1,615
0.035
0.073
5033
2,182
0.043
0.116
5034
2,476
0.053
0.170
5034.05
2,484
0.136
0.174
5034.5 1
2,556 1
0.029
0.199
0
l
COMMERCIAL, MULTI -FAMILY AND SUBDIVISION
CERIFICATION FORM & CHECKLIST
(Overall Site Drainage Certification)
Home Instead Plaza
(Project Name)
5/21/15
(Date)
(For Commercial or Multi -family please list any applicable building permit numbers)
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. Caution, several of the items need to be verified during construction. A copy of the
approved grading plan must be submitted with the as -built grading plan. (It is preferred to have the as -
built elevations 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 that is being certified.
If any blanks are "No" you must provide and explanation on an attachment referencing the item number
below.
Attach an explanation or description of the as -built condition for any of the items listed or for something
that is not listed but is shown on the approved construction plans.
Please provide an As -Built Redline or Mylar drawing showing the following:
I. Water Quality & Quantity Detention Basin Certification-FCSCM Vol.2, Ch.10 (For multiple basins on a
site provide the following for each basin separately)
A. Volume: X As -built topographic verification is attached at one foot contour intervals (or less)
and volume verification calculations for the water quality capture volume and the 100 year detention
storage volume.
1. x Detention basin topography was prepared by a professional land surveyor registered in the
state of Colorado.
2. X Both proposed and as -built contours are shown on the same plan sheet.
(Dashed lines for proposed and solid lines for as -built)
3. x 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. x Stage -storage -discharge tables are provided on a separate document.
5._As-built verification is attached showing detention basin meets state regulation drain times.
B. WQ & Quantity Detention Basin Grading: _Attached is as -built verification that there is a 2%
(min.) 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 must still meet the 2% (min.) grade
requirement to drain into it.
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 2% (min.) 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 meeting the grades as shown on the approved construction
plans. (Show as -built spot elevations)
c. Soft Pan for low flow in detention basin.
(1) Verify and document the soft pan material gradation, trench width and depth. This will
need to be verified during installation by the engineer. Picture documentation preferred or
engineers statement of visual inspection and compliance.
(Choose applicable choice below)
(2) There is a soft pan with an underdrain installed meeting the design on the approved
construction plans (Show the underdrain grades, bedding material, geotextile, spot elevations,
bends, cleanouts, etc.).
(3) 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: x The as -built side slopes of the detention basin have been calculated and are
shown. Indicate the slide slope with an arrow and a numerical value beside it (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. If there was a variance granted for steeper slopes during the
design process you must provide the variance documentation.
3. Compaction: All berms and embankments meet the compaction requirements as specified
in the project geotechnical report or complies with the City's standard. The City's standard
requirement 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)" This is an item requiring verification during construction. Provide testing log from
contractor/engineer.
4. Spillway Certification: The following items must be field verified:
a. The location of the spillway is indicated on the as -built plan. Spillway is top of wall
b. The width of the spillway is indicated on the as -built plan. Width not defined
C. x The elevation(s) of the spillway is shown on the as -built plan.
d. x There is a concrete ribbon defining the location and grade of the spillway. Wall
e. x There is downstream scour protection in the spillway as per the construction plans.
Indicate type pavement (riprap size "D50" gradation and bedding type, geotextile,
buried riprap with inches of bury, etc.)
f. x There are no obstructions in the spillway such as trees, bushes, sidewalks, landscape
features, rocks, etc.
5. Outlet Structure Certification
a. x The orifice plate for the approved release rate is installed with the correct size and
location of the orifice.
b. x The orifice plate for the water quality outlet is installed with the correct hole size,
number of rows, and columns of holes.
c. x The bottom hole on both the water quality and quantity outlets are at the bottom of the
plate so that there is no water being ponded in front of the plate.
d. x The well screen is the correct material and is installed as shown on the construction plans.
e. x 100 year over flow grate elevation is 5031.86 . (Elev. A on detail D-46)
f. x The top elevation of the water quality capture volume is 5030.63
(Elev. B on detail D-46)
g. x Overflow grate is made of the correct material, has the correct bar spacing, is hinged at the
top, and bolted at the bottom.
h. x 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 and
they meet or exceed the capacity requirements shown in the approved drainage study for this
project.
1. n a All swales are located within the drainage easements as shown on the construction plans.
2.X_Logitudinal slopes and side -slopes (cross -sections) have been verified. Design Upend per design
rPgijmrPg Inogitildipal slopes of 296 min. (on vegetated swales) and side -slopes no steeper than 4:1. If
these criteria are not met the certification engineer needs to write a justification and propose
mitigation for each instance or have the issues corrected. If variances to these criteria have been
approved previously and they are shown on the construction plans no justification is needed.
3. x As -built spot elevations on channels/swales are shown that correspond to spot elevations
shown on the approved construction plans.
4. x All permanent erosion control measures are installed as shown on the approved construction
plans. (i.e. drop structures, riprap, TRMs, etc.) Pictures and verification of the materials used need
to be included as part of this verification.
5. x All pans, curbs, storm pipes, or other appurtenances appropriately tie into each other in the
system. Pictures at tie-in points suggested.
6.. x 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 a separate documentation.)
7. x 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.)
III. Pipes (aka storm drains)-FCSCM Vol.1, Ch.6, Sec. 4
A. Strom drain pipe Capacity: The as -built capacity of all the pipes installed on this project have
been verified and they meet or exceed the capacity requirements shown in the approved drainage
study for this project.
1. x All pipe sizes and materials of the storm drain pipes 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. x 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. x 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
approved construction plans.
x All pipes are installed in accordance with the
1. x 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. n/aAll encasements and clearances as specified on the approved construction plans have been
met.
3. n/a Any specific joint types or construction methods specified on the approved construction
plans have been met. (Please list any of these on a separate sheet and attach it to this certification.)
4. 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)
IV. Concrete Pans-FCSCM Vol.1, Ch.7, Sec.4.1.3.4
A. Construction/installation: n/aAll 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 slope 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. (Of particular concern is
that the pan cross-section is "V" shaped, meeting 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.
V. Storm Drain Inlets-FCSCM Vol.1, Ch.6, Sec. 3
A. Construction/Installation: x All storm drain inlets have been constructed in accordance with the
approved construction plans.
1. x The size and type of inlets are consistent with the inlets shown on the approved
construction plan. Indicate by writing in "Verified" 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. x 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. x 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 ft. 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. If not, attach an
explanation orjustification.
r,
VI. Culverts-FCSCM Vol.2, Ch.9
A. Construction/Installation: All culverts have been constructed/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 to 1. Please note areas needing stabilization in the
certification narrative. An alternative to consider is a TMR (Turf Reinforcement Mat).
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: sub -drains installed after
the plans were approved need to be indicated on the as -built plans also)
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.
3. The minimum cover requirements are being provided.
4. The clean -Outs have been installed at the locations shown on the construction plans and are
accessible for cleaning. ( Cleanouts can be buried if they are not buried more than 6 inches and
there are markings to locate their locations.)
5. The backfill materials for sub -drains are as shown on the approved construction plans. (This
includes the depth and width as shown.)
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 only accepted if approved prior to installation.)
Vill. 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" 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.
2. The as -built contours for "Overlot grading" are shown on the as -built construction plans for
all common open spaces, Tracts, 0utlots, etc. If not in 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 Matts (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 the sizes indicated on the
approved construction plans.
1. The riprap bedding is a granular bedding of the gradation and thickness indicated on the
approved construction plans.
2. 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. The riprap is the gradation shown on the approved construction plans with a D50 of
4. The riprap thickness is as shown on the approved construction plans and extend to the
horizontal limits shown.
5. The riprap is buried to the depth indicated on the approved construction plans. (A minimum
of 6 inches of soil is required)
XII. Permanent Erosion Control Fabric-FCSCM Vol.1, Ch.7
A. Construction: All fabric has been installed in the locations and the sizes indicated on -the
approved construction plans.
1. All fabric was installed per the details on the approved construction plans.
2. All fabric was installed per manufacturer specifications.
XIII. Post Construction Site Cleanup-FCSCM Vol.3, Ch.7
A. Construction: x All construction debris or any type of obstructions have been removed from
drainage paths.
1. x All construction debris has been removed except in staging area(s) designated on the
erosion control plan.
2, x All ruts have been smoothed out in all construction areas.
3. x All areas needing reseeding have been identified and stabilization has been coordinated
with the Erosion Control Inspector. Note area needing stabilization in the narrative.
XIV. Certification of Other Permanent BMPs-FCSCM Vol.2, Ch.B, 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.
B. 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.)
XV. Certification of LID and Water Quality Facilities-FCSCM Vol.3, Ch.4
A. x Attached are the certifications for Low Impact Development (LID) or other water quality
facilities along with their certification check sheets, pictures, and other required documentation.
XVI. Certification of Erosion Control Measures
A. Certification of the Erosion Control measures is a separate process to be completed with the
Environmental Regulatory Affairs Erosion Control Inspector. However if at the time of preparing this
certification there are any of the erosion control measures needing maintenance please note them
in the narrative and report them to the Erosion Control Inspector @ 221-6700.
XVII. Statement of Compliance
This certification is si "ned and stain ed and b si nin this farm the En ineer s 'attests that they.
have
B P Y g g g (..� .
inspected the site and to the best of their knowledge the as -built conditions of the drainage facilities are
as described in the above form and in the As -Built plans enclosed.
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.
XVIII. Signature and Stamp by a Colorado Registered Professional Engineer
Engineers contact information:
Patricia Kroet North Star Design Inc
(Name) (Company Name)
tricia@northstardesigninc.com 700 Automation Dr, Unit I, Windsor 80550
(Email address)
970-686-6939
(Telephone number)
(Company Address)
PE STAMP