HomeMy WebLinkAboutSite Certifications - 02/07/2019Accepted 2/7/2019
WL
WL - verified these were installed.
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.)
12/15 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
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
12/15 Page 4
Filter Media
Filter media composition is per design specifications
Filter media was “machine mixed” by supplier prior to delivery
Filter media installed flat and level
Other Structural Components
Containment wall/berm is continuous and level
Landscaping
Final landscaping does NOT include sod
Final landscaping (wood/rock mulch) is flat and level
Vegetation is planted according to landscape design
specifications
Verify that weed barrier is not installed
Temporary irrigation installed If N/A, then verify that permanent irrigation is installed to
establish/maintain vegetation
Close Out
Upstream catchment stabilized prior to diverting runoff into
bioretention cell
Signature:
Name:
Title:
Email:
Phone:
Company:
Address:
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12/13/2018
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12/13/2018
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City of Fort Collins, Colorado
UTILITY PLAN APPROVAL
DateCity Engineer
DateWater & Wastewater Utility
DateStormwater Utility
DateParks & Recreation
DateTraffic Engineer Date
DateEnvironmental Planner
Date
Larimer County, Colorado
UTILITY PLAN APPROVAL
Larimer County Engineer Date
KEY MAP
ESPALIER & TREE ROW LANES STORM LINE PLAN
(PHASE 3)
STORM LINE PROFILE
STA 9+50.00 TO 18+40.00
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7200 South Alton Way, Suite C400
Centennial, CO80112
303-740-9393 x Fax 303-921-7320
130 East Kiowa Street, Suite 400
Colorado Springs, CO80903
719-593-2593 x Fax 303-921-7320
2900 South College Avenue, Suite 3D
Fort Collins, CO80525
970-491-9888 x Fax 303-921-7320
MEMORANDUM
JR Engineering, LLC has completed a conceptual drainage analysis for lots 1-6 in the 5th phase of filing 2, of
the Kechter Farm project. The following is a summary of the findings discovered while performing a conceptual
drainage analysis of the proposed Kechter Farm project in order to determine if the lots in the northwest corner
of the site can be graded as garden lots and have rear yard storm runoff drain onto the City of Fort Collins
property to the northwest of Kechter Farm; similar to the northeast corner of the Mail Creek drainage basin D3.
If lots 1-6 were graded to garden lots (see attached conceptual drainage exhibit), the runoff from the back half
of the lots would drain west to the on-site open space tract and be collected in a swale, from there flows would
be routed north to the northwest property corner and onto the City of Fort Collins property to the northwest of
the site, see the attached exhibits. This drainage pattern would be similar to that of the Mail Creek Crossing
drainage. According to the Mail Creek Crossing Drainage report completed by Northern Engineering in
December 2013, runoff from Basin D3 drains to the back of the lots into swales and onto the City of Fort
Collins property at the northeast property corner (see Mail Creek drainage exhibit drainage node D3).
Historically, the entire Mail Creek site drained to the northeast corner of their site and with the majority of the
proposed condition flows draining elsewhere, the proposed minor and major storm event flows entering onto the
City of Fort Collins property are considerably less than the historic flow rate. The Mail Creek Crossing report
states that the historic flow rates at the property corner were 9.7 cfs in the 2-year event and 44.4 cfs in the 100-
year event. The Mail Creek developed basin D3 generates 1.8 cfs in the 2-year event and 7.8 cfs in the 100-year
event at the same property corner. See attached excerpts from the Mail Creek Drainage Report.
This proposed basin from Kechter Farm creates 0.6 cfs in the 2-year event and 2.6 cfs in the 100-year event.
Directly adding these storm flows to the 100 year runoff created from the Mail Creek Crossing site, we get 10.4
cfs in the 100-year event. This new combined basin of D3 and lots 1-6 generate 100-year flow rates within 1 cfs
of the historic 2-year event at this location.
The grading of the 6 Kechter Farm lots into garden style lots would create a minor increase in runoff onto the
City of Fort Collins property, the total developed basin draining to the City’s property is significantly less
runoff than the historic condition. In fact, the developed condition drainage basin essentially would meet the
City’s requirement of 100-year developed flow rate down to the historic 2-year event, without detention
necessary. Additionally, the water quality for this minor change is handled in the proposed natural swale and the
grass buffer on the City of Fort Collin’s property. Thus, we request approval to revise Kechter Farm, Filing 2,
Phase 5, Lots 1-6 from A to garden style grading.
Sincerely,
Tim Halopoff , PE
To:Shane Boyle
From:Tim Halopoff, PE
Date:June 8, 2016
Subject:Kechter Farm-Conceptual Drainage Revision Analysis (Filing 2, Phase 5, Lots 1-6)
Subdivision:Kechter Farm Filing 2 Project Name:Kechter Farm
Location:Fort Collins Project No.:
Calculated By:BAB
Checked By:0
Date:6/6/16
A 0.65 95%0.22 31.9%5%0.43 3.3%35.2%
TOTAL 0.65 35.2%
COMPOSITE PERCENT IMPERVIOUS CALCULATIONS
39713.00
Basin ID Total Area
(ac)
Roofs Lawns/ Grass Basins Total
Weighted %
Imp. (%)Area (ac)Weighted %
Imp. (%).% Imp. (%) Area (ac)Weighted %
Imp. (%).% Imp. (%)
X:\3970000.all\3971300\Excel\Drainage\Drainage_Calcs_3971300_v2.0.xlsm Page 1 of 1 6/7/2016
Subdivision:Kechter Farm Filing 2 Kechter Farm
Location:Fort Collins
BAB
0
6/6/16
A 0.65 0.95 0.22 0.32 0.25 0.43 0.17 0.49 0.61
TOTAL 0.65 0.49 0.61
C100= 1.25* Basin Total Weighted Runoff Coeff
Basins Total
Weighted
Runoff Coeff.
C2
COMPOSITE RUNOFF COEFFICIENT CALCULATIONS
Total Area
(ac)Basin ID
39713.00
Basins Total
Weighted Runoff
Coeff. C100
Runoff
Coeff.Area (ac)
Lawns, Heavy Soils (Type C)
Runoff
Coeff.Area (ac)Weighted
Runoff Coeff.
Roofs
Weighted
Runoff Coeff.
X:\3970000.all\3971300\Excel\Drainage\Drainage_Calcs_3971300_v2.0.xlsm Page 1 of 1 6/7/2016
Subdivision:Kechter Farm Filing 2 Project Name:Kechter Farm
Location:Fort Collins Project No.:
Calculated By:BAB
Checked By:0
Date:6/6/16
FINAL
BASIN D.A. Hydrologic Impervious C2 C100 L S o t i L t S o K VEL.t t COMP.t c TOTAL Urbanized t c t c
ID (ac) Soils Group (%)(ft)(%)(min)(ft)(%)(ft/s)(min)(min)LENGTH (ft)(min)(min)
A 0.65 C 35%0.49 0.61 60 2.0%32.1 300 2.0%7.0 1.0 5.1 37.2 360.0 14.8 14.8
NOTES:
t c =t i +t t (Equation 6-2)
t i = (1.87*(1.1 -C*Cf)*(L)^0.5)/((So)^0.33)
L= length of overland flow ( 500' max)
C= runoff coefficient
Cf= Frequency adjustment factor
t i = overland (initial) flow time (minutes)K
S = Average Slope along the overland flow path, ft/ft 2.5
t t =L/(60K*(So)^0.5 (Equation 6-4)5
t t = channelized flow time (minutes)7
S = waterway slope, ft/ft 10
V t = travel time velocity (ft/sec) = K*So^0.5 15
20
First Design Point Time of Concentration:
t c =(18-15*i )+L/(60*(24*i +12)*(So)^0.5)(Equation 6-5)
i = imperviousness (expressed as a decimal)
t c is lesser of Equation 6-2 and Equation 6-5.
For Urbanized basins a minimum t c of 5.0 minutes is required.
For non-urbanized basins a minimum t c of 10.0 minutes is required.
(URBANIZED BASINS)DATA
INITIAL/OVERLAND
(Ti)
TRAVEL TIME
(Tt)
STANDARD FORM SF-2
TIME OF CONCENTRATION
SUB-BASIN tc CHECK
39713.00
Table 6-2. NRCS Conveyance Factors, K
Nearly bare ground
Grassed waterway
Paved areas and shallow paved swales
Type of Land Surface
Heavy Meadow
Tillage/field
Short pasture and lawns
X:\3970000.all\3971300\Excel\Drainage\Drainage_Calcs_3971300_v2.0.xlsm Page 1 of 1 6/7/2016
Project Name:Kechter Farm
Subdivision:Kechter Farm Filing 2 Project No.:
Location:Fort Collins Calculated By:BAB
Design Storm:Checked By:0
Date:
TRAVEL TIME
STREET
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REMARKS
1 A 0.65 0.49 14.8 0.32 1.87 0.6
DIRECT RUNOFF TOTAL RUNOFF STREET PIPE
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
2-Year
39713.00
6/6/16
X:\3970000.all\3971300\Excel\Drainage\Drainage_Calcs_3971300_v2.0.xlsm Page 1 of 1 6/7/2016
STANDARD FORM SF-3
STORM DRAINAGE SYSTEM DESIGN
(RATIONAL METHOD PROCEDURE)
Project Name:Kechter Farm
Subdivision:Kechter Farm Filing 2 Project No.:
Location:Fort Collins Calculated By:BAB
Design Storm:Checked By:0
Date:
TRAVEL TIME
STREET
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REMARKS
1 A 0.65 0.61 14.8 0.40 6.53 2.6
39713.00
PIPE
100-Year
DIRECT RUNOFF TOTAL RUNOFF STREET
6/6/16
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