HomeMy WebLinkAboutGUARDIAN SELF STORAGE - PDP190020 - - PLANSFinal Plat pg 2
Please add leader
or relabel line:
"100-Yr Floodplain/
Floodway"
Planning Set pg 4:Please add floodplain line work and
add leader or relabel line:"100-Yr Floodplain/Floodway"
JR Response: Addressed
Utility Plans pg 6
Please add leader
or relabel line:
"100-Yr Floodplain/
Floodway"
JR Response: Addressed
JR Response: Addressed
Utility Plans pg 8
Please add leader
or relabel line:
"100-Yr Floodplain/
Floodway"
JR Response: Addressed
JR Response: Addressed
No-Rise Certification Memo pg 12
Please add leader
or relabel line:
"100-Yr Floodplain/
Floodway"
JR Response: Addressed
Guardian Storage Fort Collins
Final Drainage Report
2
near the site. The 2019 Fossil Creek LOMR floodplain model and report have been approved and have
now moved into the floodplain adoption process.
This development is in compliance with Chapter 10 of the City Code which contains the floodplain
regulations. The proposed building is intended to be constructed with a slab-on-grade foundation. The
revised BFE at out outfall location was estimated to be 4945.00 (NAVD88) and the lowest floor
elevation is set higher than the regulatory flood protection elevation(RFPE) at 4946.60 (NAVD88). Any
item that can float such as the bike rack will be anchored to the ground. The HVAC for the building is
set above the RFPE. The completion of the development meets the no-rise criteria from Chapter 10 of
the City Code. See structure floodplain information table below for more details.
Elevation (NAVD88)
City BFE upstream of structure 4945.0
Regulatory flood protection elevation 4946.5
Lowest floor elevation 4946.6
HVAC elevation 4946.6
Structure Floodplain Information
While this statement is true and can remain as is,we'll
need to make sure that this table contains the
interpolated BFE elevation (4944.8 NAVD88) at the
building site, same goes for the RFPE (4946.3
NAVD88).
Ted Bender, with the City of Fort Collins SW Master
Planning has interpolated the BFE at the building site.
This is the BFE we will regulate to and what the RFPE
will be based off of, not the BFE a the outfall.
Please feel free to contact me directly at 970.416.2494
or cquezada@fcgov.com if there are questions or if you
would like to discuss further.
Final Drainage Report pg 6
JR Response: Addressed
Guardian Storage Fort Collins
Final Drainage Report
8
HYDROLOGIC CRITERIA
The rational method was performed to calculate the peak runoff rates for each basin. Weighted percent
imperviousness and weighted runoff coefficients were calculated for each basin using the Fort Collins
Stormwater Criteria Manual Table 3.2-2 and Table 4.1-2. The time of concentration was calculated using
FCSCM Equation 5-3 and the intensity was interpolated from Table 3.4-1 in the FCSCM. The City of
Fort Collins area has 2-year, 1-hour rainfall depth of 0.82 inches and a 100-year, 1-hour rainfall depth of
2.86 inches. These depths do account for the 1997 adjusted rainfall depths.
HYDRAULIC CRITERIA
The ultimate Guardian Self Storage storm drainage system will be designed to convey the minor and
major storm events through the property with the proposed inlets, storm sewer pipes, and swales for
the flows being calculated by this report. Per the requirements provided by the City of Fort Collins
Storm Drainage Design Criteria and Construction Manual, all inlets and storm pipes will be designed to
convey the 100-year storm flows. During the major storm event, the developed condition 100-year
storm, the accumulated water depth in the sand filter will be held to a maximum level of one-foot below
all building finished floor elevations.
FLOODPLAIN REGULATIONS COMPLIANCE
As previously stated, the eastern portion of the Guardian Self storage site is within the City of Fort
Collins Fossil Creek flood plain. The City of Fort Collins is in the process of reanalyzing and updating
the Fossil Creek floodplain and the BFEs (Base Flood Elevations) for Fossil Creek near the site. The
revised BFE at out outfall location was estimated to be 4945.00 (NAVD88) and as such the lowest
building finished floor elevation is set at least 18” above that at 4946.60 (NAVD88). The portion of the
site that is within the floodplain is located within the ineffective flow area of the Fossil Creek floodplain
model and a no-rise memo will be completed to show that the proposed development is within the
ineffective flow area and will therefore result in no-rise of the BFE.
MODIFICATIONS OF CRITERIA
Chapter 6, Section 1.1 of the City of Fort Collins Stormwater Criteria Manual states that stormwater
detention is required on site. Due to the site's proximity to Fossil Creek, a "beat the peak" alternative in
Final Drainage Report pg 12