HomeMy WebLinkAboutTIMBERLINE FARMS PUD, DIAMOND SHAMROCK CORNERSTORE - PRELIMINARY - 42-89C - SUBMITTAL DOCUMENTS - ROUND 1 - HAZMATS•
Hazardous Materials Impact Analysis
for
Diamond Shamrock
Timberline Farms Cornerstore, PUD
SEC of Timberline Road & Milestone Drive
City of Fort Collins, Colorado
June 1994
Prepared for:
Diamond Shamrock Inc.
520 E. 56th Avenue
Denver, CO 80216
(303) 297-9777
Attn: Scot Williamson
Prepared by:
Galloway, Romero & Associates
14202 E. Evans Avenue
Aurora, CO 80014
(303) 745-7448
Attn: David L. Jones
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The proposed development is a Diamond Shamrock Cornerstore
with automatic car wash and gasoline sales. It is located at the
southwest corner of Timberline Road and Milestone Drive in the City
of Fort Collins. The soil in this area is clay on the surface and
groundwater is about 18 feet below the surface at the time of the
soil boring (May 1994).
The adjacent property to the east and south is currently
undeveloped. The property to the north across future Milestone
Drive is also undeveloped. These properties are zoned EP for
future employment park. The properties to the west across
Timberline Road are zoned residential and currently contain single
family residences.
The hazardous material utilized by this operation is unleaded
gasoline. There will be three 12,000 gallon underground single
wall steel storage tanks located between the convenience store and
the car wash. The storage and distribution system complies with
the State of Colorado requirements regulating service stations.
The distribution system contains the following safety features:
(1) Multiple product dispensers with:
(a) Automatic nozzles to prevent customer overfill and
spillage.
(b) Hose break -away connections that separate and seal
the hose opening when customers drive off with the
nozzle still in the vehicle.
(c) Emergency shut-off valves under the dispenser that
shut off gasoline flow into the dispenser when
either:
(1) The dispenser sustains an impact and the
emergency valve shears away, or
(2) A fire melts a fusible link connection on the
valve.
(2) Dispenser containment sumps to collect any fuel spillage
under the dispenser and prevent soil contamination.
(3) Doublewall fiberglass piping to contain fuel in the event
of a primary piping failure.
(4) Submersible pump containment sumps to contain any fuel
leaking from the pump or piping connections.
(5) Float vent valves in tanks to prevent tank overfill by
truck transport driver.
(6) Cathodic protection system consisting of tank coating and
anodes.
(7) Pressure/vacuum vent valves to prevent tanks from
overpressurizing (positive or negative) during filling
• procedures or due to thermal contraction/expansion of
product.
(8) Submersible pump leak detector to shut down pump if
detector suspects a leak in the primary piping system.
(9) Monitor wells in the tank area to monitor for
contaminants in the soil and/or groundwater.
(10) Emergency stop switch at cashier's counter to shut down
entire fueling operation in the event of a spill or fire.
Fuel is delivered to the underground tanks by truck. Each
truck holds approximately 8,000 - 10,000 gallons. The most likely
route the transport truck would travel would be along Timberline
Road to the site from the south. The truck would leave the site
via Milestone Drive to Timberline Road.
Some of the most realistic scenarios involving use of gasoline
at this facility include:
(1) A spill at the dispenser due to consumer lack of
attention or mechanical failure. This spill would be
minimal based on a two minute response and a flow rate of
ten gallons per minute. Twenty gallons of gasoline
probable would not travel off site and could be
controlled by spreading an absorbing material and
evaporation.
(2) A larger surface spill originating at the underground
storage tank area during a product delivery. Gasoline is
"dropped" into the underground storage tank by gravity
fill. The most likely scenario would be the delivery
hose becoming disengaged from the truck or tank
connection. Since the truck driver is required by law to
stay within sight of and within control of the delivery
operation, a spill should not exceed a quantity of
approximately 250 gallons. In the event of this type of
spill, the fuel would travel to the southeast corner of
the site. The fuel would stay within paved areas
contained by site curbing. The outlet for stormwater in
this corner is a drainage channel that flows northeast to
the common access drive shared by the undeveloped lot to
the east. It would be possible for the driver to dam
this channel opening and contain the spill within the
paved drive areas of the site. The contained fuel could
then be properly cleaned up and disposed of under the
supervision of the fire department.
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