HomeMy WebLinkAboutUtilities Follow-Up CommentsGetGo #3557 CARMEL, IN
146th & Gray Road
Carmel Utilities’ Follow-up Review Comments Regarding
Impact of New Fueling System on Wellhead Protection Plan
1) General
a. This site sits approximately 500 feet west (outside) of the one-year time of travel
boundary of Carmel’s Wellhead Protection Area. Even though this site sits outside of
this time of travel boundary, its close proximity to this boundary causes due concern by
Carmel Utilities.
b. Because of the close proximity of this potential source of contamination to Carmel’s
Wellhead Protection Area, Carmel Utilities is of the opinion that a multi prong approach
be implemented to minimize the chance of contamination migrating into Carmel’s
Wellhead Protection Area.
c. A multi prong approach at a minimum should include containment, frequent routine
monitoring of fuel and stormwater systems and the below grade environment
surrounding the fuel and stormwater systems, and submission of routine monitoring
reports, including the reporting of spill events and response(s), to Carmel Utilities.
2) Containment
a. After reviewing the “Fuel System” plans provided earlier, we offer the following
comments.
b. Sheet FG300 and FG304 – in reviewing these two sheets we suggest that the USTs, fuel
piping and dispensers be completely contained within a geosynthetic liner that will act
as a tertiary containment for leaks, spills and overfills from the USTs, fuel piping and
dispenser area as shown on these sheets.
c. Stormwater Retention – no information has been provided in regard to the construction
of the stormwater retention system. Please provide engineered drawings showing the
complete stormwater system. All surface water storage areas and conveyance channels
should also be completely lined with a geosynthetic liner.
3) Monitoring
a. Although the “Conceptual Fuel System Design and Wellhead Protection Plan” indicate
that monitoring wells will be installed within the tank excavation, the location of
monitoring wells are not clearly defined or shown on the “Fuel System” plan previously
provided. Please provide engineered drawings showing the location of all monitoring
wells for this site.
b. Carmel Utilities recommends the installation of additional monitoring well(s) down
gradient and outside of the tank excavation.
c. According to the “Conceptual Fuel System Design and Wellhead Protection Plan”, under
dispenser containment sumps will not be of double wall construction. Will the under
dispenser containment sumps be individually monitored for product release? If so,
please explain how they will be monitored.
d. Will USTs employ wet or dry monitoring of the interstitial space? The “Fuel System”
plans indicate this will be a dry system, whereas the “cut sheets” provided for the USTs
indicate this will be a wet system. Please clarify.
4) Reporting
a. Update Contact List in “Emergency Response Plan” to include after-hours reporting
contact info for Carmel Utilities and Carmel Engineering.
b. The inspection check list provided does not list Aqua Swirl, Aqua filter or any
stormwater system components. Please develop and provide a copy of an inspection
check list for stromwater system components including routing testing (inspection check
list should also indicate the frequency of inspection and testing). A completed
inspection check list should be sent to Carmel Utilities once every 6-months following
the completion of the routine inspection/testing.