HomeMy WebLinkAboutWaiver Request 09-07-22
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September 7, 2022
Mr. Jeremy Kashman, P.E.
City Engineer’s Office
City of Carmel
One Civic Square
Carmel IN 46032
RE: Bedford Falls of Carmel Subdivision
Request for Approval of Design Standard Waiver
Mr. Kashman, on behalf of Less Impact Development, the owner of the Bedford Falls of Carmel Subdivision, I
am requesting a waiver of Section 302.06.1 of the City of Carmel’s Stormwater Technical Standards Manual for
the development.
Section 302.06.1 of the Technical Standards Manual states in part, that “The detention facility shall be designed
in such a manner that a minimum of 90% of the maximum volume of water stored and subsequently released at
the design release rate shall not result in a storage duration in excess of 48 hours from the start of the storm
unless additional storms occur within the period.”
The drawdown of the pond is not meeting this requirement, which is due to multiple factors. First, the pond is
designed to meet the release rate requirements set forth by the Hamilton County Surveyor’s Office. If the
release from the site is increased to meet the drawdown requirement, then the allowable release rates will be
exceeded. Second, the Copper Trace detention system drains through the detention system of Bedford Falls of
Carmel. This extended flow entering the proposed system elongates the drawdown of the pond. Third, the base
flow from Williams Creek reduces the outflow from the proposed detention system, which also extends the
drawdown from the proposed detention system. These three listed factors all negatively affect the drawdown of
the proposed detention system and prevent this requirement from being met.
Mr. Kashman, please consider this request and let me know if you need any other information.
Sincerely,
Duane A. Sharrer, P.E.
Vice President, Residential Development