The development of a 1.23 acre project site for a new Carmen Dental Office Complex consisted of a 4,700 square-foot dental office, a 1,200 square-foot detached garage, sidewalks, concrete parking lots, and two (2) entrance drives.

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The project site was located South of East Robinson Street and East of Sonoma Park Drive. The proposed project site also encompasses three (3) undeveloped lots.

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The site development increased the impervious areas by 43% over the pre-developed conditions. This increase in impervious area slightly increased the amount of storm water runoff for the 2 to 100-year frequency storms by 97%. The City of Norman Design Guidelines allows a fee in lieu of constructing an on-site storm water detention facility at the discretion of the City Engineer. So, the proposed development requested a fee in lieu of on-site detention based on the following:

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• The project site was located at the top of two (2) separate drainage sub-basins.

• Adjacent properties that had been recently developed did not have on-site storm water detention facilities.

• The increase in impervious area was 43% over the existing site conditions.

• The increase in storm water runoff from the site for the most frequent storm events (2-25 year events) was 97%.

• The maximum storm water detention required (2,100 cubic feet) was less than 0.048 acre-feet of storage.