(A) Evaluation. All natural channels permitted to remain undisturbed will be reviewed for depth, width, velocity, and the like for a 100-year storm using hydraulic techniques acceptable to the village. These channels must be located such that the maximum water surface elevations due to the 100-year storm including backwater from culverts or other restrictions shall be two feet below the lowest opening in any building.
(B) Alignment. The horizontal or vertical alignment of a natural channel may not be indiscriminately changed and continued as an open channel simply to provide more useable land. A channel changed for any purpose must become part of the underground storm sewer system except as outlined below.
(C) Channel upgrading. At the village's discretion, natural channels contiguous to or running through an area being considered for development, but not to be disturbed by the development, shall be studied by the village to determine the need for upgrading, rehabilitation, or maintenance. If required, the developer shall provide such design information as needed along with a plan showing in detail the work to be done. This work may consist of tree, debris, and obstruction removal, bottom and slope erosion control, slope establishment with rock or other protection, recut of slopes to more stable angle and the like. Each area will be considered on its own merits. The developer shall make any improvements deemed necessary by the village.
(D) Private drainage easements. Size of required private easements will be based on the water surface spread for the 100-year storm. Each natural channel shall be individually studied and easements required which will be in the best interests of the village and the property owner.
(Ord. C-604, passed 9-8-86)