(A)   The use of stormwater storage facilities described in §§ 153.207 and 153.208 are the preferred means of stormwater storage. The following alternative means of stormwater storage may be used on sites under two acres in area or where practical necessity makes the use of stormwater storage areas infeasible. The use of such alternative areas is only permitted upon the approval of the Board of Trustees.
   (B)   Design and construction of the pavement and structural elements must assure that there is minimal damage due to flooding. Control structures must be readily accessible for maintenance and cleaning. Flow control devices will be required.
   (C)   No stormwater detention shall be located upon street pavements. Street pavement surface ponding shall not exceed nine inches in depth in the gutter line under all rainfall conditions up to and including the 50-year storm event. Open waterways such as surface overflow swales shall be designed into the grading plan to receive all excess stormwater runoff. Depressing sidewalks across such overflow swales to meet this requirement shall be acceptable. Street ponding shall be allowed only for the conveyance of excess stormwater runoff.
   (D)   Parking lots may be designed to provide temporary detention storage on a portion of their surfaces. These lots may be constructed to store water to a depth of 0.6 feet and these areas must be located in the most remote, least used areas of the parking facility. Designs must ensure minimal damage to the parking facilities and warning signs shall be mounted at appropriate locations to warn of possible flood conditions during storm periods.
   (E)   Underground storage facilities must be designed for easy access in order to remove accumulated sediment and debris. These facilities must have a positive gravity outlet unless otherwise authorized by the Village Engineer.
(Ord. 97-7, passed 7-1-1997, § 5.19)