Should a site require a retaining wall, a detail shall be indicated on the plans to indicate the type and style of wall to be used. A retaining wall that is greater than three feet (3') in height shall be designed and sealed by an Illinois licensed professional engineer. The design criteria can be provided during the final engineering submittal.
Retaining walls around detention basins may not be continuous. There must be a sloped opening to allow for maintenance. Walls greater than three feet (3') in height are not permitted in this application. If a height of greater than three feet (3') must be attained, the wall must be constructed in a terrace fashion, three foot (3') maximum high wall to a minimum three foot (3') wide terrace, then another three feet (3') maximum wall to another minimum three feet (3') wide terrace, etc.
The underdrain outlet shall be shown on the plans. The ends of the retaining wall shall transition so that the grading shall not exceed the maximum transition grading of 4:1. (Ord. 2018-02-20, 2-20-2018)