(A) Where detention or retention systems are proposed to be used as part of the drainage system, required low flow channels shall be constructed as the first element of the initial earthwork, silt fences and erosion controls shall be in place before earthwork commences. Additionally, the detention outlet inlet area, within the storage area, shall be protected with a riprap silt collection berm (IDOT Class A3 minimum) set at a 15-feet radius around said inlet. The height of said berm shall be equal to the top elevation of the lowest structure inlet/intake but shall not be less than 18 inches. Any eroded sediment captured in these facilities shall be removed by the applicant on a regular basis and before project completion in order to maintain the design volume of the facilities. Alternate permanent concrete drop structures providing silt collection in advance of the inlet may be considered.
(B) The detention outlet structure inlet shall be protected with a rip rap silt collection berm (five- inch clean stone - RAP 6) set at a 15-feet radius around the inlet. The height shall be equal to the top elevation of the lowest structure inlet with an 18- inch minimum height. Any eroded sediment captured in these facilities shall be removed by the applicant on a regular basis and before project completion in order to maintain the design volume of the facilities. Alternate permanent concrete drop structures providing silt collection in advance of the inlet may be considered.
(Ord. 1108, passed 8-23-1999; Am. Ord. 1378, passed 6-26-2006; Am. Ord. 1573, passed 2-28-2011; Am. Ord. 1696, passed 3-21-2016)