Staff raises maintainability, isolator‑row and percolation test concerns for storm‑chamber design

Engineering staff identified multiple maintenance and performance shortcomings in the proposed stormwater design and asked the applicant to revise plans to allow inspection and vacuum‑truck access. Staff said the current drawings show only small 4‑inch cleanout ports and no true isolator row, which could prevent removal of sediment, hamper inspection for hydrocarbons and ultimately blind the storm system.

"If sediment is allowed to fill your entire stormwater system, then it will decrease its volume and thus no longer function as designed," said Speaker 3 (Staff member), urging inclusion of an isolator row and manhole or catch‑basin access sized for vacuum‑truck piping. Staff also asked for a percolation or infiltration test conducted at the installation depth so the system’s drawdown time can be verified against the 72‑hour requirement.

Staff warned that if the chambers cannot be maintained and must be replaced it could disrupt the business because replacement requires removing pavement and damaging parking/drive‑through operations. The Authority included stormwater inspection, maintenance access and an infiltration test among conditions for final approval.