EXH0352021192

iLE: Supplemental Information, Department of the Army Section 404 Permit Application, SeaTac Airport. USACE Reference 1996-4-02325 Dear Ms. Kenny, Walker, and Terzi: My comments in the meeting on July 10_ between Airport Communities Coalition representatives and the Department of Ecology elicited some questions from Ms. Kermy about the performance record ofstormwater Best Management Practices (BMP's). This letter provides clarifying detail and documentation inresponse to these questions. It also provides elaboration of previous comments on stored stormwater for flow augmentation. The first question concerned bacteria loading associated with biofiltration swales. Results compiled • from a rangeofBMP perfor!rtance monitoringefforts (Claytor et al., excerpt enclosed) conclude that bioswales or open grassed channels have either low or negative removal efficiencies for fecal coliform. Both the enclosed EPA 1999 compilation and the work by AdoIfson (1999, excerpt enclosed) concur in these results. Negative removal efficiency means that more bacteria were measured in the discharge than were measured in the inflow to the BM:Pin question. This result was observed in the 1992 Metro study onwhich the Port relies, as well as numerous others. These results have not been rigorously accounted for, but one opinion is that bioswales can exhibit bacterial growth anti behave as a source of bacteria themselves. Strecker et al. (enclosed) developed recommended parameters for assessing BMP performance. The Department of Ecology and Corps of Engineers should require the Port of Seattle to provide the recommended information on the BMP's that it is proposing at SeaTac, and rigorously review them, before accepting claims that…

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PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
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Call to order – Roll Call – Quorum Established – Land Acknowledgement We would like to acknowledge that our Agency operates in four present-day counties, which are the traditional lands of the Coast Salish people, past and present. This acknowledgement does not take the place of authentic relationships with indigenous communities in our jurisdiction and [...]