EXH1296052151

RE: Wetland Hydrology and the Third Runway Embankment Fill cn,_oo 4978-06 CC: Elizabeth Leavitt, Port of Seattle Denver During the course of the Third Runway project, the Port of Seattle and its consultants have evaluated a number of issuesthat relate to impacts to and preservation of the wetlands and maintaining baseflow to the creeks resulting from construction of the Third Runway Embankment. This memorandum presents the US Army Corps of Engineers (Corps) a _,,e,_,k5 summary and guide regarding these studies and how the analyses address key issues of concern regarding long-term protection of wetlands hydrology. We outline the understanding of current conditions at the Third Runway site, as they relate Jrrsev City to the main hydrologic processesthat maintain the wetlands and basetlow to Miller and Walker Creeks. We then describe the work done to assessthe potential for the Third Runway to affect these hydrologic processes,and how construction of the project is designed to avoid or mitigate adverse effects. Junedll UNDERSTANDING OF EXISTING CONDITIONS In this section, we answer the question: What are the soil and hydrologic features and L,,n. _._., characteristicsat or near the Third Runway site that maintain wetland hydrology? Hydrologic and Geologic Setting Portland The existing conditions at Third Runway site have been documented for both wetlands and hydrology/hydrogeology as part of the Fina/Environmenta/Impact Statement (FEIS) for the proposed Master Plan Update (FAA/Port of Seattle 1996), of which the Third Runway is a part: 1910 FaJrvmw Avenue East 5eaftle 5eattte. Washtngron 98102-3699 Fax 206.328.5581 Tel 206.32._.9530 AR 052151…

Open full document

Upcoming Events

PSCAA Advisory Council Meeting Agenda
Add to CalendarMWednesday Mar 11, 9:00am - 11:35am
1904 3rd Avenue, Suite 105, Seattle, WA 98101
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 [...]