EXH2018030065

5808 Lake Washington Blvd. N.E., Suite 200 Kirkland, Washington 98033 December 2001 556-2912-001 (03) AR 030066 TABLE OF CONTENTS Page EXECUTIVE SUMMARY ............................................................................................................. x 1. INTRODUCTION ............................................................................................................ 1-1 1.1 PROJECT DESCRIPTION ...................................................................................... 1-1 1.2 KEY PROJECT ELEMENTS .................................................................................. 1-2 1.2.1 Runway Safety Areas and Relocation of South 154 thStreet ....................... 1-3 1.2.2 New Third Runway ...................................................................................... 1-3 1.2.3 Borrow Areas ................................................................................................ 1-3 1.2.4 South Aviation Support Area ....................................................................... 1-6 1.2.5 Overview of the Mitigation Plan .................................................................. 1-6 1.3 WETLAND DELINEATION ................................................................................... 1-6 1.4 SIGNIFICANT WETLANDS AVOIDED BY MASTER PLAN IMPROVEMENTS ................................................................................................. 1- 19 2. METHODS ....................................................................................................................... 2-1 2.1 IMPACTS TO WETLAND AREA ......................................................................... 2-1 2.1.1 Direct Impacts ............................................................................................... 2-1 2.1.2 Indirect Impacts ............................................................................................ 2-1 2.2 IMPACTS TO WETLAND FUNCTIONS .............................................................. 2-2 2.2.1 Background ................................................................................................... 2-2 2.2.2 Assessment Methodology ............................................................................ 2-4 3. FUNCTIONS OF WETLANDS IN THE PROJECT AREA ........................................... 3-1 3.1 SUMMARY OF WETLAND FUNCTIONS .......................................................... 3-1 3.1.1 Biological Functions ..................................................................................... 3-8 3.1.2 Physical Functions ...................................................................................... 3-12 3.1.3 Water Quality (Organic Carbon Export, Nutrient and Sediment Trapping) .................................................................................................... 3- 15 3.1.3.1 Organic Carbon Export ............................................................ 3-15 3.1.3.2 Water Quality ........................................................................... 3-16 3.2 FUNCTIONS PROVIDED BY WETLANDS IN MASTERPLAN UPDATE PROJECT AREAS ................................................................................ 3-16 3.2.1 Wetland Impact Areas ................................................................................ 3-17 3.2.1.1 Wetlands Impacted by RSAs, Third Runway, and 154th Street Relocation ...................................................................... 3-17 3.2.1.2 Wetlands Impacted by the Third Runway Embankment West of the Existing Airfield ................................................... 3-18 3.2.1.3 Wetlands Impacted by the Third Runway Embankment within the Walker Creek Sub-Basin ........................................ 3-20 3.2.1.4 Wetlands Impacted by the SASA Development .....................…

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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 [...]