EXH1215048122

5808 Lake Washington Blvd. N.E., Suite 200 Kirkland,Washington 98033 December 2000 556-2912-001 (03) h_ 0_'8123 - TABLE OF CONTENTS Pace EXECUTIVE SUMMARY .................................................................................................................vii 1. INTRODUCTION ................................................................................................................ 1-1 1.1 PROJECT DESCRIPTION ...................................................................................... 1-1 1.2 KEY PROJECT ELEMENTS .................................................................................. 1-2 1.2.1 Runway Safe_y Areas and Relocation of South 154_ Street ....................... 1-2 1.2.2 New Third Runway ...................................................................................... 1-5 1.2.3 Borrow Areas ............................................................................................... 1-5 1.2.4 South Aviation Support Area ....................................................................... 1-5 1.2.5 Overview Of the Mitigation Plan. ................................................................ 1-5 1.3 WETLAND DELINEATION .................................................................................. 1-8 1.4 SIGNIFICANT WETLANDS AVOIDED BY MASTER PLAN IMPROVEMENTS .................................................................................................. 1-9 2. METHODS ...........................................................................................................................2-1 2.1 IMPACTS TO WETLAND AREA ......................................................................... 2-I 2.1.1 Direct Impacts .............................................................................................. 2-1 2.1.2 Indirect Impacts ............................................................................................ 2-1 2.2 IMPACTS TO WETLAND FUNCTIONS ............................................................. 2-1 2.2.1 Background .................................................................................................. 2-1 2.2.2 Assessment Methodology ............................................................................ 2-3 3. RESULTS ............................................................................................................................. 3-1 3.1 EXISTING WETLAND FUNCTIONS ................................................................... 3-1 3.1.1 Biological Functions .................................................................................... 3-1 3.1.2 Physical Functions ..................................................................................... 3-11 3.1.3 Water Quality ............................................................................................. 3-11 4. IMPACT ANALYSIS ........................................................................................................... 4-1 4.1 PERMANENT IMPACTS ....................................................................................... 4-1 4.1.1 Runway Safety Areas ...................................................................................4-1 4.1.2 Third Runway ............................................................................................... 4-2 4.1.3 Borrow Areas ............................................................................................... 4-5 4.1.4 South Aviation Support Area ....................................................................... 4-5 4.1.5 Other Master Plan Update Improvements ................................................... 4-6 4.2 TEMPORARY CONSTRUCTION IMPACTS ...................................................... 4-6 4.2.1 Construction Runoff. .................................................................................... 4-6 4.2.1.1 Discharge Standards .................................................................. 4-7 4.2.1.2 Treatment BMPs ........................................................................ 4-7 4.2.2 Other Potential Construction Water Quality Impacts................................ 4-10 4.2.3 Wetland Alterations During Construction ................................................. 4-11 4.2.3.1 Runway SafetyAreasandRelocationofSouth154= Street........................................................................................4-15 4.2.3.2 ThirdRunway ..........................................................................4-15 Wetland Funcnonal Assessment and Impact Analys_s December 2000 Seattle-Tacoma internatwnal Awport ii 556-2912-001 (03) Master…

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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 [...]