Department of Ecology
Committees, Boards, and Workgroups

The Green-Duwamish pollutant loading assessment (PLA) will identify sources of pollution in the Green-Duwamish watershed and strategies to reduce those sources. We're partnering with the U.S. Environmental Protection Agency (EPA) to conduct this multi-year project.

2021 meetings

Technical Advisory Committee Meeting #16 - July 14, 2021

• Agenda
• Meeting notes
• Watershed model update, management scenarios, HSPF calibration results

Technical Advisory Committee Meeting #15 - May 12, 2021

• Agenda
• HSPF model calibration update
• HSPF watershed toxic model calibration results
• Management scenarios table
• Meeting minutes (including links to more presentations)

2020 meetings

Technical Advisory Committee Meeting #14 - February 11, 2020

• Agenda
• Project Updates
• HSPF Model Development and Calibration
• Preliminary HSPF Outputs
• Meeting Minutes

PLA QAPP 2020

• Draft Revised QAPP
• King County Track Changes
• King County Comments
• CIty of Seattle Comments
• Ecology Response to Comments

2019 meetings

Technical Advisory Committee Meeting #13 - August 21, 2019

• Agenda
• Project Updates - Ecology
• Management Questions Summary Updates - Ecology
• Segmentation Handouts
• Meeting Minutes 

Technical Advisory Committee Meeting #12 - April 10, 2019

• Agenda
• Project Updates - Ecology
• Management Questions Summary - Ecology
• QAPP updates-HSPF development - Jeff Burkey, King County
• Discussion of Receiving Water Modeling Approach - Ecology
• Empirical Loading Analysis - Ecology
• Air Deposition - Kevin Schock, King County
• AIr Depositon Handouts
• Groundwater Data Analysis - USGS

2018 meetings

Technical Advisory Committee Meeting #11 - June 6, 2018

• Agenda and Meeting notes
• Overview - Ecology
• Receiving Water Fate and Transport Model Development Update - Ecology
• Mass Balance Equation Handout
• Sensitivity Analysis Handout Part 1 and Part 2
• Screening Analysis Presentation

2017 meetings

Technical Advisory Committee Meeting #10 - November 1, 2017

• Agenda and Meeting notes
• Presentation - Ecology
• Watershed Model Development handout - Ecology
• Overview of the Salish Sea Model - Tarang Khangaonkar, PNNL
• Salish Sea Model presentation - EPA​​
• PLA Draft Scenarios - Ecology

Technical Advisory Committee Meeting #9 - March 15, 2017

• Agenda and Meeting Notes

Presentations:

• Project Overview & Wrap Up – Ecology
• LSPC Model Development and Calibration – TetraTech
• PCB Congener Study Factor Analysis Results – Dr. Lisa A. Rodenburg

Interested Parties Meeting #2 - March 15, 2017

• Agenda & Meeting notes

Presentations:

• Agenda & Next Steps – Ecology
• Project Overview and Update – Bo Li, Ecology
• LSPC Watershed Model for Flow – Tetra Tech
• Polychlorinated Biphenyls (PCB Overview) – Ecology
• PCB Congener Study Factor Analysis Results – Dr Lisa A. Rodenburg
• Finding and Fixing PCB Sources – Ecology

Previous Meetings (2014-2016)

The TAC started in 2014. Our first interested parties meeting occurred in 2015. Participants provided input on existing water quality monitoring data, modeling parameter selection, modeling boundaries, and the overall technical direction. Please find summaries, agendas, and presentations for these first meetings below.

In 2016, the project team developed a Quality Assurance Project Plan (QAPP) for modeling with an emphasis on the hydrologic models.

TAC Meeting #1 - Dec. 10, 2014

• Agenda
• Meeting summary
• Technical Approach, Existing Information presentation - Tetra Tech
• Project Overview and Regulatory Context presentation – Ecology and EPA

TAC Meeting #2 - Feb. 19, 2015

• Agenda
• Meeting summary
• Project Objectives, Work Plan, Existing Data & Model Evaluation presentation

TAC Meeting #3 - March 19, 2015

• Agenda
• Meeting summary
• Refine Data and Model Evaluation Memo presentation
• How Do We Decide What Pollutants to Model presentation

TAC Meeting #4 - April 16, 2015

• Agenda
• Preliminary Parameters, Existing Green River Data (King County), Data Gaps & Pollutant Groupings presentation
• Meeting Summary

TAC Meeting #5 - June 18, 2015

• Agenda
• Meeting summary
• Candidate Parameter Selection, Data & Knowledge Gaps for Models Presentation

TAC Meeting #6 - July 16, 2015

• Agenda
• Meeting summary
• Model Development Presentation

TAC Meeting #7 - April 6, 2016

• Agenda
• Meeting #7 summary
• PLA Project timeline

Presentations:

• Project Overview, QAPP Status, Phasing & Next Steps – Ecology, EPA
• LSPC QAPP – TetraTech
• EFDC QAPP - TetraTech
• Food web model and data management – TetraTech

TAC Meeting #8 - Oct. 5, 2016

• Agenda
• Meeting #8 summary

Presentations:

• Project Update, Green River Study Update, Next Steps – Ecology, EPA
• Set up & Development of LSPC Model for Hydrology - TetraTech

Interested Parties Meeting #1 - May 28, 2015

• Meeting Agenda
• Meeting Summary

Presentations:

• Status of the Green-Duwamish Watershed: An overview on what we know about water and sediment quality, pollutant loading, and why it’s a problem
• Restoring the Green-Duwamish, an overview of current efforts in the watershed
  • Green-Duwamish Strategy - Sarah Ogier, King County
  • Federal Urban Waters Initiative - Tracy Stanton, Urban Waters Federal Partnership
  • WRIA 9 Watershed Ecosystem Forum - Elissa Ostergaard, King County
  • Lower Duwamish In-waterway Cleanup - Elly Hale, U.S. EPA
  • Lower Duwamish Source Control - Ron Timm, WA Dept. of Ecology
• An introduction to the Pollutant Loading Assessment (PLA)
  Background on the role of the PLA within the broader management strategy for the watershed, key policy questions being considered, the TAC process and its progress to date, and timeline for development
• Next steps
  An overview of what’s next in the PLA development process and opportunities to stay informed and provide feedback

Handouts:

• Green-Duwamish PLA overview
• Green-Duwamish PLA goals and objectives
• Proposed parameters list
• Comment form