TagPCHB(607)

Exhibit 2141 was not present at time of scanning. Administrative Record number AR 034564.02. No substantive content available; placeholder page only.

This Washington State administrative regulation establishes rules for 'mixing zones,' which are designated areas in bodies of water where pollutant discharges are allowed to mix and dilute before meeting water quality standards. The rules set strict size limits for mixing zones in rivers, estuaries, lakes, and ocean waters, and require that dischargers apply all available pollution-reduction technology before a mixing zone is approved. Special provisions are also included for storm water discharges and combined sewer overflows.

Handwritten notes outline eight key discussion points related to a mixing zone (MZ) study, including an examination of stream dynamics, regulatory questions about MZ implications under NPDES permitting, and how to weigh evidence for defensibility. The notes raise questions about whether mixing zones are appropriate at all, and whether existing regulations are flexible enough to accommodate site-specific MZ conditions. A final point flags that mixing zones near water quality listing designations will be a particularly difficult policy 'sell.'

This document outlines regulatory problems and compliance points for stormwater discharges into Washington State surface waters, focusing on where discharges must meet water quality standards. It identifies four key unresolved issues, including the lack of an approved design storm for mixing zones and undefined critical receiving water conditions. Various example situations are provided to help determine the exact location where stormwater discharge compliance must be measured.

This technical document describes a mixing zone analysis for stormwater discharge from the 3rd Runway North at Sea-Tac Airport into Miller Creek, designated as Basin SDW-1. The analysis uses design storm modeling with various rainfall scenarios (2-year/2-hour, 2-year/72-hour, and 3-year/72-hour events) to calculate effluent flow rates for both acute and chronic water quality criteria. Stormwater from the basin's approximately 128 acres of pervious and impervious area is routed through a detention pond before discharge, with outflow rates determined by a storage-discharge rating curve.

Exhibit 2084 from Administrative Record AR 033383.01 was not present at the time of scanning. This is a placeholder document indicating a missing exhibit. No substantive content is available.

This document, identified as AR 024333, has been officially withdrawn and contains no substantive content available for review. It is part of the administrative record but has been removed from public access, leaving only a placeholder page indicating its withdrawn status.

This draft document from Washington State's Department of Ecology outlines requirements for a Low Flow Technical Report and a Low Flow Operation Plan related to MPU development activities. The Technical Report must include all calculations, engineering analyses, and hydrological studies needed to address low flow impacts, and must be stamped by a licensed Washington civil engineer. The Operation Plan must detail how stormwater and groundwater will be managed to mitigate those impacts, including maintenance procedures, performance standards, and methods to ensure those standards are met.

This document is the professional curriculum vitae of Dyanne Sheldon, principal of Sheldon & Associates, Inc., a Seattle-based wetland ecology consulting firm. Among her relevant work, she co-authored both the Sea-Tac Airport Wetland Inventory and the Sea-Tac Airport Wetland Management Plan in 1991 for the Port of Seattle's Environmental Management Section. Her broader expertise spans wetland delineation, habitat restoration, environmental planning, and regulatory compliance across the Pacific Northwest.

This document provides a professional biography and project portfolio for Amanda Azous, an environmental scientist and sole proprietor of Azous Environmental Sciences based in Washington State. Her work focuses on wetland delineation, ecological restoration, watershed analysis, and land use planning, primarily in the San Juan County and Puget Sound regions. While her expertise informs broader environmental policy in Washington State, this document contains no information directly related to Sea-Tac Airport noise policy.