TagACC(1548)

This 1991 report by Sheldon and Associates, prepared for the Washington Department of Ecology, assesses wetland mitigation replacement ratios in the Puget Sound region. It evaluates compensation sites where wetlands were restored or created to offset permitted wetland losses, examining how well those sites functioned as replacements. The report provides findings, conclusions, and recommendations on compensation plan design, monitoring, and appropriate replacement ratios for regulatory guidance.

A 1990 environmental assessment by Roy F. Weston Inc. evaluated soil and groundwater quality on an undeveloped Seattle property along the Duwamish Waterway, where Boeing was considering a 50-year lease with Seattle City Light. The study examined areas where dredged sediment from the Duwamish Waterway had been deposited in 1968 and 1985, testing for contaminants including PCBs, pentachlorophenols, PAHs, and metals. Prior sampling had found contaminant levels generally below state-regulated thresholds, and this baseline assessment was conducted to document existing conditions before any lease agreement was finalized.

A May 1989 environmental report from Hart Crowser, Inc. details the installation of three groundwater monitoring wells (WY-1, WY-2, WY-3) near underground fuel storage tanks at the Weyerhaeuser Aviation facility at Sea-Tac International Airport. Soil samples collected during drilling showed no detectable petroleum contamination, and no groundwater was encountered at the site. The report was prepared to help Weyerhaeuser comply with the Port of Seattle's NPDES permit requirements and to assess subsurface soil conditions around the tanks.

Army Corps of Engineers Regulatory Guidance Letter 87-03, dated April 14, 1987, clarifying requirements for Section 401 water quality certification under the Clean Water Act. Covers when certification or waiver is required before Federal permit issuance, the effect of state denial or court voidance before and after permit issuance, and the ‘reasonable period of time’

EPA-600/3-84-099, published October 1984 by the U.S. EPA Environmental Research Laboratory, Duluth, Minnesota. Authored by Anthony R. Carlson, William A. Brungs, Gary A. Chapman, and David J. Hansen from EPA Environmental Research Laboratories in Duluth MN, Narragansett RI, Corvallis OR, and Gulf Breeze FL. Provides protocols for deriving numerical aquatic site-specific water quality criteria by

EPA document EPA 440/5-84-031 establishing ambient water quality criteria for copper, published by the U.S. Environmental Protection Agency Office of Water Regulations and Standards, Washington D.C., pursuant to Section 304(a)(1) of the Clean Water Act of 1977 (P.L. 95-217). Authored by Robert W. Andrew (freshwater) and John H. Gentile (saltwater) at Environmental Research Laboratories in

This document describes input data formats for the VS2D computer program, developed by the U.S. Geological Survey, which simulates fluid flow in variably saturated porous media. It details technical parameters for evaporation and evapotranspiration modeling, including variables for potential evaporation rates, rooting depth, root activity, and atmospheric pressure. The document also outlines time-step control settings used to manage the numerical simulation of subsurface water movement.

This 1980 soil science paper by M.Th. van Genuchten presents a closed-form mathematical equation for predicting how well water moves through unsaturated (partially dry) soils. The equation relates soil-water retention to hydraulic conductivity using a small set of measurable parameters, offering a simpler and more computationally reliable alternative to earlier methods. The model was validated against observed data for several soils with widely varying properties.