The Oregon Water Quality Decision Aid (OWQDA) is
a first-tier screening tool that allows you to make a broad
determination of the likelihood that a specific chemical,
when applied to a specific Oregon soil, will move through
the soil and contaminate groundwater. This determination
is called the groundwater vulnerability rating.
Estimates of mass transfer timescales from 316 solute transport experiments reported in 35 publications are compared to the pore-water velocities and residence times, as well as the experimental durations. New tracer experiments were also conducted in columns of different lengths so that the velocity and the advective residence time could...
Spreading livestock and poultry manure on crop and pastureland is a way to reclaim the value of the plant nutrients in manure. This practice is the most popular and widely recommended way to utilize these manures. Nitrogen and phosphorus are the nutrients of greatest value in manure and are the...
The procedure described in this publication helps
you assess the potential for any specific pesticide
to travel through any specific soil to reach
groundwater.
Oxygen is often the rate-limiting factor in aerobic in situ bioremediation. This paper investigates the degree to which air or oxygen gas can be emplaced into the pore space of saturated porous media and provide a significant mass of oxygen. Column experiments were performed to test three emplacement methods: direct...
We investigated multiple-rate diffusion as a possible explanation for observed behavior in a suite of single-well injection-withdrawal (SWIW) tests conducted in a fractured dolomite. We first investigated the ability of a conventional double-porosity model and a multirate diffusion model to explain the data. This revealed that the multirate diffusion hypothesis/model...
Published August 1989. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
The study area lies north-northeast of Crater Lake National Park and is covered by 2 to 3 m of pumice deposited during the climactic eruption of Mount Mazama approximately 7700 years before present. The pumice deposit hosts unconfined, seasonally connected, perched aquifers that support groundwater dependent ecosystems at points of...
Four factors govern the potential for groundwater
contamination by pesticides passing
through the soil:
• Properties of the soil
• Properties of the pesticide
• Hydraulic loading on the soil
• Crop management practices
