About the Class

In this session, you will gain a basic understanding of groundwater science including aquifers and aquitards, risks to ground water and local groundwater availability. You will learn about the genesis and function of our aquifers and aquitards. You will also learn about the risks to our water resources, such as contamination and over-use, and how government agencies work to protect our water resources. The presentation will also provide details regarding local groundwater availability and issues.

Follow-up session questions and answers:

Our water coop is planning to drill another well in 5-7 years. We have selected an area and are ready to select existing wells for testing aquifer volume and quality. In your opinion would you wait until we are closer to drilling or go ahead and do the test now. The big question will earthquakes affect an aquifer.
I would suggest that testing could be conducted at any time, and there might be some benefit to testing sooner rather than later. Testing now, and then perhaps a quick check of a well or two in 5-7 years when you are ready to drill could provide some information as to whether or not the aquifer quality or quantity is changing. As to your question about earthquakes, they certainly can affect an aquifer, but I wouldn't let that relatively remote possibility deter you in your quest for reliable water.

I heard our aquifer in the Greenbank area extends far to the east under Holmes Harbor. Is that accurate?
The primary aquifer in the Greenbank area occurs at approximately 25 to 50 feet below sea level. Topography in Holmes Harbor adjacent to Greenbank has depths of 150 to 200 feet below sea level. So the primary aquifer does not extend beneath Holmes Harbor, but instead outcrops a short distance offshore.

We heard a talk this morning about plastic microfibers washing into the ocean through, among other channels, effluent from washing machines. Many of us who live near the water on Whidbey have spetics. Question: Do microfibers get into our aquaphors and therefore into Puget Sound?
This (microplastics in groundwater) is an area of study that is relatively new, with many unanswered questions. My opinion (fwiw) is that although microplastics might be mobile in some groundwater environments such as karst (limestone) or fractured igneous and metamorphic rocks, they are less likely to be found in unconsolidated sand and gravel aquifers such as those found in Island County. This is because the sand and gravel media act as a filter system for particulate matter.

If dog poop is buried a few inches deep above an aquifer (1 dog/acre), would it affect the water quality?
At a density of 1 dog / acre, I do not believe there would be a noticeable impact to groundwater quality. Higher animal concentrations can have impacts.

Is there an aquifer below Cultus Bay?
Cultus Bay is quite shallow, so it is possilble that aquifers in the area do indeed extend beneath the bay. In fact there are some deep (400+ ft) wells on Sandy Hook (which juts out into Cultus Bay) that have good, low chloride water quality.

Please speak to arsenic levels in private wells and how to best mitigate- resort road area
Approximately 15% of the wells in Island County exceed the USEPA maximum contaminant level for arsenic (0.01 mg/l). Rather than trying to provide enough detail here to be useful, I'll provide some links to some good information: Arsenic and You, Arsenic and Your Private Well & Arsenic in Your Drinking Water - Just the Facts for Consumers​​.

How accurate are the water well reports? Are all wells documented/reported? Is this data added to the EPA Watershed database?
There likley is considerable variability in the quality of water well reports. I think that efforts on the part of DOE to monitor and educate well drillers have resulted in an improvement both in the level of detail and quality of the data reported. Not all wells are documented, especially older wells. I'm not familiar with the EPA Watershed database, so I cannot comment on what is there.

Does JEFFERSON County have a "well viewer application" online that is similar to yours in Island County?
I am not aware of Jefferson County having a water well database, although I believe some of the WRIA's within the county may have something. The State Dept. of Ecology (DOE) does have a water well database which contains information state-wide; I'll provide a link to the right:

Does the saltwater interface move with tides?
It does indeed, wells completed within the zone of diffusion typically exhibit higher chloride concentrations during high tides. Some water systems with intrusion problems have installed computers that only activate well pumps during low tides to mitigate intrusion problems.

Can the water level elevation data be used to predict flooding risk during high precip. events?
Groundwater elevations do not typically have much to do with surface water flooding, especially not transient (precipitation related) flooding. When groundwater levels rise above land surface, springs and seeps are developed. Although these springs and seeps can contribute to flooding, groundwater levels do not typically respond to short-term precipitation events, so groundwater discharges will typically be relatively constant.

When the wells are placed in areas with a higher water levels as a way to avoid intrusion with existing wells, are those existing wells still usable most of the time? If not, what happens to them?
It depends on how badly intruded the aquifer is. There are cases where intrusion problems are bad enough that the wells are no longer useable. In those cases, the water systems typically look for new locations to drill (further from the shore) or shallower completion depths to mitigate intrusion. Reducing pumping rates (and compensating through addition of storage) can also sometimes be of use in reducing intrusion.


He worked seven years in the Groundwater Section of the Illinois State Water Survey, a division of the Illinois Department of Natural Resources, five years at the Olympia, WA office of Science Applications International Corporation (SAIC), environmental division (consulting). Doug came to Island County over 20 years ago and worked for twelve years as the County's first Hydrogeologist, leaving the county in 2008 to work for Pacific Groundwater Group in Seattle. Doug returned to county employment in February of 2012. He is married and has two children.

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