Mar 022010

The Transition Town Movement likes to talk about sustainability. What are we trying to sustain? First and foremost: food and water. Even without a passenger ferry islanders will need food and water. Both are precious resources.

“In 1997, the U.S. Geological Survey (USGS), in cooperation with the San Juan County Conservation District, studied the possibilities of seawater intrusion on the Island and found that 46 percent of 185 freshwater samples had chloride concentrations indicating seawater intrusion.” The geology of San Juan Island isn’t that different from Lummi. Seawater intrusion of our wells is more than a probability.

If no man is an island, then no well operates in isolation. “Withdrawing freshwater from a well affects not only the location of the transition zone around that well but also the location of the Island’s regional transition zone. Thus, pumping wells, whether shallow or deep, no matter what their locations, will affect the whole Island’s fresh-water system.”

When you pump out fresh water rapidly, you lower the height of the freshwater in the aquifer forming a cone of depression. The salt water rises 40 feet for every 1 foot of freshwater depression and forms a cone of ascension. Intrusion can affect the quality of water not only at the pumping well sites, but also at other well sites, and undeveloped portions of the aquifer.”

There are lots of landowners who want to capitalize on their holdings and no one can blame them for that. Some of us might not use our water as efficiently as we should  But it seems obvious that continuous drilling and pumping of wells is not a sustainable practice over the long term without developing strong conservation measures and alternative sources of water. There is no doubt a tipping point for the amount of water that can be pulled out of the ground.

The San Juan Island Ground Water Study did have some recommendations to make. They said:

“Seawater intrusion on (the) Island can be minimized by water conservation, efficient well construction, and by judicious well-operation practices like these:
– Using such water-conserving devices as low-volume plumbing fixtures and toilets.
– Keeping outdoor watering to a minimum.
– Reusing or recycling water when possible.
– Augmenting fresh ground- water recharge by, for example, using surface ponds to slow surface runoff and raise infiltration rates.
– Constructing wells that do not penetrate deeper below sea level than necessary.
– Sizing pumps for lower pumping rates and minimizing lengths of pumping cycles.
– In multiple-well systems, pumping wells alternately.”

A Transition Movement on Lummi Island would need to have water conservation as part of its mission.


  One Response to “Peak Water”

  1. How’d I miss this one. Great graphic.
    As part of my mission for the Emerg.Prep group, I plan to review our Hydraulic studies, and recent testing for seawater intrusion of Island wells.
    Yes, it’s a precious resource, and should be conserved.

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