Building Pri ncip les Ric hard “Ric k” Stry ker, PE Water, Water Everywhere, Nor Any Drop to Drink In Rime of the Ancient Mariner, Samuel Taylor Coleridge writes, “Water, water everywhere, and all the boards did shrink. Water, water everywhere, nor any drop to drink . . . .” Though he’s writing about sailors stuck at sea who are surrounded by undrinkable sea water, have you ever asked if your camp water supply is just like that: all around you, but not drinkable? Some time back, this column looked at common issues with camps’ potable water systems. Recently, I’ve been getting more and more questions about water systems, so I thought that it was time to revisit some of those earlier points, as a springboard into some new ones. The recap: Almost universally (and I can’t think of even one exception), camps rely on groundwater wells (as opposed to surface waters like lakes or streams) to provide water for camp. That’s because soil itself provides a spectacular treatment mechanism before the percolating rainwater reaches a local aquifer. It acts both as a strainer and a medium for microbes of all kinds to consume or convert contaminants that would otherwise make people sick. Given sufficient percolation depth (which equates to time for the water to travel through it), microbes in the soil consume toxins and unwanted nutrients, and the soil matrix screens particulates. Without any human intervention at all, the water is naturally cleaned and purified. Millions of residential wells, including the one that serves my home, deliver fresh, clean, potable water without any human intervention whatsoever. For these reasons, then, potable water wells should be deep. In many locations, the top fifty feet of a well is isolated from the water-bearing layers beneath specifically to exclude undertreated water from entering the system. Where solid bedrock is the regional geology, steel casing is driven into the rock to seal out the undertreated water. Where the shallow material is gravelly or sandy, a special mineral slurry is injected between the outside of the casing and the ground to create a water-excluding plug. Over time, though, even subtle changes near the well may affect the quality of the water it produces. Earthwork and grading may change surface flow patterns, directing runoff toward the well head (the pipe that sticks up), which may allow unfiltered water to enter the well borehole. Water doesn’t need to flood the top of the well head, either, because where the outside of the pipe and the soil come together is a weakness in the system. Unfiltered runoff can chase the well casing right into the aquifer and contaminate the supply. So it’s very important to account for the location of your wells when there’s development at or around camp and do whatever you must to protect them. Depending on where you are, geology and development can also affect your water quality and available quantity. Particularly where deep soils are sandy or gravelly, installation of new wells nearby may also affect how the water moves below the surface. So be aware of how you and your neighbors situate new water supply wells. Speaking of quantity, there are some pretty problematic misunderstandings about the capacity of wells. Probably the most important point is that there is a fixed amount of water that a well can deliver, called its “specific capacity.” Simply put, you should never ever draw water OUT of a well faster than the water can flow INTO it. Often referred to as “water mining,” this can come about from several situations. The most common include: • Emergency installation of a well pump with a higher capacity than the one it is replacing • The owner (you) wanting more water to satisfy demand 12 CAMPING magazine • March/April 2014 It’s very important to account for the location of your wells when there’s development at or around camp and do whatever you must to protect them. continued on page 14
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