Water, water everywhere - Building Principles

Camping Magazine, Sept-Oct, 2002 by Rick Stryker

Water from the tap or showerhead is something many of us take for granted. Until, of course, it's not thereon demand. Because of their inherent remoteness, camps and conference centers are particularly vulnerable to the problems caused by a water outage. Most camp facilities' staff have a basic understanding of their particular system, but may not be especially well versed on how small changes in the system can have far reaching effects. Similarly, many executives and owners are asked to make decisions about their systems without really understanding how the choices can affect operations in the long run.

Let's look at several of the basic design and operating parameters for small water systems including estimated daily demand, the sources, and types of supplies and methods for supplying pressure.

How much do we need?

Most states have adopted conservative design figures between forty and eighty gallons per day per person at resident camps for estimating both the required fresh water supply volume as well as the volume of wastewater expected to require treatment. In most areas, if your organization can provide historical water usage, those "real" figures can be used when designing new components of either system. For those reasons, we strongly recommend that all water systems be metered and monitored. Without site-specific data, we normally assume conservatively that each person will consume eighty gallons per day. This usage includes bathing, food preparation, and regular consumption. For example, if your camp capacity is 300, we would estimate your average daily demand at 300 people X 80 gallons per person = 24,000 gallons per day

Water Supply

There are two facets of this issue to be considered. Either a camp's water comes from a public source such as a village or town by way of a water supply line or it is self-sufficient, relying on sources within its own boundaries. Both sources have issues with which the camp or conference center executive must grapple.

Public supply

This is a mixed bag of benefits and shortcomings. On the plus side, the customer is typically not required to monitor the quality of the water nor is it required to submit the water for tests. In today's climate of government paperwork, this freedom can certainly be a blessing. There is also the added benefit of being connected to a proverbial "endless supply." Anyone who has been at camp when the well "went dry" or the well pump died can certainly appreciate this!

For the camp that is being approached (or in some cases, has been directed) to connect to a public supply network, there are often concerns about whether the amount charged is commensurate with the volume actually used. In some cases, the camp has negotiated a flat fee for which it receives water for its operating season. In light of recent drought conditions in many regions, this type of arrangement has become increasingly rare. For the organizations that still operate this way, we suggest that the days are numbered. At the very least, the camp should expect to see fairly large increases in the fee. This is the method by which the seller of the water will encourage conservation measures. Most users of public water are metered, with the customer paying a regular fee per thousand gallons of water used.

Private supply

Historically, surface water has been available for water supplies. However with the increased population in surrounding areas, surface waters are more and more contaminated with pollutants and bacteria. Even in remote areas, the most pristine appearing water likely contains cysts and pathogens generated by wildlife. Without advanced and very expensive treatment, this water does not meet potability standards of most state health departments. In fact, most wells whose construction does not physically prevent the entry of surface water runoff are not considered acceptable sources.

Operating a "nontransient, community water supply" has certain monitoring requirements, which are imposed by state health agencies and enforced/monitored by local ones. This normally involves very basic periodic sampling for indicator organisms such as coliforms. systems which operate under the influence of surface waters (as described above) often have additional testing requirements to ascertain whether other contaminants have entered the well.

Today, most camps water supplies are underground in the form of wells. The depth and construction of these sources varies by subsurface geology, but in general, the operating principles are the same. A hole is either drilled or dug through the surface layers of earth until a water bearing layer (or strata) is encountered. The amount of water that enters the hole will be dependent on the size of the hole, the physical size of the "underground pond" (or aquifer), and the characteristics of the material through which the water flows.

Water In = Water Out

It's important to consider that this describes the property of the well known as "specific capacity." We have encountered several facilities where a larger well pump was perceived as a solution to a water supply shortage. The capacity of the well can only be determined by performing a test known as a "drawdown," or "pumping test." Typically, a fairly high capacity pump is temporarily installed in the well and is connected to a water flow meter at the top of the well As water is drawn from the well, the depth from the top of the well casing to the water level is measured at regular time intervals. The rate at which the water is pumped out is adjusted until the water level in the well does not fall further from one measurement to the next, indicating that water is being removed from the well at the same rate as it is flowing in. This test is conducted over a fairly long time period, twenty-four hours or more. When the pump is turned off at the end of the test, measurements are taken and recorded to determine th e rate at which the well "recovers" from being pumped. This data is used to determine how much water is physically available from that particular well, and to set the depth at which the final pump should be set. For smaller wells (typically single family residences), the well driller skips this step and uses equipment on the drilling rig and makes a best guess. For a large organization with a similarly large water demand, however, this is a particularly important procedure and should not be skipped.