Monitoring Strategies for Well Systems

Effective monitoring can be a tool that prolongs the overall life of customers’ wells.

By Eric Duderstadt

Illustration of changes in color and turbidity clearly visible over sampling interval.

To discuss the topic of “effective monitoring” we first need to establish a couple of facts.

First, water wells are important assets. A water well not only represents a financial investment, but the water produced is also a valuable resource whether it is being used for consumption, environmental, or industrial purposes.

Secondly, wells are susceptible to a large variety of potential fouling sources. Outside influences from the aquifer, the soil, surrounding land uses, previous contamination events, fluctuating weather patterns, the construction of the well, the way the well is used, and any number of other variables can impact well performance.

These influences can be biological, chemical, or physical in nature and can impact well performance over the life span of a well. Often, a combination of multiple fouling mechanisms is responsible for a well’s decline.

Finally, a rudimentary definition of a healthy well can be: a well that is structurally sound, functioning at an acceptable level, and producing the desired quality and quantity of water.

I think we can agree a healthy well is less problematic than an unhealthy well of equal stature. However, while healthy wells are not any less important than problematic wells, they are often the ones that receive less attention and are often overlooked. This is because they are, at that moment, the ones that present a lower level of urgency. In a real sense, they are “out of sight and out of mind.”

The idea of monitoring a well is not a difficult one in theory, but historically it is difficult to put into practice. The monitoring of a well is not unlike conducting regular maintenance on a vehicle.

Avoiding an Urgent Matter

Probes and instrumentation used for profiling general water chemistry.

We must perform a number of routine tasks on a regular basis to ensure basic requirements are being met so our vehicle can continue to run properly. Some examples of such tasks are changing the oil, checking the tire pressure, and keeping the gas tank filled. While each of these activities on their own is not difficult and does not require a substantial investment of time or money, failure to carry out any one of them can leave us stranded on the side of the road.

So too is the case for water wells. The actions allowing us to take care of our most valuable assets are inherently important because of the investment we have in the assets themselves. Yet failure to accomplish or keep up with important tasks can turn what was previously important into an urgent matter.

To take it one step further, when something as important as a well also takes on a sense of urgency, the culmination of these is often a crisis. A crisis within the well industry can manifest itself as more costly and invasive rehabilitation needs, longer downtimes, or an unacceptable and possibly unsafe water quality.

Bacteria cultures grown within laboratory from well samples being processed for bacterial identification.

In some cases, a crisis in a well may ultimately result in a loss of the well and our asset. The goal of monitoring any well is to avoid the crisis by identifying and adequately addressing potential issues before they become urgent.

Putting Monitoring into Practice

The effective monitoring of water wells can be accomplished using a combination of techniques. Again, many of the monitoring efforts require little time or financial investment, but when used effectively, can provide an increased awareness of the current conditions and result in better management of time and resources in the future.

One of the simplest steps to take is to conduct regular site assessments at the well location. Physically inspect the wellhead and the area immediately surrounding it by looking for signs of vandalism or damage.

Regularly inspect gauges and valves at the wellhead to look for evidence of wear, iron accumulations, erosion from sediments, or malfunctioning equipment that can cause backflow into the well setting.

New areas of staining on concrete floors or surface slabs can indicate elevated levels of iron, manganese, or other minerals in the water. The development of foul odors can also be a good indication that unwanted fouling—in many cases biological in nature—is occurring downhole. Further observation as to whether odors, turbidity, and other unwanted aesthetic characteristics of the water dissipate or remain after extended pumping can also give some indication as to the potential
magnitude of the fouling.

Once the area immediately around the well is inspected, expand the effort to the greater area surrounding the well. Take note of land uses, including the makeup of residential vs. industrial vs. agricultural settings, and any changes that occur.

For wells located close to streams or in areas prone to flooding, it’s often useful to document significant rainfall events if the aquifer is hydrologically in communication with stream levels or receives rapid recharge. Along this line, the surface seal on the well should be routinely inspected and always maintained to make sure surface contaminants from runoff or flooding events do not enter the well.

It’s a good opportunity to conduct a pump test while on site. These tests are used to assess the capabilities of the pump and estimate the performance characteristics of the screen and aquifer.

Measurement of flow rate and the level of drawdown and their comparison allow for the calculation of the specific capacity of a well. Specific capacity is a widely relied upon unit of measurement for determining the productive capacity of the well. Periodically collecting this information over the operational life of a well is helpful in tracking overall performance and the need for maintenance to address blockages occurring in the screen or aquifer.

Concurrent with these efforts, monitoring pump performance over time can also be useful in identifying problems. Increasing power demands related to pump operation may indicate that the flow of water is being constricted or blocked by unwanted fouling mechanisms. It can also signify increased wear patterns on the pumping equipment itself which can be caused by bacterial influences, corrosion tendencies, sediment migration into the well, and other external influences.

Another monitoring method, while perhaps traditionally considered more reactive than proactive in nature, is the close tracking of water quality parameters and subsequent changes in water conditioning practices.

For example, increased fouling upstream of a treatment operation can result in greater demand for treatment products. As such, a significant bacterial infestation in the well could consume fixed chlorine residuals and require a greater chlorine demand during treatment practices. Similarly, increased iron development in the well can place a greater load on filters and decrease run times.

In some cases, if the fouling reaches a high enough level, treatment operations can become overwhelmed entirely and breakthrough of unwanted contaminants can occur, resulting in a greater number of complaints from the end user. However, it should be noted that often changes in water quality only begin to reach noticeable levels after fouling becomes established and reaches a more advanced degree within the well.

Testing of Well Systems

Heavy staining observed at the surface indicating fouling occurring in the well environment.

One of the more effective tools for monitoring wells is the use of routine laboratory testing of water samples. Water samples provide a direct look into conditions present downhole at the time of sampling.

While laboratory offerings can vary greatly in time, cost, and level of detail, the selection of the most vital parameters for a given well and regular testing of those parameters can often be accomplished at an economical cost. Current instrumentation and advances in laboratory equipment also make results obtainable in a much timelier fashion than previously possible.

A laboratory monitoring program might include regular monthly, quarterly, or yearly submittal of water samples, depending on the needs of the well and the role it plays within a system.

At a minimum, testing should include some assessment of the overall chemical congestion and biological load within the system. General water chemistry parameters can include pH, total dissolved solids (TDS), alkalinity, hardness, and oxygen reduction potential (ORP), as well as common scale-forming or deposit-forming minerals such as calcium, iron, and manganese.

For biological monitoring, traditional plate counts as well as more modern adenosine triphosphate (ATP) assessments can be used to quantify the overall bacterial population. Testing for anaerobic, iron-oxidizing, sulfate-reducing, and other problematic groups of bacteria can also be done simultaneously to identify potential impacts relating to the aesthetic quality of the water.

Finally, a microscopic evaluation of water samples offers a simple yet effective way to identify larger microbes, plant material, algae, and other inorganic debris which might signal a surface water connection.

Regular measurement of these and other select parameters can allow scientists, owners, and operators to identify and track trends that develop and better plan for future maintenance needs.

Regardless of the monitoring efforts being used, laboratory data and numerous studies have overwhelmingly supported the notion that wells should remain active or see at least regular operation as much as possible.

Regular operation or routinely exercising a well can greatly reduce the impacts of aggressive chemical tendencies on the well and discourage bacterial growth by hindering their ability to attach themselves to surfaces and establish biofilm formations. Given these tendencies, monitoring techniques should coincide with the operational schedule of the well to identify fouling related to any irregularities or interruptions in operation.

Likewise, reassessment following rehabilitation or other related maintenance efforts can also be beneficial in establishing new baselines going forward.

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Water wells should be monitored regularly to keep them operating at optimal capacity. Water analysis should be balanced with observations of the physical integrity of the well, the operational effectiveness of the well, the quality of the water being produced, and any noted challenges being faced in water treatment.

While monitoring practices may not produce an immediate impact, they can be monumental in helping ensure the long-term operating efficiency of the well and identify fouling before it reaches severe levels.

Early identification of problems and proactive maintenance procedures are more likely achievable at a reduced fiscal investment and time commitment when effective monitoring efforts are in place.

Perhaps the monitoring of wells is not unlike the recognizable slogan used for a popular insurance company: “Fifteen minutes can save you 15 percent on . . . .”

With a little bit more care and investment, we can all make monitoring a tool that helps prolong the overall life of our customers’ wells and preserve the resources at our disposal.

Find Books on Water Treatment in the NGWA Bookstore
There are several books available in the NGWA Bookstore that focus on matters relating to water treatment, water well technology, and more. Included is Operational Stage of the Well, whose coauthor is Michael Schnieders, PG, PH-GW, the author of the first installment of this series. The book goes over various factors of well deterioration and how they impact well operation and maintenance. Visit the NGWA Bookstore section on water treatment.

Eric Duderstadt is an environmental biologist with Water Systems Engineering Inc. of Ottawa, Kansas, where he works as a consultant. He earned his bachelor’s degree in biology at Ottawa University in 2007 and has since become certified as a corrosion technician within the National Association of Corrosion Engineers. He also works within the firm’s research department and investigative laboratory centering on microbiology and chemistry. Duderstadt can be reached at eduderstadt @h2osystems.com.