A Historical Perspective of Well Installation

Are there trends that can be found when reviewing state completion reports?

By Andrew McCue

Water well drillers in Massachusetts have been submitting well completion reports for decades.

These reports give descriptions of the soil conditions, water flow, and the details of well construction for the wells they have installed. The cataloging of these reports by the Massachusetts Executive Office of Energy and Environmental Affairs dates back to 1962.

With decades of well completion reports on hand, the question is what can they tell us about how the industry has changed and what influences our industry over time.

General Trends

When examining the database of well completion reports as a whole, a few trends can be observed. First, domestic, irrigation, and monitoring wells are by far the most popular well types installed each year and comprise about 95% of all well completion reports. As shown in Figure 1, completion reports for irrigation and monitoring wells started to become prominent in the late 1980s.

There has been a change in the prominent well types within the other 5% of well completion reports. As shown in Figure 2, from the 1960s through the 1980s there were primarily test wells, public water supply wells, and industrial wells. It wasn’t until the early 1990s that geothermal wells began to become popular.

There are only a few hundred geothermal wells installed each year as opposed to domestic, irrigation, and monitoring wells, which for decades had combined to have consistently more than 1000 annual well completion reports. Irrigation wells have consistently been less popular than monitoring and domestic wells.

The year with most wells installed in Massachusetts in the last 50 years was 2002 with 7804, and the year with the fewest wells installed was 2015 with 2303.

Granger Causality

Granger causality tests were conducted to determine whether an external factor can predict changes in well completion reports. Granger causality is a statistical test used to determine if changes in one variable can be used to predict changes in another.

With a positive Granger causality result, variable A can be used to predict changes in variable B, and it can be said that variable A Granger causes variable B.

When variable A Granger causes variable B, there are a few key statistics to note. First, the statistical test returns a P value. The P value indicates the probability that the null hypothesis is true. A [P] value of .05 indicates that there is a 5% chance that the null hypothesis is true. In the case of Granger causality, the null hypothesis is that changes in variable A do not cause changes in variable B.

In addition to the determination of whether one variable Granger causes another, there is also the order which is entered into the testing parameters. An order in Granger causality is the tested lag between changes in one variable and another. If variable A Granger causes variable B with an order of three years, then there is a delay between changes in variable A and variable B of three years.

There is also the F value that is included in the results of a Granger causality test. The larger the F value, the greater the difference in the means of the two variables than what would be expected by random chance. If the F value is near or less than one, the differences in the means of the tested variables is close enough to be explained by random chance.

The Influence of Rain

The average annual rain in Massachusetts varies from year to year. Since 1988, the most rain observed in a given year occurred in 2018 with 61.51 inches of rain. The lowest average rain observed in the past 35 years was in 2016 with 36.78 inches of rain.

There has been the notion that the amount of rain that is seen each year is indicative of the number of wells that are installed in Massachusetts. To address this notion, rain data was compared against the domestic, irrigation, and monitoring well completion reports.

Statistical analysis shows that in the past 35 years of rain in Massachusetts, Granger causes the irrigation well installation for one and two orders (F values = 8.2445, 4.8173). This means that the average rain can be used to predict changes in the frequency of irrigation well completion reports. The Granger causality for one and two orders signifies there is a delay between the year-to-year changes and changes in irrigation well installation by a year or two.

This lag time makes sense given that the time it takes for permits to be approved can vary by municipality. The memory of a dry year—and by extension burnt-out lawns and seasonal water bans—can impact homeowners deciding to install an irrigation well.

This result supports the notion that rain impacts the number of wells installed each year and demonstrates that there is lag time between rain and installation of new irrigation wells. Statistical analysis did not find any Granger causality between average rain and domestic or monitor well installations.

The Influence of New Housing

There is also the notion that construction affects the number of wells installed.

To address this notion, new private housing units authorized by building permits for Massachusetts data was compared against the domestic, irrigation, and monitoring well completion reports. New private housing units provide a general indicator for construction activity.

When examining the number of new private housing units authorized in Massachusetts since 1988, the year with the highest total was 1988 with 31,766 housing units authorized and the year with the fewest housing units authorized was 2009 with only 6957.

When examining potential causality of new private housing units with the number of domestic, irrigation, and monitoring wells installed in Massachusetts, what was found is that the new private housing units Granger causes domestic well installations for one and two orders (F values = 5.3556, 3.383). This means that new private housing units can be used to predict changes in the frequency of domestic well completion reports.

The Granger causality for one and two orders signifies there is a delay between changes in new private housing units and changes in domestic well installation by a year or two. This lag time makes sense because even though a domestic water well may be part of the construction process, there is often a lag between the permitting stage and when a domestic well is installed.

New private housing units were not found to Granger cause irrigation or monitor well installation.

Conclusion

Examining well completion reports has provided a few key insights into the well drilling industry in Massachusetts.

First, domestic, irrigation, and monitoring wells are by far the most popular well types installed each year and compromise about 95% of all well completion reports. Second, geothermal wells began to become popular in the 1990s.

Additionally, average rain can be used to predict changes in the frequency of irrigation well completion reports, and lastly, new private housing units can be used to predict changes in the frequency of domestic well completion reports.

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Andrew McCue is a third-generation well driller at J.A. McCue Well Drilling in Pembroke, Massachusetts, and has been serving the Cape Cod region for more than a decade. He specializes in the installation and maintenance of residential wells and pumps. He can be reached at amccue@live.com.