Cars line up along School Street in Mansfield Sunday waiting to get a case of water after the town issued a boil order because E. coli bacteria was found in drinking water.

Cars line up along School Street in Mansfield Sunday waiting to get a case of water after the town issued a boil order because E. coli bacteria was found in drinking water.

It has been a while since my school days. Back then, my area of study was civil engineering with a focus on water/wastewater treatment as well as environmental remediation action. I do recall some of the details of how water supply systems work.

Typically it is developing nations, not New England towns, that suffer E. coli contamination problems in their supply.

There are many who have a more contemporary understanding of geologic water sourcing and how aquifers behave, but the idea they can become contaminated and are not an infinite source of water is pretty consistent. Towns like Mansfield source their water from several wells, primarily fed from the Canoe River aquifer. They appear to serve the needs of the town fairly well. But, unlike some residents think, wells are not infinite sources of water.

Everyone is aware this summer has been hot and dry. You can count the rainy days of the past few months on one hand. With the exception of last week’s deluge, it has been a very dry season.

So let’s take a minute and ponder Mansfield’s problem earlier this week: A boil water order due to E. coli in the town water supply. The good news is someone is following what are likely state guidelines for water quality monitoring. The bad news is that E. coli was found in the water supply.

In my 40-odd years of residence, at least in my recollection, this is a first.

While the immediate issue this week was to resolve this health inconvenience, the bigger question is what can be done to prevent recurrence. Of course that starts with uncovering the root cause and identifying which wells were contaminated.

It will be interesting to see what findings are arrived at when the town looks into the source of the E. coli. I’ve got to imagine most folks have a clear idea where E. coli bacteria originate.

Having some understanding of how well water quality could deteriorate, I will offer my two cents.

It is accepted that wells can fail if they are over pumped. The general concept being that if you consider a well is simply a tap into underground water, the more you pump out, and especially if you pump at a rate faster than nature replenishes the outflow, there is likelihood of undesired consequences. Pores that normally feed the well can collapse blocking replenishment.

Undesired minerals might be leached into the well as the source is refreshed. Or there is the possibility of contaminants and surface waste being drawn into the vacated spaces underground.

I am thinking that with the extraordinary dry spell and lack of rain, the town’s water sources have been stressed to the point where some of these undesired effects have occurred.

Thinking about the reasonably heavy rain in the region we had last week, it’s easy to suspect that surface contaminants, like E. coli could have been flushed from the surface to subsurface sources that feed our wells. It’s likely the source of the contaminants was not in Mansfield.

What’s the solution? For starters, the town needs to aggressively address the wasteful practice of ornamental lawn watering.

Officials can start with the lawns of the town hall area and the grass in front of the public safety buildings. Estimates reference about 30% of potable water goes to watering ornamental plantings.

Then, as has been instituted in some towns, water used to irrigate ornamental lawns, regulated by permanently installed sprinkler systems, needs to be metered separately. The rate for that water usage would necessarily be set at a rate that would cover costs of events like what we are now experiencing. Perhaps two to three times the regular domestic rate would be reasonable. I am thinking it is more important to have drinkable water rather than green lawns and prohibitive costs for unnecessary water usage might offer some deterrent.

Additionally, when there are severe shortages, as were witnessed this summer, outdoor lawn watering would be strictly prohibited.

There is no need to water lawns as for most strains of grass, they will simply go dormant and become refreshed when rainfall returns to some normal level.

Vegetable and flower gardens are more sensitive to dry spells but require significantly less watering so their maintenance is not so much an issue.

It will be very unsettling if the town’s Water Department is not able to confirm the source of the contamination because, without resolving the root cause, it is likely recurrences will occur.

Actions during low water periods, like limiting the amount of water wasted to irrigate ornamental lawns, would be a good first step in remediation.

Water, mow, whack and blow. Wonder where’d the water go? Now we know. The lawns are green, but we can’t drink the water.

Bob Foley, a Mansfield resident, former Marine pilot, high school math teacher and engineer, writes here each Friday.