Contributed by Derek Prince, Senior Geologist, PPM Consultants
Imagine a stranger knocking at your door early one morning and as you answer the door, he or she hands you a business card and asks you, “Do you have any wells on your property?” It may be the result of my southern drawl making wells a two-syllable word but most people hear the words, “Do you have any whales on your property?” It takes several minutes for me to explain that I am inquiring about drinking water wells, not drinking water whales.
One of the main objectives of a Preliminary Investigation after a release of petroleum to the subsurface is assessing if there are any drinking water wells located within a limited radius of an underground storage tank (UST) system. It is a rite of passage for every Geologist in the state of Alabama to ask this strange question that is often answered with very strange looks and even stranger questions. I have witnessed several sleepy-eyed, people tilt their heads to the side and intently ask, “Do you mean like humpback whales?” It always surprises me that people do not know where their water comes from when they open the valve on their kitchen sink. After observing a well house on a property, I will ask the residents if the well house that I am pointing at in their yard is active. If they are still not sure, I sometimes inquire if they pay a water bill. They sometimes look at me as though I am some nosey government agent, asking too many questions and wanting money. With some persistence I usually am able to demonstrate to them that their water actually comes from an underground source right beneath their feet.
Identifying water wells for a sensitive receptor survey can be very challenging A water well survey is required by ADEM following a release or suspected release of contamination. It’s an important step to protect human health and the environment. However, this is often the one thing I see most overlooked when taking over sites from other consulting firms. For reference, PPM was retained as the consultant at an Alabama UST Trust Fund site with an active UST incident that had been in corrective action for several years and there were no domestic wells identified by the previous consultant within 1,000 feet of the site. Per ADEM’s request, PPM completed a new sensitive receptor survey, which identified 10 domestic wells within 1,000 feet of the property with several residential properties actively using the shallow groundwater as a potable water source. PPM began collecting quarterly water well samples from five domestic water wells within 500-feet of the petroleum service station. Historically, the quarterly analytical results from the drinking water wells were consistently below detection limits, however, during one of the routine quarterly sampling events, several of the drinking water well samples suddenly indicated petroleum concentrations in the residents drinking water supply. PPM completed a Site Stabilization which included: 1) Notification to all residences located within 500-feet of the site with potential petroleum impact; 2) Provided all residences within 500-feet of the site with access to the public water supply and/or emergency potable water, and 3) Re-sampling of the wells to determine the magnitude and migration of the release as well as to investigate if a new release of petroleum had occurred. Although there was no evidence of a new release at the site, a recent service water leak resulted in a sudden increase of contaminant migration at the site (flushing effect). If these wells and related data had not been discovered, the residents drinking from those impacted wells could have been unknowingly drinking petroleum impacted water, possibly for years.
It can be difficult to find and identify private drinking water wells as they are constructed and sheltered in a variety of ways making it difficult to find, particularly for the untrained eye. Drinking water wells can be derived from shallow hand dug wells that may consist of concrete structures approximately 4-feet in diameter or may have been installed with a drill rig to depths of over 1,200-feet. As shown below, water wells are easily recognizable with a cinder block or brick well house covering the well, well pump, and holding tank for a residential property. Some drinking water wells may lack the typical well house and may be observed as a 4-inch or 6-inch diameter, steel pipe sticking up above the ground surface. Sometimes the pipes may be covered with a bucket or decorative miniature wooden well house. They may be covered with a rock, a piece of wood or an upside-down plastic bucket. One easy way to spot drinking water wells is by identifying the holding tank for the well that is blue the majority of the time. These tanks are easily identified once the well house has become dilapidated and/or has been removed. The well is typically located within a few feet of the water tank.
Possible reasons for consultants not properly identifying domestic water wells may include a lack of understanding of what the wells may look like or possibly only scanning for something that resembles a well house. I believe that fear is a frequent reason that people do not complete a proper well survey. While conducting a receptor survey it is not uncommon to encounter aggressive dogs, snakes or wasps in the well houses, jealous husbands, and even the occasional meth-lab. I believe that most people try to avoid the uncomfortable situation of knocking on a stranger’s door and having to ask if they have any Whales on their property!