Today is World Water Monitoring Day. This day was established in 2003 as part of a global educational outreach programme designed to build public awareness of the protection and monitoring of water resources and availability.
But, what does this have to do with groundwater?
When we start changing the surface of the Earth with major earthworks, drilling, mining and tunnelling activities, and just about every other activity that is part of the construction industry, it is important to monitor a site’s local groundwater. This monitoring can provide valuable information for project designers in terms of foundation design or save money when conducting a drilling project. If groundwater is not respected and correctly managed, deterioration in its quality can lead to a series of ecological, financial and even legal problems down the line.
A recent example in the news was Glastonbury Music festival, the organisers of which were court ordered to pay £31,000 after 20,000 gallons of untreated sewage escaped from a temporary storage tank into the Whitelake River. The spillage was not directly into the river, the storage tank was underground and the sewage went into the surrounding soil; however, it still managed to “effectively wipe out the local trout population” by making its way into surface water via flowing contaminated groundwater.
So how do we monitor groundwater?
You drill a borehole and install a plastic pipe that enables natural groundwater to build up inside. A technician then takes samples of the water and measures its level.
A more technical explanation…
More specifically, you ask a drilling contractor such as Structural Soils to drill a borehole to the desired depth. Then you install a plastic (high-density polyethylene) pipe with a slotted section at the bottom (this response zone can vary in length and depends on what the engineer wants to achieve). The borehole is then sealed with bentonite pellets to stop soil ingress from the surface. Once the pipe is installed, the natural groundwater will flow (or percolate) through the ground and into the slotted piping. The water level will rise and fall over time, especially in tidal areas. Ground gas can also be monitored at the same time if appropriate equipment is installed. If monitoring of water levels is required several times an hour, a data logger can be added to the system from whence the data can be downloaded later.
A technician goes to the site to monitor the groundwater level or collect water samples to send to a laboratory, such as the UKAS accredited Envirolab, for chemical testing. The technician may also note evidence of oil (hydrocarbon) contamination.
The data are used to assess any changes to the groundwater because of previous or planned construction projects. The consequences of any undesirable changes could be the development of remediation plan to mitigate and limit any damage to a site’s groundwater or even to the greater area’s water table.
This explanation is rather simplified, but the point you need to take away is that water is life. We need to respect it and do everything we can as an industry to preserve it; this includes considering groundwater monitoring.
To learn more about our groundwater monitoring services, please contact Charles Mintowt-Czyz.