Groundwater is water that is located below the earth’s surface. Over time, water from rain and rivers migrates through the ground and is stored in porous soils and rocks.
Groundwater is an extremely important water resource throughout Australia, with many communities dependent on it for the supply of drinking water, irrigation water and stock water. Many ecological communities and watercourses are also dependent on groundwater for them to function, with the interrelationship between surface water, groundwater and ecosystems extremely important but often poorly understood.
Principal hydrogeology within Australia
To protect the quality and quantity of groundwater resources, therefore, requires careful management actions to be put in place.
A number of projects that I have been involved in have required the development of groundwater management strategies and groundwater monitoring programs to achieve this aim. Some of these have been extremely interesting, especially those involving man-made lake excavations, where the groundwater level and quality characteristics are impacted the lower the excavation goes.
Especially interesting is seeing the cone of depression develop in concert with the extent of the excavation, and the impact of rainfall patterns that further complicate groundwater dynamics.
Unfortunately, groundwater boreholes seem to have an innate ability to get run-over. If there is an excavator, dump truck or scraper working in a five hectare area of works that contains one groundwater borehole, then you can be sure that no matter what high vis paint or flags you put on the borehole, it will still get knocked over. In fact, at one site that I was at monitoring groundwater, of a total of 32 groundwater monitoring boreholes at the site, 30 of them got knocked over! And some of them twice! And this is despite the contractor having to pay to replace each bore they damaged or destroyed.
Groundwater monitoring boreholes also seem to be a prime piece of real estate for some animals. Green tree frogs in particular seem to love to crawl down the stand-pipe and make a cosy little home for themselves, which is often made easier because for some reason the stand pipe end caps always seem to mysteriously disappear.
The other big danger of groundwater sampling is dropping the bailer down the standpipe. This is something that (luckily) I have not yet been able to achieve; I think my time in the Navy learning how to tie knots has come in handy in this regard.
I was at a site once with another fellow that somehow managed to drop the bailer and rope down the stand-pipe. Luckily, we had a bailer recovery kit in the car at the time, which consisted of a fishing line and a number of hooks. He kept at it for the entire time while I sampled the other surface and groundwater sample points and did the O&M at the WWTP, but in the end he did manage to retrieve the bailer out of the standpipe.
To be honest, I’d rather not drop the bailer, and think I’ll save the fishing gear for the weekend!