Groundwater monitoring is an essential activity, playing a critical role in mining and construction, as well as environmental and water resource management.
It enables a diverse range of functions, from understanding load-bearing capacity to assessing the quality and volume of drinking water. This makes it an indispensable component of a variety of projects.
This article will help you understand the tools available to identify various groundwater features. It explains how piezometers and monitoring and observation wells work and which sectors and activities they are best suited to.
It offers a comparison between a piezometer vs monitoring well vs observation well to help you make the right choice for your project, whichever sector you are working in.
What Is a Piezometer and When to Use It?
A piezometer measures the pressure of pore water (the piezometric level) in the ground.
Pore water is the water located between gaps or ‘pores’ between soil, rocks and other particles. It’s important to understand the piezometric level since pore water reduces the load-bearing properties of underground material. For example, on a construction site, high levels of pore water could make a structure unstable and unsafe.
A standpipe piezometer consists of a filter tip joined to a tube with a perforated bottom, encased in a pipe.
It works by measuring the height to which fluid rises against groundwater pressure to a determined point. Groundwater pressure forces water inside the tube, and a reading is then taken.
Other types of piezometers are available, notably the vibrating wire piezometer that measures pressure using a tensioned wire. The frequency of vibrations caused by groundwater pressure is measured and converted into electrical signals, which can then be read.
Piezometers are used to:
- Measure pore water pressure in the ground, foundations or concrete structures to help determine load-bearing capacity
- Observe groundwater pressure within pipes and dams
- Understand the flow and level of groundwater in a given area
- Identify seepage patterns
What Is a Monitoring Well and When to Use It?
As its name suggests, a monitoring well is used to observe the features of groundwater by regular collection of samples, which are then sent to a lab for analysis. They detect contaminants in groundwater and measure its availability too.
In addition to observing groundwater, monitoring wells can analyse the aquifer, the underground rock that contains and releases water.
Monitoring wells are generally constructed of stainless steel or PVC and placed into the groundwater table by drilling methods.
They are typically used to assess drinking water quality and in mining operations to ensure their safety and that of the surrounding environment. In fact, monitoring wells are useful on any sites that may be at risk of pollution by chemicals or petroleum products. They can also assess the direction of groundwater flow.
Monitoring wells are a good choice for long-term groundwater level data collection because, once in situ, they are stable and offer a way to collect samples as often as required.
Monitoring wells are a good choice for:
- Detecting contaminants in groundwater
- Helping with drinking water management
- Offering a short-, medium- or long-term means to collect samples
- Helping with understanding groundwater level changes over long periods (this process helps with water management, as it can identify which sources are at risk of being overused)
You may also like: What Are Monitoring Wells?
What Is an Observation Well and When to Use It?
The terms “observation well” and “monitoring well” are often used interchangeably, but they are not quite the same thing.
Observation wells are subtly different from monitoring wells. The primary role of monitoring wells is to enable groundwater level measurement and sample collection. Meanwhile, the main function of observation wells is to allow users to understand groundwater conditions without necessarily gathering samples for analysis (although they can also provide this function).
The design of observation wells is usually simpler and doesn’t feature the perforations of monitoring wells that allow water to enter.
Observation wells are often a good choice to:
- Observe natural fluctuations in groundwater levels
- Detect groundwater flow
- Learn about changes in groundwater levels over long periods
- Help with water resource management
The fundamental difference between an observation well vs a monitoring well is that observation wells are more suitable for continuous groundwater monitoring. Meanwhile, monitoring wells are the better choice for collecting samples and data.
Comparing Tools: Piezometer vs Monitoring Well vs Observation Well
It’s clear that piezometers, monitoring wells and observation wells all play key roles in groundwater management. Take a look at the table below to compare their key features and uses.
| Function | Piezometers | Monitoring wells | Observation wells |
|---|---|---|---|
| Measuring pore water pressure | Yes | No | No |
| Measuring groundwater level | Yes | Yes | Yes |
| Measuring groundwater flow | Yes | Yes | Yes |
| Collecting samples | No | Yes | Yes |
| Long-term groundwater observation | No | No | Yes |
Each device offers pros and cons that you’ll need to understand before deciding which one is best for your project.
For example, if you’re managing a construction project and need to understand the load-bearing capacity of a site, a piezometer is the right choice.
If you’re concerned with environmental contamination or drinking water quality, opt for a monitoring well.
Or if you need to observe the flow and volume of groundwater over a long period but don’t necessarily need to collect samples, choose an observation well.
You might even need to use both a piezometer and a monitoring or observation well for large-scale or long-term activities.
Choosing the Right Tool for Groundwater Monitoring Needs
When planning your groundwater monitoring project, it’s best to consult with an expert who can understand your unique needs and guide you in choosing the right tool.
Reach out to Precision Drilling Australia for expert advice on groundwater monitoring solutions. We’re one of the leading providers of groundwater monitoring and testing equipment and drilling services in Western Australia and the Northern Territory. With a diverse range of projects under our belt, you can count on us to offer tailored solutions to your requirements.
You can also explore our range of drilling services, testing and equipment installation or learn about previous projects that we’ve worked on.
