Groundwater is the water below the earth’s surface, held in or moving through layers of soil, sediment, or rock. It maintains wetlands and river flow and supports biodiversity. It is also a source for municipal water supplies, private water supplies, and crop irrigation.
Groundwater is an invaluable resource that communities must manage. But it is hard to control what isn’t measured, and groundwater is one of those elusive things that is hard to measure. Today private well owners, farmers, businesses, and communities use complicated and expensive methods to determine groundwater levels. As a result, the resource is under measured.
A new technology that uses sensors and communication gateways eliminates this problem by providing actionable data to plan for and manage the groundwater supply. This white paper explores the advantages of this technology.
Market Drivers Impacting Actionable Information and Analytical Tools
Managing water is a significant problem and has become one of humanity’s foremost priorities. According to A.J. Jakeman of Australian National University, current replenishment rates of groundwater cannot match the rates of depletion in many parts of the world. And the declining quality of the remaining groundwater is not supporting agricultural, industrial, and urban demands and ecosystem functioning, especially in the developed world. In the developing world, the amount and quality of groundwater often fail to meet essential human needs.
It’s essential to have a spatially distributed, long-term monitoring well network for sustainable groundwater resource management, and communities play a crucial role. As reported by Kathleen E. Little of University of Calgary, community-based monitoring involving citizen scientists provides a complement to existing government-run monitoring programs.
However, communities usually manage and understand well surface water resources but not the groundwater resources, which are often hidden and more complex to conceptualize.
For instance, as a rule, communities don’t know if groundwater levels diminish because of overuse or if they become contaminated because of unregulated extraction. According to business expert Caro Bouwhuis, municipalities need to track the systems that pump water into aquifers for “refilling” them. Communities should avoid scenarios where an aquifer is too empty or too full. So it is vital to be able to track the level of the water table and to “see” changes in the water level over a wide area and a long time.
Therefore, the emergence of new tools that integrate, manage, and share large data sets is critical to the success of community-based monitoring and makes it possible for the field of continuous monitoring to move forward.
In other words, new technologies must make it possible for communities to treat groundwater like a bank account: ensuring that deposits cover withdrawals.
The Challenges of Poor Groundwater Data Gathering
Currently, there are three conventional ways to get information about the water level in a well: wetted steel tapes, pressure transducers, and sonic well sounders.
Wetted Steel Tapes
Users can measure the depth of water by lowering a wetted steel tape into the well until the lower part of the tape is underwater. A chalk coating on the last few feet of the tape indicates the exact water level. When users remove the tape from the well, they can read the depth of the water from the dry length of the tape.
Pros. The wetted steel tape is an accurate method for measuring water levels in non-flowing wells. Because of the small tape diameter, users may access wells with small entry ports. The tape causes little interference with pump wiring.
Cons. Oil, ice, and debris may interfere with a water-level measurement. Likewise, corrections to the measurements are necessary if the well casing is angled. When measuring water levels that are greater than 500 feet, tapes may expand and stretch, which may need some correction or change to the measurement. Finally, in hot or dry conditions, especially in deep wells, the wetted chalk mark can dry before the tape is retrieved from the well.
Pressure transducers are submersible sensors that measure the pressure of the column of water above them in the well and send information to above-ground data loggers. They record water levels.
Pros. Easy to install, maintain, and calibrate. The output can be analog or digital, depending on the transducer model.
Cons. The most frequent problems are related to open and short circuits. But failures often occur because of water leaking into the housing, grounding problems, voltage surges, diaphragm failures, power-supply failures, faulty shielding, and over-range problems.
Sonic Well Sounders
This tool uses soundwaves to measure the depth to the water level by bouncing sound waves off the water’s surface. Sonic well sounders are simple to use and provide instant data.
Pros. The meter can be used to measure water levels in monitoring wells and production wells. Because it doesn’t touch the water and there are no probes or wires to hang up, there is no risk of contaminating the well.
Cons. The meter’s accuracy decreases with well diameter. Obstructions in the well casing can cause erroneous readings.
Sources: United States Geological Survey (USGS); Department of Health, Washington State; and Department of Water Resources, California State.
The Solution: Use of Remote Telemetry
Recently a remote telemetry unit has been introduced to make measuring groundwater easier and more cost-efficient. To understand how the tool works, it’s important to understand two terms:
Telemetry: The automatic measurement and transmission of data from remote or inaccessible locations.
Remote monitoring: A process by which the user makes automatic measurements remotely. Data may be transmitted via a telemetry system but could also be stored electronically and collected manually at the data-gathering location.
So a remote telemetry unit is a sensor, a communication gateway, and a collection of information about groundwater from one or more sensors or any other related sources. The data is available securely to customers anywhere, via website, email, text messages, and smartphones.
How it Works
Unlike acoustic sonar, which is analog, a remote telemetry unit sends a programmable digital signal into the well. The digital signal captures details about the well and the groundwater, including:
- The water level while both pumping and at rest
- The infrastructure to hold pumps and move water
- The noises that the well makes, like the hum of a pump or leaks in the water or casing pipes
- The surface of the casing pipe or borehole
- Changes in the well, like when screens are exposed because of declining levels or when water begins to cascade in the well
- To gather data from sensors, a remote telemetry unit includes a secure communications gateway that talks with the sensor via radio and then sends data to the cloud via ethernet.
The gateway can be positioned up to a half-mile away and can receive data from many sensors. A website displays the information in real-time; in this way, the customers can see what’s happening in the well. They can also set alerts and receive messages if they don’t want to visit the website.
Many significant benefits emerge when communities create a groundwater monitoring network using remote telemetry, including:
- Makes data collection more agile and frees up time for the vital work of analysis and scenario planning
- Empowers communities to take smart action; they can access accurate and rich data sets, analyze them, and create a report
- Increases data collection when compared with collecting data manually
- Improves the monitoring of where the water stress areas are
- Expands coverage and simplifies measurement
- Diminishes data-collection errors
- Increases quality, quantity, and uses of data
- Decreases costs and expenses
- Enhances diagnoses and troubleshoots problems
- Reduces travel and the associated risks to workers
- Allows continuous timed water-level analysis without touching the water, making it easier to analyze pumping impacts and seasonal recovery
What to Look for in a Remote Telemetry Provider
When seeking a company to aid in gathering information about groundwater, many factors should be considered. The provider should
Incorporate programmable digital signals. Select a provider that offers a digital sensor instead of acoustic sonar (which is analog). When a programmable digital signal enters the well, it creates an image of the well’s characteristics and the groundwater.
Understand performance and architecture groundwater. A good provider will use a sensor that knows if it has made a mistake and will recalibrate automatically while continuously verifying accuracy.
Use sensors that don’t calculate or store data at the well. A competent provider must include this critical security aspect so the sensor will be almost always empty, and the data will be useless out of context.
Offer privacy. Work with a company that transmits only raw encrypted numbers, which is useless without the infrastructure on the cloud. More importantly, the information about a well, or the water in it, should be calculated only when customers log into the network and request the information.
Deliver continuous water level and well operations measurements. Be sure the provider allows its clients to see exactly how often and how long water is pumped during the day or week. That enables the client to keep tabs on groundwater levels relative to the height of the pump in the well. They can also see if the well is recovering as it should or more slowly than before, and they can compare data between different years. They can also set up their account to call their well servicer automatically when there is a possible problem.
Wellntel, a Groundwater Sensor Technology and Data Science Company
Wellntel delivers actionable information and analytical tools to inform the sustainable management of groundwater.
Find more information at www.wellntel.com.
If you are ready to move water monitoring into the future, call Wellntel at 1-844–935–5426 to start planning your network.