Level Measurement & Control


Level monitoring of groundwater

October 2019 Level Measurement & Control

Much of our drinking water is extracted from subterranean resources. Water that falls to the surface of the Earth drains not only into rivers and lakes, much of it will permeate into subterranean reservoirs. These aquifers are natural underground reservoirs that store groundwater.

Level monitoring of groundwater is critical to understand what is happening to the subterranean water and to allow any exploitation of this resource. Therefore, narrow boreholes are sunk into the soil that allows the groundwater level and quality to be monitored.

These wells will usually include a level monitoring system to keep track of how deep wells and water extraction are affecting the overall groundwater level.

If the soil is composed of permeable sand and rock then as the water is extracted from deep bore wells, the overall water level of the area will be drawn down, as the resource water can easily flow from all separated reservoirs into the deep bore well. Also, if water permeates the soil e.g. due to rain, the underground reservoir is quickly restored and the water level increases rapidly, as the water can pass quickly through the permeable soil.

However, if the water is held in a barely permeable e.g. clay-like soil, then the water resource is stored in many small pockets. When water is then extracted from deep bore wells, the level monitoring of groundwater at the well will show a fast drop in water level and it will take a considerably longer time to replenish from the surrounding area. Also the surrounding monitoring well levels will not change as rapidly as the water resource takes more time to pass through to the deep well.

Contamination must be prevented

Monitoring wells are also used for water quality monitoring, to ensure that pollution is not getting into the subterranean water supply. For example, this may be critical around landfill sites where changes in the water level, e.g. due to an overflow, could allow contaminated water to escape into pure groundwater reservoirs. Both the level monitoring of groundwater and the monitoring of the stored contaminated water form a critical balance. Monitoring systems therefore usually combine level and water quality sensors to detect any contamination.

It is estimated that only 3% of the total water resources on Earth are consumable fresh water, of which less than one-third is easily accessible, for the most part stored as groundwater. Therefore, it is essential to use reliable solutions for level monitoring of groundwater, to preserve these reservoirs and to exploit these resources sustainably.

Groundwater level can be measured using submersible pressure transmitters such as the WIKA LF-1, a transmitter with low power signals and increased life service through the fast response times and a low current consumption.

An ideal transmitter must be suitable for long periods of submersion in stagnant and flowing water. Excellent sealing, special cabling, anti-clogging and overvoltage protection during lighning strikes must also be considered to achieve exceptional protection against failure.


Credit(s)



Share this article:
Share via emailShare via LinkedInPrint this page

Further reading:

Check valve with redundant sealing
September 2020, WIKA Instruments , Valves, Actuators & Pump Control
The new model CV check valve from WIKA is designed for a wide range of applications in the process industry. Its sealing system reliably prevents backflow of liquid and gaseous media.

Read more...
Clip-on indicator with Bluetooth and logging
September 2020, WIKA Instruments , Data Acquisition & Telemetry
Monitor live process values and diagnostic information on any iOS/Android device running the free PPS application, or monitor directly on the display.

Read more...
Level switch with float
September 2020, Instrotech , Level Measurement & Control
Instrotech now offers Kobold’s M-series level switch comprising a float that slides up and down with the liquid, along a guide tube. Thus, up to four reed contacts moulded in the guide tube are switched ...

Read more...
New dimensions in versatile level measurement
August 2020 , Level Measurement & Control
AFRISO presents a new generation of devices based on capacitance and ultrasound, as well as on the guided micropulse measuring principle.

Read more...
Level switch with float
August 2020, Instrotech , Level Measurement & Control
Instrotech now offers Kobold’s M-series level switch comprising a float that slides up and down with the liquid, along a guide tube. Thus, up to 4 reed contacts moulded in the guide tube are switched ...

Read more...
Dry bulk level sensor
August 2020, DRH Components , Level Measurement & Control
The Roto-Bin-Dicator Pro is a paddlewheel type level device that outperforms others in its class. The fail-safe model is unique in that it comes standard with functional diagnostics that detect a unit ...

Read more...
Combination of digital pressure gauge and smartphone via Bluetooth
August 2020, WIKA Instruments , Pressure Measurement & Control
For optimal process efficiency in pharmaceutical applications, solutions featuring wireless communication are becoming first choice, especially in mobile applications.

Read more...
Only the best for man’s best friend
August 2020, VEGA Controls SA , Level Measurement & Control
Vegapuls 69 reliably measures the level in small dosing vessels

Read more...
Upgrade for PSM-700 pressure switch
May 2020, WIKA Instruments , Pressure Measurement & Control
WIKA’s PSM-700 pressure switch with large adjustable switch differential is now able to withstand higher process temperatures. Previously, the process media was limited to a temperature range of -30...

Read more...
Upgrade for PSM-700 pressure switch
June 2020, WIKA Instruments , Pressure Measurement & Control
WIKA’s PSM-700 pressure switch with large adjustable switch differential is now able to withstand higher process temperatures. Previously, the process media was limited to a temperature range of -30ºC ...

Read more...