How to Choose a Groundwater Three-Water-Level Meter? Understanding the AML913 Integrated Measurement Solution from the Perspective of Data Consistency in Multi-Well Operations
For third-party groundwater monitoring service providers, selecting field equipment is not simply a matter of comparing price and measurement accuracy.
What truly affects the efficiency of multi-well operations is often a seemingly simple yet easily overlooked issue: How can the static water level, well depth, and drawdown data of the same monitoring well be kept as consistent as possible in terms of measurement logic, while reducing deviations caused by equipment replacement and manual operation?
Recently, we received a consultation regarding equipment selection for exactly this type of situation.
The customer is a third-party groundwater monitoring service provider. The customer’s concern was not simply the price of the equipment, but the fact that during multi-well field operations, different equipment often needs to be used separately to measure water level, well depth, and drawdown. Three devices require three separate descents into the well. In addition to increasing on-site operating time, this may also make it difficult to correlate the data because the measurement conditions, calibration status, and manual operating methods of different devices may vary.
In response to this actual scenario, we introduced the AML913 Groundwater Three-Water-Level Meter to the customer.
It adopts an integrated probe design and can complete static water level, drawdown water level, and well depth measurements through a single descent into the well, reducing variables caused by equipment replacement and repeated descents from the perspective of the operating process.
However, it should be noted that: An integrated device cannot replace the retesting and quality control procedures required by groundwater monitoring standards. Its main function is to address the integration of measurement tools, improve field operating efficiency, and reduce some human variables during the data collection process.
The following explains this issue from three perspectives: field operating procedures, standard requirements, and actual equipment selection.
I. Why Can Separate Measurements with Multiple Devices Easily Lead to Data Correlation Problems?
One Afternoon, Three Wells, and Multiple Descents May Be Required
In a traditional groundwater monitoring field operation, different devices may be required separately to complete:
- Static water level measurement;
- Well depth measurement;
- Monitoring water level changes during well development.
If a water level meter, well depth meter, and drawdown monitoring device are used separately for these three tasks, field personnel need to carry multiple sets of equipment and repeatedly replace probes, cables, and instruments according to different measurement tasks.
What actually increases the risk is not just the operating time.
For the same well, if the static water level, well depth, and drawdown data come from different devices and different descents into the well, field personnel need to ensure that the measurement position, operating method, and recording method remain consistent each time.
The customer’s actual concern at the time was:
“The data may not correspond because of measurement errors caused by human operation.”
This concern has a practical basis.
Taking HJ 164-2020, Technical Specification for Environmental Monitoring of Groundwater, as an example, when manual methods are used to measure groundwater levels, the difference between two consecutive static water level measurements is required to be within ±1 cm/10 m; otherwise, the measurement needs to be repeated. The standard also specifies that, where conditions permit, automatic water level meters, electric water level meters, or groundwater multiparameter automatic monitoring instruments may be used for water level measurement.
In other words, the standards focus not only on “whether the measurement has been conducted,” but also on whether the measurement results meet quality control requirements.
Therefore, reducing unnecessary equipment switching and repeated descents into the well can reduce field operating variables, but it cannot eliminate the measurement and verification procedures required by the standards.
II. Why Does Groundwater Monitoring Need to Pay Attention to Water Level, Well Depth, and Drawdown at the Same Time?
In actual projects, the static water level often receives the most attention, but well depth and water level changes during well development also have practical significance.
| Data | Main Function | Field Significance |
|---|---|---|
| Static water level | Establish the reference for groundwater level measurement | Used to determine the current water level status of the monitoring well and serve as a reference for subsequent measurements |
| Well depth | Determine basic information such as the actual water-containing space inside the well | Can be used for relevant well-volume calculations and monitoring well operation and maintenance |
| Drawdown water level | Reflect water level changes during pumping and well development | Used to control water level decline during low-flow well development and avoid excessive pumping |
HJ 164-2020 clearly requires groundwater water levels and well water depth to generally be measured before groundwater quality sampling, and provides the relevant calculation relationship for well water depth. For water level measurement, the manual method requires consecutive measurements and error control.
For the long-term operation and maintenance of groundwater monitoring wells, DZ/T 0307-2023, Specification for Operation and Maintenance of Groundwater Monitoring Network, is a current industry standard used to regulate the operation and maintenance of groundwater monitoring networks.
Why Should Well Depth Not Be Ignored?
Well depth may not appear as intuitive as water level, but it affects calculations related to the volume of water inside the well.
During groundwater sampling and well development, relevant technical requirements involve the water volume inside the well and the stability of field water quality parameters. HJ 164-2020 specifies that well development is required before sampling, and that the stability of field parameters such as turbidity, pH, and electrical conductivity, as well as the amount of water pumped out during well development, should be used as one of the bases for assessment.
Therefore, if the well depth data has significant deviations, subsequent assessments involving the water volume inside the well may also be affected.
For long-term operating groundwater monitoring wells, some local authorities have further specified the frequency of well depth maintenance measurements in accordance with requirements such as HJ 164-2020. For example, the groundwater monitoring well management requirements issued by the Shanghai Municipal Bureau of Ecology and Environment clearly specify that the well depth of monitoring wells should be measured once a year.
Why Does Drawdown Need Continuous Attention?
One of the core principles of low-flow well development is to avoid excessive disturbance to the groundwater conditions inside the well during pumping.
Taking HJ 1019-2019, Technical Guidelines for Sampling of Volatile Organic Compounds in Soil and Groundwater at Contaminated Sites, as an example, when a bladder pump or low-flow submersible pump is used for well development, the groundwater level should be measured and the water level decline should be kept below 10 cm. If it exceeds 10 cm, the well development flow rate should be appropriately reduced.
Therefore, drawdown is not data that can simply be measured afterward; it is a dynamic monitoring item during the well development process.
III. What Split-Type Equipment Actually Adds Is Not Just Field Operating Time
If three separate devices are required to measure one well, three types of variables will be added to the field operation.
1. Operating Costs Caused by Repeated Descents into the Well
Three devices usually mean multiple sets of cables, probes, and instruments.
Every time the equipment is changed, the equipment status, measurement position, and recorded readings need to be reconfirmed. The more wells there are, the more obvious the repeated operations become.
For third-party groundwater monitoring service providers, if multiple wells need to be continuously completed in the field in a single day, such repeated operations can further amplify the issue.
2. Differences in Measurement Conditions Caused by Different Devices
Different instruments may use different measurement structures, probes, and reading methods.
For the current project selection, a more appropriate approach is:
Make a comprehensive judgment based on the actual groundwater monitoring standards adopted by the project, instrument technical specifications, verification/calibration status, and field quality control requirements, rather than simply comparing the accuracy level in a particular historical standard.
This can both avoid outdated references to standards and better reflect actual engineering equipment selection.
3. Variables Created by Personnel Operation
This is the layer most easily overlooked in field operations.
For example, static water level measurement requires retesting, while unified measurement projects may also have specific requirements for retesting and measuring rope verification; during well development, changes in water level also need to be continuously observed.
As the number of monitoring wells increases, personnel need to repeatedly perform the same actions.
Therefore, one practical goal of equipment selection is:
Without changing the requirements of the applicable standards, minimize unnecessary equipment switching and manual judgment steps as much as possible.
IV. AML913 Groundwater Three-Water-Level Meter: Three Measurements Completed Through One Descent into the Well
In response to the above field requirements, the AML913 Groundwater Three-Water-Level Meter adopts an integrated probe design.
The core concept is not simply to “put three devices together,” but to complete multiple measurements in the same well through a single probe.
One descent into the well can complete:
- Static water level measurement;
- Drawdown water level measurement;
- Well depth measurement.
Main AML913 Parameters
| Item | AML913 Product Parameters |
|---|---|
| Measurement method | Integrated probe, completing static water level, drawdown water level, and well depth measurements through one descent into the well |
| Measurement depth | Standard 100 m; 200 m, 300 m, and other lengths can be customized |
| Resolution | 1 mm |
| Probe diameter | 2.9 cm |
| Water detection indication | Provides audible and visual indications when reaching the water surface |
| Bottom contact indication | Provides audible and visual indications when reaching the bottom of the well |
| Linkage function | Can be used with a bladder pump controller or sampling pump controller to achieve drawdown linkage |
From the perspective of field use, this design mainly addresses three practical issues.
One Descent into the Well: Reduce Equipment Switching
Tasks that previously required separate measurements can be completed through the same probe, thereby reducing the number of repeated descents into the well.
For multi-well monitoring projects, this change is particularly applicable to field operations that require continuous completion of water level, well depth, and well development process monitoring.
Audible and Visual Indications: Reduce the Pressure of Manual Judgment
Audible and visual indications when the probe reaches the water surface or well bottom can help field personnel confirm measurement points.
It cannot eliminate human operation, but it can reduce the uncertainty caused by relying solely on tactile feedback, experience, or visual judgment.
Drawdown Linkage: Link Water Level Control with Pumping Equipment
AML913 can be used together with a bladder pump controller or sampling pump controller to achieve drawdown linkage.
When the specific configuration and project control logic meet the requirements, water level monitoring can be connected with pumping control so that the equipment can perform actions such as stopping the pump or resuming sampling according to preset conditions.
It should be emphasized that the actual linkage logic should be determined according to the field equipment configuration, controller functions, and project technical requirements. It should not be simply understood that personnel monitoring is no longer required once the equipment performs automatic actions.
V. What Types of Monitoring Wells Are Suitable for a 2.9 cm Probe?
The AML913 probe has a diameter of 2.9 cm.
Conventional environmental groundwater monitoring wells generally need to meet corresponding well casing diameter requirements. For example, the relevant monitoring well construction requirements in HJ 164-2020 generally require the inner diameter of the monitoring well casing to be no less than 50 mm to meet requirements for well development and water collection; local management documents also contain clear references.
Therefore, in conventional monitoring well applications, the 2.9 cm probe size provides a certain installation space advantage.
However, actual projects still need to confirm the following before use:
- Inner diameter of the monitoring well;
- Whether other equipment is present inside the well;
- Whether the well casing is deformed;
- Whether there is sediment inside the well;
- Whether the probe can smoothly reach the target depth.
It cannot be determined solely from the probe diameter that all monitoring wells can be directly used with it.
VI. How Should the Measurement Depth Be Selected? Is 100 m Enough?
The standard AML913 measurement depth is 100 m.
If the project involves deeper monitoring wells, different lengths such as 200 m and 300 m can be customized according to the actual well depth.
One easily overlooked issue here is:
Measurement depth is not only about whether the probe can reach the bottom of the well; cable length, available depth margin, field operating space, and the actual measurement method must also be considered at the same time.
Therefore, if the project includes monitoring wells deeper than 100 m, it is recommended to confirm the actual well depth in advance during the procurement or customization stage and specify the cable specifications, rather than directly ordering the standard 100 m model.
VII. What Problems Can AML913 Solve, and What Problems Can It Not Solve?
To avoid misunderstandings during equipment selection, product capabilities and standard requirements can be viewed separately.
Problems AML913 Can Solve
- Reduce equipment switching between water level, well depth, and drawdown measurements;
- Complete three measurements through one descent into the well using an integrated probe;
- Assist in confirming water detection and bottom contact status through audible and visual indications;
- Reduce repeated operations caused by separate descents of multiple devices;
- Work with relevant pump controllers to achieve drawdown linkage;
- Provide a certain degree of process simplification for continuous multi-well field operations.
Problems AML913 Cannot Replace
- It cannot replace the static water level retesting required by applicable standards;
- It cannot replace routine inspection and calibration management of measurement equipment;
- It cannot replace the well development process before groundwater sampling;
- It cannot replace the measurement of field water quality parameters such as pH, electrical conductivity, temperature, dissolved oxygen, oxidation-reduction potential, and turbidity;
- It cannot assume that all monitoring wells are within 100 m;
- It cannot replace the project’s own data quality control system.
This is also why, during this equipment selection discussion, we did not describe AML913 as “one device that solves all groundwater monitoring problems.”
Its more accurate positioning is:
For groundwater field operations that require simultaneous acquisition of water level, well depth, and drawdown data, the integrated probe reduces repeated descents into the well and equipment switching, thereby optimizing the measurement process.
VIII. The Final Focus of This Equipment Selection Consultation Was “Fit,” Rather Than a Single Parameter
The actual problem that needed to be addressed in this customer consultation was not “whether there is an instrument with higher accuracy.”
The customer was facing a complete field process:
Multiple monitoring wells → Multiple measurements → Multiple devices → Multiple descents into wells → Increased manual operations → Difficulty correlating data.
Therefore, equipment selection should also start from the complete process.
If the field operation requires static water level, well depth, and drawdown data at the same time, the value of an integrated device lies in reducing switching between measurement procedures.
If the project only requires simple water level measurement, or if the monitoring well depth, diameter, and field conditions are not suitable for an integrated probe, the corresponding equipment should still be selected according to specific requirements.
This is also the principle we adhered to during this discussion:
First clarify the standard requirements and field problems, then determine whether the equipment is suitable, rather than changing the project requirements in order to recommend the equipment.
AML913 Groundwater Three-Water-Level Meter FAQ
1. What is a groundwater three-water-level meter?
A groundwater three-water-level meter is a device that integrates multiple groundwater measurement functions into a single probe. AML913 can complete static water level, drawdown water level, and well depth measurements through one descent into the well, making it suitable for groundwater monitoring sites that need to obtain all three types of data.
2. Can AML913 really measure three sets of data through one descent into the well?
Yes. According to the product design, AML913 adopts an integrated probe that can complete static water level, drawdown water level, and well depth measurements during a single descent into the well.
However, the measurement timing and field operating procedures corresponding to different types of data may vary. Actual use should still follow the project’s technical plan and relevant standards.
3. After using the three-water-level meter, is it still necessary to measure the static water level twice?
If the standard applicable to the project requires static water level retesting, it is still necessary.
The integrated device reduces equipment switching and repeated descents into the well; it does not automatically eliminate the retesting procedures required by the standards. HJ 164-2020 specifies error requirements for two consecutive measurements of manually measured water levels.
4. Why is well depth measurement important for groundwater monitoring?
Well depth is important basic data for determining the actual condition of the monitoring well and related information about the water inside the well. When calculations involving the volume of water inside the well are required, well depth data directly affects the calculation results.
Therefore, well depth is not auxiliary data that can remain unchanged for a long period of time.
5. Why should drawdown be monitored during well development?
Because pumping causes the water level in the monitoring well to change. If the water level drops too quickly or exceeds the control range specified by the project, it may affect the low-flow well development and groundwater sampling process.
HJ 1019-2019 specifies water level decline control requirements for low-flow well development. For example, when a bladder pump or low-flow submersible pump is used, the groundwater level should be monitored and the water level decline should be kept below 10 cm; if it exceeds this value, the well development flow rate should be reduced.
6. Can AML913 replace a multiparameter water quality meter?
No.
AML913 mainly addresses water level, drawdown, and well depth measurement. Parameters such as pH, electrical conductivity, temperature, dissolved oxygen, oxidation-reduction potential, and turbidity involved in groundwater sampling still require corresponding field water quality measurement equipment. HJ 164-2020 also contains relevant requirements for well development before sampling and the stability of field parameters.
7. What is the standard measurement depth of AML913?
The standard measurement depth is 100 m.
If the monitoring well depth exceeds 100 m, 200 m, 300 m, and other specifications can be customized according to actual requirements during procurement, and the cable length and configuration should be confirmed in advance.
8. What types of wells is the 2.9 cm probe suitable for?
The AML913 probe has a diameter of 2.9 cm. For conventional monitoring wells, suitability can be assessed according to the inner diameter of the well casing and actual conditions inside the well.
Before use, it is still recommended to confirm the inner diameter of the well casing, obstacles inside the well, sediment, and actual descent depth. Applicability cannot be determined solely based on the probe diameter.
9. What is the greatest practical value of an integrated groundwater measurement device?
For organizations that need to continuously conduct field operations across multiple wells, the core value is not simply “carrying two fewer devices,” but rather incorporating water level, well depth, and drawdown measurements into the same measurement process as much as possible, reducing operating variables caused by equipment replacement and repeated descents into the well.
10. Is AML913 suitable for all groundwater monitoring projects?
Not necessarily.
If a project only requires a single water level measurement, or if the monitoring well depth, diameter, and field conditions are not suitable for an integrated probe, equipment should be selected according to actual requirements.
If a project needs to obtain static water level, well depth, and drawdown data simultaneously and wishes to reduce repeated descents into the well and equipment switching, an integrated three-water-level meter solution can be evaluated as a key option.
The selection of groundwater monitoring equipment ultimately needs to return to the field operation itself.
If a well requires separate measurements of static water level, well depth, and drawdown, three devices and three descents into the well do not merely increase the workload; they also increase the variables among equipment status, operating procedures, and manual judgment.
The AML913 Groundwater Three-Water-Level Meter adopts an integrated probe and completes static water level, drawdown water level, and well depth measurements through one descent into the well, providing an equipment solution that reduces repeated operations for multi-well groundwater monitoring.
However, equipment integration does not mean that standard procedures can be skipped.
A more reasonable equipment selection logic should be: first clarify the project standards and field requirements, then determine which operating procedures can be reduced by an integrated device and which quality control steps must still be retained.
For third-party groundwater monitoring service providers, this approach to equipment selection is closer to actual field requirements than simply comparing prices or individual accuracy parameters.
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