Dam monitoring provides early warnings of structural issues, helping operators and owners manage risks and meet regulatory standards. While monitoring technology has advanced considerably, truly effective outcomes depend on how well dam monitoring systems are designed, installed, configured, operated, and maintained.
As providers of high-precision monitoring systems for dams, Leica Geosystems, part of Hexagon, has supported dam owners and operators worldwide, providing the technology they need to ensure structural health and safety, from robotic total stations and GNSS sensors to the software that automates measurements and brings the data together.
Here, we highlight three frequent pitfalls in dam monitoring and how to overcome them.
Understanding and configuring the data
The most common problem we see in dam monitoring systems is incorrect use of technology.
For example, we recently saw a case where a total station installed to measure the movement of a dam was also moving with the structure, without any stable external reference points. This meant the operators couldn’t distinguish between the movement of the instrument and the movement of the dam by looking at the data, making it less relevant for deformation analysis.
Yet, even with a perfectly installed system, the biggest risk is that the data is not actively reviewed by experienced personnel. A monitoring system will be ineffective if data is either not reviewed or poorly analysed.
Tailoring the solution to both the site conditions and primary stakeholders is one solution. By using one integrated system, for example an automated system of geotechnical sensors and GNSS, operators can receive a real-time structural health check on critical assets. A central software platform integrates, analyses, and visualises the data from these varied sources into a single, understandable interface.
Smart integrated systems can send alerts when movements exceed certain thresholds, keeping stakeholders up to date with the information they need to act swiftly. As required, expert land surveyors can then provide periodic surveys using a total station to gather more detailed spatial data across the wider structure. This hybrid approach allows for a comprehensive, cost-effective, and risk-appropriate monitoring plan.
Outdated technology
Another common issue is outdated technology. Many dams still rely on systems installed decades ago, which are often only replaced after disasters or when enforced by new legislation.
For example, one dam we visited recently had been relying on monitoring equipment installed in the 1970s. Parts kept failing as time went on, and for the last 15 years, the installed system has become ineffectual. The introduction of new legislation – due to increased risk of natural disasters and heavy rainfall in the region – meant the dam operators were obliged to update their monitoring solution as a matter of public safety.
While outdated or poorly maintained technology can result in incomplete data, modern systems capture comprehensive data to give the full picture of the dam’s behaviour over time. Fully automated and permanent installations provide continuous data without human intervention, an often-necessary approach for high-risk or remote sites.
Robotic total stations, a key technology in such systems, automatically measure prisms installed on the dam, delivering high-accuracy 3D coordinates to track surface displacements. Additionally, GNSS technology offers absolute 3D position data, which is vital for monitoring remote assets or confirming the stability of any reference network used.
A wide array of geotechnical sensors is typically integrated to understand the structural health of the dam and adjacent assets. These include piezometers to measure water pressure, tiltmeters for rotation, strain gauges for load and stress, and crack gauges for expansion and contraction. Many can be deployed as part of a wireless mesh network, simplifying installation. To ensure reliability, these systems can use solar power with battery backup should the direct supply fail.
The East Bay Municipal Utility District (EBMUD) in California demonstrates the benefit of a modern system. After severe storms, EBMUD installed one of the nation’s most advanced automated GNSS systems at its Pardee and Camanche reservoirs. The monitoring solution reports crest elevations remotely, helping EBMUD reduce the time needed for surveys.
Its value was proven when, after a 4.4 magnitude earthquake, engineers were able to log in to the system remotely and immediately confirm that there had been no significant movement on the dam. Moreover, the automated system helps them meet state monitoring requirements since it can be more easily tied into state-wide emergency and seismic monitoring systems.
Staff & resource optimisation
A significant challenge for dam owners is the need for high-quality monitoring data, which often requires advanced skills, substantial resources, and careful planning. With limited access to large teams for frequent manual surveys – particularly at remote locations – automation has become an essential solution to ensure dams remain safe and compliant. These challenges arise from a combination of factors, including resource constraints, specialised expertise, and the inherent risks involved, rather than shortcomings on the part of dam operators.
One example of this is Enel Green Power, a multinational renewable energy company. Four of their hydroelectric plants in Italy and Spain were struggling with scheduling and availability to obtain manual deformation measurements, leading to a lack of continuity. So, they installed an automated GNSS monitoring system, which now provides continuous, 24/7 data on the structural health of the dams, eliminating the need for costly and time-consuming long-distance travel for manual checks.
It allowed them to correlate geodetic data with geotechnical sensors, creating a more detailed and complete description of any deformation. Importantly, the new system provides data about the infrastructure’s condition all the time, not just when survey crews are available.
Learning from the data
Monitoring systems, however, provide data that does more than mitigate risks – they can also shape the future of dam construction. Automated systems provide rich datasets that can validate the original design assumptions or highlight areas where future designs could be improved, saving long-term costs and increasing safety.
This is because the large amount of data collected by automated systems allows engineers to understand the true, dynamic behaviour of a dam under various real-world loads. Viewing monitoring as a design validation tool facilitates safer, more efficient, and more resilient dams.
Ultimately, effective monitoring enables operators and regulators to dynamically understand and manage risk, keep dams safe, and ensure regulatory compliance.
