Dam body
Displacement of the crest and of the upstream and downstream faces, deformation of the structure, and how both evolve against a reference condition.
We measure displacement of the dam body, the abutments and the slopes around the reservoir remotely, alongside the instrumentation already installed on the structure. Nothing is installed on the dam, the whole dam–reservoir system is read together, and satellite archives can reconstruct how the site behaved in the years before the programme started.
Chosen by infrastructure operators, energy companies, public bodies and engineering firms across Europe
A dam monitoring system is the combination of measurement techniques, acquisition schedule, processing and interpretation used to observe how a dam and its reservoir behave over time — displacement and deformation of the dam body, abutments and foundation, movement of the slopes around the reservoir, and the hydraulic and structural quantities recorded during operation. Its purpose is to make that behaviour measurable and comparable over time, and to give the owner and its engineers the evidence their technical assessments rest on.
Displacement of the crest and of the upstream and downstream faces, deformation of the structure, and how both evolve against a reference condition.
Behaviour of the contact zones and of the founding ground, where the response of the structure is tied directly to the response of the valley side.
Movement of the banks and rim slopes around the impoundment, part of the dam–reservoir system and relevant to how the reservoir is operated.
Wider-area ground deformation, including the slow components that point measurements on the structure alone do not intercept.
The monitored system extends from the structure to its abutments, foundation and reservoir slopes.
Most large dams in Europe and North America were built during the twentieth century and are operated within established dam safety frameworks. Owners and operators already observe and document the behaviour of their structures, supported by appointed engineers and periodic inspection. That existing observation is, in the great majority of cases, based on instrumentation installed on and in the works, read at defined intervals.
Every large dam has its own dam monitoring system, its own reporting duties and its own responsible engineers. NHAZCA does not enter that perimeter and does not change any obligation attached to it. We add a further measurement the owner can use next to the ones already available.
Installed instruments describe the points where they sit, precisely and often continuously. What happens between those points — and above all outside the structure, on the abutments, the rim slopes and the surrounding ground — is largely unobserved.
When a technical question arises today, the available record is the one produced by instruments installed in the past. Where there was no instrument, there is no data — unless it can be reconstructed from a satellite radar archive.
The system that matters is not only the structure: it is the dam, its foundation, its abutments and the slopes that enclose the reservoir. A bank movement can affect the operation of the impoundment without involving the dam body at all. For the landslide phenomenon itself, see our landslide monitoring service.
What we propose replaces nothing that is already installed on the works and does not touch the responsibilities of the owner or of the engineers appointed to the dam. It adds a layer of observation that in-situ instrumentation, by design, cannot cover: a dense areal measurement extending well beyond the dam body, obtained without installing anything on the structure and without access to it.
The starting point is almost always the satellite archive. Before any site visit it is possible to reconstruct how the dam, its abutments and the reservoir slopes behaved in previous years, identify the sectors that show an evolution, and concentrate further investigation there. From that picture we decide what to keep observing from orbit, where a closer and more frequent ground-based measurement is justified, and where dedicated instrumentation should be proposed.
Satellite-derived measurement is available from several providers today, and specialised dam monitoring system products exist. What clients ask us for is the step after the data: acquisition, image-based measurement, in-situ measurement where needed and the engineering reading of the result, delivered by one team that stays accountable for the interpretation.
Reconstruction of the past behaviour of dam, abutments and reservoir slopes from satellite radar series already acquired over the site.
Viewing geometries, acquisition frequency and techniques chosen against the expected movement rates and the questions the owner needs answered.
Continuous acquisition, coverage and coherence checks, and comparison with in-situ readings when the owner shares them.
Maps, time series and technical notes with limits stated, handed to the party that owns the assessment of the structure.
The remote layer complements the existing in-situ system; it does not replace it.
What stays with the owner: the assessment of the structure, the definition of thresholds, the reporting duties and every operational decision. What we bring: one more documented measurement, with its limits stated next to the result.
In a dam monitoring system these techniques are not alternatives to one another. They differ in measurement geometry, density of measurement points, update frequency and sensitivity to site conditions, and they are normally combined. The mix follows the technical question, not a catalogue.
Radar interferometry from orbit measures surface displacement with millimetre sensitivity over wide areas, returning thousands of measurement points instead of a few dozen. On a dam that means observing the body, the abutments, the founding area and the reservoir slopes in the same acquisition, with nothing installed and no access to the works. A multi-year radar archive also allows past behaviour to be reconstructed. Measurement is along the satellite line of sight and update frequency depends on revisit time: viewing geometry and the availability of stable radar targets define what can actually be resolved.
Installed on stable ground facing the sector of interest, terrestrial radar produces continuous displacement maps and time series over a single face at far higher temporal resolution than any satellite. It is the choice when one rim slope sector or one portion of the works requires frequent measurement, with the same line-of-sight and coherence limits that apply to every radar measurement.
NHAZCA proprietary technology. PhotoMonitoring™ measures displacement from repeated images, including images from cameras already installed on site, with no dedicated geotechnical hardware on the works. It supports near-continuous observation independent of satellite passes, at a fraction of the cost of a radar installation. The processing chain separates genuine movement from vegetation, illumination and image-registration effects.
Where the question concerns depth, sliding surface or absolute position, instruments in the ground are required: inclinometers, piezometers, GNSS. We specify them when the measurement objective calls for them. Where the problem is a portfolio of structures rather than a single dam, SGAM combines InSAR and PhotoMonitoring™ into a screening layer that helps decide where detailed investigation is worth funding.
IRIS is the NHAZCA platform for PhotoMonitoring™. It processes the incoming imagery, returns displacement maps and time series for the observed sectors, and makes them available through a browser to everyone who needs them — the owner's technical office, the designer, the site team — without exchanging files.
The interpreted result reaches the decision-maker at the same moment it reaches the analyst, which is usually where conventional monitoring contracts lose days.
The recurring questions asked by dam owners and operators, and the measurement that answers each of them. In practice the techniques are combined.
| What you need to know | Technology | Output | Limit to consider |
|---|---|---|---|
| How the dam body is moving, without intervening on the structure | Satellite InSAR | Measurement points on the structure with displacement time series | Measurement along the line of sight; stable radar targets are required on the surfaces observed |
| How the structure behaved in previous years | Archive InSAR | Multi-year reconstruction of displacement and velocity | Covers the period available in the archive, not earlier years |
| How the slopes around the reservoir are evolving | Satellite InSAR, PhotoMonitoring™ | Velocity maps and active sectors along the reservoir rim | Vegetation and slope geometry affect coverage |
| How a critical sector is moving, at high frequency | Ground-based radar (TInSAR) | Continuous maps and time series over a single face | Requires a stable position with direct visibility of the face |
| How to observe near-continuously at contained cost | PhotoMonitoring™ and the IRIS platform | Displacement from repeated images, consultable in a browser | Depends on illumination, visibility and stability of the camera position |
| Which structures in a portfolio to investigate first | SGAM screening | Portfolio-wide screening and ranking of sectors to investigate | An orienting layer; it does not replace site-specific investigation of a single structure |
| Depth of movement or groundwater conditions | In-situ geotechnical instrumentation | Inclinometer profiles and piezometric readings | Point information: it does not describe behaviour between instruments |
Not sure which combination fits your site? In a short scoping call we identify what is observable remotely in your case, what the satellite archive can say about past years, and how the result can sit next to the measurements you already hold. Ask for a scoping call.
A dam monitoring system does not hand over raw data to be interpreted in-house. We deliver a readable technical picture in which trend, data quality and limits of validity all stay visible.
The spatial distribution of displacement and velocity across the works, the abutments and the reservoir slopes.
How each observed point has evolved, including the archive reconstruction where a usable radar record exists.
Coverage, signal coherence, measurement geometry and the conditions that affect how a result should be read.
The engineering reading of the results, the sectors that deserve attention and the field of validity of the conclusions.
Thresholds, escalation rules and the operational response remain defined and managed by the party responsible for the structure. A dam monitoring system measures and reports; it does not forecast failure. Our contribution is the measurement and its technical interpretation, with the limits stated alongside the result.
Earthfill and rockfill structures, where crest and slope displacement develops over long periods and the observed record matters more than any single survey. Remote measurement adds an areal reading to the instrumentation already installed.
Gravity, buttress and arch structures, where displacement of the faces and behaviour of the abutment contacts are followed over seasonal and multi-year cycles.
Impoundments subject to filling and drawdown cycles, where banks, rim slopes and ancillary works respond to water level and season. Long, consistent series are more informative than isolated campaigns.
Smaller structures, often numerous and spread across a region, where dedicated instrumentation on each is not affordable. Satellite observation provides portfolio-wide coverage from a single acquisition programme.
Banks and valley sides enclosing the impoundment, observed as part of the dam–reservoir system and for their effect on how the works are operated. For the landslide phenomenon in itself, see landslide monitoring.
Spillways, intakes, penstocks and platforms: elements that take part in the operation of the scheme and that an areal measurement intercepts together with the main structure.
This service is part of NHAZCA structural health monitoring services.
The published case studies below concern hydroelectric infrastructure and the slopes around it, not the body of a dam. We present them for what they are: applications of the same method — satellite InSAR, multi-year archive analysis, engineering reading of the results — in contexts adjacent to a dam and its reservoir. Every dam monitoring system still requires its own basis of design.
Public, authoritative sources useful to frame dam surveillance practice and the measurement of ground and structural deformation. They provide technical context and do not endorse NHAZCA.
Dam safety requirements differ between countries, states and reservoir categories. They are referred to here in generic terms with links to official sources; no act, section or date is quoted in this page and none should be added without verification against the primary source.
It is the combination of measurement techniques, acquisition schedule, processing and interpretation used to observe how a dam and its reservoir behave over time: displacement and deformation of the dam body, abutments and foundation, movement of the reservoir slopes, and the hydraulic and structural quantities recorded during operation. NHAZCA delivers it as a service that adds satellite InSAR, ground-based radar and image-based measurement to the instrumentation already installed, together with the engineering interpretation of the results.
No, and the distinction matters. The monitoring arrangement on the works, the reporting duties and the responsibilities of the owner and its appointed engineers stay exactly as they are. Remote measurement is an additional layer: it observes what sits outside the instrumented points, including the abutments and the reservoir slopes, and it provides further evidence supporting the owner's own assessments.
It measures surface displacement with millimetre sensitivity over thousands of points across the dam, the abutments, the founding area and the reservoir slopes, and it can reconstruct past behaviour from archive imagery. It measures along the satellite line of sight, at a frequency set by revisit time, and only where stable radar targets exist: smooth or vegetated surfaces, unfavourable viewing geometry and water bodies limit what can be resolved. It says nothing about what happens below the surface, about pore pressure, or about the internal condition of the structure.
Partly, yes. Satellite radar archives cover several years, and where usable radar targets exist the displacement history over the archived period can be reconstructed even if no dedicated instrument was recording at the time. The reconstruction stops at the beginning of the available archive and its density depends on acquisition geometry and target stability.
No. Monitoring supplies current, quality-controlled measurements of how a structure and its surroundings are evolving, which supports the early identification of sectors that are changing and feeds the thresholds and response procedures operated by the responsible owner and its engineers. It does not produce a deterministic forecast of failure, and any provider claiming otherwise is overselling the measurement.
A spin-off of Sapienza University of Rome: monitoring grounded in applied research and in geological and engineering practice.
PhotoMonitoring™ and the IRIS platform are developed in-house, so the processing chain and its limits are known to the team that signs the report.
Satellite, ground-based radar, image-based measurement and in-situ data converge into a single interpreted reading, instead of separate feeds for your team to reconcile.
Measurement geometry, coverage, coherence and temporal validity stay written in the deliverable rather than disappearing into a slide title.
Tell us about the structure, the reservoir and the technical question you need to answer. We will look at what is observable remotely in your case, what the satellite archive can say about the years already passed, and how the result can sit alongside the measurements you already hold.