From bees to basalt, hexagons appear throughout our natural world. Humans have been using them for hundreds of years to build stronger structures, to create order, and even to track vehicles. Rezatec’s Dam Monitoring solution uses hexagons to help direct dam operators to the areas of each dam and reservoir that need attention. It allows clients to get insights over the entire area of interest, not just the crest of the dam.
Hexagons have many redeeming features that make it useful in both nature and engineering. Its ability to tesselate is useful for mapping purposes, it can also represent curves in a dam more naturally than square grids. Hexagons can be organised hierarchically to allow smaller hexagons to be nested within a larger size, allowing data to be summarised. Rezatec’s Dam Monitoring uses two sizes to give more detail where required.
Dam owners need a quick and efficient way to monitor and locate any potential issues on their dam and the surrounding reservoir. New technologies are entering the market offering more data to help monitor these often large and remote dams. But how easy is it to interpret the information they provide? Every dam is different in terms of construction, surrounding terrain and environment as well as the geology and climatic factors for its location. Rezatec’s Dam Monitoring product assesses large amounts of data from satellites over time. Ground motion is monitored as an indicator of subsidence or uplift and vegetation is monitored as a proxy for seepage or piping. So many data points though need a further layer of analysis to make a confident insight for the dam operator, which is where the hexagons come into play.
Initial retrospective analysis uses 3 years of historic satellite data to create a signature baseline of movement or vegetation vigor and moisture for each hexagon across the entire dam. Using this baseline of ‘normal’ behaviour, it can identify statistical anomalies, that are observations that fall outside of the normal trend. Seasonal differences are accounted for, and some may find it surprising that one part of a dam may experience several millimetres difference in movement each season as normal, while a nearby section has much less. An observation of 0.5mm subsidence may be normal monthly seasonal change in one section of the dam but way off normal in another. The hexagons offer a more granular analysis of the dam to make it easier to distinguish an area that is worth a second look.
A good reason to utilize technology and data driven decision-making is to remove unnecessary visits to site, which are costly and for some remote or inaccessible dams, are a health and safety hazard. In-situ technologies usually still need fitting and maintenance. As satellites circle the earth collecting data, Rezatec’s Dam Monitoring solution can take in this new data and provide regular updates that helps remotely monitor changes at the dam. The analysis can be sorted or filtered and compared with the longer-term data to give context to the anomalous readings. This can help triage the dam before deciding whether to send anyone to site. It can also focus any site visits to very specific locations on the dam making those visits more productive. This can help both increase monitoring where site visits are difficult, such as for Hunter Water in Australia who needed to close a major road everything they surveyed their Grahamstown dam; to a client that wanted to reduce their monthly dam visits to quarterly while maintaining their duty of care and robust monitoring program.
One of the attributes that make hexagons a well-used shape in nature and engineering are their strength. While these hexagons are not bearing any weight, they can make your dam monitoring program stronger and more effective. Proactively managing the risk that your dam presents is not only the responsible thing to do but makes business sense when you consider insurance, regulatory requirements and continuation of your licence to operate.