Since 2017, drones have been prohibited from flying within 300-400 feet of critical national infrastructure.  Of the 12 facilities on the national drone “no-fly” list, 8 are hydroelectric dams.  Their importance to the survival of surrounding communities is deemed so vital that no commercial or recreational drone is allowed to fly near them.

But that doesn’t mean drones have no connection to dams.  In fact, drones, under proper government control, can play a vital role ensuring that these massive concrete structures are being properly maintained.  Thanks to drones, a comprehensive detection of cracks, fractures, leaks and other potential structural problems – especially those developing in remote difficult-to-access areas – can occur before a full-scale catastrophe occurs.

Southern California Edison (SCE) is just one of the nation’s important dam systems that is deploying drones to great advantage, especially during snowy winter months when road access is limited and on-site inspections by human surveyors are especially challenging.  Drones can be equipped with thermal sensors and LiDAR-enhanced camera surveillance to detect conditions invisible to the naked eye.   The drones also stitch together camera images to create a 3D photogrammetric model of the dam and its environment to anticipate how problems might evolve over time.

By substituting drone pilots for human inspectors, SCE can conduct inspections of its statewide dam system – a total of 83 dams, running from Catalina Island in the south to Fresno in the north – more quickly and more thoroughly, and also more safely.  Conventional field inspections require specialized equipment and training and are time-consuming to perform.  Some parts of a dam’s steeply sloped structure are virtually impossible to access even by helicopter, especially in gusty winds or bad weather.  There’s a high risk of workplace injury.  Drones eliminate the risk at greatly reduced cost while the quality of inspections is improved.

Drones are especially critical to have on hand during an unexpected event, such as an earthquake, which can damage dam infrastructure without showing up for weeks or months.  Getting a human team to inspect the whole facility in an emergency is especially costly and time-consuming, often taking days. A drone can deploy and follow up repeatedly to survey potential secondary damage.  Communities served by dams can rest more easily knowing that their dam has been thoroughly inspected so soon after a dramatic and potentially life-threatening  incident.

Drone dam inspections aren’t just conducted by air.  SCE and other dam system are beginning to deploy underwater drones in place of human divers to inspect dam foundations in dark, murky and sometimes unhealthy and contaminated waters. Many concrete dam structures may be perfectly intact above ground but their foundations may have cracked or eroded over time.  Underwater drones can go deeper than human dive teams – and again, at a fraction of the cost.  They can also conduct inspections while the dam’s turbines are still churning, further reducing the expense of the inspection.  And there’s one further advantage:  Underwater drones can test water quality more frequently and across a wider expanse of the dam’s reservoir, ensuring the safety of drinking water.

More refinements of drone dam inspections will likely come if and when the Federal Aviation Administration decides to grant Beyond Visual Line of Sight (BVLOS) authority to drone companies and their pilots.  Drones could conduct routine inspections of dams automatically and with pre-planned flight schedules.  But don’t expect that authority to come anytime soon.  Given the stakes involved, keeping drones away from major dams – unless remotely piloted and monitored and easily disabled if needed – is still a good idea.

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