An image showing drones for hydrometry.

A different point of view changes nothing but it can change everything. Last week I wrote about how unmanned Aerial Vehicles (UAV), also known as drones, could be used for Large Scale Particle image Velocimetry (LSPIV) to get surface velocity measurements, which when combined with surveyed cross-sections can produce extreme flow gaugings. That same drone, equipped with the same camera, can also provide the cross-sectional...

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An image showing stage discharge rating curve.

Extreme flows are extremely hard to gauge, hence we get very few gaugings to accurately define the top-end of stage-discharge rating curves. This is a problem. Whereas empirically calibrated functional relationships can be trustworthy for the purpose of interpolation, they can be notoriously unreliable for extrapolation. One needs to be very careful about extrapolating any rating curve to an ungauged extreme....

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Two people in deep flood water.

The Governor of the State of South Carolina points out to reporters in every press conference that the floods are a one-in-1000 year event. In other words, the devastation from these floods is not our fault, this is an extremely improbable event and there is no way we could have been prepared for it. The cost of the flood is estimated at USD 1 billion and...

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Graphic of Selected Significant Climate Change Anomalies and Events worldwide.

Extreme drought in many regions of the world is creating an opportunity for many stream hydrographers to record a historic event. A report from Poland shows ‘no end of secrets’ being revealed by rivers as they dry up. July 2015 was the hottest month in recorded history. The Clausius Clapeyron relation tells us that the moisture holding capacity of the atmosphere is non-linear with temperature. Over...

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Ducks on an algae-covered pond.

The theme of the Canadian Water Resources Association (CWRA) 2015 conference in Winnipeg this year was “More Extremes? Preparing for future challenges to Canada’s water resources.” Fittingly, the North American Stream Hydrographers (NASH) held 3 sessions that were dominated by discussions of how to resolve several of the daunting challenges inherent in measuring water. All of the other sessions – whether talking about water quality; policy, planning...

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A photo of Todd River near Alice Springs.

In ‘The Other Extreme - Part 1: the Measurement of Absolutely Nothing’ I presented an argument that the difference between ‘exactly zero flow’, and ‘nowhere near enough water to generate flow’ can be important from a water resource management perspective. We rely on discharge data to inform us about water availability. This reliance is based on an assumption that discharge data represents information both about the hydrology...

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