River Sentry News & Updates

We have now covered detection, false alarms, and trust but the effective escape loop is not complete. For the final solution, we must address sleep and proximity. Proper mitigation requires solutions in varying scenarios including those clear, but adjacent to flood plain boundaries. Recent Texas “SB1 Camp Safety” legislation reduces risk for youth camps by elevating lodging outside the flood plain. This only reduces risk; it does not eliminate it. On July 4 th, significant flooding occurred outside the flood plain. Rio Ancho, an upscale gated subdivision on the San Gabriel experienced significant flooding. Several residents required rescue from their homes. This neighborhood was built outside existing flood plains. Several miles away, Sandy Creek, a minor tributary in Travis County, tore through a neighborhood resulting in ten deaths. Just north in Williamson County, an unfortunately named “Little Creek” over flowed and swept away a woman in her residence behind the Hope House fam...

From 2010 to 2020, Under the EU Copernicus program, Germany and Belgium worked together to build a cutting-edge Flood Early Warning System (FEWS) that would be collectively known as the European Flood Awareness System (EFAS). It was for good reason as floods have long plagued the region. The worst occurred in 1962 killing 362 people in Hamburg. EFAS was the pinnacle with tens of millions spent on the most modern sensors and software available. On July 11 th , 2021, EFAS began the first of days of increasingly severe flood warnings with associate rain fall predictions. In the Valley of Ahr, these warnings were met with little apparent effect. On the afternoon of July 15 th , rain predictions foretold a river rise of 19 feet, an apparently acceptable risk for local leadership. Evacuations were not ordered. An additional flood warning was issued at 3PM. The local population seemed unfazed, perhaps desensitized by lesser floods in what was a common flood prone area. The multitude of warn...

False Alarm Ratio (FAR) is the measure of alerts to actual events. A missed significant flood event could be a devasting failure for a Flood Early Warning System (FEWS) however, this only affects Probability of Detection ratios (POD). What if you successfully predict a flood event, issue a warning, and it still results in incredible tragedy? How do we account for this? A missed flood event is a significant failure, but a high FAR score is a slow death of 1000 cuts. There are no free warnings, and each unconfirmed notification slowly degrades system legitimacy. This simple human behavior equation was first captured by the ancient Greek storyteller Aesop, who famously titled the fable, “The Boy Who Cried Wolf”. FEWS purveyors attempt to capture this through FAR scoring but this doesn’t capture the totality of the problem. Flooding can be highly localized. If a flood warning is issued for a 200-square mile area affecting 10 tributaries and flooding occurs on one tributary, the FEWS wa...

Probability of Detection (POD) ratio is the major metric of the Flood Early Warning Systems (FEWS) arena. It is the measure of events divided by warnings plus missed events. The perfect ratio is 1 flood warning per flood event, no missed events. A 1/1 ratio can simply be expressed as 1…perfection.   It sounds simple, it is anything but. The European Flood Awareness System (EFAS) is estimated to have cost over $30 million and hovers around POD .70. That ratio falls in the more mountainous and remote areas. How is some unknown new tech company in central Texas going to beat that kind of score? It’s a great question, let’s explore it. Before we compare apples, let’s define the arena. EFAS is a regional system attempting to provide flood warning over a large geographic area utilizing a myriad of sensors and software solutions to provide predictive warnings prior to an actual flood event.   River Sentry builds localized area protection with additional downstream advanced warn...