River Sentry News & Updates

  River Sentry: Predictive Vs Reactive (Part Four) We define River Sentry as a reactive flood warning system.   What does that mean?   Most flood systems attempt to provide predictive notification from hours to days. They use an extensive suite of water sensors in various tributaries, rain gauges, weather radar, soil moisture sensors and other technologies. These combine to create hydrologic forecast models, create thresholds, then issue alerts. River Sentry’s reactive system is different. It accepts a minimized alert window in pursuit of higher performance, resiliency and accuracy.   It positions water sensors well outside moderate flood thresholds existing on the line between significant and dangerous. Most flooding will not activate it. This is by design for metrics explained as probability of detection (POD) and False Alarm Ratio (FAR). POD is an important parameter as low POD scoring is indicative of a system with poor detection ability, a dangerous shortc...

 “I am the watcher on the walls. I am the fire that burns against the cold, the light that brings the dawn, the horn that wakes the sleepers, the shield that guards the realm of men”      -The Nights Watch Oath / A Song of Ice and Fire/ Game of Thrones / George R.R. Martin In weeks, the black sentries will assemble on the Guadalupe. Adorned in black armor, the orders are clear. The watch begins; it never ends. Stand before the protected. Form the line, guard it! It is tragedy that summons them, to prevail against her monsters in the night. Others have tried and failed. Employing all method of water flow sensing gadget and incantation, they watched the rivers and the skies. From a safe perch, the mages of data, radars, modeling, and predictive software claimed to know her, to understand, and worse; to predict her. She rewards the overly familiar with brutal lethality, sending the worst of her demons in the night. 50,000-foot mesoscale horrors; flashing in white ...

The new Texas SB3 legislation calls for installation of sirens. What is their purpose? Flood tragedies and nighttime have a deadly relationship. Approximately 75% of the flood deaths happen at night. Exclude low water crossings and this jumps to 80%. Like a volatile fire triangle, flood tragedies feature a three-ingredient chain: sleep, proximity, and rising water. To prevent the horrors, we must break the chain.   Mother nature owns rising water, and proximity cannot be affected if one is resting so you must attack sleep first. Will the sirens do it? Commercial Fire Code NFPA 72 Section 18.4.5.1 requires an alarm minimum of 75 Decibels (dB) in each sleeping space. A typical city siren produces around 130 dB. Only 500 feet away, heavy rain absorption, loss over distance, and structure insulation lower the level toward 58 dB, far lower than fire code and unlikely to wake anybody. The new legislation defined these as outdoor sirens so perhaps that’s expected but if so, where is t...

It’s 2 AM. You are sound asleep on the fifth floor of your hotel when a fire breaks out. The danger is immediate. The escape window is limited. How do we solve for alerting in this time critical scenario? Do we utilize distant city sirens unlikely to generate sufficient decibel levels to wake up those indoors? How about SMS text warnings to guest phones that may be silenced? Fire code dismisses any such remedies. Loud alarms are required in each room as are lighted egress paths. It makes sense, one must be awake and moving to escape. Before that escape can occur, timely detection of the danger must quickly and accurately occur. Fire alarms use smoke and heat detection to autonomously activate. How do we bring such autonomy to flash flood warning?   River Sentry philosophy utilizes perimeter warning sensors to detect rising water as it approaches. The sensor methodology differs but the desired effect is the same. Get up and get out! We can further examine the flood warning chall...