River Sentry

River Sentry Always watching, always ready. River Sentry builds innovative and cost effective flash flood warning solutions to save lives.

09/05/2026

Texas Senate Bill Three (SB3) calls for the installation and operation of sirens in a strategy to provide flash flood warning.

It’s not a new strategy but it is unproven. Despite over a century of municipal siren usage, we have found no record of a successful flash flood intervention event ever…anywhere.

This is not a criticism of the solution itself but recognition that it requires careful consideration as there is no established successful roadmap.

Given this approach, strict adherence to established acoustic warning standards is prudent.

FEMA’s Outdoor Siren Guide CPG 1-17 provides established guidance. It’s a 1981 reference but still checks out. We maintain this is last century’s technology and established physics doesn’t change with time. Let’s explore those standards.

“The most important factor that determines the detectability of a sound is the signal-to-noise ratio. The noise portion is the ratio of the background noise at the listener’s location.

Thus, for a given level of warning, the background noise is CRITICAL to determine warning signal effectiveness. (CPG -17).

This isn’t that complicated for the same reasons you may not hear your phone ringing at a rock concert as ambient noise is higher than your ringer.

Given that deference, what is the background noise level during an extreme mesoscale thunderstorm next to a raging river?

Without that number, we cannot begin to meet any standard in warning let alone publish a coverage map.

There are established acoustic engineering firms who design city wide mass warning systems who might have been commissioned to explore these issues.

Of the 36 project contributors on the 83-page Texas Water Development Board Siren Guide, we cannot find a single acoustic engineering resume or contributor.

This is difficult to explain considering the severity and recent loss of life.

To randomly install sirens along our riverbanks utilizing siren manufacturer sales brochures uncorrected for ambient is misfeasance and a serious deviation from established standards in acoustic warning.

Furthermore, having those solutions signed off by anyone but a credible acoustic engineer is highly problematic.

We foresee increased fatality risk and massive liability for our counties should they field these warning solutions without storm validation or worse, advertise coverage areas of warning protection that are not scientifically achievable.

Given this public health and safety issue, River Sentry is commissioning two out-of-state Acoustic Engineering firms to provide expert background noise validation.

Additionally, they will provide a corrected performance range for the current county siren solutions installed in proximity to ours in Kerr County.

Hunting Submarines and Flash Floods.Two unrelated subjects? Hardly, both include acoustics, water, lethality and time cr...
08/30/2026

Hunting Submarines and Flash Floods.

Two unrelated subjects? Hardly, both include acoustics, water, lethality and time critical threat mitigation. The first uses sound to take life, the latter to save it.

Thousands of miles out to sea, airborne submarine hunters deploy a mass of sensors to detect an adversary they can only hear, not see. The enemy will employ everything it can to remain undetected.

Both will utilize the environment to either detect or avoid using acoustic science.

The hunter will first deploy environmental assessment buoys.
These devices will slowly sink into the depths using radio telemetry to transmit ambient noise levels, salinity, and water temperature.

These parameters are required to facilitate tactics, localization, and prosecution. Understanding signal to noise ratios and sonic layer depths are critical as the adversary will attempt to exploit these. The unfamiliar will lose the contest.

For the hunted, the match is deadly and unwinnable. Just like those sleeping in flash flood danger, the submarine can only escape.

The airborne tacticians and sensor operators will do everything to prevent this using the aircrafts speed and maneuvering advantage to build a massive sensor net slowly tightening the trap.

Quiet passive detectors will attempt to find range and bearing listening for discrete machine or propeller frequencies above ambient noise.

To employ these tools correctly, one must know and understand the importance of ambient noise.

To employ lethality, tactics change to loud active sonar pings that bounce off the submarine hull. Range, bearing and depth are learned.

The situation is now deadly, and the submarine will use every tool available to break contact including noise emitting decoys and evasion tactics.

Far above the submarine, kill parameters are carefully programmed into the weapon, a bomb bay is opened.

The acoustic onslaught ceases only to be replaced by a louder and faster sonar ping. An unmistakable and ominous frequency appears on submarine acoustic displays.

The acoustic signature is that of a torpedo propeller at active acquisition speed. The sonar pings are louder. The bearing is constant; the range is decreasing.

The contest is lost.

In the next post, we will explore further usage of sound in flash flood acoustic warning systems (sirens) and explore best practices vs current deployment outcomes.

Written by Ian Cunningham, CEO, River Sentry and former P-3C Orion Mission Commander and anti-submarine warfare (ASW) Instructor Pilot.

08/21/2026

Mesh Networked Flood Warning: Let's talk LoRa.

Brace yourselves; it is going to get technical. The River Sentry towers will utilize WIFI, Bluetooth, Cellular, and LoRa in their communication roles.

Every smart phone has the first three. The last and arguably most important is LoRa which is an acronym for Long Range. This title describes the unlicensed frequency band of 902-928 MHz. This status was established in 1985 for unlicensed commercial radio tech.

Why is this relevant? Being an unlicensed spectrum, all users must share the frequency band. To regulate usability, the FCC limits transmitter/dwell times and restricts power output to a single watt.

Effectiveness is achieved by frequency hopping or spreading the transmission across multiple frequencies in the same band range. Only small packets of information can be processed under these constraints.

One could never stream video or talk, but text messaging is achievable up to a few miles under our intended conditions.

Advantageously, these transmitters use very little electrical power allowing solar panels or long duration batteries for power. We like batteries. They are simple, dependable and don’t fail during extreme thunderstorms.

Upstream towers detecting dangerous high-water conditions will send small byte encrypted warning signals to downstream and nearby towers.

As those warning signals travel from tower-to-tower, they will alert residential warning devices in bedrooms which themselves; will retransmit those warning signals.

Those residential devices (Flood Cubes) all serve as an internet gateway should a usable WIFI be accessible.

Once the server is alerted, similar warning orders are issued to every internet connected device and cell enabled towers. Server directed warning transmissions will travel via LoRa to upstream towers. Additionally, mobile app users will receive geo-location specific warnings.

Simultaneously, Residential Flood Cubes may trigger towers with a server directed warning transmission passed over the internet, then via LoRa from Flood Cube to Tower.

The sum advantage is three separate autonomous ways of triggering a flood warning coupled with massive levels of redundancy.

Combine this communication capability with the 200+ water sensors located in the 100+ towers in Kerr County and a truly formidable flood warning system begins to emerge.

08/17/2026

It was great to join Eric and Dennis in the morning for a long conversation about River Sentry and our ongoing efforts. Click on the link of you are interested in listening.

The dark economics of flood warning.The warning systems installed on the Guadalupe River performed better during the Jul...
08/15/2026

The dark economics of flood warning.

The warning systems installed on the Guadalupe River performed better during the July 16th flood event. Still, we experienced loss of life. Water again found people at night where they slept. We have more work to do but how do we afford it?

If we calculate cost per mile of flood warning, this quickly becomes discouraging. Between consultants, engineering, purchase, and install, we estimate at least $100,000.00+ (excluding sensors) price per mile of outdoor warning capability for current solutions being pursued by public agencies.

This reflects outdoor siren technology currently proposed and approved under the Texas SB3 Siren plan administered by the Texas Water Development Board.

Texas has hundreds if not thousands of miles of inhabited rivers, streams, and high-risk dry creeks. It simply isn’t economically feasible to pay this price per mile for acquisition nor the ongoing expensive telemetry subscriptions that run thousands per month per device.

This puts our public officials in a very difficult position of choosing the “have’s” and the “have nots”. Such division will create community friction. The outcome isn’t fair and cannot afford to be fair. How can we improve this?

A standard River Sentry RS-1B wireless unit will cost approximately $15.5K wirelessly covering two miles at a cost of $7750 per mile. The encrypted LoRa radio transmissions can activate an unlimited number of residential home devices (Flood Cubes) between towers. The economics of River Sentry are superior. The science is too.

Most flash flood deaths happen at night, and very few sleep outside during Texas summer thunderstorms. This solution is far more relevant to how people perish during flashfloods, which is at night and indoors.

Simply put, with the Texas allocation of $50M, River Sentry could potentially cover over 6000 miles of linear river/creek front with a much higher standard of warning capability.

This will require public leadership to change course, embrace innovation, and pursue higher standards in flash flood warning.

08/09/2026

Most who follow this page are aware we had six towers involved in the River Run RV park evacuation on July 16th. Interestingly, we had two other towers activate upstream to specification but not to intention.

The first was one of the six guarding Vista Camps. In conversations, we have learned of local rain reports of 12 inches overnight. The standing water and run off was extremely high and began entering the buildings our tower was guarding.

Our system misinterpreted this as a flash flood and activated. We will raise the elevation of this single unit which was already mounted in a steep sloping area.

On a positive note, the counselors heard it and followed instructions by rapidly exiting the area.

The second activation was a residential single tower at Pawnee Point and involved high levels of standing water. Essentially, the mild sloping pasture became a shallow lake and water began entering the guarded residence.

We offered to make adjustments to the owner but she declined. If the water levels were getting that high around her house, she wanted warning. Its a valid flood case, and while not a flash flood, these conditions could impede escape. It may be best to egress early.

We agree and this install is her private residential solution. She gets what she wants.

We do enjoy the product feedback on our solutions and find special entertainment in the narrative we are "just taking sp...
08/07/2026

We do enjoy the product feedback on our solutions and find special entertainment in the narrative we are "just taking speakers and lights off police cars and sticking them in tubes."

Factually, they are correct and we do this on purpose. To truly stop flash flood tragedies, we have to drive cost of acquisition down while increasing capability; not always possible without innovation and creative problem solving.

By choosing established mass produced proven quality components, we can safely assume they will perform well here. This allows the cost benefit of mass production, a ready supply, reputation, and history.

Furthermore, we want flash flood safety easily accessible by home owners, low tax base municipalities/counties, and revenue constrained businesses. Being "safe" shouldn't be expensive or out of reach.

This repurposing of "other" industry components into a flash flood role leads to interesting conversations. In our search for inexpensive but durable water sensors, we turned to the maritime industry. They were initially skeptical about liability and performance in our role but we argued our case.

In a storm at sea, a fishing boat that is taking on water and a flash flood threat IS the same problem. Survival depends on quickly detecting water where it shouldn't be. That must occur immediately with maximum resiliency.

They agreed and now produce a special version for us with a test circuit. That company is Water Witch of San Diego, CA. Two of their sensors reside in each River Sentry.

When floodwaters rise in the middle of the night, early warning can mean the difference between life and death. River Se...
08/06/2026

When floodwaters rise in the middle of the night, early warning can mean the difference between life and death. River Sentry is designed to wake people sleeping in riverside campgrounds, RV parks, and other flood-prone locations with powerful 130 dB sirens. Bright built-in warning lights direct the way to safety, while clear voice alerts powered by the ELK-120 Recordable Voice Module provide simple instructions to the disoriented. By giving occupants precious time to react and safely evacuate, River Sentry is helping protect lives when every second counts.

https://riversentry.com/

First on the Frio River! In partnership with the Renee Smajstrla Memorial Fund and Hill Country Youth Ranch, we official...
08/06/2026

First on the Frio River! In partnership with the Renee Smajstrla Memorial Fund and Hill Country Youth Ranch, we officially commenced project construction to install 4 RS-1A Towers at the Big Spring Ranch for Children near the headwaters of the Frio River near Leakey, Texas.

These towers will guard both staff and youth housing, provide localized flood warning, and serve as a valuable collection of high water sensors serving the entire down river community. This project is closely aligned with both River Sentry's mission to end flash flood tragedies and the Renee Smajstrla Memorial Fund's mission to promote increased safety.

We will have more to share about this special project soon.

You may learn more about these incredibly valuable organizations here.

https://livelovenaynay.org/pages/about-the-foundation

https://www.youth-ranch.org/big-springs-ranch-for-children

08/06/2026

What sets off the River Sentry Flood Warning systems?

In most cases, water approaching sleeping quarters begins the process. What occurs after varies. Here are some cases and methods.

1. Single unit localized water detection/alarm. (Seen here)

2. Wireless(LoRa) activation by a family unit on a campus. First detecting activates unit family.

3. Owner manually activates via BT mobile app. (Can only control owned devices)

4. Upstream high water detection at selected upstream towers (owner preference)

5. Maximum Warning Condition (MAXWARNCON) Upstream tower directed (LoRa) during a dangerous high water flood event as measured by towers at multiple locations. Autonomously activated. Locks out owner controls for 6 minute alarm duration. Bypasses audio safety protocols allowing max volume performance after 4 minute volume ramping. Tower wireless triggers all residential warning devices in range.

6. Server directed activation via Wifi or cellular to tower/LoRa/tower. During an extreme high water event, the tower computers will inform the server via cellular or wifi gateway of the conditions.

The server now assists by also ordering all towers to activate through select tower cellular connections. Additionally, it provides geo location specific alarms through the mobile app, conducts robocalls, and other data output. The server is not a required participant and the app is an auxiliary warning function.

The main certified warning solutions(towers/residential devices) autonomously function without the power grid, cellular, broadband/internet or a human decision loop.

The collective purpose of these devices is to detect deadly conditions and initiate the immediate evacuation of a 50-mile river in minutes. We will utilize fire code adherent warning devices that are proven to wake people while creating critical time and space to escape....without breaking trust with false or irrelevant alarms.

Address

4060 CR 201
Liberty Hill, TX
78642

Website

Alerts

Be the first to know and let us send you an email when River Sentry posts news and promotions. Your email address will not be used for any other purpose, and you can unsubscribe at any time.

Shortcuts

Share

Category