Open Source Flood Warning & Hydrography Projects by Adam Murphy.
TDMA slot design, radio planning and network optimisation for ALERT2 flood warning networks.
Every station on one map. Inbound coverage at 150 MHz over real terrain, chain verdicts through every repeater hop, and a TDMA slot plan built from the propagation model — with the assumptions it made written on every page.
Read flood-warning radio telemetry off the air with a $30 receiver.
ALERT and iFLOWS field stations across NSW report river and rain readings on 151.5 MHz as short AFSK bursts. This project decodes them: a desktop Python decoder, and an Android app that hosts the RTL-SDR over USB and runs the whole DSP chain on the phone -- no PC, no network, no server. It reports the sensor ID, the value, and the four raw bytes they came from, so a reading can be checked rather than trusted.
A second, independent path from a LoRaWAN gauge to an ALERT radio.
A Milesight radar gauge already reports over a commercial LoRaWAN network. This project adds a private gateway that hears the same sensor directly, decodes it locally, and serves the level over SDI-12 to an ELPRO ERT-A2 field station -- which puts it on the ALERT VHF flood-warning network. If the LoRaWAN backbone fails mid-flood, the reading still reaches the radio.
Measure river surface velocity and discharge from phone video.
A native Android app that measures river surface velocity from video using Space-Time Image Velocimetry (STIV). Point a phone at moving water, draw search lines parallel to the flow, and the app builds a space-time image along each line: surface texture drifting downstream shows up as diagonal stripes, and the stripe angle -- found with a structure tensor -- is the pixel velocity. Calibration turns that into metres per second. Add depth soundings and it estimates discharge by the velocity-area method.
A radar gauge on Sydney Harbour, published as it comes in. It is a water level and nothing more — it is not part of any of the projects above.
Sydney Harbour
Contact: adam@floodsentinel.com.au
The three projects are MIT licensed. None ships any agency sensor register or key material. They are field engineering on a live warning path, published because the reasoning may help others — not products, no warranty. Gauge data is published as-is for a test installation and must not be used for safety decisions.