How does the Flood Network operate?
The Oxford Flood Network is our demonstration network which uses the power of crowdsourcing to collect flood information at a much higher resolution than was previously economical.
This kind of information is useful to local authorities who have to deploy demountable flood barriers, sandbags and staff around the city during times of flooding and need to disseminate information about road closures to the public via the media. Hydrologists use this live and historical data to improve their models which they use to calculate future flood risk.
By deploying sensors in the community: under bridges, in back gardens and even under floorboards, we're able to monitor water levels in more detail and provide real-time updates of levels around the city. So how does it work?
Our tiny low-power sensors used in Oxford Flood Network monitor water levels by using ultrasonic pings to the water surface below. We mount them under bridges or on overhangs to track water levels. We get Floodwatchers to adopt the sensor and connect them through their broadband onto the Internet.
The hardware has developed from a quick proof-of-concept with a glue gun, to a Sugru-encased mount, an IP55 junction box through to the v4 sensor device we use today, which is IP67 protected (dust and immersion-proof), with custom PCBs for simple assembly and diagnostics capability.
The sensor device, left, monitors water levels from above the water surface and transmits the readings over wireless to the gateway, which is attached to a Floodwatcher's broadband and back to the internet.
Typical installations are over minor streams and ditches. These are not classified by the Environment Agency, but often lead to flooding of streets, gardens and properties.
4) Apps and Maps
A mobile-friendly web app is used to manage the sensors and gateways to make sure they're all running and checking in at the correct times. Nominet R&D developed the system around the Oxford Flood Network and we've spent many hours standing with cold hands in ditches waiting for missed telemetry messages developing ways to deploy the hardware more easily.
Finally, the data appears on a community Flood Map. (This is in closed beta at the moment but should soon be opened up.) The river segments are highlighted in different colours according to current conditions vs local knowledge of likely flood levels and the historical data can be viewed and zoomed. It also incorporates live data from the Environment Agency's feeds to further improve the picture.
Feeding the data to existing flood models will improve their accuracy and allow authorities to make better decisions based on live data, meaning faster response times.
Working together we can make communities more resilient and reduce the damage and inconvenience of flooding.
As we develop a commercial product we recognise that the community deployment model isn't always suitable. We're working with some off-the-shelf hardware to gather our data and make trial deployments. Many wireless options are available and together with Love Hz we're researching technologies such as LoRa, GPRS, TV Whitespace and SIGFOX for different situations.
If you have a specific location or project in mind then get in touch with us by email on firstname.lastname@example.org or on Twitter.
This article was first published in the Oxford Network blog in September 2015.