Pilot project meant to keep motorists off flooded roadways finds success in Norfolk, could spread throughout Hampton Roads

Traffic and high water mapping technology out of Australia showed enough promise helping Norfolk navigate its flooding woes during a 9-month pilot project that the city has decided to expand and continue its use, just in time for hurricane season.

The city joined Waze for Cities in 2017 to get access to real-time traffic data reported by users, which included reports of flooded roads, but the city wanted to see if the app could go beyond eyewitness reports and instead tell users which roads would be flooded ahead of time. For the last 9 months, it’s been part of a pilot program testing the first-ever integration flood mapping technology into the Waze navigation app.

FloodMapp, an Australia-based live flood modeling company, designed software that could incorporate rainfall and tidal flooding data into a real-time model of water levels and map it onto satellite images of the city. This data would then be sent to Waze which would populate its map with icons showing flood hazards and closures. A “closure” is triggered by water 1 foot deep or higher, which is the city’s standard for a non-passable road.

When Norfolk experienced major flooding in May, as higher-than-normal high tides combined with heavy rains and wind, the software was able to automatically reroute Waze users around roads closed by flooding ― a first for the technology.

“This kind of integration of real time hydraulic flood model and real time analytics capability to predict water over the roads and then integrate that into real time road closures and hazards in Waze — it’s never been done in the world before, said Juliette Murphy, CEO of FloodMapp. “This is really the first time we’re seeing this technology piloted, in Norfolk, and we’re finding it’s working really well.”

Use of the rerouting feature in May meant the city didn’t have to send staff out to evaluate road conditions or put up road-closure signs.

The software has garnered international interest, and other cities in Hampton Roads are looking to implement it as well, according to Paul Robinson, executive director of RISE Resilience Innovations, a Norfolk-based nonprofit that challenges companies to solve resiliency issues through technology and funded the city’s initial pilot program.

Waze works by allowing users to report road conditions and factoring that information into the routes it presents to others. It then prompts users passing previous reports in that area to confirm whether a hazard is still there or not. Since the flood detection element got up and running in October 2021, Waze users have given a “thumbs up” or “thumbs down” on flood hazards about 5,800 times to the roughly 2,700 individual flooded roads reported during that time period, according to Murphy.

This level of user feedback, while it doesn’t present a full picture of how many people benefited from Waze’s rerouting function or hazard reports, is rare for data scientists, providing them with a greater understanding of how accurate their models are, Murphy said.

“It’s been quite incredible to me to see the volume of which the tool is being activated and called on to report flood predictions and flood hazards,” she said.

Waze declined to share the app’s usage data with The Virginian-Pilot.

Kyle Spencer, Norfolk’s chief resilience officer, said prior to this pilot program, Norfolk and Hampton Roads relied on a system of static sensors throughout the jurisdiction to make decisions about road and floodgate closures. He had already identified 50 key locations where they would have installed sensors.

There are shortfalls to that approach. For one, it’s more expensive. The Hampton Roads Planning District Commission bought 20 sensors for about $200,000, and they cost about $20,000 in maintenance each year, according to Spencer. The cost of the FloodMapp software is a fraction of that at $50,000 per year, which the City of Norfolk approved for its 2022-2023 budget.

But the sensors only alert for the area they are placed, which may not provide the information needed about whether or not a road should be closed to vehicle travel, Spencer said.

“That’s the advantage this software brings us is that it creates that flood depth inundation layer and we can use that to geospatially identify everything that is underwater instead of just one location,” Spencer said.

The data from FloodMapp can be used to provide more nuanced and practical information about what high-water forecasts mean for neighborhoods, Murphy said.

“So there’s tidal flooding predicted ... to reach 5.6 feet but if you live in an apartment block, what does that mean at your street? Because the topography and height of the land and your asset flood height is different everywhere,” Murphy said.

FloodMapp uses a combination of topographic data, tidal stream gauges, river and stream gauges, rainfall observation and rainfall forecast data to simulate tidal and rainfall-induced flooding. Murphy said that they’ve compared their predictions with the observed flood areas using satellite imagery, crowdsourced photo observations and high-water marks and have reached as high as a 96% accuracy.

Outside of helping residents stay safe during hurricane-level events, Spencer sees the technology’s ability to mitigate the day-to-day “nuisance” of flooding as the biggest impact on residents’ lives.

“It gets you to your soccer practice, your doctor’s appointment when it’s high-tide and it’s flooding in your neighborhood — to me, that’s where we’re really going to see a lot of benefit,” Spencer said.

The software will also help Norfolk build systems to drain flood waters and plan construction of pump stations, he added.

After the city decided to re-up the program, Spencer’s goal was to have no interruption in the service between the end of the pilot program’s funding on June 30 and the start of the new fiscal year on July 1, but on Wednesday he said the service was not yet up and running due to ongoing paperwork. The subscription includes access to other apps that work in the background of Waze and allow city officials and emergency management personnel to prepare for and respond to flooding events.

Norfolk’s emergency response staff reviewed FloodMapp’s functionality over the course of the pilot program and are in discussions about how to use it to help them do their jobs. Murphy said emergency managers in Australia have used the programs to give 24-hour evacuation notice to people in the path of a flood, but in some flood-prone river basins, they’ve been able to provide up to 10 days notice.

Spencer said that this technology is part of the city’s larger effort to prepare for the increasing extreme weather events expected in the coming years as a result of climate change.

Infrastructure upgrades, such as surge barriers and floodgates, are a work in progress in Norfolk to protect the city from flooding. In the meantime, Spencer said use of the Waze app is “sort of like a ‘Band-Aid’ — a short-term tool in the toolbox so we can function and be a prosperous city.”

Gavin Stone, gavin.stone@virginiamedia.com