FloodRISE is a program that predicts high-risk flooding areas. The program works with communities to present residents in Southern California and low-income communities world-wide with information to aid their survival.

By Helena Carlson

Flooding along the coastal areas of California is not uncommon; it happens almost every year around the same time, sometimes more severe than anticipated. Not only does it occur along Newport Beach, but among other areas including San Francisco and Los Laureles, a canyon west of Tijuana, Mexico.

“Most communities tend to find that they’re not as prepared as they should be,” said Dr. Richard Matthew, a professor in the UCI School of Social Ecology and co-founder of the FloodRISE project, “heatwaves and droughts are almost certainly going to intensify, these are immediate issues.”

Matthew and Dr. Brett Sanders, professor and Chair of the UCI Civil and Environmental Engineering, together founded the FloodRISE project in 2014 after receiving a $2.8 million National Science Foundation grant to launch the project.

FloodRISE is an acronym, that stands for Flood Resilient Infrastructure and Sustainable Environments. Flood hazard modeling is the main focus of the project, where the team creates maps through aerial scanning and determines areas of highest flood risk, creating models based off of the data.

Ideas for the project initially surfaced informally between Matthew and Sanders as they found a mutual interest. Matthew thought the idea would be very useful to communicate what the risk of flooding is. He was concerned with poorer communities not being beneficiaries of state of the art thinking, and he knew Sanders had technology capable of starting such a project. Having both joined forces in their respective groups, they hoped that with creating FloodRISE, it could be used as an accessible tool for low-resource communities to use in mitigating flooding and preparing for storms.

“I asked Brett if he had ever started doing this in areas of extreme vulnerability with high levels of poverty, and he thought he would like to try it. We put together an application to see if we could raise some money. So we did, and we raised a few million dollars that allowed us to start this work. We wanted to take our strongest tools and make them relevant to our most compromised places,” said Matthew. Since then, they have continued to raise more as the FloodRISE project is ongoing.

Even when there are light floods, it can pose a health challenge because there is little drainage in the canyons and pools of water attract mosquitoes and release sewage into the community. With steep sides, people can get trapped without easy ways to get out. When it rains, the houses on the canyons begin to slide down, water comes through the bottom and builds up.

At this point, the team has travelled to numerous places around in the US and other areas including Africa and South America. A particular focus has been in the Newport Beach area — where property damage is the main concern — and in the Los Laureles canyon area in Tijuana, near the Mexico-US border — where poverty is more extreme.

“So you have communities in that are living in the canyons, and water comes through, the people are building,” Matthew explained. Severe flooding can be rare in Los Laureles, and for the people living there, the danger is not tangible enough if major flooding occurs once every few decades, “they’re not living for generations and generations, so they don’t have that historical memory.”

Even when there are light floods, it can pose a health challenge because there is little drainage in the canyons and pools of water attract mosquitoes and release sewage into the community. With steep sides, people can get trapped without easy ways to get out. When it rains, the houses on the canyons begin to slide down, water comes through the bottom and builds up.

“Kids can be swept away too,” said Matthew, “every year, kids are killed in this area of flooding.”

Technology has matured extensively since the early 2000’s. Flood hazard models now can predict flood extents, flow depths up to 80% accuracy.

“We can actually start using it to help people, to help decision makers figure out how they can reduce or mitigate the risk of flooding locally,” said Dr. Jochen Schubert, a pHD research assistant at FloodRISE; he has been working on the team since the launching of the project. “I work with Brett Sanders in engineering and we develop very local scale, detailed flood hazard models, these are great models to visualize what flood hazard could be like at the street level and their locations.”

The research team uses models to improve assessment of impact. This impact could be economic or societal; that translates into flood depth and building value to assess the economic damages and how the velocities impact communities. They predict instances of flooding and its respective chance of occurring. A flood that happens every 100 years may have a 1% chance of occurring, that streamflow can be put into a model that represents specific river reach. If the volume of the flow exceeds the capacity of the channel, then the flow will overtop the banks and will spread across the urban area. They can tell where the flow is going — how deep, fast, and which buildings are affected.

“It can help us visualize this information on what infrastructure is going to be impacted,” said Shubert.

Back in 2000, when Schubert first began working with Sanders, the models were very coarse and the predictive accuracy of these models was poor. They could only be used for very big events where there was a lot of water flowing through, and at large scale. Now they could be used at a local scale of individual streets or small towns. Since then the progress in data acquisition and computation power has improved dramatically. 

However, these algorithms have to be consistently changed given a changing environment and subsequently the increasing risk of flooding.

According to a group of researchers at the Nature Climate Change, global damage of flooding may increase by a factor of 20 by the end of the century, if nothing is done to slow the rapidly changing environment. Impacts of climate change are found to be dwarfed by socio-economic growth, and proportionally impact poorer communities the greatest. Globally, countries in Africa and Southeast Asia face greatest risk from flood damage. In Southern California, impoverished neighborhoods are along the coast. Homeless individuals living by the the Angel Stadium riverbed in Santa Ana sometimes find themselves waist deep in water after a heavy storm or in severe cases — are swept away.

Current FloodRISE maps represent present conditions in the environment, however as new information from tide and rain gauges come in, the maps “need to be revised on a continuous basis,” said Schubert. It is important to develop stationary models that predict flood risk within short periods of time, but these predictions might only be valid for the next 5-10 years. Non-stationary models are more complex, but take variability of sea level rise and rainfall rates into account.

“As we understand more and more about climate change, we understand that it’s happening but there’s going to be a lot of variation, it’s going to happen at different speeds and it’s hard to say for sure what will happen in one place over the next 50 years,” said Matthew. Climate change can cause long droughts, which often end in massive flooding, “we expect more severe storms meaning more water falling at high speeds in an area.”

Matthew said he doesn’t see FloodRISE ending anytime soon and he hopes that it won’t because there was too much yet to be done. He wants FloodRISE to become a trusted center in California for producing reliable flood risk models that people can use to make better decisions about managing flood risk, particularly for low-resource communities that often don’t have very many ways in which they can fully understand.

“I’d like to see this grow, modeling more areas, and we’re going to put these cases online. What we’re trying to do is figure out what’s the best way we can share this. Our goal is for someone, anyone to go online and make perfect sense of this,” said Matthew. His main focuses are to expand the locations modeled and make it user accessible for everyone. “If we can do that in the next 10 to 15 years, it’ll be huge.”