How to build awareness of flood risk and gain buy-in for flood control measures

Floods are one of the most devastating events to strike a community—costly in terms of lives lost, damaged or destroyed homes, economic disruption, and damage to critical infrastructure. However, improvements in technology are helping local governments provide accurate assessments of flood risk, so steps can be taken to provide early and accurate warning of flood events, minimize potential losses, and improve outcomes and overall resilience after a flood occurs.

What’s missing from current methods of managing flood risk?
To understand how local governments can better manage flood risk, it is important to understand how this work is done at present.

Many municipal and county governments rely primarily on Federal Emergency Management Agency (FEMA) Flood Insurance Rate Maps (FIRMs) and Flood Insurance Studies (FIS) for flood information. Per current standards, these flood hazard products use a deterministic assessment of six flood events: the 10% annual chance (10-year), 4% annual chance (25-year), 2% annual chance (50-year), 1% annual chance (100-year), 1% annual chance “plus” (100-year plus), and 0.2% annual chance (500-year) flood events based on historic data.

The 1% and 0.2% annual chance events, or the Special Flood Hazard Areas (SFHAs), are the mapped flood events shown on the FIRMs. However, extreme rainfall events, which are becoming much more prevalent, are not well depicted in the existing FEMA Risk Mapping, Assessment, and Planning (Risk MAP) datasets. Pluvial (rainfall-related, or “flash”) flood information is not generally available or accessible to communities. It is also rare that local governments have real-time flood risk information for decision support, especially in low population areas, disadvantaged communities or near un-gaged streams.

Three main challenges local communities face are obtaining information based on:

• Current conditions: Most available flood risk information is based on historical hydrologic data and does not account for extreme rainfall events. Current extreme rainfall events are often beyond the 1% or 0.2% annual chance events. Also, due to the large investment of funding and labor required for traditional modeling and mapping methods, analysis may not account for current infrastructure and impervious development.
• Pluvial or flash flood risk: Although a significant risk, pluvial analysis is not available to most communities in the United States. These types of events are often extremely costly because they affect infrastructure outside of the SFHAs.
• Available resources: Most communities are unable to acquire floodplain studies or real-time warning tools due to limited resources and funding. It is also difficult for communities to prioritize flooding over other hazards that may impact the population.

Municipal leaders may be aware of increased flood risk, but it can be challenging to obtain buy-in and associated financial support to protect against an event that may not happen. It’s hard to determine how much to allocate for flood mitigation measures.

But the potential implications can’t be ignored, including considerations to health and safety, the economy and environment, and overall growth and advancement.

Solutions lie in community involvement
The solutions to managing flooding effectively come in two aspects—human and technical. Let’s start with “human.”

• Look for community involvement and interest groups that share the vision and can support the municipality’s efforts. In addition, look to engage interested parties and groups that are not necessarily in alignment in order to better represent the unique profile of your community. Having diverse inputs and stakeholder priorities minimizes the risk of confirmation bias, while fostering partnerships to resolve meaningful change through real time solutions. Creating these groups or organizations can also provide resources and cost-sharing opportunities.
• Look for ways to meet shared goals among municipal departments—e.g. Parks & Recreation may want to develop more parkland and multi-use trails, so they may support measures that limit development of floodplain areas.
• Access state and federal funding through supporting priorities of agencies such as FEMA, U.S. Environmental Protection Agency (EPA), U.S. Department of Housing and Urban Development (HUD), and U.S. Department of Agriculture (USDA). For example, in your funding requests, highlight proposed flood control plans which involve constructed wetlands and other measures that can be considered nature-based solutions.

The role of information technology
The technical aspects of flood management also play a major role in increasing awareness and gaining buy-in and support for mitigation efforts. As mentioned, current flood risk management practices may not keep up with current development. This may mean that there are more hard surfaces with increased runoff than the latest FIRMs would indicate, and a higher risk of flooding. Major technological developments that can complement and enhance current methods of flood risk management are:

• Artificial intelligence (AI) based flood modeling tools can quickly and accurately model current and future risks, such as increased storm frequency and severity, as well as multiple flood risks such as riverine (fluvial), rainfall-related (pluvial) and coastal flooding, which was previously costly and time intensive to model. Because these models can be effectively deployed, current condition inputs such as the latest LiDAR and land use datasets, can be incorporated as new data becomes available. 
• Internet of Things (IoT) data, such as gages or sensors, in public domains and commercial sources, can provide real-time information on potential risks and more accurate information on possible upstream impacts.
• Quick response tools. With AI-based flood models, it’s possible to enter real-time IoT data such as weather or gage information and provide emergency responders a prognosis on when and where a flood is likely to develop over time.

An example AI-based flood modeling tool displays a community flash flood risk probability for a custom simulation of 10 inches of rainfall over 24 hours. The higher probability flood risk areas are displayed in red. Image courtesy of Stantec.

In this way, AI-based flood modeling becomes a transparent, verifiable, data-driven method to perform readiness and preparedness actions, mitigation and resilience planning, capital spending, and real-time emergency response to protect lives, property, and infrastructure. It also provides a means for local communities with limited budget and schedules to assess best available data where there may be outdated information, no information, or no instrumentation data available.

Pairing advanced technologies with local expertise and engagement creates a new level of understanding of the need to support measures that will protect our communities.

Katherine Osborne is a principal at Stantec with more than 14 years of experience in floodplain modeling, management and resiliency. Osborne’s focus is integrating the latest digital solutions in floodplain management initiatives including public outreach, information management, flood warning, disaster response, emergency management, and mitigation. Her goal is to create ongoing awareness of innovations for our clients to achieve better, faster and cost-efficient results.