From Washington to California, flood defense operations are currently in full swing as a series of powerful atmospheric rivers continue to impact the western United States. These weather systems are bringing prolonged, heavy rainfall that is leading to widespread flooding across coastal regions, river valleys, and mountain communities.

While many flood defense efforts are led by state, county, and municipal agencies, homeowners can also take important steps to reduce the risk of floodwater entering their homes. Understanding how floodwater behaves—and which flood barriers perform well under extreme conditions—is critical.

What Is a Flood Barrier?

A flood barrier is a temporary or permanent structure designed to prevent floodwater from entering homes, buildings, or neighborhoods.

Temporary flood barriers come in a variety of designs, including soil-filled containers, water-filled tubes, and metal or aluminum panels. Other flood barrier designs use air-filled tubes or water-activated flotation devices. Homeowners may also use DIY flood protection methods such as raised planter boxes, earthen berms, or sandbags to help prevent water from reaching their homes.

Not all flood barriers perform the same, especially during severe flooding involving fast-moving water, debris, and erosion.

What’s Driving the Current Flooding in Washington and California?

Atmospheric Rivers and Saturated Ground

Atmospheric rivers carry massive amounts of moisture from the Pacific Ocean. In recent storms, much of this precipitation has fallen as rain rather than snow, quickly saturating the ground from coastal areas through the Sierra Nevada and Cascade mountain ranges.

Once the ground becomes saturated, additional rainfall rapidly runs downhill, overwhelming rivers, streams, and drainage systems. Flooding develops quickly. In some areas, levees have failed, while in others, tributaries have filled with debris. These conditions leave very little time for homeowners to respond.

Why This Flooding Is Especially Dangerous?

Limited Time to Respond

Many homeowners do not realize the scale of flooding until water levels are already rising. By the time flooding becomes apparent, it is often too late to develop an effective plan to defend their property.

Floodwaters Exceed Standard Barrier Heights

Most common residential flood barriers are designed to protect against 3 to 4 feet of water or less. Current flooding in parts of Washington, California, and Oregon has exceeded these levels, rendering many barriers ineffective due to overtopping.

While taller flood barrier options exist, increased height requires greater cost, planning, and deployment time. Many homeowners who flooded did not anticipate five feet of water inside their homes and were therefore unprepared to defend against it.

Fast-Moving Water With Heavy Debris

Floodwater filled with trees, rocks, soil, and debris is significantly more destructive than slow-moving water. This debris-laden water behaves more like wet concrete, exerting tremendous force that is difficult to resist.

When debris strikes flood barriers head-on, floating objects can act like battering rams, quickly overwhelming systems not designed for impact resistance.

Erosion Undermining Flood Defenses

Fast-moving water erodes soil beneath and around flood barriers. This erosion can cause levees and barriers to fail even if water levels do not overtop them. Homes built on erosive soils are particularly vulnerable when flood barriers lose their ground support. Always anticipate potential for erosion during a flood event.

Burn Scar Flooding

Wildfires in Washington, Oregon, and California have left large burn scar areas where vegetation no longer stabilizes soil. During heavy rain, these areas experience extreme runoff, sending debris, mud, and rocks into waterways—dramatically increasing flood damage potential downstream.

Flood Barriers That Can Be Ineffective in This Flood Environment

Water-Filled Flood Tubes (Diversion Tubes)

Water-filled flood tubes are most effective for shallow flooding of approximately one foot or less, particularly in stagnant water conditions. During recent flood events, concerns include:

· Vulnerability to puncture from debris

· Increased risk of rolling due to flood depth

· Under-seepage beneath the barrier, especially on soil or sand surfaces

Barriers That Could Float Away

A simple rule of thumb: if a flood barrier floats in a swimming pool, it can float away during a flood if water builds up on both sides of the barrier.

Continued rainfall, combined with seepage and runoff on the protected side, can cause buoyant flood barriers to lose stability and float away when exposed to fast-moving, deep floodwater.

Sandbags

Sandbags are labor-intensive, unstable at greater heights, and allow significant water seepage. Their lifespan is short, and they are typically only effective for minor flood events. West Coast watersheds often do not provide sufficient warning time to deploy sandbag defenses effectively.

Flood Barriers That Cannot Be Raised

Due to the unprecedented depth of floodwaters in this situation, many defenses were simply not tall enough. For most temporary flood barrier designs, height cannot be added once deployed.

Barriers that cannot be stacked or expanded offer limited protection when flood projections change. In contrast, some flood defenses were successfully expanded to achieve greater heights. If flood depths have the potential to increase unexpectedly, the ability to build upon an existing barrier is critical.

Flood Defense Systems Performing Best in the Current West Coast Flooding Environment

1. HESCO Barriers

HESCO barriers are widely used by government agencies across the United States due to their strength and adaptability.

Key advantages:

· Continuous, interconnected barrier design provides high structural strength

· Stackable to achieve significant protective heights

· Soil fill resists debris impact and heavier debris flows

· Extremely heavy and resistant to movement

· “Dirt-to-dirt” ground contact reduces under-seepage

· Long lifespan (typically used for extended or semi-permanent deployments)

· Cost-effective for large-scale, high-water protection

2. Geodesign Flood Barriers

Geodesign flood barriers are made from steel or aluminum and are designed for rapid deployment and high-impact resistance.

Key advantages:

· No fill material required and fast to deploy

· Sloped design deflects debris impact

· Fully reusable with long service life

· Flat-pack storage for efficient transport

· Excellent resistance to sliding on wet surfaces

· Do not float, even during overtopping

3. NOAQ Boxwall Flood Barriers

These flood barriers are not designed for debris impact but are widely popular because they are fast to deploy and relatively inexpensive. For residential flood protection where time is limited and there is no significant threats of debris impacts, this product is quite popular

Key advantages:

· No fill material required and fast to deploy

· Lightweight and easy to put together

· Fully reusable

· Stack up like a bunch of chairs for storage making them logistically friendly for transport and storage

NOTE: Anchor this product down by putting sandbags on the toe of the product if deploying it within a high wind environment

Key Takeaways and Suggestions for Homeowners Planning to Combat Floodwaters

· Understand historical flood levels and potential flood risks to determine minimum protection requirements

· Be aware of hazards or issues within flood situation like wave action, debris impact, high winds, and time constraints when selecting a barrier

· Compare available response time with deployment time for any flood barrier system to make sure you have time to deploy it

· Develop a real plan. Identify exactly what you need and what you need to do in order to accomplish your plan. It will save you precious time.

Once floodwater is visible, it is often too late to act. Having a well-defined plan can makes a critical difference when time is not a luxury!

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Flood Defense Group

www.flooddefensegroup.com