Walk down to the shoreline in Long Beach after a heavy rain and you’ll see it. That distinct, dark plume of water pushing out from the concrete mouths of the L.A. River and the San Gabriel River. It's the channel water Long Beach residents have been side-eyeing for decades. People call it "the soup." Some call it a disaster. Honestly, if you grew up here, you were probably told never to touch the water for at least 72 hours after a storm. But there is a lot more to the story of our urban runoff than just "it's dirty." We’re looking at a massive, complex engineering legacy that dictates how millions of gallons of water move through our city every single day.
It's a weird vibe. You’ve got these beautiful, multi-million dollar homes in the Peninsula and Naples, literally feet away from channels that act as the primary drainage pipes for the entire Los Angeles Basin.
The Reality of Channel Water Long Beach and Where It Comes From
Most people think the water in the channels is just "ocean water" that got stuck. Nope. Not even close. The channel water Long Beach deals with is primarily a cocktail of treated wastewater, urban runoff, and, during the winter, massive amounts of storm surge.
The two big players are the Los Angeles River and the San Gabriel River.
The L.A. River isn't really a "river" in the traditional sense anymore; it’s a 51-mile concrete flood control channel. When it rains in the San Fernando Valley, that water picks up everything—brake dust, nitrogen from lawns, dropped burritos, you name it—and shoots it down to the Long Beach harbor at high speeds. Because the river is paved, the water can't soak into the ground. It just gains momentum. By the time it hits the Pacific near the Queen Mary, it’s carrying the debris of a thousand neighborhoods.
Then you have the San Gabriel River on the east side. It's a bit different because of the power plants. The Haynes Generating Station and the AES Alamitos plant use that channel water for cooling. This creates a "warm water jetty" effect. If you’ve ever wondered why sea turtles—specifically Green Sea Turtles—hang out in a concrete channel in an industrial part of SoCal, that’s why. The water is artificially warm. It’s a bizarre ecosystem where nature has basically forced itself into an industrial gap.
Why the Breakwater Makes Everything Stick Around
The biggest gripe anyone has with channel water Long Beach isn't just the water itself; it's the fact that it doesn't go anywhere.
In any other coastal city, the tide would pull that runoff out to sea. But Long Beach has the Long Beach Breakwater. Built decades ago to protect the U.S. Navy fleet (which is long gone), this massive rock wall kills the wave action. No waves mean no circulation.
The water just... sits.
It stagnates.
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When the river sends trash and bacteria into the harbor, the breakwater acts like a giant bowl, keeping the pollutants trapped right against the beaches where people want to kiteboard or swim. This is why Long Beach often gets "F" grades on beach report cards from organizations like Heal the Bay, even when neighboring Seal Beach or Huntington Beach get "As." It’s not that Long Beach is inherently dirtier; it’s that our geography is currently rigged against us.
Breaking Down the Bacteria: Is It Actually Dangerous?
Let's get real about the health risks. We’re mostly talking about Enterococcus and fecal coliform.
Sounds gross? It is.
But it’s important to understand the nuance. On a sunny day in July, after weeks of no rain, the channel water Long Beach provides is often perfectly safe for a dip. The sun’s UV rays are surprisingly good at killing bacteria. The city’s Health Department monitors the water constantly. They use the state-mandated standards to post those yellow signs.
The problem is the "First Flush."
That’s the first big rain of the season. It’s basically a giant power-wash of every street in L.A. County. The bacterial counts during a First Flush are astronomical. We’re talking thousands of times higher than the safety limit. If you swim in that, you’re looking at ear infections, skin rashes, or the dreaded "stomach flu" symptoms.
The Trash Problem is Actually Improving
You might remember the 90s when the mouth of the L.A. River looked like a literal landfill. It was embarrassing.
Things have changed, mostly because of "Total Maximum Daily Loads" (TMDLs). These are legal limits on how much trash a city can let flow into the water. If they exceed it, they get fined. Heavily.
Today, there are massive trash booms. These are floating barriers across the channels that catch the big stuff—Styrofoam cups, plastic bags, soccer balls.
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Is it perfect? No.
Microplastics are still a nightmare. But if you compare the channel water Long Beach sees today to what it saw thirty years ago, the visible pollution is significantly lower. We’re seeing more wildlife return. It's common to see herons, egrets, and even the occasional sea lion hunting in the channels now. They wouldn't be there if the water was as toxic as the urban legends suggest.
The Future: Will We Ever Tear Down the Breakwater?
This is the billion-dollar question.
For years, groups like Sinking the Breakwater have campaigned to have parts of the wall removed. The logic is simple: bring back the waves, flush out the channel water, and clean up the beach.
It sounds like a no-brainer until you look at the economics.
The Port of Long Beach is one of the busiest in the world. Without that breakwater, the surge could make it difficult for massive container ships to dock. Then there are the homeowners. If you live on the sand in the Peninsula, you probably don't want 6-foot swells hitting your front porch. The breakwater protects the property values from coastal erosion.
The Army Corps of Engineers did a massive study on this recently. Their conclusion? Removing the breakwater is technically possible but incredibly expensive and carries risks for the port. So, for now, we are stuck with the water we have.
How to Actually Navigate Long Beach Water Safely
If you live here or you’re visiting, you don't need to be terrified of the water. You just need to be smart.
The 72-Hour Rule is Law. Never, ever go into the water within three days of a rainstorm. This includes the Colorado Lagoon and the Alamitos Bay. The runoff needs time to disperse.
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Check the Beach Report Card. Don't guess. Heal the Bay publishes a weekly report card. If Alamitos Bay is an "A" and the L.A. River mouth is an "F," stay in the bay.
Avoid the River Mouths. The worst of the channel water Long Beach deals with is always concentrated at the ends of the concrete channels. The further you move away from the L.A. River (towards the East Side and Belmont Shore), the better the water quality usually gets.
Watch the Tide. An incoming tide brings in fresh, clean seawater from the open ocean. An outgoing tide pulls the channel water out toward the harbor. If you’re going to swim, do it when the tide is coming in.
Actionable Steps for Improving the Water
Change isn't just up to the Army Corps of Engineers or the City Council.
The water in the channels starts at your front door. Literally. When you over-water your lawn and the excess runs into the gutter, it carries fertilizers straight to the San Gabriel River. When people don't pick up after their dogs, that bacteria ends up at the Long Beach shoreline.
Consider installing a rain barrel. It catches the water before it hits the street. Or, better yet, replace a patch of grass with California native plants. These have deep roots that help soak up water, preventing it from ever becoming "runoff."
The channel water Long Beach navigates is a reflection of the entire 4,000-square-mile watershed. We are the end of the line. Everything everyone does "upstream" ends up on our sand.
Understanding that this water isn't just a mystery sludge—but a direct result of urban design—is the first step in fixing it. We’ve managed to bring the sea turtles back. We’ve managed to catch the floating trash. The next step is a long-term fix for the circulation and the bacterial load. It's a slow process, but for a city that lives and breathes by its coastline, it's the only path forward.
Stay informed by checking the Long Beach Department of Health and Human Services website for real-time water quality closures. If you want to get your hands dirty, join a local beach cleanup at Rosie's Dog Beach. Seeing exactly what washes up after a storm is the fastest way to understand why protecting our channels matters.