What they found was not hidden. It was happening in broad daylight, on public land, under contract, with county trucks and county workers and county-approved herbicide formulas. Orange County's Flood Control District had been spraying the banks of San Juan Creek — and dozens of other flood channels across the county — with an estimated 150,000 gallons of herbicide annually. Twice a year. Year after year. The chemicals: glyphosate (better known by the brand name Roundup), triclopyr, and imazapyr. The purpose: vegetation management, the institutional term for killing the plants that grow in and around flood channels to maintain water flow capacity.

The water flows to the beach. That part, apparently, was not factored in.

The System They Built

Orange County's flood infrastructure is a product of the mid-twentieth century, an era when the primary engineering objective was to move water off developed land as efficiently as possible. The county is heavily paved — decades of suburban expansion across once-permeable coastal plain — and when it rains, which it does in concentrated, intense events during winter months, enormous volumes of water race off rooftops, parking lots, streets, and manicured lawns and rush toward the ocean through a network of concrete channels. San Juan Creek is part of that network. It serves a genuine function: without it, flooding would damage property and endanger lives.

The problem is that this infrastructure was never designed with any consideration for what it carries chemically, or what happens when it arrives at the coast. The channels route water to the ocean, but they also route everything in the water — tire rubber, petroleum, nitrogen, sediment, and, since at least the 1990s, whatever herbicide formulation the county's vegetation management contractors happened to be using that season. The system treats the watershed as a drainage problem. It does not treat it as an ecosystem.

Over 8 tons of herbicide applied to San Juan Creek twice per year, according to data compiled by Creek Team OC from county records. Eight tons. Most Orange County residents had no idea this was occurring in their waterways, because no one had bothered to tell them — and no one had bothered to film it.

The Creek Team

Creek Team OC did not begin as an organization. It began as a group of people who noticed something, pulled out their phones, and started recording. In early 2026, they launched an Instagram account and began posting footage of county spray crews working the banks of local waterways — trucks, long hoses, chemical mist drifting across the channel and into the water. The videos were not dramatic in the staged sense. They were simply documentation: this is what is happening, here is where, here is when, here are the chemicals on the label.

The account attracted thousands of followers within weeks. The footage landed at a cultural moment when the conversation about what goes into Southern California's water — and what comes out at the coast — had become personal for a lot of people. Parents who let their kids play in the shorebreak at Doheny. Surfers who paddle out after rain and accept a certain baseline of risk they'd rather not think too hard about. Homeowners who live within a few hundred feet of a flood channel and had never seen it listed on any real estate disclosure.

The response from official California was unusually swift. The state's Department of Fish and Wildlife opened a formal investigation into potential violations of the Fish and Game Code in San Juan Creek. Under California law, the application of certain pesticides to waterways requires specific permits, and the discharge of substances harmful to fish and wildlife is a criminal offense. Whether the county's program crossed those legal lines is what the investigation was tasked with determining. In March 2026, before the investigation concluded, Orange County officials announced they would stop spraying herbicides in San Juan and Trabuco Creeks indefinitely. Roundup — glyphosate — had already been removed from those channels as of January 2025.

A concrete flood control channel of the type that lines Southern California's suburban watersheds. Built to move water, not to sustain it — and not designed for the chemical reality of modern vegetation management programs. — Pexels

What the Chemicals Do

Glyphosate is the most widely used herbicide on Earth. It works by blocking an enzyme called EPSPS, part of the shikimate pathway — a metabolic process present in plants, fungi, and bacteria, but not in animals. This is why its manufacturers have long argued it is selectively toxic: it kills what it targets and leaves vertebrates largely unharmed. But aquatic ecosystems are not composed primarily of vertebrates. The shikimate pathway is present in the algae and microorganisms that form the base of aquatic food webs. Glyphosate disrupts that base. Studies have documented its effects on the invertebrates, amphibians, and fish that depend on algal production for food and habitat. In waterways that lead directly to marine environments, those effects travel.

Triclopyr targets broadleaf plants and has been documented to affect aquatic invertebrates at concentrations that can occur following rainfall-driven channel flushing events. Imazapyr — the most persistent of the three — binds to soil and can remain biologically active in water for extended periods. Applied to the banks of a concrete channel that receives intense, rapid water flow during rain events, these compounds don't stay where they're put. They go where the water goes. And in Orange County, the water goes to the sea.

The downstream receiving environment — the nearshore zone at Doheny, at Salt Creek, at the breaks that sit at the mouths of these channels — is not a dead zone. It is a kelp-adjacent, biologically active stretch of Southern California coast that supports fish nurseries, invertebrate populations, and the broad marine ecosystem that the surfing community, the recreational fishing community, and the coastal tourism economy all depend on. What enters that environment in 150,000 gallons of annual herbicide application does not return to the spray truck.

Left: Every flood control channel in coastal California terminates at the ocean. What enters the channel enters the sea. Right: The warning embossed on storm drains across the U.S. — a reminder that these systems are connected, always, to the water people swim in. — Pexels

Nonpartisan Water

Orange County is not, historically, a place associated with environmental activism. It is one of the most reliably conservative counties in California — a region that has, for generations, been skeptical of regulatory overreach, protective of private property, and wary of the kind of coalition politics that tends to form around environmental causes. The Creek Team did not form along any of those lines. It formed because the people who live and surf and raise families near these waterways looked at what was going into them and decided they didn't want it there. Surfers. Parents. Homeowners. Neighbors. People who voted for different candidates and held different views about most things, united by the basic proposition that clean water is not a political position.

It shouldn't have required a social media campaign and a state investigation to produce a halt to a practice that a basic reading of the downstream geography should have flagged decades ago. The flood control infrastructure that serves Orange County was built with one objective, and that objective was never water quality. It was never ecological health. It was never the downstream effects on the coast or the nearshore environment or the people who use it. It was water velocity. Get the water to the ocean. Everything else was someone else's problem — until it became everyone's.

The county is now piloting a program of manual vegetation removal — labor-intensive, more expensive, and far more honest about what these channels actually are: living corridors connecting the mountains to the sea, not inert infrastructure. A formal water board permit for the revised program is expected in the summer of 2026. California's Department of Fish and Wildlife investigation remains open.

San Diego County, it's worth noting, does not manage its flood channels the same way. The contrast between adjacent counties using adjacent watersheds and arriving at dramatically different chemical approaches raises questions that extend far beyond Orange County. How many other flood control districts are running similar programs? How many channels draining to how many beaches are receiving how many gallons of which compounds, on which schedule, under which permits, with what downstream monitoring in place? These questions do not yet have comprehensive answers. In most places, no one has filed the public records requests. No one has launched the Instagram account. No one has been watching.

The Creek Team was watching. And the creek — which has been connecting these mountains to this ocean for ten thousand years, long before the concrete was poured and the spray trucks were dispatched — is still there, still running, still looking for a way through.