An engineering mistake in 1905 accidentally created California’s largest lake — and it changed the desert forever

More than a century ago, an engineering mistake in the California desert unleashed the Colorado River into a vast depression below sea level. The result was a lake that was never supposed to exist — the Salton Sea, now California’s largest lake by surface area.

The strange story began in 1905, when engineers were trying to make the dry Imperial Valley suitable for farming.

The California Development Company had constructed an irrigation canal to divert water from the Colorado River to the growing agricultural region. But the river was running unusually high, and the canal could not contain it.


The Colorado River eventually broke through the canal’s headworks and began pouring into the low-lying Salton Sink, a natural basin more than 200 feet below sea level.

What started as an attempt to control water quickly turned into a massive flood.

For almost two years, the Colorado River continued flowing into the basin. Temporary efforts to stop the breach repeatedly failed, and the floodwaters spread across farmland, settlements and infrastructure in southeastern California.

The Southern Pacific Railroad was also threatened as the rising water approached its tracks. Historical accounts describe enormous emergency efforts to protect the railroad and prevent the flooding from completely cutting its route.

But the most extraordinary consequence came after the flooding stopped.

The water didn't simply drain away.

The Salton Sink was a closed basin with no natural outlet to the sea. As a result, much of the water remained trapped there, creating what became known as the Salton Sea.

The US Geological Survey says the lake sits at California's lowest elevation, roughly 235 feet (72 metres) below sea level.

For decades, irrigation runoff from the Imperial and Coachella valleys helped keep the lake filled. At its height, the Salton Sea became far more than an accidental lake.

In the 1950s and 1960s, it was promoted as a glamorous desert vacation destination. Marinas, yacht clubs, fishing spots and resorts attracted visitors, while celebrities and developers helped fuel dreams of turning the area into a major California resort.

But the lake had a fundamental problem: it had nowhere to drain.

Water evaporates, but the minerals and salts dissolved in it remain behind. Over time, salinity increased, contributing to the decline of the recreational boom.

Today, the Salton Sea is a very different place. Yet it remains ecologically important because it sits along the Pacific Flyway, one of North America's major migratory routes. Birds use the lake and surrounding wetlands as an important stopover and habitat.

The lake is also facing another threat. Reduced inflows from the Colorado River have contributed to falling water levels, exposing more lakebed. As the shoreline retreats, concerns have grown about dust from the increasingly dry lakebed.

The Salton Sea, in other words, is the legacy of an engineering project that went spectacularly wrong.

A canal designed to bring water to California's farms accidentally created a lake that has survived for more than a century — and permanently transformed the desert around it.