In 1849, about 35,000 Native Americans, Mexicans and Yankee frontiersmen lived in the natural wilderness of California. Then someone whispered “gold” and more than 100,000 prospectors poured in, some from as far away as China. They shared one ambition: to sieve a fortune out of the heart of the Sierra Nevada mountains. At first the prospectors were comrades in a great adventure, all bound to strike it lucky. Soon, however, things went sour.

Native Americans were the first victims, ousted from the land where they had lived for maybe 10,000 years. Many died from diseases such as malaria that travelled with the grasping “fortyniners”. Eventually all “non-Americans” shared their fate, chased out of paradise by vigilantes desperate to pocket the wealth. “True” Americans also suffered. Lawless, jerry-built towns were frequently burnt down. Diseases like cholera and dysentery were rife. Most were exhausted, homesick and still poor. Of the original “fortyniners”, 30 per cent are thought to have died as a result of illness, accident or violence.

During the mid-1850s, new mining corporations arrived and began hydraulic mining. Jets of water were blasted into rivers and hillsides by high-pressure hoses, so powerful they could kill someone standing 60 metres away. By the 1870s, a single hose could squirt out up to 25 million gallons (more than 113 million litres) of water in 24 hours.

The result was to change California’s landscape forever. Rivers and streams became choked with debris and flooded, or were dammed, drained and rerouted. There was so much detritus in the Feather and Yuba that the river beds were higher than the streets of the town where they converged. Fishing grounds were ruined. Mud, sand and gravel washed out over acres of arable land, killing cattle and destroying houses. Hillsides and forests were laid bare and mercury used by the miners still contaminates the fish today.

By the 1860s, it was clear hydraulic mining was turning a wilderness into a wasteland. It took another 20 years to stop the blasting.