After gold was discovered in 1848, around 300,000 people came to California from all over the world, and the Sacramento and San Joaquin rivers became highways to the gold country. Fleets of sailing ships and steamboats carried people and supplies from San Fransisco to Sacramento, and many of these ships docked at the new settlement of Brazos del Rio. Renamed Rio Vista in 1860, the town supported a burgeoning commercial trade for local settlements. Settlers soon found that the Delta's rich peat soil was as valuable for growing crops as gold was, leading to settlements on the river's natural levees and efforts to reclaim tidal marsh for agriculture. Shipping on the Delta eventually declined because of the railroad and because waterways became choked with mud and debris from hydraulic mining operations upstream. Scow schooners like Alma had flat-bottomed hulls designed to navigate the Delta's shallow waters and to rest on the bottom at low tide.