The California Gold Rush started when gold was discovered at Sutter's Mill, one of Sutter, Sr.'s assets in the city of Coloma in 1848; the arrival of prospectors in droves ruined Sutter's New Helvetia and trade began to develop around a wharf he had established where the American and Sacramento Rivers joined. In the region where Sutter had planned to establish the city of Sutterville, Sacramento City was founded; Sutter, Sr. put his son in charge in frustration, and Sutter, Jr. worked to organize the city in its growth. However, its location caused the city to periodically fill with water. Fires would also sweep through the city. To resolve the problems, the city worked to raise the sidewalks and buildings and began to replace wooden structures with more resilient materials, like brick and stone. The city was selected as the state capital in 1854 after Mariano Guadalupe Vallejo failed to convince the state government to remain in the city of his namesake.