The lake and shoreline wetlands are a critical staging area along the North American Pacific Flyway. During peak migration, as many as 1.5 million shoreline birds have stopped at the lake. The Great Salt Lake also is an important economic driver, contributing approximately $1.3 billion to the Utah annual gross domestic product through aquaculture, recreation, and industrial activities such as mineral extraction and processing.

In 1959, a rock-fill railroad causeway was constructed across the middle of the Great Salt Lake. The construction of the causeway divided the lake into two parts; the north (Gunnison Bay) and the south (Gilbert Bay). Some water is conveyed through the causeway via engineered openings and the causeway material, depending on permeability. Because the south part of the lake receives almost all freshwater inflows, the salinity of Gunnison Bay is greater than the salinity of Gilbert Bay. Owing to its lower salinity, Gilbert Bay supports an ecosystem rich with brine shrimp and brine flies that attract millions of migratory birds and waterfowl as they travel the Central Flyway.