Mexicali Municipality in the context of Mudflat

The Colorado River Delta is the region where the Colorado River once flowed into the Gulf of California (also known as the Sea of Cortez) in eastern Mexicali Municipality in the north of the state of Baja California, in northwestern Mexico. The delta is part of a larger geologic region called the Salton Trough. Historically, the interaction of the river's flow and the ocean's tide created a dynamic environment, supporting freshwater, brackish, and saltwater species. Within the delta region, the river split into multiple braided channels and formed a complex estuary and terrestrial ecosystems. The use of water upstream and the accompanying reduction of freshwater flow has resulted in the loss of most of the wetlands of the area, as well as drastic changes to the aquatic ecosystems - an ecosystem collapse.

Mexicali (English: /ˌmɛksɪˈkæli/; Spanish: [mexiˈkali] ) is the capital city of the Mexican state of Baja California. The city, which abuts the Mexico–United States border and the U.S. city of Calexico, California, is the seat of the Mexicali Municipality. It has a population of 689,775, according to the 2010 census, while the Calexico–Mexicali metropolitan area is home to combined 1,000,000. Mexicali is a regional economic and cultural hub for the border region of The Californias.

Mexicali was founded at the turn of the 20th century, when the region's agricultural economy experienced a period of boom. The city rapidly expanded throughout the 20th century, owing to the proliferation of maquiladoras in the city, making the Mexicali economy more interconnected with businesses from across the border. Today, Mexicali is a major manufacturing center and an emerging tourist destination.