Chowchilla River - Lower River

Lower River

Seven miles downstream of Eastman Lake, the Chowchilla's water is diverted into both the Berenda and Ash sloughs, with excess water continuing down the main river channel. The river flows west-southwest for most of the rest of the journey before flowing west in the last few miles. The last 2 mi (3.2 km) of the river doubles as an irrigation canal for farms located along its banks.

The main river channel ends abruptly about 3 mi (4.8 km) east of the San Joaquin River. The river has never had a defined natural outlet to the San Joaquin, as evidenced by the fact that the riverbed shrinks considerably in size as it travels west. A natural outlet never existed because the river only has a seasonal flow, and natural water flow would normally dry up before it had a chance to reach the San Joaquin. In rare years of torrential rains, there would still be water in the river at the end of the riverbed, at which point the water would simply flood the area past the end of the riverbed. Those floodwaters would eventually find their way into the San Joaquin River.

As part of the Lower San Joaquin River Flood Control Project, a diversion canal was built to connect the end of the riverbed with the Eastside Bypass, allowing the Chowchilla's water a controlled outlet to the San Joaquin River during years of heavy rains.

The Chowchilla River serves at the outlet of the Madera Canal.