The Merced River is protected under the National Wild and Scenic Act. It is free flowing until Lake McClure and tends to flood in the winter and spring, and then reduce to a mere trickle in the late summer and fall. Highway 140 runs along part of the Merced River and is the main road into Yosemite National Park. Numerous recreational opportunities are available along the Merced River including fishing, kayaking, whitewater rafting, camping, hiking, swimming, and picnic areas.
Much of the length of the river has been "improved", to facilitate fish spawning.
A map of the Merced River watershed and Merced Irrigation District canals is available at: http://www.mercedid.org/_images/watershed_map.pdf . This map shows the irrigation district's main canals; it does not show the small canals and pipelines that serve most farms. The map also shows creeks that collect stormwater runoff.
Towns along the Merced River include:
If the Merced River took the most direct path to the San Joaquin River, it would follow Bear Creek through mostly-clay soils.
The Ice Ages severely affected the Merced River. A glacier carved out the Yosemite Valley, grinding mountains into sand. Half Dome and El Capitan are remnants of those mountains. Since the Ice Ages, the Merced River has flowed past Livingston, leaving sandy soil in its wake.