Sand Canyon Wash is an approximately 6.9 miles (11.1 km) (to its longest source) tributary of San Diego Creek

San Diego Creek

San Diego Creek is a waterway flowing into Upper Newport Bay in central Orange County in the U.S. state of California. Its basin covers in parts of eight cities, including Irvine, Tustin, and Costa Mesa. The major tributary of the northeast-flowing stream is Peters Canyon Wash, which joins a few...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of California

California

California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...

. Its headwaters rise in the northern San Joaquin Hills

San Joaquin Hills

The San Joaquin Hills are a set of low hills in coastal Orange County, California. They extend in a northwest-southeast direction, starting in the northwest in Newport Beach at the southern edge of the Los Angeles Basin, and extending southeast to San Juan Capistrano.-Geography and habitats:Named...

 as two streams, Shady Canyon Creek and Bommer Canyon Creek, then northwest into Sand Canyon Reservoir, formed by a dam across Strawberry Valley east of the community of Turtle Rock

Turtle Rock, Irvine, California

Turtle Rock is a neighborhood in the south part of Irvine, Orange County, California near Concordia University, Irvine and the University of California, Irvine. It is bounded to the north by University Drive and Mason Regional Park, to the east by the Strawberry Farms Golf Club and Ridgeline Drive,...

. The dry creek bed continues northwest from the reservoir, turning west where it enters the city of Irvine

Irvine, California

Irvine is a suburban incorporated city in Orange County, California, United States. It is a planned city, mainly developed by the Irvine Company since the 1960s. Formally incorporated on December 28, 1971, the city has a population of 212,375 as of the 2010 census. However, the California...

, flowing along the northeastern boundary of William R. Mason Regional Park

William R. Mason Regional Park

William R. Mason Regional Park, or as it is more commonly referred to, Mason Park, is a park in southern Irvine, California. It is one of the largest parks in Irvine and is traversed by trails.-Background:...

. The creek then turns west to empty into San Diego Creek in its San Joaquin Marsh section, about 2 miles (3.2 km) above where the larger creek enters Upper Newport Bay

Upper Newport Bay

The Upper Newport Bay is a large coastal wetland in Southern California and a major stopover for birds. Dozens of species, including endangered ones, can be observed here. Upper Newport Bay Nature Preserve and Ecological Reserve represent approximately 1,000 acres of open space...

.