San Gregorio Creek facts for kids

Quick facts for kids San Gregorio Creek
San Gregorio State Beach
Other name(s)	Arroyo de San Gregorio, Arroyo Rodrigues
Country	United States
State	California
Region	Santa Mateo County
Physical characteristics
Main source	Confluence of La Honda Creek and Alpine Creek in the Santa Cruz Mountains
River mouth	Pacific Ocean San Gregorio, California 0 ft (0 m) 37°18′36″N 122°16′37″W / 37.31000°N 122.27694°W / 37.31000; -122.27694
Basin features
Tributaries	Left: Alpine Creek Right: La Honda Creek, Harrington Creek, Bogess Creek, El Corte de Madera Creek, Clear Creek, Coyote Creek

San Gregorio Creek is a river in San Mateo County, California. Its name means Saint Gregory in Spanish. The river starts in the Santa Cruz Mountains. It flows southwest through forests and canyons.

The main part of San Gregorio Creek begins where two smaller creeks, Alpine and La Honda, meet. From there, it flows about 12 miles (19 km) through grassy areas. Finally, it reaches the Pacific Ocean at San Gregorio State Beach. Along its way, the creek passes through small towns like La Honda and San Gregorio.

History of San Gregorio Creek

San Gregorio Creek has an interesting history. In 1769, a Spanish explorer named Gaspar de Portolá camped here. He was on an expedition and accidentally went past his goal, which was Monterey Bay. He continued north and discovered San Francisco Bay.

The campsite at San Gregorio Creek is now a special historical spot. It is known as California Historical Landmark 26. In Spanish times, the creek was called Arroyo de San Gregorio. Later, in the 1850s, it was sometimes called Arroyo Rodrigues.

The San Gregorio Creek Watershed

A watershed is an area of land where all the water drains into a single river or creek. The San Gregorio watershed is about 11 miles (18 km) south of Half Moon Bay. It covers about 61 square miles (160 km²) of land. This makes it the second largest watershed along the coast in San Mateo County.

The watershed has about 45 miles (72 km) of streams that flow all year round. The main part of San Gregorio Creek starts where Alpine Creek and La Honda Creek join together in La Honda. It then flows for about 11.8 miles (19.0 km) until it reaches the ocean at San Gregorio State Beach.

The creek forms a small lagoon near the ocean, just upstream from the Highway 1 Bridge. This lagoon can be up to 5 acres (2.0 ha) big and 6 feet (1.8 m) deep. It is an important home for small fish like the tidewater goby. It also helps young steelhead grow. Young Coho salmon use the lagoon to get ready for their journey to the ocean.

Sometimes, the river can flood, especially during heavy rains. A famous flood happened in 1997 during an El Niño event.

Animals and Plants of San Gregorio Creek

The San Gregorio Creek and its smaller streams are very important for fish. These streams include La Honda, Alpine, Harrington, El Corte de Madera, and Bogess Creek. They provide about 33 miles (53 km) of places for young coho salmon to live and grow.

In the 1800s, there were so many salmon in the creek that people could catch them for sale. Coho salmon in this area are now considered an endangered species. This means their numbers are very low. Experts want to help these salmon recover. San Gregorio Creek is a top place to help bring coho salmon back.

Steelhead trout also live in San Gregorio Creek. In 1971, about 1,000 steelhead fish lived here. The California Department of Fish and Game is working to help both salmon and steelhead in this watershed.

However, there are some challenges for the fish. Roads and bridges, especially along Highway 84, can block fish from moving freely. Also, dirt and mud from building homes, grazing animals, and logging can harm the creek. Some pipes under roads completely block fish from passing through.

Besides fish, other special animals live here. These include the California red-legged frog.

Many unique plants also grow in the area. These include Western leatherwood, Santa Cruz manzanita, and King’s Mountain manzanita. These plants are considered rare or endangered in California. You can find them in places like the La Honda Creek Open Space Preserve.

Tributaries of San Gregorio Creek

A tributary is a smaller stream or river that flows into a larger one. Here are some of the creeks that flow into San Gregorio Creek, listed from the mouth (where it meets the ocean) to the head (where it starts):

• Palmer Gulch
• Coyote Creek
• Clear Creek
• El Corte de Madera Creek
  • Pine Tree Gulch
• Bogess Creek
• Kingston Creek (on the left side)
• Harrington Creek
• La Honda Creek
  • Woodhams Creek
  • Langley Creek
  • Woodruff Creek
  • Weeks Creek
    • Spanish Ranch Creek
• Alpine Creek
  • Mindego Creek
  • Rodgers Gulch