The City of Oceanside is home to a variety of waterbodies, such as rivers, creeks, lakes, lagoons, and the Pacific Ocean. The climate and proximity to the ocean makes Oceanside an important place for aquatic habitat. Oceanside waterbodies are also popular destinations for outdoor enthusiasts.

Every Oceanside waterbody is part of watershed. A watershed is an area of land that drains water to the nearest river, creek, lake, lagoon or ocean.  In fact, everyone lives in a watershed. 

Watersheds are usually bordered by land areas of higher elevation that drain rainwater to areas of lower elevation. As water travels downhill, it cuts into the earth creating a river, creek, or stream, depending on the amount of water. These waterways connect together to form a network that ultimately transports water into a lake, lagoon or ocean. 

Watersheds do not follow political boundaries; therefore, many cities or other jurisdictions are part of multiple watersheds. The City of Oceanside has two watersheds in its city limits: the San Luis Rey Watershed and the Carlsbad Watershed.

Because watersheds are all around us, many of the activities we do at home and at work can affect the water quality of our watersheds. For instance, washing your car in the driveway allows soaps, grit, grime, metals, and bacteria to enter a storm drain and eventually flow into waterbodies. Additionally, commercial businesses that store oil-leaking equipment outside can pollute our waterbodies when rain washes that oil into the nearest waterbody. Everyone can help protect the quality of water in Oceanside waterbodies by their chosen activities. 

To learn how you can help prevent water pollution, visit the Residential and Industrial/Commercial pages on this website. It is up to all of us to help protect the water quality of Oceanside’s watersheds for our families and our community.  Since watersheds are all around us, everyone plays a role in keeping them clean and beautiful.   

San Luis Rey 

The San Luis Rey (SLR) River originates in the Palomar and Hot Springs Mountains in eastern San Diego County and extends over 55 miles across northern San Diego County before discharging to the Pacific Ocean in the City of Oceanside. The SLR River parallels Highway 76 in Oceanside. The SLR River drains a watershed of approximately 360,000 acres or 562 square miles. Within the City of Oceanside, the SLR River is fed by one of its tributaries, Pilgrim Creek. 

There are numerous land use types within the watershed with the majority of land remaining undeveloped. Higher population concentrations are in the western area of the watershed. Residential and agriculture serve as the dominant land uses in the watershed. 

About 10% of the City of Oceanside’s drinking water supply comes from Oceanside’s Mission Basin Groundwater Purification Facility (MBGPF). This facility treats brackish groundwater from wells located in the San Luis Rey River valley. The groundwater is purified by reverse osmosis and then disinfected. 

Recreational Activities: Fishing, swimming, walking, biking, bird watching.  

Public Access: The San Luis Rey River Trail is open to bicyclists and pedestrians and stretches nine miles along the river. Visit the Parks & Recreation webpage for more information. The mouth of the river is easily accessible where the SLR River enters the Pacific Ocean. 

Loma Alta Creek/Slough 

 Loma Alta Creek flows parallel to Oceanside Boulevard, and the Loma Alta Slough is located north of Buccaneer Beach Park. Loma Alta Creek is just over seven miles long and drains nearly 6,300 acres of land. The Slough is a coastal estuarine wetland. Loma Alta Watershed is the northernmost watershed in the greater Carlsbad Watershed. 

The only named tributary is Garrison Creek which parallels Mesa Drive west of El Camino Real. Much of the creek has been modified throughout the years, with the use of fully or partially concrete-lined channels to stabilize the creek-bed slopes.

Recreational Activities: Fishing, walking, biking, bird watching, picnicking. 

Public Access: Loma Alta Slough is accessible from Buccaneer Beach Park located on Pacific Street just north of Morse Street. From the parking lot there is a short walking path along Loma Alta Slough and Creek. The Garrison Creek Nature Trail is a mile long trail with educational signs, for more information visit the Parks & Recreation webpage.  

Buena Vista Creek/Lagoon 

The Buena Vista Watershed extends approximately 10.6 miles inland from the coast, approximately 14,400 acres in area. The Watershed begins on the western slopes of the San Marcos Mountains, where surface runoff collects to form Buena Vista Creek. The creek weaves its way west to the Pacific Ocean, forming a lagoon at its mouth. 

In the City of Oceanside, Buena Vista Creek parallels Highway 78.Large sections of Buena Vista Creek have been concrete-channelized to reduce the chance of flooding private property. 

Approximately 87% of the Watershed is developed, primarily with commercial and residential land uses. Some agricultural activities still exist in the watershed. All of these land uses are potential sources of pollutants. The watershed provides refuge for a wide array of wildlife, endangered, and California Species of Concern, such as the California Gnatcatcher, Least Bell’s Vireo, Orange-throated Whiptail and the Yellow-breasted Chat. 

A weir at the mouth of the lagoon excludes tidal influence, making Buena Vista Lagoon the only freshwater lagoon in Southern California. Numerous migratory waterfowl and shorebirds can be seen and there is good fishing (with a license) from shoreline access points. 

Recreational Activities: Fishing, bird watching. 

Public Access: Access to Buena Vista Creek is limited. The Lagoon can be accessed via the Buena Vista Audubon Society facility at 2202 S Coast Highway and across the street there is a short walking path along the Lagoon. It can also be accessed via Lagoon View Drive. 

Calavera Creek/ Agua Hedionda Creek 

Calavera Creek is located in the southeastern corner of Oceanside near Lake Boulevard and travels through Oak Riparian Park. Calavera Creek is a tributary to Agua Hedionda Creek that opens up into a lagoon near the Pacific Ocean.  

Along the banks of Calavera Creek in the City of Oceanside is extensive growth of cattails, bulrush, coast live oak, chaparral, and arroyo willows. No endangered species have been identified within the area of Calavera Creek that flows through Oceanside. However, as a whole, Calavera Creek does serve as a wildlife corridor for migratory species. 

Recreational Activities: Picnicking, walking, biking, bird watching 

Public Access: From Oak Riparian Park located off of Lake Boulevard near Ridge Road. Lake Calavera Trails located in Carlsbad are accessible from multiple locations in Oceanside, contact the City of Carlsbad for more information.  

Guajome Lake 

Located in the far eastern edge of Oceanside lies Guajome Lake, a County of San Diego-managed water body that is part of Guajome Regional Park. This 12-acre lake is within the San Luis Rey Watershed.  

Guajome Lake is surrounded by marsh and riparian habitats that support various types of plant species. Over 180 bird species have been observed in the park including a few endangered bird species: the California Least Tern and the Light-Footed Clapper Rail. 

Recreational activities:  Fishing, camping, picnicking, hiking, and biking. Two-day use areas have playgrounds, a basketball court and lawns for picnicking and relaxing. 

Public Access: The Park is accessible from the north off of Guajome Lake Road and from the south off of North Santa Fe Avenue. 

Talone Lake 

Situated between Frazee Road and College Boulevard, behind the Town Center North Shopping Area lies Talone Lake, a 23-acre lake surrounded by isolated wetland ponds. Located in the San Luis Rey Watershed, Talone Lake has become an important habitat refuge for migrating wildlife. Created by a natural depression in the land, Talone Lake’s water is recharged primarily by urban runoff and rainfall. 

 Patches of isolated wetlands primarily house woodland and riparian scrub species. In the interior portions of the Lake, bulrush continues to grow rapidly, naturally depleting Talone Lake’s water level. Least Bells Vireo and California Gnatcatcher are the two primary endangered species sighted in the Talone Lake area. 

Talone Lake does not support recreational uses by humans. It has been preserved to solely function as a wildlife habitat for flora and fauna. 

Recreational Activities: None 

Public Access: None 

Foss Lake 

Located in the northeastern portion of Oceanside, along Douglas Drive, lies a very sensitive and unique wetland habitat called Foss Lake. Approximately 75 acres in size, Foss Lake is one of the only inland alkali marshes in San Diego County. 

Over the years Foss Lake has been altered in various ways. Approximately 50 years ago the area was filled and used as an agricultural site supporting crops and cattle. The construction of Douglas Drive divided Foss Lake into two sections, a parcel north of Douglas Drive and a parcel south of Douglas Drive. The southern parcel underwent a habitat management project to remove invasive plant species and allow the multitude of sensitive and endangered native vegetation, such as the Diegan coastal sage and Southern willow scrubs, to flourish. 

Foss Lake supports an array of wildlife including the endangered Least Bells Vireo, Yellow-breasted Chat, and threatened California Gnatcatcher. 

As part of the San Luis Rey Watershed, Foss Lake has been preserved as an open space biological reserve and is currently under the management of the Center for Natural Lands Management. 

Foss Lake does not support recreational uses by humans. No boating, biking, or motorized vehicles are permitted on the premises. 

Recreational Activities: None 

Public Access: None 

Whelan Lake 

Located in the San Luis Rey Watershed on the northern end of the City of Oceanside lies a 73-acre bird sanctuary called Whelan Lake. Bordered by Camp Pendleton and adjacent to the City of Oceanside San Luis Rey Wastewater Treatment Plant. 

 Whelan Lake is a man-made body of water that was used in a dairy farm operation owned by the Whelan Family. Ellen Whelan, upon her death in 1985, donated the entire 305-acre property to a Board of Trustees with the understanding that the land was to remain protected and used as a sanctuary for migratory and resident waterfowl. 

The water table in Whelan Lake is fed by tertiary-treated effluent from the San Luis Rey Wastewater Treatment Plant. Tertiary-treated waters, high in nutrients, help promote the growth and sustainability of the many species of plant life. Grassland habitat predominately characterizes the area around the Lake. However, some scrub and chaparral habitats can also be found. 

Volunteers from Buena Vista Audubon Society conduct a monthly count of the bird species to be found at Whelan Lake. To date, 170 species of birds have been sighted there, including Canadian Geese, Willow Flycatcher, Least Bell’s Vireo, White Pelicans, and 15 different duck species including Wood Ducks. 

Whelan Lake is not open to the public except by contacting the Whelan Lake caretaker at 760-722-4887 to schedule an appointment or by attending the Whelan Lake Bird Sanctuary Walk every first Saturday of the month, visit the Buena Vista Audubon’s website for more details. The lake has been preserved to function solely as a sanctuary for resident and migratory waterfowl. 

Recreational Activities: Bird Watching 

Public Access: Contact the Whelan Lake caretaker at 760-722-4887 to schedule an appointment or attend the Whelan Lake Bird Sanctuary Walk every first Saturday of the month, visit the Buena Vista Audubon’s website for more details. 

Pacific Ocean 

The world’s largest body of water, the Pacific Ocean, covers about one third of the Earth’s surface. It is also an integral part to the culture and lifestyle of Oceanside. Additionally, all Oceanside waterbodies drain to the Pacific Ocean.  

Recreational Activities: Fishing, swimming, surfing, walking, biking, boating, bird watching. 

Public Access: Multiple access points from Pacific Street, The Strand and the Harbor. 

Report any water running in the street when it is not raining or someone dumping something in the storm drain or curb and gutter by calling Customer Care at (760) 435-4500.

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