Until the middle of the past century, the San Diego River flowed into a large wetland that encompassed parts of San Diego Bay as well as Mission Bay. However, periodic flooding deposited large amounts of silt and debris into San Diego Bay. To prevent the silting and control the river, the Army Corp of Engineers built rock-faced dikes on both sides of the river about 250 feet apart that channel the water directly into the ocean. However, as nature always finds a way around what humans build, the river has created an estuary that is home to numerous birds, fish, and invertebrates.
Paved trails along the top of both dikes now serve as easy paths for walkers, bird-watchers, and bicyclists. The trail on the south side is very close to I-8 and visitors may find the traffic noise disconcerting. The south trail goes all the way to the ocean, ending at Dog Beach.
Of the two trails, the north trail is best for bird-watching as it will put visitors closest to the water. However, it is parallel to Sea World Drive, which can be noisy on weekends. The part designated the Southern Wildlife Preserve begins just west of where I-5 crosses the river and continues for a little over a mile to the West Mission Bay bridge. The bicycle trail continues for another 0.75 mile to Quivira Basin and the Mission Bay inlet. Also along the west end of the north trail, the San Diego River Park Foundation has posted a number of paintings from the 2015 “River Kids Discovery Days.” The paintings detail life along the estuary and are an inspiration for continued environmental education.
Regardless of which trail visitors decide to take, binoculars are a must for spotting all but the largest birds, as going down the bank to the estuary is not permitted. Signs are posted instructing visitors to stay on the trail and off sensitive habitat. This is especially true for the west end of the north trail, which is posted as a least tern nesting area. As part of the Pacific Flyway, many migratory birds stop along the San Diego River on their way south. Species that have been observed include pied-billed grebes, western grebes, northern pintail ducks, buffleheads, and red-breasted mergansers. In addition to the migratory birds, cormorants, ospreys, snowy egrets, great egrets, and various species of ducks can be observed here year around. Spring, summer, or winter — any season is a great one to take a walk along the estuary.
San Diego River Park Estuary Trails
Distance from downtown San Diego: approximately 9 miles. Allow 15 minutes driving time. To reach the North Estuary Trail: take 163 north to I-8 and exit heading west. Continue west along I-8 then north on W. Mission Bay Drive for a short distance before turning east onto Sea World Drive then south at South Shores parkway. Parking is along old Sea World Drive with more places to park west toward Friars Rd. To reach the San Diego River Pathway: take 163 north to I-8 and exit heading west. Continue west along I-8 then exit north on Hotel Circle north, following it west as it becomes Hotel Circle Place. Parking is along the street near the baseball field.
Hiking length: North trail, 3 miles out and back for a total of 6 miles. South trail, 4 miles out and back for a total of 8 miles.
Difficulty: Easy, the trail is paved and flat with very little elevation gain. Hiking, jogging, biking, and dogs on leashes are allowed along both trails; however, along the west end of the north trail, dogs are restricted to only certain times.