The trail cuts through the cattails and tules

In 1969, the Buena Vista Lagoon was set aside as California’s first ecological reserve. It continues to be a refuge for birds and other wildlife and can be a great place to observe migrating waterfowl, as it is a significant stop on the Pacific Flyway. Of all the lagoons along San Diego’s coast, it is the only freshwater lagoon, although this may change in the near future.

Walkers of all abilities will have no difficulty with the paved sidewalk along State Street and Carlsbad Boulevard that crosses the lagoon, but some may run into difficulties on the muddy trails within the lagoon. Leashed dogs and bicycles also are allowed on the paved Coastal Rail Trail that runs along both sides of Carlsbad Boulevard, but dogs and bicyclists are not allowed within the Nature Center or on the lagoon trails.

The hike to the Nature Center and the trails leading into the lagoon are open year around but could be closed due to flooding after heavy rains. Birding is best from the observation platforms within the lagoon that can be accessed via trails originating at the Buena Vista Audubon Nature Center. The Nature Center is open Tuesday through Saturday, 10 am to 4 pm, and Sunday, 1 pm to 4 pm, but the lagoon trails are open for birders and walkers daily from sunrise to sunset.

Before beginning the walk, take time to view the lagoon from the perspective of the small hill within the Maxon Brown Park. In addition to the beauty of the view, a closer observation will reveal that open water is rather limited. The shoreline is dominated by dense thickets of tule (several species of Schoenoplectus) and southern cattail (Typha domingensis).

Start walking on the sidewalk along Laguna Drive to its intersection with State Street. Continue right on State Street, then around the traffic circle, remaining on the sidewalk on the east side of Carlsbad Boulevard. As you look east, what you will see is a wall of cattails and tules, brown in winter but green the rest of the year, rising from a point a few feet from the sidewalk to a height of nearly eight feet. A variety of native and non-native species compete for light and water in the space between the cattail and tule curtain and the paved path. One of the most common of the native plants in this limited space is San Diego goldenbush (Isocoma menziesii). It puts on an attractive show of bright yellow flowers in late summer and fall. In a wet winter, Bermuda buttercup (Oxalis pes-caprae), a persistent non-native pest with attractive yellow flowers, may make an appearance amongst the abundant iceplant (Carpobrotus edulis). Another native California plant found here, but clearly out of its comfort zone, is the Monterey cypress (Cupressus macrocarpa). These trees, planted here some years ago, are surviving but are not happy.

You will reach the Audubon Nature Center after walking 0.4 mile from Maxon Brown Park. Turn right and follow the signed nature trail east, past picnic tables and benches, a kiosk with information about the lagoon, and labeled coastal sage scrub plants. Continue following this path beyond the parking lot on your left and out into the lagoon. A path has been cleared of cattails and tules, making for easy walking, though in spots it can be muddy. Continuing down the path will bring you to a patch of open water and the first of two viewing platforms. From here you will see another similar viewing platform on the other side of the open water. The water here is quite shallow with a mud bottom, an ideal environment for dabbling ducks such as Gadwalls, American Widgeons, Northern Shovelers, Mallards, and Ruddy Ducks. All of these are common winter visitors to the Buena Vista Lagoon that you might see from these viewing platforms. Other occasional visitors to these waters include Eared and Western Grebes, American White Pelicans, Great Blue Herons, Cormorants, and Great and Snowy Egrets.

Unfortunately, the shallow waters and muddy bottom that make the Buena Vista Lagoon a great place for dabbling ducks also signify that its life as a lagoon will soon be over unless steps are taken to reverse its rapid eutrophication. This is caused by the continued accumulation of sand and silt brought into in the lagoon by Buena Vista Creek, the small stream that is its main source of water, as well as the accumulation of dead and decaying vegetation.

In 2001, the California Department of Fish and Game (as it was then called) began restoration of this lagoon with an emphasis on removing the cattail-tule vegetation choking the shore, but the project soon ran into a number of problems. Ten years later, the agency turned lagoon restoration over to SANDAG (San Diego Association of Governments). After numerous studies, they came up with four restoration plans. The major reason the lagoon is silting up is that a private dam (called a weir) was erected near where the lagoon flows into the sea. Its purpose was to keep the water level in the lagoon slightly above the average high tide. This converted the lagoon into a “fresh water” lake, but it also stopped the flow of sand from Buena Vista Creek into the ocean and onto San Diego’s beaches. The sand and silt just accumulates in the lagoon.

All the proposals call for cattail-tule removal, but from biological and economic perspectives, only two of the four proposals go on to outline a doable course of action that makes sense. Either get rid of the weir and open the lagoon up to the tidal flushing or do nothing and let it become a meadow. SANDAG held a meeting in November 2018 to decide which of these plans to put into action. However, no decision was made. Instead, they decided to delay a decision for another six months. So, after nearly 20 years of talks, the decision was to talk some more.

BUENA VISTA LAGOON & AUDUBON NATURE CENTER (Carlsbad)

This freshwater lagoon is a great place to observe a variety of birds.

Buena Vista Lagoon map

• Driving directions: From I-5 north, take the Las Flores exit in Carlsbad. Turn left on Las Flores, cross back over I-5, then go left on Jefferson Street. From I-5 south, take the Las Flores exit in Carlsbad and turn right, then go left on Jefferson Street. Continue south for 0.4 mile to Laguna Drive. Turn right on Laguna and continue 0.3 mile to Maxon Brown Park, on your right. Park on the street and begin your walk. Hiking length: 1.2 miles, out-and-back. Allow 1.5 hours. Difficulty: Easy with negligible elevation gain/loss.