Tijuana Estuary

Visitor Center at estuary

The Tijuana River National Estuarine Research Reserve (or Tijuana Estuary, for short)

is a multi-agency key location for research, collaboration, education, and (hopefully) environmental improvements to this delicate ecosystem. Designated by NOAA (National Oceanic and Atmospheric Administration) as one of 28 estuarine reserves, it is also part of a bi-national site. Three quarters of the watershed for this estuary is within Tijuana, Mexico.

Estuary in fore-ground, with US/MX border fence mid photo 

Within the US boundaries of this project exist the Tijuana Slough National Wildlife Refuge,  Border Field State Park, Navy lands, and San Diego County and City properties. Estuary management is shared by the US Fish and Wildlife Service and the California Department of Parks and Recreation.  Hopefully, this is not too confusing, but I want to acknowledge the collaborative efforts ongoing within this estuary area.

Gary and I dropped by the estuary Visitor's Center for our first visit, collected some information, and then returned for a posted Saturday nature walk led by two volunteers. Education for all ages is a focus, with many research programs ongoing “in the background”.  While I would’ve gladly spent time to learn more, the nature walk did give attendees a great overview of what was there.

Just outside of the visitors’ center, the docent/volunteers provided background for our walk, using a site diagram/map painted on the patio (art is everywhere in CA!).  And, this was a great way to get oriented before heading out on the trail into the various habitats within the Reserve.

Starting with Gary and me, the guides ended up with about 10 taking the tour

An overarching message was the importance of an estuary (and, of course, the need to protect this area).  Estuaries provide food sources and habitat – to migrating and local birds and to many other wildlife. 

It was close to mid-day and the birds and other animals were not out in "masses" but Gary did capture a few photos.

Bunny along the trail

Crabs at low tide in the stream going to coast

Estuaries are also important for flood control, and pollution control.  And trails throughout the estuary provide a source for recreation and education - whether you take a guided walk, or one on your own.

A brochure lists the following habitats within the estuary - dune, salt panne, salt marsh, mudflat, brackish pond, riparian, coastal sage scrub, and vernal pool. You can move from one habitat to another by very small (less than a foot) changes in elevation, by the presence of saltwater, and/or by the type of soil. 

Looking across several types of habitat - with a plants study in foreground

As I expected, the plants growing in an area are often a signal that you are in a particulart habitat.  In the wetlands area (with brackish water – a mix of salt and fresh water sources) we observed three levels of plant life representing the low, mid, and high tide levels in the wetlands.

Cord Grass nearest the water, with pickle weed in the foreground

In the low section - nearest the water, cord grass was growing.  Just a little higher in the mid-level was a plant called Pickleweed, and in the higher elevation was salt grass.

Pickle weed closeup - plants resemble pickles..

And, just a little higher from the water was salt grass.

These wetland plants, using the brackish water, were considered halophytes – plants that manage salt from the brackish water as a cycle within the plant and then have the ability to excrete the salt. 

Looking out over the estuary towards the dunes and ocean, we noticed a long row of wooden structures. The docent explained these were remnants of an old system (long before the area became protected) that disposed of untreated sewer waste - a habit from the past. [ Before environmental harms were well defined - "Dilution is the solution to pollution" was a common practice]  The metal tubing transporting the waste is no longer there.   However, a decision was made to leave the wooden sections since trying to remove them would be more harmful to the estuary than leaving it.

 
Some examples of plants found along our walk in other habitats are shown below.

A few types of cacti, like this prickly pear were found 

Several tree species, like sycamore and willows, were found is the riparian area. Some, remnants of times with more fresh water sources, are not thriving as well today.

Tree in the riparian area with blooms used as "Christmas Trees" for model railroads

The Coastal Sage Shrub habitat included many herbaceous and woody plants, and succulents.  Here are a few examples of these plants.

California Buckwheat - closeup below

These beautiful penstemons were also in bloom. Unfortunately, I am unsure of the exact species.

There were several types of sage species native to the coastal sage scrub habitat.  I remember seeing the Salvia Clevelandii, but we did not get any photos of them.

This beautiful succulent was blooming and quite attractive

However, the next succulent, with beautiful blooms is a fast-spreading non-native and is quite invasive.  The tour leader stated that the volunteers just cannot get it removed (reminds me of Bermuda Grass and some other invasive plants - always use native if you can!!)

We really enjoyed our time at the estuary and hope to return for a longer visit - maybe in the springtime when more birds are visiting there.

Much more information on this important estuary can be found here