Oct 20, 2014

Early observers who viewed the coastal lagoons of North County described glittering salt flats and shifting landscapes, according to a new report by the California Coastal Conservancy.

Mining regional and national archives, the conservancy, with the San Francisco Estuary Institute, reconstructed North County lagoons as they appeared to Spanish friars, 19th-century land surveyors, early scientists and others.

Using a technique called historical ecology, they painted a portrait of richly diverse estuaries that made themselves anew as competing forces of saltwater and freshwater claimed their space.

Today, the authors found, the lagoons are more static, with inlets fixed in position, habitat types more homogeneous, and hydrology driven by year-round urban runoff. They note, however, that North County retained far more of its original wetland acreage than other areas of Southern California.

While lagoons face different circumstances today than they did in earlier centuries, the ecological mosaic shown in historical records offers ideas of how to improve their condition.

“The study gave us a view of what the mix of habitat was in all of these systems collectively,” said Sam Schuchat, executive officer of the California State Coastal Conservancy. “It gives us a palette — if you think of a painter’s palette of different colors to choose from.”

For the lagoon study, researchers looked at a wide range of sources — from the Carlsbad City Library, lagoon foundations and the San Diego History Center in Balboa Park to the California Historical Society in San Francisco and the Smithsonian Institution in Washington, D.C.

They pored over journals of Spanish friars, railroad records and even personal letters and postcards.

“It’s ecological detective work,” said co-author Erin Beller, an environmental scientist with the San Francisco Estuary Institute. “We’re looking for any information we can find on the historical landscape. It could be someone whose horse fell into a creek and how deep the creek was, or a scientist collecting data, or a person writing back to relatives on the East Coast about their new home.”

Using geographic information software, they layered those observations onto 19th-century surveyors’ maps called topographic sheets that provide accurate images of land features.

Prominent in early lagoons were salt flats, often described in picturesque language.

“One of the first written accounts of Agua Hedionda Lagoon, a journal entry by Friar Juan Crespí from July 1769, describes the flat as a ‘salt deposit’ marked by ‘white glitter,’ ” the report stated.

In winter, those plains flooded to form wetlands teeming with waterfowl.

Many of the salt flats have been lost, the report said. The researchers also found that North County lagoons have lost much of their cyclical nature, with permanent openings instead of migrating inlets that varied the mix of salt and freshwater.

Those changes have occurred as highways and railroads crisscrossed the lagoon, cities grew up around them, and dredging, dikes and jetties reshaped their water flow. Meanwhile, the lagoons lost some of the wetlands, dunes and eelgrass beds that naturally absorbed ocean waves.

“We’re working very hard to keep nature in place,” said co-author Megan Cooper, a project analyst with the California Coastal Conservancy. “And it costs a lot of money to do that, because we’re not looking at what would naturally be able to sustain itself in that context.”

Doug Gibson, executive director and principal scientist of the San Elijo Lagoon Conservancy, called the report a “neat exercise,” but noted that it represents a snapshot of a particular period that could not easily be replicated.

“We have more than half a million people living in our watershed alone,” he said. “It all drains into our lagoon. We have 4 miles of roads and railroads that crisscross the lagoon, not counting roads that crisscross the creek. You couldn’t have the same system that you did. It isn’t practical or feasible.”

Nevertheless, North County’s relative isolation and early position as a backwater of Southern California allowed the area’s lagoons to maintain about 85 percent of their original footprint. Other parts of Southern California retained about 50 percent of their historic wetlands, turning the rest into housing tracts and marinas.

The baseline acreage is an important asset to the region, Schuchat said.

“You can (improve) a system that is pretty degraded but is still functional in some way, whereas it’s much, much harder to take a parking lot and turn it into a functional lagoon,” he said.

For Beller, the remaining lagoons are good canvasses for future restoration. The report, she said, can help guide that design.

“I think it’s easy to see historical research as an exercise in nostalgia, or something that is irrelevant,” she said. “But I think it’s been really exciting for me to think about what information this unlocks about our current landscape and future potential for management and restoration.”

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