5:22pm

Mon March 12, 2012
Health, Science, Environment

Historically smart land design

California's outer coast once boasted 27 miles of Bay Area beaches. Up until the 20th Century, these beaches provided a natural buffer for the inner land areas; then came freeways, airports and downtowns. KALW's Ben Trefny spoke with Robin M. Grossinger, Senior Scientist and Historical Ecology Program Director at the San Francisco Estuary Institute about California beaches, landscape heritage and how some of these areas have rebuilt themselves.

Grossinger's new book, Napa Valley Historical Ecology Atlas, Exploring a Hidden Landscape of Transformation and Resilience is out this month. In it, he looks at now-familiar places and explores what they were like in centuries past. Grossinger notes that we can use this historical perspective and current natural land trends to design smarter areas.

ROBIN GROSSINGER: Well, there are surprises almost every place we've looked. I mean, that is one of the interesting things. You realize we are all making it up as we go along. And people often wonder what it used to look like. So there is the risk that in these restoration efforts that we might mythologize or import ideas from the East Coast or Midwest of what a river should look like.

BEN TREFNY: It would make a great river there, right through the middle of Marin County and there never was one in the first place.

ROBIN GROSSINGER: Yeah. And maybe that is okay if it will work but it probably won't work out that well because many things are still the same. It's still a Mediterranean/semi-arid climate. The topography is still the same. The soils are still largely the same. So, there's plenty of ways to get it wrong. So yeah, pretty much every place we go, it's a slight surprise what we find. Scientists in the Bay Area didn't realize how many beaches there were. You think about beaches on the outer coast of California, but we had almost 30 miles of beaches in the Bay. And those were popular for all the reasons beaches are popular, up until the 20th century. Then they were all filled and pretty much gone and forgotten.

TREFNY: Filled as landfill and properties.

GROSSINGER: Yeah, freeways built out, landfill for airports and downtowns and all the important things of progress. But the interesting thing, when you look closely, is we have found that a lot of the beaches have come back in the meantime. They kind of rebuilt themselves. The processes are still there – tides and water and sediment.

TREFNY: Depositing sediment.

GROSSINGER: So you have a number of new beaches. You know seven, eight, 10 miles of beach that's come back in similar patterns of size and orientation but different spots, because it is accommodating and adjusting to the built environment.

TREFNY: Where is that happening?

GROSSINGER: Throughout the Central Bay, parts of Berkeley, Albany, San Francisco, Marin. And an interesting thing is that scientists looking at that – looking at the historical characteristics, and looking at what these beaches today look like – have started designing new beaches that might be strategically brought back or recreated to provide habitat for some species and also sea level rise buffers, to provide a natural buffer against some of the challenges we will face. It would be nice to have beaches bordering our communities, providing a little bit of protection.

TREFNY: And that is something that the natural environment might have had in the first place and that ended up protecting the land inside. But, wetlands and beaches have dissipated over time.

GROSSINGER: Right. So we realize that we can actually draw upon some of these historical examples to design the landscapes of the future and get back some of the functions we would like to have.

TREFNY: You have a book that is coming out. Napa Valley Historical Ecology Atlas, Exploring a Hidden Landscape of Transformation and Resilience. What is something in the Napa Valley that is completely the same in the last 200 years, based on your research. And what is completely different?

GROSSINGER: Well, one remarkable example of persistence is an oak grove that we were lucky enough to get to visit on a private property in the Oak Knoll area. The Lamareaux family. It's a rare place in the valley. The valley was covered with great oak trees – great valley oaks. Everyone was blown away by the beauty by this park-like landscape and grand trees. There are really no other examples in the valley of a big grove, although there are individual trees remaining. So this place is quite a beautiful spot. You get this feeling of being in a cathedral of oaks, these incredibly big trees – a whole world of bird life up above. Bizarrely enough, we went to the archive years after taking a photograph of that spot and found a photograph of that same spot that had been taken in 1907, exactly 100 years ago, almost to the day we took our photograph. It looks almost the same. You can see the same leaning tree. You can see the same mix of trees. You can see the same features persisting through time. Those points are real reminders that we live in a landscape. These processes are pretty strong. They aren’t suddenly going to go away.

TREFNY: What about on the opposite side?

GROSSINGER: I think one of the striking things on the Napa River, as well as pretty much every other river we have studied here in California, is how even when it looks pretty natural – a sinuous river with trees along side of it, a curvy river – how different that is from how it used to be. In Napa, there are places that the river looks somewhat natural but it turns out it is incised and cut down 20-25 feet, and it used to flow through wetlands and willow groves in a particular spot. Maybe it used to have a broad zone of wetlands and channels and complexities that was maybe thousands of feet wide and now it is just a narrow little strip.

TREFNY: As you talk about that, I imagine rivers that I see whether they are large are small, but they are all pretty contained. The wetlands surrounding rivers doesn’t appear in too many places. They are almost always creeks or channels of rivers and they end up resembling some sort of canal.

GROSSINGER: That is exactly right. One of the things that are hard to see in our contemporary landscape is how homogenized these systems have been even when they look slightly natural. They’ve been so simplified and restricted in terms of how they express themselves. So a lot of the effort in our work and book is to show the complexity and the diversity of the landscape. How different habitats express themselves. That complexity is what provided the bio-diversity and the resilience to variations in climate, floods, and droughts. Floods and droughts. The ability to respond to different climatic events is a lot of what we have lost in landscape today.

TREFNY: Of course, those rare climactic events aside, they do happen obviously, the regular floods. It is a lot easier to build a community around a controlled river than to build it all on stilts in the wetlands.

GROSSINGER: That is right. We aren’t going to go all the way back. The interesting thing is that many flood control agencies are finding their communities want something in between. They don’t necessarily want an engineered concrete flood control channel. They want flood protection but they are often willing to give a bit of land and have something that is a bit more aesthetically appealing, safer, and more ecologically functional. Napa River is a great example where they’ve done a living river approach to flood protection. They’ve used the wetlands and widening the river corridor to gain a lot of flood capacity for the city of Napa. The idea of natural flood protection, which is being applied to the Santa Clara Valley, this has a lot of potential to bring back elements of these systems still while providing flood protection. A lot of the engineering that happened in the 20th Century is not going to last forever. There is a 50-year lifespan, a 75-year lifespan, so a lot of the work that was done to bring nature under control in the 20th Century has to be redone in the 21st Century. We are getting a second shot at many of these things. You can see the Bay Bridge being rebuilt, salt ponds are turning over. A lot of the landscape is flexible and dynamic and continues to change.

Related Program