Paul McHugh of Bay Nature Magazine wrote a very nice long-form piece on Cullinan Ranch in the San Pablo Bay from a kayaker’s point of view, including some of Ducks Unlimited’s work on the project.
So at Cullinan Ranch, Ducks Unlimited—one of ten outfits cooperating with USFWS on the restoration—was asked to help with the design. Russ Lowgren, an engineer with DU, has eight years’ experience crafting habitat restoration in California. A big part of his job at Cullinan was protecting Highway 37, which forms the unit’s southern boundary, from the impact of erosive forces. This was achieved by burying blocks of “geofoam” (expanded polystyrene) at the proper angle to dissipate wind and wave energy along the edge of the roadway. These blocks were sealed in a special membrane to reduce potential decay from fuel spills or oil leaks.
Another key concern was exactly how much tide influx to permit. The right amount would allow the waters to drop sediment and build up natural mud banks and sloughs; too much would scour these structures and stymie the growth of native vegetation. “I decided the solution was to connect this bathtub with a straw,” Lowgren told me.
This decision means the thousand acres of water constituting the main Cullinan pond are filled and drained through just three levee breaches. For the paddler, this means two things. Currents inside the pond are negligible, so if the tide is high enough to float your boat, you’re pretty much good to go. However, currents at the breaches can grow potent, on the order of a Class II whitewater rapid. So if you plan to navigate through them, “going with the flow” is a rather important principle.
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