Suisun Marsh

In 1993 I was asked to take over a California wetland mitigation project. The woman who had barely started it had transferred out from one of our east coast offices, but had clashed with the engineer who ran our Concord office. After only a few months and with one completed project in the northeast corner of the state, she had left for an opportunity in Atlanta. As the only other ecologist in the company with previous California experience, I was asked to take over the permitting and mitigation design, and as a result I worked about half time from Concord over the next year or two on this and another project.

The project involved the widening of SR 12 through Suisun City, in Solano County. The decision had already been made to mitigate the filling of a roadside ditch through wetland re-establishment on the adjacent Hill Sough Wildlife Area, and an agreement to that effect had been negotiated with California Department of Fish and Game. The outlines of the concept were in place; the deep, straight ditch would be replaced by a meandering brackish and tidal slough. There would be about nine acres of adjacent seasonal wetlands, and the mitigation site would be separated from the Wildlife Area by a dike. We weren't happy about this last part, but CDFG insisted upon it.

My role was to help work out the final design details and then to obtain the permits. We brought out a hydrologist and designed a weir to keep a small area of fresh water below the outfall (the upper segment of the stream was underground in a  residential neighborhood) as pond turtle habitat. I modified the elevations and some of the channel contours to minimize "islands" of upland that might serve as weed traps. I worked with a local landscape architect to develop a planting plan, after first educating him on why non-native ornamentals were not an option (he learned quickly and ultimately did well).

Then I got the permits. These were almost too easy. The Corps of Engineers was quite cooperative. There were no issues with the dreaded Bay Conservation and Development Commission, it was the first time I'd dealt with them and I didn't know any better. Possibly stopping by their San Francisco office to meet staff and ask to use some of their publications for research helped.

The project was built in the fall of 1994, and I visited every couple of years for a while. At first it was fairly successful. We met the permit requirements at the end of year five (Caltrans did the monitoring, I visited on my own time).

Then they walked away. After 1999, no one did anything to manage the site. After another 10 years, the trail had cracks in the pavement and the interpretive signs were too faded to read.

The interior of the site still looked pretty good, still met performance criteria. This included the new channel and the nine acre seasonal wetland, so actually most of the site looked pretty good. The problem was the upland buffer between the channel and the road. It was pretty weedy. Only an acre or two, but still.

I learned the importance of long-term management. I also learned not to place mitigation sites contiguous with roads, if at all possible. It hadn't been a choice in this case, we'd pressed as far into the Wildlife Area as we realistically could.

Overall, the mitigation site is a big improvement over pre-project conditions. I'd always like to see better, however I've got to acknowledge that we met the stated goals even without long-term management. We'd provided additional habitat for two listed species known on the adjacent lands, Suisun shrew and salt marsh harvest mouse. We'd eliminated habitat for non-native gobies documented in the ditch before the project. We'd removed a considerable amount of compacted fill which had encroached into the margin of Suisun Marsh, the largest estuary in the western U.S. And I'd gained California project and permitting experience. More on that in the next post.

Although I disliked working in the suburban car culture that is Concord… it was faster to get in the car to go to lunch than to walk across the six lane street, which was dangerous… I did very much enjoy the project area. Often I'd drive down to the end of Hill Slough Road, past the golden treeless hills and the endless marshes. In the evenings I'd eat in Fairfield or drive over to Berkeley and browse bookstores after dinner. One weekend I drove up to Tioga Pass, making snowballs at 11,000 feet after crossing the baking 100-degree central valley. I took full advantage of the opportunity to expand on my earlier experiences in Southern California, San Francisco, and Mendocino County.