Adopt-a-trestle in the Yolo Bypass

Davis Senior High School at Yolo Bypass Wildlife Area
SLEWS Program | Sacramento Valley | December 10, 2019

Participating School
Davis Senior High School

Yolo County Resource Conservation District
Yolo Basin Foundation

Allie Igwe, UCD Graduate Student
Brian Keegan, Sacramento State Graduate Student
Randy Wittorp
Xerónimo Castañeda, Conservation Project Associate, Audubon CA

Summary of the Day
“What’s it near?”

When people ask this question about the Yolo Bypass Wildlife Area SLEWS project, I just don’t know what to tell them! Located about 30 minutes south of the highway 80 Yolo causeway on gravel and dirt roads, this site is about as remote as it gets for SLEWS projects. First on the list of “to do’s” for this project was figuring out a way to get 35+ students, teachers, mentors, and project partners to the correct site. For all you bypass hunters out there, we needed to meet at parking lot M – the furthest from 80 – so we met mentors and parent drivers at the Yolo Basin Foundation Headquarters to start the caravan. There was lots of birds to see on the bumpy ride – I spotted Sandhill Cranes, Northern Harriers, White-tailed Kites, coots and lots of waterfowl like Northern Shovelers and Northern Pintails. We were lucky this time that the road was only somewhat wet and muddy – we may not be so lucky after a few winter storms!

The Yolo Bypass is a manmade system of weirs that diverts floodwater away from the Sacramento River and thus prevents the city of Sacramento from flooding during the rainy season. As you can imagine, this means that some years the bypass is under water.

What happens to bypass wildlife in these years? Well, the water usually comes in from the east and moves west, so they may be able to move west before their home is underwater. And if they don’t? Well, there used to be a railroad spanning the bypass, and the “trestles” that once elevated the tracks are still present. During flood events, these become the only islands of dry land – drones have captured photographs of animals like coyotes, deer, and rabbits stuck on these small land masses. The problem is these trestles aren’t high quality habitat – and that’s where we come in!

Yolo County Resource Conservation District has planned a project to vegetate these trestles, creating wildlife corridors in the bypass. They’ve chosen plants that not only provide food and cover for sheltering wildlife but of course are flood-tolerant as well.

After arriving and enjoying breakfast, students heard all this and more from Martha Ozonoff, the Executive Director of the Yolo Basin Foundation and Alex Tremblay, Project Manager from Yolo County Resource Conservation District. Then it was time to divide into mentor groups and get started!

This project is unique in that each mentor group is tackling a single railway trestle over the course of three field days. On this day, the project task was to install a drip irrigation system to support the plants we’ll plant on the second and third field days. Each mentor group was shown an example – three parallel lines of irrigation along the entire mound, connected to a perpendicular line – before setting off to complete their own system. Groups had to problem solve to make the system work for their particular trestle. One group had to navigate around a large mound in the middle of their trestle, while others had to avoid rocky trestle sides. Once the line had been spooled out, students installed 100 emitters on the lines. Next time we’ll be planting native shrubs alongside these emitters, which will ensure they have water when the bypass is dry. One group was so dedicated to caring for their trestle that they picked up trash to clean it up before their next visit!

After lunch, students interviewed the mentors to learn about their education and career paths, as well as getting to know them better for the field days to follow. To close out the day, we shared our favorite moments of the day. This group was really interested in wildlife and mentioned finding deer antlers and even a dead opossum and coot!

Looking forward to our next Field Day on January 7th!