Flooding in the Willits Little Lake Valley

January 9, 2023

Being out in the valley after so much rain is always a marvelous experience. The ‘Little Lake’ can cover the central and northern part of the Willits Valley and provides extensive aquatic habitat and a winter home for waterfowl and raptors, similar to the large wildlife refuges of the Central Valley. We are part of the Pacific Flyway which is a 4000-mile-long and 1000-mile-wide migratory route for more than 300 species of birds. This migration happens twice a year, in the Fall/Winter and in the Spring/Summer. The sounds of Canada Geese, and several species of ducks including American Wigeon, Mallards, and Green-winged Teal fill the air. The many species of waterfowl that stop over when our creeks overflow and inundate large swathes of wetlands are eating smartweed, timothy grass, water plantain seeds, and other plants and invertebrates that live in the soil. Ducks and geese are constantly moving along the shallow edges of the wetlands or diving under the water.

Most of the animals that live on the mitigation project are adapted to the seasonal flooding and as I watch the elk herd, deer, coyotes, and other mammals, I see them adjusting to the water levels and finding higher ground to keep dry. Some predators, like foxes and coyotes, now have better access to a favorite food because gophers, voles, ground squirrels and rabbits are getting to higher ground and become more concentrated with less area to hide. Also, some of the small mammals succumb to drowning or become less mobile which makes them more vulnerable to predation. Small mammals not only contend with the coyotes and foxes, but also face predation from birds including Great Egrets, Great Blue Herons, Bald Eagles, and hawk species such as Red-tailed and Red-shouldered Hawks.

In addition to being an important food source, gophers and voles contribute to the landscape by aerating the soil with their tunneling. This system of underground tunnels allows water to move through and into the ground, helping to prevent erosion and slow surface runoff.

The trees that you see standing in the water right now are species that are adapted for inundation. The Oregon ash and the Valley oak are two examples of tree species that can tolerate winter flooding. Both trees are deciduous which may help them survive being underwater during the winter since their growth and energy requirements are reduced dramatically. The large Valley oaks on the northern end of the valley resemble island oases in the lake.

Winter flooding in the Willits Valley also has an important ecological benefit to us humans because it helps recharge the water table. Wetlands and floodplains cause water to slow and sink down into the soil, plus act as a filter for pollutants and trash that are moving downstream heading for the ocean. Willits residents are witness to this seasonal phenomenon. Some years are more spectacular than others, but we always have some flooding from the surrounding watersheds that feed the many creeks that cross the valley floor. It is important to remember that there are benefits to not only us but also to the creatures and plants that live here too.