DWR Begins Monitoring Vernal Pools

Some grasslands, including areas around Butte County, have an underlying impervious layer of rock or clay that causes rainwater to pond in the winter and spring, creating seasonal wetlands called vernal pools. Although vernal pools are only a small component of our local grasslands in terms of area, they support a remarkably high diversity of plants and animals, including rare and endangered species and species endemic to California (i.e., found nowhere else in the world).

Vernal pool organisms and plants are highly specialized to their unique environment and to the Mediterranean-type climate found in California. They have adapted to living in pools that fill in the winter but are completely dry by the summer, as well as adapting to the sometimes-extreme variability in temperature and rainfall between years. Vernal pools are important targets for conservation because most vernal pools in California have been lost to development, agriculture, and habitat degradation from invasive plants.

 Vernal pools often support spectacular wildflowers that bloom from March to May. Each spring, Department of Water Resources (DWR) environmental scientists from the Oroville Field Division monitor hundreds of vernal pools around the Oroville area and make assessments on how protection measures for these valuable environmental resources are succeeding.

This year scientists are observing wildflowers blooming earlier, likely due to drought conditions, which has reduced the number of “wet” vernal pools found. Scientists also noticed that the areas where CAL FIRE performed controlled burns around the Thermalito Forebay last year to remove invasive grass buildup, or ‘thatch’, and other invasive plants, are abundant with flowers – demonstrating the benefit of such activity on area grasslands and vernal pools.

Oroville Recreation

The Loafer Point, Bidwell Canyon, and Lime Saddle boat ramps are open. The Oroville Dam Spillway boat ramp remains closed for repairs. The Foreman Creek and Stringtown cartop boat ramps are also open.

Intermittent, short duration closures of the Oroville Dam Crest parking lot may occur to accommodate Lakeside Access Road construction activities. The popular walking/bicycling trail across the top of the dam will remain open and parking will continue to be available at the Upper Overlook.

Information on current boat ramp status can be found on the California State Parks’ Lake Oroville State Recreation Area webpage. Scroll down to the link for “Current Launch Ramp Status”.

The Lake Oroville Visitor Center is open to the public on Tuesdays, Wednesdays, and Thursdays from 9 a.m. to 5 p.m. Pick up the Lake Oroville Trails Map, which shows more than 91 miles of trails available to equestrians, bicyclists, and hikers, at Lake Oroville State Recreation Area (LOSRA) kiosks, the Oroville Area Chamber of Commerce, and Feather River Recreation and Parks District. The Loafer Creek Recreation Area continues to be closed due to waterline repair (boat ramp and trail access allowed).

Visit the California Parks LOSRA webpage for current information on facility status and campground reservations. An interactive map of recreation facilities in DWR’s Oroville-Thermalito Complex is available on DWR’s Lake Oroville Recreation webpage. Information about the 11,000-acre Oroville Wildlife Area is available on the California Department of Fish and Wildlife webpage.