A Local Treasure
Blooming native flowers burst in concentric rings as water recedes in the vernal pools that define spring in the Sacramento Valley. The presence of vernal pools adds to the quality of life we enjoy in Sacramento County.
The Department of Environmental Review and Assessment (DERA) analyzes impacts that projects within Sacramento County may have on vernal pools. Preservation of vernal pools is part of what DERA accomplishes by ensuring that projects within Sacramento County are in compliance with the California Environmental Quality Act (CEQA).
What are Vernal Pools?
Vernal pools are seasonally inundated depressions with an impermeable soil layer, which allows water to be retained for extended periods of time. The impermeable layer is formed from clay soils derived from the weathering ancient volcanic mudflows of the Sacramento Valley. The dense clay soils retain rainwater in shallow depressions during the winter and early spring. Water may fill and evaporate from vernal pools several times throughout the season. As spring progresses, water evaporates from vernal pools and is consumed by emerging plants. Specialized plants and animals are adapted to survive these drastic cycles of wetting and drying.
Habitat for Special Plants and Animals
Unique communities of specialized plants and animals, including some special status species, inhabit vernal pools. After months of dry weather, invertebrates, crustaceans, and amphibians emerge as rainwater fills the pools the winter. Plants sprout underwater with specialized adaptations such as floating leaves and hollow stems that act like straws to bring air to the roots. Spring flowers burst with color, attracting native bees. The water, plants and animals attract birds that come to feed and rest in the pools.
As the season changes from spring to summer, insects and crustaceans will produce reproductive cysts and eggs as water evaporates from the vernal pools. Amphibians will bury themselves deep in the protective mud and lie dormant along with seeds, cysts and eggs till the next rainy season. By the end of summer, pools are completely dry, and the plants and animals are protected deep within the soils until the next rain begins a new cycle.
Links to More on Vernal Pools:
Butte Environmental Council
California Vernal Pools Website
