A River in Time: The Napa River Ecological Reserve

A glimpse into the history of the Napa River.

Did the Napa River always look like a small green ribbon winding down the valley?

All rivers change the way they meander and flow across the landscape over time. Weather, geography, and human use can alter the course of a waterway, and the Napa River is no exception. The river we see flowing through our valley today is very different from the river that flowed through 300 years ago. It is narrower now and much of the marsh, oak and riparian (waterside) woodlands that cloaked the banks of the river have vanished. Agricultural and urban development have restricted the Napa River, making it hard to imagine what it must have been like before European settlement. However, you can still catch a glimpse of the river in its most natural state at the Napa River Ecological Reserve just outside of Yountville.

The Napa River Ecological Reserve, known by locals as the EcoReserve, is a multi-agency effort to preserve the last natural state Valley oak and riparian woodlands on the Napa River. These 73 acres of protected land along the banks of the Napa River gives us a view of the landscape that once defined the Napa Valley and provides habitat to nearly 150 species of birds, butterflies, and mammals. This oasis in the valley supports a diverse community of 238 different plant species, including California bay, white alder, Fremont’s cottonwood, Oregon ash, multiple species of oak and willows, snowberry, Himalaya berry, Santa Barbara sedge, and the endangered Sebastapol meadowfoam. The woodland canopy (overhead tree coverage) shades the river, creating cool pools of water for Chinook salmon, Steelhead trout, amphibians, crayfish (crawdads), and freshwater shrimp. Valley oak and coast live oak hosts lichen and provide shelter and acorns to feed local wildlife. Wild native grape vines climb the tall trunks and the grassy understory provides cover and insects for the nearly 70 species of birds that nest in the reserve throughout the year.

The Ecological Reserve is internationally recognized for its birdwatching. A few of the avian species visitors may observe include Wilson’s warblers, Anna’s and Allen’s hummingbirds, Stellar & western scrub jays, woodpeckers, white-breasted nuthatches, and yellow breasted chats. An interpretive trail identifies some of the more common species in the park and posted guides idenitfy the many species of plants, animals, birds and insects that visitors might spy as they hike the trails and enjoy the cool waters of the Napa River. Because the California Fish and Game Commission has given the Napa River Ecological Reserve “ecological preserve status”, these plant and animal communities will be protected for generations to enjoy.

Over the past 200 years, over ninety percent of the California riparian habitat has disappeared. Settlement and land development has drastically changed how waterways interact with the land. The Napa River Watershed has undergone different phases of land use that have altered the course of the waterways and shaped them into what we see today. Before the presence of white settlers, the Napa River watershed was managed for thousands of years by indigenous people, like the Wappo, who had minimal impact on the course and flow of the river. Controlled burns on the valley floor helped clear grasses and promoted the health and fertility of oaks and other species.

During the nineteeth century, as the Spanish and others attempted to colonize California, agriculture and grazing were imposed on the watershed. In 1836 George C. Yount received the land grant for Rancho Caymus. The land currently occupied by the Napa River Ecological Reserve was used as a campground for large annual religious gatherings. Earthen dams were built to support farming, ranching and vineyards and logging started for local use. This brought about the first significant changes in the watershed, including changes to the banks and flow of the river and its tributaries.

In 1848, the United States officially took over the land and American interests accelerated land use and development. Logging quickly diminished redwood groves and wetland marshes were drained for agricultural use. Water was diverted from streams for household use, and ditches and channels begin to define the flow of the river. Valley oak woodlands were cleared for prune, pear, and walnut orchards, vineyards, and dairies. Commercial use of the river lead to major dredging by the Army Corps of Engineers. Bridges and large dams such as the Milliken dam further alter the drainage of the watershed.

World War II and the expansion of Mare Island ushered a second wave of intensive development within the watershed. The population booms of Napa and Calistoga created the need for large-scale reservoirs and increased agricultural demands created a shift from dry farming to irrigation. Subdrains were widely used to improve drainage to expand farming land use and urbanization increased the amount of impervious (not allowing water to pass through) surfaces and storm drains. Farms and vineyards encroached upon riparian habitats, resulting in the narrow waterways that make up most of the Napa River watershed we see today.

As the health of the watershed rapidly declined, environmental awareness and conservation efforts began to increase. Restoration efforts to return the river to its more natural state while accommodating agricultural land use are beginning to define the next phase of land use in the Napa River watershed. The Napa County Resource Conservation District works with private landowners to remove fish barriers, restore riparian habitats, and prevent erosion and storm run-off. This helps decrease the amount of fine sediment in the river that is harmful to aquatic life. The Rutherford Dust Society has emerged as a leader in private landowner efforts, bringing together several wineries and growers to rededicate private land to successfully restore several miles of the Napa River. The Rutherford Reach Restoration project has improved the ecological diversity of the river while improving flood control to decrease damage to adjoining properties. 

Although the river can never be returned to its pre-colonization natural state, restoration efforts can help us strike a balance that allows people live in greater harmony with the watershed. As we develop a greater understanding of watershed health and engineer solutions to environmental challenges, we can return more stretches of the river to a state similar to what we see when we visit the Napa River Ecological Reserve. EcoReserve is a reminder of the dynamic ecosystems in our watershed and a vision for the future health of the river.

Check us out! Books and resources available from the Napa County Library:
1). Tal-a-ha-lu-si (beautiful land):History of Napa for Children by Ruth E. Mara
2). Habitat Protection by Natalie Smith
3). Trees to Know in Napa Valley by John E. Hoffman
4). Birds of Napa County by Hermann Heinzel
5). The California Field Atlas by Obi Kaufmann
6). Napa Valley Historical Ecological Atlas by Robin Grossinger


Go deeper! Explore these great resources online:
Napa River Ecological Reserve website
Chart of Bird Sightings by Season
Napa River Ecological Reserve Flora & Fauna Guides
Napa River Ecological Reserve curriculum guide
Napa Watersheds Wildlife Guide

Click on the images below to learn more:

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