Pacheco Reservoir Expansion Would Drown Protected Land for Questionable Benefits
As Save Mount Diablo has expanded our advocacy south into the whole 200-mile-long Diablo Range, we have joined several coalitions.
We’ve joined these coalitions to oppose badly sited water projects like the Pacheco Reservoir expansion in Santa Clara County that’s proposed by the Santa Clara Valley Water District (Valley Water).
An effort led by the Stop Pacheco Dam coalition includes
- landowners who would be negatively affected by the project;
- local residents concerned about impacts to wildlife habitat and rising water rates; and
- advocacy groups like Friends of the River, Center for Biological Diversity, CalWild, Sierra Club chapters, and others.
We have been working to oppose this harmful project for years and bring decades of experience in responding to land use threats.
Most recently, our photographers Scott Hein and Cooper Ogden had the opportunity to visit this rugged area east of Henry W. State Park.
They took amazing photos and drone video to help share with the public this special part of the Diablo Range that the new proposed dam and reservoir expansion would destroy.
This project’s skyrocketing costs, lack of public benefits, and negative impacts on important wildlife habitat mean Valley Water should immediately dismiss it as a serious proposal.
A view of the current Pacheco Reservoir. Though relatively small, reservoirs in the wrong place create huge environmental impacts, especially by blocking crucial corridors that wildlife use to search for food, find mates, and survive changing environmental conditions. The new dam placed upstream on the North Fork of Pacheco Creek would inundate rare landscapes such as sycamore alluvial woodland and disrupt important wildlife movement corridors. Photo: Scott Hein
The current Pacheco Reservoir is a small body of water that is currently in disrepair.
It sits in the middle of Pacheco Pass and covers about 200 acres of land, about 5,000 acre-feet of water, north of Highway 152 and southeast of Henry W. Coe State Park.
Valley Water wants to expand the reservoir by more than 20 times to a massive 140,000 acre-feet (more than enough to cover the City of San Jose in a foot of water), drowning 1,500 acres of beautiful open space.
What Is at Stake?
This new larger reservoir would block a designated critical wildlife linkage in the ecologically diverse Diablo Range.
According to the Critical Linkages: Bay Area & Beyond report, all kinds of wildlife, including tule elk, mountain lion, bobcat, deer, and California quail depend on the area that the proposed Pacheco Reservoir expansion would destroy.
For many wildlife species, a reservoir blocks movement as effectively as a wall does. This barrier could disrupt life-cycle behaviors and key movement routes for many species.
Eagle nesting sites would also be drowned, and more than a thousand acres of upland foraging habitat.
Plus, two breeding sites for the rare and threatened California tiger salamander and California red-legged frog would be negatively impacted if the land around the current reservoir were flooded.
A bald eagle watches over its nest in the area that Valley Water proposes to flood. Photo: Scott Hein
The project would flood 150 acres of protected land on The Nature Conservancy’s Romero Ranch conservation easement area, as well as a portion of Henry W. Coe State Park.
If such lands that are already considered “permanently protected” can be drowned and destroyed, then what does “protected” land even mean?
Lands impacted by the expansion of the Pacheco Reservoir (red). The Romero Ranch easement area to the northeast and Henry W. Coe State Park to the northwest are lands already protected that would be drowned by the project. Map: provided by the Stop Pacheco Dam coalition
Financial Insanity
Although the ecological harm this project would cause would be severe, its financial impacts are also terrible.
When Valley Water applied to the state seven years ago for funding, it said the new reservoir would cost $969 million. Since then, costs have tripled to $2.7 billion. With inflation and finance expenses, final costs may be above $5 billion.
Though Valley Water claimed it would secure partnerships with other water providers to help share the costs and the water, no partners have been found.
Valley Water has failed to complete the environmental review necessary to secure major permits to start construction, failed to secure water rights, and only completed 30 percent of the project design.
By middle of next year, projections show Valley Water will have spent $132 million to get to this point—nowhere.
Looking further south into the Diablo Range from above Lawler Ranch, much of which would be flooded by the proposed Pacheco Reservoir expansion. Photo: Cooper Ogden
Rate payers served by Valley Water would foot the bill to try to construct the new dam in this geologically unstable area.
Other less costly alternatives, such as partnering in the expanded capacity of San Luis Reservoir or groundwater storage, make more sense for Santa Clara County ratepayers and would leave this area intact for wildlife and future generations.
Views from the top of the Lawler Ranch, revealing the valley that would be flooded. Photo: Scott Hein
What Is Save Mount Diablo Doing?
Save Mount Diablo is working with allies in the Stop Pacheco Dam coalition to protect the beautiful open space and crucial habitat that the proposed new Pacheco dam and expanded reservoir would destroy.
The North Fork of Pacheco Creek in the upper part area of the Lawler Ranch, which would be flooded by the new dam and reservoir expansion. Riparian areas like this are crucial biodiversity hotspots and are the most important habitat types used as wildlife corridors for many species. Photo: Scott Hein
We’ve recorded beautiful images and video of the areas that would be drowned if the new Pacheco dam and proposed Pacheco Reservoir expansion proceeds.
Many thanks to the landowner and Stop Pacheco Dam coalition coordinators for facilitating our tour and helping us share the beauty and importance of this amazing place with the public.
Save Mount Diablo staff discussing maps on a site tour of the proposed project. Photo: Juan Pablo Galván Martínez
Save Mount Diablo drone pilot Cooper Ogden prepares to take aerial video of the beautiful land that would be negatively affected by the proposed new dam and Pacheco Reservoir expansion. Photo: Juan Pablo Galván Martínez
Save Mount Diablo also helped fund biological surveys of the impacted area to identify rare species, and it’s paid off! Exciting news has come to us that a biologist working with the coalition detected a probable occurrence of Crotch’s bumble bee (Bombus crotchii) on the ranch we visited. Why is this important?
Female Crotch’s bumble bee (Bombus crotchii), which is a candidate for listing under the California Endangered Species Act. This rare pollinator needs help, and habitat for this species would be lost if the proposed Pacheco dam is built. Photo: Jaymee Marty
Like many pollinators, the Crotch’s bumble bee is in steep decline; it has suffered an estimated 75 percent reduction in its range. Currently this species is a candidate for listing under the California Endangered Species Act.
As a candidate species, it is protected much like a species that is already listed as threatened or endangered. The proposed Pacheco dam project and subsequent reservoir expansion may result in harm or death of Crotch’s bumble bee, and would certainly result in the destruction of its habitat.
Coalition biologist surveys for rare species in the area that would be flooded. Photo: Juan Pablo Galván Martínez
Part of our strategy for defending the environment from the proposed Pacheco dam consists of speaking at public meetings where agencies such as the California Water Commission discuss the project.
We hope that decision makers realize the project’s excessive costs and destructive environmental impacts cannot be justified.
The California Water Commission is aware of these issues.
After hearing comments from Save Mount Diablo and others, California Water Commission members expressed concern over the delays and the funding being held hostage by Valley Water, instead of being spent on viable projects.
North Fork of Pacheco Creek. This area and its surroundings would be drowned by the proposed expansion of Pacheco Reservoir. Photo: Scott Hein
California is being made drier and hotter by human-caused climate change. And storms, floods, fire, and other extreme types of weather are more intense, more frequent, and affect a larger area.
Given these conditions, good water solutions include recycled water, more groundwater banking, water conservation, and massive action at all levels of society to confront the climate crisis.
We will continue to oppose the proposed Pacheco dam and reservoir expansion and other badly thought-out water projects.
And we’ll encourage sound land use policies in the Diablo Range to better protect open space and give plants, wildlife, and human communities a chance to thrive in this region, one of the most beautiful and biodiverse landscapes on the planet.
Your support of Save Mount Diablo allows us to continue this vital work. You can learn more about how to support us, and sign a petition asking that the US EPA not allocate any more loans to this harmful and costly project.
The Quien Sabe Volcanic area beyond Pacheco Pass includes at least 13 significant peaks further south in the Diablo Range as viewed from the Lawler Ranch. Parts of Lawler Ranch, Henry W. Coe State Park, and The Nature Conservancy’s Romero Ranch conservation easement area are within the proposed inundation area of the new Pacheco dam and reservoir expansion project. Photo: Scott Hein
