Protect Cache Creek from Gravel Mining
The world’s largest cement company and a major climate pollutor – CEMEX – has applied to Yolo County for a permit to extend its mining operations along Cache Creek near the farm worker town of Madison for another 20 years until 2047.
CEMEX, an $18 billion company, wants to mine an additional 20 million tons of sand, gravel and rock from the lower Cache Creek floodplain to use in major construction projects such as dams, highways and urban sprawl.
Instead of restoring their mercury-contaminated mining pits by 2032, CEMEX is asking to delay the reclamation of the 1,900 acre (approx 3 square miles) site to 2052.. They are also substantially changing the reclamation plan.
Instead of restoring wetlands to this critical riparian floodplain, CEMEX is proposing a combination of farmland, habitat and “lake features.” Yet promises to protect nature from mercury poisoning in the open impoundment pits have already been broken and farmland restoration is, according to local farmers, “not good.”
Over 90% of the Sacramento Valley’s carbon rich, life-enhancing wetlands have been destroyed by unsustainable development. Climate change is causing widespread flooding, drought, higher temperatures and a rise in mosquito-born diseases. A livable future hangs in the balance.
Cache Creek — a unique wildlife corridor connecting the outer coastal mountains and the valley –has some of the greatest potential to restore nature in Yolo County. It is a critical lifeline for our regional climate adaptation priorities.
On Tuesday, December 9, 2025 at 9am, the Yolo County Board of Supervisors will hold a public hearing and vote on this project. The hearing will take place in Woodland, 625 Court Street, Room 206. Written comments can be emailed to clerkoftheboard@yolocounty.gov.
Loss of Nature
Cache Creek has the potential to become the environmental backbone of Yolo County. Originating from Clear Lake, the creek flows from the inner coastal mountains through Capay Valley after which its waters once fanned out across the valley floor and joined with the mighty Sacramento River.
Less than 200 years ago, the watershed sustained vast wildlife populations and natural abundance. It was known by the late Wintun elder Bertha Nye Norton as kaltipookapai schlombeck, or “gathering wealth creek.” Rich plant and animal life supported the lifeways of the Puhtwin-Wintun people for thousands of years.
Salmon, sturgeon, lamprey, elk, deer, pronghorn, California grizzly bear, beaver, river otter, ring-tailed cats, mountain lions, bobcats, turtles, raptors, and myriad invertebrates all made their home in the verdant riparian area that spanned for a mile along either side of Cache Creek. Dense forests of cottonwoods and oaks gave the town of “Woodland” its name.
In the 1850’s Cache Creek became the site of the first irrigated-water diversion project in the newly established state of California. Gravel mining in the creek bed began later that century and was so prolific that gravel from Cache Creek was hauled from the town of Madison by rail and used to build the city of San Francisco after the 1906 earthquake.
After nearly 200 years of human exploitation, the creek is gradually making an environmental comeback. Hundreds of people are working day in and day out to administer CPR—Conservation, Preservation, Restoration—to restore nature to this vital, deeply imperiled watershed.
Climate Impacts
The CEMEX mine uses massive diesel-fueled earth-moving equipment to dig up the sand and gravel on site and then generates over 50,000 truck trips a year to deliver the material to construction projects throughout Northern California. These trips add more than 3,000,000 vehicle miles traveled (VMT) to the county’s carbon footprint.
Yolo County declared a climate emergency in 2022 to put in motion a just transition to a carbon neutral county by 2030. Hundreds of Yolo County residents, community-based organizations, the Yolo County Resource Conservation District, local farmers, the Yocha Dehe Tribe, UC Davis and many others collaborated on a new Climate Action and Adaptation plan that was released in Nov. 2024. This award-winning plan outlines 180 detailed actions to curtail climate change and build resilient communities.
Instead of aligning their project with Yolo County’s climate goals, the CEMEX Subsequent Environmental Impact Report provides ZERO specifc mitigation measures for its greenhouse gas emissions. Instead, CEMEX says they will create a “GHG Emissions Reduction Plan” AFTER thte on this project.eir permit has been secured.
Furthermore, the mine is in a FEMA-designated Floodway where development that could interfere with the rapid flow of floodwaters is prohibited. Risks to upstream Capay Valley communities and downstream Woodland from climate-induced flash floods brought on by atmospheric river storms has not been adequately assessed or disclosed to local communities, who are predominantly low-income farmworkers. The predominantly low-income, farmworker town of town of Madison already floods on a regular basis.
Climate resilience should be a top priority, not risky mega-development projects like deep pit gravel mining. Local creekside residents, habitat restoration and climate adaptation experts are advocating for the restoration of the natural floodplain, but this alternative vision was not evaluated in the project EIR.
Methyl Mercury Toxicity
CEMEX and other companies along Cache Creek are mining way below the groundwater table. As the 70+ foot deep pits fill with groundwater, methyl mercury, an extremely potent neurotoxin, is being generated by bacteria that thrive in anaerobic conditions.
Mercury is bioaccumulating to toxic levels in fish and can potentially cause serious health problems if the fish are ingested by wildlife or humans.
Over five years ago, the county’s mercury consultant – Darryl Slotton – recommended that “lake management plans” be developed to address the problem. These plans haven’t yet been created, let alone implemented.
The Sierra Club has called out the county’s noncompliance with its own mercury regulations and is demanding these violations be addressed before any new permits are granted. See:
Loss of Prime Farmland
The CEMEX project proposes to fill in two of the wet pits along Cache Creek and return them to agriculture. Before they mine the gravel, they remove the topsoil and stockpile it alongside the mine where it can sit for decades. Eventually, they return this topsoil to the mined out pits.
Previous mining projects have shown that the so-called “reclaimed” farmland has never been brought back to pre-mining productive standards in terms of crop yields expected from prime farmland. At best the “reclaimed” farmland has resulted in smaller yields of lower-quality crops.
Some organic farmers have had to stop farming organically and resort to conventional, chemical-intensive measures to boost yields. It is commonly known that mining companies have had to pay farmer’s to farm reclaimed areas to comply with their reclamation obligations.
Local Cache Creek residents are calling for the mined-out area along the creek to be incorporated into an expanded floodplain rather than returned to agriculture with dubious results.
This alternative was not evaluated in the recent EIR despite the significant environmental benefits it would bring.
Groundwater Sustainability
The Yolo Subbasin Groundwater Sustainability plan calls for the protection of groundwater-dependent ecosystems along Cache Creek.
Protections are needed to ensure the availability of groundwater for local farming and domestic needs.
Many farmers had their wells dry up during the last drought. The wetland at the Cache Creek Nature Preserve also went dry.
As the late Yolo County Supervisor Gary Sandy stated during the approval of the Teichert-Shiffler mine in 2022, it is “reckless” to approve a thirsty mining project that will permanently impact the aquifer.