Hardin County: Turning Wood Waste into Climate Action
Our flagship site in Hardin County, Texas, is transforming waste wood into permanent carbon capture and restored land.
Why Hardin County?
Hardin County is an ideal site for CSI’s carbon capture work thanks to its unique natural features and strategic location. The area sits atop the Lissie Formation, an ancient river delta with dense, high-plasticity clay that naturally seals our underground vaults and protects them from water and oxygen. Surrounded by East Texas forests, Hardin County offers abundant wood waste resources and a landscape ready for ecological restoration. Its combination of geological suitability and environmental potential makes it a showcase for innovative, sustainable land use.
Vault Stabilization & Site Integrity
How We Ensure Long-Term Stability at Hardin County
Throughout 2023, CSI constructed and stabilized four wood vaults at the Hardin site, following a careful process of excavation, biomass loading, and clay sealing. The team used native reserve clay for stabilization, especially after heavy rainfall events, which caused minor surface depressions. These were quickly addressed by adding and compacting more clay, ensuring the vaults remained secure and weather-resistant.
By the end of 2023, excess clay was sculpted and smoothed over the vaults, and a gas monitoring system was installed to track vault integrity. Regular measurements, including those taken in March 2024, confirmed that all vaults are covered by the required clay thickness and remain stable.
While some superficial cracks appeared in the clay caps during dry, warm periods, these did not extend deeper than 10 inches. Below this, the clay remains moist, dense, and structurally sound-demonstrating the effectiveness of the sealing and stabilization process. Ongoing monitoring shows no significant voids or failures, confirming the site’s long-term stability and the security of the stored carbon.
Why Hardin’s Clay Makes Long-Term Carbon Storage Possible
The secret to our vaults’ durability lies beneath your feet. Hardin County’s land is layered with dense, high-plasticity clay from the ancient Lissie Formation. While the topsoil here is thin, the underlying clay is exceptionally thick and watertight-perfect for sealing our underground vaults and locking out both water and oxygen.
This natural clay barrier means we never need to use plastic liners, making our process more sustainable and environmentally friendly. The clay’s unique properties not only keep the stored wood isolated from the elements but also help stabilize the vaults through Texas’s cycles of rain and drought. Scientific studies show that carbon buried in deep, dense subsoils like these remains far more stable and isolated from the atmosphere for decades or even centuries.
By working with Hardin’s natural geology, we’re able to create a long-lasting, nature-based solution for carbon removal-one that supports both climate action and healthy, living soils.
Roads to the Future
Getting to biomass isn’t always easy. Creating roads to access biomass is sometimes necessary, but CSI utilizes temporary roads to let Nature get back to doing what it does best after we’re gone - being wild and beautiful.