Hydrualic Mines Inventory

With partners at the Tahoe National Forest (TNF) and graduate students from California State University, Chico, The Sierra Fund has begun to delineate hydraulic mines and mine features within the Tahoe National Forest boundary using LiDAR. This information will be used in conjunction with other geospatial data including delineations of forest and fuels treatment projects that are planned or underway, locations of water bodies and roads, and the LiDAR derived EcObject Vegetation Map of fuel types and loads in order to create a database of priority sites for mercury abatement.

“The Sierra Fund’s efforts to compile relevant data and build a hydraulic mine and mine feature inventory are intended to facilitate the identification and prioritization of future mine remediation projects to increase the pace and scale of this work.”

Nick Graham, M.S., Environmental Scientist

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To date there is no one database that encompasses the totality of hydraulic mines within the Sierra Nevada. Currently, the extent of the database(s) of hydraulic mines is comprised of the following sources; Topographic Mine Symbols (TOMS) by the Department of Mine Reclamation, Principle Areas of Mine Pollution (PAMP) by the Division of Mines and Geology, and mine sites described in a United States Geological Survey (USGS) paper, Gold-bearing gravel of the ancestral Yuba River. The Sierra Fund views the lack of a singular comprehensive list of hydraulic mine sites in the Sierra as a major barrier to addressing the legacy mercury contamination issue in the State.


The Sierra Fund has generated hydraulic mines delineations within the Tahoe National Forest LiDAR dataset. The Sierra Fund has started prioritization and inventory work on a subset of delineated mines on Tahoe National Forest, located within a 31,000 acre TNF planning project area called the Trapper Project. The Sierra Fund has begun to develop attributes for each of the hydraulic mines in this area and established a preliminary prioritization based on the following criteria; (1) USDA Forest Service Ownership; (2) National Historic Preservation Act Section 106 determination; (3) Feature size (>10 acre); (4) Fuels treatment proposed; (5) Proximity to roads; (6) Fire risk level. Additional attributes are currently in development for the database, ideas include proximity to threatened and endangered species habitat, volume of sediment exhumed, years operated, amount of mercury used at the site, and amount of gold extracted from the site. The overarching rationale is that the hydraulic mines and their features can be prioritized many different ways depending on the goals and objectives of remediation efforts.


There are over 40,000 abandoned mine lands in California, many of which have both physical and chemical hazards associated with them. In an effort to make the daunting task of remediating these sites more manageable and more strategic The Sierra Fund has focused our inventory development to address the impacts of one type of mining (hydraulic mining) and one type of contaminant (mercury). By developing an inventory and prioritization tool of hydraulic mines and mine features within the Sierra Nevada, The Sierra Fund hopes to increase the pace and scale of hydraulic mine remediation.

Next Steps

The Sierra Fund will continue to delineate hydraulic mine sites and mine features within the Sierra as new LiDAR data becomes available. Additionally, steps will be made to consolidate and make consistent the attributes between data sources to facilitate the development of the prioritization tool. Finally, The Sierra Fund will create an online repository to host and publish the hydraulic mine and mine feature inventory on a web-based format that will be publicly available.

Project Funders

Resources Legacy Fund
Bella Vista Foundation