Malakoff Diggins State Historic Park

As part of The Sierra Fund’s (TSF) work to protect public health and restore ecosystem resiliency from abandoned mine lands, The Sierra Fund advocates for and provides resources to State Parks of California to clean up Malakoff Diggins State Park. This historic hydraulic mine site continues to this day to discharge mercury and sediment into Humbug Creek which feeds the Yuba River. Cleaning up (remediating) the park is critical to the health and welfare of communities and ecosystems.

Malakoff Diggins was Once the World’s Largest Hydraulic Mine

Malakoff Diggins State Historic Park is a hydraulic mine site in Nevada County that was never cleaned up and has contributed mercury and suspended solids into Humbug Creek and the Yuba River. Hydraulic mining power-washed away the gravels of ancient rivers and laced the gravels with liquid elemental mercury during gold extraction practices. The mercury left behind continues to bioaccumulate and biomagnify within the food web, exposing humans and wildlife to a dangerous neurotoxin over 100 years later. Hydraulic mine sites release sediment and mercury and are a significant predictive variable for fish mercury concentration in downstream water bodies (Alpers et al., 2016). The historic 2 x 1-mile hydraulic mine pit is the centerpiece of California’s Malakoff Diggins State Historic Park and is on the National Register of Historic Places.

historic photograph of monitors being used to erode the mountainside in a pit at Malakoff Diggins

TSF’s Report Documented Malakoff’s Discharge and the Best Remediation Options

In April 2015, The Sierra Fund published the findings of the first four years of TSF monitoring water quality below Malakoff Diggins. The report is titled the Humbug Creek Watershed Assessment and Management Recommendations Report. This report offered best practices and strong options for remediation to California State Parks and its subcontractors to help them determine an approach to site remediation. In addition, this report created a model for scientific assessment of hydraulic mines and multidisciplinary collaboration that could be replicated at similar sites across California.

The Sierra Fund Monitors Ongoing Discharge and Is Committed to Seeing this Park Site Cleaned Up

The good news is that after years of advocacy, State Parks finally got money to do a full environmental review and are ready to implement remediation actions. Sadly, state action remediating Malakoff Diggins remains slow and incompleteOur sustained work to keep the momentum moving to implement the Malakoff remediation project is needed. Particularly – our water quality monitoring.

The Sierra Fund maintains the longest operating stream gauge at the site, measuring turbidity and discharge every 15 minutes year-round. TSF staff coordinate annually with State Parks and their subcontractors and share our data on mercury and sediment discharged from the mine site. This ongoing monitoring is one of the best tools California possesses to measure the success of Malakoff Diggins’s remediation efforts. The Sierra Fund is committed to ongoing monitoring and working with State Parks to ensure effective remediation is achieved.

We envision a day when Malakoff Diggins State Park is not only a flagship state park providing enriching education on the history of the gold rush – but also a park telling the story of how a community came together to remediate this site and greatly reduced ongoing impacts to our water quality for the benefit of nature and our communities.

person in waders testing water flow in a creek