Overview
- Prosecutors say Gregory Arnoldi Jr. and Gregory Arnoldi Sr. pleaded no contest in October 2026 to felony vandalism and misdemeanors for water pollution and stream alteration and were each sentenced to 30 days in county jail and fined $8,135.
- The Sierra County District Attorney placed both men on three years of felony probation and barred them from mining during that period to prevent new unpermitted activity.
- Officials found the pair used heavy equipment to alter a historic carriage route and build an illegal dirt road near Keystone Creek, sending rock and soil into the creek that feeds the North Fork of the Yuba River.
- The court ordered the defendants to design and pay for restoration of damaged public and private lands by Aug. 1, 2027, and warned that failure to meet that deadline would trigger an extra eight months in jail and more than $30,000 in added fines.
- The case began after a California Department of Fish and Wildlife referral and highlights the tension between Sierra County’s Gold Rush heritage and modern permitting and environmental laws that require reclamation plans and notification before altering streams.