What year did the significant decline in water quality due to hydraulic mining debris end?

The significant decline in water quality due to hydraulic mining debris is historically linked to the practices that were prevalent during the Gold Rush era, particularly in California. Hydraulic mining began in the 1850s and led to severe environmental degradation, including sedimentation of waterways and contamination of water sources. The legal and societal backlash against these practices culminated in the Sawyer Decision in 1884, which effectively restricted hydraulic mining practices.

This decision marked a turning point and initiated a decline in the input of mining debris into California's rivers and streams. By implementing regulations on hydraulic mining, the impact on water quality began to lessen, and the ecosystem had a chance to recover over subsequent years. Therefore, 1884 is significant as it represents the end of a critical period in which water quality was severely impacted by mining activities, leading to improved conditions in California's waterways thereafter.

The other years listed do not correlate with the established timeline of regulatory change related to hydraulic mining and its impact on water quality.