does this process affect the environment?
Yes, it effects riparian natural environment and agricultural systems.
Hydraulic mining
While generating millions of dollars in tax revenues for the state and supporting a large population of miners in the mountains, hydraulic mining had a devastating effect on riparian natural environment and agricultural systems in California. 
what is the time period of the middle ages? 5th to the late 15th century which was the most powerful empire of the time? The Roman Empire which religion spread during this time period? Islam was any civilization destroyed during this time? UNANSWERABLE what was the language commonly spoken in the empire mentioned above? Latin what was the status of women in that civilization? Freeborn Roman women were considered citizens but did not vote, hold political office, or serve in the military. what sort of mining was done there? Hydraulic mining is it done in any other country? Yes, Australia and New Zealand
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Hydraulic mining [SEP] Environmental consequences
While generating millions of dollars in tax revenues for the state and supporting a large population of miners in the mountains, hydraulic mining had a devastating effect on riparian natural environment and agricultural systems in California. Millions of tons of earth and water were delivered to mountain streams that fed rivers flowing into the Sacramento Valley. Once the rivers reached the relatively flat valley, the water slowed, the rivers widened, and the sediment was deposited in the floodplains and river beds causing them to rise, shift to new channels, and overflow their banks, causing major flooding, especially during the spring melt.