The correct answer to this open question is the following.
Although there are no options attached we can say the following.
The gold rush in California brought a sudden influx of humans into the territory. Describe the environmental impact of the gold rush from water usage to land alteration.
Indeed, the environment was really affected by the gold rush activity in California. We could say that it heavily impacted the territory and devastated the environment of the region.
Gold mining was the activity that probably created the most negative impact on the land.
In the 1850s, the technology used in hydraulic mining devastated the woods. The construction of a dam in the region of Nevada County changed the course of the rivers and this was so destructive to the ecology of the place. The impact on agriculture activities was hard.
Another problem or huge impact was lumbering. The mines needed wood to built canals and wood was also used as fuel. Sequoia trees were affected.