Question

The table below shows the salmon population, in thousands of pounds, in Columbia River, from 1870 to 1950.

Year Salmon population (in thousands of pounds)
1870 10,200
1890 20,000
1915 20,500
1931 30,000
1950 10,000
Based on the table, which of these is most likely the period during which a series of large hydropower units were built on the Columbia River?

A. between 1870 and 1890

B. between 1890 and 1915

C. between 1915 and 1931

D. between 1931 and 1950

Answer 1

D because there was a becrease which means that the hydropower units were in the way of the fish

Answer 2

Option D, between 1931 and 1950

Step-by-step explanation:

The hydraulic structure of dam has some sub structures which interferes with the natural navigation of the fishes within any water body.

Due to such interference the fishes get diverted to a different path of flow and hence are not accountable. This causes reduction in the number of fish counts.

The higher the construction of dams, the higher will be the effect of it on the fish navigation which will ultimately lead to reduction in fish count.

Hence, option D is correct.