Question

If 20% of the reservoir capacity is earmarked for dead storage in a storage reservoir of 30 M.cum and the average annual silt deposition in the reservoir is 0.1 M cum, then the useful life of the reservoir will start reducing after ____________

(a) 60 years

(b) 120 years

(c) 240 years

(d) 300 years

I had been asked this question in unit test.

Question is from Reservoir Losses topic in division Reservoirs and Dam Reservoirs Planning of Irrigation Engineering

Answer 1

Correct answer is (a) 60 years

The best explanation: Given, Reservoir capacity = 30 M.cum

Dead storage is 20% of the reservoir capacity = 0.2 x 30 = 6 M.cum

Time during which 6 M cum is filled by sediment @0.1 M.cum/yr = 6/0.1 = 60 years.