22. The density of population over 40 hectares is 250/hectare. If water supply demand per day is 200 litres and sewage discharge is 80% of water supply, the sewage flow in sewers of separate system, is

A. 0.05552 cumec

B. 0.05554 cumec

C. 0.05556 cumec

D. 0.0556 cumec

23. The drainage area of a town is 12 hectares. Its 40% area is hard pavement (K= 0.85), the 40% area is unpaved streets (K = 0.20) and the remaining is wooded areas (K = 0.15). Assuming the time of concentration for the areas as 30 minutes and using the formula P., = + the maximum run t 90060 off is

A. 0.10 cumec

B. 0.12 cumec

C. 0.15 cumec

D. 0.20 cumec.

24. Pick up the correct statement from the following :

A. The water supply pipes carry pure water free from solid particles

B. The water supply pipes get clogged if flow velocity is less than self cleansing velocity

C. The sewers may be carried up and down the hills and valleys

D. The sewer pipes are generally laid along level hills

25. The sewer pipes

A. carry sewage as gravity conduits

B. are designed for generating self-cleansing velocities at different discharge

C. should resist the wear and tear caused due to abrasion

D. all the above.

26. -3 rd or -4 th extra space is left in sewer pipes at maximum discharge for

A. low estimates of the average and maximum flows large scale infiltration of storm water

B. unexpected increase in population

C. all the above.

D.

27. If the peak discharge of a storm water drain (S.W. Drain) is expected to exceed 150 cumecs, the free board to be provided, is

A. 100 cm

B. 90 cm

C. 80 cm

D. 50 cm.

28. The Chezy's constant Gin the formula V= C:lit-'s depends upon

A. size of the sewer

B. shape of the sewer

C. roughness of sewer surface

D. all the above.

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