Section A
Q1.
(a)
The annual rainfall of six different raingauge stations of a river basin is 136.70 cm, 102.90 cm, 98.80 cm, 180.30 cm, 82.60 cm and 110.30 cm.
Determine :
(i) The standard error in the estimation of average rainfall of the six raingauge stations.
(ii) The optimum number of raingauge stations in the river basin for a 10% error in the estimation of average rainfall.
(b) A 1.3 m wide rectangular channel had 0.35 m depth of water at a certain section of the channel. The flow discharge through the channel is 2.0 cumecs. Determine whether the hydraulic jump will take place or not. Find the height of jump and loss of energy.
(c)
Find out the power required to drive the centrifugal pump if it lifts water to a height of 22 m. The overall efficiency of the pump is 70%. The pipe diameter is 10 cm and length is 100 m. It delivers 1500 l/min as discharge with the coefficient of friction of pipe as 0.004 and gamma as
ho g (1000 imes 9.81).
(d)
A PST 15 m long, 6 m wide and 3 m deep treats water for a town with a population of 20,000 supplied with 100 lpcd. The raw water sample indicated suspended solids conc. as 60 ppm. The PST worked with efficiency of 70% SS removal and the average specific gravity of the deposit in PST was 2. Compute
(i) Detention Time
(ii) Horizontal Velocity
(iii) Rate of dry solids deposited
(iv) Overflow rate.
(e) Discuss the impact of heavy metals in industrial wastewater when disposed into surface water. With the help of sketches, explain the working principle of the two methods used for removal of heavy metal from industrial wastewater.
