Determine the water distribution efficiency (ηd) of an irrigated field where the mean depth of water stored is 1.5 cm and the mean absolute deviation from the mean depth is 0.1 cm.

Determine the design discharge at the outlet of a canal, the culturable command area of which is 1000 hectares. The cropping intensities of sugarcane and wheat are 30% and 40%, respectively. The duties of each crop at the head of the canal are 850 hectares/cumec and 1500 hectares/cumec, respectively.

In a tile drainage system, the height of the water table above the impervious layer is 9 m, the depth of the impervious stratum below the center of drains is 8 m, and the permeability coefficient is 0.001 cm/s. The total discharge per unit length carried by the drain is q = 0.75 S8.64 × 106 m3/s/m. Calculate the spacing (S) of the tile drain.