List of top Irrigation and Drainage Engineering Questions asked in GATE AG

The most economical trapezoidal channel section with 1:1 (horizontal:vertical) side slope is designed to carry a maximum of 40 cm depth of water at its full capacity. The bed slope of the channel is 1:2500 and the Manning's roughness coefficient of channel section is 0.01. The estimated discharge capacity of the channel in m\(^3\).s\(^{-1}\) is \(\underline{\hspace{1cm}}\) (round off to 2 decimal places).

A pump delivering 80 L/s irrigates 2 ha in 10 h. Soil moisture increases from 18% to 30% in a 50 cm root zone. Soil bulk density is 1500 kg/m\(^3\). Compute water application efficiency (round off to two decimals).

A pumping test pumps 5400 L/min for 24 h from a well. Observation wells at 30 m and 90 m show drawdowns of 1.11 m and 0.53 m. Well diameter = 30 cm. Estimate drawdown in the pumped well (round off to 2 decimals), using steady–state flow and \(\pi = 3.14\).

Given: Mg\(^{2+}\)=5.68 meq/L, Na\(^{+}\)=9.90 meq/L, HCO\(_3^{-}\)=11.20 meq/L. \[ \frac{\text{HCO}_3^-}{\text{Ca}^{2+}}=2.8 \] Find Sodium Adsorption Ratio (SAR).