# GATE Questions & Answers of Irrigation Civil Engineering

#### Irrigation 19 Question(s) | Weightage 08 (Marks)

A 1:50 model of a spillway is to be tested in the laboratory. The discharge in the prototype spillway is 1000 m3/s. The corresponding discharge (in m3/s, up to two decimal places) to be maintained in the model, neglecting variation in acceleration due to gravity, is ______

The intensity of irrigation for the Kharif season is 50% for an irrigation project with culturable command area of 50,000 hectares. The duty for the Kharif season is 1000 hectare/cumec. Assuming transmission loss of 10%, the required discharge (in cumec, up to two decimal places) at the head of the canal is _____

Group I contains three broad classes of irrigation supply canal outlets. Group II presents hydraulic performance artributes.

 Group I Group II P. Non-modular outlet 1. Outlet discharge depends on the water levels in both the supply canal as  well as the receiving water course Q. Semi-modular outlet 2. Outlet discharge is fixed and is independent of the water levels in both the supply canal as well as the receving water course R. Modular outlet 3. Outlet discharge depends only on the water level in the supply canal

The correct match of the items in Group I with the items in Group II is

The culturable command area of a canal is 10,000 ha. The area grows only two crops-rice in the Kharif season and wheat in the Rabi season. The design discharge of the canal is based on the rice requirements, which has an irrigated area of 2500 ha, base period of 150 days and data of 130 cm. The maximum permissible irrigate area (in ha) for wheat, with a base period of 120 days and delta of 50 cm, is _________

A concrete gravity dam section is shown in the figure. Assuming unit weight of water as 10 kN/m3 and unit weight of concrete as 24 kN/m3, the uplift force per unit length of the dam (expressed in kN/m) at PQ is _________

The two columns below show some parameters and their possible values.

 Parameter Value P – Gross Command Area I –100 hectares/cumec Q – Permanent Wilting Point II – 6o C R – Duty of canal water III – 1000 hectares S – Delta of wheat IV – 1000 cm V – 40 cm VI – 0.12

Which of the following options matches the parameters and the values correctly ?

A field channel has cultivable commanded area of 2000 hectares. The intensities of irrigation for gram and wheat are 30% and 50% respectively. Gram has a kor period of 18 days, kor depth of 12 cm, while wheat has a kor period of 18 days and a kor depth of 15 cm. The discharge (in m3/s) required in the field channel to supply water to the commanded area during the kor period is _______.

The average surface area of a reservoir in the month of June is 20 km2. In the same month, the average rate of inflow is 10 m3/s, outflow rate is 15 m3/s, monthly rainfall is 10 cm, monthly seepage loss is 1.8 cm and the storage change is 16 million m3. The evaporation (in cm) in that month is :

Irrigation water is to be provided to a crop in a field to bring the moisture content of the soil from the existing 18% to the field capacity of the soil at 28%. The effective root zone of the crop is 70 cm. If the densities of the soil and water are 1.3 g/cm3 and 1.0 g/cm3 respectively, the depth of irrigation water (in mm) required for irrigating the crop is ________

The ratio Nf/Nd is known as shape factor, where Nf is the number of flow lines and Nd is the number of equipotential drops. Flow net is always drawn with a constant b/a ratio, where b and a are distances between two consecutive flow lines and equipotential lines, respectively. Assuming that b/a ratio remains the same, the shape factor of aflow net will change if the

The transplantation of rice requires 10 days and total depth of water required during transplantation is 48 cm. During transplantation, there is an effective rainfall (useful for irrigation) of 8 cm. The duty of irrigation water (in hectares/cumec) is:

Wheat crop requires 55 cm of water during 120 days of base period. The total rainfall during this period is 100 mm. Assume the irrigation efficiency to be 60%. The area (in ha) of the land which can be irrigated with a canal flow of 0.01 m3/s is

The moisture holding capacity of the soil in a 100 hectare farm is 18 cm/m. the field is to be irrigated when 50 percent of the available moisture in the root zone is depleted. The irrigation water is to be supplied by a pump working for 10 hours a day, and water application efficiency is 75 percent. Details of crops planned for cultivation are as follows:

 Crop Root zone depth (m) Peak rate of moisture use (mm/day) x 1.0 5.0 y 0.8 4.0

The capacity of irrigation system required to irrigate crop 'X' in 36 hectares is

The moisture holding capacity of the soil in a 100 hectare farm is 18 cm/m. the field is to be irrigated when 50 percent of the available moisture in the root zone is depleted. The irrigation water is to be supplied by a pump working for 10 hours a day, and water application efficiency is 75 percent. Details of crops planned for cultivation are as follows:

 Crop Root zone depth (m) Peak rate of moisture use (mm/day) x 1.0 5.0 y 0.8 4.0

The area of crop 'Y' that can be irrigated when the available capacity of irrigation system is 40 liters / sec is

An agricultural land of 437 ha is to be irrigated for a particular crop. The base period of the crop is 90 days and the total depth of water required by the crop is 105 cm. If a rainfall of 15 cm occurs during the base period, the duty of irrigation water is

The base width of an elementary profile of gravity dam of height H is b. The specific gravity of the material of the dam is G and uplift pressure coefficient is K. the correct relationship for no tension at the heel is given by

An outlet irrigates an area of 20 ha. The discharge (l/s) required at this outlet to meet the evapotranspiration requirement of 20 mm occurring uniformly in 20 days neglecting other field losses is