SHOTS - HYDROLOGY & IRRIGATION

🔥 Border flooding is used on rolling land. 

🔥 Delta=(8.64B/D). 

🔥 The duty is largest on the field. 

🔥 The ‘outlet discharge factor’ is the duty at the head of water course. 

🔥 Water application efficiency is the ratio of water stored in the reservoir to the water delivered in the field. 

🔥 Useful water for plant growth is capillary water. 

🔥 consumptive irrigation requirement The amount of irrigation water required to meet the evapotranspiration needs of the crop during its full growth 

🔥 Hydrograph is the graphical representation of runoff and time. 

🔥 Soil moisture deficiency-the depth of the water required to bring the soil moisture content to the field capacity. 

🔥 Cyclonic precipitation is caused due to the lifting of an air mass due to the pressure difference. 

🔥 Convective precipitation is caused due to the temperature difference. 

🔥 Simons rain gauge is the non recording rain gauge. 

🔥 Tipping bucket type of rain gauge is used in inaccessible areas. 

🔥 Convex water surface will give highest rate of evaporation. 

🔥 A current meter is used for measuring the velocity of flow of water. 

🔥 An artesian aquifer is the one where water is under pressure between two impervious strata. 

🔥 A deep well has more discharge than shallow well. 

🔥 The useful storage is the volume of water stored between minimum pool level and normal pool level. 

🔥 Trap efficiency of a reservoir is a function of capacity/inflow ratio. 

🔥 The major resisting force in a gravity dam is self weight of the dam. 

🔥 When the reservoir is full the maximum compressive force in a gravity dam is produced with in the middle third of base. 

🔥 The elementary profile of a gravity dam is a right angled triangle. 

🔥 The maximum permissible eccentricity for no tension at the base of gravity dam is B/6. 

🔥 For wave action in gravity dams the maximum height of freeboard is generally taken 1.25hw. 

🔥 Seepage through embankment in earthen dam is controlled by drain trenches. 

🔥 Ogee spillway is least suitable for earthen dam. 

🔥 In chute spillway the flow is usually super critical. 

🔥 A divide wall is provided at right angle to the axis of weir. 

🔥 Silt excluder is constructed on river bed upstream of head regulator. 

🔥 Contour canal-canals run parallel to the contours of the country. 

🔥 Side slope canal-canals run perpendicular to the contour of the country. 

🔥 Garrets diagram is used in Kennedys theory. 

🔥 According to lacey’s theory the eddies are generated from bottom as well as sides. 

🔥 Canal escape is used to remove surplus water. 

🔥 Kennedy’s gauge outlet is flexible outlet. 

🔥 Montague type fall is parabolic glacis. 

🔥 Meter fall is a vertical drop fall. 

🔥 Rigid module is constant discharge. 

🔥 Flexibility-the ratio of rate of discharge of an outlet to the rate of change of discharge of distributing channel. 

🔥 An aggrading river is a silting river. 

🔥 Scouring river is degrading river. 

🔥 River training is achieved by groynes and bandalling. 

🔥 A repelling groyne is pointing upstream. 

🔥 A river training work is generally required when the river is meandering. 

🔥 Cetyl alcohol is used in water surface to reduce the evaporation. 

🔥 In linear reservoir storage varies linearly with outflow rate. 

🔥 1 gauge for 520km^2 in plain areas, 

🔥 1 gauge for 260km^2 in 1000m elevation about mean sea level 

🔥 1 gauge for 130km^2 in hilly areas. 

🔥 The double mass analysis is adopted to check the consistency of data. 

🔥 In upstream slope of an earthen dam the most critical condition is sudden draw down condition. 

🔥 Permanent wilting point is a soil characteristic. 

🔥 Mean precipitation over an area is best obtained by orographical isohyetal method.