A2 - Recalled 1 (2015) Flashcards
Minimum trajectory angle of sprinkler
10-25 degrees
allowable percentage depletion of most crops
50%
soil moisture tension with 15 atmosphere
permanent wilting point
the ratio of water beneficially used on the project, farm, or field to the amount of water delivered to the farm
water use efficiency
basic irrigation method for lowland farming
basin irrigation
irrigation method with high cost but low operation cost
overhead irrigation
irrigation method wherein water is directed to the base of the plant and is applied to the soil through small orifice
drip or trickle irrigation
laterals enter the submain from one side only to minimize the double drainage that occurs near the submain
gridiron layout
depth of shallow tube well
20 m or 60 ft
equation for evapotranspiration computation
penman-montieth equation
precipitation results from mechanical lifting of air mass over mountain barriers
orographic rainfall
travels over the ground and through the channels to reach the outlets
runoff
a hydrograph with a unit volume of direct runoff for a given storm duration
unit hydrograph
combination of splash and sheet erosion
interrill
flow greater than the critical flow
supercritical flow
type of flow wherein the discharge or flow in a prismatic channels is constant with respect to time
steady flow
irrigation components, related to flow and head
head gates
uses a thin wall of plastic, butyl, concrete, steel or wood to barrier against seepage through the wall
full diaphragm type
type of precipitation in the philippines
rain
referred to as rainfall
precipitation
standard height of an earth embankment
not exceeding 15 meters
an instrument used to determine the wind speed
anemometer
measures atmospheric humidity
hygrometer
A mathematical expression for the macroscopic flow of water through a porous system. It says that the discharge rate q is proportional to the gradient in the hydraulic head and the hydraulic conductivity
Darcy’s law
the composite parts of the irrigation system that divert water from natural bodies of water such as rivers, streams, and lakes.
headworks
a thin film of soil layer detached and transported by water flowing on the land surface.
sheet erosion
the type of surveying in which the surface of the earth is considered as a plane, or in which its spheroidal shape is neglected, with regard to horizontal distances and directions.
plane surveying
the recommended pressure head variation in the lateral between the first and last sprinkler
20%
what is the formula for the universal soil loss equation
E = RKLSCP
Values of the USLE
E - annual soil erosion rate
R - rainfall-runoff erosivity factor
K - soil erodibility factor
L - slope length factor
S - slope factor
C - cover and crop management factor
P - erosion control practices or conservation practice factor
soil property which describes the ability of the soil to transmit water
hydraulic conductivity
the surface is rarely wet since the water is supplied from the soil underneath. This requires complete control of the water table so that the root zone is kept relatively free of excess water but is continually supplied with capillary moisture during the cropping season.
sub-irrigation
what do you call the mountain side, with reference to the wind direction in which the air masses passing through it are cold and dry.
leeward
the equation used in current meters is V=a+bN. what does “a” signifies?
starting velocity
a type of survey that deals with the contour of the surveyed location
topographic surveying
a type of geological formation underground that is a saturated formation of the earth. It not only stores the water but also yields it in adequate quantity. Main source of groundwater application.
aquifer
an aquifer which has free water surface- which means the water table exists for this type of aquifer.
unconfined aquifer
an aquifer that is trapped between 2 impermeable beds. The water in this type of aquifer will be under greater pressure which is greater than atmospheric pressure.
confined aquifer
a saturated formation that permits water through it but does not yield water in sufficient quantity. Sandy clay is a n example of this formation.
aquitard
a geological formation which is impermeable to the flow of water. It contains a large amount of water in it but does not permit water through it and also does not yield water.
aquiclude
an impermeable geological formation which is neither porous nor permeable- which means it cannot store water in it and at the same time it cannot permit water through it.
aquifuge
Water storage: yes
permeability of water: permeable
yield of water: yes
transmit: yes
aquifer
Water storage: yes
permeability of water: party permeable
yield of water: yes, but slow yielding
transmit: yes
aquitard
Water storage: yes
permeability of water: impermeable
yield of water: do not yield
transmit: no
aquiclude
Water storage: no
permeability of water: impermeable
yield of water: do not yield
transmit: no
aquifuge
type of surveying in which the mean surface of the earth is considered as a plane and the spheroidal shape is neglected
plane surveying
type of surveying in which the shape of the earth is taken into account
geodetic surveying
for the preparation of maps of large extents of territory
trigonometrical surveying
a type of survey determines the relative locations of points (places) on the earth’s surface by measuring horizontal distances, differences in elevation and direction
topographic surveying
the science of measurement and description of features which affect maritime navigation, maritime construction, dredging, offshore wind farms, and other related activities.
hydrographic surveying
pump used on shallow tube well
centrifugal or jet pumps
flow of water to the propeller of the propeller pump
axial
forms in the aquifer around a pumping well as the water level decline
pumping cone
it is the bouncing of sand grains as they are picked up, carried along, and dropped repeatedly by flowing water.
saltation
Fr = 1
critical flow
Fr > 1
supercritical flow
Fr < 1
subritical flow
it is used for 24-30% slope, contours cut into the hill slope in a step-like formation
bench terrace
it is used for 9-24% slope, for maximum soil and water conservation
zingg/ conservation bench terrace
stones are placed in a rectangular wire mesh, piled as blocks tied together, similar to check dams
gabions
a method of irrigation in which parallel strips are used where the water flows down at a nearly uniform depth.
border irrigation
in this method, water is applied to the crop field using small parallel channels to favor water infiltration while advancing down the field.
furrow irrigation
darcy’s law states that the flow of water through a porous medium is proportional to the
medium’s hydraulic conductivity
darcy’s law states that the flow of water through a porous medium is inversely proportional to the
length of flow path
