Module 5 Flashcards
1
Q
What did the engineers in the past have utilized to deal with water problems?
A
rule-of-thumb solutions
2
Q
True or False. Only in recent times have these endeavors on water problems in engineering taken on a systematic body of laws and quantitative formulas.
A
True
3
Q
It is a specialty dealing with the use of water in support of modern living, including agricultural, industrial, domestic, recreational, and environmental needs.
A
Water resources
4
Q
Enumerate some of the scopes of water resources engineering.
A
- finding and preservation of above and underground water sources
- understanding the movement of water in nature
- engineering the transport of water
- managing the erosive effects of water wave and current on shorelines
5
Q
True or False. Understanding the circulation of water on earth and managing the sources of water in a region requires a pragmatic approach.
A
False
6
Q
The decision on the water supply for a city or a region requires the _____________________ and ____________________________.
A
knowledge of water sources and quality and quantity of each source
7
Q
It is at the core of water resources system engineering.
A
the application of system analysis in water resources management
8
Q
It is available in the atmosphere, the oceans, on land, and with the soil and fractured rock of the earth’s crust.
A
Water
9
Q
Water molecules from one location to another are driven by the _____________.
A
solar energy
10
Q
How does moisture circulate from the earth?
A
into the atmosphere through evaporation, and then back into the earth as precipitation
11
Q
True or False. In hydrologic cycle, water is conserved - that is, it is neither created nor destroyed.
A
True
12
Q
In this cycle, water is conserved- that is, it is neither created nor destroyed.
A
Hydrologic Cycle
13
Q
Four key components of the hydrologic cycle.
A
- Precipitation
- Runoff
- Storage
- Evapotranspiration
14
Q
It occurs when atmospheric moisture becomes too great to remain suspended in clouds.
A
Precipitation
15
Q
Enumerate some of the forms of water that reach the earth from the atmosphere.
A
- rainfall
- snowfall
- hail
- frost
- dew
16
Q
Once the water reaches the earth’s surface, precipitation can become?
A
surface water runoff, surface water storage, glacial ice, water for plants, groundwater, or may evaporate and return immediately to the atmosphere
17
Q
It is the greatest source (about 90%) of precipitation.
A
Ocean evaporation
18
Q
About how much percent of the precipitation comes from ocean evaporation?
A
90%
19
Q
It is the predominant form of precipitation and its distribution over the world and within a country.
A
Rainfall
20
Q
It is the water that flows across the land surface after a storm event.
A
Runoff
21
Q
True or False. As rain falls over land, all of it gets infiltrated into the surface as overland flow.
A
False
22
Q
They combine to form channels as the flow bears down.
A
rills and gullies
23
Q
Channels combine further to form ________ and __________.
A
streams and rivers
24
Q
What do you call the geographical area which contributes to the flow of a river?
A
river or watershed
25
It is a portion of the precipitation falling on the land surface that does not flow out as runoff gets stored either as surface water bodies or sub-surface water bodies.
storage
26
These are surface water bodies like lakes, reservoirs, and wetlands or sub-surface water bodies.
Groundwater
27
It is the water infiltrating through the soil cover of a land surface and traveling further to reach the huge body of water underground.
Groundwater storage
28
True or False. The amount of groundwater storage is much lesser than that of lakes and rivers.
False
29
True or False. It is possible to extract the entire groundwater by practicable means.
False
30
True or False. Groundwater is in a state of continuous movement - flowing from regions of higher potential to lower.
True
31
Groundwater is in a state of ____________ - flowing from regions of higher potential to lower.
continuous movement
32
True or False. The rate of movement of groundwater is exceptionally small compared to the surface water movement.
True
33
It is a naturally occurring inland body of water.
Lakes
34
It is an artificial or natural inland body of water used to store water to meet various demands.
Reservoirs
35
It is natural or artificial areas of shallow water or saturated soils that contain or could support water-loving plants.
Wet Lands
36
It is the combination of evaporation and transpiration.
Evapotranspiration
37
It is the process of liquid converting into vapor, through wind action and solar radiation and returning to the atmosphere.
Evaporation
38
It is the cause of loss of water from open bodies of water, such as lakes, rivers, oceans, and the land surface.
Evaporation
39
True or False. Living near an ocean means more rainfall.
False
40
It is the process by which water molecules leave the body of a living plant and escape to the atmosphere.
Transpiration
41
The water is drawn up by the __________ and part of that is lost through the tissues of plant leaf called ________.
plant root system and stomata
42
True or False. In areas of abundant rainfall, transpiration is fairly constant with variations occurring primarily in the length of each plant's growing season.
True
43
True or False. Transpiration in dry areas varies greatly with the root area.
False
44
It includes all evaporation from water and land surfaces, as well as transpiration from plants.
Evapotranspiration
45
True or False. Some of the water that precipitates, flows on the ground surface or seeps through the soil first, then flows vertically and some continue to percolate deeper into the soil. This body of water will eventually reach a saturated zone and replenish or recharge the groundwater supply.
False
46
This is the recuperation of groundwater which is done to increase the groundwater table elevation.
Groundwater recharge
47
Give some artificial techniques for groundwater recharging.
1. constructing a detention dam called a water spreading dam or a dike
2. method of rainwater harvesting in a small scale
48
It is a detention dam used to store the flood waters and allow for subsequent seepage of water into the soil, so as to increase the groundwater table.
water spreading dam or dike
49
True or False. Due to its multiple benefits and the problems created by its excesses, shortages, and quality deterioration, water as a resource require special attention.
True
50
___________________, though a necessity, is now pertinent to be made sustainable.
Development of water resources
51
It implies that the development meets the needs of the present life, without compromising on the ability of the future generation to meet their own needs.
Sustainable development
52
It would ensure minimum adverse impacts on the quality of air, water, and terrestrial environment.
Sustainable development
53
They design artificial waterways, such as canals, channels, and aqueducts as well as manage water movement by designing and constructing dams, levees, canal locks, and other water-regulating devices.
Hydraulic engineering
54
For many regions, what is the major task of hydraulic engineers?
1. flood prevention and control
2. assessment of potential rainfall quantity
3. prediction of water levels along natural rivers, streams, or channels
4. form strategies to mitigate flooding hazards by improving the natural topography
55
It is fundamental to hydraulic-power generation.
Hydraulic engineering
56
What is a prerequisite in hydraulic power generation?
water-level differential (water head)
57
What provides the energy potential for power generation?
the difference in the water levels when water moves from a high level to a lower level
58
They are constructed mainly for power generation and have the potential to be used for flood control.
Dams
59
The stored water in a dam's reservoir can be used for:
1. agricultural
2. industrial
3. domestic consumption
4. recreational sports
60
It is a term that describes both gases and liquids.
Fluid
61
These forms are distinguished by the bonds between adjacent molecules (or atoms) that compose them/
Fluid
62
True or False. Molecules that make up a solid are relatively close together and are held in place by electrostatic bonds between the molecules.
True
63
Molecules that make up a solid are relatively close together and are held in place by ____________ between the molecules.
electrostatic bonds
64
True or False. Solids tend to keep their shape, even when acted on by an external force.
True
65
True or False. The forces holding fluid molecules together are much greater than those of solids, allowing fluids to deform easily under external forces.
False
66
True or False. Fluids can support shear forces.
False
67
True or False. Fluid will flow under the influence of the slightest stress.
True
68
Its molecules are so far apart that the bonds are too weak to keep them in place.
Gas
69
True or False. Gas is very compressible and always takes the shape of its container.
True
70
If the container of gas is removed, the molecules would _____________.
expand indefinitely
71
Its molecules are bonded with enough strength to prevent indefinite expansion but without enough strength to be held in place.
Liquid
72
Besides gas, they conform to the shape of their container.
Liquid
73
They tend to be incompressible.
Liquid
74
True or False. All liquids have surface tension, which is manifested differently in different liquids.
True
75
It results from a different molecular bonding condition at the free surface compared to the bonds within the liquid.
Surface tension
76
Surface tension results in properties called _________ and __________.
cohesion and adhesion
77
It enables water to resist a slight tensile stress.
Cohesion
78
It enables water to adhere to another body.
Adhesion
79
It causes the water in the test tube to wet the side for a short distance above the surface.
Adhesion
80
It shows a meniscus at the top of a test tube caused by surface tension.
Cohesion
81
It is the property of liquids that results from surface tension in which the liquid rises up or is depressed down a thin tube.
Capillarity
82
The liquid will wet the surface of the tube and rise up if?
adhesion predominates over cohesion
83
The liquid does not wet the tube and is depressed down if?
cohesion predominates over adhesion
84
True or False. Any material has a specific weight.
True
85
How is the specific weight of materials defined?
weight per unit volume
86
Density is defined as __________.
mass per unit volume
87
True or False. Both density and specific weight generally vary with the temperature of a material.
True
88
True or False. Thermal expansion results in greater mass in a given volume.
False
89
It is the ratio of its specific weight to that of pure water at a standard temperature and should not be confused with the ter specific weight.
specific gravity
90
True or False. Specific gravity is dimensionless.
True
91
What is the specific gravity of water under normal conditions encountered in stormwater management?
approximately 1.0
92
It refers to the study of water at rest.
hydrostatics
93
True or False. Water in a container exerts pressure at a acute angle, or normal, to the container walls or on any submerged surface.
False
94
True or False. As a consequence of the absence of shear force in water, the pressure at any point in water at rest is equal in all directions.
True
95
It is a simple tube connected to a body of water with its other end open to the atmosphere.
piezometer
96
True or False. Water enters the piezometer and rises until it reaches a height proportional to the pressure.
True
97
It is used to measure water pressure in a pipe.
manometer
98
When the water pressure to be measured is relatively high, a piezometer may be inadequate, and a _________ must be used.
manometer
99
True or False. High pressure would require a short piezometer tube, but a manometer solves this problem by use of a heavy liquid such as mercury.
False
100
True or False. High pressure would require a short piezometer tube, but a manometer solves this problem by use of a heavy liquid such as mercury.
False
101
It is the uplifting force exerted by water on a submerged solid object.
Buoyancy
102
It refers to the study of water in motion.
hydrodynamics
103
Another term for hydrodynamics.
hydrokinetics
104
True or False. Water can move in all directions but cannot be channeled into a prevailing direction such as flow in a pipe.
True
105
True or False. When water flows in a conduit or pipe, all the particles tend to travel separately.
False
106
True or False. All particles of water flowing in a conduit travel generally in the same direction and generally at the same speed.
True
107
What are the two fundamental parameters used to describe the motion of water confined to a conduit.
velocity and discharge (rate of flow)
108
It describes the rate of change in the position of the water particles as defined in fundamental mechanics.
Velocity
109
Since all the particles flowing in a conduit move at slightly different speeds, what is the velocity of the flow?
the average speed of all the particles
110
It is defined as the average velocity of all water particles crossing an imaginary plane perpendicular to the direction of motion at a particular location along the conduit.
Velocity of flow
111
How is the parameter v expressed?
feet per second or meters per second
112
It describes the amount of water passing through an imaginary plane per unit of time at a particular location along the conduit.
Discharge or rate of flow, Q
113
How is the parameter Q measured and expressed?
measured as volume per unit of time and expressed as cubic feet per second or cubic meters per second
114
Enumerate the most basic classification of the flow of water.
1. Laminar flow versus turbulent flow
2. Steady flow versus unsteady flow
3. Uniform flow versus nonuniform flow
115
It describes the smooth flow of water with relatively low velocity.
Laminar Flow
116
As the water flows in a conduit, it moves in parallel layers with no cross currents. What do you call this type of flow?
Laminar flow
117
As velocity increases, the flow becomes rougher with pulsating crosscurrents within the conduit. What do you call this type of flow?
turbulent flow
118
What is another difference between laminar and turbulent flow besides smoothness?
energy loss
119
True or False. In laminar flow, the energy loss is much greater than in turbulent flow.
False
120
It occurs when discharge is unchanged over time.
Steady flow
121
It results from a relatively rapid change of discharge, such as the opening of a gate or closing of a valve.
Unsteady flow
122
What kind of flow is the following? Emptying of a tank, where the discharge from the tank is a function of the remaining depth.
Unsteady flow
123
It occurs when the cross-sectional area of the conduit remains constant.
Uniform flow
124
This type of flow is easily illustrated by flow in pipes or uniformly shaped channels.
Uniform flow
125
What type of flow is the following? A change in pipe size or flow from a reservoir into a channel.
Nonuniform flow
126
True or False. In solving hydraulic problems, concepts of energy are used intensively.
False
127
What is the unique problem when referring to the energy of water?
The fluid nature of water does not allow a given quantity to remain conveniently in place when it moves.
128
It is used to describe the energy of water in solving hydraulic problems.
Energy head
129
It refers to water energy per unit weight of the water and uses units of length, such as feet or meters.
Head
130
It is used to describe mechanical energy, that is, potential and kinetic, as well as energy loss, such as friction and turbulence.`
Head
131
It is described as a potential energy head and has length units.
potential energy
132
It is described as a kinetic energy head, called a velocity head, and also has units of length.
kinetic energy
133
True or False. Head is truly energy and is energy per unit weight.
False
134
It describes the potential energy per unit weight of a mass of water due to the height of the water above some datum.
Position Head
135
It describes the potential energy per unit weight of a mass of water due to the pressure exerted from above.
Pressure Head
136
It describes the kinetic energy per unit weight of a mass of water due to kinetic energy resulting from its motion.
Velocity Head
137
It describes the loss of energy per unit weight of a mass of water due to friction and turbulence.
Head Loss
138
These are structures that use hydraulic principles to control the flow of water.
Hydraulic devices
139
It is a hole in the wall of a container through which water may flow.
Orifice
140
Flow lines are parallel and closest together at section a-a. This point is referred to as the ____________.
vena contracta
141
It is a structure that, like an orifice, regulates the flow of water out of an impoundment or reservoir
Weir
142
A weir consists of a _______________ over which water is allowed to flow.
horizontal surface
143
What are the typical uses for weir?
1. outlets structures for dams and detention basins, as well as other impoundments such as holding tanks in sewage treatment plants
144
They are widely used as measuring devices with such applications as natural streams and treatment works
Weirs
145
Enumerate the classification of weirs by their cross-section shape
1. sharp-crested weir
2. broad-crested weir
3. ogee weir
146
Enumerate the classification of weirs by their front view shape.
1. rectangular weir
2. triangular or v-notch weir
3. cipoletti weir
147
In weirs, the energy that pushes water over the crest is measured by the ______ above the crest.
head H
148
When water flows downhill in any conduit with the water surface exposed to the atmosphere (free surface) it is said to undergo ___________.
open channel flow
149
It is the study of the mechanics of water flowing in open conduits, which generally include channels, streams, and even pipes (not flowing under pressure).
Open channel hydraulics
150
True or False. Channels constructed for the conveyance of water can have many different cross-sectional shapes as well as different slopes and alignments.
True
151
What do you call a channel when it changes shape, slope, or alignment, and the flow characteristics are correspondingly affected?
nonprismatic
152
Give some of the typical cross-section shapes.
1. rectangular
2. trapezoidal
3. triangular
4. parabolic
5. irregular variation
153
Channels are also constructed of many different materials, ranging from __________ to ________ to _________.
grass-lined soil, stone, and concrete
154
It is the material used to form a channel.
lining of the channel
155
True or False. The type of material affects friction because it increases or decreases velocity at the interface between the water and the channel lining.
False
156
It is defined as a great flow of water, especially a body of water, rising, swelling, and over-flowing land not usually thus covered; a deluge; a freshet; an inundation.
flood
157
It is considered to be a phenomenon associated with an unusually high stage or flow over land or coastal area, which results in severe detrimental effects.
Flood
158
It implies all measures taken to reduce the detrimental effects of the flood.
Flood Control
159
Enumerate the several types of flooding.
1. River flooding
2. Flash floods
3. Urban flooding
4. Storm surge or Tidal flooding
5. Floods arising due to failure of dam
160
This is the major cause of flooding extensive areas as a result of heavy rains in the catchment areas as well as local areas thereby increasing the river levels.
River flooding
161
This result is due to heavy rains in hilly areas which cause local rivers and small streams to rise to dangerous level within a short period of time say 6 to 12 hours.
Flash floods
162
These are caused by heavy and continuous rains.
Flash floods
163
Local heavy rains up to 100 mm or more in a day over the city and larger towns can cause damaging and disruptive flooding due to poor or chocked drainage and rapid runoff.
Urban Flooding
164
This result is mostly due to tropical disturbances, developing into cyclones and crossing surrounding coastlines. Cyclone-induced storm surges have devastating consequences in coastal areas and such surge-induced floods may extend kilometers inland.
Storm surge or Tidal flooding
165
A large number of large and small dams are constructed to store water for various purposes. Due to poor maintenance and due to exceptionally high precipitation a severe flood may result causing the failure of the dam. This causes a surging waterfront traveling with high velocity causing the destruction of properties and loss of life.
floods arising due to failure of the dam
166
Flood management measures can be classified as?
1. short-term measures
2. long-term measures
167
It determines the measures to be taken up during floods.
1. nature and extent of flood damages
2. local conditions
168
True or False. Long-term measures are dependent on the effectiveness of short-term measures.
False
169
These measures are adopted for giving quick results when immediate relief to some pockets or locations is felt necessary.
Short-term measures
170
Enumerate the short-term measures.
1. Constructions of embankments along the low-level banks that are subject to frequent flood spells.
2. Construction of raised platforms for temporary shelter during floods.
3. Dewatering by pumps of flooded pockets, towns when gravity discharge of floodwater is not possible.
4. Construction of floodwalls near congested areas of cities, towns, and industrial belts.
171
Enumerate the long-term measures.
1. Construction of storage reservoirs to moderate the flow peak thereby ensuring regulation of flood downstream.
2. Integrated watershed management in the hilly area catchment, which ensures reduction in surface runoff, erosion, and increase of infiltration capacity thereby reducing the impact of floods.
3. Flood forecasts and warnings based on hydro-geomorphological studies which can be given with some lead period, thereby ensuring minimization of property loss and loss of human life by shifting them to safer places.
172
To reduce losses due to flood the strategies to be followed can be stated as:
1. Modify flooding by structural means
2. Flood Forecasting (This is a non-structural measure)
3. Modify susceptibility to flood damage
173
Herein the strategies to be followed involve the construction of dams, dikes, levees, channel alterations, high-flow diversions, and land treatment.
Modify flooding by structural means.
174
The main idea of this strategy is to keep water away from the potential damaged areas.
Modify flooding by structural means.
175
Here, a forecast of flooding is provided at the potential damage points. The population both human, as well as livestock and movable properties, are shifted to a safer if there is a chance of flood damage.
Flood forecasting (This is a non-structural measure)
176
In this strategy, the objective is to keep people away from inundated areas.
Flood forecasting (This is a non-structural measure)
177
In this strategy, regulations are frames to avoid the desirable or unwise rise of flood plains. Necessary steps are taken to modify the impact of flooding through individual or group action designed for assisting people in the preparatory, survival, and recovery phase of floods which are namely through education and information on floods, insurance, taxation relief, etc.
Modify susceptibility to flood damage
178
They are invariably provided in storage dams for the safe disposal of the excess water flowing into the reservoir after it has filled up.
Spillways
179
They may have simple overflow crests or may have controlled crests with gates.
Spillways
180
They permit the controlled release of surplus water in excess of the reservoir capacity and convey the same into the river channel below the dam or to any other drainage area in such a manner that the foundations are protected from erosion and scour.
controlled crest in spillways
181
True or False. Overflow on the dam can be allowed unless the downstream face is designed for passing the floods with requisite depth and the bed is well protected to take the impact of falling waters.
False
182
True or False. Many failures of dams have been attributed to adequate spillways capacity with consequent overtopping of the bund.
False
183
True or False. In the case of earthen dams if the water overtops there is no possibility of saving the dam from failure.
True
184
It is a very important factor in the design of earthen dams.
Adequate spillway
185
True or False. The objective of the spillway design should be to provide a safe and adequate spillway structure at most economical cost, impairing the safety of the dam.
False
186
True or False. Dam failure due to inadequate spillway capacity may result in heavy loss of life and property.
True
187
In the hydraulic design of a spillway, the following procedure is generally followed:
1. First, hydrological analysis to determine the magnitude of the design flood.
2. And thereafter detailed hydraulic analysis
188
Spillways may be classified as ____________ and ___________.
controlled crest spillways and uncontrolled crest spillways
189
The operations on these spillways are controlled by the operation of the gates.
controlled crest spillways
190
They come into action immediately after the water level reaches the crest of the spillway.
uncontrolled or automatic spillway
191
Give some typical examples of uncontrolled or automatic spillways.
1. ordinary simple weirs provided on small dams or the overflow dams
2. siphon spillways
3. shaft spillways
192
True or False. By having a controlled crest for the spillway, the flood lift can be reduced.
True
193
The gates can be lifted at the onset of floods so that the reservoir is ___________________________.
kept low and the flood passed on
194
True or False. As the flood subsides the gates can be lowered and the storage affected.
Eurt
195
Nearly all spillways fall into one of six types or are made of combinations of these types. These are:
1. overfall (free or gated)
2. side channel
3. chute or trough
4. shaft or morning glory
5. siphon
6. emergency
196
True or False. The overall type is the most common and is adopted in masonry dams having sufficient crest length to provide the requisite capacity.
Eurt
197
It will act as orifices under partial control of gates and as open crest weirs when full gate openings are made.
Overfall spillways with crest gates
198
These are commonly adapted for earth dams.
Chute spillways
199
They are most suitable in narrow canyons.
side channels and shaft spillways
200
They are usually used to provide approximately constant headwater flow under varying flow.
siphon spillways
201
It is an auxiliary spillway provided to take care of the possibility of having a flood greater than the spillway design flood.
Emergency spillway
202
It involves artificially providing crops with water.
Irrigation
203
This technique is used in farming to enable plants to grow when there is not enough rain, particularly in arid areas.
Irrigation
204
It is also used in less arid regions plants with the water they need when seed setting/
Irrigation
205
About __% of the world's water catchment is used in farming, which continues to make increasing use of irrigation.
66
206
But in most irrigation systems, ___________ % of the water used does not benefit the plants.
50 to 60
207
True or False. It is necessary to set up a more carefully designed irrigation schemes that ensure minimal agricultural production while preserving the resource.
False
208
True or False. The scope of irrigation is limited to the application of water to the soil.
False
209
It deals with all aspects and problems extending from the watershed to the agricultural farms.
Irrigation
210
It deals with the design and construction of all works, such as dams, weirs, head regulators, etc.
Irrigation
211
They are required to have knowledge of the cultivation of various crops; their maturing and protection from pests.
irrigation engineer
212
An irrigation engineer is also required to have the knowledge of _____________ and _______________.
1. cultivation of various crops
2. maturing and protection from pests
213
The scope of irrigation can be divided into two heads:
1. Engineering aspect
2. Agricultural aspect
214
Irrigation's basic functions in its engineering aspect are:
1. Storage, Diversion, or Lifting of Water
2. Conveyance of Water to the Agricultural Fields
3. Application of Water to Agricultural Fields
4. Drainage and Relieving Water-Logging
5. Development of Water Power
215
This is the first phase of irrigation engineering.
Storage, Diversion, or Lifting of Water
216
Through the construction of a dam across the river, a suitable reservoir can be created and water can be stored. What basic function is this?
Storage, Diversion, or Lifting of Water
217
True or False. If a river is perennial and carries sufficient discharge, suitable diversion works, such as a weir, barrage, and bandana, can be constructed across the river and water can be diverted to the canal.
True
218
True or False. Places where the ground water table is high, suitable wells can be dug and water can be lifted and fed to small channels or pipes.
Eurt
219
The stored or diverted water is conveyed to the agricultural fields through some suitable distribution system. What basic function is this?
Conveyance of Water to the Agricultural Fields
220
True or False. If the project is big, the distribution system will consist of two or more main canals and a number of distributaries, and minors.
Eurt
221
In irrigation, from the canal, the water is led to the field through _________ or __________.
water course or field channel
222
This second phase includes the design and construction of a suitable canal system, along with various regulatory works such as head regulators, cross regulators, falls, etc. for the efficient working of the canal.
Conveyance of Water to the Agricultural Fields
223
______________, such as aqueducts, super passages, level crossings, bridges, etc. will have to be designed and constructed at the places where the canal crosses a natural drain or a road.
Suitable cross drainage
224
The water is applied to the crop y flooding. Furrows, corrugations, subsoil irrigation, or by sprinkling.
Application of Water to Agricultural Fields
225
Proper disposition of excess water by suitable drainage methods is very important. What function is this?
Drainage and Relieving Water-Logging
226
True or False. The design of surface and sub-surface drainage systems is of vital importance in maintaining the high productivity or irrigated lands.
True
227
Most irrigation projects are associated with the generation of hydroelectric power either at the dam site or at canal falls.
Development of Water Power
228
Most irrigation projects are associated with the generation of _________________ either at the dam site or at canal falls.
hydroelectric power
229
Enumerate the benefits of irrigation.
1. Increase in crop yield
2. Protection from famine
3. Cultivation of superior crops
4. Elimination of mixed cropping
5. Economic development
6. Hydropower generation
7. Domestic and Industrial water supply
230
The production of almost all types of crops can be increased by providing the right amount of water at the right time, depending on its shape of growth. Such a controlled supply of water is possible only through irrigation.
Increase in crop yield
231
The availability of irrigation facilities in any region ensures protection against the failure of crops or famine due to drought. In regions without irrigation, farmers have to depend only on rain for growing crops, and since the rains may not provide enough rainfall required for crop growing every year, the farmers are always faced with risk.
Protection from famine
232
With the assured supply of water for irrigation, farmers may think of cultivating a superior variety of crops or even other crops which yield a high returns. Production of these crops in rainfed areas is not possible because even with the slight unavailability of timely water, these crops would die and all the money invested would be wasted.
Cultivation of superior crops
233
In rainfed areas, farmers have a tendency to cultivate more than one type of crop in the same field such that even if one dies without the required amount of water, at least he would get the yield of the other. However, this reduces the overall production of the field. With assured water by irrigation, the farmer would go for only a single variety of crop in one field at any time, which would increase the yield.
Elimination of mixed cropping
234
With assured irrigation, the farmers get higher returns by way of crop production throughout the year, and the government, in turn, benefits from the tax collected from the farmers in the base of the irrigation facilities extended.
Economic development
235
Usually, in the canal system of irrigation, there are drops or differences in the elevation of the canal bed level at certain places. Although the drop may not be very high, this difference in elevation can be used successfully to generate electricity. Such small hydroelectric generation projects, using bulb-turbines have been established in many canals, like Ganga canal, Sarada canal, Yamuna canal, etc.
Hydro power generation
236
Some water from the irrigation canals may be utilized for domestic and industrial water supply for nearby areas. Compared to the irrigation water need, the water requirement for domestic and industrial uses is rather small and does not affect the total flow much.
Domestic and Industrial Water supply
237
True or False. A plot of land growing a certain crop or a combination of crops has to be supplied with water from time to time.
Eurt
238
True or False. The plot or field is expected to receive water from rain falling on the land surface.
True
239
True or False. All of the rain as in a light shower reach the ground as it may not be intercepted by the leaves of the plant during a heavy downpour; all of the water might flow aways as surface runoff.
False.
240
True or False. Only a certain amount of falling rain may be effective in raising the soil moisture that is actually useful for plant growth.
True
241
True or False. For proper crop growth, the effective rain has to be supplemented by artificially applying water to the field by irrigation.
True
242
If the area of the field is small, water may be supplied from the __________________.
local ground water source
243
If the field is large supplemented irrigation water may be obtained from a ______________.
local surface water source
244
What is the work of a water resources engineer?
to design a suitable source for irrigation after knowing the demand of water from field data
245
It is the total water required for crop growth over its entire life span.
crop period
246
It is the watering stops same time before harvest and the time duration from the first irrigation during sowing up to the last before harvest.
base period
247
It is when the soil is moistened with water to help in sowing the crops.
paleo irrigation
248
It is used to describe the watering given to a crop when the plants are still young.
kor
249
It is the total depth of water required to raise a crop over a unit area of land.
delta
250
It is usually the maximum single watering required, and other watering are done at usual intervals.
kor
