5th six months Flashcards
1
Q
T or F
Safety is not the operators responsibility of the supervisor.
A
False
2
Q
T or F
Plant visitors impressed by records showing efficient operation, and their opinions are seldom influenced by the appearance of the plant grounds.
A
False
3
Q
T or F
After finishing this program, you will not have to study water treatment anymore.
A
False
4
Q
T or F
In many water treatment plants the operator must be a jack-of-all-trades”
A
True
5
Q
T or F
Excessive hardness is removed from waters to prevent the staining of clothes and plumbing fixtures.
A
False
6
Q
The purpose of a water treatment plant is to produce water free of:
A
Disagreeable tastes Disease causing organisms Toxic substances Undesirable odors Unpleasant appearances
7
Q
The MAIN purpose of flocculation is to:
A
Gather together particles to form larger particles
8
Q
Screens are installed in intake structures to remove ___ from the raw water
A
Debris & leaves
9
Q
Water treatment plant operators are responsible for:
A
Explaining purpose of water treatment plant
Keeping accurate records
Maintaining appearance of their plant
Protecting the health and well being of the community
Safety performing their job
10
Q
An experienced water treatment plant operator may be expected to:
A
Develop a safety program Maintain equipment Operate treatment processes Respond to complaints Train new operators.
11
Q
Drinking water treatment plant operators have the responsibility of producing:
A
Pleasant drinking water, safe drinking water.
12
Q
The MAIN purpose of prechlorination are to:
A
Help control taste- and odor-causing substances. kill most disease-causing organisms.
13
Q
Typical duties performed by a water treatment plant operator include:
A
Collect representative water samples Conduct safety inspections Load and unload chemicals Order repair parts & tools Start and stop plant equipment.
14
Q
Water treatment plant operators must be able to explain the purpose & operation of their plant to:
A
City council members, civic organizations, officials of regulatory agencies, representative of news media, school children.
15
Q
T or F
The energy crisis and water shortages are linked together,
A
True
16
Q
T or F
Both animal life and plant life depend on water for survival.
A
True
17
Q
T or F
Large cities may obtain their raw water supply from a stream or river into which the treated wastewater from an upstream city has been discharged.
A
True
18
Q
T or F
Laboratories can easily detect in water samples most of the new chemicals that are developed each ear.
A
False
19
Q
T or F
Acid rain is formed by the evaporation of acid waters from mine drainage.
A
False
20
Q
T or F
Precipitation is high in bacterial count.
A
False
21
Q
T or F
Color in water is objectionable mainly from the standpoint of health.
A
False
22
Q
T or F
Clear water is usually safe to drink.
A
False
23
Q
T or F
Running water usually purifies itself to drinking water within a reasonable distance.
A
False
24
Q
Sources of contamination of water supplies include:
A
Acid rain Industrial waste changes Intrusion of sea water into groundwater basins Mineral residues from irrigation Salt from de-icing highways
25
Sources of groundwater contamination include:
Agricultural drainage
seawater intrusion
Seepage from septic tank leaching systems
Seepage from improper disposal of hazardous wastes
Surface runoff into wells.
26
The basic types of water rights are called:
Appropriative
Prescriptive
Riparian
27
For purpose of discussion, surface water supplies may be divided into which of the following classes?
Lakes, reservoirs, rivers
28
Diseases that may be spread through a water supply include:
Dysentery, giardiasis, typhoid fever
29
Typical uses of reclaimed water include:
Crop irrigation
Industrial reuse
Landscape impoundments
Landscape irrigation
30
When conducting a sanitary survey, which of the following items would pertain to a water supply in a lake?
```
Adequacy of supply as to quantity
Algae growth potential
Normal period of detention
Protective measures in connection with watershed
Wind direction
```
31
Items requiring protective measures in watersheds that serve as the source of water supply include control of?
```
Disposal of brines
Fishing
Ice cutting
Sanitary landfills
Swimming
```
32
Which types of substances may alter the quality of water as it moves over or below the surface of the earth?
Biological
Chemical
Physical
Radiological
33
Turbidity in water results from the presence of:
Finely divided organic material
Plankton
Suspended material
34
Most individuals find that water having a temperature of ___ is most palatable.
50 degrees to 60 degrees F
35
The process by which water vapor is released to the atmosphere by living plants is called:
Transpiration
36
Water quality characteristics of surface water supplies include:
Suspended solids
| Turbidity
37
Lakes and reservoirs are susceptible to algal blooms when:
Sufficient nutrients are available
| Temperature is right
38
Sources of odors in drinking water include:
Growths of algae
| Hydrogen sulfide
39
A public water system according to the Safe Drinking Water Act (SDWA) includes all public or privately owned systems that:
Have at least 15 service connections which are used at least 60 days out of the year, serve an average of at least 25 people at least 60 days out of the year.
40
The basic objectives in the operation of a water treatment plant include:
Production of a safe drinking water
Production of an aesthetically pleasing drinking water
Production of drinking water at a reasonable cost
41
Before the intake for a water supply is located in a river or stream, a careful study must be made of the:
Degree of stream scour
Settling out of silt
Stream bottom
42
The amber color in water could indicate the presence of:
Acid waters from mine drainage
| Humic substances
43
Determine the chlorinator setting in lbs/day if:
| Chlorinator feed rate// lbs/day= (2 MGD)(3 md/L)(8.34 lbs/gal)
50 lbs/day
44
Estimate the chlorine dose to a drinking water in mg/L if chlorine dose, mg/L= 14lbs/day // (.9333MGD)(8.34 lbs/gal)
1.8 mg/L
45
T or F
| Local conditions have little influence on methods of managing lakes and reservoirs used for domestic water supplies.
False
46
T or F
| The amount and type of public use allowed on reservoirs has been standardized by laws and regulations.
Falsa
47
T or F
Few of the conditions which adversely affect water quality in domestic water supply reservoirs result from the impacts of man's activities upon the environment.
False
48
T or F
| Objectionable tastes and odors in domestic water supplies are often related to the occurrence of algal blooms.
True
49
T or F
Many conventional water treatment plants are capable of reducing tastes and odors to acceptable levels when operated properly.
True
50
T or F
| Algae can die of oxygen starvation
True
51
T or F
| In a monomictic lake during winter months, the lake temperature is uniform from top to bottom.
True
52
T or F
| Mixing occurs between the epilimnion and hypolimnion zones in thermally stratified lakes.
False
53
T or F
| Fish kills can result from algae clogging the gills of fish.
True
54
T or F
Once vegetation removal is accomplished at a reservoir site, regrowth should be controlled until the reservoir is filled.
True
55
T or F
| Chlorination of a water supply may either be used for managing watersheds in most cases is the regulatory process.
True
56
T or F
Phosphate- base fertilizers usually do not cause water quality problems caused by nitrogen fertilizers because of the soil- binding characteristics of Phosphate compounds.
True
57
T or F
| All algae react the same way to copper sulfate.
False
58
T or F
| Destratification always increases the of algal blooms in reservoirs.
False
59
T or F
| With complete destratification, temperatures in a reservoir will be nearly uniform from top to bottom.
True
60
T or F
Through proper design and operation, reservoir destratification systems can be used to manipulate temperatures and dissolved oxygen content to desired levels.
True
61
T or F
| The operator of a small water supply system must be able to manage the watershed as well as operators of large systems.
True
62
T or F
| Records are very valuable only when they are completed and filed by lab personnel.
False
63
T or F
| The inlet to a single level intake is usually located near the water surface.
False
64
Nutrients act as a(n) ___ in a lake.
Fertilizer
65
Reservoirs which are rich in nutrients and very productive in terms of aquatic animal and plant life cure are commonly referred to as:
Eutrophic
66
What problems may be created for operators by algal blooms in domestic water supply reservoirs?
```
Dissolved oxygen depletion
increased pH which reduce chlorination efficiency
Increased organic loadings
Shortened filter runs
Tastes and odors
```
67
What water quality problems are caused by iron and manganese in drinking water?
Dirty water
Staining clothes
Staining porcelain fixtures
68
Proper management can increase recreational values of a reservoir by:
Controlling mans activities on the watershed
Reducing large mats of algae
Reducing scums of algae
Reducing vegetation before flooding
69
Trees and brush should be removed from areas to be flooded by reservoirs to reduce the ___ loadings.
Nutrient
| Organic
70
Anaerobic conditions in the hypolimnion of a reservoir can cause:
Fish kills
Iron and manganese problems
Rotten egg odors
71
Algal blooms in lakes and reservoirs can be controlled by:
Chemical methods
Limiting nutrient recycling
Preventing nutrient inflow
72
Which of the following water quality indicators have a significant impact on the efficiency of copper sulfate as an algaecide?
Alkalinity
pH
Suspended matter
Water temperature
73
Which chemical is used to make copper sulfate effective in highly alkaline waters (greater than 150mg/L alkalinity)?
Citric acid
74
The reasons for using destratification programs in domestic water supply reservoirs include improving:
Aesthetics
Fisheries
Recreational values
Water quality
75
Important water quality indicators that should be considered in a lake destratification program include:
Dissolved oxygen
| Temperature
76
Factors affecting watershed management programs include:
Size of watershed
Topography
Vegetative conditions
Water quality problems
77
Which of the following watershed practices can affect water quality in a water supply reservoir?
```
Control of land use
Livestock grazing
Oil and gas exploration and drilling
Septic tank leaching systems
Soil conservation programs
```
78
Water quality laboratory analyses which may be best performed by commercial laboratories include"
Pesticides
Radioactivity
Trihalomethanes
79
Intake facilities should prevent ___ from entering a water supply system.
Algal scums
| Fish
80
Water quality problems caused by anaerobic water entering the intake -inlet including high concentrations of:
Hydrogen sulfide
Iron
Manganese
81
Types of intake screens include:
Slotted plates
Woven wine
Vee wire
82
Methods of cleaning intake screens include:
Brushing with bristle brushes
Jetting with high pressure water
Reversing the flow
83
Factors that can adversely affect water quality in lakes and reservoirs include:
```
Agricultural runoff
Drainage from mining areas
Logging operations
Grazing of livestock
Runoff from urban areas
```
84
Objectionable tastes and odors in a domestic water supply may be caused by:
Algae
Hydrogen sulfide
Overturns
85
Trihalomethanes are often formed during chlorination by reactions with:
Natural organic materials
86
Purposes of reservoir management programs include:
Improvement and maintenance of fishery
Improvement and maintenance of recreational
Improvement and maintenance of water quality
Reduction of water treatment costs
87
What is the surface area of a rectangular settling basin 60ft long and 15ft wide?
900sq ft
88
What is the surface area of a circular clarifier 40ft in diameter?
1256sq ft
89
Calculate the volume in cubic ft of a rectangular settling basin 8ft deep, 15ft wide, and 60 ft long?
7200 cu ft
90
Calculate the volume in cubic ft of a circular clarifier 7ft deep and 40 f in diameter?
8800 cu ft
91
How many lbs of copper sulfate will be needed to dose a reservoir with .5mg/L copper? The reservoir volume is 20 million gallons. The copper sulfate is 25% copper.
335 lbs
92
Thermal limits are the direct result of?
The thermal capability of system equipment
93
T or F
| Reactive power flow is influenced more by system power and torque angles than reactive power
False
94
At what line power angle does the MW transfer across a transmission path equal 1/2 of the paths PMAX?
30 degrees
95
A transmission line is rated 1000 MVA. The power flow is currently 0MW and 1001 Mvar. Is the transmission line overloaded?
Yes
96
The TTC limit has been determined to be 1000MW from east to west for a particular transmission path. The transmission path operator sells 500 MW of the TTC. What is the paths ATC?
500MW
97
T or F
A distribution line is rated at 50MVA. The lines power flow is currently 50MW and -50MVAR. This distribution line is overloaded.
True
98
Angle stability limits are the result of?
High torque and power angles
99
If the resistance is ignored, the maximum theoretical MW flow across a transmission line will occur at a power angle of:
90 degrees
100
If the resistance is ignored, the maximum theoretical Mvar flow across a transmission line will occur at a power angle of:
180 degrees
101
200 MW is scheduled to flow from bus "X" to bus "Y". Transmission line "A-B" has a 10% distribution factor for this schedule. How much of the 200 MW schedule will flow on transmission line "A-B"?
20MW
102
T or F
| Complex power is the vectoral difference of active and reactive powers?
False
103
The Greek letter theta (θ) is used to represent what?
Phase angle
104
T or F
| A synchroscope is used to compare freq., voltage phase angle, and voltage magnitude.
True
105
T or F
| If two power paths are available, less power will flow on the path with the least impedance?
False
106
A phase shifting transformer (PST) primary function is to?
Adjust the flow of active power
107
T or F
| Three factors that affect power flow are path impedance, voltage magnitude, and current flow
False
108
T or F
| Dams are classified according to their use, their hydraulic design or the material of which they are constructed.
True
109
T or F
The purpose of detention dams are ordinarily constructed to retard flood runoff & increase the effects of sudden floods.
False
110
T or F
Earthfill dams are the most common dams used because they are principally constructed of the material from local natural material. Requiring minimum of processing.
True
111
What is the membrane of a rockfill dam made of?
All of the above; concrete slab, asphaultic concrete paving, steel plates.
112
T or F
Concrete arch dams are suitable for sites where the ratio of the width between abutments to the height is greater and where the foundation at the abutments is not solid rock capable of resisting arc thrust.
False
113
T or F
The single arch dam spans a canyon as one structure and is usually limited to maximum crest length to height ratio of 20:1.
False
114
T or F
A timber dam is not economical for modern construction because the amount of labor involved in a timber dam, coupled with short life of the structure make this type uneconomical.
True
115
What are some of the advantages of a rock foundation for a dam?
Both A & B; Free of significant geology defects, are resistant to erosion & percolation.
116
What type of design concerns should be considered if a silt or fine sand foundation is available?
```
Include non-uniform settlement
Prevention of piping
Excessive percolation losses
Uplift forces
Potential soil collapse upon saturation.
```
117
The investigation for a potential dam site primarily consists of three stages, or levels of study, what are they?
Appraisal, feasibility, design investigations.
118
T or F
| The primary criteria for rip rap is quality & size.
True
119
Why are stream deposits a good source of concrete aggregate?
All of the above; they are easy & inexpensive to excavate or process, streams naturally sort deposits, abrasion caused by stream transportation eliminates some of the weaker material.
120
T or F
It is important to have an effective reservoir geologic map because the map is essential for planning & conducting the investigations.
True
121
What do geologic maps identify?
Both A & B; surrounding areas, rock units.
122
T or F
Agricultural soil maps are useful for engineering purposes because they provide detailed soil data & information relating to drainage areas.
True
123
In construction of foundation & earthwork for dams, why are the physical properties of soil important?
Unit weight, permeability, shear strength
124
T or F
What happens if silt & clay have as little as 10% of the particles in sand & gravel & are smaller than the No. 200 sieve size they will become saturated,
False
125
T or F
In field classification, if the soil is gravel it can be identified as clean or dirty means that it has an appreciable amount of fines.
True
126
T or F
Streak means in reference to rocks that the color of the fine powder of a mineral, obtained by rubbing it on the unglazed portion of the porcelain tile is known as its streak.
True
127
What are the mechanisms that develop soil deposits on the surface of soil?
Water, ice and wind.
128
T or F
The definition of moderately hard rock is that it can't be scratched with a knife or sharp pick with light or moderate pressure.
False
129
What are the non-accessible exploration methods for subsurface materials?
All of the above; auger drilling, core drilling, rotary drilling.
130
T or F
| A vane shear test is an in place test to determine the undrained shear strength of a saturated cohesive soil.
True
131
T or F
The reason the earthfill dam is the most common type of dam because its construction involves using materials in their unnatural state with more processing.
False
132
T or F
The essential requirements of the foundation for an earthfill dam is that it provides stable support for the embankement under all conditions of saturation & loading, and that it provides sufficient resistance to seepage to prevent excessive loss of water.
True
133
T or F
| The purpose of grouting a dam foundation is to act as a binder and fills in the voids in the foundation.
True
134
T or F
| The purpose of toe drains is to give the operator an elevation reading.
False
135
What are some disadvantages of grout caps?
Excavation for the cap may disturb (damage) foundation.
136
T or F
The methods of treating silt & clay foundations are based on the soil type & location of water table and the density of the soil.
True
137
Why can't a designer of an earthfill dam rely on the application of mathematical analysis or formulas to determine the required cross section to the degree that one can for a concrete dam?
All of the above; soil occurs in infinite combinations of size graduation, composition and corresponding variations in behavior under different conditions of saturation & loading
138
T or F
In reference to dams, "freeboard" means the vertical distance between the crest of the embankment & the reservoir water surface.
True
139
Name some material used for upstream slope protection on earthfill dams.
```
Steel facing
Soil-cement pavement
Rock riprap
Precast concrete blocks
Concrete pavement
```
140
Rock for riprap should be hard, dense & durable. It should be able to resist long exposure to weather. What type should be used?
A & B, limestone & sandstones
141
What are the conditions that must occur before a rockfill dam can prove to be economical?
All of the above; Earthfill materials are difficult to obtain or require extensive processing before use, short construction seasons prevail, the dam is to be raised at a later date.
142
Does uplift pressures and erosion caused by seepage through a rockfill dam generally cause problems?
No, rockfill materials do not generally constitue significant design problems.
143
Name materials that are used as impervious material in rockfill dam.
Steel, wood, concrete, earth material.
144
T or F
Two advantages of using an internal membrane in a rockfill dam are shorter grout curtain lengths & less total area exposed to water.
True
145
T or F
| Bedrock foundations that are soft & erosion resistant are the most desirable for a rockfill dam.
False
146
T or F
Limited settlement is critical in the construction of rockfill dams because excessive settlement may rupture the upstream membrane or cause joint separation with subsequent water loss.
True
147
Name some advantages of asphaltic concrete.
```
All of the above;
Flexibility
Can tolerate larger settlement than reinforced concrete
Economical alternative to concrete
Dependable when correctly constructed
```
148
T or F
Outlet works are classified according to their purpose, their physical & structural arrangement, or their hydraulic operation.
True
149
T or F
The outlet works position in relation to the reservoir storage level is so important to attain the required elevation capacity.
False
150
What should control devices selection of outlet works arrangement be based upon?
Commercially available gates and valves or relatively simple gate design where possible.
151
T or F
If a closed circuit is to be provided and foundation conditions are not suitable for a tunnel, or if the required size of the waterway is too small to justify the minimum sized tunnel, a cut-and-cover conduit should be used.
True
152
T or F
An intake structure may be either submerged or extended in the form of a tower above the maximum surface water level when the controls are placed at the headworks.
False
153
Where the trashracks are inaccessible for cleaning, the velocity through the racks ordinarily shouldnot exceed 2ft/s. If a trashrack is accessible for cleaning, what can te ft/s be through the trashrack.
Up to 5ft/s
154
When open-channel outlet flow is controlled by partly open surface gates, or where top-seal radial gates or submerged slide gates control the flow, what is the formula to calculate this flow?
Q= CDL sq root 2gh
155
According to the load/ frequency relationships, a 1% change in frequency will lead to what approximate magnitude of load change in typical 10,000 MW system?
200MW
156
A governor with a 0% droop is called:
An isochronous governor
157
T or F
| Steam turbine generators typically have better governor response than hydro-electric generating units.
False
158
A control area's frequency bias setting is equal to:
All of the above: The control area's frequency response characteristic(FRC), the natural response of the control area, The AGC system's bias value.
159
All of the following are modes of AGC except;
Isochronous control
160
In which stage of a generator's response to a system disturbance is the power flow supported primarily by the generator's excitation system?
Electromagnetic energy stage
161
If system frequency were to run at 60 Hz for two consecutive hrs, how much positive time error would occur?
2.4 sec
162
A control area has a bias of -150 MW. Frequency falls .05Hz due to external disturbance. How many MW would you expect this control area to provide the disturbance?
+75
163
An isochronous governor has a droop setting of:
0%
164
What element of the power system is typically most susceptible to damage from prolonged operation at frequencies above or below 60 Hz?
Low pressure turbine strength blades
165
T or F
| The north american power system is divided into areas called interconnections.
True
166
```
Time error problem:
60Hz= No time error
Time error problem:
60Hz= No time error
Under generation= fast time error
Over generation= Slow time error
```
False
167
T or F
| All loads can be divided into two general groups, they are non-motor & motor load.
True
168
T or F
| If the voltage falls enough it will cause the motor to speed up.
False
169
Electric generators use a ___ control system to control shaft speed.
Governor
170
T or F
| The type of governors that are common on older units is a centrifugal ballhead.
True
171
T or F
Two types of utility generators that use govern control systems are steam turbine/generators and hydro turbine/ generators.
True
172
What is the Mvar production of a 50 Mvar shunt capacitor that is energized at 90% of its nominal voltage?
40.5
173
A 5% change in voltage will typically lead to what change in the total load magnitude?
3%
174
A transformer can be overexcited if exposed to:
All of the above; high voltage, low frequency, high voltage & low frequency.
175
What is the approximate Mvar/ mile production for a 345kv overhead line?
3/4
176
A 345kv transmission line operates at various voltage levels throughout the day. At which voltage level will the transmission line produce more reactive power.
360kv
177
A transmission line has 50 ohms of inductive reactance. 25 ohms of series capacitors are inserted in the line. What is the lines % series compensation?
50%
178
A transmission lines ___ is the MW loading at which the Mvar from the lines natural capacitance is equal to the Mvar the line needs to support its voltage
Surge impedance loading
179
What is the approximate Mvar/mile production for a 500kv overhead line?
2.0
180
Given a purely inductive load, what can be said about the MVA this load draws from the power system?
The load draws only Mvar
181
T or F
| A generator with spare Mvar is always a source of dynamic reactive reserve.
False
182
T or F
| The two types of power produced by the system generators are active (MW) & reactive (Mvar)
True
183
Some common causes of low voltage could be:
All of the above; Transmission line outages, motor stalling, reactive equipment outages.
184
T or F
| Generators are the primary means of controlling power system voltages.
True
185
T or F
| Excessively high voltages on the power system are less dangerous than low voltages.
False
186
There are three general frames for over voltages:
Long term, short term, transient
187
T or F
| The sudden loss of a major load can lead to short term excessive generator production of active & reactive power.
True
188
T or F
| Transformers are very susceptible to damage from sustained low voltages.
False
189
Refrigeration is the process of ___ the air defined space.
Lowering the temperature of
190
The temperature of a material decreases if the material ___ & nothing else happens that would have the opposite effect.
Contacts a cooler material
191
The two kinds of air conditioning are:
comfort and process
192
One of the physical states of matter is:
gas
193
You can cause matter to change its physical state by:
Adding or removing heat
194
Thermal energy that is directly related to the temperature of a material is called ___ heat.
Sensible
195
A temperature of 45 degrees is about the same as ___degrees C
7
196
Heat can be transferred from one place to another by the process of:
Conduction
197
The latent heat of vaporization of a substance is the amount of heat the substance absorbs as it:
Evaporates
198
A refrigeration system has been turned off for several days. It contains both liquid refrigerant & vapor. Suddenly a line containing the refrigerant breaks. What happens inside the system?
The liquid refrigerant boils.
199
From the compressor, refrigerant flows to the:
Condenser
200
The graph below is the pressure temperature chart for a refrigerant. Point ___ represents a condition of superheating.
1
201
Compared to a dry expansion evaporator, a flooded evaporator of the same size:
Is more efficient
202
The purpose of a cooling medium is to:
Remove heat from compressed refrigerant vapor.
203
An automatic expansion vlv is a metering device that maintains a constant pressure in the:
Evaporator
204
The properties of air that are important in psychometrics include.
Enthalpy
205
In a sling psychometer, the wet bulb temperature is usually lower than the dry bulb. If the difference is very small, you know the air is quite:
Humid
206
Air that is saturated is air that is at the:
Dewpoint temperature
207
Relative humidity changes if the ___ changes, but the specific humidity does not.
Dry bulb temperature.
208
To calculate the enthalpy of a sample of air, you must include:
Latent heat of the water vapor.
209
In order to remove the moisture that enters a refrigeration system during repair, you must evaluate the system by using a ___ to make all the moisture vaporize.
Vacuum pump
210
One useful method of detecting leaks in a refrigeration system involves using a(n) ___ leak detector.
Electronic
211
Relative humidity can be measured directly with a(n):
Hygrometer
212
Which of the following is a correct match between an electrical value & the instrument used to measure it?
Resistance, ohmeter
213
In the list below, identify the line that correctly match one of the classes of work are a hazard to an example of that class of hazard.
Chemical, container of refrigerant.
214
T or F
| Trapezoidal is the most accepted shape for earthen canals.
True
215
T or F
Side slopes of 3:2 for small canals & laterals and 4:2 for larger canals is generally adequate for most earth materials & should be considered when determining the side slopes of canals.
True
216
T or F
3.0fps for smaller canals up to 1.5fps for larger are the range of permissable velocities considered for sizing a canal water section.
False
217
What considerations must be made when canal construction is to utilize "cut & fill" methods?
All of the above; The water prism should be kept a safe distance into the natural ground, generally the ground water surface above the downhill cut stake should not exceed approximately 1/4 the water depth, on steep sidehills the entire water prism should be entirely in the natural ground for safe construction.
218
T or F
| Steel flumes are seldom used today due to high maintenance costs.
True
219
T or F
| Along uphill terrain cincrete bench flumes are most commonly used.
False
220
What shape of flume gives the maximum velocity for a given area?
1 that has a bottom width 2 times the depth of the water depth
221
T or F
| Encountered falling rick & debris are ideal conditions to make precast concrete pressure pipe for flume service.
True
222
T or F
| Buried precast concrete pipe & monolithic concrete pipe are considered common types of construction for siphon service.
True
223
Why is concrete pipe predominately used for canal siphons?
All of the above; Hydrostatic heads encountered are generally less than 150ft, bridges supporting canal sections across drainage channels, over highways,& railroads are generally more expensive, sizes from 12 to 96in are available in most localities.
224
T or F
| Monolithic construction is generally considered for siphons smaller than 96in in diameter
False
225
T or F
Factors that may dictate construction of elevated steel pipe siphons could be where costly rock excavation is encountered & limited space for handling river flows during construction.
True
226
What essential design features, in addition to the pipe itself, must be considered for inverted siphons?
Both A & B; Inlet and outlet transitions, blowoff structures
227
T or F
| Inlet and outlet transitions serve for the purpose of maximizing head loss & erosion damage.
False
228
T or F
| A pump type, gravity type, and pressure turnout type, are all considered blowoff structures.
True
229
T or F
When feasible, blowoffs should be located at the low points of siphon where water is drained into natural drainage channels.
True
230
T or F
To dislodge sediment & debris that may become packed in the discharge line immediately upstream of the blowoff vlvs is the purpose of the high velocity jet utilized in some gravity blowoffs.
True
231
T or F
To convey water over relatively steep slopes to lower grades & water surfaces in canals or laterals is the purpose of chute (drop)
True
232
What purpose do the controlled notch or stoplogs serve in the inlet transitions of drops and chutes?
Prevents drawdown at the entrance that would cause erosion of canal bank
233
T or F
| If max velocities are more than 3.5fps, an outlet transition is generally not needed.
False
234
T or F
By providing a depressed (submerged) section of pipe ahead of the outlet transition is how supercritical velocites are dissipated in pipe drops.
True
235
T or F
Water hammer is a reason why open type stilling pools or impact basins utilized in the design of outlet transitions for pipe chutes.
True
236
What is the preferred shape of a monolithic reinforced concrete chute?
Rectangle
237
T or F
Besides stoplogs, siphon are devices used to control water levels at the inlet transition of monolithic reinforced concrete drops & chutes.
False
238
T or F
The energy dissipated by the blocks constructed along the floor of the chute is how the conventional stilling pool is utlized in the baffled apron drop.
False
239
T or F
| Cross drainage structures serve the purpose to protect canal from damage due to moss & algae.
False
240
T or F
Relative capacity of canal with respect to drainage flows canal water surface with respect to natural ground surface dictates the need of cross drainage.
True
241
T or F
Where the canal is carried across a natural drainage channel upon an embankement is when culverts are used for cross drainage.
True
242
For large canals, what storm frequency is used to develop culvert size?
100 yr storm frequency
243
T or F
| The purpose that pipe collars serve in culvert construction is to prevent water hammer in the discharge line.
False
244
What conditions dictate use of an over chute?
All of the above; where the water surface of the canal is below the natural ground surface, where loss in grade in the canal is not permissible, are generally found economical on large canals where cross drainage flows are small by comparison to canal flows.
245
T or F
| When the amount of drainage water is large by comparison to the canal is what makes drainage inlets acceptable.
False
246
T or F
Two important factors that dictate the placement of a drainage inlet intake are the intake must be located below the max water surface elevation of the canal & at the natural ground lvl surface.
False
247
T or F
| Flow control and flow measurements are considered basic functions that a turnout must provide
True
248
What devices are generally employed for flow control @ turnouts?
Slide gates, lift gates, radial steel gates
249
T or F
| Parshall flume & cipalletti weir are 2 measuring structures predominately used in small turnouts.
True
250
T or F
Wasteways serve the purpose so that they are utilized to dispose of unwanted excess water from canals & to safely empty canals in case of canal break or other emergencies.
True
251
T or F
A sudden decrease in discharge when the siphon primes is detrimental to the waste way channel & would be considered a disadvantage of siphon spillways.
False
252
T or F
| Overflow spillway without gate control is the type of wasteway construction that is generally preferred.
False
253
T or F
| Checks serve the purpose to control the flow of water in a canal when it is operating at partial capacity.
True
254
T or F
| Two general types of checks used in small canals are those utilizing fixed concrete checks & flashboards for regulation.
True
255
T or F
| Radial gate checks of the california aqueduct always employ overflow weirs.
False
256
When conducting a sanitary survey Which of the following items would pertain to a ground water supply?
```
Distance to sources of pollution
nature of soil
slope of ground surface
slope of water table
well construction
```
257
T or F
| The best tool which can be used for managing watersheds in most cases is the regulatory process.
True
