1.
Methods of managing lakes and reservoirs used for domestic water supplies very widely depending on local situations.
Correct Answer
A. True
Explanation
The statement suggests that the methods of managing lakes and reservoirs for domestic water supplies vary depending on local situations. This implies that there is no one-size-fits-all approach to managing these water sources, as different regions may have different needs, resources, and challenges. Therefore, the statement is true.
2.
Algae remove carbon dioxide from solution and convert it into cellular material as they grow.
Correct Answer
A. True
Explanation
Algae are photosynthetic organisms that use carbon dioxide during the process of photosynthesis to produce energy and build their cellular structures. As they grow, algae remove carbon dioxide from the solution in which they are present and convert it into organic compounds, such as carbohydrates, lipids, and proteins. This process helps in reducing the concentration of carbon dioxide in the environment and is crucial for maintaining the balance of greenhouse gases. Therefore, the statement that algae remove carbon dioxide from solution and convert it into cellular material as they grow is true.
3.
Respiration by algae results in an increase in carbon dioxide in water (lowering of pH), while photosynthesis results in a decrease in water (increasing of pH)
Correct Answer
A. True
Explanation
Respiration by algae involves the release of carbon dioxide into the water, which leads to an increase in carbon dioxide concentration. This increase in carbon dioxide concentration causes the pH of the water to decrease, making it more acidic. On the other hand, photosynthesis by algae involves the absorption of carbon dioxide from the water and the release of oxygen. This process decreases the carbon dioxide concentration in the water, leading to an increase in pH and making it more alkaline. Therefore, the statement that respiration by algae results in an increase in carbon dioxide in water (lowering of pH), while photosynthesis results in a decrease in water (increasing of pH) is true.
4.
Fish kills from dead algae can be the result of the algae stimulating the gills of the fish.
Correct Answer
B. False
Explanation
Fish kills from dead algae are not caused by the algae stimulating the gills of the fish. Algae blooms can lead to fish kills due to a process called eutrophication, where the excessive growth of algae depletes oxygen levels in the water. As a result, fish and other aquatic organisms suffocate and die. This process is unrelated to the algae directly stimulating the gills of the fish.
5.
Organics released using decomposition of flooded trees and brush may contribute to increased color, chlorine demand, and trihalomethane levels following chlorination.
Correct Answer
A. True
Explanation
The decomposition of flooded trees and brush releases organics which can lead to increased color, chlorine demand, and trihalomethane levels after chlorination. This is because the organic compounds react with chlorine to form disinfection byproducts such as trihalomethanes. Therefore, it is true that the decomposition of flooded trees and brush can contribute to these effects.
6.
Regulated general use of pesticides and herbicides can cause serious problems of contamination in domestic water supply reservoirs.
Correct Answer
B. False
Explanation
The statement suggests that regulated general use of pesticides and herbicides can cause serious problems of contamination in domestic water supply reservoirs. However, the correct answer is False. This implies that regulated general use of pesticides and herbicides does not cause serious problems of contamination in domestic water supply reservoirs.
7.
Storm water runoff from highways has the potential to cause adverse impacts on reservoir water quality.
Correct Answer
A. True
Explanation
Storm water runoff from highways can indeed have adverse impacts on reservoir water quality. Highways are often paved with impermeable surfaces, such as concrete or asphalt, which prevent water from infiltrating into the ground. As a result, when it rains, the stormwater flows over the surface of the highway, picking up pollutants such as oil, gasoline, heavy metals, and sediment. This contaminated runoff then enters nearby water bodies, including reservoirs, leading to water pollution. The pollutants can harm aquatic ecosystems, affect the quality of drinking water, and pose risks to human and environmental health. Therefore, it is true that stormwater runoff from highways can cause adverse impacts on reservoir water quality.
8.
Alkalinity of the water is the principal factor that increases the effectiveness of copper sulfate.
Correct Answer
B. False
Explanation
Alkalinity of the water does not increase the effectiveness of copper sulfate. In fact, copper sulfate is more effective in water with lower alkalinity levels. Alkalinity can actually reduce the solubility and availability of copper sulfate, making it less effective. Therefore, the statement is false.
9.
After an algal bloom occurs, it is very easy to control the bloom and correct the bad effects on water quality.
Correct Answer
B. False
Explanation
After an algal bloom occurs, it is not easy to control the bloom and correct the bad effects on water quality. Algal blooms can be difficult to manage and can have severe impacts on water quality, including depleting oxygen levels, releasing toxins, and disrupting the ecosystem. Efforts to control algal blooms often require significant resources and may involve strategies such as nutrient reduction, water circulation, and treatment with algaecides. Therefore, the statement that it is very easy to control the bloom and correct the bad effects on water quality is false.
10.
Careful evaluation of reservoir monitoring must be made to determine if algae die-offs actually occur as a result of chemical application or if they simply die off due to natural circumstances.
Correct Answer
A. True
Explanation
The explanation for the given correct answer is that careful evaluation of reservoir monitoring is necessary to determine the cause of algae die-offs. It is important to determine whether the die-offs are a result of chemical application or if they occur naturally. This suggests that the statement is true, as it emphasizes the need for careful evaluation before attributing algae die-offs to chemical application.
11.
With complete destratification, surface waters are warmed and deeper waters are cooled until an equilibrium is reached and the temperatures are nearly equal from top to bottom.
Correct Answer
B. False
Explanation
The statement in the question is incorrect. Complete destratification refers to the process of mixing the water column in a body of water, which results in a more uniform temperature distribution from top to bottom. This means that surface waters are cooled and deeper waters are warmed until an equilibrium is reached. Therefore, the correct answer is False.
12.
Under freezing conditions, the heaveist (most dense) water is on the bottom and is warmer than surface water.
Correct Answer
A. True
Explanation
In freezing conditions, water molecules slow down and arrange themselves in a hexagonal lattice structure, causing the water to expand and become less dense. As a result, the heaviest (most dense) water sinks to the bottom. Additionally, because water is a good insulator, the surface water is exposed to colder temperatures and freezes first, while the water at the bottom remains relatively warmer. Therefore, it is true that under freezing conditions, the heaviest water is on the bottom and is warmer than surface water.
13.
Records provide the basic foundation upon which management programs are designed, implemented, and evaluated.
Correct Answer
A. True
Explanation
This statement is true because records are essential for management programs. Records serve as a foundation as they provide the necessary information for designing, implementing, and evaluating management programs. Without records, it would be difficult to track progress, measure success, and make informed decisions. Therefore, records play a crucial role in the overall effectiveness and efficiency of management programs.
14.
Safety hazards involved in water quality sampling may be much less than those encountered within the laboratory.
Correct Answer
B. False
Explanation
The statement suggests that safety hazards involved in water quality sampling are less than those encountered in the laboratory. However, this is not necessarily true. Water quality sampling can involve various risks such as exposure to harmful chemicals, pathogens, or physical hazards like slippery surfaces or drowning. On the other hand, laboratories have safety protocols in place to minimize risks and ensure the safety of workers. Therefore, the correct answer is False.
15.
To obtain good water quality from a water supply reservoir, it may be necessary to draw water from different levels during different seasons of the year.
Correct Answer
A. True
Explanation
To obtain good water quality from a water supply reservoir, it may be necessary to draw water from different levels during different seasons of the year. This is because different levels of the reservoir may have varying levels of sediment, pollutants, or algae growth. By drawing water from different levels, it allows for a more balanced and consistent water quality throughout the year. Additionally, different levels may have different temperature profiles, and drawing water from different levels can help maintain a suitable temperature for aquatic life.
16.
Intake structures andrelated facilities should be inspected, operated, and tested periodically, preferably at regular intervals.
Correct Answer
A. True
Explanation
Intake structures and related facilities, such as water intake systems or air intake systems, should be regularly inspected, operated, and tested. This is important to ensure their proper functioning and to identify any issues or maintenance needs. Regular inspections and testing can help prevent potential problems and ensure the efficiency and reliability of these structures and facilities. Therefore, the statement that intake structures and related facilities should be inspected, operated, and tested periodically, preferably at regular intervals, is true.
17.
What is nutrient?
Correct Answer
A. Any substance that is assimilated (taken in) by organisms and promotes growth
Explanation
A nutrient is a substance that is taken in by organisms and promotes growth. Nutrients are essential for the proper functioning and development of living organisms. They provide the necessary energy and building blocks for various physiological processes, such as growth, repair, and reproduction. Without nutrients, organisms would not be able to survive or thrive. Therefore, the correct answer is "Any substance that is assimilated (taken in) by organisms and promotes growth."
18.
What is a littoral zone?
Correct Answer
B. That portion of a body of fresh water extending from the shoreline lakeward to the limit of occupancy of rooted plants
Explanation
A littoral zone refers to the portion of a body of fresh water that extends from the shoreline lakeward to the limit where rooted plants can grow. This zone is characterized by the presence of rooted plants and is an important habitat for various aquatic organisms. It is typically shallow and receives ample sunlight, allowing for photosynthesis and promoting the growth of aquatic plants.
19.
What are the most notable impacts on water supply reservoirs as a result of increases in organic loading caused by algal blooms?
Correct Answer
A. Increased color in the water supply and a major increase in chlorine demand
Explanation
As a result of increases in organic loading caused by algal blooms, there is an increased color in the water supply. This is because the organic matter released by the algal blooms can lead to a discoloration of the water. Additionally, there is a major increase in chlorine demand. The organic matter in the water reacts with chlorine, reducing its effectiveness as a disinfectant and requiring higher levels of chlorine to maintain water quality.
20.
What causes high trihalomethane (THM) levels?
Correct Answer
D. Organic loading resulting from algal blooms and free residual chlorination
Explanation
High trihalomethane (THM) levels are caused by organic loading resulting from algal blooms and free residual chlorination. Algal blooms contribute organic matter to the water supply, which reacts with chlorine used for disinfection, forming THMs. Algae release compounds that act as precursors for THM formation. Insufficient algae present in the water supply would actually result in lower THM levels, as there would be fewer organic compounds available for reaction with chlorine. Chlorination in the absence of THM precursors or chlorination of methane from anaerobic decomposition are not the primary causes of high THM levels.
21.
Why should dissolved oxygen depletion be controlled or eliminated within the metalimnion of water supply lakes and reservoirs
Correct Answer
B. To eliminate or control iron, manganese, and hydrogen sulfide problems
Explanation
Dissolved oxygen depletion within the metalimnion of water supply lakes and reservoirs should be controlled or eliminated to eliminate or control iron, manganese, and hydrogen sulfide problems. When dissolved oxygen levels are low, these elements can become more soluble and release into the water, leading to issues such as discoloration, foul odor, and potential health risks. By maintaining adequate levels of dissolved oxygen, the solubility of these elements can be reduced, preventing or minimizing these problems.
22.
What is the primary purpose of any watershed management program?
Correct Answer
B. To control, minimize, or eliminate any practice within the watershed area that are harmful to water quality
Explanation
The primary purpose of any watershed management program is to control, minimize, or eliminate any practices within the watershed area that are harmful to water quality. This involves implementing strategies and measures to protect and improve the quality of water resources within the watershed, such as reducing pollution, managing land use practices, and implementing conservation practices. By doing so, the program aims to ensure the long-term sustainability and health of the watershed ecosystem and the water supply it provides.
23.
Why is copper sulfate effective as an algicide at low levels of alkalinity?
Correct Answer
D. Because of the high levels of biologically active copper
Explanation
Copper sulfate is effective as an algicide at low levels of alkalinity because of the high levels of biologically active copper. Copper ions in copper sulfate are toxic to algae and can inhibit their growth. At low levels of alkalinity, the copper ions are more readily available and can easily interact with the algae, leading to their suppression or death. Therefore, the presence of high levels of biologically active copper in copper sulfate makes it effective as an algicide at low alkalinity levels.
24.
Why must the operator have a reservoir monitoring program in reservoirs where algae are a potential problem?
Correct Answer
A. To anticipate a possible algal bloom
Explanation
The operator must have a reservoir monitoring program in reservoirs where algae are a potential problem in order to anticipate a possible algal bloom. This is important because algal blooms can lead to various issues such as the release of toxins, depletion of oxygen in the water, and negative impacts on aquatic life. By monitoring the reservoir regularly, the operator can detect early signs of algal growth and take necessary actions to prevent or mitigate the bloom, ensuring the safety and health of the water source.
25.
Which chemical is being considered as an alternative algicide to copper sulfate?
Correct Answer
C. Hydrogen-peroxide-based herbicides
Explanation
Hydrogen peroxide-based herbicides are being considered as an alternative algicide to copper sulfate. This is because hydrogen peroxide has shown effectiveness in controlling algae growth. It acts by releasing oxygen, which disrupts the metabolic processes of the algae and inhibits its growth. Additionally, hydrogen peroxide is less toxic to aquatic organisms and has lower environmental impact compared to copper sulfate. Therefore, hydrogen peroxide-based herbicides are a viable alternative for controlling algae without the negative effects associated with copper sulfate.
26.
What is destratification?
Correct Answer
A. The development of vertical mixing within a lake or reservoir to eliminate separate layers of temperature, plant, or animal life
Explanation
Destratification refers to the development of vertical mixing within a lake or reservoir in order to eliminate separate layers of temperature, plant, or animal life. This process helps to distribute oxygen, nutrients, and other essential elements evenly throughout the water body, creating a more homogeneous environment. By reducing stratification, destratification promotes a healthier ecosystem and can improve water quality.
27.
How is destratification accomplished?
Correct Answer
D. By inducing vertical mixing within reservoir
Explanation
Destratification is the process of mixing the layers of water in a reservoir to eliminate stratification, which is the separation of water into distinct layers based on temperature and density. The correct answer states that destratification is accomplished by inducing vertical mixing within the reservoir. This means that mechanisms are used to mix the water vertically, such as the use of pumps or diffusers, to break up the layers and create a more uniform water temperature and density throughout the reservoir.
28.
Why should silt surveys of most reservoirs be conducted periodically?
Correct Answer
C. To get an updated measure of silting as it affects available water storage
Explanation
Periodic silt surveys of reservoirs should be conducted to obtain an updated measure of silting as it affects available water storage. This is important because the accumulation of silt over time can reduce the capacity of the reservoir to hold water, leading to decreased water availability. By conducting regular surveys, authorities can monitor the rate of silting and take necessary measures to prevent excessive accumulation, such as dredging or sediment management strategies. This helps ensure that the reservoir can continue to provide an adequate water supply for various purposes.
29.
What is the main safety hazard encountered during reservoir sampling?
Correct Answer
A. Drowning
Explanation
During reservoir sampling, the main safety hazard encountered is drowning. Reservoir sampling involves collecting water samples from bodies of water such as lakes, rivers, or reservoirs. This process can be dangerous as it involves being in or near the water, which increases the risk of drowning. Therefore, it is crucial to take appropriate safety measures and precautions to prevent accidents and ensure the safety of individuals involved in reservoir sampling.
30.
Why is it important to keep record of when and under what condition failures or malfunctions of intake facilities occur?
Correct Answer
D. It may be possible to take preventive action
Explanation
Keeping a record of when and under what condition failures or malfunctions of intake facilities occur is important because it allows for the identification of patterns or trends. By analyzing these records, it may be possible to identify potential causes of failures or malfunctions and take preventive action to avoid similar incidents in the future. This can help in improving the overall efficiency and reliability of the intake facilities, reducing downtime, and minimizing the risk of disruptions to the water supply.
31.
Which items occuring within a reservoir's drainage area may lead to deterioration of water quality?
Correct Answer(s)
A. Agricultural runoff
B. Drainage from mining areas
C. Grazing of livestock
D. Industrial discharges
E. Runoff from urban areas
Explanation
The items listed in the answer options can all contribute to the deterioration of water quality within a reservoir's drainage area. Agricultural runoff can contain pesticides, fertilizers, and other chemicals that can contaminate the water. Drainage from mining areas can introduce heavy metals and other pollutants into the water. Grazing of livestock can lead to the deposition of animal waste and bacteria in the water. Industrial discharges can release various pollutants and toxins. Runoff from urban areas can carry pollutants such as oil, chemicals, and litter into the water. Overall, all of these factors have the potential to negatively impact the water quality in a reservoir's drainage area.
32.
Which common water quality problems in domestic water supply reservoirs may be related to algal blooms?
Correct Answer(s)
A. Dissolved oxygen depletion
B. Increased pH (which reduces chlorination efficiency)
C. Organic loading
D. Shortened filter runs of complete treatment plants
E. Taste and odor problems
Explanation
Algal blooms in domestic water supply reservoirs can lead to various water quality problems. Dissolved oxygen depletion occurs when algae consume oxygen during photosynthesis, leading to low oxygen levels in the water. Increased pH is caused by algal photosynthesis, which can reduce the efficiency of chlorination, a common method of disinfection. Algal blooms can also result in organic loading, as dead algae and other organic matter accumulate in the water. This can lead to shortened filter runs in treatment plants, as more frequent cleaning is required. Additionally, algal blooms can cause taste and odor problems in the water, making it unpleasant to consume.
33.
Reservoirs located in mountainous areas where snowmelt is the major source of runoff may experience increases in which water quality problems during snowmelt?
Correct Answer(s)
B. Nutrient loading
C. Organic loading
E. Turbidity
Explanation
Reservoirs located in mountainous areas where snowmelt is the major source of runoff may experience increases in nutrient loading, organic loading, and turbidity during snowmelt. This is because the melting snow carries with it nutrients, such as nitrogen and phosphorus, from the surrounding land. Additionally, the runoff can pick up organic matter, such as leaves and debris, and sediment, which can increase turbidity in the reservoir. These factors can negatively impact water quality and potentially lead to issues such as algal blooms and decreased oxygen levels.
34.
Which factors are critical in order for a lake or reservoir water quality management program to be feasible?
Correct Answer(s)
C. Must be economically justifiable
D. Must be prepared for each specific reservoir
E. Must be technically justifiable
Explanation
A lake or reservoir water quality management program needs to be economically justifiable, as it should be financially feasible and cost-effective to implement. It must also be prepared for each specific reservoir, considering its unique characteristics and requirements. Additionally, the program must be technically justifiable, meaning that it should be based on sound scientific and engineering principles to effectively address the water quality issues. These factors are critical for ensuring the success and sustainability of the management program.
35.
Which items are methods of reservoir management?
Correct Answer(s)
A. Algae control by chemical methods
D. Removal pf trees and brush from areas to be flooded
E. Watershed management
Explanation
The methods of reservoir management mentioned in the answer are algae control by chemical methods, removal of trees and brush from areas to be flooded, and watershed management. These methods are all related to the maintenance and preservation of the reservoir's ecosystem and water quality. Algae control by chemical methods helps in preventing excessive algae growth that can affect water quality. Removal of trees and brush from areas to be flooded is important to prevent debris from accumulating in the reservoir and causing blockages. Watershed management involves managing the land and water resources within the reservoir's catchment area to ensure the long-term sustainability of the reservoir.
36.
During the runoff period following a wildfire, what types of pollutants may enter the reservoir?
Correct Answer(s)
B. Large amount of debris
D. Nutrients
E. Silt
Explanation
During the runoff period following a wildfire, a large amount of debris, nutrients, and silt may enter the reservoir. Wildfires can cause vegetation and soil to burn, leading to an increased amount of debris such as ash and charred materials being washed into the reservoir during rainfall events. Nutrients from the burned vegetation and soil can also be carried by the runoff into the reservoir. Additionally, the erosion caused by the fire can result in the transport of silt, which can further contaminate the reservoir.
37.
Which adverse impacts can occur if an algal bloom is allowed to become intense before chemicals are applied?
Correct Answer(s)
A. A large algae die-off may occur and cause an increase in tastes and odors
B. Fish die-offs could result from dead algal bodies clogging fish gills of from low dissolved oxygen levels
E. Rate of oxygen depletion in the deeper waters will probably be increased
Explanation
If an algal bloom is allowed to become intense before chemicals are applied, a large algae die-off may occur. This can lead to an increase in tastes and odors in the water. Additionally, fish die-offs could result from dead algal bodies clogging fish gills or from low dissolved oxygen levels. Moreover, the rate of oxygen depletion in the deeper waters will probably be increased.
38.
Which factors influence the concentration of copper sulfate needed for effective control of any particular algal bloom?
Correct Answer(s)
A. Alkalinity of the water
B. Amount of algae
C. pH of the water
D. Species of algae
E. Water temperature
Explanation
The concentration of copper sulfate needed for effective control of any particular algal bloom is influenced by several factors. The alkalinity of the water affects the effectiveness of copper sulfate, as higher alkalinity levels require higher concentrations of copper sulfate. The amount of algae present also plays a role, with larger blooms requiring higher concentrations of copper sulfate. The pH of the water affects the solubility of copper sulfate, with lower pH levels requiring higher concentrations. The species of algae present can also impact the effectiveness of copper sulfate, as different species may have varying sensitivities. Lastly, water temperature can influence the effectiveness of copper sulfate, with higher temperatures often requiring higher concentrations to achieve control.
39.
Why are full and accurate records an important part of any chemical algae control program?
Correct Answer(s)
A. For designing new or revising existing programs
C. For showing compliance with federal, state, and local regulations
D. To evaluate current and historical treatment programs
Explanation
Full and accurate records are important for designing new or revising existing programs because they provide valuable information on the effectiveness of previous treatments and help in making informed decisions for future control measures. They are also necessary for showing compliance with federal, state, and local regulations, as authorities may require documentation of the chemicals used and their application rates. Additionally, records are essential for evaluating the success of current and historical treatment programs, allowing for adjustments and improvements to be made if necessary.
40.
If local authorities approve certain recreational activities on reservoir ice surfaces, operators should insist on provision of which safeguards against possible pollution?
Correct Answer(s)
A. Adequate toilet facilities and proper care of these facilities
B. Leak proof waste containers
C. Proper and close supervision of activities on the ice
E. Time limits on activities on the ice
Explanation
Operators should insist on the provision of adequate toilet facilities and proper care of these facilities to prevent pollution caused by improper disposal of waste. Leak proof waste containers should also be provided to ensure that any waste generated during recreational activities on the reservoir ice surfaces does not leak and contaminate the environment. Proper and close supervision of activities on the ice is necessary to ensure that participants do not engage in activities that could cause pollution. Time limits on activities on the ice can help prevent overuse and minimize the potential for pollution.
41.
A reservoir maintenance program should consider which items?
Correct Answer(s)
A. Before draining a reservoir for maintenance, determine when, where, and how you will discharge the water in the reservoir
B. Control shoreline vegetation such as weeds and cattails
C. Lined reservoirs may have to be drained only during periods of low groundwater levels
D. Lower the water level fairly slowly, because if the water level drops too quickly, the embankments may slip out and be damaged
E. Mechanical or manual techniques can be used to remove and control vegetation
Explanation
A reservoir maintenance program should consider several factors. Firstly, before draining a reservoir for maintenance, it is important to determine when, where, and how the water will be discharged from the reservoir. This ensures that the water is properly managed and does not cause any issues. Secondly, controlling shoreline vegetation such as weeds and cattails is crucial to maintain the reservoir's functionality and prevent any blockages. Additionally, lined reservoirs may only need to be drained during periods of low groundwater levels to minimize the impact on the surrounding environment. Lowering the water level slowly is essential to prevent any damage to the embankments, as dropping the water level too quickly can cause them to slip out. Lastly, vegetation removal and control can be achieved through mechanical or manual techniques to maintain the reservoir's ecosystem.
42.
What types of laboratory analyses may best be performed for small reservoir management agency by an outside or commercial laboratory?
Correct Answer(s)
A. Nutrients analyses
B. Pesticides analyses
C. Radioactivity analyses
D. Toxic minerals and heavy metal analyses
E. Trihalomethanes analyses
43.
If algal blooms are a problem in a particular reservoir, the laboratory should be able to develop what kind of information?
Correct Answer(s)
A. Extent of algal blooms
C. Intensity of algal blooms
D. Major species of algae involved in any given bloom
E. Water quality problems that develop as a result of the bloom
Explanation
The laboratory should be able to develop information on the extent of algal blooms, intensity of algal blooms, major species of algae involved in any given bloom, and water quality problems that develop as a result of the bloom. This information is crucial for understanding and managing the algal blooms in the reservoir. By determining the extent and intensity of the blooms, the laboratory can assess the severity of the problem. Identifying the major species of algae involved helps in understanding their characteristics and potential impacts. Finally, understanding the water quality problems resulting from the blooms allows for targeted mitigation strategies.
44.
To be prepared for changing reservoir conditions, the water treatment plant operator should take responsibility for which items?
Correct Answer(s)
A. Be alert for onshore winds
B. Be prepared to make necessary changes in treatment plant operation to combat any sudden increases in taste and odor problems
C. Do everything possible to keep any water with bad taste or odor that gets through the treatment plant from getting out into the distribution system
D. Maintain a log of wind direction and velocity
E. Maintain close surveillance of threshold odor test results
Explanation
The water treatment plant operator should be alert for onshore winds because they can bring in contaminants or pollutants that can affect the quality of the water. They should also be prepared to make necessary changes in the treatment plant operation to address any sudden increases in taste and odor problems. Additionally, they should do everything possible to prevent water with bad taste or odor from entering the distribution system. Maintaining a log of wind direction and velocity can help track potential sources of contamination, and close surveillance of threshold odor test results can help identify any changes in water quality.
45.
The type of screen, trash rack, or log stop used in a given intake structure depends on which factors?
Correct Answer(s)
A. Depth at which the inlets are located
B. Frequency and intensity of algal scum or algal mass accumulations
C. Location of the intake structure in relation to where debris accumulates in the reservoir or stream
D. Quantity and type of debris encountered
E. Size, depth of distribution, and number of fish, crayfish, and other forms of aquatic life?
Explanation
The type of screen, trash rack, or log stop used in a given intake structure depends on factors such as the depth at which the inlets are located, the frequency and intensity of algal scum or algal mass accumulations, the location of the intake structure in relation to where debris accumulates in the reservoir or stream, the quantity and type of debris encountered, and the size, depth of distribution, and number of fish, crayfish, and other forms of aquatic life.
46.
What is the surface area of a rectangular settling basin 50 feet long and 10 feet wide?
Correct Answer
B. 500 square feet
Explanation
The surface area of a rectangular settling basin can be calculated by multiplying its length by its width. In this case, the length is given as 50 feet and the width is given as 10 feet. Therefore, the surface area would be 50 feet multiplied by 10 feet, which equals 500 square feet.
47.
What is the surface area of a circular clarifier 55 feet in diameter?
Correct Answer
D. 2,375 square feet
Explanation
The surface area of a circular clarifier can be calculated using the formula for the area of a circle, which is A = πr^2. In this case, the diameter of the clarifier is given as 55 feet, so the radius would be half of that, which is 27.5 feet. Plugging this value into the formula, we get A = π(27.5)^2. Evaluating this expression gives us approximately 2375 square feet. Therefore, the correct answer is 2,375 square feet.
48.
What is the volume in cubic feet of a rectangular settling basin 8 feet deep, 12 feet wide, and 60 feet long?
Correct Answer
E. 5,800 cu ft
Explanation
The volume of a rectangular settling basin can be calculated by multiplying its length, width, and depth. In this case, the length is given as 60 feet, the width is given as 12 feet, and the depth is given as 8 feet. Therefore, the volume can be calculated as 60 ft x 12 ft x 8 ft = 5,760 cubic feet. Since the closest option to this value is 5,800 cubic feet, the correct answer is 5,800 cu ft.
49.
What is the volume in cubic feet of a circular clarifier 8 feet deep and 50 feet in diameter?
Correct Answer
C. 15,700 cu ft
Explanation
The volume of a circular clarifier can be calculated using the formula V = πr^2h, where V is the volume, π is a mathematical constant (approximately 3.14159), r is the radius of the circular clarifier (which is half of the diameter), and h is the depth. In this case, the diameter is given as 50 feet, so the radius is 25 feet. The depth is given as 8 feet. Plugging these values into the formula, we get V = 3.14159 * (25^2) * 8 = 15,707.96 cubic feet, which can be rounded to 15,700 cubic feet.
50.
How many pounds of copper sulfate will be needed to dose a reservoir with 0.6 mg/L copper? The reservoir volume is 25 million gallons. The copper sulfate is 25 percent copper.
Correct Answer
C. 500 pounds
Explanation
To calculate the amount of copper sulfate needed, we need to find the amount of copper required to achieve a concentration of 0.6 mg/L in a 25 million gallon reservoir.
First, we convert the volume of the reservoir to liters: 25 million gallons = 94,635,294 liters.
Next, we calculate the total amount of copper needed: 0.6 mg/L x 94,635,294 L = 56,781,176.4 mg.
Since the copper sulfate is 25% copper, we divide the total amount of copper needed by 0.25: 56,781,176.4 mg / 0.25 = 227,124,705.6 mg.
Finally, we convert the amount of copper sulfate from milligrams to pounds: 227,124,705.6 mg / 453,592.37 = 500 pounds.
Therefore, 500 pounds of copper sulfate will be needed to dose the reservoir with 0.6 mg/L copper.