Water Distribution Exam 2024 Questions and Answers 100% Correction., Exams of Water Resources Planning and Management

Download Water Distribution Exam 2024 Questions and Answers 100% Correction. and more Exams Water Resources Planning and Management in PDF only on Docsity!

Water Distribution Exam 2024 Questions

and Answers 100% Correction.

Potable water may be defined as? - ANSWER-Any water that according to recognized standard is safe for human consumption. Preventing surface contamination from entering a drinking water well is purpose of the?

• ANSWER-Sanitary Seal Pure water will exhibit a pH value of? - ANSWER-7. A pH reading of 6.0 units indicate that the water is? - ANSWER-Slightly Acidic In drinking water quality, "TDS" is the abbreviation for? - ANSWER-Total Dissolved Solids The MBAS method is used to determine levels of which of the following drinking water constituents? - ANSWER-Forming Agent In water quality, "mg/L" means? - ANSWER-Part per million The term "clearwell" refers to a? - ANSWER-Reservoir at the outlet of a water treatment plant. A mechanical device often employed to prevent the over-filling and/ on over-draining of distribution system reservoir is the? - ANSWER-Altitude Valve The primary cause of water quality deterioration in distribution system is? - ANSWER- Water age The term "Springline" applies to? - ANSWER-The midline of a pipeline When possible, a water main should be tapped while still pressurized to? - ANSWER- Minimize contamination risk A connection made into a water main that is full of under pressure is called? - ANSWER-a wet tap A special valve that is used almost exclusively to facilitate making connections to pipeline is the? - ANSWER-Corporation Stop The most commonly used meter on small domestic services? - ANSWER-Nutating Disk Meter

Of the following, which is a positive displacement flow rate meter? - ANSWER-Nutating Disk A Nutating disk is found in certain? - ANSWER-Water meter A pump is experiencing back-spin after it is shut down. What is the most likely cause? - ANSWER-Malfunction check valve When fully open, which of the following valve types will have the highest friction loss? - ANSWER-Glove valve The main purpose of a butterfly valve in a water distribution system is for? - ANSWER- Isolation The most likely means of connecting two pressure zone is through a? - ANSWER- Pressure reducing valve The purpose of an air relief valve is to? - ANSWER-Protect the pipe system Which of the following devices is routinely used to reduce system pressure? - ANSWER-Globe valve A venture is a device that is used to? - ANSWER-Measured water flow The most common valve in water distribution system is the? - ANSWER-Gate valve Venturi meters operate under the principle of? - ANSWER-Pressure differential An auxiliary valve is always located adjacent to a? - ANSWER-Fire Hydrants If you encounter a liquid chlorine leak in a one-ton container. What action should you take first, to reduce the severity of the leak? - ANSWER-Rotate the container to place the leak at the top The most commonly used water disinfectant in the United States is? - ANSWER- Chlorine When collecting a distribution system sample, the water should be allowed to run for a period of time prior to sample collection. - ANSWER-This period of time is As long as necessary to permit clearing of the service line Sample bottles which are furnished by a certified laboratory for collection of bacteriological same? - ANSWER-Ready to use

A device that automatically shuts off flow into an elevated storage tank when water level in the tank reaches a preset level is termed a? - ANSWER-Altitude valve Before digging, what should an operator does? - ANSWER-Call dig alert if digging and must notify 48 hrs How must the new water main be flush? - ANSWER-New water main pipe must be flush 24 hrs. The presence of coliform bacteria in a distribution system Indicates? - ANSWER-that pathogenic organisms may be present also Most below-ground-level storage tanks are constructed of? - ANSWER-Concrete When fully open, which of the following will have the lowest friction loss? - ANSWER- Gate valve Enclosed, open, and semi-closed are terms used for the designation and selection of? - ANSWER-Impellers "Blackflow Device" is a term used to describe a device that? - ANSWER-Prevents backflow of potentially contaminated source into drinking water A compound meter is a device which? - ANSWER-Provides accurate reading over a wide range of flows The packing gland serves many functions in a centrifugal pump. Among these, it? - ANSWER-Keeps gritty material from entering the packing boxes. Which of the following is a positive displacement pump? - ANSWER-Reciprocating pump What information must be on a warming tag attached to a locked-out switch? - ANSWER-Signature of the person who locked out the switch and who will remove it A chlorine leak can be detected by? - ANSWER-Applying ammonia vapor Red water problems are due primary to? - ANSWER-Iron When testing a distribution system for chlorine residual, you should? - ANSWER-Test samples fro several different points A normal buried valve located on a street water main and leading to a water service is known as a? - ANSWER-Corporation Stop

A new water main should be flushed, disinfected at 50mg/L and held at above 25 mg/L for at least? - ANSWER-24 hours The fusible plug that is in all chlorine containers? - ANSWER-Should never be removed or tampered with An example of a pressure-differential type water is a? - ANSWER-Venturi meter The only blackflow prevention device approved for all application is the? - ANSWER- Reduced pressure zone device A cross-connection means? - ANSWER-A connection between potable water and "unapproved" water supplies The packing gland serves many functions in a centrifugal pump. Among these, it? - ANSWER-Keeps gritty material from entering the packing box. The rotating element in a centrifugal pump is commonly called the? - ANSWER-Impeller A water-bearing formation in the soil is referred to as? - ANSWER-An aquifer The bubbles formed in a positive multiple tube fermentation test are? - ANSWER- Carbon Dioxide The distance between the static water level and the pumping water level is termed the?

• ANSWER-Drawdown. Entry into an atmosphere with high concentrations of chlorine gas requires? - ANSWER-A self-contained breathing apparatus. The height to which water will rise in wells located in an artesian aquifer is called the? - ANSWER-Piezometric Surface. Hardness in water is due to dissolved? - ANSWER-Calcium and Magnesium. A primary drinking water regulation is based upon - ANSWER-Health effects. Algae growth in untreated surface water reservoirs can be reduced by applying? - ANSWER-Copper Sulfate. The layer of a stratified lake that is most likely to be impacted by algae is called the? - ANSWER-Epilimnion. Secondary drinking water standards are generally based upon? - ANSWER-Aesthetic Properties.

An aquifer is usually composed of? - ANSWER-Sand and Gravel. A clay layer in the soil resists the flow of groundwater. Such a layer is called An? - ANSWER-Aquitard. What is one of the primary objectives for the operation of a water distribution system? - ANSWER-All of the above The primary origin of coliforms in water supplies is? - ANSWER-Fecal contamination by warm-blooded animals What is the recommended minimum water pressure in a distribution system at any time, including fire flow conditions? - ANSWER-20 psi The definition of a public water system in the Safe Drinking Water Act is a system that supplies piped water for human consumption that has at least: - ANSWER-15 service connections or serves 25 or more persons for 60 or more days a year Pieces of metal that are designed to corrode instead of the facility they are designed to protect are called? - ANSWER-Sacrificial anodes The federal Lead and Copper Rule requires that samples be collected? - ANSWER- From Residential Taps The term Corrective Maintenance is? - ANSWER-Work performed in response to a failure Any of the bacteria within the coliform bacterial group can be considered as? - ANSWER-An indicator of the potential presence of pathogenic fecal organisms In order to preserve the ability to locate non-metallic pipes in the future new installations typically require the installation of? - ANSWER-Tracer wire A primary consideration in determining the number and location of sampling points in a water distribution system are that they should be? - ANSWER-Representative of each source and condition within the system Cathodic protection means protection against? - ANSWER-Corrosion What is the term for water samples collected at an individual location at a specific time?

• ANSWER-Grab samples Disease causing organisms such as bacteria and viruses are known as? - ANSWER- Pathogens

Which of the following devices are typically used to measure instantaneous distribution system pressure? - ANSWER-Pressure Gauge What does the Total Coliform Rule require in response to a positive sample for Total Coliforms? - ANSWER-Repeat Sampling The metal component that is protected from corrosion is called the? - ANSWER- Cathode The performance curve of a pump reflects? - ANSWER-All of the above As flow increases, friction losses in a water distribution pipeline? - ANSWER-Increase What is the difference between a primary standard and a secondary standard? - ANSWER-Primary standards refer to substances that are thought to pose a threat to human health; secondary standards refer to aesthetic water quality Which of the following devices can be used to measure distribution system pressure over a period of time? - ANSWER-Pressure Recorder With ductile-iron pipe, the best joint to use when the installation is aboveground where rigidity is required, such as in water treatment plants and pumping stations, is a? - ANSWER-Flanged joint A pump assembly where the impeller is mounted directly on the shaft of the motor driving the pump is referred to as? - ANSWER-Close coupled The hydraulic grade at any point in a distribution system is made up of the following two components? - ANSWER-Elevation and pressure head A water company's average day demand is determined by dividing the? - ANSWER- Total water use for a year by 365 days Which of the following is not a reason for a water distribution system flushing program?

• ANSWER-Increase Water age Which type of pipe most commonly requires a cathodic protection system? - ANSWER- Steel pipe In a double suction centrifugal pump? - ANSWER-Water enters both sides of the impeller What does not materially affect the head loss due to friction in a given length of pipe? - ANSWER-Water hardness

Complaints of poor water quality will most likely occur in which type of water main layout? - ANSWER-Tree Lead in drinking water is primarily the result of? - ANSWER-Corrosion within the distribution system service lines and residential plumbling Pipeline beam breaks are caused by? - ANSWER-Uneven support on the bottom of the pipe The maximum theoretical suction life of a centrifugal pump at sea level is approximately? - ANSWER-34 feet The direction of the slope of a hydraulic grade line during flow conditions? - ANSWER-Is always downward A POSITIVE bacteriological sample means? - ANSWER-Presence of bacteriological contamination Water hammer is most likely caused by? - ANSWER-Closing a valve too fast Pressure in a pipeline may be affected by? - ANSWER-Fiction and elevation What exterior forces should be considered when selecting distribution piping? - ANSWER-All of the above If the discharge pressure of a centrifugal pump is increased and the pump speed remains the same the pump discharge flow output will? - ANSWER-Decrease Static head is the? - ANSWER-Pressure due only to the depth or elevation of water What is the minimum length of time water must remain motionless in service lines prior to first-draw residential lead sampling? - ANSWER-6 hours In order to comply with Regional Water Quality Control Board requirements, prior to entering a storm drain or receiving water, water from fire hydrant or main line flushing operations must be? - ANSWER-Dechlorinated A bell and spigot connection is used in what type of pipe joint? - ANSWER-Push on joint What is not a component of the total head required to be produced by a pump? - ANSWER-Atmospheric Pressure Minor losses are a measurement of head loss in the system due to? - ANSWER-Friction loss in pipe fittings

By regulation which type of water source of supply requires treatment by filtration prior to delivery to water consumers? - ANSWER-Surface water Peak flows in a water distribution system are driven by? - ANSWER-All of the above Ductile iron pipe is typically protected from corrosion by? - ANSWER-Wrapping it in polyethylene plastic Pressure in a pump is created by? - ANSWER-Converting velocity head to pressure head as water flows around a volute with an enlarging area When comparing friction loss in water pipes, a larger Hazen-Williams C-factor value indicates the pipe is? - ANSWER-Smoother inside Which of the following well types is most protected from surface contamination? - ANSWER-Artesian well Check valves are used to? - ANSWER-Permit flow in only one direction Standard fire hydrants should not be installed on water mains smaller than? - ANSWER-6 inches in diameter What is the term for a framework of wood or metal installed to prevent caving of trench walls? - ANSWER-Shoring Which of the following best defines the term Drawdown? - ANSWER-Change in water elevation from the static level to the pumping level Diaphragm control valves are operated by? - ANSWER-Adding or removing water from the cover above the diaphragm The underground pipe fitting connecting the inlet pipe to a fire hydrant is called the? - ANSWER-Bury Operators must have unobstructed access to a ladder for escape from a trench within what distance? - ANSWER-25 feet If there is sufficient pressure for water to flow from a well that taps an aquifer the well is called? - ANSWER-A flowing artesian well Why should isolation valves be installed at frequent intervals in distribution systems? - ANSWER-So that small sections of water main may be shut off for maintenance Which type of hydrant has no main valve but has a separate valve for each nozzle? - ANSWER-Wet barrel

As a general rule, water pipes should be separated from sewer pipes by a horizontal distance of? - ANSWER-10 feet The water table is defined as? - ANSWER-Upper surface of the groundwater What type of valve is used to vent air that has accumulated in a water pipeline? - ANSWER-Air relief valve What type of fire hydrant is pictured below? - ANSWER-Dry Barrel (Has top Cap) What is the purpose of thrust blocks and anchors in a water distribution system? - ANSWER-Restrain pipe joints, elbows, tees, and crosses from coming apart as a result of the force created when water changes direction