Soil Erosion & Sedimentation Control Training - Unit 2
Study exam for the Soil Erosion and Sedimentation Control Training - Unit 2
Questions and Answers
- 1.
Runoff is rain the does not _________________ into the soil.
- A.
Melt
- B.
Infiltrate
- C.
Absorb
- D.
Erode
Correct Answer
B. InfiltrateExplanation
Runoff is rainwater that does not infiltrate or seep into the soil. Instead, it flows over the surface of the ground, potentially causing erosion and carrying pollutants with it.Rate this question:
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- 2.
Without proper planning, construction generally results in an _________________ in runoff.
- A.
Decrease
- B.
Increase
- C.
Overflow
- D.
Underflow
Correct Answer
B. IncreaseExplanation
Without proper planning, construction generally results in an increase in runoff. This can be attributed to various factors such as the removal of vegetation and natural drainage systems, which leads to a decrease in infiltration and an increase in surface runoff. Additionally, the creation of impervious surfaces like roads and buildings further exacerbates the issue by preventing water from being absorbed into the ground. As a result, there is a higher volume of water flowing off the construction site, leading to an increase in runoff.Rate this question:
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- 3.
An increase in runoff generally results in an increase in the amount of ____________ generated.
- A.
Vegetation
- B.
Compaction
- C.
Sediment
- D.
Infiltration
Correct Answer
C. SedimentExplanation
An increase in runoff generally results in an increase in the amount of sediment generated. Runoff refers to the water that flows over the surface of the land and into rivers, lakes, or other bodies of water. When there is more runoff, there is a higher chance of erosion occurring, which leads to the transportation and deposition of sediment. Sediment can include soil particles, rocks, and other debris that is carried by the runoff. Therefore, an increase in runoff often leads to an increase in the amount of sediment generated.Rate this question:
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- 4.
Runoff is generally increased during and after construction due to: (choose 3)
- A.
Surface roughing
- B.
Grading removes vegetation
- C.
Grading compacts the soil
- D.
Staging construction activities
- E.
Construction increases the amount of impervious area
Correct Answer(s)
B. Grading removes vegetation
C. Grading compacts the soil
E. Construction increases the amount of impervious areaExplanation
During construction, grading is often done to level the ground or create slopes. This process involves removing vegetation, which can contribute to increased runoff as there are no longer plants to absorb water. Additionally, grading compacts the soil, reducing its ability to absorb water and increasing the amount of runoff. Finally, construction itself often involves the creation of impervious surfaces such as roads, parking lots, and buildings, which further increase the amount of runoff as water cannot infiltrate into the ground.Rate this question:
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- 5.
Several construction practices that minimize runoff and control erosion are: (choose 3)
- A.
Grading to remove vegetation
- B.
Seed and mulch all bare areas
- C.
Grading to compact the soils
- D.
Staging construction activities
- E.
Divert runoff around the graded area
Correct Answer(s)
B. Seed and mulch all bare areas
D. Staging construction activities
E. Divert runoff around the graded areaExplanation
The correct answer is seed and mulch all bare areas, staging construction activities, and divert runoff around the graded area. These practices are effective in minimizing runoff and controlling erosion during construction. Seed and mulch help to stabilize the soil and prevent erosion by providing ground cover. Staging construction activities involves carefully planning and sequencing construction tasks to minimize disturbance to the site and reduce erosion. Diverting runoff around the graded area helps to prevent excess water from flowing over bare soil and causing erosion. By implementing these practices, construction sites can reduce the negative environmental impacts of runoff and erosion.Rate this question:
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- 6.
Several construction practices that minimize runoff and control erosion are: (choose 2)
- A.
Preserve vegetative buffer areas
- B.
Construct more impervious areas
- C.
Surface roughening
- D.
Construct check dams
Correct Answer(s)
A. Preserve vegetative buffer areas
C. Surface rougheningExplanation
Preserving vegetative buffer areas helps to minimize runoff and control erosion by maintaining natural vegetation along water bodies, which helps to absorb and filter runoff, reducing the amount of sediment and pollutants that enter the water. Surface roughening involves creating rough surfaces on the ground, such as through grading or adding mulch, which helps to slow down and retain water, reducing runoff and erosion. Constructing more impervious areas and check dams, on the other hand, would not minimize runoff or control erosion, as impervious surfaces prevent water from infiltrating the ground and check dams are used to control water flow rather than minimize runoff.Rate this question:
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- 7.
______________, sometimes called phasing is part of scheduling. This is where grading and stablization are finished in one area before proceeding to the next.
- A.
Roughening
- B.
Compacting
- C.
Staging
- D.
Mulching
Correct Answer
C. StagingExplanation
Staging, sometimes called phasing, is part of scheduling. This involves completing grading and stabilization in one area before moving on to the next.Rate this question:
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- 8.
Care must be taken not to exceed ______________ that will erode the diversion channel.
- A.
Levels
- B.
Velocities
- C.
Density
- D.
Infiltration
Correct Answer
B. VelocitiesExplanation
The correct answer is "velocities". When constructing a diversion channel, it is important to control the flow velocities of water to prevent erosion. If the velocities are too high, it can cause the channel to erode and potentially fail. Therefore, care must be taken to ensure that the velocities of water flowing through the diversion channel are within acceptable limits to maintain its stability and functionality.Rate this question:
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- 9.
Overland flow that is diverted must be disposed of without causing ___________.
- A.
Roughening
- B.
Sedimentation
- C.
Erosion
- D.
Compaction
Correct Answer
C. ErosionExplanation
When overland flow is diverted, it must be disposed of without causing erosion. Erosion refers to the process of wearing away or removal of soil or rock by wind, water, or other natural agents. If the diverted flow causes erosion, it can lead to the loss of valuable topsoil, damage to vegetation, and potential sedimentation in nearby water bodies. Therefore, preventing erosion is crucial to maintain the stability and health of the surrounding environment.Rate this question:
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- 10.
Runoff may be disposed of onto ________________ vegetation.
- A.
Well-established
- B.
Well-maintained
- C.
Slow-growing
- D.
Dry
Correct Answer
A. Well-establishedExplanation
Runoff may be disposed of onto well-established vegetation because well-established vegetation has strong and deep root systems that can absorb and retain water effectively. This helps to prevent erosion and allows the water to slowly infiltrate into the soil, replenishing groundwater supplies. Additionally, well-established vegetation provides shade and reduces the impact of rainfall, further reducing runoff. Overall, well-established vegetation is a sustainable and environmentally-friendly option for disposing of runoff.Rate this question:
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- 11.
____________ ________________ structures are used to carry runoff from one level to another.
- A.
Silt fencing
- B.
Check dams
- C.
Grade stabilization
- D.
Sedimentation control
Correct Answer
C. Grade stabilizationExplanation
Grade stabilization structures are used to carry runoff from one level to another. These structures help to control erosion and prevent the loss of soil by redirecting the flow of water and reducing its velocity. By stabilizing the grade, these structures prevent the formation of gullies and channels, and instead promote the spread of water evenly across the landscape. This helps to minimize erosion and sedimentation, protecting the surrounding environment and infrastructure.Rate this question:
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- 12.
____________ occurs when water erodes small channels under or along the side of a water conveyance structure.
- A.
Piping
- B.
Rilling
- C.
Sheeting
- D.
Roughening
Correct Answer
A. PipingExplanation
Piping occurs when water erodes small channels under or along the side of a water conveyance structure. This erosion process weakens the structure's foundation and can eventually lead to failure or collapse. Piping is a common issue in dams, levees, and other water infrastructure systems. It is important to monitor and address piping to ensure the stability and integrity of these structures.Rate this question:
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- 13.
______________ _____________ is/are often used in roadside ditches to reduce the velocity of water.
- A.
Grade compaction
- B.
Surface roughening
- C.
Stabilization structures
- D.
Check dams
Correct Answer
D. Check damsExplanation
Check dams are often used in roadside ditches to reduce the velocity of water. Check dams are small structures built across a channel or ditch to slow down the flow of water and prevent erosion. They consist of a series of low barriers or walls that create a series of small pools, allowing water to collect and gradually release downstream. This helps to reduce the velocity of water, prevent erosion, and promote sediment deposition, which can be beneficial for roadside drainage and overall water management.Rate this question:
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- 14.
The center of the check dam should always be _________________ than the outside edges to prevent scouring around the structure.
- A.
9 inches lower
- B.
1 ft lower
- C.
3 inches lower
- D.
3 inches higher
Correct Answer
A. 9 inches lowerExplanation
To prevent scouring around the structure, the center of the check dam should always be lower than the outside edges. By having the center 9 inches lower, it creates a slope that allows water to flow smoothly without causing erosion or damage to the dam. This ensures the stability and effectiveness of the check dam in controlling water flow and preventing scouring.Rate this question:
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- 15.
The size of the stone used in check dams should be _____________ as slope and/or velocity increases.
- A.
Increased
- B.
Decreased
Correct Answer
A. IncreasedExplanation
As the slope and/or velocity increases, the force of the water flowing in the river also increases. To effectively slow down the flow and prevent erosion, larger stones are required in the construction of check dams. Larger stones have more mass and can withstand the higher force of the water, providing stability and preventing the erosion of the dam structure. Therefore, the size of the stone used in check dams should be increased as slope and/or velocity increases.Rate this question:
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- 16.
When anticipated channel velocities are too great to establish grass, one may have to use erosion control ___________ or ___________ ____________ mats
- A.
Riprap or turf reinforcement
- B.
Blankets or turf reinforcement
- C.
Riprap or silt fencing
- D.
Concrete or rock gabions
Correct Answer
B. Blankets or turf reinforcementExplanation
When anticipated channel velocities are too great to establish grass, one may have to use erosion control blankets or turf reinforcement mats. These materials are used to prevent erosion by providing a protective layer over the soil. Erosion control blankets are made of biodegradable materials and help to stabilize the soil and promote vegetation growth. Turf reinforcement mats, on the other hand, are made of synthetic materials and are designed to provide immediate erosion protection while allowing vegetation to establish and grow. Both blankets and turf reinforcement mats are effective in controlling erosion in areas with high channel velocities where grass cannot be established.Rate this question:
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- 17.
For extremely high velocities, it may be necessary to line the whole channel with __________, _____________, or ______________.
- A.
Riprap, rock gabions, or concrete
- B.
Blankets, turf or mats
- C.
Rocks, grass or sticks
Correct Answer
A. Riprap, rock gabions, or concreteExplanation
For extremely high velocities, it may be necessary to line the whole channel with riprap, rock gabions, or concrete. This is because these materials are able to withstand the force of the high velocity water and prevent erosion. Riprap refers to a layer of large rocks or stones placed along the channel to absorb the energy of the water. Rock gabions are wire mesh containers filled with rocks, which provide stability and erosion control. Concrete is a durable material that can be used to line the channel and protect it from erosion caused by high velocity water.Rate this question:
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- 18.
The most effective and least expensive way to prevent wind erosion is to keep the area covered with _________________ or with securely anchored ___________.
- A.
Blankets, turf mats
- B.
Vegetation, mulch
- C.
Silt fencing, riprap
Correct Answer
B. Vegetation, mulchExplanation
The most effective and least expensive way to prevent wind erosion is to keep the area covered with vegetation, such as grass or plants, and with mulch. Vegetation helps to anchor the soil and prevent it from being blown away by wind, while mulch acts as a protective layer that reduces the impact of wind and helps to retain moisture in the soil. Together, vegetation and mulch create a barrier that minimizes the effects of wind erosion on the area.Rate this question:
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- 19.
Other methods used to control wind erosion include:
- A.
Keeping the soil moist
- B.
Spraying chemical binders on the soil surface
- C.
Covering area with erosion control blankets
- D.
Planting fast growing grass
- E.
Placing snow fence perpendicular to the prevailing wind direction
Correct Answer(s)
A. Keeping the soil moist
B. Spraying chemical binders on the soil surface
E. Placing snow fence perpendicular to the prevailing wind directionExplanation
The correct answer includes three methods that can be used to control wind erosion. Keeping the soil moist helps to prevent it from becoming loose and easily carried away by the wind. Spraying chemical binders on the soil surface helps to bind the soil particles together, making them less susceptible to erosion. Placing a snow fence perpendicular to the prevailing wind direction creates a barrier that slows down the wind and reduces its erosive force. These methods are effective in controlling wind erosion and are commonly used in areas prone to this type of erosion.Rate this question:
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- 20.
To be effective, all control measures must be periodically ___________, _____________, and/or replaced when necessary.
- A.
Inspected, maintained
- B.
Surveyed, reevaluated
- C.
Inspected, stablized
Correct Answer
A. Inspected, maintainedExplanation
To ensure their effectiveness, control measures need to be regularly checked and assessed for any issues or deficiencies. This involves conducting inspections to identify any problems or faults and then taking appropriate actions to address them. Additionally, the control measures must be properly maintained to keep them in good working condition and prevent any deterioration or malfunction. By regularly inspecting and maintaining the control measures, any necessary repairs or replacements can be carried out promptly, ensuring their continued effectiveness in managing the desired control objectives.Rate this question:
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Current Version
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Mar 21, 2023Quiz Edited by
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Jun 22, 2009Quiz Created by
Dcrowe
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