What is sediment transport in rivers primarily concerned with?
A Rainfall patterns
B River depth
C Movement of particles
D Water quality
Sediment transport in rivers involves the movement of particles such as sand, silt, and clay by water flow. It is important for river channel formation, floodplain deposition, and water quality management.
What is the primary purpose of river training works?
A Harvest water
B Control river flow
C Prevent soil erosion
D Increase water flow
River training works aim to control the flow of water in rivers by constructing structures such as levees, dikes, and embankments, preventing flooding, erosion, and property damage in vulnerable areas.
Which of the following is a key aspect of watershed management?
A Reducing water use
B Enhancing soil erosion
C Increasing evaporation
D Conserving water resources
Watershed management focuses on conserving water resources within a watershed area through sustainable land use, protecting ecosystems, and minimizing negative impacts like erosion and pollution.
Which factor affects the rate of sediment transport in rivers?
A Wind speed
B River discharge
C Water temperature
D Atmospheric pressure
The rate of sediment transport is largely influenced by river discharge, as higher flow velocities can move larger and heavier particles downstream, contributing to erosion and sediment deposition.
Which structure is used to control sediment movement in rivers?
A Weir
B Lock
C Dam
D Levee
A weir is a structure built across a river to control water flow and sediment movement. It can regulate water levels, prevent sediment accumulation, and protect riverbanks from erosion.
What is the role of vegetation in watershed management?
A Increase water runoff
B Prevent soil erosion
C Increase evaporation
D Decrease water quality
Vegetation plays a critical role in watershed management by preventing soil erosion, stabilizing riverbanks, and improving water quality through the filtration of pollutants in runoff.
What is the main objective of river training works?
A Manage sedimentation
B Increase water depth
C Promote evaporation
D Direct water flow
River training works aim to direct the flow of water to prevent flooding, reduce erosion, and protect land and infrastructure. This is achieved by constructing barriers and channels to control water movement.
Which of these factors influences sediment deposition in rivers?
A Humidity
B Solar radiation
C Flow velocity
D Temperature
Sediment deposition occurs when river flow velocity decreases. As the water slows down, it loses the energy to carry sediments, causing particles to settle along the riverbed or floodplain.
How does human activity impact sediment transport in rivers?
A Increases runoff
B Decreases river flow
C Increases sediment deposition
D Decreases evaporation
Human activities, such as deforestation and urbanization, can increase runoff by reducing soil infiltration, which accelerates sediment transport into rivers and may lead to increased sedimentation downstream.
What is the impact of excessive sediment in rivers?
A Decreased sedimentation
B Increased river depth
C Blocked water flow
D Water quality improvement
Excessive sediment in rivers can block water flow, damage ecosystems, increase water turbidity, and affect water quality. It may also impair infrastructure like dams, weirs, and irrigation systems.
What is the role of river training works in flood management?
A Increase precipitation
B Divert excess water
C Regulate sediment flow
D Store floodwater
River training works help divert excess water during floods by controlling river flow with structures like levees and floodwalls, reducing the risk of damage to nearby areas and ensuring safe water passage.
What is a common method used for managing sediment in rivers?
A Vegetation planting
B Floodplain restoration
C Dam construction
D River dredging
River dredging is a method used to remove sediment that accumulates in riverbeds and channels. This is done to improve navigation, water flow, and reduce flood risks caused by sedimentation.
What does the term “sediment transport capacity” refer to in rivers?
A Ability to prevent erosion
B Ability to hold water
C Ability to carry sediments
D Ability to evaporate water
Sediment transport capacity refers to a river’s ability to carry sediment particles of various sizes. This depends on flow velocity, water depth, and the type of sediment present in the river.
Which of these activities is part of river training works?
A Floodplain agriculture
B Riverbank stabilization
C Soil conservation
D Groundwater recharge
Riverbank stabilization is an essential part of river training works. It involves reinforcing banks to prevent erosion, which is vital for protecting infrastructure and maintaining river flow capacity.
What is one of the main goals of sediment management in rivers?
A Maintain ecosystem balance
B Control flooding
C Prevent soil erosion
D Improve water clarity
The main goal of sediment management is to maintain the balance of the river ecosystem. Managing sediment levels ensures that aquatic habitats are protected and that rivers continue to function effectively.