Interactions
A variety of factors affect the flow of rivers. These factors include climate, vegetation cover, soil, rock structure or ground covering, shape and slope of landforms.
Atmopshere - Climate
Climate has a direct impact on the way a river flows. At times of heavy rainfall a river will have greater volume of flow (more water flowing). At times of hot weather evaporation of water increases. This reduces the volume of water (less water flowing).
Atmopshere - Climate
Climate has a direct impact on the way a river flows. At times of heavy rainfall a river will have greater volume of flow (more water flowing). At times of hot weather evaporation of water increases. This reduces the volume of water (less water flowing).
Biosphere - Vegetation
Vegetation absorbs water from soil to use in plant growth. Vegetation greatly reduces runoff. The less vegetation, the more abundant and rapid the runoff will be. A close plant cover will modify the violent affects of heavy rains. Vegetation growing in and on river channels may be regarded as a surface roughness which can slow the flow of the river (this is particularly important in times of flood).
Vegetation absorbs water from soil to use in plant growth. Vegetation greatly reduces runoff. The less vegetation, the more abundant and rapid the runoff will be. A close plant cover will modify the violent affects of heavy rains. Vegetation growing in and on river channels may be regarded as a surface roughness which can slow the flow of the river (this is particularly important in times of flood).
Lithosphere - Soil/Rock structure/Ground covering
The ground surface surrounding a river will affect how much water will enter the river as run-off and groundwater. Together with vegetation, the ground cover type influences the amount of water that will infiltrate or run-off. Some soils or rock structures are highly permeable (they absorb water) and have a large water-holding capacity, e.g. coarse-grained sandstones and porous limestones. These rocks and soils can even out the groundwater discharge even during dry seasons. Other ground surfaces such as cement pathways, driveways and tarred roads greatly increase the amount of run-off because no water is able to infiltrate. This increased run-off generally known as stormwater enters drains and is directed to nearby creeks and rivers.
The ground surface surrounding a river will affect how much water will enter the river as run-off and groundwater. Together with vegetation, the ground cover type influences the amount of water that will infiltrate or run-off. Some soils or rock structures are highly permeable (they absorb water) and have a large water-holding capacity, e.g. coarse-grained sandstones and porous limestones. These rocks and soils can even out the groundwater discharge even during dry seasons. Other ground surfaces such as cement pathways, driveways and tarred roads greatly increase the amount of run-off because no water is able to infiltrate. This increased run-off generally known as stormwater enters drains and is directed to nearby creeks and rivers.
Lithosphere - Landform shape and slope
Slope greatly affects the amount of run-off which will occur and thus how much water will enter a river. Generally the steeper the slope, the more run-off. Flat areas (especially where marshes and lakes occur) tend to accumulate water and slow down the flow of water.
Catchments which are bordered by or contain high, steep landforms are more likely to have greater volumes of water due to the occurrence of orographic rainfall (cool air travels across the land and warms up, it hits mountains and rises causing rainfall).
The size of the catchment can also influence the volume of water flow. Small drainage basins (catchments) show a great increase of flow after rainfall, while large catchments are more able to absorb the effects of precipitation.
Slope greatly affects the amount of run-off which will occur and thus how much water will enter a river. Generally the steeper the slope, the more run-off. Flat areas (especially where marshes and lakes occur) tend to accumulate water and slow down the flow of water.
Catchments which are bordered by or contain high, steep landforms are more likely to have greater volumes of water due to the occurrence of orographic rainfall (cool air travels across the land and warms up, it hits mountains and rises causing rainfall).
The size of the catchment can also influence the volume of water flow. Small drainage basins (catchments) show a great increase of flow after rainfall, while large catchments are more able to absorb the effects of precipitation.
True or false
- A flow of water in a river in a larger catchment will be affected more by rainfall than a river in a smaller catchment.
- An area with little or no vegetation is likely to have more run-off than an area with dense vegetation
- An impermeable ground cover will allow water to soak into the surface.
- A flow of water in a river in a larger catchment will be affected more by rainfall than a river in a smaller catchment.
- An area with little or no vegetation is likely to have more run-off than an area with dense vegetation
- An impermeable ground cover will allow water to soak into the surface.
