Table of Contents
What are the sections of a river?
There are three main sections along the long profile of a river. These are the upper, middle and lower course. Each has its own channel cross-profile features.
How do you take a cross-section of a river?
Using a tape measure, hold one end at the point where the water meets the bank one side of the channel. Ensure the tape is not twisted pull the tape measure across the river and measure to the point where the water meets the bank directly opposite. Plan view and cross-section of a stream to show width measurements.
What is cross-section geography?
Definition: Cross-sections are represented on a map by a line which will often be labelled A at one end and B at the other. If you were to slice through the map along this line, and look back, you would be able to see what is happening underneath the ground.
Why does the cross-section of a river change downstream?
As the river flows downstream it is joined by tributaries, increasing the volume of water, velocity and therefore its erosive power. This enables it to cut a deeper channel as it flows downstream. Downstream, the channel becomes wider as the gradient becomes more gentle leading to less vertical erosion.
What are the 3 main sections of a river?
There are three sections in a river they are called: The upper Course, The Middle Course and The Lower Course. A river transports material through: Deposition occurs when the river starts losing energy.
What are the three parts of a river called?
The upper course, middle course, and lower course are the three parts of the river. The source of a river can be found on the upper course.
How is cross section measured?
Cross-Sectional Area of a Rectangular Solid The volume of any rectangular solid, including a cube, is the area of its base (length times width) multiplied by its height: V = l × w × h. Therefore, if a cross section is parallel to the top or bottom of the solid, the area of the cross-section is l × w.
How do you find the area of a cross section of a river?
Cross-sectional area (A in the formula) is the product of stream width multiplied by average water depth.
Why is cross-section important?
Cross-sections are important tools that aid in the interpretation and presentation of geological data, however; they provide only a two-dimensional picture and must be interpreted accordingly. They are most effectively used in conjunction with other illustrative techniques.
What is a cross-section profile?
A graphic representation of the sections that are in a linear work, on cutting the axis of the aforementioned work with vertical planes perpendicular to it and defining the trace in elevation.
What erosion makes a river wider?
Lateral erosion makes a river wider. This occurs mostly in the middle and lower stages of a river.
How do rivers change shape?
The process whereby water moves sediment from one location to another is called erosion. Much like their stream models, as a stream continues to flow, it carries more and more sediment away, changing the shape of the stream.
Why do you need a cross section of a river?
Producing a cross-section of a river channel is a basic river fieldwork skill. Whether you need to find the discharge or examine the profile of a feature such as a meander or riffle, it will be necessary to produce a cross-section of the river. The first stage is to measure the width and depth of the river.
How does the cross profile of a river change?
How and why does a valley cross-profile change downstream? How does it change? In the upper course, the valley cross-profile is narrow and steep-sided. The river takes up most of the valley floor. In the middle course, the valley becomes wider due to lateral erosion. By the lower course, the valley is almost flat, consisting of a wide flood plain.
How is the intersection of the cross sections used?
The intersection of the River layer and the Cross Sections layer is used to compute the River Station based on the distance from the most downstream point on the river reach line. This distance can be “overwritten” using the River Station Markers layer.
How to calculate the cross sectional area of a river?
Having drawn your cross-section by ‘joining the dots’ on your graph you have created a scale picture of a slice through the river. This diagram can be used to calculate the cross-sectional area or wetted perimeter of the river, which are needed to find discharge and channel efficiency.