Table of Contents
- 1 How do you measure the cross section of a river?
- 2 What is the cross sectional area of a river?
- 3 How do you measure the width of a river without crossing it?
- 4 What is the cross profile of a river?
- 5 What is the cross-sectional area formula?
- 6 How do you measure the length of a river?
- 7 How does the cross-section of a river change downstream?
- 8 What is the method of measuring discharge from a river?
- 9 How to calculate the cross-sectional area of a river?
- 10 What is the method of surveying a river?
How do you measure the 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.
What is the cross sectional area of a river?
Use the metre ruler to record the depth of water from the river bed to the surface of the water. Start from one river bank and move at 30cm intervals across the river. Cross sectional area (CSA) (m 2) This is a simple calculation to measure the amount of water at each site (the cross sectional area of the water).
How do you measure cross profile?
Measuring the cross profile of a river River cross profiles show you a cross-section of a river’s channel and valley at certain points in the river’s course. How do you measure it? Multiply the average depth by the width of the river channel.
How do you measure the width of a river without crossing it?
- Locate two objects at points and on either side of the river such that perpendicular to the the river and is on your side of the river.
- Walk a certain distance away from point to a point such that and measure the distance.
- Now walk a certain distance away from point to a point such that and measure the distance.
What is the cross profile of a river?
The cross profile of a river shows how the width and depth of the river valley and channel change as you travel downstream. Near the source of a river there is more vertical erosion as the river flows downhill, using its energy to overcome friction (A).
How do you measure cross-sectional area?
Cross-sectional area is determined by squaring the radius and then multiplying by 3.14. For example, if a tree is measured as 10” DBH, the radius is 5”. Multiplying 5 by 5 equals 25, which when multiplied by 3.14 equals 78.5.
What is the cross-sectional area formula?
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 measure the length of a river?
The length of a stream is the distance measured along the stream channel from the source to a given point or to the outlet, a distance that may be measured on a map or from aerial photographs. On large-scale maps, it is measured along the geometrical axis, or the line of maximum depth.
How can we measure the length of a river?
We use a twine method to measure the length of a river. In the twine method, a twine is placed along the feature to be measured from one end to the other, carefully following all the curves and bends. The length of the twine is then measured in centimeters or inches using a ruler or linear scale.
How 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 is the method of measuring discharge from a river?
Method of Measuring River Discharge. The first step in making a conventional current-meter measurement of discharge is to select a measurement cross section of desirable qualities. If the stream can be waded, the hydrographer looks for a cross section of channel meeting as many of the following criteria as possible:
Why is velocity measured along a cross-section of a stream?
Velocity also varies within the cross-section of a stream, where stream banks are associated with greater friction, and hence slower moving water. Thus, it is necessary to take velocity measurements along a cross-section of a stream.
How to calculate the cross-sectional area of a river?
To manually calculate the cross-sectional area, use your raw data to draw the river cross-section (s) on graph paper. By maintaining the same scale for both the vertical and horizontal axes, calculation of the wetted perimeter and cross-sectional area is simplified.
What is the method of surveying a river?
Method of Surveying a River & Sounding. The survey of the shore line of a river is made by running a theodolite and tape traverse on a shore at a convenient distance form the edge of the water. If the river is narrow, a single theodolite and tape traverse is on one bank and both banks. Located by staid or plane table methods.