Contents

1. Fieldsketching

2. List of possible hypothesis

3. Discharge

4. Hydraulic Radius

5. Valley Transect

6. Sinuosity

7. Grain size of bedload Draw a field sketch using this grid River Discharge

Task 1: Using a measuring tape find the width of the river in metres.

Width ____ metres

Task 2 Stretch a measuring tape or rope across the river. Using a metre stick measure the depth of the river at half metre intervals across the river. Measure in metres so 14cms is recorded as .14M

M M M M

Depth Metres Task 3 Work out the average depth. 1 Total depths ÷ Number of depths = Average Depth

2 M ÷ = M

3

4 Task 4 Work out the crossectional area. Width x Average depth 5 2 M X M = M Total Task 5 Time how long it takes three oranges to travel 10 metres along the river as follows: Measure out 10 metres along the river bank and mark where the 10 metres begins and ends. People take up positions at the beginning (A) and end (B) of the ten metres section. The first orange is thrown in by (C) and when it passes (A) she calls out ‘Go!’. Then (D) starts the stop watch. When the orange passes (B) he calls out ‘Stop!’. Then (D) stops the watch and calls out the number of seconds to (E) who records it. This is repeated for the other oranges.

D Stop!! E Go!

B C 10 A Metres

Seconds

Seconds

Seconds

Time Task 6 Work out the average number of seconds an 1st Orange orange takes to travel ten metres. 2nd Orange Total Number of seconds ÷ 3

rd 3 Orange ÷ 3 = seconds Total Hydraulic Radius

The hydraulic radius is a measure of the efficiency of a river channel. It is calculated by comparing the wetted perimeter with the cross-sectional area of the channel. The formula is as follows: Hydraulic Radius = Cross-sectional area ÷ Wetted perimeter

The larger the hydraulic radius the more efficient the stream.

Wetted Perimeter

B A A

Task 1 Calculate the cross-sectional area of the channel. (See discharge work sheet.) Task 2 Carefully lay a chain down along the wetted perimeter. Begin at the surface of the water at A and continue along the submerged banks and bed of the river till you reach the surface of the water at B. Task 3 Mark the chain at B Task 3 Remove the chain from the river and carefully lay it out straight on the ground and Task 4 Measure the length of chain A - B with a measuring tape.

Wetted Perimeter Metres Valley Transect

Task 1 Observe the valley sides and identify the points at which the slope changes. Task 2 Draw a sketch of the valley sides showing the changes in slope.

Slope Sketch

The break of slope points can be marked in the field by ranging poles or people of the same height Left Bank Right Bank

G

B C F E D A

Task 3 Two people position themselves at point A to measure the foresight. Task 4 Two other people position themselves at B to measure the backsight. Task 4 Using a clinometer one person at A sights a person’s eyes at B along the straight edge of the clinometer. When the plumb line comes to rest the slope is read off the clinometer by the other person. This is the foresight. The slope is recorded. Task 5 Then a person at B measures the slope back to A. This is known as the backsight. It is measured and recorded as above. Task 6 The distance between A and B is measured with a tape measure. This is also recorded. Task 7 The same measurements are taken for each of the other sections of slope.

Slope Record Sheet

Slope Foresight Backsight Average Distance Section A-B

B-C

D-E

F-G

G-H Sinuosity

Task 1 Identify the points where the curve on the river changes direction . These points are shown as A and B in the diagram below.

A B

Task 2 Draw a sketch of the river curve in the box below and mark the points where the river changes direction. Task 3 Pace out the straight line distance between A and B and record it. Task 4 Pace out the curved distance between A and B. The curved distance is the distance along the river bank.

Sketch Map of the River

Straight Distance Paces

Curved Distance Paces Grain Size of Bedload

Task 1 Wade into the river and throw the quadrat onto the bed. Gather up the grains which touch the corners of the quadrat and take them to the bank. Task 2 Measure the long axis, the short axis and the medium axis of the grains in the pebbleometer. Return the grains to the river. If the quadrat’s corners touch a large boulder measure the axes of the boulder where it lies with a metre stick. Task 3 Record the measurements and return the grains to the river bed. Task 4 Repeat the process until you have measured at least 30 grains of the load.

Grain Long Short Medium Grain Long Short Medium Axis Axis Axis Axis Axis Axis Grain Long Short Medium Grain Long Short Medium Axis Axis Axis Axis Axis Axis 1 16 1 16 2 17 2 17 3 18 3 18 4 19 4 19 5 20 5 20 6 21 6 21 7 22 7 22 8 23 8 23 9 24 10 25 9 24 11 26 10 25 12 27 11 26 13 28 12 27 14 29 15 30 13 28 Total 14 29 15 30

Task 5 Get the average long axis of the bedload.

Total of long axes CMS ÷ Number of grains

Average long axis of bedload =