# River Measurements

Measuring river flow and water levels involves several methods and instruments. Here are some key points.....

## 1. WIDTH

Equipment: Tape measure  and  Ranging poles.

Procedure: Stretch the tape measure over the surface of water from one edge of the channel(the area between the banks where the stream flows) to the other edge.

## 2. River Depth

Equipments:   Ruler(Metric rule),  Tape measure/Rope,  Ranging poles.

Procedure: Stretch the tape measure/rope across the channel

Mark  equal intervals along a tape measure e.g. Every two meter.

Use the metric rule to measure the depth of water of each interval, Rest ruler on river bed and  take reading at surface.

Stretch measuring tape / rope across channel / from one bank to the other

Record measurement of width (in metres)

Rest rule / ruler / ranging pole on river bed / lower rock on string to river bed

Make sure ruler is upright / vertical / make sure string is taut

Measure depth at regular intervals across channel (every metre)

Read off the scale where water level reaches / where ruler is wet

Record measurement of depth (in cm / metres)

## 3. Velocity.(using float)

Procedure:

• Measure length of river (10 m) , divide into sections put ranging poles to mark out section and  set up start and finishing points.
• Put orange / float / floating object into river
• Time float moving over distance.
• Repeat and calculate average.
• Calculate velocity by dividing distance by time.

## Using a velocity meter (Flow meter)

Procedure:

• Put velocity meter into river / into the water.
• Propeller must be facing upstream / nothing in front of propeller.
• Read / look at digital / velocity reading / display / speed is shown on display.
• Take several readings over time and calculate average.

## 4. Wetted perimeter

The wetted perimeter is the distance measured on banks  and stream flows that the water in the channel is in contact  with.

Procedure:

A long piece of chain is laid across the bed of a stream , it bends to go up and down and over the rocks and pebbles on the stream bed.

You need to check that it is resting on the bed of the channel for the accuracy of measurements.

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