Measuring Flow of water

Cross section of a Water source

• The following image shows a cross section of a river stream

Measuring float

• Float methodFollowing method is explained in the slide given

next

Measuring flow

From figure in previous slideWe need to • Calculate the average depth of stream• Calculate the width of stream• A piece of wooden/cork material• Select a straighter area of stream/river/canal

Measuring flow

After calculating depth and width• Now float a small rubber piece on river• With stop watch measure time taken• This will be the length

Measuring Flow

• Now you know length,width and distance covered

• You know the time taken by floating rubber• Now use formula for volumeVolume = length x breadth x depthYou can find out how much cubic meter volume

water flows in one secondDetailed image shown in next slide

Measuring flow

• Please refer the following figurePoint A and point B in figure is lengthYou have widthYou have depthYou have time taken from point A to BUsing formula,volume can be calculated

• Distance travelled by object from point A to B will be the distance

• We have time• Distance/Time = surface velocity• Average velocity = surface velocity x 0.85Usually mean of surface velocity factor comes to

0.85

• Now you have average velocity

• Now calculate area of cross section

• Types of area1) Rectangular 2) Trapezoidal

Calculating surface areas

• Rectangular area