How do you measure the amount of water flowing down a small river.?
This is pretty easy. 1. Calculate area of a cross section of the river that you wish to measure. If it is shallow you can do this by taking a series of measurements across the river, say every 1m. 2. Determine flow rate. Easiest way to do this is to drop an orange in and time how long it takes to cover a measured distance, say 10 metres. 3. Knowing the cross-section (m2) and the flow rate ms-1, you can now easily calculate the volume of water passing down the river (cross section x flow rate) = volume per second. This will give you a figure in m3s-1. Easy peasy! By the way, the reason you use an orange is because they are only slightly bouyant and float with most of the orange below the surface. This means that the orange does not get blown around by the wind and so you will get a true representation of the water speed, not “wind assisted”.
