Stormwater Flow Measurement
Stormwater Flow Measurement
What is Stormwater?
Stormwater is the run-off or pooling of rain, melting snow, or any precipitation types in between that cannot be absorbed quickly enough by the surface it falls on. Stormwater is usually caused by heavy rainfall or significant amounts of snow melting at once. Stormwater consists of the original water and any other elements, whether they are liquids or solids, that have dissolved into the water or are being carried by the water.
Common contaminants contained in stormwater include pesticides, chemicals, deicers, road salt, oil, grease, you get the picture about possible liquids that can be absorbed easily by running or pooling water. The contaminants can also be sediment that has been eroded by the hydraulic force of the moving water and has continued to be carried by the force of the flow.
Depending on the rate of rainfall/melt, the hydraulic force produced by the movement of water can also collect large objects into its stream of flow and continue to carry them along. A simple low volume flow example would be a tree branch that flows downhill into a stream. An extreme volume example is a flooded river with a car bobbing up and down in it as it goes on its merry way.
Depending on the situation, stormwater can be a harmless annoyance, or it can be dangerous, like when it kills people who think they can make it through that giant lake on the road or go over a bridge that has water running over it. The damage caused by stormwater can be minimal or catastrophic, like the flooding damage caused by hurricanes.
What is the Difference between Rain Water and Stormwater?
Stormwater is the excess water that was not absorbed into the soil or existing bodies of water and by virtue of gravity is on the move or is accumulating and pooling in places it normally doesn’t. Rainfall is one of the events that creates and causes stormwater, if it occurs in sufficient amounts to outpace local absorption capabilities. Simply put, rainwater causes stormwater, but not all rainwater becomes stormwater. Stormwater can also be formed by rapidly melting snow, but not all melted snow becomes stormwater.
What Does Stormwater Consist of?
Simply put, it consists of anything it took with it as it moved. The options are endless. Think about the stormwater from a flooded parking lot as an example. The stormwater running off or pooling up in the parking lot is likely to contain all sorts of lovely things like oil, grease, anti-freeze, wads of gum, and mushy paper napkins.
