Friday, November 2, 2012

Do you know what is in your storm water?

     With a sizable area of the country sitting in storm water left behind by hurricane Sandy and a winter storm, I would like to again focus on storm water.  This week I would like to ask you:  Do you know what is in your storm water?  I would be willing to bet that a number of people who never thought about storm water before this week could now answer that question - at least to some extent.
     Storm water is water that has hit the ground through rainfall.  In a natural, not man altered environment, the bulk of this water will infiltrate into the ground, work its way through the soil and into the water table and may eventually emerge back on the surface having been cleaned by the soil as water in creeks, streams, ponds and ultimately the oceans.
     Man has interfered with this system through his building of structures and paving of roads, parking and walks.  As a result, we have more storm water to deal with when we have rain.  This storm water washes downhill instead of soaking into the soil.  When it does, it picks up a good deal of contaminates - both natural and man caused.
     Rain falls through the air near the earth and as it does, it collects gasses that can be dissolved in the water.  The primary gas that is picked up in the fall to earth is nitrogen.  This is an element that is greatly needed by plants.  In nature this is the primary way that nitrogen is disseminated into the soil.  When impervious areas are created, rain does not soak into the soil and is instead concentrated and allowed to run off into streams.  Nitrogen in concentrations cause algae in water areas like slow-moving streams and ponds to grow rapidly.  As it dies, it decomposes and the process of decomposition robs the water of dissolved oxygen.  This leads to the death of fish and other organisms that depend on that dissolved oxygen.
     A similar kind of die-off can occur when soil is allowed to flow off a site as erosion.  The soil left unprotected dissolves in water running downhill.  It clouds the water killing aquatic plants.  When the plants die off and decompose, they too use up the dissolved oxygen leaving none for the aquatic organisms that depend on it.
     Storm water also tends to pick up anything that will float in it and anything that will dissolve in it as it heads downhill.  That translates to picking up garbage that might be laying in the path of the water.  This also means that it picks up all kinds of waste that can be dissolved into the water.  Water flowing off farms and yards will pick up excess insecticides, herbicides, fungicides and fertilizers.  Water flowing off parking lots and streets will pick up fluids like motor oil that might leak out of cars.  It will also pick up whatever people might toss out onto the soil like paints, solvents and other chemicals.
     Water washing downhill will also pick up whatever pathogens might be left on the soil surface.  In a natural system, waste from the animals living in the area will be broken down and treated where it is deposited.  With the addition of pets and livestock to that natural system, excess pathogens are deposited.  Cats and dogs, along with livestock like cattle, pigs and poultry can provide huge increases in the bacteria and other pathogens that end up in the surface water if people are not careful to pick up and treat the waste from their animals.  After all, those animals would not naturally be concentrated in one area.
     It is important to remember what will end up in the storm water.  Everyone has to deal with that water at some point in the system.  We all need to work to keep that water clean and safe.

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