Mar 05 2012
Part 1 of 2:
By Joe Larson
It’s almost spring, and at Field we’re hoping that our abnormally mild weather will continue into March and April. However in the back of my mind, the part I try to ignore, I think there is a chance that winter is waiting to release it’s pent up fury on us in March.
Spring is the one time of year that a lot of homeowners think about percent of impervious surfaces, surface water runoff, and soil infiltration rates. Well maybe they don’t know that’s what they are thinking about, but they are wondering why their basement is flooded as they check on the sump pump. Wet basements aren’t the only problem that water runoff causes though.
The “dead zone” in the Gulf of Mexico the size of New Jersey, and decreased aquatic life and increased algae in our lakes and rivers are all a result of surface water runoff. In a modern city when it rains, around 40%-70% of the water that falls makes its way into the storm sewer systems by means of surface water runoff. The water carries with it a good deal of sediment and pollutants that become nutrients for algae in lake and rivers. The same fertilizer that helps your grass grow enables algae to grow. The algae uses sunlight to process the nutrients and when they die they fall to the lake or river bottom. The decomposition of these “algae blooms” takes a lot of oxygen out of the water and can in extreme cases, such as in the Gulf of Mexico, create an area that is hypoxic, or void of oxygen and thus cannot support marine life.
This is why there is a strong movement to filtrate and infiltrate storm water onsite. Filtrating the water removes sediments and can also remove contaminants from the water before it enters a lake or storm water drain. Infiltrating the water involves collecting the water into a depression and allowing it time to naturally seep into the ground. Rain gardens can accomplish both infiltration and filtration, and so too can permeable pavers which we will look at in the next blog.