Environmental Matters in the Commonwealth of Kentucky

“Storm water” means water that originates during precipitation events.   It may also be used to mean the water that originates with snowmelt or runoff water from overwatering that enters a storm water system.  Storm water that does not soak down into the ground is called “surface water runoff.”  Surface water runoff either flows into surface waterways (such as ditches, creeks, streams, rivers, lakes, or coastal waters) or is channeled into storm sewers.   Storm water is a public concern for two primary reasons: one is related to the sheer volume and timing of runoff water which may cause flash floods or wet basements.  The second reason is related to raw sewage and other pollution released from combined sewer systems during an overflow event.  A combined sewer system is a wastewater collection system that is specifically designed to collect and convey sanitary wastewater (domestic sewage from homes as well as industrial and commercial wastewater) and storm water through a single pipe.  Overflow events are caused by too much water entering the sewer system.  During such events a combined sewer system is designed to release water through overflow structures to protect the sewer system from damage.  It is a good way to relieve pressure in an overflow condition.  Unfortunately, water released from a combined sewer system normally contains raw sewage that contains human pathogens, solids, toxic pollutants, and debris.  Thus, overflows from combined sewer systems are a significant threat to human health, environment, and the flora and fauna of the receiving waterway.  U.S. EPA estimates that about 850 billion gallons of untreated wastewater and storm water are released through combined sewer systems each year.