There are two systems of drainage, the Sanitary Sewer or Wastewater System and the Storm Drain System.
The Wastewater Sewage takes household wastewater (such as water waste from sinks, toilets, washers, etc.) and carries it through a home's plumbing system and into an underground sewer pipe.
Storm Drain System
On the other hand, the Storm Drain System carries discharge off city streets and routes it into curbside catch basins. From there, it also enters underground, but in a completely separate system.
Illegal dumping in the streets and in the storm drain system is one of the largest contributors to water pollution in the country. The exposed open flood control channels and tunnels are often easy targets for illegal dumping and convenient trash disposal. Soiled diapers, shopping carts, yard waste and used oil containers are just some of the many items tossed into the channels from above.
When it rains, water runoff will carry these items through the storm drain system and eventually make its way into Decker Lake.