Traditionally, storm management is focused on collection of storm water through pipes and drainage transporting water runoff as quickly as possible to stream, creeks, rivers and sometimes sewer system. However, storm water management includes anytime water flows at facilities, on roads, off of properties into water systems. Erosion, debris, chemicals, sediment, salt and sand runoff are all part of managing water flows that must be filtered before entering sewers or other fresh water sources.
As described by the EPA, the process starts with storm water, rainwater and melted snow or general maintenance water use that runs off land, streets, lawns, and other urban hard surface environments. When storm water is absorbed into the ground, it is filtered and ultimately replenishes aquifers or flows into streams and rivers.
In developed areas, however, solid surfaces such as pavement and roofs prevent precipitation from naturally soaking into the ground. Instead, the water runs rapidly into storm drains, sewer systems, and drainage ditches picking up debris with it and can’t be absorbed as quickly.
The SWMP describes the stormwater control practices that will be implemented consistent with permit requirements to minimize the discharge of pollutants from the sewer system.