"Stormwater is rainwater or melted snow that runs off streets, lawns and other sites. When stormwater is absorbed into soil, it is filtered and ultimately replenishes aquifers or flows into streams and rivers.
In developed areas, impervious surfaces such as pavement and roofs prevent precipitation from naturally soaking into the ground. Instead, water runs rapidly into storm drains, sewer systems and drainage ditches and can cause:
- Downstream flooding
- Stream bank erosion
- Increased turbidity (muddiness created by stirred up sediment) from erosion
- Habitat destruction
- Combined storm and sanitary sewer system overflows
- Infrastructure damage
- Contaminated streams, rivers and coastal water"
(EPA)
This is what happens to stormwater in industrial areas which are predominantly covered with surfaces such as pavement or buildings made of impermeable stone, wood, and metal. When water runs across these surfaces it picks up residues like gas, tire debris, oil, paint and more which become water contaminants. This causes huge negative impacts on aquatic ecosystems in the ways mentioned above because stormwater is not treated, cleaned, or processed. Stormwater simply collects in storm drains and drainage ditches and flows into nearby creeks and rivers like Wade Creek and the Clackamas River.
The 1200-Z permit was created to make sure industrial operators developed pollution control and prevention plans to prevent these downstream effects which impact everyone.