What is a TMDL? The Oregon Department of Environmental Quality (DEQ) sets the The Total Maximum Daily Load of pollutants that can enter the Willamette River from local streams. Newberg is part of a watershed that has 5 different streams. https://www.oregon.gov/deq/wq/tmdls/Pages/default.aspx
Our TMDL Program Covers pollutants that enter streams as runoff from driveways, streets, roofs, lawns, and fields. Businesses are already familiar with limits for "end-of-pipe" or "point source" discharge and work with the City Pretreatment Program.
Why is this important? Whenever people build towns, cultivate fields, or change wooded areas it impacts the rivers and streams. Developed areas have more sediment, oil, litter, feces, nitrogen, phosphorus, and other chemicals that runoff to streams. This results in banks eroding, stream bottoms change into muck, invasive species and algae increases. This all affects aquatic life negatively and can even destroy it. The TMDL helps to control the pollutants entering the Willamette River from our streams.
In 2006, DEQ required the City to reduce the temperature, bacteria, and mercury entering the Willamette River. This included six specific areas including public education, erosion control, infrastructure maintenance, and stormwater management. In 2021 more stringent requirements were issued for mercury in the Willamette River Basin (see weblink below). A progress report, available for download below, is sent to DEQ every year. Every 5 years, the City program is updated. A summary previous 2 program cycles is available below along with the current 5-Year Plan 2018-2022.
