TMDL stands for "Total Maximum Daily Load" and refers to the maximum amount of pollutant a body of water can receive while meeting water quality standards. As the Designated Management Agency (DMA), the City of Amity is required by DEQ to implement a TMDL plan that outlines management goals, projects, partners, priorities, schedule, and findings with tracking, monitoring, and reevaluation processes.
As a DMA, the City of Amity has authority over the sources of pollution entering the Yamhill River which contributes to water quality issues in the Willamette River. Waterways in Amity, including the Salt Creek and Ash Swale are contributors to the problem. The City must implement Best Management Practices (BMPs) to control pollution in these sources according to the Department of Environmental Quality.
DEQ requires many local governments to develop and implement a TMDL Implementation Plan. According to the federal Clean Water Act, Oregon is required to establish Total Maximum Daily Loads for streams segments which do not meet water quality standards. The TMDL identifies the level of pollutants that a water body can absorb and still meet water quality standards.
TMDLs take into account pollution from all sources, including residential areas, businesses, industry, and construction sites.
In response to DEQ, the City has developed a TMDL Implementation Plan according to DEQ regulations. This document sets out specific BMPs that will address contributions of mercury to local waterways. Mercury is a toxic heavy metal. Bioaccumulation of mercury in fish tissue can lead to fish consumption limits due to health hazards associated with consuming fish. Waterways can become contaminated when soil that naturally contains mercury are eroded.
The City of Amity's TMDL Implementation Plan with the Status Reports for 2023 are linked below.