Total Maximum Daily Load (TMDL) Monitoring Development and Implementation

Overview:

The TMDL process determines how much of a pollutant a water body can receive without violating the water quality standard. The DEQ Laboratory staff is involved in the process by developing sampling plans to characterize baseline water quality conditions. The Laboratory also gathers data once the TMDL plan has been implemented to help determine if water quality has improved. Objectives of the Program:

Objectives of the Program:

Intensive Watershed Assessments
Characterize sources and loads
Develop Conceptual and Mathematical Models
Establish Assimilative Capacity, Limiting Factors, Waste Load Allocations

Extent of Monitoring:

Depending on the TMDL data needs, some or all of the following data may be collected:

Hydrology: Flow, Time of Travel, Seasonal Variability, Groundwater Affects
Chemistry: Longitudinal Sampling Surveys, Synoptic Sampling Surveys, Source Studies
Temperature: Shading and Channel Characteristics, Temperature
Biological: Fish, Macro-invertebrates, Algae Sampling
May span several years with hundreds to thousands of samples

2007 study basins: Yamhill, Pudding, Coos, Tillamook, Johnson Creek(Portland), Alsea/Siuslaw, Coquille, Willow Creek(Heppner), Powder

2008 study basins: Yamhill, Tillamook, Yaquina, Alsea, Siuslaw, Salmon, Beaver Creek (Mid-coast), Coquille, Floras Crk, Hunter Crk, Pistol, Calapooya Creek, John Day, Middle Deschutes

How data are used:

Characterize baseline water quality conditions
Develop and Calibrate TMDL Models
Fill in existing data gaps
Set load limits for listed water quality parameters
Help determine source controls needed to meet load limits
For more TMDL information:
Search the 303(d) list for water quality status of Oregon waters