What is a TMDL?
A TMDL, or total maximum daily load calculation is an important tool in maintaining the water quality standards set for water bodies by states, territories, and tribes. Water quality standards identify uses for water bodies, including drinking water supply, contact recreation (swimming), and support for aquatic life (fishing), and then lay out the scientific criteria to support those uses. The federal Clean Water Act, section 303, establishes both the TMDL program and the water quality standards.
A TMDL is a calculation of the maximum amount of a pollutant that a body of water can receive and still meet water quality standards. A TMDL also divides up this maximum pollutant amount among the pollutant's sources including point and nonpoint sources of pollution. The TMDL calculation must include a margin of safety to ensure that the body of water can be used for the purposes the State or other entities have designated through its water quality standards. The TMDL calculation must also account for seasonal variation in water quality.
TMDLs and the Red River in the FM Area
The Red River is the major drinking water supply for the Fargo-Moorhead (FM) area and is also important for recreation and for aquatic life. As shown on the table, TMDLs are under development for four segments of the Red River in the FM area. These TMDLs address issues related to turbidity, ammonia, fecal coliform bacteria, and organic enrichment/low dissolved oxygen. The segments were identified jointly by the Minnesota Pollution Control Agency (MPCA) and the North Dakota Department of Health (NDDH) and these state agencies are cooperating with other groups in the region, including the municipalities of Fargo and Moorhead and the Red River Basin Commission, to develop the TMDLs. Click here to learn more about Water Quality Standards and the Red River.
Click here to view and graph water quality data for the TMDL sites.
| TMDL Reach1 | FM River Monitoring Sites2 | Description3 | Turbidity | Ammonia | F. Coli4 | Organic enrichment/low dissolved oxygen5 |
| 1 | R2 | Mouth of the Wild Rice River (RM 470.2) to Dam A (RM 448.9) | X | -- | X | -- |
| 2 | R3 | Dam A (RM 448.9) to 12th Avenue North Bridge (RM 449.3) | -- | -- | X | -- |
| 3 | R4, R5, R6 | 12th Avenue North Bridge (RM 449.3) to mouth of the Sheyenne River (RM 431) | -- | X | X | X |
| 4 | Mouth of the Sheyenne River (RM 431) to mouth of the Buffalo River (RM 417.1) | -- | X | X | X |
1 Informal FM River designation for the Red River TMDL segments; 2 FM River monitoring sites for the Red River that occur in the TMDL segment 3 Description of the TMDL segment; 4 Turbidity = area with potential for water with high turbidity levels; Ammonia = area with potential for water with high ammonia levels; area with potential for water with high levels of pathogens determined by Fecal Coliform bacteria measurement; 5 area with potential for water characterized by organic enrichment and low levels of dissolved oxygen