TMDL prioritization

Development

For a Water Quality Limited stream segment that requires a Total Maximum Daily Load (TMDL), the pollutant sources and allocate allowable loads to the contributing sources, both point and nonpoint, must be qualified so water quality standards can be attained for that segment. TMDL development is a rational method for weighing the competing pollution interests and developing an integrated pollution reduction strategy for point and nonpoint sources.

TMDL development includes these five basic steps:

1. Select the pollutant to consider.

2. Estimate the water body assimilative capacity.

3. Identify the contribution of that pollutant from all significant sources.

4. Analyze information to determine the total allowable pollutant load.

5. Allocate (with a margin of safety) the allowable pollution among the sources so water quality standards can be achieved.

The complexity of the TMDL development is determined by water body, the sources and the pollutant being considered. While not all segments and TMDLs require complex computer modeling, some do.

Implementation of control information

Implementation of the Total Maximum Daily Load (TMDL) is the final step. It requires participation from all the stakeholders, as TMDLs are not self-implementing.

The waste load allocation portion of the TMDL can be implemented through effluent limits in discharge permits. In the case of non-point sources, voluntary controls or locally enacted controls are necessary to implement the load allocations.

We rely on authority already granted by the federal Clean Water Act to implement TMDLs.

Public notices (Information, drafted notices)

Upcoming Public Stakeholder Meetings

• January 23, 2025, 10 a.m. to Noon
  Public Webinar: Introduction to TMDLs, Zoom registration link
• February 5, 2025, 10 a.m. to Noon
  Bear Creek Reservoir TMDL Remote Stakeholder Meeting, Zoom registration link
• February 19, 2025, 10 a.m. to 11 a.m.
  Deweese Reservoir TMDL Remote Stakeholder Meeting, Zoom registration link
• February 27, 2025, 10 a.m. to Noon 
  Fountain Creek & Monument Creek TMDL Remote Stakeholder Meeting, Zoom registration link
• May 1, 2025 10 a.m. to Noon
  Cache la Poudre River Basin TMDL Remote Stakeholder Meeting, Zoom registration link
• May 22, 2025 10 a.m. to Noon
  Lower Bear Creek TMDL Remote Stakeholder Meeting, Zoom registration link

TMDL Documents

• Arkansas River basin 
• Gunnison and Lower Dolores River basins
• Lower Colorado River basin
• Rio Grande River basin
• San Juan and Dolores River basins
• South Platte River basin
• Upper Colorado River basin