TMDL Check List

Basic Components for Approval and Comments

  1. Plan is developed to meet State Water Quality Standards.

    For each TMDL, a description of the applicable standards for the waterbody of concern should be provided.  There  should be reasonable assurance that these standards will be attained as a result of implementing the TMDL.  If uncertainty exists, a "phased" TMDL approach may be used, relying on post-implementation monitoring to determine the success of meeting water quality goals.  Water quality standards may include numeric, narrative, use classification, and antidegradation components.

  2. Plan has quantified goals, targets or endpoints.

    Although a numeric water quality standard often serves as the target (e.g. 5mg/L dissolved oxygen, 200 #/100 ml fecal coliform), seldom do state water quality standards have numeric nutrient and sediment standards that are useable for nonpoint source issues.  Instead, an endpoint or endpoints have to be established that address the site-specific nature of the problem.  These endpoints are established as a means to judge success of the control measures in restoring water uses.  There are a number of different endpoints the Region have approved as part of the TMDL review process.  DEQ can provide more information on different types of targets/endpoints that have been used as part of TMDLs in the region.

  3. Plan has quantified pollutant reduction targets.

    TMDLs need not be expressed in pounds per day or concentration when alternative means of expression are better suited to the waterbody problem.  Based on EPA's TMDL regulation, TMDLs can be expressed as mass per unit of time, toxicity, or other appropriate measure.  "Other appropriate measure" could include an estimate of % reduction in sediment or nutrients needed to achieve water quality standards.  In developing a TMDL, it is most helpful to first visualize the solutions that will be used to address the water quality problem, and then adapt the TMDL to fit the solutions.  For example, if the water quality issue is excessive sedimentation from upland conditions, then the TMDL should relate to the decrease in amount of erosion from uplands.  If the issue is sedimentation related to channel conditions, then the TMDL should somehow relate to the decrease in the amount of bank erosion or perhaps the increase in stream stability.  DEQ can provide examples of different types of TMDLs that have been used in the region.

  4. All significant sources of a pollutant are considered.

    The term "pollutant" is used broadly to include traditional pollutants such as metals, nutrients, BOD, and fecal coliform, but such things as sedimentation, elevated stream temperature due to poor riparian conditions, and poor flow regimes are also included.  All sources or causes of the stressor must be identified or accounted for in some manner.  This accounting can lump several sources of unknown origin together.  The TMDL need only address the control of a subset of these sources as long as the water quality standards are expected to be met as a result of controlling those sources.  for nonpoint source TMDLs, this often means that priority areas in the watershed can be identified and targeted for controls.

  5. Plan uses an appropriate level of technical analysis.

    The level of complexity of nonpoint source TMDLs can vary from site-to-site.  The ultimate goal of the Clean Water Act is improvement and protection of water quality.  The "correct" level of analysis is that level that will result in meeting this goal.  We feel it is also important to tailor the level of analysis such that the stakeholders proceed with implementation of BMPs, resulting in attainment of water quality goals.  DEQ and EPA will approve a range of approaches for TMDL development, some relying on best professional judgment and yet others relying on more sophisticated modeling.

  6. Plan considers seasonality and incorporates a margin of safety.

    The Clean Water Act requires each TMDL to be established with a margin of safety.  A margin of safety can be either explicit or implicit in the analysis or assessment.  For nonpoint sources, there is often high variability in the data as well as uncertainty in BMP effectiveness.  Applying an explicit margin or safety (for example - some specific number of BMPs that will assure water quality standards are met) may be difficult under these circumstances.  Because of the possible uncertainty involved in nonpoint source TMDLs, the margin of safety is addressed by requiring post-implementation monitoring to assure the control practices are working and the water quality endpoints are being met.

  7. Responsibilities for implementation are assigned.

    In a geographic sense, TMDLs may be allocated by individual discharger, by tributary watershed, by source, or land use category, by land parcel, or other appropriate scale or partitioning method.  Allocations for nonpoint sources are often best professional estimates whereas waste load allocations for point sources are often based on a more detailed analysis.  Further, the allocation of nonpoint source TMDLs can be an allocation of actual loads or it may be an allocation of responsibilities.  Allocation of responsibilities can take the form of identifying what BMPs will be applied and where they will be applied in the watershed for the purpose of meeting water quality goals.  It should also be noted that approvals of nonpoint source TMDLs by DEQ and EPA have acknowledged the reliance on voluntary control programs.

  8. Appropriate level of public involvement.

    States usually meet this requirement by publishing a public notice of the TMDL, asking for comments.  In the case of many nonpoint source projects, there is involvement from  range of stakeholders from the beginning through the end of the project, so a public notice may contribute little to informing stakeholders and explaining what will be done.  The fundamental requirement for public participation is that all stakeholders have an opportunity to be part of the process.