Nutrient Pollution and Numeric Water Quality Standards - May 2007 Update Memo

Some states and territories have made notable progress in establishing numeric water quality standards for nitrogen and phosphorus pollution—most recently in connection with the Chesapeake Bay and Tennessee streams. However, overall progress has been uneven over the past nine years. Now is the time for EPA and its partners to take bold steps, relying on a combination of science, innovation, and collaboration.

Photo of waterbody surrounded by trees
Source: Michael B. Tate

May 25, 2007 Policy Memo:
Nutrient Pollution and Numeric Water Quality Standards


Why Action Is Needed

High nitrogen and phosphorus loadings, or nitrogen and phosphorus pollution, result in harmful algal blooms, reduced spawning grounds and nursery habitats, fish kills, oxygen-starved hypoxic or "dead" zones, and public health concerns related to impaired drinking water sources and increased exposure to toxic microorganism—such as cyanobacteria. Nutrient problems can exhibit themselves locally or much further downstream leading to degraded estuaries, lakes and reservoirs, and to hypoxic zones where fish and aquatic life can no longer survive.

Nutrient pollution is widespread. The most widely known examples of significant nitrogen and phosphorus impacts include the Gulf of Mexico and the Chesapeake Bay. For these two areas alone, there are 35 states that contribute the nitrogen and phosphorus loadings. There are also known impacts in over 80 estuaries/bays, and thousands of rivers, streams, and lakes. The significance of this impact has led EPA, states, and the public to come together to place an unprecedented priority on public partnerships, collaboration, better science, and improved tools to reduce nitrogen and phosphorus pollution.

Virtually every state and territory is impacted by nitrogen and phosphorus pollution-related degradation of our waterways. All but one state and two territories have Clean Water Act Section 303(d) listed impairments for nitrogen and phosphorus pollution. States have listed over 10,000 impairments related to nitrogen and phosphorus pollution. Fifteen states have more than 200 nitrogen and phosphorus pollution-related listings each. For these reasons, Regions have identified nitrogen and phosphorus pollution reduction as a priority for EPA.

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Why Numeric Criteria Are Important

Photo of a waterbody with algae near the shore
Source: Michael B. Tate

Water quality standards for nitrogen and phosphorus pollution will drive water quality assessments and watershed protection management. They will support improved development of nitrogen and phosphorus pollution Total Maximum Daily Loads (TMDLs). Perhaps most importantly, they will create state- and community-developed environmental baselines that allow us to manage more effectively, measure progress, and support broader partnerships based on nitrogen and phosphorus trading, Best Management Practices (BMPs), land stewardship, wetlands protection, voluntary collaboration, and urban storm water runoff control strategies. The progress of states and territories in setting numeric water quality standards for nitrogen and phosphorus pollution is extremely important to help address nitrogen and phosphorus pollution.

Water quality standards for nitrogen and phosphorus pollution will facilitate more effective and efficient program implementation. Notable progress has been made relying on site-specific application of narrative standards to develop nitrogen and phosphorus pollution TMDLs. But this can often be difficult, resource-intensive, and time-consuming. Adopting numeric standards, however, has a number of key advantages:

  • Easier and faster development of TMDLs
  • Quantitative targets to support trading programs
  • Easier to write protective NPDES permits
  • Increased effectiveness in evaluating success of nitrogen and phosphorus runoff minimization programs
  • Measurable, objective water quality baselines against which to measure environmental progress

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What Action Is Needed

Photo of a waterbody with algae near the shore
Source: Michael B. Tate

Today, EPA is encouraging all states, territories, and authorized tribes to accelerate their efforts and give priority to adopting numeric water quality standards for nitrogen and phosphorus pollution or numeric translators for narrative standards for all waters in states and territories that contribute nitrogen and phosphorus loadings to our waterways. Incremental progress can be an effective way to accelerate progress. If a state needs to implement numeric criteria for nitrogen and phosphorus pollution incrementally, EPA strongly recommends that states first adopt numeric water quality standards for priority waters—that is, waters at greatest risk of nitrogen and phosphorus pollution (such as those identified through the EPA-USGS SPARROW modeling effort) or of greatest consequence (such as drinking water sources). States may also choose to prioritize their actions for waters where sufficient information is available to move quickly to adopt numeric criteria in the near-term. The state's nutrient criteria plan should reflect the state's approach to setting standards for its waters and include schedules for adopting those standards.

To be effective, criteria for nitrogen and phosphorus pollution should address causal (nitrogen and phosphorus) and response (chlorophyll-a and transparency) variables for all waters that contribute nitrogen and phosphorus loadings to our waterways. EPA encourages the adoption of standards for all four of these parameters because of the interrelationships between these parameters and its experience showing that controlling both nitrogen and phosphorus is important to successfully combating nitrogen and phosphorus pollution in all waters. As always, states, territories, and authorized tribes have the flexibility to address nitrogen and phosphorus pollution using a subset of or alternatives to these parameters if they are shown to be scientifically defensible and protective of designated uses. Where a state, territory, or authorized tribe shows that one causal variable (nitrogen or phosphorus) is the limiting nutrient, it should develop criteria for at least that nutrient. However, if the non-limiting nutrient is likely contributing to a downstream impairment, numeric criteria for that nutrient should be considered as well.

By accelerating the establishment of numeric water quality standards for nitrogen and phosphorus pollution, state governments and local communities can set goals, establish controls, agree on risk management approaches, measure performance, demonstrate progress, and learn from each other. In a time of scarce resources and competing priorities, we cannot afford delayed or ineffective responses to this major source of environmental degradation. As any environmental professional understands, we can't effectively manage what we can't measure. Numeric environmental baselines help us to measure success, gauge effectiveness, and evaluate alternative approaches.

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Current Status

Photo of a waterbody surrounded by grassy fields and trees
Source: NRCS

Over the last nine years, EPA has taken a number of steps to provide leadership and articulate its goal of working in partnership with states, territories, and authorized tribes to establish quantitative endpoints to minimize excess nitrogen and phosphorus loadings in our Nation's waters. EPA issued a National Strategy for Development of Regional Nutrient Criteria in June 1998, and followed with a November 2001 national action plan for the development and establishment of numeric criteria for nitrogen and phosphorus pollution. EPA published technical guidance for developing criteria for lakes and reservoirs in May 2000, rivers and streams in June 2000, and estuaries and coastal waters in October 2001. EPA also published recommended criteria for nitrogen and phosphorus pollution for most streams and lakes in 2001. This combined strategy of EPA, state, territorial, and tribal partnership supported by technical assistance was intended to jump-start progress on a difficult and challenging problem.

We have made progress, but we need to move more quickly and more comprehensively in order to meet the growing challenges from increasing population, expanding and more intensive agricultural activities, and spreading urbanization. A number of states and territories have already moved ahead to establish numeric standards for priority water bodies. Others are in the process of collecting data and preparing to develop them. Still others are in the earlier stages of planning and deciding which standards development approach will work best for them. A complete overview of the current status (through December 2008) is available.

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Next Steps

EPA remains committed to supporting states' and authorized tribes' efforts to adopt numeric water quality standards for nitrogen and phosphorus pollution that are protective of designated uses. As outlined in more detail in the numeric nutrient standards strategy, EPA will:

  • Provide direct assistance to states close to adopting numeric criteria. For these states, EPA will provide implementation guidance addressing technical and policy issues that states raise, and technical information to support states' rulemaking for standards.
  • Build capacity for states that are not as close to adopting numeric criteria. For these states, EPA will provide sampling/monitoring, training, data/statistical analysis, and modeling assistance for developing criteria numbers.
  • Build a science-based foundation for developing new criteria in estuaries, wetlands, and large rivers. EPA will complete its suite of criteria for nitrogen and phosphorus pollution manuals and continue to work to meet the goals of the federal and state Mississippi River/Gulf of Mexico Watershed Nutrient Task Force.
  • Clearly and effectively communicate data and information on nitrogen and phosphorus pollution. EPA will integrate messages related to nitrogen and phosphorus pollution in water quality standards communications products and outreach.

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Conclusion

Photo of a waterbody with algae near the shore
Source: Michael B. Tate

We can take steps now that will make a difference in addressing the challenges of growing nitrogen and phosphorus pollution. The first step is to have numeric criteria in place to enable action. EPA is committing itself to support development of numeric criteria for nitrogen and phosphorus pollution, and to use EPA's tools and metrics to help states, territories, and authorized tribes adopt numeric water quality standards for nitrogen and phosphorus pollution more quickly. EPA will also continue to conduct research, develop new tools, and collaborate to strengthen partnerships for consensus-based solutions.

EPA will work with states and territories to review their nutrient criteria plans to ensure that they reflect current expectations, set realistic goals, and establish clear interim milestones. Working together, we should ask ourselves what is needed to meet these milestones and then take appropriate action.

We will also continue to work to advance performance measurement and public accountability. EPA recognizes the importance of keeping the public informed of our joint progress. EPA will periodically publish a report of the status of our joint efforts, including the actions EPA has completed and the progress that states have made in adopting numeric water quality standards for nitrogen and phosphorus pollution. EPA will also continue to track progress regarding nitrogen and phosphorus pollution reduction, such as quarterly reporting of the number of TMDLs completed for waters impaired by nitrogen and phosphorus pollution in the Mississippi River Basin.


Additional Resources

Development and Adoption of Nutrient Criteria into Water Quality Standards memo signed on November 14, 2001.

National Nutrient Assessment Workshop, Proceedings: December 4-6, 1995

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