EPA Recommendations for Nutrient Criteria Require Clarification

Posted on Friday, September 25th, 2020 | Posted in News

On August 20, NEIWPCC submitted a comment letter to the EPA in response to their draft numeric nutrient criteria recommendations for lakes and reservoirs.

Accurately quantifying acceptable levels of nutrient loading is complicated, which is why most states set narrative, rather than numeric, water quality criteria for nutrients. While many states are eager to implement numeric nutrient criteria, EPA’s draft left many questions unanswered.

The EPA’s draft recommendations consolidate national data sources to provide model-based ways for states to calculate and create numeric criteria.

The models are technically complex to understand and implement. The 123-page document was supported by over 600 pages of additional documentation, eight models in R computer code, four interactive R-shiny apps, and several additional datasets.

However, this extensive technical documentation did not provide states with clear guidance on how to implement these recommendations to set criteria which effectively protect waters from nutrient pollution.

NEIWPCC asked for significant clarification, guidance, and training from the EPA to help states understand and implement the recommendations.

“States must be able to fully understand the models and their underlying assumptions in order to make sound, defensible decisions regarding water quality standards.”

NEIWPCC shared states’ concerns that the draft criteria recommendations do not fully address natural variation in lake nutrient conditions, that the underlying data do not fully represent conditions in the Northeast, and that recommendations fail to address the combined impacts of climate change and nutrient loading on lake conditions.


Autumn on the river

More Time to Review

In June, NEIWPCC and others requested more time for the states to review the draft recommendations, which the EPA introduced in May.

The EPA did extend the public comment period by 30 days, allowing NEIWPCC time to work with state environmental officials to provide more detailed feedback in August.

However, NEIWPCC asked “that these draft Criteria Recommendations not be finalized until EPA has provided the clarifications and resources” requested.