Early this week, the United States District Court for the Western District of Missouri sided with multiple state clean water associations and NACWA in denying the request of environmental organizations to overturn EPA’s approval of Missouri’s nutrient water quality standards for lakes. 

At issue in the case was Missouri’s “combined criteria” approach to nutrients which, rather than imposing single numeric limits on total phosphorus and total nitrogen, instead employs a numeric chlorophyll criterion combined with phosphorus, nitrogen, and chlorophyll screening levels that trigger further water quality assessment to determine impairment. 

NACWA joined with the Association of Missouri Clean Water Agencies, Association of Ohio Metropolitan Wastewater Agencies, California Association of Sanitation Agencies, North Carolina Water Quality Association, South Carolina Water Quality Association, Virginia Association of Municipal Wastewater Agencies, and the West Virginia Municipal Water Quality Association in trying to intervene in the case. 

While that intervention was ultimately denied by the court, the state associations and NACWA filed an amicus brief defending Missouri’s approach, which provides much needed flexibility in determining actual impairment while protecting water quality – an issue that is important to states nationwide.

The Missouri Coalition for the Environment Foundation (MCEF), preferring the imposition of stringent numeric criteria, alleged that the state’s approach failed to adequately protect the lakes’ designated uses and was inappropriately tailored to protect sport fish, rather than a wide variety of biota as required by the Clean Water Act (CWA).   

In an unusually frank opinion, however, the court determined that, in approving Missouri’s standards, EPA had not acted arbitrarily or capriciously and therefore the court upheld the standards. 

At the same time, the court agreed with MCEF that the State’s approach “raises significant questions” due to EPA’s “abandonment” of “its well-reasoned [previous] recommendation that the State adopt numeric criteria for nitrogen and phosphorous,” and the concern that the adopted standards “leave Missourians waiting to let the nutrient pollution cause damage to the lakes rather than preventing nutrient pollution in the first place.” The court also implied that political motivations may have played a role in EPA’s decision.

However, despite these thoroughly documented misgivings, the court ultimately determined that EPA had supplied a rational basis on the record for its determination that Missouri’s standards were protective of water quality and in accordance with the CWA. In doing so, the court acknowledged the changes the State made and the additional data the state provided in response to EPA’s critiques of its earlier proposals. The court also upheld EPA’s authority to depart from its earlier position concerning the need for numeric criteria where, as here, the agency gave a rational basis for doing so. 

The decision provides critical support for other states wishing to adopt innovative, scientifically supported approaches to nutrient pollution. Please contact NACWA’s Chief Legal Counsel, Amanda Aspatore, with any questions concerning the decision.