A Literature Review for use in Nutrient Criteria Development for Freshwater Streams and Rivers in Virginia

To protect the designated uses of streams and rivers, the U.S. Environmental Protection Agency (U.S. EPA) is directing states and authorized tribes to develop numeric criteria for nutrients. As a part of the efforts in Virginia, the Virginia Department of Environmental Quality requested specifically that the Academic Advisory Committee conduct a comprehensive literature search on the following topics: • Investigate methods for defining undesirable (nuisance) levels of periphytic algae in wadeable streams, and what such studies have concluded as undesirable (nuisance) levels. • Investigate a corresponding approach to planktonic algae in non-wadeable streams. The purpose of this review is to provide background information for the interested public, the Academic Advisory Committee, and the Virginia Department of Environmental Quality to facilitate discussions concerning nutrient criteria development in Virginia. The review aims to identify approaches that could help Virginia in its task of developing nutrient-related numeric criteria for non-tidal freshwater streams and rivers and highlights criteria values defined in other areas through application of such methods. Section I contains background information pertaining to nutrient criteria development, nitrogen, phosphorus, and primary production. Section II provides information about and examples of research or criteria proposed in other regions that pertain to the approaches recommended by the U.S. EPA for establishing numeric nutrient criteria. These approaches include: (1) the reference approach, (2) the predictive relationship approach, and (3) the published nutrient criteria and threshold approach. Section II also includes information about the development of numeric criteria to protect downstream waters. Section III of the review provides an alternative approach to developing numeric nutrient criteria proposed by the Kansas Department of Health and Environment but not yet reviewed by the U.S. EPA. This alternative approach emphasizes nutrient reductions by adhering to a developed nutrient export budget. This document does not provide information on many issues that need to be discussed before Virginia sets numeric nutrient criteria. The literature review, therefore, should not be used to select numeric values for non-tidal freshwater streams and rivers in Virginia simply based on the research or criteria of others. Additional work is needed to address issues not discussed in this review.