Development of Nutrient Criteria for Indiana’s Surface Waters

The national goals of the Clean Water Act are to achieve, wherever attainable, water quality which provides for the protection and propagation of fish, shellfish, and wildlife and recreation in and on the water. As part of state and tribal water quality standards, the Clean Water Act requires states and authorized tribes to specify designated uses for their waters in consideration of these goals, and to adopt water quality criteria that protect those designated uses. Most waters in Indiana are designated for uses such as warm-water aquatic life, full body contact recreation, and drinking water supply. Excess amounts of nitrogen and phosphorous have been identified as causes for several waters not meeting these designated uses. Indiana is in the process of developing criteria for these nutrients. For rivers and streams, IDEM is utilizing the Environmental Protection Agency’s (EPA) technical guidance to refine and develop nutrient criteria. The methods used will be dependent on the result of the analysis of available data. In order of preference, these approaches are: (a) effect-based which correlates nutrient levels with measurable water quality or biological effects or impairments utilizing available data, and (b) reference-based which utilizes a percentile of the frequency distribution of all sites for different water body types based on Indiana-specific data and ecoregions. IDEM and the U.S. Geological Survey (USGS) are working collaboratively to develop criteria for rivers and streams. For lakes and reservoirs, candidate endpoints for nutrient criteria have been developed by Limno-Tech, Inc., and Tetra-Tech, Inc., utilizing multiple lines of analyses including stressor-response and frequency distribution approaches. These end points will be the basis for final criteria decisions to be made as part of the rulemaking process.

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Shivi  Selvaratnam Coordinator, Water Quality Standards Program
Indiana Department of Environmental Management
sselvara@idem.in.gov

Shivi joined the Indiana Department of Environmental Management (IDEM) in 2005 and is the Water Quality Standards coordinator in the Office of Water Quality. Her primary responsibilities include the management of programs related to the review and revision of WQS, and the development of surface water quality criteria. Prior to joining IDEM, Shivi worked in academia for eight years where she taught courses in biology and microbiology and carried out researched on the effects of agricultural pollution on microbial communities in streams. Shivi received a B.A. in biology from Monmouth College, a Ph.D. in microbiology from Drexel University and completed her post-doctoral work in environmental microbiology at the University of Notre Dame.