Numeric Nutrient Criteria
Staff Contact: Michael Suplee (406) 444-0831
DEQ is developing numeric water quality criteria intended to control excessive nutrient (nitrogen and phosphorus) pollution in Montana's streams, rivers, and lakes. The intent of numeric nutrient criteria is to assure a level of water quality that will protect the beneficial uses of these waterbodies. DEQ has strived to base the numeric nutrient criteria on the best available science and data.
Our understanding of how and when nitrogen and phosphorus impact streams and small rivers has reached the point where we are now moving into the beginning of the rule-making phase for these waterbodies. Rule making will involve not only the numeric nutrient criteria themselves, but also how they will be implemented. The public will be afforded opportunities to provide comment to DEQ and the Board of Environmental Review both before and during rule making.
This website contains some of the key technical reports completed as part of the stream and small river criteria-development process. The website will be updated periodically with additional reports and other information as the development of numeric nutrient criteria for other surface waters proceeds.
- Criteria Technical Reports - Large Rivers
- Using a Computer Water Quality Model to Derive Numeric Nutrient Criteria: Lower Yellowstone River (2013)
- Appendix C - Please extract this zip file to a folder on your computer to access.
- Appendix C - Please extract this zip file to a folder on your computer to access.
- Using a Computer Water Quality Model to Derive Numeric Nutrient Criteria: Lower Yellowstone River (2013)
- Criteria Technical Reports - Wadeable Streams
- Scientific and Technical Basis of the Numeric Nutrient Criteria for Montana's Wadeable Streams and Rivers - Update 1 (2013)
- Scientific and Technical Basis of the Numeric Nutrient Criteria for Montana's Wadeable Streams and Rivers (2008)
- Updated Statistical Analyses of Water Quality Data, Compliance Tools, and Change Point Assessment for Montana Rivers and Streams (2008)
- Seasonally Stratified Water Quality Analysis for Montana Rivers and Streams – Final Report (2005)
- Reference Study Report (2005)
- Nutrient and algal biomass criteria recommendations for Northeastern Montana (2004)
- Economic Consideration Reports
- Demonstration of Substantial and Widespread Economic Impacts to Montana that would Result if Base Numeric Nutrient Standards had to be Met by Entities in the Private Sector in 2011/2012 (2012)
- Demonstration of Substantial and Widespread Economic Impacts to Montana That Would Result if Base Numeric Nutrient Standards had to be Met in 2011/2012 (2012)
- Scoping Evaluation of Economic Impact Assessment Methodologies for Water Quality Standards (2007)
- Wastewater Treatment Performance and Cost Data to Support an Affordability Analysis for Water Quality Standards (2006)
- Nutrient Work Group
