Water Protection Program

Development of Nutrient Criteria for Water Quality

In 2001, the U.S. Environmental Protection Agency published water quality criteria for nutrients (nitrogen and phosphorus) as called for in section 304(a) of the Clean Water Act. These criteria were developed as a starting point for states, authorized tribes, interstate commissions, et al., to develop criteria that would be appropriate for their own jurisdictions. This approach was due to the recognition that the determination of suitable limits for nutrients for water bodies is a highly complicated issue. It is governed by wide variation in local ecological conditions, as well as the uses placed upon the waters. Too much nutrient loading to a water body can cause rapid growth of algal blooms, organic enrichment and depletion of dissolved oxygen. Too little may result in insufficient enrichment of the aquatic food chain, which would be detrimental to a healthy aquatic biological community.

Developing the nutrient criteria that will protect the waters of the state requires significant analysis of water quality data. It also requires input from citizens concerned with the impact of implementation of nutrient criteria. With this in mind, a plan for developing nutrient criteria in Missouri was developed in 2005 and is presented here.  There is also an update of the proposed schedule for development.

Lakes

Nutrient criteria for lakes and reservoirs were adopted as part of the water quality standards rule in October, 2009.  The part of the rule applicable to nutrients is at 10CSR 20-7.031(4)(N), on page 16.  The department has drafted a policy for implementation of the rule, which is now under review by stakeholders. In August, 2011, US EPA denied approval of a substantial part of this rule, expressing some technical issues with the criteria that were introduced.  The department is in the process of addressing these concerns, with the goal of including them as part of ongoing revisions to the water quality standards.

Rivers and Streams

Stakeholders began meeting in 2009 for briefings on how criteria development for streams will proceed.  These meetings were suspended so a technical workgroup could take the time necessary to make recommendations for criteria that will be scientifically defendable and sufficiently protective of the state's streams and rivers.  Criteria will be based on a compilation of several lines of evidence, including a statistical review of available data, a USGS study of algae response to nutrients in the Ozarks, and analyses of macro-invertebrates and chlorophyll-a as response variables.  When all analyses are complete, stakeholder meetings will be reconvened for consideration of the recommendations.

Upcoming Meetings
Nutrient Criteria Technical Subcommittee
May 9, 2012 Postponed - TBA
Lewis and Clark State Office Building
1101 Riverside Dr.
Jefferson City

Past Meetings

April 5, 2012
Meeting Notes
Presentation: Primary Lake Fish Kills and Alternative Lines of Evidence
The Florida Situation
Agenda
Video

Feb. 9, 2012
Agenda
Lines of Evidence
Meeting Notes
Presentation: Lines of Evidence
Presentation: Chlorophyll Maxima

Sept. 21, 2011
Agenda
Minutes
EPA letter on nutrient criteria
EPA presentation

July 19, 2011
Meeting Summary
Agenda
Nutrient Criteria Implementation Procedure
Nutrient NPDES Flow Chart
Tables A1-A6
Tables B1-B11

Nov. 16, 2010
Meeting Summary
Examination of Algal Community Data for Establishment of Nitrogen and Phosphorus Criteria
Nutrient Criteria Database Quality Assurance and Statistical Analysis
Draft Rule: Nutrients in Streams
Biological Response to Nutrients in Central Plains Regional Streams of Missouri
Ecological Indicators
Table 5: Matrix of Summary Statistics
Nutrient Lines of Evidence

Feb. 11, 2009
Meeting Summary
Presentations and handouts Nutrient Plan, Nutrient Benchmarks 1MB

March 10, 2009
Meeting Summary
Presentations and handouts Criteria by other States