1. Missouri Nutrient Criteria Plan Mark Osborn October 20, 2005

2. Problems caused by nutrient enrichment Causative factors –Total Nitrogen –Total Phosphorus Response factors –Turbidity –Excessive Algae Growth –Oxygen Reduction –Organic Enrichment –Hypoxia in Gulf of Mexico

3. EPA Response Criteria recommendations for each nutrient ecoregion Encourage development of nutrient criteria plans by states and tribes Development of Regional Technical Assistance Groups (RTAG)

4. EPA Recommendations Specify Criteria by Ecoregions Identification of Reference Conditions Account for cause and response relationships Specific Criteria Development –25th percentile of all lakes and streams within ecoregions –75th percentile of reference lakes and streams

6. Omernic Level III Ecoregions in EPA Region VII

7. Seston Chlorophyll-a as a function of watershed size R 2 = 0.4372

8. Mean Total Nitrogen as a Function of Watershed Size R 2 = 0.0001

9. RTAG regressions of nutrient cause and response variables: x = Total Nitrogen

10. RTAG regressions of nutrient cause and response variables: x = total phosphorus

11. RTAG regressions of nutrient cause and response variables: x = watershed size

12. RTAG regression of nutrient cause and response variable: x = Turbidity

13. Missouri Nutrient Criteria Plan Plan has been approved by EPA Water body type –Lakes –Small Streams –Wetland –Big River

14. Nutrient Criteria Plan for Lakes in Missouri Substantial data has been collected by Jack Jones et al. 1976-1984, 1989-2002 Most lakes in the state are artificial, therefore use of reference conditions is not practical EPA’s suggested lake nutrient criteria would place 75% of Missouri’s lakes in non-compliance Significant differences in TP and TN between lakes in different eco-regions Lake size and retention time also has impact on cause and response variable concentrations

15. Eco-Regions for Lakes in Missouri Big Rivers Ozark Highlands Plains

16. Geometric Lake Means for Total Phosphorus and Chlorophyll

17. Nutrient Criteria Plan for Lakes in Missouri Issues –Variations in cause/response relationships due to regional characteristics and lake morphology –Low threshold for TP concentration resulting in high chlorophyll response (20 μg/L) –Criteria for designated uses may conflict with each other e.g. WBC vs Aquatic Life support

18. Nutrient Criteria Plan for Lakes in Missouri - Approach Develop Criteria for Designated Uses –Whole Body Contact –Aquatic Life Support –Drinking Water Response Variables –Secchi Depth –Turbidity –Total Organic Carbon for Drinking Water

19. Nutrient Criteria Plan for Lakes in Missouri - Approach Lake Morphology (Obrecht, 2005) –Retention Time –Land Use in Watershed –Mainly applicable in Central Irregular Plain area

20. Nutrient Criteria Plan for Streams in Missouri Reference Streams –selected and identified by macroinvertebrate taxa richness Data to be evaluated by ecological drainage unit –More specific than Omernik III Ecoregions –May cross boundaries from other classifications –Based on Distinctions in Aquatic Biology

21. Ecological Drainage Units and Reference Stream Sites in Missouri

22. Nutrient Criteria Plan for Wetlands in Missouri Classification to be based on method by Cowardin et al. –Systems - basic hydrology (riverine, lacustrine, palustrine) –Subsystems - specific hydrology (lower perennial, upper perennial, intermittent, etc.) –Class - Type of dominant vegetative and/or substrate materials Development schedule undetermined at this time

23. Nutrient Criteria for Big Rivers in Missouri Still under development