1. Sediment Concentration to Water Discharge Ratio Along the Mississippi (and Missouri) River CE 397 Statistics of Water Resources Yao You

2. Key Points Sediment concentration to water discharge ratio decreases downstream; Sediment concentration does not reach the limit of river capacity most of the time.

3. Sediment Concentration Against Discharge Anoka, MN Flow velocity increases correlation coefficient: 0.6804

4. The Ratio Compared to Discharge Anoka, MN Flow velocity increases

5. The Ratio Compared to Discharge St. Louis, MO Flow velocity increases

6. Data Source Very few sites have both consistent (suspended) sediment concentration and water discharge data; Qualified sites have uneven data points (3-20); Data comes from different time periods.

7. Treatment of Data Few sites: nothing we can do right now... Small number of data points: rank sum+t test Time period issue: test for trend.

8. Results downstream

9. Majority Trend: Upstream ≥ Downstream downstream ≥≥

10. Exception: Upstream < Downstream downstream < St. Louis, MO

11. Sudden Increase of Sediment Concentration Near St. Louis, MO St. Louis Missouri River, major sediment supplier for MS Mississippi River

12. Missouri River

13. Missouri River: Results St. Louis Upstream has much larger concentration to discharge ratio;

14. Missouri River: Results St. Louis Upstream has much larger concentration to discharge ratio; The ratio increases near Sioux, IA and Omaha, NE.

15. Conclusions Sediment concentration to discharge ratio decreases downstream; Missouri River contributes a significant amount of sediment into the Mississippi River upstream of St. Louis, MO; Rivers are not at their full transport capacity most of the time.

16. Future Work Understand the physics of the observed trends; Study more rivers to verify those findings.