1. Department of Civil & Environmental Engineering University of Utah Sediment Oxygen Demand & Nutrient Flux Studies in Jordan River Dr. Ramesh Goel Assistant Professor Civil & Environmental Engineering University of Utah

2. CONCEPT ON SEDIMENT OXYGEN DEMAND (SOD) Sediments Water O2O2 Nutrients Organics etc

3. SEDIMENT OXYGEN DEMAND SOD is a combination of all of the oxygen-consuming processes that occur at or just below the sediment-water interface. Most of the SOD at the surface of the sediment is due to the biological decomposition of organic material and the microbially facilitated nitrification of ammonia SOD several centimeters into the sediment is often dominated by the chemical oxidation

4. How to Measure SOD? Pump DO T = Sediments + Water columnDO W = Water column only SOD = DO T – DO W

5. Methodology Schematic of SOD Chamber

6. CONTROL ANALYSIS

8. Equation used for the SOD rate: SOD t = sediment oxygen demand rate (g/m 2 d) b = slope of the oxygen-depletion curve (mg/L- min) V = the volume of the chamber (L) A = the area of bottom sediment covered by the chamber (m 2 ) 1.44 = units-conversion constants SOD 20 = the rate at 20°C t = in °C Source: Parkhill and Gulliver, 1997 SOD Rate Estimation

9. SOD- 2300S site Slope of SOD 1 = 0.0065 mg/L-min Slope of Control =0.0005 mg/L-min Net SOD = 0.0065-0.0005 =0.0060= 0.006 * 1.44 * 240 =2.073 g/m 2 -day Initial linear data is used

10. SOD Rates Location Coordinates Temperature ( 0 C) SOD rate (g/m 2 - day) SOD20 o C (g/m 2 - day) 980 S, 900 W (Peace Gardens) 19.787.567.66 280 N, 1460 W 22.271.931.67 4800 S, 580 W 19.832.183.77 Legacy Nature Preserve 22.133.92.89 9000 S,900 W 16.021.541.20

11. Difficulties  Bed-sediment heterogeneities  Measurement errors Possible disturbances during chamber placements Sampling errors Control chamber data fluctuations

12. Acknowledgements  Mr. James Harris, Utah Department of Water Quality  Mr. Carl Adam- Utah DWQ  Leland Myers- Great inspiration  The whole water quality personnel

13. Questions??? Thank You!!!