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Department of Civil & Environmental Department of Civil & Environmental EngineeringEngineering
University of UtahUniversity of Utah
Sediment Oxygen Demand & Nutrient Flux Studies in Jordan
River
Dr. Ramesh GoelDr. Ramesh GoelAssistant ProfessorAssistant Professor
Civil & Environmental EngineeringCivil & Environmental EngineeringUniversity of UtahUniversity of Utah
CONCEPT ON SEDIMENT OXYGEN DEMAND (SOD)
Sediments
WaterO2Nutrients
Organics etc
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
HowHow to Measure SOD?to Measure SOD?
PumpPump
DOT = Sediments + Water column DOW = Water column only
SOD = DOT – DOW
Methodology
Schematic of SOD Chamber
CONTROL
ANALYSIS
Equation used for the SOD rate:
SOD t = sediment oxygen demand rate (g/m2d)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 (m2)1.44 = units-conversion constants
SOD20 = the rate at 20°C t = in °C
Source: Parkhill and Gulliver, 1997
SOD Rate Estimation
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/m2-day
Initial linear data is used
SOD RatesLocation
CoordinatesTemperatu
re(0 C)
SOD rate
(g/m2-day)
SOD20oC(g/m2-day)
980 S, 900 W (Peace Gardens)
19.78 7.56 7.66
280 N, 1460 W 22.27 1.93 1.67
4800 S, 580 W 19.83 2.18 3.77
Legacy Nature Preserve
22.13 3.9 2.89
9000 S ,900 W 16.02 1.54 1.20
Difficulties
Bed-sediment heterogeneities Measurement errors
Possible disturbances during chamber placements
Sampling errorsControl chamber data
fluctuations
Acknowledgements Mr. James Harris, Utah Department
of Water Quality Mr. Carl Adam- Utah DWQ Leland Myers- Great inspiration The whole water quality personnel
Questions???
Thank You!!!