Assessment of U.S. Corps Aerators in the San Joaquin River

for the Port of Stockton

September 2004

Jones & Stokes

Russ Brown, Tom Trexler, Megan Robinson

Goals/Objectives

• Determine the current level of performance of both aerators

• Estimate the oxygen loads from the aerators and the oxygen transfer efficiency

• Compare aerator performance to release of oxygen gas from jets and different aerator device (Biox Hose)

View of Aerator Dock

Measurement Efforts

• Measurements in Front of North Jets while Operating Both Aerators

• Measurements in Front of South Jets while using Oxygen Gas

Measurements and Estimations

• Measured Velocity and DO concentrations of upwelling and/or flow-away currents

• Estimated flow-away or upwelling width and calculated flows

• Estimated Oxygen Loads from upwelling or flow-away flows and DO pick-up (measured DO minus background DO)

Operation of Both Aerators

0.0

1.0

2.0

3.0

4.0

0.0 0.5 1.0 1.5 2.0

Average Velocity (ft/s)

Dep

th (

ft)

0 ft 5 ft North 10 ft North 15 ft North

0.0

1.0

2.0

3.0

4.0

0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0

Average Dissolved Oxygen (mg/l)

Dep

th (

ft)

0 ft 5 ft North 10 ft North 15 ft North

Operation of South Jets with Pure Oxygen Gas

0.0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

1.6

-5 0 5 10 15 20

Distance from Jets (ft)

Av

era

ge

Ve

loc

ity

(ft/

s)

South of Jets (5 ft) Centerline North of Jets (5 ft)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

8.0

-5 0 5 10 15 20

Distance from Jets (ft)

Av

era

ge

DO

(m

g/l)

South of Jets (5 ft) Centerline North of Jets (5 ft)

Summary

Both Aerators• DO Pick-up of 0.78

mg/l (Back. DO = 3.2 mg/l)

• Total Flow-away Flow of 90 cfs

• Total Oxygen Supply Rate of 402 lbs/day (assuming 40 ft flow-away width)

South Jets with Oxygen• DO Pick-up of 2.19

mg/l (Back. DO = 2.9 mg/l)

• Avg. Upwelling Flow of 191 cfs

• Avg. Oxygen Supply Rate of 2270 lbs/day

• Oxygen Transfer Efficiency of 45%