SAN JOAQUIN RIVER Dissolved Oxygen Total Maximum Daily Load (SJR DO TMDL) Stakeholder Process

Chris Foe comments on Russ Brown’s report entitled "Evaluation of aeration technology for the Stockton Deep Water Ship Channel". Overall, a very nice report. Page 5-6. A general comment on the section entitled "Dissolved oxygen sag in the DWSC". I believe your estimate of the worst-case amount of reaeration is low. Typical flows through the DWSC are more like 1,000 cfs (not 500 as used in your example); values as high as 3,000 cfs have been measured. A consequence of this is that "typical" oxygen demand may be more like 54,000 lbs/day not 27, 0000 lbs/day. Worse-case scenarios may be more on the order of 100-150,000 lbs/day (flow rates of 3,000 cfs but hopefully somewhat lower BOD values). This will have the ultimate effect of significantly increasing the cost of aeration. A second comment, not for you but perhaps more for Fred Lee’s synthesis report, is that the equation at the bottom of page 6 says that oxygen demand or the amount of reaeration needed increases with both increasing flow and increasing concentrations of oxygen requiring substances. This is important because the Steering Committee is presently evaluating two implementation options that are in conflict with each other: aeration and increased flow. If the Committee decides to primarily solve the problem by reaeration then it may wish to keep flow as low as possible. Alternatively, the Committee may wish to try and increase upstream flow (maybe through Old River) to attempt to decrease upstream algal concentrations but this will decrease the efficiency of reaeration. The trade-off of these two options will have to be evaluated carefully. Page 27 Assume units in column 3 of table 1 are lbs O2 per kilowatt-hour of electricity? We probably could achieve further savings by going to another energy source such as natural gas. No page. Is there any readily available source of pure oxygen near Stockton? Could the facility supply variable amounts of pure oxygen up to say 50,000-100,000 lbs/day? Some calling around might be worthwhile. No page. A potential difficulty not addressed in the report is that the oxygen sag is a function of flow. At low flows the maximum depletion sits above R5 but at hi flows it is moved as far downstream as Turner Cut (see Regional Board Target report). Also the magnitude of the depression is variable depending upon the magnitude of the load of upstream oxygen requiring substances. This suggests that the efficiency of the aeration device will improve considerably if it can be moved up or down the channel and is capable of delivering a variable amount of oxygen. Maybe we will end up using the barriers at the head of Old river to regulate flow and hold the oxygen depression in a constant position in the channel. Again, overall a very nice report. Thanks.