The Blue Ox Tannery has asked you to assist them in preparations to file for a NPDES permit to discharge wastewater into the Zmellsbad River. The DNR water quality criterion for the Zmellsbad River is 5.00 mg/L of DO. They have asked you the following questions: What is the critical DO and where (at what distance) downstream does it occur? They have provided you with the following data. They pertain to the 7-year, 10-day low flow at the tannery. Blue Ox Zmellsbad Parameter wastewater River Flow, m3/s 1.148 7.222 BOD5 at 158C, mg/L 90.00 N/A BODu at 158C, mg/L N/A 7.66 DO, mg/L 1.00 6.00 Temperature, 8C 15.0 15.0 k at 208C, d21 0.3685 N/A Speed, m/s N/A 0.300 Depth, m N/A 2.92 Bed-activity coefficient N/A 0.100