Find: DOB mg L A B C chloride=0 2.3 3.7 7.5 9.7 Stream A C Q [m3/s] 6.2 T [C] 19.4 21.0 D [mg/L] 4.49 3.58 o o mg L B A C flow chloride=0 2.3 3.7 7.5 9.7 Find the dissolved oxygen in Stream B, in milligrams per liter. [pause] In this problem, ---

Find: DOB mg L A B C chloride=0 2.3 3.7 7.5 9.7 Stream A C Q [m3/s] 6.2 T [C] 19.4 21.0 D [mg/L] 4.49 3.58 o o mg L B A C flow chloride=0 2.3 3.7 7.5 9.7 Stream A, and Stream B, converge, to create Stream C.

Find: DOB mg L A B C chloride=0 2.3 3.7 7.5 9.7 Stream A C Q [m3/s] 6.2 T [C] 19.4 21.0 D [mg/L] 4.49 3.58 o o mg L B A C flow chloride=0 2.3 3.7 7.5 9.7 The flowrates, temperatures, and oxygen deficits, in Streams A and C, are provided. [pause] For sake of convenience, ----

Find: DOB mg L A B C Stream Q [m3/s] T [C] D [mg/L] A 3.7 21.0 4.49 B 6.2 19.4 3.58 A C flow we’ll add an additional row, for stream B. The concentrations of dissolved oxygen --- B

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow in the three streams are related to each other by their flowrates.

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow The dissolved oxygen concentration in Stream B is a function of the dissolved oxygen concentrations in ---

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC DOB = Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow Streams A and C, as well as the flowrates, in all 3 streams. [pause] The problem statement provides the flowrates --- DOC * QC - DOA * QA DOB = QB

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC DOB = Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow in streams A and C. And the flowrate in Stream B is equal to --- DOC * QC - DOA * QA DOB = QB

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC DOB = Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow the flowrate in stream C, minus the flowrate in stream A, which equals, ---- DOC * QC - DOA * QA DOB = QB QB = QC - QA

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC DOB = Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow 2.5 meters cubed per second. We’ll add this value to the table. DOC * QC - DOA * QA DOB = QB QB = QC - QA QB = 2.5 [m3/s]

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC DOB = Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow [pause] The last two unknown variables, --- DOC * QC - DOA * QA DOB = QB QB = QC - QA QB = 2.5 [m3/s]

Find: DOB mg L A B C DOA * QA + DOB * QB = DOC * QC DOB = Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA * QA + DOB * QB = DOC * QC B A C flow are the dissolved oxygen concentrations, in Stream A and Stream C. [pause] DOC * QC - DOA * QA DOB = QB

Find: DOB mg L A B C DO = DOSAT - D Stream Q [m3/s] T [C] D [mg/L] A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DO = DOSAT - D B A C flow The concentration of dissolved oxygen ---

Find: DOB mg L A B C DO = DOSAT - D Stream Q [m3/s] T [C] D [mg/L] A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DO = DOSAT - D B A C flow in a stream, equals, the saturated --- mg dissolved oxygen L

Find: DOB mg L A B C DO = DOSAT - D Stream Q [m3/s] T [C] D [mg/L] A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DO = DOSAT - D B A C flow concentration of dissolved oxygen, minus, --- saturated mg dissolved oxygen L mg dissolved oxygen L

Find: DOB mg L A B C DO = DOSAT - D Stream Q [m3/s] T [C] D [mg/L] A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 oxygen mg DO = DOSAT - D deficit L B A C flow the oxygen deficit. For this equation, we’ll be working in units of --- saturated mg dissolved oxygen L mg dissolved oxygen L

Find: DOB mg L A B C DO = DOSAT - D Stream Q [m3/s] T [C] D [mg/L] A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 oxygen mg DO = DOSAT - D deficit L B A C flow milligrams per liter, and we’re out to calculate the dissolved oxygen for --- saturated mg dissolved oxygen L mg dissolved oxygen L

Find: DOB mg L A B C DOA= DOA, SAT - DA Stream Q [m3/s] T [C] D [mg/L] 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA B A C flow Stream A, [pause] and for Stream C.

Find: DOB mg L A B C DOA= DOA, SAT - DA DOC= DOC, SAT - DC Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA B A C flow DOC= DOC, SAT - DC For each of these equation we’ve been provided the oxygen deficits, D, ----

Find: DOB mg L A B C DOA= DOA, SAT - DA DOC= DOC, SAT - DC Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA B A C flow DOC= DOC, SAT - DC of 4.49 milligrams per liter, and 3.58 milligrams per liter. The saturated concentration of dissolved oxygen ---

Find: DOB mg L A B C DOA= DOA, SAT - DA DOC= DOC, SAT - DC ƒ(T,CCl-) Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA B A C flow DOC= DOC, SAT - DC is a function of the temperature and chloride concentration, of the water. [pause] Since the problem statement provides the ---- ƒ(T,CCl-)

Find: DOB mg L A B C DOA= DOA, SAT - DA DOC= DOC, SAT - DC ƒ(T,CCl-) Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA B A C flow DOC= DOC, SAT - DC temperatures and chloride concentrations, the corresponding saturated DO concentrations are looked up in a table of values, and equal --- ƒ(T,CCl-) mg L chloride=0

Find: DOB mg L DOA= DOA, SAT - DA = 8.99 -4.49 DOC= DOC, SAT - DC Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA 8.99 milligrams per liter in Stream A, and 9.28 milligrams per liter in Stream C. The resulting dissolved oxygen concentrations are --- mg L mg = 8.99 -4.49 L DOC= DOC, SAT - DC mg L mg = 9.28 -3.58 L

Find: DOB mg L DOA= DOA, SAT - DA = 8.99 -4.49 = 4.50 Stream Q [m3/s] T [C] D [mg/L] o A 3.7 21.0 4.49 B 2.5 o C 6.2 19.4 3.58 DOA= DOA, SAT - DA 4.50 milligrams per liter, and 5.70 milligrams per liter, for Streams A and C, respectively. --- mg mg mg L = 8.99 -4.49 = 4.50 L L DOC= DOC, SAT - DC mg mg mg L = 9.28 -3.58 = 5.70 L L

Find: DOB mg L DOA= DOA, SAT - DA = 8.99 -4.49 = 4.50 Stream Q [m3/s] T [C] D [mg/L] DO [mg/L] o A 3.7 21.0 4.49 4.50 B 2.5 o C 6.2 19.4 3.58 5.70 DOA= DOA, SAT - DA [pause] Returning to our original equation for the concentration of --- mg mg mg = 8.99 -4.49 = 4.50 L L L DOC= DOC, SAT - DC mg mg mg = 9.28 -3.58 = 5.70 L L L

Find: DOB mg L A B C DOB = Stream Q [m3/s] T [C] D [mg/L] DO [mg/L] A 3.7 21.0 4.49 4.50 B 2.5 o C 6.2 19.4 3.58 5.70 DOC*QC - DOA*QA DOB = B A C flow dissolved oxygen in Stream B, the known values are plugged into the equation, --- QB

Find: DOB mg L A B C DOB = Stream Q [m3/s] T [C] D [mg/L] DO [mg/L] A 3.7 21.0 4.49 4.50 B 2.5 o C 6.2 19.4 3.58 5.70 DOC*QC - DOA*QA DOB = B A C flow and the concentration of dissolved oxygen, in Stream B equals, --- QB

Find: DOB mg L A B C DOB = DOB =7.48 Stream Q [m3/s] T [C] D [mg/L] DO [mg/L] o A 3.7 21.0 4.49 4.50 B 2.5 o C 6.2 19.4 3.58 5.70 DOC*QC - DOA*QA DOB = B A C flow 7.48 milligrams per liter. QB mg L DOB =7.48

Find: DOB mg L A B C DOB = 2.3 3.7 7.5 9.7 DOB =7.48 Stream Q [m3/s] T [C] D [mg/L] DO [mg/L] o A 3.7 21.0 4.49 4.50 B 2.5 o C 6.2 19.4 3.58 5.70 DOC*QC - DOA*QA DOB = B A C flow 2.3 3.7 7.5 9.7 When reviewing the possible solutions, --- QB mg L DOB =7.48

Find: DOB mg L AnswerC A B C DOB = 2.3 3.7 7.5 9.7 DOB =7.48 Stream Q [m3/s] T [C] D [mg/L] DO [mg/L] o A 3.7 21.0 4.49 4.50 B 2.5 o C 6.2 19.4 3.58 5.70 DOC*QC - DOA*QA DOB = B A C flow 2.3 3.7 7.5 9.7 the answer is C. QB mg L DOB =7.48 AnswerC

? Index σ’v = Σ γ d γT=100 [lb/ft3] +γclay dclay 1 Find: σ’v at d = 30 feet (1+wc)*γw wc+(1/SG) σ’v = Σ γ d d Sand 10 ft γT=100 [lb/ft3] 100 [lb/ft3] 10 [ft] 20 ft Clay = γsand dsand +γclay dclay A W S V [ft3] W [lb] 40 ft text wc = 37% ? Δh 20 [ft] (5 [cm])2 * π/4