Question

2. (15 points) The following figure shows a clay layer under an earth-filled dam with a reservoir on the right side and a pond on the left side of the dam. (1) (10 points) Determine the seepage loss through the clay layer when hydraulic conductivity K = 10-4 m/s, H = 20 m, L = 50 m, and b = 10m. (2) (5 points) A chemical company suddenly dumps a conservative chemical substance into the reservoir. Assuming that the chemical instantly mixes with the reservoir water, approximately how long it would take for the contaminant to get to the pond on the left side? The effective porosity of the clay layer ne = 0.25. Water surface Water surface Impervious dam Flow Datum

Answer 1

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Let us look into the explained solution directly.

Solni Impers Dam TH=2om blom Datum , L = som from Darcy's law, (tang = kxi) QP = A x yang = Axkxi m3/sec is Headloss (He) = H = 20 = 0.48. length k= 107 m/sec., I 50 A = bxd m² व a length A = b meter = lom Since conth of Dam Isn't given, we will calculated avere discharge/ unit length of Dam, (9) m3/sec/m. 9 = kxix A = 10-4X 0:4XL0

9 = 0.4X10-3 m3/sec / length of Dama ③ contaminant flows with seepage velouty, velocity which is obtained by considering the fact that flow occurs only through interconnecting voids. Q = A total x Vars = Aroid X Vseepage Vseepage - Vang (na porosity) Vseepage = kxê to 48014 : 0.25 V seepage = 1.6x107 meter/sec.

travel to to pond Time taken (seconds) = Distance o Vseepage - someter xxA 1.68109 m/s. : Time = 312500 seconds elbooth anos Time = 3.616898 days alone
I have explained what is seepage velocity and why we calculated discharge per unit length of the dam. In case if you still have doubts use the comment section to clear them. Please upvote if you liked the solution. Stay at home and safe from coronavirus. Thank you.