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Some Quiz Questions. Unit: Subsurface Flow. Question for understanding. In general , ground water does not move between two points 1 and 2 when … ( check all correct answers, one or more ) points 1 and 2 have the same pressure points 1 and 2 are at the same elevation
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Some Quiz Questions Unit: Subsurface Flow
Question for understanding • In general, ground water does not move between two points 1 and 2 when … (check all correct answers, one or more) points 1 and 2 have the same pressure points 1 and 2 are at the same elevation points 1 and 2 have the same energy points 1 and 2 are in a soil with very low permeability
Question for understanding • For water flow between points 1 and of 2 in the curved tube in the sketch below, when calculating hydraulic gradient i = Δh1,2/L, (a) L = L1, (b) L = L2 or (c) L = L3?
Problem related to the quiz question on next slide • For the flow field in the figure below, calculate discharge (for a cross section perpendicular to the –horizontal– flow direction equal to 1 m2) when the hydraulic conductivity is 8640 m/day και 432 m/dayin layers 1 and 2, respectively. In addition, calculate hydraulic head at cross sections at points Η and Μ and sketch a map with the equipotential lines (lines of equal hydraulic head). Boundaries ΑΒ and CD are no flow boundaries and boundaries ΑCand ΒD are constant head boundaries, with known –as shown in the figure– hydraulic head, h
Question for understanding • Given the answershH=4.67m, hM=1.33 m, for the problem of the previous slide, which one do you prefer among the three maps (a, b, or c) shown equipotential lines? (a) (b) (c)
Question for understanding • Theaverage linear velocityor seepage velocity ...(check all correct answers) is the Darcyvelocity divided by porosity is discharge divided by the portion of the cross section that is available for flow gives good estimates when used in calculations of travel time of contaminants in laboratory experiments is a good approximation of the actual groundwater velocity within the soil pores
Question for understanding • TheLaplace equation (2h=0) is valid when we have... (check all correct answers, one or more) constant fluid density homogeneous andisotropic soil no pumping, no injection something else
Kerogene*(LNAPL) release in coarse sand:estimate saturation, So Residual saturation,So=? LNAPL lens: possibility of pumping – further movement, So=? water table * dyed red