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**Short Answer**

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13. (head-darcy) **Horizontal** hydraulic conductivity is generally than the **vertical** hydraulic conductivity.

14. (concmod) A **balance** between a model that is simple enough to be workable yet complex enough to be useful is called .

15. (modflow) For an **injection** well, the sign on the flow rate should be .

16. (modflow) A **constant head** boundary is assigned through a combination of the and arrays.

17. (head-darcy) **Above** the ground water table, pore pressures are .

18. (concmod) A unit is a volume of rock or soil that is treated as a single unit due to common **hydraulic** properties.

19. (modflow) If the head in a drain cell is than the drain elevation, the drain has **no effect** on the cell.

20. (modflow) A **river** overlaps a cell in a MODFLOW model. The dimensions of the river in the cell are as follows:

w = average width of the river

L = length of the river reach inside the cell

t = thickness of the river bottom sediments

K = hydraulic conductivity of the river bottom sediments

Enter an expression for the river conductance value to be entered for the cell:

21. (modflow) For the river cell described in the previous problem, assume the following values:

conductance = 680 ft^2/day

stage = 1012.7 ft

river bottom elevation = 1005.3 ft

a. Enter the flow rate (Q) between the aquifer and the river for the cell if the head in the cell = 1014.0 ft:

ft^3/day

b. Enter the flow rate (Q) between the aquifer and the river for the cell if the head in the cell = 1002.6 ft:

ft^3/day