This map shows contours of the water table, the location of four factories (labeled A, B, C, and D), and contaminated and uncontaminated wells.Which way will the contamination flow?
A) northeast, up the contours
B) southwest, down the contours
C) northwest and southeast, parallel to the contours
D) impossible to tell because the movement of contamination is independent of groundwater

Question

This map shows contours of the water table, the location of four factories (labeled A, B, C, and D), and contaminated and uncontaminated wells.Which way will the contamination flow? 
A) northeast, up the contours 
B) southwest, down the contours 
C) northwest and southeast, parallel to the contours 
D) impossible to tell because the movement of contamination is independent of groundwater

Quizplus · Accepted Answer

Contamination will generally flow in the direction of the water table gradient, which is perpendicular to the contour lines. In this case, the contour lines indicate that the water table slopes downward to the southwest, which suggests that contamination will flow in that direction, down the gradient. The contaminated wells are also located to the southwest of the factories, further supporting this conclusion.

This Map Shows Contours of the Water Table, the Location