Assignment task:
Using Water - Worksheet 4 (second image), lightly draw contours of the water table surface in the area of the 21 wells. Use the same contour interval as that used for elevation (50 m). As you have already learned in earlier questions, contours for potentiometric surfaces (like the water table) are typically very smooth, often far smoother than the contours for surface topography. Sketch your contours accordingly, at first using light pencil so you can modify as you proceed. Note that, where there is surface water (such as the Abalone River), the water table should come to the surface. This means that the water table contours should meet the topographic contours at the river.
Groundwater flow immediately beneath the water table follows the hydraulic gradient: it flows from high water table elevations to low. Thus, groundwater flow will be approximately perpendicular to the water table contours.
IMPORTANT:
Using this principle, lightly draw flow-lines (with arrow heads indicating direction) that pass through the locations of the recycling depot, the gas station, and the paint shop. Indicate, by circling the location, where the pollution affecting well N most likely came from.