calculating water gradient

  • Calculate the average water table gradient or slope along the western flow line (i.e., area west of the groundwater divide) between the 200 ft contour and the 50 ft contour. Give your answer in ft/ft (round-off to two decimal places) Show your work; use units. (hint: print out the map and cut out the scale (ruler) at the lower right to measure the horizontal distance between two contours.) [2.5 points]
  • Calculate the average groundwater velocity in the vicinity of the western flow line given the hydraulic conductivity (K) of the aquifer = 150 ft/day and the effective porosity (ne) = 5%. Show your work; use units or suffer dire consequences. [2.5 points]
  • On the map, construct a groundwater flow line downslope from each of sites A, B, and C. [2.5 points]
  • If gasoline were spilled at sites A, B, and C, where would it directly discharge into? (Label them on the map). [2.5 points]
  • In the eastern part of the aquifer, at and down gradient from B, the hydraulic conductivity (K) is 100 ft/day and the effective porosity (ne) is 30%. Calculate the average velocity along the flow line from B. First you must calculate the hydraulic gradient (slope of the water table) for the flow line from B. It may or may not be equal to the hydraulic gradient you already calculated in question #(1). Show your work; use units. [5 points]
  • If the velocity of the groundwater is assumed to also represent the movement of the contaminant, what is the time required for gasoline spilled at site B to travel to the end of the flow path? First you must measure the distance between point B and the end of the flow path. Round-off distance in feet to one decimal place, round-off time in days to whole days, and round-off years to one decimal place. Show your work; use units.

[5 points]