EE/GG 275

Homework 2

  1. Imagine an underground sand aquifer that is 30 meters thick, 400 meters wide and has a hydraulic conductivity of 30 meters/day. The length of the aquifer is 550 meters and the two heights, which determine the height gradient are 115 and 103 meters.

a)     Find the total flow volume per day for this aquifer.

b)    Assume that some pollutant is seeping into the aquifer at a rate of 3kg per day.  What is the pollution concentration in the aquifer?

                                                     i.     As kg per cubic M

                                                      ii.     As PPM (parts per million) Ð assume that 1 cubic meter of water is 62.4lb.

c)     Use the interstitial velocity equation to estimate the speed of water flow through the aquifer. Assume the aquifer is sand-based.

d)   Bonus Question:

                                                     i.     Given the flow rates you estimated, will the pollutant accumulate in the aquifer over time?

                                                      ii.     Estimate the concentration of the pollutant after 1 week

Due in class on Thursday 9/25/03