(a) Calculate the hydraulic residence times (the retention time) for Lake Superior and for Lake Erie using data in Table 4.4.
(b) Assume that both lakes currently are polluted with the same compound at a concentration that is 10 times the maximum acceptable level. If all sources of the compound are removed, how long will it take the con-centration to reach acceptable levels in each lake? Assume that the pollutant does not decay chemically.
(c) Comment on the significance of your answers.
