{"id":1362,"date":"2026-05-12T21:47:40","date_gmt":"2026-05-12T21:47:40","guid":{"rendered":"https:\/\/books.gw-project.org\/basic-hydrogeology-an-introduction-to-the-fundamentals-of-groundwater-science\/chapter\/exercise-14\/"},"modified":"2026-05-13T03:34:43","modified_gmt":"2026-05-13T03:34:43","slug":"exercise-14","status":"publish","type":"chapter","link":"https:\/\/books.gw-project.org\/basic-hydrogeology-an-introduction-to-the-fundamentals-of-groundwater-science\/chapter\/exercise-14\/","title":{"raw":"Exercise 14","rendered":"Exercise 14"},"content":{"raw":"
\r\n
\r\n\r\nPart 1: A pumping well has a known efficiency of 90\u00a0percent at a pump rate\u00a0of 500\u00a0m3<\/sup>\/d. Would the measured drawdown in the well be greater than the expected drawdown or less than the expected drawdown?\r\n\r\n<\/div>\r\n
\r\n\r\nPart 2: At a pumping rate of 600\u00a0m3<\/sup>\/d, would you expect the efficiency to be higher\u2014that is, greater than 90\u00a0percent\u2014or lower\u2014that is, less than 90\u00a0percent? Justify your answer.\r\n\r\n<\/div>\r\n
\r\n\r\nPart 3: A pumping well is installed in a confined aquifer with a known transmissivity (0.0003\u00a0m2<\/sup>\/s) and storativity (0.0004). The diameter of the borehole used to install the well is 0.30\u00a0m.\r\n\r\n<\/div>\r\n
    \r\n \t
  1. Using the radius of the borehole (0.15\u00a0m) as [latex]r[\/latex], calculate the drawdown in the well after 24\u00a0hours of pumping at 500\u00a0m3<\/sup>\/d.<\/li>\r\n \t
  2. The well is pumped for 24\u00a0hours, and the measured drawdown in the well is 17 meters. Calculate the well efficiency for that pumping rate and determine the amount of well loss.<\/li>\r\n<\/ol>\r\n
    \r\n\r\nPart 4: An aquifer test is performed in a pumping well with no observation wells (i.e., a single\u2011well aquifer test). The resulting transmissivity is 1,000\u00a0ft2<\/sup>\/d. If we assume that the well has an efficiency of 75\u00a0percent, which of the following three statements is the most appropriate? Circle one and justify your answer.\r\n\r\n<\/div>\r\n
      \r\n \t
    1. The test provides a good estimate of the actual formation transmissivity.<\/li>\r\n \t
    2. The test results overestimate the actual formation transmissivity.<\/li>\r\n \t
    3. The test results underestimate the formation transmissivity.<\/li>\r\n<\/ol>\r\n
      \r\n\r\nSolution for Exercise 14<\/u><\/strong><\/span><\/a>\u2ba7\r\n\r\n<\/div>\r\n
      \r\n\r\nReturn to where text linked to Exercise\u00a014<\/strong><\/span><\/a>\u2ba5\r\n\r\n<\/div>\r\n<\/div>","rendered":"
      \n
      \n

      Part 1: A pumping well has a known efficiency of 90\u00a0percent at a pump rate\u00a0of 500\u00a0m3<\/sup>\/d. Would the measured drawdown in the well be greater than the expected drawdown or less than the expected drawdown?<\/p>\n<\/div>\n

      \n

      Part 2: At a pumping rate of 600\u00a0m3<\/sup>\/d, would you expect the efficiency to be higher\u2014that is, greater than 90\u00a0percent\u2014or lower\u2014that is, less than 90\u00a0percent? Justify your answer.<\/p>\n<\/div>\n

      \n

      Part 3: A pumping well is installed in a confined aquifer with a known transmissivity (0.0003\u00a0m2<\/sup>\/s) and storativity (0.0004). The diameter of the borehole used to install the well is 0.30\u00a0m.<\/p>\n<\/div>\n

        \n
      1. Using the radius of the borehole (0.15\u00a0m) as [latex]r[\/latex], calculate the drawdown in the well after 24\u00a0hours of pumping at 500\u00a0m3<\/sup>\/d.<\/li>\n
      2. The well is pumped for 24\u00a0hours, and the measured drawdown in the well is 17 meters. Calculate the well efficiency for that pumping rate and determine the amount of well loss.<\/li>\n<\/ol>\n
        \n

        Part 4: An aquifer test is performed in a pumping well with no observation wells (i.e., a single\u2011well aquifer test). The resulting transmissivity is 1,000\u00a0ft2<\/sup>\/d. If we assume that the well has an efficiency of 75\u00a0percent, which of the following three statements is the most appropriate? Circle one and justify your answer.<\/p>\n<\/div>\n

          \n
        1. The test provides a good estimate of the actual formation transmissivity.<\/li>\n
        2. The test results overestimate the actual formation transmissivity.<\/li>\n
        3. The test results underestimate the formation transmissivity.<\/li>\n<\/ol>\n
          \n

          Solution for Exercise 14<\/u><\/strong><\/span><\/a>\u2ba7<\/p>\n<\/div>\n

          \n

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