Page 162 - Hydrogeology Principles and Practice
P. 162

HYDC05  12/5/05  5:34 PM  Page 145






                                                                    Groundwater investigation techniques  145


























                   Fig. 5.4 Diagram showing the change in aquifer stress conditions caused by an increase in atmospheric pressure from P in (a) to P + dP
                                                                                            A      A  A
                   in (b) resulting in a decrease in groundwater level (ψ − ψ′) in a confined aquifer.







































                   Fig. 5.5 Relationship between groundwater level fluctuation and atmospheric pressure in Chance Well 3 (CW-3), Long Valley Caldera,
                   California (well depth 267 m; altitude 2155.90 m above sea level; latitude 37º38′49″, longitude 118º51′30″). At this site, water level and
                   barometric pressure are monitored using a pressure transducer and barometer, respectively. These data are recorded on a data logger
                   every 30 minutes and the data transmitted by satellite to the United States National Water Information System database.
   157   158   159   160   161   162   163   164   165   166   167