xii PREFACE 



water, problems. These scientists are in the Departments of 

 Agriculture, Army, Commerce, and Interior and several in- 

 dependent Federal agencies; in state water surveys or geolog- 

 ical surveys or conservation departments or state engineers' 

 staffs; in industrial concerns and consulting engineering, geo- 

 logical, or water-supply firms. Reference is made to some of 

 the published data in descriptions of specific problems or case 

 histories. The author owes these men much more — ideas that 

 he has gained in discussions and correspondence and in work- 

 ing with them, as well as suggestions and criticisms concern- 

 ing parts of the manuscript; also verification of the data con- 

 tained in the thumbnail sketches of 70-odd problem areas in 

 35 states. These sketches, used to illustrate the types of 

 ground-water problems occurring in the nation, describe 

 areas which in the aggregate produce nearly two thirds of the 

 ground water that the Nation takes from wells. 



The author is especially indebted to Stephen W. Bergen, 

 of the research staff of The Conservation Foundation, who 

 worked with him throughout the period of the survey and 

 assisted in the compilation and organization of the data and 

 in the assembly of this volume. 



Harold E. Thomas 

 Salt Lake City, Utah 

 March, 1951 



