CONTENTS 



PAGE 



PREFACE iii 



LIST OF ILLUSTRATIONS viii 



LIST OF DIAGRAMS ix 



LIST OF TABLES xi 



CHAPTER I 

 GENERAL CONSIDERATIONS 



Development of Sewerage Systems; Col. Waring's Advocacy of the " Separate 

 System." Arguments for this System as against the " Combined Sys- 

 tem." Conclusions i 



CHAPTER II 



PREPARATORY MAPS AND DATA 



Maps Required; their Scale, Accuracy, and Extent; Information Needed for 

 Maps; Surveys, Methods and Cost; Soundings, Borings; Levels; Speci- 

 fications for Maps submitted to the N. Y. State Dept. of Health .... 13 



CHAPTER III 



EXCESSIVE RAINS 



Brooklyn and Providence Studies; U. S. Weather Bureau Records; Maximum 

 Intensities; Kuichling's Studies; Relation between Intensity and Dura- 

 tion; Talbot's Diagrams; Rochester Diagrams; Other Diagrams 31 



CHAPTER IV 



{/ 

 PROPORTION REACHING THE SEWERS 



Conditions Affecting this Proportion; Early London Gagings; Rochester 

 Gagings; Sudbury River Gagings; European Experience; Kuichling's 

 Conclusions 54 



CHAPTER V 



RELATION OF DENSITY TO PERCENTAGE 



Variety in Impervious Surfaces; Percentage of Rain Discharged from Each; 

 Amount of Impervious Surface Compared with Density of Population; 



Density and Percentage of Rain Discharged Compared 70 



vii 



