Xll 



CONTENTS 



ing the marks for grade bars, 241 ; Checking up on 

 depth of ditch, 242 ; Breaking the grade, 243 ; Placing 

 the grade bars, 244 ; Checking the bars, 245 ; Grade 

 stakes and finders not needed, 246 ; For more extensive 

 work, 247. 



CHAPTER XI 



DRAINAGE INDICATIONS 



Low flat areas of light soil, 248 ; Considerable slopes 

 of light soil, 249; Extended flat or even moderately 

 rolling areas of heavy soils, 250; Limited flat or de- 

 pressed areas on slopes, 251 ; Limited flat or depressed 

 areas on hilltops, 252 ; Springy low flat areas, 253 ; 

 Springy areas upon slopes, 254 ; Muck or swamp areas, 

 255 ; Small muck areas without natural outlets, 256 ; 

 Shallow ponds resting upon muck beds, 257 ; Shallow 

 ponds resting on other than muck beds, 258 ; Shallow 

 ponds not having sufficient fall or natural outlet, 259 ; 

 Low flat areas whose surfaces lie only slightly above 

 that of an adjacent stream or lake, which cannot be 

 lowered by drainage, 260 ; Situations already referred 

 to, 261. 



CHAPTER XII 

 DRAINAGE AND THE GROUND WATER SUPPLY 



The ground water-table is falling, 262 ; Interesting 

 facts concerning ground water-tables, 263 ; Chief causes 

 resulting in lowering of ground water, 264 ; Increasing 

 the run-off, 265 ; Increasing evaporation, 266 ; The re- 

 moval of surface reservoirs, 267 ; Direct draft upon 

 underground waters, 268 ; The interpretations placed 

 on the fact of a falling ground water-table, 269 ; Crop 

 needs, 270 ; Animal needs, 271 ; The meaning of the 

 lowering of the ground water-table in terms of rainfall, 

 272 ; Intelligent soil management needed, 273 ; The case 

 not serious, 274 ; The real relation of drainage to capil- 

 lary and ground water, 275 ; The experience of other 

 countries, 276 ; Optimism, 277. 



187-199 



200-207 



