MAP NO. 3. — SKETCH MAP OF NORTHEAST CHINA 



Showing the alluvial plain and the Grand Canal, extending 800 miles through it from Hang- 

 chau to Tientsm. The unshaded land area lies mostly less than 100 feet above sea-level 



the miles of canals and leveed rivers in 

 China, Korea, and Japan equal to eight 

 times the ntimber represented on map 

 No. 2 — full}/ 200,000 miles in all. 



THE GREAT EEVEES 



As adjuncts to these vast canaliza- 

 tion works there have been enormous 

 amounts of embankment, dike, and levee 

 construction. More than 300 miles of 

 sea wall alone exist in the area covered 

 by the sketch map (page 933). The east 

 bank of the Grand Canal above Yang- 

 chau is itself a great levee, holding back 

 the waters to the west above the eastern 

 plain, diverting them south into the 



Yangtse-kiang ; but it is also provided, 

 with spillways for use in times of exces- 

 sive flood, permitting waters to discharge 

 eastward. Such excess waters, how- 

 ever, are controlled by another dike, with 

 canal along its west side, some 40 miles 

 to the east, impounding the water in a 

 series of large lakes until it may grad- 

 ually drain away. This area is seen in 

 map No. 3, above, north of the Yangtse 

 River. 



Along the banks of the Yangtse, and 

 for many miles along the Hwang-ho, 

 great levees have been built, sometimes 

 in reinforcing series of two or three at 

 dififerent distances back from the chan- 



934 



