ga THE IMPROVEMENT OF RIVER*. 



prevent this escapement. This has been done in the protection of cities, but is too 

 expensive to secure general application. 



The high waters of recent years in the Mississippi valley have demonstrated pretty 

 thoroughly the necessity for a complete drainage of levees in order to overcome this 

 difficulty. Ditches of sufficient capacity to carry away all seep- water are cut along 

 the base of the embankments, and little ditches are made down the slope into them. 

 The latter lead the waters off as rapidly as they percolate through the pores. This 

 prevents the softening of the material and the sliding which would otherwise take place. 

 This practice is becoming pretty general and has proved quite effective, judging by 

 the reports of engineers who have resorted to it. When the sloughing has been started 

 it may be checked by driving heavy stakes well into the embankment and bracing 

 them back to similar stakes. In front of the first row of stakes, brush, saplings, or 

 any convenient wood must be laid horizontally to form a barrier for the earth to lodge 

 against. Brush is also placed upon the portion sloughed and covered with earth until 

 the normal levee section is practically restored. 



Another method of the treatment of sloughing levees is quoted from a Govern- 

 ment report: "Treatment of sloughs is simple if the principle involved be understood. 

 It is usually the case if one occurs where an inexperienced man is at work, that he will 

 endeavor to restore the lost section with earth or sacks. This does no good, but rather 

 tends to augment the trouble, because it makes it more difficult to drain the slough 

 and at the same time puts that much more weight on the semifluid mass to squash 

 it out; squashing the sloughed mass out invariably pulls with it some of the standing 

 sections. He does this because he does not understand what produces the slough. 

 He does not know it is caused by too free leakage through the embankment, and insuffi- 

 cient land-side drainage. 



"It is a well-known fact that if any vessel encountering hydrostatic pressure be 

 leaking, the leak can be more expeditiously stopped from the outer or pressure side 

 than from the inner side, provided, of course, the opportunities for reaching both are 

 equally good. If a barge, for example, loaded with coal starts a leak in a side seam, 

 it is impracticable to dig away the coal to get at it. It is equally impracticable to 

 detect the leak by feeling along the outer side of the barge as the inflow is too light to 

 be detected by hand. But the deckhand can take a supply of coarse sawdust, and, by 

 means of a long handle, can lower a cup of sawdust into the water in close proximity 

 to the leak, shaking it gently next to the barge, and as the sawdust floats out of the 

 cup some of it is drawn into the crack and becomes lodged; it very shortly swells and 

 the leak is choked. Just so it is with seeping levees, but their treatment consists in 

 dumping loose earth in the water over the river slope. The particles of earth are drawn 

 into the interstices, become swollen, and shortly the leak is choked. The layman who 

 sees this work in progress will immediately classify dumping loose earth in the water 

 as sheer nonsense and not possible of practical results, but as a matter of fact, in a short 

 while after work has been commenced, the good effects will be shown by reduced 



