88 THE IMPROVEMENT OF RIVERS. 



into a compactness sufficient to present an effective resistance to the weight of the 

 superincumbent embankment." 



Banquettes. As has been stated, in order to strengthen high levees a terrace is 

 generally built along the land side. This is called a banquette. Its dimensions vary 

 considerably in different localities, its crown at some places being about 20 feet in 

 width, while at others it is twice that amount. It has a very flat slope and usually 

 commences about 8 feet below the top of the levee, and is quite frequently used as a road. 



Levee engineers claim that banquettes should be built at all points where the 

 foundation or material of the levee is weak, and behind all embankments having a 

 height of more than 1 2 feet, regardless of foundation or material, in order to have work- 

 ing-room and material in time of extreme high water. They should be built with the 

 levee and not as a future enlargement, all later enlargements being made on the river 

 side to cover weak spots in the old levee or its berme and to prevent sloughing. 



In addition to strengthening the levee itself, the banquette is an excellent means 

 of re-enforcing the natural ground underneath. This is frequently porous, light, and 

 more or less traversed by roots, etc., and may give way to the pressure from without 

 which will "blow up" the ground inside the levee. By building on this a bench of 

 earth the hydraulic head is diminished. 



The practice of using the banquette as a roadway is not a good one, but as those 

 interested in levees would otherwise have to provide highways at considerable cost 

 it is not practicable to wholly exclude travel. On some of those, where the crown 

 width is about 40 feet, a space of 15 feet next the levee is fenced, the road being placed 

 upon the remainder. In this way the levee is protected and the public accommodated. 

 Some time ago the authorities in charge of levee-building decided to expend no money 

 in improving embankments used as public highways, since which time a marked decrease 

 in this use has been noted, and other roads are being built. In those localities, how- 

 ever, which are many, where it would be impracticable to get a new location within 

 a reasonable cost, the levees are still used. 



Although a roadway along a levee is without doubt injurious in that it allows 

 stock, particularly hogs, to tear it up, and otherwise leads to its damage, there are yet 

 some very good advantages to be derived from it. It facilitates general inspection 

 and weed-cutting, and, in fact, all work pertaining to the construction and mainte- 

 nance of the levee system. If travel be excluded in flood times there is not serious 

 danger to the levee. Even without roadways hogs find their way onto the levees and 

 do much damage. 



Protection. When a levee of any height has been completed it should be well 

 sodded with tufts of Bermuda grass. This is the simplest and most useful of revet- 

 ments; it throws out lateral runners and rapidly covers the surface, and grows well 

 in exposed or sheltered situations. After it is once started it will withstand drought, 

 freezing, and floods, and affords an excellent protection from rains, and even from 

 \vuve wash, where the soil is strong. For a long time there was such strong prejudice 



