274 MISCELLANEOUS FARM SUBJECTS 



ing animals. The slight damage to a levee which may result from 

 using it as a pasture is easily observed and repaired and is probably 

 Counterbalanced by the good results of the practice. 



The surface washing of hillsides results in great loss to farmers 

 by depleting the fertility of the cultivated land, not infrequently 

 causing the abandonment of entire fields to weeds, briers and broom 

 grass. The terrace system which is commonly employed to prevent 

 washing consists of a series of small ridges constructed across the 

 slope on contour lines at intervals the width of which depends upon 

 the degree of the surface slope. These ridges are sometimes placed 

 as close together as 20 feet. As the ridges are at least 4 feet in 

 width, 16 per cent of the land is thus occupied. It is not uncommon 

 to find entire fields terraced at 100-foot intervals, in which cases 4 

 per cent of the land is occupied by the ridges. The object of their 

 construction is to retain the rainfall until it can pass into the soil by 

 slow percolation. In some cases the trench on the upper side of the 

 terrace is given a gentle grade for the purpose of leading the water 

 to some point where it can be taken to the stream at the foot of the 

 slope. The ridges serve as a series of small dams which, when they 

 break, as they frequently do, cause the water to wash away consid- 

 erable soil, and break one or more of the terraces 'below. Such 

 breaks often open out washes during a single rainstorm, which are 

 costly to repair and which, if neglected, seriously injure the field. 

 The permeability of hill-land soil to water varies greatly, as does the 

 slope and contour of the surface. Farmers usually vary but little 

 their practice of terracing, applying the same system of construction 

 to all hill lands. (Wis. Ex. Sta. B. 199; Kept. OS. Ex. Sta. 1906; 

 Ex. Sta. B. 243; Kept. Off. Ex. Sta. 1909.) 



Failures. Experience has shown that the stability of a levee is 

 dependent upon its location, cross section, material used in construc- 

 tion, and maintenance. If all these conditions were ideal there 

 would be no levee failures, but in practice it is not often possible to 

 get them. Locations must be used which leave the foundation and 

 slopes exposed to erosion by currents and waves. Such material as is 

 at nand must be used, and the funds available often determine the 

 size of the cross section. The ideal material for levee construction 

 is a heavy tenacious earth which will not erode or dissolve when sub- 

 jected to the direct action of water and will resist percolation under 

 hydrostatic pressure. Of the available materials found in river bot- 

 toms gumbo and buckshot are the best. In many places complaints 

 are made of the ravages of muskrats. It is stated that they burrow 

 in the embankment and cause it to give way during periods of high 

 water. This trouble can be greatly lessened, if not entirely avoided, 

 by keeping the embankment free from a rank growth of vegetation. 

 It should be mowed at least twice a year and the material cut at once 

 removed. This will destroy the harbor for these animals, and the 

 damage they do can be more readily detected and repaired. Where 

 an embankment is constructed by a number of landowners there 

 seems to be a division of responsibility, and no one looks after it and 



