30 BULLETIIs^ 181^ U. S. DEPAETMEXT OF AGEICULTTJKE. 
LEVEES. 
The ground should be carefully inspected to secure the best loca- 
tion. The locations as shown on the map may be varied from when- 
ever by so doing advantage can be taken of higher or firmer ground. 
In no case should a levee be located less than 200 feet from the bank 
of the river, and care should be taken to protect the levels against 
washing or undermining at the sharp bends of the stream. Changes 
in direction should be made by easy curves rather than by sharp 
angles. 
The base should be cleared of all vegetation and stumps, and the 
large roots removed. For levees more than 10 feet high a muck 
ditch about 3 feet deep and 6 feet wide should be dug along the 
center line of the embankment. This ditch may be filled as is any 
other portion of the levee. The surface of the ground on which the 
levee is to be built should be broken with a plow, so that a bond will 
be formed which will prevent seepage from following the surface 
between the old and the new material. 
The soil of which the levees are to be built is a heavy river silt or 
clay and will form a strong and fairly impervious embankment. The 
durations of the extreme high-water stages will be short, so that the 
levees will not ordinarily be saturated for more than a few feet from 
the ground surface. The estimates for the levees have therefore 
been based on a top width of 4 feet, side slopes of 2^ to 1 on water 
side and 1^ to 1 on land side for river floodway levees, and 3 to 1 on 
water side and 2 to 1 on land side for the creek floodway levees. 
This difference in slopes is recommended because of the fact that 
the creek floodway levees will be subjected to a current of greater 
velocity than will those of the river floodway. 
The levees should be built of clean earth that is free from vegeta- 
ble matter taken from the side of the levee next to the waterway. 
The pits from which the earth is taken should have side slopes at 
least as flat as 1 to 1 ; and if practicable should not be more than 6 
feet deep. Along the river levees a berm or strip of land at least 
10 feet wide, from which no earth has been taken, shoifld be left 
between the pit and the toe of the levee. For the creek floodway 
levees the berm should be 50 feet wide and the borrow pit of the 
shape specified. The widths of right of way for levees were com- 
puted by adding to the width of base and berm, the width of borrow 
pit, based upon a depth of 6 feet and side slopes 1 to 1. 
The material can be most economically handled by a dry-land 
excavator of some type that will take the material from the pit and 
place it in the levee at one operation. When the required amount of 
material is in place, the top and sides of the embankment should be 
smoothed to an even surface and the whole planted in any grass 
adapted to the soil and chmate. 
