Embankments require to be made with great care. The earth should be deposited in layers. In Holland, horses are driven up and down over each layer. In some parts of India the earth for embankments is brought from the borrow pits by scoops drawn by bullocks. The earthwork is of so excellent a character, owing to the earth being trodden down, that no settlement has to be allowed for. Where the soil is sand the top and faces of the embankment should be of good stiff soil, if it can be obtained, for a thickness of 9 inches or a foot, or else the face next the river should be protected by fascining (CHAP. VI., _Art. 3_) for 2 feet above, and several feet below high flood-level. Such protection may be necessary in any case where waves are liable to occur. In Holland embankments are turfed, and trees and shrubs are not allowed to grow. In the Punjab the growth of all kinds of jungle is encouraged. It binds the soil together and protects it from the wash of waves and from winds which blow away sand and dust, and so wear the embankment slowly away. In embanking a long reach of a river it is convenient to begin from the upstream end, because otherwise floods may get behind the finished part of the embankment and, becoming impounded in a “pocket” formed by the embankment and high land, rise to an abnormal height and, unless gaps in the embankment have been left or are subsequently made, cause breaches. During high floods pegs should be driven in at frequent intervals, to mark the high flood-levels. If a higher flood occurs, the peg is shifted. The levels of the pegs can be observed at leisure. When a breach occurs in an embankment, the first thing to do is to protect the ends so that the breach shall not lengthen. If the water passing through a breach becomes pocketed, the embankment may have to be cut to let it out. Regarding the stoppage of leakages, see CHAP. IX., _Art. 1._ Regarding the closure of breaches, see CHAP. VII., _Art. 2_. For a description of flood embankments along the great shifting rivers of Northern India, see _Punjab Rivers and Works_. _Note to Art. 5._--Floods can sometimes be mitigated by sinking pits in the flooded area so that the flood water comes in contact with permeable strata and is absorbed by them. CHAPTER XIII RESERVOIRS AND DAMS