376 WOOD TRANSPORT BY WATER. 



artificial works, to render the floating more regular and to 

 avoid damage. In strong or weak waters there are always a 

 number of hindrances: the banks may require securing; it 

 may be necessary to remove obstructions from the bed of the 

 stream, by blasting, or otherwise ; sometimes the current 

 requires modifying, or bifurcations of the stream should be 

 cut off whilst floating is in progress. 



i. Strengthening the Banks of Streams. 



Artificial works may be employed with advantage wherever 

 the banks of a stream are too steep, or too sloping, or. where 



Fig. 248. Fig. 249. 



Methods of strengthening the river bank. 



the breadth of the stream requires modification. High, steep 

 or vertical banks of a stream, if not of hard rock, get under- 

 mined and fall in, holes being formed in which the wood 

 sticks ; or the material of the bank may be carried away and 

 form an obstruction lower down the stream. Wood which 

 lodges against the bank becomes at length waterlogged, and 

 may be lost. Hence, all bad banks require facing. Wherever 

 the bank is composed of mere earth, a slope of 25 to 30 degrees 

 should be given to it, and it should be sodded or planted with 

 willow-cuttings to give it firmness. If a current sets in 

 against such banks they may be protected by wattle-work, 

 a trench being dug along the bank, a wjittlo-work fence 



