PROTECTING RIVER BANKS FROM CAVING.

New Zealand Times, Volume XLIV, Issue 7488, 28 May 1885, Page 4

PROTECTING RIVER BANKS FROM CAVING.

A novel system of protecting river banks against the consuming action of an ever-flow-ing current is being applied near Memphis,Tennaesee, along the Mississippi, where a caving bank rises straight up from the water’s edge from 10 to 50 feet. There is an incessant lapping and chafing by which the bank is slowly worn away and undermined, and. as a consequence, it breaks down piece by piece, and is dissolved and carried away by the river. To check this steady but slow disintegration is the problem which United States engineers are trying to solve satisfactorily. The idea of a blanket placed along the slope of the bank from high water mark to the bed of the'river naturally suggested itself, andthe contrivance adopted, a willow and pole mattress, represents the blanket theory. The woven webs are some 50 feet wide and from 200 to 1000 feet in length, with flexible willows worked in for woof and poles and wire for warp. These are made on boats having a length equal to the width of the mattress, and as the mattresses are completed they slide away into the water. The sunken mattresses, it is said, prevent undermining below the low water line, and the grading down of the overhanging bank stops the undermining above that line. The space between the upper edge of the mattresses and the top of the bank is protected with willows and stone. All this mattress-grading and stonecovering is embraced in the term revetment. Fhe work already done by the American engineers and the staff of workmen under them is described as being of the most sub* stantial character. The appropriation of 200,000 dola. secured from the last Congress for this work will, it is estimated, be sufficient to place mattresses along the river front from Wolf River to the foot of Beal or Linden streets. The work will probably he completed before the next rise of the river. 11 remains to be seen whether it will hold the bank and prevent it from farther caving. N ext spring, when the floods turn the Mississippi, into a inland sea, the practical test will be made, and, if the mattresses hold the banks successfully against the impinging and undermining current, the mattressrevetment theory will be sustained.—lron.