OCR Text |
Show i j How Sand Dunes Were Stopped. On the coast of Gascony there are j points where the dunes push forward i more than four yards annually. In : 17S0 the advance of sand upon the bind of Bordeaux was the occasion of despair to horticulturists and crop growers, and the engineer, Bremontier, made himself famous by converting j the movable dunes into stationary ones. The task was undertaken to ! form a wall against the sand inva-! inva-! sion by making a palisade of the i dunes a little more than a meter high and putting planks between each pair. When the sand swept over the boards It had to break up its volume in the effort, and little by little a stationary dune w-ould form with an Inclination !.of from 7 to 12 degrees in the direc- tion of the sea. Behindthis palisade ! was conveniently disposed a wide zone of the hardier shrubs. |