|
The
erg oases in the Algerian Souf region with artificial craters
(bur) dug out and protected by barriers of leaves, regulate the
dune movements and shape the great sandy desert landscape.
|
|
|
The
formation of artificial sand dunes called afreg in the Sahara
Desert. The method exploits the natural principle of dune formation.
The dunes originate from the sand transported by the wind that
accumulates when it finds an obstacle or a deposit of sand, which
stop the grains of sand from bouncing ahead. The figure above
shows a raw earth cordon which creates the first accumulation
of sand on the ground. Then dry palm leaves are progressively
laid on the top as the sand dune rises. As time goes by, formations
reaching up to 100 m. in height generate beautiful pyramidal artificial
dunes such as the one in the figure below.
|
 |
|
Aerial photograph of an oasis showing the structural elements: the artificial dune; the path of the drainage tunnel in the depression of the dune and the palm-grove extending according to a geometrical shape, following the gravitational line of flow and division of the water and depending on the quantity of water produced by the drainage tunnel.
|
|
|
Morocco.
Vegetable fibre barriers to stop soil erosion and provide protection
from sandstorms.
|
|
|
Erg oases situated in artificial sandy craters (bur) typical of the Algerian Souf region. The dunes protect the oases at the perimeter and the palm trees, which directly soak up water form the subsoil, create a microclimate suitable for horticulture.
|
|
