Sand dunes (English: Sand Dunes) are sand accumulations that are defined and defined by the influence of the wind, and therefore they can change their shape, size and location depending on the direction and strength of the wind.
Sand dunes form in sandy deserts as well as in sandy coasts, but sand dunes that form on beaches are smaller, depending on the size of the sand grains and the strength of the winds.
On the beaches, sand dunes are usually arranged parallel to the coast, thus helping to protect other areas from the influence of marine factors (sea waves, storms and winds) and from the effects of sea salinity .
Sand dune shape
All sand dunes have a wide base, and two sides can be distinguished:
- The front side (which is exposed to the wind), is dune-oriented, with a steeper slope.
- Back side (the other side not facing the wind), with a much less steep slope.
The top of the dune is known as the summit, and it separates the front from the back.
Sand dune shapes
There are several types of sand dunes that differ in shape:
Crescent sand dunes
These sand dunes are similar in shape to the crescent shape, and they can reach a height of 5-10 meters, and in some cases it may reach 35 meters. The direction of the crescent arms is to the direction of the winds in the same area.
Crescent sand dunes are dangerous and cause harmful effects on the environment, vegetation cover and residential communities, because it is difficult to install or control them. Plants cannot grow on them because of their permanent movement that causes the uprooting of plants or exposing their roots, or it can cause plants to be buried in neighboring places. . In addition, these sand dunes do not retain moisture and water in them, which makes it impossible for plants to grow on them.
Arch sand dunes
Arc dunes are in the shape of an elongated crescent (from the inside they look like a horse’s hoof) and flow against the crescent dunes, where the direction of the crescent arms is against the direction of the wind.
Longitudinal sand dunes
The longitudinal sand dunes called Al-Arouq are sand dunes that reach a height of several meters, and they can rise to 250 meters, as is the case in Iran.
These sand dunes are long and sometimes hundreds of kilometers, like the sand dunes in the Sahara Desert .
Pyramid sand dunes
Pyramid sand dunes are like a pyramid in shape and may be tens of meters high. These sand dunes are formed as a result of winds blowing from several directions, and they do not pose a threat to the environment and vegetation, because they are exposed to winds from all directions and do not move and move from one place to another.
Petrified sand dunes
Sand dunes can sometimes harden into stable structures. Sand becomes a rock type and is called sandstone. These sand dunes are called mountain dunes. Examples of petrified sand dunes can be found in the US states of Utah and Hawaii.
Where are the highest sand dunes?
Cerro Blanco is one of the highest sand dunes in the world, and is located in the Sechora Desert, Peru. Its height is about 1176 meters.
How to install sand dunes
Sand dunes may need to be stabilized in order to reduce damage to dunes. The following are the most popular installation methods:
Sand dunes can be stabilized by reducing the speed and quantity of winds. If the wind becomes slower, it loses the sand it carries and drops it, which means reducing the likelihood of sand dunes forming or reducing their height and their impacts on the environment, vegetation and places of population.
Mechanical installation can be done by creating barriers to prevent and defend against the wind, this prevents the access of a lot of winds to the places of sand dunes, barriers are created by planting certain types of trees that can withstand and resist strong winds, and some materials that install sand dunes can also be sprayed .
This is the best way to install sand dunes, and in which tree vegetation is planted over the sand dunes, this vegetation contributes to stabilizing the sand grains and holding them together, any type of evergreen tree such as acacia can be used.
Can the danger of sand dunes be reduced?
The danger of sand dunes can be reduced by following some measures such as:
- Create fences, walls and windbreaks, which prevent the winds from carrying more sand to the sand dunes or moving them.
- Use of shovels and bulldozers to reduce sand accumulations in a place and prevent more gathering.
- Planting sand dunes and establishing vegetation cover over them if possible. This prevents the sand particles from moving and makes them cohesive in place.
Sand dunes are formations of sand that differ in shape, size and height. These dunes can form in desert places or sandy coasts, and they can also move from one place to another under the influence of the winds, which may make them dangerous to the environment and public life.
Many countries of the world are combating the formation of sand dunes and preventing their movement towards residential and agricultural places, by building barriers and barriers in their path.
Vegetation is one of the best liquid that contributes to reducing sand dunes and their damage.