Physical and Chemical Properties of Complex and Compound Nabkhas in Kadhma Area Northern Kuwait Bay

Abstract

The accumulation of aeolian sand around single plant is known as nabkhas, if it is around two plants it is called compound nabkhas, while if it is around more than two plants it is then called a complex nabkha and all are classified as anchored dunes. The compound and complex nabkhas are formed around dominant native plants in open desert and sabkhas in Kuwait. Morphological measurements were taken from a field of nabkhas formed around the plant “Nitraria retusa” in Khadhma area. Around 120 surface and core samples (down to a depth of 100 cm at each 10 cm) were collected in order to identify the morphological, sedimentological and chemical properties. The particle size, organic and moisture content, biological activity, acidity, electrical conductivity were measured for compound and complex nabkhas. The particle size for compound and complex nabkhas are varying upon location in the body of nabkhas and each type has its own distinguishing properties. There is reality that all nabkha deposits contain more fine sand in the wind ward (tail) sides compared to the mid of nabkhas. Graphical and inter-relation figures succeed in distinguishing between compound and complex nabkhas. The complex nabkha is characterized by normal distribution with increase in medium and coarse sand fractions with a percentage reaching more than 50%. The volume of the sand body in complex and compound nabkhas are 376.7 m3 and 14 m3 respectively. The complex dune is composed of a coalescence of 51 nabkhas with average 40 degree from north towards west, parallel to the dominant wind direction in the area. The sediment samples from the compound and complex dune is basic, dry with normal electrical conductivity and low organic matter content. The sample are with a medium mean size distribution, poorly sorted, normal skewness and very platy kurtic. This study showed that the importance of the sand body in the nabkhas is as nutrient and water storage rather than as a shield protecting the nabkhas from sand blasting. This sand body attracts native animals to a marvellous ecological interaction especially in complex nabkhas. the nabkhas use drought periods to catch more mobile sand in order to increase the volume size and to increase in water body.