This study was carried out at Gezira area in Central Sudan that lies between longitude 32° and 32° 50＇ and latitude 14° and 14°15＇. It dealt with the history of the sand, its source and rate of m...This study was carried out at Gezira area in Central Sudan that lies between longitude 32° and 32° 50＇ and latitude 14° and 14°15＇. It dealt with the history of the sand, its source and rate of movement towards Gezira scheme and monitored the trend of blowing sand over 10 years. To find out the origin of drifting sand, sand samples were collected from the sandy area west to the White Nile and from the study area. Heavy minerals analysis was carried out on these samples and its mineral assemblage was matched with the mineral of both sand at western bank of the White Nile and the Blue Nile. To picture the trend of moving sand, Multispectral Scanning System （MSS, 1975）, and Thematic Map （TM, 1985） were used to delineate the sandy areas and their trend with time. The rate of the blowing sand was quantified using Bottemane sand catcher. The heavy mineral results showed that the mineral of the drifting sand in the study area are quite similar to the sand of sand dune west to the White Nile indicating the same origin. The sand was transported by southern and southwestern winds through a corridor across the White Nile to its eastern bank, where the most likely water transported sediment was reworked by wind and transported further to the northeast. Between 1972 and 1985, the sand invaded the area at an average rate of about 30 km2 per year and map of 1985 demonstrated a corridor across the White Nile for sand movement. The area was subject to 7 days sand storm with an average of 35 kg/m.d and in summer time, the average amount of moving sand was about 28 kg/m.d. These results demonstrated the future hazard of drifting sand and its impact, which has to be tackled immediately to protect Gezira scheme.展开更多
文摘This study was carried out at Gezira area in Central Sudan that lies between longitude 32° and 32° 50＇ and latitude 14° and 14°15＇. It dealt with the history of the sand, its source and rate of movement towards Gezira scheme and monitored the trend of blowing sand over 10 years. To find out the origin of drifting sand, sand samples were collected from the sandy area west to the White Nile and from the study area. Heavy minerals analysis was carried out on these samples and its mineral assemblage was matched with the mineral of both sand at western bank of the White Nile and the Blue Nile. To picture the trend of moving sand, Multispectral Scanning System （MSS, 1975）, and Thematic Map （TM, 1985） were used to delineate the sandy areas and their trend with time. The rate of the blowing sand was quantified using Bottemane sand catcher. The heavy mineral results showed that the mineral of the drifting sand in the study area are quite similar to the sand of sand dune west to the White Nile indicating the same origin. The sand was transported by southern and southwestern winds through a corridor across the White Nile to its eastern bank, where the most likely water transported sediment was reworked by wind and transported further to the northeast. Between 1972 and 1985, the sand invaded the area at an average rate of about 30 km2 per year and map of 1985 demonstrated a corridor across the White Nile for sand movement. The area was subject to 7 days sand storm with an average of 35 kg/m.d and in summer time, the average amount of moving sand was about 28 kg/m.d. These results demonstrated the future hazard of drifting sand and its impact, which has to be tackled immediately to protect Gezira scheme.
