Salinisation Research Papers - Academia.edu (original) (raw)
In the first half of this century, British and Egyptian-Sudanese engenieers headed by H.E. Hurst and others thoroughly studied the hydrology of the Nile basin (Hurst, 1952) (Fig. 16.1). The basin has a total length of 6,671 km and the... more
In the first half of this century, British and Egyptian-Sudanese engenieers headed by H.E. Hurst and others thoroughly studied the hydrology of the Nile basin (Hurst, 1952) (Fig. 16.1). The basin has a total length of 6,671 km and the average discharge at Aswan has remained about 90 km3/a over the last 100 years, althought monthly and annual discharge rates vary considerably. From early studies and more recent data (Wittington and Guariso, 1983) a scheme of inputs and outputs can be drawn for the Nile river. It is apparent that the tropical lakes are not the main source of the Nile. Although 34.6 km3/a enter the Sudd from the southern lakes and 11.8 km3/a flow in from the west, only 15 km3/a leave this largest freshwater swamp on Earth. The Blue Nile alone contributes 54 km3/a, most of which is collected by samll tributaries below lake Tana. Together with the Atbara (12 km3/a) and the Sobat (13.5 lm3/a) the Ethiopian mountains deliver 84% of the discharge availbale at Aswan.
Results of a sampling on reed (Phragmites australis) height performed in the edges of diverse water bodies of the Llobregat delta are shown. Sampling was carried out between October and December 2002, when reed shots of 2001 (dry) and... more
Results of a sampling on reed (Phragmites australis) height performed in the edges of diverse water bodies of the Llobregat delta are shown. Sampling was carried out between October and December 2002, when reed shots of 2001 (dry) and those of 2002 (green and recently fruited) coexisted. In each sampling point, height was measured in up to 25 fruiting shoots of 2001 still showing their fruiting panicle, and also in three shoots of 2002 adjacent to each 2001 shoot (tota- lling up to75 shoots). Shoot height of each year and differences between years in adjacents sho- ots were correlated, respectively, with measures of conductivity, and concentrations of total Phosphorus, phosphates, and nitrates (performed in the adjacent water bodies by municipal water control programmes) and with interanual differences in these measures. Results showed fair to non-significant correlations between reed heigh and water measures, but moderate to high nega- tive correlations between interanual variations of these variables. In conclusion, decreasing reed height can be considered a good indicator of increasing water salinity and eutrophication. Ecological and conservation implications of results are discussed.
Moushuni island is one of the island of Indian Sundarban, but changes of vegetation cover is occurred due to natural and anthropogenic activity. The aim of this paper is to emphasis the changes of vegetation cover between 2000 and 2020 of... more
Moushuni island is one of the island of Indian Sundarban, but changes of vegetation cover is occurred due to natural and anthropogenic activity. The aim of this paper is to emphasis the changes of vegetation cover between 2000 and 2020 of Moushuni island. Vegetation indices like Normalised Difference Vegetation Index (NDVI) is used to identify the changes of vegetation cover from 2000 to 2020. Based on NDVI value, the study area is classified into four classes-Dense vegetation, Sparse Vegetation(vegetated), No vegetation and Water. Result shows an overall increase of dense vegetation cover (8.1%) in the island. The percent of vegetated area coverage is decreased during the study period. The major cause of decrease vegetation may be attributed to increase of rural settlement and salinisation.