Appraisal Of The Water Quality Of The Blue Nile, The White Nile And The Main River Nile For Irrigation Use

Abstract

The study was undertaken in Khartoum State, which lies between latitudes 15° 8` - 16° 39` N and longitudes 31° 36` - 34° 25` E, in the semi – desert tropics. Water samples were collected from the River Nile at Shambat bridge, the White Nile at Fetaehab bridge and the Blue Nile at Mak-Nimir bridge. They were obtained at the same day of each month for one year from March – 2008 to February – 2009. The objective of the study was the estimation of the water quality indices for the three Niles and appraisal of the water quality of the River Nile and its two main tributaries for irrigation use. The measurements of water quality parameters (pH, ECW, Na+, K+, Ca+2, Mg+2, Cl-, CO3 -2, HCO3 -, SO4 -2 ) were carried out. The USSL (1954) classification system revealed that the three Niles water salinity, as represented by ECW and SAR ranged from C1 – S1 (low salinity – low sodicity) class to C2 – S1 (medium salinity – low sodicity) class. Eight percent of the Blue Nile water samples belonged to the C1 – S1 class and 92 % belonged to C2 – S1 class. Sixty seven percent of the White Nile water samples belonged to the C1 – S1 class and 33 % belonged to C2 – S1 class. Fifty eight percent of the River Nile water samples belonged to C1 – S1 class and 42 % belonged to C2 – S1 class. Ca-Mg was the dominant cation class and Cl=CO3 was the dominant anion class. All water samples of the River Nile and its two tributaries gave low sodium hazard for the twelve months. The RSC values for all water samples, in all months, were negative indicating absence of carbonate hazard. The Langelier saturation index values for 83% of the water samples of the River Nile and its two tributaries were negative indicating dissolution of carbonate from water. All these results indicate that the River Nile and its two tributaries have good quality water for irrigation.