Osman, A.R. 
GEOMORPHOLOGY OF THE BLUE NILE BY REMORE SENSING 
By: Dr. Osman A.R. Osman 
National Center for Research, Sudan 
Remote Sensing Authority 
Fax: 249 11 770701 , 773771 
E-mail: osman_osman@hotmail.com 
  
Paper number 1670 
KEY WORDS: Meander, Sinuosity Index, Remote Sensing, Blue Nile 
ABSTRACT 
The main objective of this study is to prove that remote sensing is a very efficient tool to map vast and remote areas; the 
second objective is to prove the Blue Nile is a meandering river of different ages. 
Geomorphologic interpretation on aerial photographs can be direct interpretation because of the visibility of objects i.e. 
landform. On the satellite image one has to use other criteria for the identification of the landforms this is generally less 
deduction involved than on most other kinds of interpretation and a high degree of reliability my thus be obtained. 
The sinuosity index (SI) has been used in our study of the Blue Nile on the Central Clay Plain using remote sensing 
interpretation. 
SI — Talweg Length 
Valley Length 
SI — Length of channel 
Length of Meander Belt Axis 
This study has been focused particularly upon meander geometry of the Blue Nile in Sudan. Geomorphologically the 
mapped Blue Nile in the study had been classified to three different stages. 
i. The old stage. 
ii. The mature stage. 
iii. The young stage. 
Rivers are dynamic and increasingly important part of the physical environment. Their behavior is of interest to a wide 
variety of concerns. They are essentially agents of erosion and transportation. 
1. INTRODUCTION: 
The mapping of the Blue Nile and palaeochannels was performed upon a mosaic of two satellite images, row 50 path 
185 and row 50 path 186 of dec. 1975. It is starting from about 20Km north of Sinnar dam in the south east to about 
10Km north of El Messed town in the north part of the study area. This Nile system could be considered as consequent 
stream with some subsequent streams like Dinder and Rahad rivers, which are coming from the same source joining the 
Blue Nile from the eastern bank. 
Geomorphologically the mapped Blue Nile could be classified as a meandering river of three different ages. The old 
stage from the Southeastern part of the study area (A), the mature stage in between (B) and the young stage at the 
northern part of the study area (C). See (Fig.(1)). 
2. OBJECTIVES: 
e To prove that remote sensing is an efficient tool to map the palaeochannels of the rivers by it synoptic view. 
e To map the palaeochannels of the Blue Nile on the Gazira area where it is now covered by dense cultivation. 
e To prove that the Blue Nile is a meandering channel of three different ages. 
  
  
International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000. 1089