Using Stream Length-Gradient Index (SL Index) in the Morphological study of the Smaqooli valley Basin

  • Ahmed Yaseen Ali Geography Department -University of Koya
  • Tahseen Abdulrahim Azeez Geography Department / Salahaddin University-Erbill
  • Hikmat Abdulaaziz Hamad Geography Department -University of Koya


 The aim of this study is to determine the influence area by the recent tectonic activities along the Smaqooli valley and it is tributaries using stream length – gradient index (SL). The longitudinal section and the necessary measurements of the index for main Smaqooli valley and it is 24 tributaries measured depending on 20 m interval contour map. The (SL) value of the sections is been extracted for the main section and it is (451) minor streams. Although the total value of the main stream. And the abnormal points have emerged by dividing minor streams value by the main stream value.

The investigation showed (351) Knick Point along the stream profile which their value exceeded number (2). Were (302) points of them was from the type 2 and (49) Knick Point of them were of the first type those which their (SL) values are more than (10). Which accounted a rate of (77, 65%) of total accounted points, and that was a big proportion and surly supported the recent tectonic activity in the basin. And it turned out that the second types of abnormal points have been distributed geographically on all of the minor valleys without taking any certain pattern, on contrary the first type points are distributed on two main ranges, which they are the northwest and the southeastern ranges. The longitudinal section of Smaqooli valley main stream and it is minor tributaries shows many renewed points and convex portions which reflected the roe of tectonic agents on them.  

Keywords: tectonic activity, stream- length gradient index, longitudinal section.


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How to Cite
Ali A, Azeez T, Hamad H. Using Stream Length-Gradient Index (SL Index) in the Morphological study of the Smaqooli valley Basin. JAHS [Internet]. 8Mar.2017 [cited 28Nov.2020];21(1):1-9. Available from: