16.6.1.2 Stream Number (Nu)
According to Horton’s (1945) law, it states that
the “number of stream segments of each order
forms an inverse geometric sequence with order
number”. This geometric relationship has been
shown graphically in the form of line graph
where the values of these variables (stream order
Versus stream number and stream order Versus
stream length) are plotted (Figs. 16.6 and 16.7).
Spiti river basin has the highest number of firstorder streams among all the basins. The total
number of streams of all orders in Spiti, Tsarap
Chu and Parechu basins are 6497, 1277 and 871,
respectively.
16.6.1.3 Stream Length (Lu)
Stream length has been measured by the law
proposed by Horton (1945) for all three basins by
raster calculator in ArcGIS 10.1. The number of
streams of various orders in the basins has been
counted, and their lengths have been measured.
In all the three basins, the stream segments of
various orders vary considerably. The total
length of the stream of all orders of Spiti, Tsarap
Fig. 16.4 Drainage network of Spiti Valley. Source Computed from SRTM
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219
According to Horton’s (1945) law, it states that
the “number of stream segments of each order
forms an inverse geometric sequence with order
number”. This geometric relationship has been
shown graphically in the form of line graph
where the values of these variables (stream order
Versus stream number and stream order Versus
stream length) are plotted (Figs. 16.6 and 16.7).
Spiti river basin has the highest number of firstorder streams among all the basins. The total
number of streams of all orders in Spiti, Tsarap
Chu and Parechu basins are 6497, 1277 and 871,
respectively.
16.6.1.3 Stream Length (Lu)
Stream length has been measured by the law
proposed by Horton (1945) for all three basins by
raster calculator in ArcGIS 10.1. The number of
streams of various orders in the basins has been
counted, and their lengths have been measured.
In all the three basins, the stream segments of
various orders vary considerably. The total
length of the stream of all orders of Spiti, Tsarap
Fig. 16.4 Drainage network of Spiti Valley. Source Computed from SRTM
16 Remote Sensing and GIS-Based Morphometric Analysis …
219