Page 73 - AJWEP-v22i2

Flood risk assessment of Barak river valley

Figure 2. The methodological flowchart
Abbreviations: AUC: Area under the curve; GIS: Geographic Information System; NDVI: Normalized difference
vegetation index; NDWI: Normalized difference water index.

was first introduced by Stefan-Boltzmann, with where e is the entropy value. The coefficient k is
j
Shannon formalizing the numerical induction in 1948. determined by the sample size (number of evaluating
Shannon later expanded the model into information objects), m, using Equation III.
theory, building upon the Boltzmann theorem. The
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entropy model is extensively applied for risk and k = 1 (III)
hazard assessments to calculate weighted indices of ln m
natural hazards and prioritize influencing factors. The information utility value for each indicator h is
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The entropy weights of all indicators and the final derived from Equation IV. j
susceptibility were determined using the following
equations. Entropy weights were calculated for all h = 1- e j (IV)
j
indicators, and subsequent susceptibility zone maps
were created using the following procedures and (iii) Step 3: Calculate the entropy weight of each
formulas. indicator using Equation V.
(i) Step 1: Normalize the value of each indicator to h
calculate index weight using Equation I. w = n j h (V)
j
X j1 j
y ij 0 , y 1 (I)
ij
ij
m X ij where is the weight of the th indicators, and n is
j
i0
the number of attribute indicators.
where, y is the specific gravity value for each X ,
ij
ij
and m is the number of evaluation objects. � X is derived (iv) Step 4: Define the flood susceptibility mapping
using Equation VI.
ij
from the FR value, and i represents a class of j flood
conditioning factor. n
(ii) Step 2: Define entropy for each indicator j using FSI = wNor F� j j (VI)
Equation II. j1�
where FSI is the degree of flood susceptibility index,
m
e y (II) w stands for the weight of each indicator and NorF
j = - k y ln ij j j
ij
i1 is the normalized rate for each flood indicator.

Volume 22 Issue 2 (2025) 67 doi: 10.36922/AJWEP025040019