Development of ravine vulnerability index for identifying potential
zones of reclamation in ravine lands of Western India
Abstract
The ravine is considered as the worst manifestation of land degradation
by water erosion throughout the globe. About 120.7 M ha land in India,
suffers from various forms of land degradation, out of which 3.67 M ha
of land is affected by ravine. The extending ravine into the nearby 50 m
of buffer zone tends to deprive the farmers of their occupations forcing
them to work as landless laborers for their livelihood. Ravine
reclamation is a cost intensive activity, due to which it is financially
not feasible to go for reclamation in the entire ravine lands,
simultaneously. Therefore, there is a need to identify the potential
zones of reclamation for planning of reclamation work in a phased
manner. In this study, an innovative hybrid approach was used for
development of ravine vulnerability index for Mahi ravine in Western
India. The potential zones or active sites in the 50 m buffer zone of
the delineated ravine covering an area of 63031 ha was identified for
reclamation works. The spatial database was used for preparation of
raster layers using Arc GIS 10.3 software. The sand, silt, clay, organic
carbon, soil erodibility factor, slope, stream power index, topographic
wetness index, sediment transport index and cover factor were identified
as important parameter for development of ravine vulnerability index.
The weights were assigned to different parameters in pairwise comparison
on the scale of 1 to 10, based on the relative importance of the each
parameter with respect to another in the decision matrix of analytical
hierarchical process. The number of iterations were made to obtain the
consistency ratio less than 10% to obtain the final priority weights of
each parameter. The priority weights obtained for each layer was then
assigned in the raster calculator in the Arc GIS interface. The highest
weight of 28.5 was obtained for sand parameter and minimum weight of 1.4
for sediment transport index parameter. The ravine vulnerability index
validated through ground truth shows that 16703 ha (26.50%) area of
Mahi ravine in Western India was found be under very high priority and
was identified as potential zones or active sites for reclamation. The
land capability classification for reclamation of the Mahi ravine in
Western India shows that 20275 ha (32.16%) area of arable land falls
under Class-III followed by 18687 ha (29.65%) of non-arable land under
Class-VI for suitable soil and water conservation measures.