MTech

Land degradation is a problem of grave concern and one major factor leading to
it is soil erosion. The main aim of the study is to calculate the soil loss in the sub
watershed. This study also analysed the quantitative analysis of morphometric
parameters of Kurumanpuzha sub watershed using remote sensing data and geographic
information system. Morphometric parameters were evaluated from three perspectives:
Linear, Areal and relief characteristics. A fifth-order river drains Kurumanpuzha
watershed and the drainage network is mainly dendritic type. The mean bifurcation ratio
(Rb) was 2.05. The watershed has elongated shape suggesting low peak flows for longer
duration and hence easier flood management. The drainage texture analysis revealed
fine drainage which implies the dominance of impermeable soft rock with low
resistance against erosion. High relief and steep slopes dominates, by which rough
landforms (hills, breaks, and low mountains) make up major portion of the watershed.
The hypsometric curve with hypsometric integral of 0.48 suggests that Kurumanpuzha
watershed is in equilibrium or mature stage of geomorphic evolution. At sub-watershed
scale, the derived morphometric parameters were grouped into three clusters (low,
moderate, and high) and considerable spatial variability was observed. The results of
this study provide information on drainage morphometry that can help better understand
the watershed characteristics and serve as a basis for improved planning, management,
and decision making to ensure sustainable use of watershed resources.
Soil erosion is caused by the action of various factors which are intrinsic to the
soil or related to the environment surrounding the soil. These factors include rainfall,
soil erodibility, topographic characteristics, crop cover and conservation practices. The
Revised universal soil loss equation (RUSLE) is a well-renowned empirical formula
which is used to compute the average annual soil loss of a particular area. Remote
sensing (RS) and geographical information system (GIS) technologies make modelling
and execution of RUSLE easy, reliable and cost effective. So, these were employed to
compute the spatial distribution of soil erosion risk area in Kurumanpuzha sub
watershed in Kerala state, India. All the factors were generated using metrological data,
CartoSat DEM, Landsat 8 imagery using GIS software and integrated in a GIS
environment to estimate the soil loss rate. It was found that forest/Dense vegetation
142
(56.46%) was the dominant land use followed by rubber plantation (20.06%) and o
scrub land (8.91%). The average annual soil loss of the watershed was estimated to be
8.00 t ha-1 yr-1
and the total quantity of soil eroded was 82,872.4 t yr-1
. The average
annual soil loss was highest in bare land (8.55 t ha-1 yr-1
) followed by scrub land (5.27 t
ha-1 yr-1
). The soil erosion map thus generated can serve as a basis for adopting suitable
measures in the watershed for sustainable management of the resources in it.