GEOSPATIAL ANALYSIS OF THE HYDROLOGICAL CHARACTERISTICS OF NABLUS MOUNTAIN WATERSHEDS IN PALESTINE

Abstract

Morphometric parameters are the mathematical visualizations of watershed
landforms that provide powerful insights into the hydrological processes that drive
and shape a watershed. This is especially true for climatically variable regions with
complex topographies such as in our study area in the Nablus Mountains. This
study aimed to identify the morphometric characteristics of the Nablus Mountains
and the spatial distribution of those characteristics. By using the 2008 ALOS
PALSAR Digital Elevation Model with a spatial resolution of 12.5 meters for surface
and hydrological analysis, eleven main watersheds were recognized and divided
into two main drainage systems, i.e. the Mediterranean Sea Drainage System
(MSDS) in the west and Dead Sea Drainage System (DSDS) in the east.
Morphometric characteristics analyses were performed across linear, areal and
relief aspects, resulting in 25 parameters. Drainage density (Dd), bifurcation ratio
(Rb), circularity ratio (Rc) and hypsometric analysis (Hs) values were the
parameters that most clearly differentiated between western and eastern
watersheds. Western watersheds were more elongated in shape, with dense
vegetation cover, steep sides and high annual rainfall amounts, and the
hypsometric integrals revealed them to be older than those in the east. In
contrast, watersheds in the east had high circularity ratio, low vegetation cover
and steep slopes, which indicated high susceptibility to flash floods and soil
erosion. Thus, soil conservation practices and rainwater harvesting techniques
would be better suited for the eastern watersheds and sub-watersheds in the
central part of the Nablus Mountains, where slopes are steep and rainfall amounts
are high.