TITLE:
The Contribution of the Geospatial Information to the Hydrological Modelling of a Watershed with Reservoirs: Case of Low Oum Er Rbiaa Basin (Morocco)
AUTHORS:
Youness Kharchaf, Hassan Rhinane, Abdelhadi Kaoukaya, Abdelhamid Fadil
KEYWORDS:
Modeling; Hydrology; Low Oum Er Rbiaa; Reservoirs; GIS; SWAT; ArcSWAT; Watershed
JOURNAL NAME:
Journal of Geographic Information System,
Vol.5 No.3,
June
19,
2013
ABSTRACT: Water is
undoubtedly the most vital natural resource. Water use management is one of the
greatest challenges that face humanity. The demand for water is continuously
growing because of the population growth, the intensive urbanization and the
development of industrial and agricultural activities. To face the increasing
pressure on this vital resource, it is so necessary to set up the adequate
instruments to ensure a rational and efficient management of this resource. In
this context, the hydrological modeling is largely used as an instrument to
assess the functioning of these resources at watershed scale. In addition, the
use of spatial models let to depict and simulate the watershed processes at
small spatial and heterogeneous scales that reflect the field reality more accurate
and more realistic as possible. However, the use of spatial models requires
geospatial data that must be gathered at very fine scales. The aim of this study is to highlight the contribution of geospatial data
to assess the hydrologic modeling of watershed by using a spatial
hydro-agricultural model, notably the SWAT model (Soil and water Assessment
Tool). The study area is the Basin of Low Oum Er Rbiaa River which extends from
the Al Massira dam to its outlet in the Atlantic Ocean.
This watershed includes a set of dams (Daourat, Imfout and Sidi Maachou) built
in waterfall fashion along the river. The objective was to simulate the hydrological functioning of this area
that had never been modeled in order to assess the management of these
reservoirs used essentially to produce electricity and fresh water. The implementation of the SWAT
model required a spatial database that was built from topography, soil, land
use and climate data. The calibration and validation of the model was carried
out on a daily basis over several years (2001-2010) using The ArcSWAT tool
integrated in ArcGIS software and the Parasol optimization method. The
calibration of SWAT model was successfully done with 0.6 as value of Nash coefficient
used commonly in hydrology to evaluate the model performance. The calibrated model was then used
to estimate the hydrological balance sheet of the Low Oum Er Rbiaa to model the
intermediate contribution of the three reservoirs situated in the watershed.