رسائل ماجيستير
English
2017
Runoff estimation in Yatta area watersheds
Muath Abu Sadah , Mohammad Hashem Almanasra, عصام الخطيب
كلية الدراسات العليا-جامعة بيرزيت · فلسطين
Similar to many Palestinian communities, Yatta area located in the southern part of the
West Bank receives a limited quantity of water. The area has more than 70,000
inhabitants, more than 37,000 dunums of agricultural land planted with different types of
crops in addition to different commercial and industrial activities (Yatta municipality,
2015).
The general objective of this research is to estimate the potential amount of total direct
runoff from Yatta watersheds to be used in the agricultural lands and to evaluate its
impact on the socio-economic situation in the study area.
In this research, rainfall received on Yatta area including the amount and variation was
analyzed using statistical methods. When the standard deviation values of annual rainfall
data were examined, their values were found to be far away from the mean. This reflects
the variability of annual rainfall data during the long analysis period.
This research focused on estimating the potential amount of rainfall which could be
collected from watersheds within the boundary of the area to be used for enhancing the
agricultural lands in the area. The water would help improve crop yields, family income,
create jobs and stop the deterioration of the green cover of the city. For this reason, a
watershed model was developed using the WMS and the HEC-HMS applications.
Accordingly, the rainfall distribution, evapo-transpiration, and physical characteristics of
the watersheds were defined.
The watershed in Yatta area and the characteristics of this watershed was defined. WMS
model was used to define and delineate this watershed and divide it to five sub basins
using the Digital Elevation Model (DEM), land use, and soil type for Yatta area. Land
use and soil type were created using the Geographical Information System (GIS). The
boundary of Yatta watershed and its sub subbasins in addition to their physical properties
are saved and exported HEC-HMS. This model was used to simulate the watershed;
accordingly, two models were developed based on hourly rainfall data for Yatta area in
2014/2015 rainy season.
As a result, the runoff coefficient was estimated at (1.6 - 2.4) % which is considered very
low due to the low intensity of rainfall as well as its annual amount. The analysis
concluded that an average of 90,000 m3
/yr of storm water could be collected and stored in
earth pools and cisterns at different locations within the boundary of the watersheds. This
amount can be a supplementary source to irrigate around 300 dunums of olives, almond
and grape trees in addition to more than 60 dumuns of vegetables. Therefore, this study
proved that storm water can still be considered as a potential source of water which could
contribute to solving water problems and improving the socio-economic situation.
