ABSTRACT An applied hydrological models were performed to model the rainfall-runoff relationship for Upper Adhaim River Basin. Three lumped integral models (hydrologic models) based upon the concept of the unit hydrograph were applied to analyze the rainfall-runoff relationship on a daily basis. These models are: the Simple Linear Model (SLM), the Linear Variable Gain Factor Model (LVGFM), and the Non-Linear Model (NLM). Five performance evaluation criteria have been used in this study. The application results of the (SLM) model showed a weak rainfall-runoff relationship. It was demonstrated that the linear assumption is valid only for the first four antecedent days. A considerable non-linear rainfall-runoff relationship was clearly observed from the results of (LVGFM) and the (NLM) models. Both models were satisfactorily identified at system memory of (17) antecedent days. However, the (LVGFM) was slightly superior to the (NLM). The (LVGFM) identified at system memory of seventeen antecedent days was used to simulate runoff flows. The simulation results show an acceptable applicability for the (LVGFM) in terms of simulating runoff events in time of its occurrence and volumetric fitness. The water budget for Upper Adhaim River Basin showed that an average of 73.4% from annual rainfall was evapotranspired, 8.0% was infiltrated and 18.6% was observed as direct runoff.
Estimation of runoff in an ungauged watershed is a significant part in the process of the water resources management. In the Iraqi western desert, the accessibility reliable surface runoff knowledge is scarce, that affects a critical difficulty for the hydrologic engineers. Estimation of surface runoff quantity in valleys of interrupted flow is significant to mobilize the deficiency water resources and manage valleys flow accurately. The incorporation of the Soil Conservation Service Curve Number (SCS-CN) approach with the geographic information system (GIS) was applied for estimating runoff volume of Wadi Hijlan, Fahamy, and Zgadan. The amount of runoff of the maximum storm were 7388700 m3, 12750000 m3 and 9851590 m3 for Hijlan, Fahamy and Zgadan respectively. In addition, the results showed acquired via the SCS-CN technique, revealed that the runoff depth fluctuated from 12.5 mm to 20.3 mm for (48mm) the maximum storm of rainfall through 2018-2019. The present strategy can be used for planning and development other valleys in the western desert of Iraq.
The management of water resources requires adequate information on the quantities of water supplied from the basins that outfall into a river, especially during the flood seasons. The study area located in the western part of Iraq within the administrative boundaries of the Heet district about 70 km from Haditha Dam, 45km from Ramadi in Anbar province. The study aims to evaluate the amount of surface runoff through a long-term period (1981-2019). Soil and Water Assessment Tool (SWAT) related to Geographic Information System (ArcGIS) was used for the simulation. The input data was the Digital Elevation Model (DEM) of SRTM with resolution 30m, land use/land cover map from the European Space Agency (ESA) with resolution 300m and, soil map from the Food and Agriculture Organization (FAO). The weather data used in the study were obtained from the Climate Forecast System Reanalysis (CFSR) combined with the weather data from the Surface meteorology and Solar Energy (SSE) produced by NASA. These weather data prepared using SWAT weather database software to be ready for the simulation processes. Al-Mohammedi valley was calibrated and validated using SWAT-CUP software using the available recorded discharges at Heet, Ramadi, and Al-Warar gauge stations. The calibration is based on the meteorological data for the period January 1, 2002, to December 31, 2006, and the validation was based on the data between January 1, 2007, to December 31, 2009. The model calibration and validation results based on two objective functions “Nash-Sutcliffe (NS) and coefficient of determination(R2)” showed that SWAT was successfully simulated Al-Mohammedi valley with NS = 0.72 and R2 = 0.76 for calibration, and NS = 0.63 and R2 = 0.65 for validation. According to SWAT results, the average runoff volume in the long-term period of simulation from January 1, 1981, to October 31, 2019, was 79.2 million m3 while the average runoff depth was 18.25 mm with about 17 % of rainfall becomes surface runoff.
The look for the new water resources and the optimal using of available water is very important because of high change in the climate of the earth, the dry wave in the region as well as the decreases of the water inflow to the Euphrates and the tigress river because of the building of the dams upstream the basin in Turkey and Syria. In the present study, four biggest catchments area in the Iraqi western desert (wadi Horan, wadi AlGhadaf, wadi Ubayiad, wadi Tubul) were selected to study the hydrologic properties to determine the best region for the water harvesting because these areas include the most water harvesting project such as the small dams. Present hydrologic study was depended on the available data to determine the amount of runoff that can be harvested according to measuring data of metrological station in the region with the method of hydrograph for analysis. For the period (1971-1976) the study showed wadi Al-ghdaf is the best region for water harvesting according to the number of floods to the cathment area (44 floods) with water volume (1047*106m3), and the average water harvesting (7098.64 m3/km2). The second is wadi Horan the number of floods to the cathment area (33 floods) with water volume (2033.29*106m3), and the average water harvesting (6115.16 m3/km2). Then wadi al Ubyaid number of floods to the cathment area (21 floods) with water volume (405.197*106m3) and the average water harvesting (2493.52 m3/km2). The last one is wadi Tubul with number of floods to the cathment area (18 floods) with water volume (909.36 and the average water harvesting (2231.6 m3/km2)*106m3)