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In the Small forest basins, mostly are the headwater of the Caspian sea basin, long historical data are unavailable, therefore physically bases model are suitable tools to evaluate them.The aim of this study was to simulate water balance components and estimate the impact of hydrogeological, morphological and hydrological conditions on water balance components in Kasilian representative basin. The BROOK90 model was applied and calibrated for the water balance analysis. Twenty years of hydro-climatology data were used for setting Brook90. Data from the period 1992–1993 was used for calibration, and the interval 2004–2006 was considered as the validation period. The calibration of Brook90 was done by trial and error. Visual inspection of the measured and simulated discharge curves and mean bias error were the indicators for model performance. The simulation results demonstrate that the model can give a fair estimation of the water balance components. The results of sensitivity analysis on model parameters indicates that geological, hydrological and land use factors play important roles in runoff generation and water balance components in the basin. The water balance investigation showed that about 76 percent of the annual precipitation released as evapotranspiration and 24 percent as streamflow. The average contribution of the individual streamflow component to total streamflow is 46.67% groundwater flow, 38.32% Source area flow, and 16.99% Bypass flow. The increase of vegetation cover reduces total evapotranspiration and total runoff that play an important role in reducing the potential of flooding and an increase in groundwater storage in the basin.

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The extended breadth, brilliant historical background and powerful ancient empires lead researchers to conclude that Iran must have been powerful enough in those eras in scientific domains especially in terms of geographical knowledge. But the remaining scientific works in geographical arena isn’t considerable enough. In the present study, using the literature review method, an attempt has been made to reveal few geographical references about Iran prior to the advent of Islam. These references are books, manuscripts, inscription and epopee forms. Among the books, the Avesta, Bundahišn, Dēnkart, and Menog-i Khrad have a significant importance. Moreover, Šahrestānīhā ī Ērānšahr, The wonder and remarkability of Sagastān, History of Karkā ḏe Bēṯ Selōḵ, The Chronicle of Arbela, Parthian Stations and Movses Khorenatsi are geography books that too discuss geographical issues of ancient Iran. The letters of ancient kings such as Ardashir-e Babakan, Tansar and Artabanus to Susa citizens also contain information about geography. Some inscriptions from ancient Iran have geographic concepts such as Darius, Persepolis, Susa, Xerxes I and Shapur I. There is a lack of geographers’ name in ancient Iran same as scientific references about geography. Only two people named Isidore Charax and Movses Khorenatsi could be found who studied the Iranian geography, directly.