In Iran with an arid and semi-arid climate, the optimal use of water resources is a necessity. Due to the increasing population on the one hand and the reduction of groundwater resources on the other hand, quantitative assessment and calculation of the water balance of catchments are of great importance. Water balance reports are one of the most prominent study projects in water resources management in the country. Despite the importance of these studies, there are some issues in the process of preparation of water balances that may lead to errors. The purpose of this study is to evaluate water catchment balance calculations and identify the factors that cause the most uncertainty and error in these calculations. In general, the estimation of the water balance will be reliable, by reducing accidental and systematic uncertainties. These improvements can be achieved through the creation of a reliable data bank and turning it into an effective tool for balance assessment, as well as creating an adequate hydrogeology and hydrology knowledge of the study area, sufficient knowledge of the boundary conditions, an appropriate spatial and temporal resolution of the area, and accurate calculation of the input components such as rainfall, recharge, evaporation, irrigation status, and infiltration coefficients, etc.

Snow is one of the main elements of hydrological cycle of the mountainous basins. In the basins, snow runoff plays the main role of the river flows. Although there are snowfalls in the eastern highlands of the country, the effect of this kind of hydrological element is different from the western areas. The goal of the study is to investigate on the effect of simulated runoff on the flowing water balance parameters in the BAAR NEYSHABOUR basin. To reach the goal, the counted discharge of ARIYE hydrometric station located on BAAR River is used and to count the rainfall, BAAR-ARIYE evaporation center is utilized. Counting term is about 30 years. Water years of 1975 to 1989 for simulating and calibration and the verification are happened from the years of 1995 to 2009. The consequences show that, despite the simplicity, WASMOD model is able to simulate the runoff even by low receiving data. So the mentioned model can be used in the basins with the low available data. The capability of the model was studied in two ways, and the results suggested that the model with the effect of snow is more related to the reality. Modeling is possible even with no regard to the snowfall. Basic runoff conduction under the effect of the snow is nonlinear as well.

The paper describes an extensive analysis of hydrometeorological information of Taleghan catchment in the north west of ternan province. Potential snowfall areas as well as advance and retrogression of snow line are identified using temperature data and hypsometric curve. Snow index together with snow-water volume of catchment then are determined. Finally snow melting mechanism of basin investigated using energy budget method and spring river discharge is forecasted by means of multiple regression method.

This study was based on the hypothesis that “Ecotourism is an important instrument in sustainable rural development and ecologically-based landscape planning approaches which take the objectives of socio-economic development and nature conservation have an effective role in this issue”. For this purpose, the necessity of ecologically-based landscape planning approaches in the planning and implementation of ecotourism activities and the importance of the views of related stakeholders in decision-making process have been established in this study. The field of study was grounded on subbasin and micro basin boundaries which take natural thresholds into consideration instead of administrative boundaries which contrast with natural thresholds. A total of 31 micro basins, consisting of 20 basins in the Kazandere basin of a total of 293 km² in the northwest of Turkey and 11 basin in the Pabuçdere basin, have been assessed. A 3-phased method was followed in the study. Firstly, the inventory and data base of the field were created on Geographic Information Systems medium and micro basins were determined. In the second phase, suitability analyses were carried out on the basis of the Ecotourism Opportunity Spectrum (ECOS) according to 6 basic components, 15 assessment factors, and 24 subcriteria.In the third phase, the micro basins suitable for ecotourism potential were determined by creating a synthesis sheet on the field of study as a result of related analyses and assessments, and ecotourism oriented development strategies were developed by utilizing the rapid rural appraisal conducted in the area and visitor questionnaires as well.

Actual evapotranspiration (ETa) is one of the major components in the hydrologic cycle and its accurate estimation is of paramount importance for many studies concerning hydrologic water balance and water resources planning and management. Evapotranspiration is a complex nonlinear phenomenon depending on several interacting climatological and crop factors. This paper determines the minimum climatic data required for estimating ETa in a representative catchment (Emame, Iran) using artificial neural networks (ANNs) technique. Four combinations of weather parameters were considered as input data and the resulting values of ETa were analysed and compared with those of water balance method. The study indicated that maximum and minimum air temperature, relative humidity, and wind speed are the minimum climatic data required for estimating ETa. With these input data, the root mean square error (RMSE) and the coefficient of determination (R2) for the comparison between observed and estimated ETa are 0.17 mm d-1 and 0.95, respectively. Plotting measured values of ETa versus predicted values suggests that 82 percent of the values lie within a scatter of ±15%.

In many floods controlling, watershed-management and water-resources projects, estimating of river flow-rate is important and needs a comprehensive hydrological modeling of flow-rate evaluation. Need for enlightening the status of water-resources and precipitation in different watersheds and the lack of networks of hydro-meteorological gauging stations, reveal the importance of estimating the runoff volume in watersheds. In addition, designing of hydrostructures on rivers such as bridges and weirs are in need of forecasting related floods of the territory. In this research explores discovering of the hydrological soil groups of Ab-Bakhsha watershed in Bardisr in Kerman province for evaluating the flood peak and volume. There is soil group data just for one sub-basin therefore; the watershed suffers from lack of hydrological soil group data. For that reason, slope maps evaluate the hydrological soil group which shows the 87% accordance with the available data. To continue, the HEC - HMS software modeled eight flood events using estimated data and rainfall-runoff observation. Four target-functions calibrated the model for curve number and coefficient K in Muskingum method. In the end, to evaluating the calibrated model, four flood events by NOF and EF goodness of fit tests were simulated. According to the results, the RMSE method as the best target-function used for optimizations. In general based on the lack of information about the soil curve number and promising results of this model, one can knows this method as a proper method for calculating the flood volume in preliminary study plans.

Low rainfall with improper temporal and spatial distribution is a significant problem in arid and semi-arid areas. Due to the lack of water resources and the increasing water demand, access to new water resources is necessary. Rainwater collection is one of the most prominent methods of rainwater exploitation management to deal with water shortage which is developing rapidly in many areas. Considering the diversity and breadth of rainwater collection methods, serious attention should be paid in choosing the influencing factors and the type of criteria combination method. In this article, in order to determine the places prone to the construction of rain catchment surfaces for livestock drinking, first the effective factors were determined with the studies conducted and the characteristics of the area.Seven factors were considered, including slope, land use, soil depth, distance from fault and waterway, proximity to livestock farming, and prevailing wind direction.The factors were ranked using the fuzzy logic technique.This involved dividing them into nine separate parts. A geographic information system was then used to overlap these layers. The results of this overlap were classified into five classes: poor, average, relatively good, good, and very good.The rainwater collection areas for each class were 44.01, 53.94, 30.31, 30.48 and 12.51 km², respectively. Also,Based on the results of fuzzy logic, the south and southeast part of the region had the first priority for the construction of rain catchment surfaces.Therefore, it can be used to collect rainwater and store it for future use.The findings of this research work will help policy makers and decision makers to implement different rainwater collection structures in the study area to overcome water shortage problems