پژوهشنامه مدیریت حوزه آبخیز
سال ششم شماره 11 (پیاپی 12، بهار و تابستان 1394)

Two major issues through studies on hydrological impact assessment of climate change are the sufficiency of historical data and selection of the best rainfall-runoff model. Climate models، with the ability to simulate climatic variables، are considered as references for future projections. Therefore، the rainfall-runoff model must be able to simulate streamflow using only these variables. Current study addresses a methodology of choosing the best model from global climate models for impact assessments which require local-scale climate scenarios. The approach is based on the use of a weather generator which can generate the local-scale daily climate scenarios used as an input in many process-based impact models. The results of analysis of Sufichay streamflows، which flow in Urmia lake basin، by the rainfall-runoff model of IHACRES، indicated a considerable difference between the climate models under emission scenarios A2 for the future period 2046-65. There were no noticeable differences under emission scenarios B1 for both future periods (2011-30 and 2046-65) and under emission scenarios A2 for the near period (2011-30) especially in warm seasons. The uncertainty of selecting different emission scenarios was low for the period 2011-30 and high for the mid-century (2046-65).

Sediment load estimation is one of the most important issues in rivers & dam reservoirs management and generally in water projects. Various empirical equations show that proper analytical or empirical method is not suggested for correct estimation of suspended sediment, yet. In the present study, to assessment of closer estimation to actual data of transported sediment in Ghoran Talar station located in Babolroud River, the adaptive neuro-fuzzy inference system (ANFIS) technique is used as an Artificial Intelligence method. At first, various combinations of discharges based on time delay is considered as input parameters and the suspended sediment load is applied as output of the model. After Learning the network and assessment of the best structure according to type, number of membership function and related rules by use of MATLAB software, appropriate model is obtained based on statistical indices viz. mean square error, model efficiency and determination coefficient. As a result, one dimensional input according to Sugeno inference system with two triangular membership functions is introduced as an appropriate model and is compared with sediment rating curve values. Finally, the results showed that ANFIS method (MSE=0.08, EF=0.78, R2=0.72) has higher accuracy than sediment rating curve (MSE=0.16, EF=0.57, R2=0.73) and has better efficiency in suspended sediment load estimation.

Concern about the impact of climate change on natural and socioeconomic systems has been increased in recent years and this issue caused an increasing interest in the scientific community. The aim of this study is to evaluate changes in parameters such as precipitation, minimum and maximum temperature by General Circulation Models (GCM) and its impact on average runoff using SWAT model in Ghazaghli watershed in Golestan province. Initially, these parameters based on IPCC scenario A2 and B1 and using HadCM3 of general circulation models and for future periods 2030-2011 and 2099-2080 using LARS-WG weather generator in the synthetic was simulations and downs scaling. To investigate the basin hydrological response with changes in climate input data to the optimized SWAT rainfall - runoff model, after run model output of model was evaluated. The results showed that in the study area, the average minimum and maximum temperatures in both the period and the second period would increase under both scenarios. Rainfall increases in all months in the period 2030-2011 while in the period 2099-2080 the precipitation will increase in the cold season. Runoff analysis shows that under both scenarios A2 and B1 in the future compared to the baseline scenario (period 1995-1985) runoff between the 133.28_-26.66 percent will change to several month. Compare scenarios A2 and B1 show that B1 scenario compared to A2 scenario and 2099-2080 periods compared to 2030-2011 periods in the study area have critical condition.

The lack of enough meteorological stations at high elevations in mountainous regions causes a limitation for using regression relations to interpolate air temperatures at different time scales. Therefore, in this study, geostatistical methods include Kriging, Co-Kriging and Weighting moving average has been compared with elevation-temperature relation using a data series of 25 years (1975-2000). Evaluating the selected interpolation methods has been done based on Root Mean Square Error, Mean Absolute Error and Mean Biass Error. Also the physical conception of estimated values has been analyzed based on extracted maps. Results showed that using elevation as a covariate in Cokriging method caused a 28% increase in effective range. Although Kriging method overestimate the monthly and yearly air temperature, no significant difference was observed in evaluating indices between Kriging and Cokriging methods. Results also demonstrated that both Kriging and Cokriging method could be used instead of linear regression to interpolate air temperature in the study area. Analyzing prepared maps showed a decreasing pattern in air temperature from east to west parts.

Suspended sediment (SS) flux in a river is an important parameter for the watershed management. The large extend of watersheds areas and limited of sediment stations measurement have been caused that different methods have been developed to SS estimation. In this study, 42 sediment measurement stations existed in south and southeast of the Caspian Sea with over 20 year period was chosen. The sediment rating curve (SRC) was drawled using discharge and SS load measurements for 42 stations, then daily SS load was estimated by using the daily discharge (Q) and the average of annual SS was computed. By using the gamma test (GT), 14 effective variables on SS was reduced to 5 main variables and the mentioned stations were recognized in four homogeneous groups by using Andrew c urves (AC). For each homogeneous group and all existed stations using five selected main variables was developed regression models for average of annual SS load. Relative error (RE), r elative bias (RBIAS) and r oot relative mean squared error (RRMSE) indices statistics are used for evaluating the accuracy of the models. The results indicated that a model was not provided for group 1. The models of g roups 2 to 4 have a good accuracy and the model of g roup 4 with RE(29%), RBIAS(12%) and RRMSE(35%) in the calibration stage, and RE(19%), RBIAS(12%) and RRMSE(25%) in the validation stage has the best performance and One model for all stations has high error. Peak discharge with two return periods (Qp) has the most impact on the average of annual SS change.

Drought is known as an environmental phenomenon which leads to socio- economic and environmental issues. Therefore its analysis is crucial for proper management and planning of water resources. The Karkheh River basin is one of the important water resources in Iran and that is located in western Iran. Current paper tries to take one step ahead toward scientific and practical drought management in this basin through analyzing hydrological droughts. In this research, daily discharge time series from 13 hydrometric stations were used. The constant threshold level method was applied. Then dry periods were extracted and results were analyzed. The results showed that the largest volume and longest duration of drought in threshold level of 70% mostly happened after 1998. Finally, the suitable probability distribution for the annual maximum series of duration drought and deficit volume at each station was determined. The results revealed that the Johnson distribution is suitable for maximum deficit volume series at 38.5% of stations and the Johnson and Double exponential distributions are suitable for maximum duration series at 23% of stations. Based on the suitable probability distribution, return period of droughts were also computed and the possibility of drought predictions in future was determined.

Sustainable development is a comprehensive approach to improve Human life quality to meet economical, social and environmental needs of anthropological residents. When sustainable development is achieved an overlapping is created between ecological, economical and social classes. The most principle goal for this research is to determine sustainability criteria and indices and to measure sustainability. The first approach was obtained from, watershed and range management projects monitoring and evaluation monitoring instructions provided by president strategically supervising planning assistant and range and watershed management, forest organization for Iran. As a whole in rangeland ecological section, three criteria, nine indices and fourteen variables were evaluated. In economical and social issues section 5 criteria and 16 indices were evaluated (indices served as variables by themselves) in respect to total Zeidasht watershed score, this watershed is categorized in too poor sustainability class. The second method to analysis and evaluate sustainability in interested basin has been IUCN. This method simultaneously considers ecosystem and anthropological issues. Two criteria, six indices and 28 variables were measured in human welfare section. In ecosystems sustainability four criteria and ten indices and 35 variables were evaluated. Final indices and criteria integration was completed and map was developed in GIS. Final score for ecosystem and social and economical issues were 51 and 49 respectively. Final results the Barometer of Sustainability showed that Zeidasht 1 basin sustainability is moderate. This situation can be improved by ecosystem conservation and people life style quality enhancement.

In this research, an investigation on the changes of two major climatic parameters i. e., temperature and precipitation is done in the Mazandaran Province and west of Golestan Province with emphasi s on part of coastal line of Caspian Sea and its comparison with changes of these two parameters in scales of northern hemisphere and global. For this purpose, the time series of annual precipitation and mean, maximum and minimum temperature in three the Gorgan, Babolsar and Ramsar sites, were analyzed during statistical period of 1956-2005 and in five decades and also nine other sites with various statistical periods from 19 years to 36 years. In this research, used from non-parametric tests of Mann-Kendall and sen ׳ s estimator of slope to detect trend qualify and quantity respectively. Results indicates that Changes in mean of five decades than long mean and also relationship of temperature and precipitation changes in three sites of Gorgan, Babolsar and Ramsar is observed that with decrease in temperature, is seen a decrease in precipitation and with increase of temperature, an increase in precipitation is observed. This concept, only in five the 10-year periods is seen as separate and trend in these two parameters during the 50-year period is to the other form and in three stations is different; so that average temperature is increased and precipitation is decreased in Ramsar site and regional average, and in two Babolsar and Gorgan sites is observed increase and decrease of these two parameters respectively. Also in two global and northern hemisphere scales, is observed increase of average temperature and decrease of precipitation that take place opposite of each other and is similar to changes in these two parameters in Ramsar site and regional average. Also investigation of minimum and maximum temperature in these three stations, in general, showed stronger increase in minimum temperature than maximum temperature, and it can be in relation to increase in greenhouse gases that has more impact on increase of minimum temperature. Generally, increase in temperature is observed in all of case study sites with the exception of the Gorgan site and also precipitation in different sites has various changes that this condition can be result of increase in greenhouse gases in local, regional and global scal e s and also distance from voluminous reservoir of Caspian Sea.

In this study, Neuro-Fuzzy model was used to prepare the map of Vaz watershed landslide susceptibility in GIS environment. Location of landslides occurred in the study area was determined through interpretation of aerial photographs and the field monitoring. In the next step, factors affecting landslide occurrence such as altitude, lithology, slope, aspect, distance to drainage, distance to road, distance to fault, rainfall, and land use were digitized. Then, landslide susceptible areas were assessed by using ANFIS model based on factors affecting landslide occurrence. For this purpose, two membership functions of triangulate and Gaussian were used to prepare landslide susceptibility map and compare their results. Two statistical criteria of RMSE and MEE were employed to evaluate model performance. The results showed high efficiency of ANFIS model for preparing landslide susceptibility map and also the ANFIS model with Gaussian membership function over-performed the ANFIS model with Triangular membership function in the study area. Landslide hazard map showed that the regions with high risk have the most area indicating high risk-taking of Vaz watershed in occurrence of landslides.

Vegetation cover of Rangelands with have effective role in water reserve and soil conservation. Grazing by domesticated animals in rangelands protect desirable and palatable species and sustainable production in rangeland ecosystem. In order to investigation grazing effects on soil infiltrations and physical-chemical properties an experiment was conducted at three regions, consisted of reference, key and critical areas for this reason, rangelands part of Vaz watershed in Mazandaran province Iran. After field survey, three areas with different grazing intensity were determined and after study of vegetation cover, the experiment of water infiltration in soil carried out using of double ring method with suitable replications and then sampling of soil was done for measurement of some physical and chemical characteristics. For infiltration an infiltration apparatus based on kastiakov equation were used to determinacy cumulative infiltration and temporal mean, rate and time of final infiltrations. Finally, Results of three areas were compared together. Results of ANOVA showed that the amount of the mentioned traits were highest, lowest and intermediate at closed, critical and key areas, respectively. Results of soil factors also indicated that interaction effect between treatment and year had significant effect on bulk density (p≤ 0.01) and Ca and P (p≤ 0.05).

Watershed is a complex and dynamic system and is considered to be a planning and management unit. It is important to consider all technical, social, economic, physical, ecological and administrative dimensions in the process of planning and management of watersheds. Given the fact that there are complex interactions among these dimensions, implementing integrated watershed assessment and management is required to integrate these various disciplines. Usually stakeholders in a watershed deal with different information and decision choices that make it difficult for them to make a conclusive decision. Additionally, it is necessary to allow stakeholders to participate into decision making process and express their views across all stages of the process. Decision Support Systems (DSSs) as a computer-based tool box, assist stakeholders to reach their final informative decision. A DSS basically consists of models, database, and a user interface. This paper refers to a prototype DSS developed for the Chel-chai watershed in Golestan province using the Interactive Component Modeling System (ICMS) software. A user friendly interface has been developed for non-technical users to communicate with the DSS. This DSS is able to facilitate the integrated and participatory watershed management by improving the system understanding of stakeholders, introducing management activities in the form of different management scenarios, and predicting the various impacts of the scenarios graphically based on different indices (social acceptance, gross margin, variable costs, soil erosion, runoff volume, weighted mean patch size index, and weighted land cover area index). The management activities include terracing, orchard development, agroforestry, forage cultivation, and tree planting. Thus, through integrating different biophysical and socio-economic disciplines of watershed, the DSS developed in this research can assist stakeholders in the process of decision making.

Soil erosion is a serious issue in Iran. Determining the rate of soil erosion in various regions could help for better understanding of the erosion condition and soil conservation planning as well. In accordance with this constraint, more than 840 measured values derived from Cs-137 method and experimental plots in 31 research sites countrywide were collected, and analyzed related to different land uses, climates and slope classes. The existence of a few hundred times difference between cesium- 137 derived soil erosion and experimental plot's soil loss prevent us to combine these two sets of data. Comparison of the soil erosion and soil loss value in different land uses characterized the forest with minimum rate followed with ranges and dry farming respectively. Nevertheless, soil loss from poor ranges on marly formations was analyzed in a separate class due to nearly ten-fold differences with other ranges. Surface cover, tillage, and land sensitivity to the erosion are some factors that affect these differences. Comparison of two measured data sets in different climates indicated that the highest rates are generally matched to the Mediterranean climate. Lower soil loss in other regions could be related to the dense vegetation cover in humid area and low rainfall in arid climates correspondingly. Also, it is noted that apart from exceptional cases, the highest rate of soil erosion and soil loss are measured on gentle slopes between 1.5-12 percent which reduces by an increase in slope degree. The reduction of erosion rate in steeper slopes most probably relates to the abundance of surface gravel cover.

A great number of towns and villages are established along the rivers and especially on the terraces made by rivers. Under the influences of the river’s dynamic and discharge changes, these lands are constantly exposed to dangers such as the flood and instability of the river bed caused by the river meandering movements. Therefore, examining the meandering pattern of the rivers is necessary in order to prevent possible dangers. In this article, the study areas are Babolrud and Sajjadrud rivers in Mazandaran province in Iran which are situated on the coastal plains of Mazandaran. In this study, methodology was to use curvature coefficient (applied by Leopold and Wellman) and the central angle (cournice approach), as non-physical tools and topographical maps and aerial photographs were used as physical tools of the study. In the end, the results of the study showed that the average curvature coefficient within the area under study is equal to 2.46. This figure indicates that the ratio of the river’s meandering is high. It also shows that the rate of meandering river evolution is not the same regarding time and location. On the other hand, with regard to the obtained results of the index of curvature coefficient, 71.6 percent of the curves of this river fall into the category of evolved meandering pattern. The coefficients obtained from these models, necessitate the medium-term and long-term stabilization of the river bed, using management approaches and structural engineering.

Because of urban rapid growth of Iran, some problems such as propagation of environmental pollutions, urban inundation and flood hazards due to lack of appropriate drainage systems and irregularity of conduits & streams are the major difficulties in urban watersheds. Because of hydrological & hydraulic processes complexities in urban area, using of computer models would be effective. In this study, EPA-SWMM model applied for quantitative simulation of flash flood in some parts of Babolsar urban watershed.12 hour's simulation was done for 2 hours design storm with 2, 5 and 10 years return periods. Quantities simulation results shows that among the 259 junctions in the drainage network of study area, 32, 57 and 60 junctions for 2, 5 and 10 years return periods were inundated respectively. Peak discharges for 10 junctions of study area drainage network, estimated by rational method compared with simulated ones shows good linear correlation. Field investigations, Elevation maps of conduits and conducted simulation implies that the main reasons of inundation are small cross section area of conduits and also low bed slope & invert slope in some places. Conformity of flooded junction's simulation results due to rainfall with historical events in study area verifies the model simulations.

Determination of land capability for optimal use of land to prevent land degradation and improper use of lands is an effective step towards sustainable development strategy. Regarding the importance of subject, in this study in first; ecological potential for usual land uses in Iran (forestry, ecotourism, agriculture, range management, residential areas development and conservation) in Babolrood basin was evaluated using Analytical Hierarchy Process (AHP) and Geographic Information System (GIS). Then land uses were ranked using MOLA technique and land use planning map of study area was created. The results showed that 59.49 percent of the area was allocated to forestry and 21.82, 17.73, 0.05, 0.106 and 0.804 percent of the area were allocated to ecotourism, agriculture, range management, residential areas development and conservation respectively.