مجله تحقیقات منابع آب ایران
سال شانزدهم شماره 2 (پیاپی 53، تابستان 1399)

A system dynamic model is necessary to estimate the existing interactions between Urmia Lake and factors affecting it. In this study, the Predator-Prey model using system dynamics simulation has been developed for Urmia Lake Basin. The main advantage of this model is providing the balanced water allocation between stakeholders in order to have a sustainable water management system for the lake. Due to increasing the area of irrigated lands in the northwest of Iran, having an applicable and up-to-date method to reduce water consumption in agricultural part is unavoidable. A stock-flow model has been designed in this study, in which Urmia Lake and irrigated lands are considered as the prey and predator, respectively. Then, the effects of various factors on the water elevation fluctuations of the lake have been analyzed dynamically and the strategies for reducing the water consumption of agricultural part have been investigated carefully. The results of this study indicate that the reducing irrigated lands by 40%, improve irrigation efficiency by 21% and reducing the area of lake by 20% lead to increasing water level of the lake by 1.7, 0.8 and 0.5 meters, respectively. By applying these policies, the water level of the lake will increase about 4.3 meters and it will lead to better ecological condition.

In recent decades, water level of the Hoor-Al-Azim/Hawizeh wetland (located on border of Iran- Iraq) as Shared resources has reduced sharply. In shared watersheds, interactions between riparian countries of a water resource system can be considered by a system dynamic model. The proposed model simulated the interactions among water resource systems of Iran, Iraq and Turkey without interactions of Socio-economic subsystem over the period of 2004–2016, which can be used to analyze various scenarios in the shared basin of Hoor-Al-Azim/Hawizeh. In addition, this study has developed a system dynamics model for several decision makers with different interests, based on integrated watershed. The model was validated for extreme conditions and the results showed well-calibration of the developed model to reconstruct the behavior of different parameters within the system. The results also showed that Tigris inflow to Iraq from Turkey has been decreased significantly during the simulation period. Subsequently, the inflow to the Hoor-Al-Azim/ Hawizeh wetland during the simulation period had been 61% less than the environmental flow averagely. Moreover, the model results for two scenarios of GAP project completion and 10% reduction in cultivated area of the three countries showed that wetland inflow decreases to 400 MCM and increases to 1900 MCM, respectively. In general, the proposed model can be used as support tool to evaluate decisions of policy-makers in the region. Thereupon, results of model for different scenarios indicate that improvement of environmental conditions would be approached by management alternatives based on integration of basin

In this paper, the SWAT model is used to study the effects of climate change on discharge and water quality of inflow of Esteghlal reservoir in Minab catchment. Climate change scenarios (RCP2.6, RCP4.5, RCP6, and RCP8.5) in 5 GCMs (GFDL-ESM2M, HadGEM2-ES, IPSL-CM5A-LR, MIROC, NoerESM1-M) to simulate future discharge, NO3 load, and agricultural products yield, were applied. According to the analysis of different climate change scenarios, the highest average annual precipitation decrease and increase were 34.8% and 37.2% in RCP8.5 and RCP6 scenarios in NoRESM1-M model, respectively. In the baseline period, the share of precipitation in winter is 65.8%, spring 5.1%, summer 1.8% and fall 27.4%. Crop yield change depends on the type of crop and its irrigation period. Because of the 77% water requirement of lima bean crop in winter, the average yield of this crop increases by 19%, as models show that the share of precipitation in winter increases by 9%. Also, 75% of water requirement of wheat and 44% of water requirement of eggplant is in autumn and winter that increased and stabilized rainfall in these seasons caused slight variations in yield. In contrast, 80%of water requirement of corn crop is in summer, and due to the severe decrease in precipitation in summer (15%), corn yield has decreased by 17%.

Quantifying the uncertainty contribution of important factors on the performance of rainfall-runoff models has always been one of the major challenges for researchers and hydrologists. The main problems of applying these models especially in calibration period are the large number of required parameters and the lack of physical understanding for some of them. This research addressed the uncertainty contribution of different infiltration methods (Green-Ampt, SCS-CN, Exponential, Smith-Parlange, Initial-Constant and Deficit-Constant) on the performance of HEC-HMS model using GLUE algorithm. Results showed that using each of infiltration methods imposes different uncertainty bounds on the simulated flood hydrograph by HEC-HMS. Findings indicate that SCS-CN and Smith-Parlange owing to have the higher P-factor (0.78 and 0.72) and lower ARIL (0.39 and 0.40) values, enforce minimum uncertainty on the model output. In addition, the mentioned infiltration methods have the fewer sensitive parameters and then performs better than other methods. In contrast, the uncertainty of applying Initial-Constant and Deficit-Constant methods for simulation of flood hydrograph is relatively high the smaller percentage of the observed data are within the 95% uncertainty bandwidth. Moreover, sensitivity analysis of the parameters of each of the infiltration methods using the nonparametric Kolmogorov–Smirnov (D) test showed that parameters with the sharp and peaked distributions indicate well-identifiable parameters, while flat and spread distributions indicate uncertain parameters. Overall, the outcomes of this study prove that GLUE algorithm has high ability to determine the optimal range of rainfall-runoff model parameters and the prediction uncertainty bandwidth.

Detection of pollution in any water distribution network (WDN) is essential to maintain public health. Recent researches have demonstrated common water quality indicators (free Chlorine, pH, Electrical‎ Conductivity, …) response to contaminants, which can facilitate the pollutant detection in WDNs. In this research, EPANET-MSX model is used to simulate the realistic responses of common water quality parameters to a pollutant event in WDN, represented in example 3 of EPANET 2.0. The aim of the study is to apply EPANET-MSX to trace Chlorine changes in response to the potassium cyanide injection order to optimize sensor placements WDN. Optimal sensor placement is derived based on coupled EPANET-MSX _ PSO (particle swarm optimization) framework. PSO is implemented as single and multi-objective algorithm. The objectives of the study are to reduce the pollutant detection time, increase detection likelihood, and reduce the contaminated water consumption as single and/or multi-objective problems. Studies on the sensor numbers, ranging from one to five, indicate 1- the pollutant detection time has decreased from 36.22 to 17.41 hours, 2- the pollutant detection likelihood has increased from 28.8% to 68.6%, and 3- the contaminated water consumption has decreased from 31.87 to 3.78 m3. The results show direct relationship between 1- pollutant detection likelihood and detection time, 2- pollutant detection likelihood and contaminated water consumptions, and 3- pollutant detection time and contaminated water consumption in multi-objective problems. Also, the location of the high-demand nodes in WDN and the contamination events occurrence can affect the location of the sensors.

If the channel network map of a region is not suitable for the purpose of modeling water and solute transport processes, the underlying river network should be extracted by the relating algorithms given the critical area as the input. The goal of this study was to (1) extract the critical area in the second and third order river basins in Iran, and (2) investigate the relationship between the critical area and physio-climatic characteristics of the basins with the aim of determining the most dominant factors controlling the critical area. To this end, the closest critical area to reality was determined by minimizing the difference between the drainage density of the extracted river networks using the D8 method and the one known as the base map of the river networks. Results indicate that the spatial resolution of the digital elevation model between 30 m to 200 m does not impose significant impact on the magnitude of the estimated critical area. Also, direct relationship holds between the critical area and the soil permeability and erosion rate, while the correlation is negative between the critical area and the vegetation density. Critical area is smaller and larger in the temperate and warmer climates, respectively. Furthermore, increase in the average slope and the average annual precipitation height decreases the critical area. Nevertheless, the correlation between the critical area and the studied physio-climatic quantities is insignificant, highlighting the need to determine the critical area of a given river basin using approaches other than physical-mathematical relationships.

Proper functioning of a sewage collection network whole depends heavily on its management plan. Prioritizing component inspection of these networks is also an important part of management plan and paying attention to it can greatly improve their performance. In the present study, after determining the factors affecting the structural deterioration process of sewers, the impact of each of these factors on their decision-making and inspection prioritization process is investigated. After defining the indices and determining how each index is scored, each of the indices is classified in the range of 1 (very good) to 5 (very bad). Subsequently, a deterioration model based on polynomial logistic regression was developed to estimate the structural status of components using defined structural indices and videometric data. In addition, hydraulic and environmental assessment indices of sewers were introduced, which classified the condition of sewers in the range of 1 (very good) to 5 (very bad). Finally structural, hydraulic and environmental indices are combined according to different scenarios proposed to prioritize for inspection activities. In the present study, a part of Tehran wastewater collection network was investigated. On average in all defined scenarios, the pipes are in excellent, good, average, bad and very bad condition with 0.2, 6.4, 44.1, 45.9 and 3.3% of the total length of pipes, respectively. According to the results of the sensitivity analysis on the index coefficients, the structural index was identified as the most effective index in the prioritization program and its precise determination should be considered.

Parameters uncertainty of rainfall-runoff models are the main sources of uncertainty in real time flood forecasting. In this paper, the Monte Carlo method is used to estimate the uncertainty of the forecasted flood hydrograph due to uncertainty in the calibration parameters of the rainfall-runoff model in Dez Basin in southwestern Iran. Precipitation and air temperature were predicted using Weather Research and Forecasting (WRF) model. The HEC-HMS hydrological model was used to forecast the flood hydrograph corresponding to the predicted precipitation and air temperature. The SCS-CN, Clark Unit Hydrograph, and Muskingum-Cung methods were used to model losses, transform and flood routing, respectively. The results show that the best scheme in WRF model is MYJLG to predict hourly precipitation and air temperature in Dez Basin. Therefore, the MYJ boundary layer scheme, Lin cloud microphysics scheme and GODDARD radiant scheme have the best performance in flood forecasting in Dez basin. In addition, the results of this study show that considering the simultaneous uncertainty in all parameters, the uncertainty in peak discharge of the forecasted flood hydrograph is higher than the uncertainty in the volume of the hydrograph. So that the uncertainty in peak discharge and the volume of forecasted flood hydrograph due to the uncertainty of all parameters are equal to 32.5 and 21.2%, respectively. Thus, with the lack of flood forecasting and warning based on risk, quantifying uncertainty has provided additional information about forecasts that will help decision makers make better decisions.

River flow prediction is one of the key issues in the management and planning of water resources, in particular the adoption of proper decisions in the event of floods and droughts. To predict the flow rate of rivers, various approaches have been introduced in hydrology, the most important of which are the intelligent models. In this study, a hybrid artificial flora- support vector machine model was applied to estimate the discharge of Dez Basin based on the daily discharge statistics provided by the hydrometric stations located at the upstream of the dam during the statistical period (2008-2018) and its performance was compared with the wavelet-support vector machine model. The correlation coefficients, root mean square error, and mean absolute error was used for evaluation and a comparison of the performance of models. The results showed that the hybrid structures presented acceptable outcomes in the modeling of river discharge. A comparison of models also showed that the hybrid model correlation coefficient (R= 0.933-0.985), root-mean-square error (RMSE = 0.008-0.088 m3/s), mean absolute error (MAE=0.008-0.088 m3/s) and the Nash–Sutcliffe coefficient (NS=0.951-0.995) has had better performance in estimating the flow. The results of the study of the charts disclosed that the suggested hybrid model has a suitable performance in estimating the minimum and maximum points and has fewer error in all selected stations.

Hydrological drought is a phenomenon that occurs due to the reduction of surface water and groundwater resources supply. Because of the dependence of the agricultural sector to soil moisture storage, it primarily affects this sector. Therefore, the analysis of the effects of this phenomenon is important for the better management and planning of water resources available in the agricultural sector. Theeffects of hydrological drought arising from reducing the supply of water resources on agricultural situation, water consumptions and farmers' gross profit in Tehran province were evaluated. For this purpose from Multi Period Positive Mathematical Programming and statistical information related to period 2013-2018 wereused. The results showed that the current cropping pattern in Tehran province is not optimal and with occurrence of hydrological drought, farmers’ tend decreases for the water-full crops such as watermelon, tomato and sunflower. In addition, the results showed that in the hydrological drought conditions, about 9.13 percent of agricultural water demand in Tehran province will not provided. This will change the pattern of cultivation inthe region. Reduction in the farmers' gross margin amunt 7.28 percent and increase in the economic value of irrigation water amunt 38.2 percent compared to the base period are other consequences the occurrence of hydrological drought in Tehran province. Overall, the results indicate that with the occurrence of drought, the cropping pattern toward products with lower water requirements and higher profits, but for tomato and corn products (despite the high water requirement) due to integrated farming in region reducing acreage is less visible.

The main objective of this research is evaluating IDF curves variation in the future using the observed rainfall and the forecasted one by PRECIS, while focused on yielding the uncertainties of the forecast via employing the K-NN WG model under two historical and wet scenarios. The historical climate change scenario and the B2 emission scenario were used to generate the lower and upper-reliability bounds of the forecast, respectively. By applying the shuffling and perturbation mechanisms, those random data, which are not recorded in the observing period but will be probably happened in the future, were generated and the results were employed for developing the IDF curves of 2, 5, 10, 20, 50, and 100-year return periods. Comparing the two climate change scenarios and the base period IDFs reveal the increase in the intensity of the extreme short-duration rainfalls. Moreover, it was found that the maximum amount of rainfall for the duration of 10 minutes to 3 hours on average would have a difference of 26 to 31 percent under the historical and wet scenarios concerning the base period, respectively. This difference between the historical and wet scenario is limited to 4.8%. The small difference between the historical scenario, as the lower bound, and the wet one, as the upper bound of the probable storms in the future, firstly shows the accuracy of PRECIS in simulating rainfall in the study region; secondly, it shows the certain increase in the intensity of the design storms which matter in urban flood management.

External source of weather signals is also called teleconnections that can change weather conditions and thus affect groundwater resources. The purpose of this study is to predict the effect of teleconnection patterns on groundwater level fluctuations in Garmsar plain. Data of groundwater level, climatic parameters of the study area, as well as 16 teleconnection indices from 1993 to 2016 were used for this study. Gamma test was used to analyze inputs sensitivity and so determine the optimal combination of inputs. Modeling was performed with multiple regression as well as multilayer perceptron artificial neural network (MLP) with two learning algorithms of Levenberg-Marquardt and Bayesian.Sensitivity analysis of model inputs with gamma test showed that among the climate parameters of the region, maximum temperature of Firoozkooh station and also teleconnection indices of SOI, EA, NP and WP had the most influence among the selected inputs. The results of the modeling using the most effective inputs showed that the best model is the neural network method with Bayesian learning algorithm, that in the model testing stage in Sardareh well, the MSE and the R2 were 0.36 and 0.93 respectively. In well 26, these values were 0.038 and 0.85, respectively. Also, rsults indicated that the use of teleconnections indices to predict groundwater level fluctuations in Sardareh well and in well 26 reduced the error rate by 5.6% and by 24% respectively.

Monthly water balance models (rainfall-runoff models on a monthly basis) are major tools in long-term planning of water resources. The basic structure of these models includes continuity equations for soil moisture storage, subsurface flow and groundwater. Due to the complexity of the formation process and the different sources of flow, Rainfall-runoff models have different structures and need to be improved, simplified and revised according to the studied catchment conditions. If there is a karst origin in the study area, because of its importance in providing drinking water, it can not be simply ignored in the modeling. In this study, the structure of daily reservoir Saturation Area Model (SAM) is modified to improve the prediction of base-flow and monthly runoff in Kazeroon and Barm plain karst basins. The results of the modified model (SAM-KARST( and original model (SAM) have been compared and then the performance of the proposed model has been evaluated. The obtained results showed a relative improvement in the performance parameters of SAM-KARST in comparison to SAM for the study basins.By considering the conceptual reservoir for karst origin in the model, the contribution of base flow obviously increased, which indicate the important role of karst origin in supplying base flow.

Drought as a long-term water scarcity situation is a challenging issue in water resources management. This phenomenon is one of the less expensive and less known natural disasters. Until now, most drought studies have been either univariate or bivariate. In this study, trivariate of drought analysis in eastern Iran for 13 meteorological stations in the period 1971- 2017 were investigated. SPImod index was used to extract the intensity, duration and peak drought parameters. In this regard, the ability of twelve copula functions of Clayton, Frank, Galambos, Platelet, Gumble-Hoggard, Ali-Mikhail-Hagg, Farley-Gumble-Morgenstern, HRT, Filip-Gumble, Joey, Gumble-Barnett and Sarmonov to create a joint -distribution of trivariate were tested. For this purpose, the nested method was used to connect two-dimensional joint functions and create a three-dimensional joint distribution function. To determine the best copula function at each station, RMSE, NSE-NSE, and maximum likelihood (ML) statistics were used. The results showed that the HRT copula function has the best performance in generating bivariate and trivial distribution functions. The results also showed that the use of SPImod greatly eliminates the disadvantages of general SPI and takes into account seasonal variations in precipitation in the calculation of SPI. The results of SPImod indicated that the highest percentage of dry months were observed in the Sabzevar station with 52% and the lowest in Torbat- Heydariyeh station with 35%, which were identified as the areas have experienced the highest and lowest dry months, respectively.

For over half a century, Iran’s modes of development has been based on several five-year Development Plans. The water resources development plans have been the center or one of the main drivers of the development plans aiming to achieve the Iranian society at a higher level of welfare. Dams and irrigation and drainage networks are the legendary elements of the development plans, which are based on a way of thinking and approach to development that is being inspired by the idea of Hydraulic Mission. An ethos that believes every single drop of water flows to the sea is wasted. This paper elaborates on a comparative study of the historical trends of the water resources development. By using the comparative study, it is concluded that Iran's water resources development mode is unique, and basically is based on the Hydraulic Mission. Irrigation networks are considered as the case study of the water resources development mode.

The appearance of climate change and its effect on different parts of water cycle make it essential to be aware of the status of water resources to correctly manage water resources. In this study, at first, the WetSpa model was implemented and calibrated for the basin, and then the output of the CanESM model was entered in to the downscaling model of SDSM under three scenarios and the meteorological data of coming years was received and finally the change of the runoff of the studied basin was determined by the use of hydrologic model for the coming years. The results of CanESM2 confirmed that at the most stations the temperature values would increase and the amount of precipitation would decrease, RCP 8.5 scenario shows more changes. The results of runoff simulation under climate change scenarios indicate a decrease in runoff amount and this amount was 5.53%, 13.89% and 25.1% for RCP 2.6, RCP 4.5 and RCP 8.5 scenarios. The high compatibility of the computational and the observational hydrographs, especially for the high inflows which were 92% and 86% for calibration and validation period based on the Nash-Sutcliffe index, emphasizes the efficiency of WetSpa model in the simulation of Shazand catchment.

In urban development projects, it is important the interaction of groundwater-flow and subsurface-structures, including cutoff-walls. Using a modeling approach to investigate these interactions can be helpful in planning to implement and strategies to reduce the adverse-effects. In this study, the numerical-code MODFLOW has been used with HFB package to simulate the three-dimensional groundwater-system of an urban area in Iraq, taking into account the geological layering and heterogeneity and the constructed cutoff-walls. These 40-meter-deep concrete cutoff-walls have been constructed with the aim of locally groundwater-level reduction to provide an ability to build the designed constructions under ground-level. For calibration and validation of model, the measured data of groundwater-level in 28 observation wells from February 2016 to September 2018 have been used. The aim is to investigate the interaction between the construction of subsurface concrete cutoff-walls and groundwater-system based on development plans. The results show that in the development of considered phases, an increase or decrease in groundwater-level can occur up to more than one-meter compared to pre-development conditions next to cutoff-walls. For example, under the constructed phase condition, the groundwater level changes are between -0.55 (maximum drop) to 0.44 meters (maximum increase) while with the completion of all phases, these changes are between -0.06 (maximum drop) to 0.14 meters (maximum increase), respectively. Preventing the water entering to the lower parts of constructions and maintaining the stability of adjacent structures are some of the issues, which should be observed considering the technical and managerial solutions suggested in this study.

Wetlands are valuable ecosystems that provide services to support the life of stakeholders. These ecosystems should be protected against the widespread degradation because of human and climate change. Monitoring and restoration of wetlands need information from all ecological parameters. But providing these information is complicated because of the vast area and complexity of land cover in wetlands. In this paper the Synthetic aperture radar (SAR) data were applied to map the land cover of Hamoun-e-Hirmand in 4 dates include 3 images in flooded period and 1image in dry condition. The radar backscatter of land-cover classes was investigated. Then the Support vector machine classification method was applied to classify the images. The results of this paper show the ability of radar date to map the flooded vegetation classes. Also, it shows the ability of these images to study the dry plants when the water resource dries out. The results of this paper are applicable in monitoring of wetlands and providing the data for ecosystem management and conservation.

Groundwater is the most vital source of water supply in Iran, and its sustainable use is an unavoidable necessity. Unfortunately, in the last few decades, the country's water resources have been in crisis in terms of quantity and quality, and the decline in groundwater aquifer levels has led to serious restrictions in more than 404 of 609 study areas, and a cumulative storage deficit of around 135 billion cubic meters in groundwater resources. In 2014, the implementation of the Groundwater Resources Sustainability Management Plan was approved by the Ministry of Energy to reduce groundwater abstraction. Despite the efforts of the Ministry of Energy over the past five years, the groundwater level is still declining. The use of global models in sustainability management projects can be a great help to better productivity of this project and change the approach of extracting groundwater resources in the country. Therefore, in this article, the leading countries in the field of sustainable water resources management programs have been identified and water resources sustainability laws have been extracted in these countries for implementation in Iran, to improve the rehabilitation and balancing plan in the next phases. Based on the experience of other countries, to increase the effectiveness of the sustainability plan, the most effective factor is the need to reform the structure of water governance and participation of local communities and without public participation, no tangible results can be achieved. It is also necessary to apply integrated and adaptive management of water resources.

Social and economic changes can multiplicate and rise water demands. As witnessed in many cases around the globe, limited renewable water resources have not effectively played a confining role for the developments, and with the rising demands, subtle transfer of rights or reallocations have taken place. Reallocation can be considered as a strategy to curb the issues of water scarcity and to exercise water demand management, in very different ways. Governance and water rights are determinative factors for the quality of reallocation with regard to the issues of equity and sustainability. By conducting a qualitative research through interviews, observations and document analysis, in this paper we have investigated the process of reallocation in Zayandehrud basin, Iran. The research revealed three mechanisms of reallocation: from previous right-holders to the government-defined purposes; from downstream to upstream; and from previous groundwater right-holders to new users. Lack of transparency and stakeholder participation in the reallocations without taking compensative measures is why here we have coined this experience a “silent reallocation”. As with the growing effects of silent reallocations, Zayanderud basin has witnessed contentious interactions among right-holders and the government. Reactions and decisions by the government reveal confusion and inability to deal with the complicated circumstances of the reallocations occurred. Meanwhile, though the reactions by the right-holder groups of farmers imply for raised local awareness and tremendous improvements in their social capacity to organize their power and influence, the sole request for furthering their access to water has complicated the controversies without distinguishable outcomes.

Increasing scarcity of water resources and its influence on quality and quantity of crop yield motivates farmers to apply deficit irrigation as an approach to overcome the lack of water. On the other hand, the importance of water as an intermediate good in agriculture has increased competition to access water as an economic good. Consequently, determining the irrigation water price under deficit irrigation is necessary to improve water productivity. In order to assess the impact of water price on water productivity, in this study green pepper was cultivated under four different water levels including 50, 70, 100 and 120% of crop water requirement. The crop was cultivated in the writers’ personal greenhouse under controlled and isolated environmental circumstances in Tehran. The crop yield was then harvested and its dry matter measured at the end of growth period. The results showed that after applying deficit irrigation and optimizing irrigation water depth, water price was reached to the maximum which was 183.44×〖10〗^3 Rials per cubic Meter. In addition, under deficit irrigation, water use efficiency was 5.67(kg/m³), physical productivity was 5.1(kg/m³), physical-economical productivity was 191.42×〖10〗^3 (Rls/m³/ha) and economical productivity was 1.04. Furthermore, the deficit irrigation before water depth optimization did not considerably affect irrigation efficiency, while after water depth optimization, deficit irrigation resulted better irrigation efficiency than full irrigation scheme.

Improving the efficiency of water use in the presence of a water market is an issue that, under the current constraints of water resources in the country, can guide the water management sector. This paper deals with the economic impacts of water market development. For this purpose, the effects of water market development by applying different pricing scenarios were investigated using a mathematical model (PMP). First, the economic value of different agricultural crops in the study area was estimated, then considering the average water tariff in agricultural lands and the economic value of water, by adopting different prices (water tariff, final cost and economic value), probable cropping pattern changes were calculated at Sabalan irrigation network. The results showed that there is a significant difference between the economic value of water and its tariff. As water prices rise, crop cultivated areas, yields and net gross profit decline. Alfalfa with the 58% decrease in cultivation area, had the highest decrease among agricultural crops, and showing that in different price scenarios, the pattern of crops is chosen by the farmers that more benefits per unit of water consumed.

Unlike the role and long history of the market mechanism in allocating resources and commodities but the role of market mechanism has been less considered by policymakers and planners in the allocation of water resources. But, in the current situation, with the increasing scarcity of water in most parts of the world, the use of this policy has been increasingly taken into consideration. In this regard, this study investigates the current status of water exchange on the downstream of Shirvan Barzoo dam in North Khorasan province. The results of this study show that in the current situation there are unofficial and dispersed water exchanges among the farmers, and more than 45% of the interviewees exchanged water that about 70% of them as buyers and 38% as seller have contributed. The cost of used water from the dam across different areas is also equivalent to 472 Rials per cubic meter. On average, 56% of the farmers tend to sell water at an average price of 3560 Rials and 48% of the farmers tend to buy water at an average price of 3328 Rials per cubic meter. In total, more than 91 percent of the farmers tend to create a local water market. Accordingly, it is recommended that local water markets, similar to its successful example in Mojahedin Shahroud, be established and strengthened to optimally use water resources and prevent the severity of the water crisis in the region.

The aim of this paper is to provide an application of Water Accounting Plus (WA+) Framework in the Tashk-Bakhtegan basin based on modification of the Soil Water Assessment Tool (SWAT) model. In this study, it has been provided an analysis of basin conditions in three time periods based on Water Accounting Plus (WA+). The analysis of the results indicates that the Tashk-Bakhtegan basin is a closed basin. In this basin, due to climate change, the manageable water resources have been remarkably declined and unfortunately, not only water managed consumption in the basin (Supplementary Evapotranspiration) have not been reduced but also it has been considerably increased (53%). This has led to a decrease in outflows as the water right supplier of the lake. Moreover, the results indicate an increase in groundwater resources deficiencies and their unsustainable exploitation. Increasing transpiration of plants in agricultural land is another factor influencing the current situation of the Tashk-Bakhtegan basin, due to the expansion of the land area and the increase of high water consuming plants as well as significant contribution of the soil evaporation of the total nonbeneficial consumption of the basin. At the other hand, a significant amount of agriculture water withdrawal is returned to the water basin cycle which emphasizes on “depletion “to “withdrawal” planning.