River basin organizations (RBOs) are organizational bodies that set the ground for the Integrated Water Resources Management approach in the scale of a basin. The forms and missions of such organizations are different in different river basins and their performances are affected by different factors. The first and only experience in Iran regarding the establishment of an RBO is the Zayandehrud River Basin Council which was established in 2013. The Council then transformed to the Zayendehrud Restoration Working Group in 2019. This study aimed at assessing the performance of the Zayandehrud Council in the six years of its existence using a performance assessment framework developed in the study. The data needed were gathered through documents, questionnaires, field investigations and interviews. The performance of the Council was assessed in three dimensions of “efficiency”, “effectiveness”, and “learning”. In terms of efficiency, the results showed that the Council suffered from lack of professional human capacity and has not been successful in implementing the river basin management. Collaborative participation was missing in the Council. Furthermore, sectorial thinking and mistrust dominated. There were also lack of binding and accountability mechanisms in the Council and in the associated organizations responsible to implement its approvals. According to the effectiveness dimension, the Council decisions were not affected by the basin hydrological conditions, rather they were mostly influenced by the expected available water to adjust water allocations. The Council was also unsuccessful in resolving social challenges and sometimes even reaching decisions in the Council’s meetings was hindered by such challenges. According to the learning dimension, the Council was not authorized to check the persisting rules, neither was it allowed to modify the overarching taken decisions and policies. Thus, the learning process has ended to destructive results.

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, Zayandehrud 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.

Zayandehrud is located in central of Iran. It is important habitats for living organisms and has a main role in diversity of flora and fauna too. Eight stations from Zayandehrud bridge up to Khajoh bridge were selected to determine Mulloscian assemblage. Malcological studies led to identification of I pelecypoda species (Corbicula fluminalis) and 4 Gastropoda species (Lymnae gaderosina, V. valvata piscnalis, Physa acuta and Physa sp.). All of Gasteropoda species belong to Hycanian province and only Pelecypoda belongs to North Africa and Western Asia fauna.

Multiplicative seasonal autoregressive integrated moving average models are appropriate for the monthly stream flow of the Zayandehrud River in western Isfahan province, Iran, through the Box and Jenkins time series modeling approach. Among the selected models interpreted from ACF and PACF, seasonal multiplicative ARIMA (1,1,0) × (0,1,1) satisfied all tests and showed the best performance. Seasonal moving average parameter in the model indicates periodicity, and long memory in the streamflow, while a nonseasonal autoregressive parameter indicates the linearity of the monthly streamflow. The model forecasted streamflow for 24 leading months showed the ability of the model to predict and forecast statistical properties of the streamflow.

So far, many researches have been conducted in various fields of the water shortage crisis, mostly in environmental and economic fields, and in a few of them, attention has been paid to the influence of cultural elements as a moderating factor of the effects of this crisis. The present research has been formed to provide a paradigmatic pattern of cultural resilience in the water shortage crisis of Zayandehrud, which was carried out using a qualitative method and grounded theory approach. Using theoretical sampling and the snowball method, the number of 24 people who were interested and concerned in the field of water shortage issues and had sufficient information, experience, or knowledge in this field were selected and during the in-depth interview Semi-structured, they expressed their answers. Data analysis was done with the Colaizzi method in the framework of grounded theory. The Lincoln and Goba evaluation method was used to validate the research, and the validity of the data was confirmed by going back to the interviewees and two coders. The findings were 22 categories, "accepting the phenomenon of water shortage as a reality" as the pivotal phenomenon, 3 categories of causal condition (sufficient information, water literacy, communication) 4 categories of contextual condition (hope, religious beliefs, attachment to the residence, economic dependence) 5 categories of intervening condition (trust, pragmatism, attitude, social responsibility, collective cooperation) 5 interaction strategy (change in habits of oneself and others, participation, prevention, saving) and 4 categories of consequences (productivity, entrepreneurship, creativity and awareness) were categorized.

Knowledge of the spatiotemporal variations of river contamination from surface water enhances management decisions. This study assessed water quality parameters from 2000 to 2020 in four seasons in the Zayandehrud River of Iran. Principal Component Analysis (PCA) was utilized to decrease the dimensionality of water surface pollutants. Then, general linear models (GLMs) were applied to determine the impact of sampling stations along the river, season, year, and different land uses (agriculture, pasture, urban, and water) on the selected water quality parameters. The best model was selected using the Akaike information criterion (AIC) method, and the Wald test results indicated that the station factor significantly influences PC1 and PC2. The most positive effect was noticed in areas between urban (1000-meter buffer) and PC1, agriculture land use (10000-meter buffer) and PC2. In addition, the most significant damaging consequence was detected between agriculture (100-meter buffer) and PC1, pasture (1000-meter buffer) and PC2. This paper revealed that a combination of statistical techniques for evaluating spatiotemporal variation in water resources could benefit integrated environmental management.

In this study, chemical quality of Zayandehrud river between Zayandehrud Regulating Dam and Nekouabad Diversion Dam, three discharging drains and one Fehlman well were measured using HPLC with determine the pollution concentration of diazinon insecticide from July 2006 to March 2007. Also, Zayandehrud’s assimilative capacity was determined. The results showed that river water and drains were not polluted to diazinon. Physical, chemical and biological factors effective in the diazinon detection were assessed. Diazinon was detected in the groundwater sample in October with concentration of 32.1 ng/L. This level was lower than the maximum permissible level for drinking water. Also, the NO-3 concentration in this month was 24 mg/L that is 2.4 times the standard level (10 mg/L). Due to the increased discharge of different wastewaters to Zayandehrud, its assimilative capacity decreased from upstream to downstream. So, prevention of use of pesticides and pre-treatment of wastewaters that are discharged to this river need more attention.

The purpose of this study is using game theory to evaluate the relationship between the five residential, agriculture, industry and mining, recreation and environment water demands in the Zayandehrud basin. In order to estimate the demand and supply functions, this study used system of simultaneous equations in the period 2001-2012. So the industry and mining and agricultural demand estimate with using a translog production function, the cost associated with it and using the second Taylor series expansion and the water cost share equation extracted in derivative with respect to the price of water and Shepard's lemma. The industry and mining demand Marginal price was estimated 12072.2 and 1698.442 Rials. Municipal water demand estimate as a nonlinear function by maximizing the Stone - Geary (Klean- Rubin) utility function restricted to family budget and the taking into account the minimum water requirement as a function of water temperature and population. The daily per capita minimum water requirement was estimated 101.91 Lit. The results of the above estimates under the two-play man and man (HH) and the game man and nature (HN) was evaluated in three states. The equilibrium estimate under the (HH) game, regardless of the demand for recreation and the environmental is for quantity 2696.74 mm3 and price 1932.37. In a wider game, by taking WTP of water and consumption requirement in recreation and the environmental sector in horizontal plural form the water market equilibrium between man and nature play is 2743.58 for quantity and 1973.64 for price. Finally, in the third case in the water market, by taking WTP of water and nonuse water in recreation sector in horizontal plural form and WTP of water and consumption requirement in the environmental sector in horizontal plural form the water market equilibrium between man and nature play is 2777.83 for quantity and 20004.715 for price.

The Zayandehrud river total flow is composed of two main components, i.e. total base flow and direct runoff. The former component includes secondary components resulted from groundwater discharge, overland flow produced by slow melting of snow and delayed interflow. The later component (the direct runoff), consists of secondary components of surface runoff from precipitation, overland flow produced by prompt snow melting and rapid interflow. The separation of main components of total stream flow has been performed by "HYSEP" model on the basis of daily stream flow data. This software employs three methods (fixed interval, sliding interval and local minimum) to compute values of above-mentioned main components. Since the flood intensity related to maximum value of direct runoff and drought intensity related to minimum value of total base flow, both can be analyzed for different return period using Zayandehrud stream flow long term data. On the basis of obtained results, a flood with total stream flow equal or exceed to 161.05 cms and direct runoff equal or exceed to 96.28 cms arise every 196 years. On the other hand, a drought with total stream flow less than or equal to 16.09 cms and total base flow less than or equal to 13.83 cms occur every 16 years.

Application of drought early warning system is an important strategy for drought management. It is more pronounced in the arid regions where dams have vital role to overcome water shortages. This papers aims to develop and apply such a system that includes three main components, which are 1) drought monitoring, 2) forecasting inflows and water demands and 3) calculation of a warning index for decision about drought management. The system is presented for the Zayanderud Dam. For this, the future six months river inflows and demands are forecasted at different probabilistic levels using the artificial neural networks and considering respected uncertainties. Also, five drought levels are indicated based on the historical records of dam’s storage and the self-organizing feature map technique. Furthermore, a drought alert index (DAI) is defined using current storage of dam and the forecasted flows and demands. Finally, the different alert levels are estimated, which vary from normal to sever water scarcity. The results showed that application of the designed warning system can have effective role in the dam’s operation, rationing policy and reducing drought losses.