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.

With all the importance of water in the economy Iran is, every year floods volumes high of waters and Prolific soils of the country and access out to the desert, lakes and seas delivers. Kashkan River Basin of sub basins important is basin Karkheh. This study examines the changes in annual rainfall, trend the Runoff, rainfall- runoff, frequensity rainfall 24 hours and intensity in the catchment bastion of rainfall in basin Level is very different. And according to Local water conditions and topographical features of the high zagros mountains- rainfall received in the basin every different despite the stability of average annual rainfall, annual runoff coefficient of the additive is steep and significant. Comparison average first decade and second decade period 29 years showed the annual runoff coefficient in the second decade of the first decade has increased 84 percent. Increased runoff and flood in recent years, only to cause precipitation of quantitative terms, no matter what, but is seems that other factors such as land use changes, deforestation, degradation of Grassland into Agricultural land, urban development, rural housing development and the impact of flooding has increased dramatically in rural areas. It is expected that more severe floods occurrence. The monthly distribution of rainfall in the basin suggest that the rainfall on the basin at the end the year is cold. Instead of the heat loss due to weather condititions generally are extremely liquid and became a flood.

Many river basins that supported hydraulic civilizations for thousands of years are being converted into a very unsustainable and fragile ecosystems. This process threatens the basis of sustainable development of communities settled in these river environments. The major questions of this paper are as follows: 1-How have the basins been changed into unsustainable environments? 2-What are the guidelines to direct river basin development and management towards sustainability? 3-What would be a study model for planning sustainable river basin development and management ?

In recent years, in order to revive the Urmia lake and preventing the negative environmental impacts, the water transfer project from Zab River to Urmia Lake has being studied and implemented. In this paper, it is tried to assess the possibility of morphological changes of Zab River due to implement of project at the downstream of Kanisev dam. The research method is mainly analytical method.The data of this study include Geological map of 1/100000 scale, areal photographs, LANDSAT 8 (ETM sensor) satellite imagery, GDEM images of ASTER with resolution of 15 meter, meteorological data and hydrological surface water of the under study area.The data were collected using libraries and referred to agencies and organizations, web sites and field surveys. Results showed that after water impoundment of Kanisev dam and transferring water to Urmia Lake, the average of the Zab River discharge in the hydrometric station of Grzhal will decrease from 1464.72 to 653.42 million cubic meters per year and the bed river at downstream will decrease drastically. So that in September and October. Zab bed river from dam wall to the Abkhorah tributary will be dried approximately. The decline of flow will cause changes of the morphological indexes such as cross-section and longitudinal-section and hydrological features similar to depth and velocity of flow. With reduction of discharge at the downstream of Kanisev dam, at A section, the flow of river will pass of the deepest bed river in which new terraces, narrowing cross-section, remove the side vegetation or retreat to far from will occur. At B section, the power of flow will focus toward the side of the river and also cut-off them, finally lead to fill the pothole using deposition. At the last section, C, with increasing distance from Kanisev dam and enhance sediment load rather than transport capacity, both depth and width of the bed river due to creation the point bars along flow and sedimentation at the sides will decrease.

Geomorphic indices of active tectonics are useful tools to analyze the influence of active tectonics in an area. These indices have the advantage of being calculated using ArcGIS and RS (Remote Sensing) packages over large areas as a reconnaissance tool to identify geomorphic anomalies possibly related to active tectonics. This is particularly valuable in Great Karoun River Basin of Zagros, where relatively little work on active tectonics based on this method was done. The study area in central Zagros fold- thrust-belt of the southwestern Iran is an area with NW–SE oriented structures provides an ideal location for testing the concept of an index to predict relative tectonic activity on a basis of river system or mountain front. Based upon values of the stream length-gradient index (SL), drainage basin asymmetry (Af), hypsometric integral (Hi), ratio of valley-floor width to valley height (Vf), index of drainage basin shape (Bs), and index of mountain front sinuosity (Smf), overall index as index of relative active tectonic (Iat) was resulted that is a combination of the other indices. This indices are used to divide the landscape into four classes of relative tectonic activity. After measuring indices it is concluded that this part of the Zagros zone has variable rates of active tectonics. Based on corrected Iat values, the study area was divided into three parts: class 1 (very high relative tectonic activity, %24 in area; such as some parts of the east and central zone where Main Zagros Reverse Fault and Dezful embayment fault have the most influence); class 2 (high relative tectonic activity, 63% in area; such as most parts of the area in east, west, north and center where action of faults are lower than the previous class); class 3(moderate, 10% in area; such as most parts of the area in north and south where action of faults are the lowest). Therefore, we don’t have class 4 in this area, and 1% of basin is not measured for the indices because it is located in coastal plain of Khuzestan.

Flood is natural phenomena. That human social accept it, is inevitable. But the reason of occurrence, size, and repetition is multifactor that change condition region of climatology, natural and geographical. Obviously the reason of flood is precipitation. But studies show there is not liner relation with this factor. As such disruptive this relation in additional to geographical condition has physical properties of basin and is properties of hydrologic. The case study of this research is located northeast of Tehran. It located in the east longitude from 51o 22’ to 51o 52’ and north latitude from 35o 45to36, 50. In this research for modeling of flood flow of Jajrod river basin first effective indexes in flooding with use of experience past study and special traits of basin recognized that superlative indicator effective in flooding region has been characterized and proportion of each sub basin was characterized. Ultimately, with the use of multiple regression method (enter method) the flooding model of basin was produced. Required layer for evolution with use of GIS software was produced. Conclusion of research shows in physiographic properties of studied, invoices of ratio of figure, ratio of density, time concentration, basin surrounding, sum of length of river, length of first class River modeling of flooding has maximum importance.

Lag time is a parameter that appears often in theoretical and conceptual models associated with river basin. The river basin lag time is an important factor in linear modeling of river basin response. Generally, all hydrologic analyses require at least one of the time parameters of river basin and, in the majority of cases, time of concentration or lag time are used. In this research, storm data from 6 stations in the North Karoon river basin (in Iran) were analyzed. From this analysis, 23 events were selected. Then, in one experimental sub-basin located in this river basin, the lag time was calculated using field method. In this method, performed in the Darehbeed - Samsami study area, lag time was computed from a hydrograph generated by discharge measurement of a triangular scaled spillway. After that, 23 events were divided into two groups, including, one for a newly developed empirical model (70 percent) and another for validation of this model (30 percent). The results obtained from this research based on coefficient of determination (R2), root mean square error (RMSE) and relative error (%RE) statistical measures showed that the agreement between the computed (from new empirical model) and measured data is good.

Background and Objectives: The occurrence of climate change and its impact on surface water and groundwater resources, along with inappropriate management of water resources have led to an increase in the social and environmental vulnerability of river systems. Assessing the vulnerability of river basins, especially in developing countries such as Iran is essential and is considered as one of the main priorities of the water resources planners for the sustainable management of these resources and for the formulating of policies consistent with the regional conditions. In this line, this paper focuses on the assessment of the vulnerability of the Jarahi River Basin. Materials and Methods: The study area of this research, the Jarahi River Basin, is located in southwest of Iran with an area of about 24000 square kilometers and a population of about 870000 people. In this research, the River Basin Vulnerability (RBV) method was used to assess the vulnerability of the Jarahi River Basin. This method examines the vulnerability of ecosystem and human simultaneously and consists of a total of six main indicators including ‘ governance’ , ‘ economic status’ , ‘ social condition’ , ‘ environment’ , ‘ water stress’ and ‘ natural hazards’ indicators. In this method, data are evaluated quantitatively. The combination of these indicators is based on a raster summation algorithm which can be carried out in the ArcGIS platform. Results: The anlysis shows that the vulnerability of the Jarahi River Basin corresponding to each of the indicators of governance, enconomic status, social condition, environment, water stress and natural hazards are 0. 76, 0. 41, 0. 061, 0. 43, 0. 44 and 0. 84, respectively. The results exhibit that the Jarahi River Basin is severely threatened by natural hazards and in particular, the flood hazard threatens all parts of the river basin. It is also exposed to high water stress. The highest water stress (0. 76) associated with the Shadegan sub-basin that is located in the southern part of the basin. In addition, the Saiddon sub basin has the lowest literacy rate among the sub basin of the Jarahi River Basin with the rate of 79%. A significant part of the Shadeghan sub-basin exhibits considerable environmental impacts, interpreted as a discernible sign of human footprints in the area. Conclusion: Generally, in the Jarahi River Basin, the vulnerability of three indicators, namely governance, water stress and natural hazards are quite significant. In particular, flood assessment analysis shows that almost all the river basin is highly susceptible to flood hazard. Also, seismic hazard threatens a considerable portion of the Behbahan and Takht-E Deraz sub-basins. Moreover, regarding the natural hazards, given the high potential of drought, flood and earthquake occurrences in the research area, it is possible to somewhat reduce the incurred damages caused by these phenomena in the river basin by means of paying due attention to knowledge, awareness, planning and efficient management. The results regarding the water stress show that almost half of the basin (mostly the Shadegan sub-basin) suffers from high water stress. Concerning the water stress indicator, given that the excessive use of water in the agriculture sector is mostly responsible for the high vulnerability state, changing the current land-use and accordingly the cropping pattern in the Jarahi River Basin will potentially have a positive impact on water stress indicator. Through controlling corruption, improving Iran’ s political stability status and reducing the government fragility index, an improvement in the governence indicator can be achieved.

The present study reports range extension of Moenkhausia oligolepis to the Pindare riverdrainage, of the Mearim river basin, and Itapecuru river basin, Maranhao state, northeastern Brazil. This species was previously known only from Venezuela, Guianas, and the Amazon River basins. In addition, we present some meristic and morphometric data of the specimens herein examinedand discuss on its diagnostic characters.

Since the selected habitat indexes provide a description of the habitat characteristics of a species, this study was conducted to investigate the habitat preference of Garra rufa in Dinorab River (Kermanshah Province), a tributary of the Karkheh River basin. For this purpose, the habitat characteristics, including water depth, water velocity, river width, potamal area width, predominant type of bedrock cover, pH, temperature, electrical conductivity (EC), total dissolved solids (TDS) were measured and recorded in 18 sub-stations belonging to six main stations from downstream to upstream. The used and selected habitat ranges were obtained according to the availability of each habitat unit for each variable. The results showed that the most preferred water depth is 26-30 m with a suitability index (SI) of 0. 779, river width of 6-7. 2 m with SI of 0. 7, the water velocity 0. 24-0. 31 m/s with SI of 0. 38, bed structure with medium diameter of 5-5. 5 cm with SI of 1, water temperature 18-19 °, C with SI of 0. 618, pH 7. 32-7. 44 with SI of 0. 545, EC 290-310 with SI of 0. 767, TDS in the range of 580-610 ppm with SI of 0. 712 and potamal width 4. 8-6 with SI of 0. 634. The results showed that the Dinorab River is a moderately suitable habitat for Garra rufa.