محمدرضا غریب رضا

The awareness of floods and estimating the debris flow is a fundamental step for assessing risk and planning in the watershed. The village of Sijan, located in the Southern Alborz, is one of the areas threatened by debris flows. The research aimed to estimate the volume of debris flows along 700 m of a stream of Sijan Village time range from 2018 to 2021. The study method included surveying the stream in two-time intervals, which involved one concrete and four gabion checkdams, and calculation of erosion and sedimentation happened via debris flow using the Civil-3D software. Results showed that five check dams had 823 m2 and 750 m3 area and volume, respectively. Debris flows covered 25500 m2 after the flood in 2019, in which the estimated erosion and deposition volumes were 7250 m3 and 10100 m3 according to the elevation difference technique. The Sijan stream channel experienced sedimentation and erosion along the northern and southern banks. Implemented watershed management measures have played a vital role in mitigating the risk of debris flows, especially at the concrete check dam.

Rivers are highly variable systems and one of the most important water ecosystems that play an important role in the life of humans and other living beings and are easily affected by pollution. (Maanan et al., 2015). The concentration of heavy metals in sediments is generally several times that of water bodies, and heavy metals are not destroyed and decomposed during natural processes, therefore, heavy metals can be stored in sediments and remain there for a long time. For this reason, surface sediments are one of the main reservoirs of heavy metals and other pollutants (Islam et al., 2016). The Karoun River is not immune from these pollutions and many wastes from metal, petrochemical and oil, cellulose and food industries, domestic and hospital sewage and agriculture are discharged into this water environment. On the other hand, this river supplies water for these industries and is a source of drinking water for cities such as Ahvaz, Khorramshahr and Abadan. The fishes of this great river are one of the main sources of nutrition for the people of the region, as a result of the presence of pollutants, especially potentially fertilizing elements in Karoun, it can cause pollution of sediment, water and food and affect the life cycle of this great river. damage (Rastmanesh et al. 2015). Considering the quantitative extent and diversity of human activities in the Khuzestan plain and the entry of all kinds of effluents and sewage into the Karoun River, investigating the pollution, pollutants and risk levels is an inevitable necessity. Therefore, this research aims to determine the level of enrichment of elements, to determine the ecological risk and dangerousness of pollution in comparison with the quality standards of sediments in the Karoun river in the Weis basin to the beginning of Ahvaz city using geochemical data and statistical analysis. It was done by XLSTAT2018 software. 

In order to evaluate the pollution of the sediments of the Karoun River bed, 22 samples were taken with a boat from a depth of 0-10 cm and based on common methods in sedimentary geology Tucker (1988) and Arzani (1997) of sediments was harvested. Then, the samples were prepared in the water and soil laboratory of the Soil Conservation and Watershed Research Institute for the granulation test and determination of the concentration of toxic metal elements. In order to investigate the state of sediment pollution, the obtained concentrations have been compared with the standard values of ISQGs, severe effect level (SEL), probable effect level (PEL) and global base values. 

According to the results obtained from the grading, the sediments of the river bed in most of the stations have a granular texture and are of the type of mud, silty sand and sandy mud. These sediments have an average of 0.62% organic matter in terms of organic matter. The results of the pollution level also showed that the concentration of toxic elements As, Cr and Ni have values beyond the standard values of ISQGs and PEL. Based on the comparison between sediment quality criteria and standards, Karun River in the studied area has clean sediments from the point of view of Cd and Pb elements. The results of calculation of enrichment factor showed that Zn element has moderate to significant enrichment. The enrichment of Cu, Ni and Cr was in the range of moderate pollution. The semi-metal As is in the range of low to medium enrichment and the two elements Cd and Pb have low enrichment. The average enrichment of elements is Zn>Ni>Cu>Cr>As>Pb>Cd. Finally, the results obtained from the risk index showed that the values of the risk index for all samples are in the low risk range (RI<150). The statistical analysis of the samples showed that there is a significant positive relationship between Cr, Ni, Cu and AS with clay. So clay particles are the main carriers of Cr, Ni, Cu and AS elements. A high correlation coefficient between elements indicates a common source, mutual dependence, and the same behavior during transportation. 

The current research leads to sufficient understanding of the geochemical situation and any change from natural conditions and revealing the local and thematic enrichment of pollution levels for aquatic animals and users, especially in the field of agriculture and food cycle in the Karun River in the Vays basin to the city of Ahvaz. has been The results of the enrichment factor showed low to high pollution for selected elements. The potential ecological risk values of all selected elements except As in sample 21 are in the low risk range, and AS in sample number 21  is in the medium risk range . The risk index values for all samples are in the low risk range . Based on the comparison of sediment quality criteria with the standards, Karoun River has clean sediments from the point of view of Cd and Pb elements in the studied period. So that 100 percent of the samples have a concentration lower than ISQG. Cr with 27% and Ni with 100% has a concentration beyond the PEL pollution level and all the values obtained for Cr and Ni elements have a concentration beyond the minimum concentration of the ISQG pollution level. In this way, there is a possibility of poisoning for aquatic animals and water exploitation by the toxic elements Ni and Cr. Comparing the concentration of elements with the standards showed that in stations number seven (subordinate to Mahi Shiban), 21 (east coast of KianPars) and 10 (Kouresh sewage), Cr and Ni elements have concentrations beyond the PEL pollution level and more As. It is from the minimum level of ISQG and the most polluted stations are in the study period. So, the maximum enrichment of Cr and As has also happened in station number seven. Element clustering analysis showed that organic materials are the main carriers of Cu and Zn elements and clay particles are the main carriers of Ni and Cr elements. Also, in the case of Cu and As elements, clay particles play the main role. But the toxic metal Pb has not shown any significant relationship with other elements as well as organic materials and clay particles. So Pb element has a different origin than Cu, Zn, Cr, Ni and As elements. The results of principal component analysis, while confirming the correlation coefficient and cluster analysis, showed that Cu, Zn, Cr, Ni, and As are of anthropogenic origin, and Pb and Cd are of terrestrial origin. This study has an important contribution in determining the origin, pollution and ecological risk of potential fertilizing elements and can help in identifying pollutant sources and pollutant control.

Mechanical properties of most soils alter upon the increase of moisture and saturation. In some soils, certain phenomena appear due to increased moisture. Some of these phenomena lead to major damage in development projects. These soils are called Sensitive soils to water”. The most significant types of these soils are swelled soils, dispersive soils, and collapsible soils. Dispersive soils refer to clay soils that are easily washed up in waters with a low concentration of salt. Dispersion is a progressive phenomenon that starts from one point and is gradually extended. The start point of the dispersive phenomenon may refer to cracks resulting from shrinkage, soil deposition, or cracks made due to the roots of plants. This phenomenon is of great importance in such plans as soil dams and water supply channels where there is a water concentration inside the soil too. One of the essential reasons for soil erosion and sediment production in irrigation and drainage networks is the instability of canal soil, so it is necessary to use erosion control methods in parts of the canal route, especially at the intersection with other structures. To this end, the solution investigated and tested in this article is the use of biological mulches to reduce the erosion of the side slopes of earthen channels.

This research has been conducted on soil with a Loam sandy texture of irrigation and drainage channels network of the Arayez Plain of Khuzestan that lies on the west side of the Karkheh River. Using a simulated system, two-nozzle rainfall of the K18 feature was performed. To determine the effect of mulches on parameters of side wall erosive resistance of the soil structure, after the soil of the region passes through a sieve of 4.76 mm was put in the basin designed for 1 x 0.33 x 0.1 m for about 25 kg. After filtration, leveling, and pressing the soil to the edge of the Flume basin proportionate to the physical special weight of the soil, the stabilizing materials, and different bio mulches were sprayed in their different concentrations. Then, the basins inside the Flume with a side slope of 80% were put into a depth of 10 cm. In this research, with the objectives of determining the type and most appropriate level of biological mulches and their effect on the soil erosion resistance parameters of the lateral wall of the drainage channels of the Araiz plain of Khuzestan, the necessary experiments were conducted in the rain simulator laboratory of the Soil Conservation and Watershed Research Institute. So that using four types of water-based biological mulch, which were named with numbers 1 to 4 and at three levels of minimum (C1), medium (C2), and maximum (C3), experiments were conducted on the soil sample of the researched area. Each of the experimental treatments on a flume with a side slope of 1 to 1.25, similar to the side slope of canals in nature, was repeated and simulated three times in two rainfall intensities of 30 and 80 mm h-1. In each experiment, primary and secondary soil moisture, runoff volume, sediment weight, the intensity of water penetration in the treatments, and the shear strength of the treatments were measured. The experiments were conducted in a randomized complete block design in the form of split plots and the data were analyzed using SAS software and the averages were compared using the Student–Newman–Keuls (SNK) multi-domain test. Finally, by using mathematical models with optimization and minimization of sediment amounts and economic costs, the most suitable treatment for stabilizing the lateral walls of drains was determined. SPSS software was used for the statistical analysis of data and ANOVA and the Duncan test were used for the statistical comparison of data. Considering the tables obtained from data variance analysis and considering the statistic F and significance level, it can be said that all treatments are different in a significance level of 5% concerning the extent of sediment and there is a significant difference in the sediment amount.

The tests conducted on the soil of drainage channels of Arayez plain with a loamy – sand texture indicated that the presence of mulch coverage results in reduced sediment arising from rainfall in the manner that by the increase of density in any of the mulches, sedimentation reduces accordingly. The results obtained from the statistical analysis of this research confirmed that there is a significant difference in a level of 5% between sediment amounts of test control and mulch treatments for the sample of the soil under study. Therefore, bio mulches have an effective role in erosion control and the decrease of sediment from the walls of soil channels. The results indicated that only two types of biological mulches used in this study had a positive effect on shear resistance. General Linear Model (GLM) results showed that the interaction of two parameters of rainfall intensity with the type of treatment on shear strength is significant, so the interaction of rainfall intensity parameters with the level of materials used was not significant at the 5% level. In addition, the interaction of the type of treatment with the level of the materials used was also significant. According to the results of the analysis of variance in investigating the role of rainfall intensity on biological mulch treatments, it was found that rainfall intensity affected shear strength.

According to the above photos, all mulches compared to the control treatment have had a remarkable effect on the decrease of sediment. Moreover, it was found that the increase in the density of mulches used in all densities has had a remarkable effect on the decrease of outlet sediment. Furthermore, it was realized that the rainfall factor affects the increase of sediment. Thus, this effect in mulch 2 is the least effective in such a manner that upon increased rainfall in mulch 2m we see the minimum increase in the amount of sediment. The results after conducting system engineering and analyses related to the optimization of sediment amounts and economic costs indicated that mulch 2 at the C3 level has the best efficiency in increasing shear resistance. This conclusion could help the decision makers to allocate their soil conservation budget for the best performance activities.

The research objective was to identify and map the tidal zones that play a decisive role in integrated coastal zone management. Methodology designed based on the expert interpretation of the spatial boarders of the High Astronomical Tide (HAT), the spring and neap tides on the Sentinel-2A satellite images of 2018 with a spatial resolution of 10 meters to determine the risk of long-term flooding, supratidal and subtidal zones, respectively. In the coastal region of Bushehr province, an area of 81,000 hectares is subject to long-term flooding, 15,000 hectares are subject to monthly flooding, and 53.5 thousand hectares are subject to daily flooding. The results showed that up to 62% of the coasts of Bushehr province are tide-dominated coasts. Implementation of sustainable land use in the coastal region of Bushehr province is not possible without considering this risk. However, these lands are suitable for developing aquaculture, salinity, and mangrove forestry.

The present research aimed to protect the physical space and obtain the desired land-use planning through a shoreline management plan for the Bushehr city district. To achieve objectives, considering a sea-based approach, forty-seven environmental, infrastructural, and human characteristics have been involved along with the management units (Sedimentary cell, sub-cell, and shoreline-sector). Determining the appropriateness of the development of structures and infrastructures such as ports and mooring berths, infrastructure for coastal-maritime tourism, and coastal protection structures such as dykes and coastal walls in three proportions (suitable, relatively suitable, and unsuitable) along the nine shoreline sectors with attention to the environmental and passive defense considerations were the research outcomes. The present study concluded that the construction of the coastal structure along the Abbasak Bay and Piazy estuary is inappropriate. In contrast, the coastline of Bushehr Peninsula was recognized as suitable for the establishment of the tourism infrastructure and mooring structures, commercial and fishery ports, and coastal protection structures.

Integrated Coastal Zone Management (ICZM), as a regional management plan in Iran, is based on the conservation, development, and coordination-integration approaches. The conservation approach has focused on identifying and ranking the environmental issues, and presenting the action plan to conserve natural resources and overcome problems. One of the pre-requisites of this action plan is to investigate the environmental issues in the coastal-maritime area. Therefore, this study was carried out under the integrated management of the coastal zone of Bushehr Province aiming to determine the level of the importance of the environmental issues in the Asaluyeh coastal zone, and to present an action plan to protect ecosystems and overcoming of the problems. Accordingly, environmental issues were identified through reviewing the governmental documents and several valid references. A questionnaire was prepared based on the most important environmental issues and then filled by the elite community in Bushehr province, specifically Asaluyeh city, based on the Likert scale. The final step of the analysis was performed using the DPSIR framework. The Results showed that coastal-maritime environmental issues had the highest importance (8 - 11.75) consulting the elite persons in Asaluyeh city, which indicates the role of anthropogenic activities resulting in natural resources and ecosystems getting polluted. The high-ranked environmental issues are as the following: inappropriate landfilling and disposal of waste, improper disposal of wastewater, pollution of beaches with heavy metals, pollution of Asaluyeh estuary with urban-industrial wastewaters, reduction of aquatic reserves, population, and overloading of trashes on beaches. Consecutively, the air quality index driven by oil and gas industries was another important metric with a 7.2 importance level. The present research has presented an action plan consisting of 100 executive actions. Furthermore, the responsive stockholders and partners, as well as quantitative indexes for evaluation and monitoring actions through certain milestones up to the horizon of 2025 have been introduced. The measure to be implemented driving forces-based actions including preventive policies, reconsideration, and awareness of decision-makers; pressure-based actions focused on spatial land use planning and using natural resources; state-based actions including recovery, restoration, amendment, and empowerment of ecosystems, reconstructing the existing guidelines in addition to developing health and insurance for beneficiaries; and impact-based actions including spatial planning and beneficiaries’ failures, control and reduction strategies, as well as monitoring and assessments. All these measures were finally submitted to local and provincial decision-makers as a directive. It is also believed that the present research method could be inspired by other studies addressing the same aims in other coastal areas.

The Karun River provides an important sedimentary environment for the Great Karun Watershed, which receives large amounts of oil, industrial and municipal sewage, and agricultural wastes. The dominant physico-chemical conditions, which are controlled by water discharge rate and the river morphology, determine the conditions for the absorption of toxic metal and levels of pollution for aquatic creatures and utilizers; in other words, the food chain. Therefore, the study range limited the urban area of Ahvaz between the Fifth Bridge and the Sayyed Khalaf Alley.  The research objectives were to determine the concentration of seven toxic metals, namely: Cu, Cr, Cd, Zn, Pb, Ni, and As, and their consequences on the levels of pollution. A deterministic strategy of sampling was chosen based on the identified and surveyed contamination points. In total, twenty-one superficial sediments (0-10 cm) samples were collected using an undisturbed core sampler. The analytical procedure was carried out using the ICP-MS equipment following the Geological Survey procedures. The research method was designed to compare the concentration of toxic metals to their standard levels (ISQGs, PEL, SEL) of sediment quality guidelines of freshwater sediments to find out the level of pollution risk, and the high-risk ranges along the river reach. In addition, the enrichment factor was calculated to determine the rate at which the concentration of toxic metal bias from their background levels. The coefficient of variation of the predominant concentration of elements indicates the contribution of human pollutants in increasing their concentration in sediments and the order of enrichment of elements is Zn> Cu> Ni> As> Cr = Pb> Cd respectively in the surface sediments. The Karun River superficial sediments, especially from the Kianpars Bridge to the Fifth Bridge, were in a harmful condition for Cr, while the concentration was higher than the PEL level (90 mg kg -1). The study concluded that the Ni concentration of the sediments along the studied range was higher than the ISQG, PEL, and SEL (50 mg kg-1) standard level. Thus, aquatic bodies and the users of the Karun River water in such a range are exposed to severe poisoning due to nickel pollution. This situation has occurred while the drained sewage along the districts of the Kianpars Bridge to the Black Bridge and the Naderi Bridge to the Eighth Bridge has played a critical role in releasing pollutants. Thus, preventive measures to control pollutants from the source and methods of neutralizing and removing pollutants from the Karun River sediments are firmly recommended.

Rivers, as the living artery of the watershed, have played a decisive establishment of civilizations. But today, large amounts of pollutants enter the aquatic ecosystems, due to overpopulation and the expansion of industrial and agricultural activities. Among these, heavy elements are of special importance due to their stability, non-degradability, toxicity and bioaccumulation potential. Therefore, in this study, potential toxic elements ( AS, Cd, Cr, Ni, Cu, Pb, Zn) were investigated in order to determine the concentration, contamination factor and degree of contamination, geo-accumulation index, Enrichment and to detect the level of pollution caused by them. For this purpose, 21 surface sediment samples were collected based on the distribution of point and non-point pollution sources and river morphology. Samples were conditioned and concentration of toxic elements and sulfur were measured using ICP-MS at dry weight with accuracy of mg/kg and percentage of total organic carbon. Using enrichment factor and sediment quality standards (ISQGs, PEL, SEL), the level of contamination caused by toxic elements was detected. Hierarchical clustering analysis (AHC) with pearson similarity coefficient was used to identify metal elements with similar behavior in river sedimentary environments and the most important cationic adsorbent such as organic matter and clay particles using XLSTAT2018 software

In recent years, flooding of rivers has resulted in destructive implications, especially in the coastal areas. Dashtyari coastal plain is located in the southeastern of Iran. The occurrence of destructive floods has led to extensive damage to agricultural facilities, buildings, and residents of the region in recent years. Morphometric factors of the river and its surroundings land-uses and their changes in the future are effective and necessary factors in the planning of coastal plains. Remote sensing is an applicable tool to investigate the past, present, and postcondition of rivers. The GIS-Ready layers included satellite images (Landsat 5, 1987; 7, 2001; 8, 2019; Sentinel-2, 2020), and specific software (Envi 5.3, ArcGIS 10.4.1, and Idrisi TerrSet), as well as the existence and fieldwork documents, have been used to achieve the research aims. Probability values of land-use changes in 2019 were obtained based on Markov chains. Accordingly, the highest probability of changes 24.87% and 23.5% were obtained between the river and plain units, and between farms and river, respectively. Then, an automatic cell prediction map of 2019 is accomplished with the overall kappa coefficient of 95%. According to the accuracy of the output of the cellular Automata Markov model, forecasted Land use and river morphology maps for 2030 were developed. Further, possible changes in the river environment were obtained by fitting the two maps of 2019 and forecasting 2030. Moreover, bank erosion was identified in the 6 critical points along the Kajo, Dashtyari, and Bahu rivers. Finally, the destructive flood event in January 2020 in the Dashtyari region was investigated to match the results with natural events.

The method employed in this study was based on experimental research and field study. In this method, the stored radiocesium of the forest region which was supposed to be converted into Poplar plantation has been compared with the stored radiocesium of the reference region. 11 core samples were taken from reference region and then 7 core samples were selected from the transect which was a part of Poplar plantation that were taken by topographic characteristics in a depth of 25 centimeters, Having prepared the core samples according to the IAEA, they were packaged into the special Gama spectrometer containers. After that the amount of radiocesium of all samples has been measured by Bq kg-1 scale. The findings revealed that the amount of radiocesium in reference region was computed as 5894.1. Bq m-2 y-1. In the present study, soil loss rate during transect was estimated using proportional conversion models and mass balance I and II of 18.70, 22.72 and 18.64 ton / ha, respectively. These values were obtained for slope of 10-20%, canopy cover of 25% and clay loam soil under 1000 mm precipitation. This study recommended mass balance model II for estimation of erosion in changed land use areas and concluded that forest land use change to plantation due to reduction of long soil cover and plantation management by removing other seedlings and herbaceous cover increased the rate of soil erosion occurs. This process for many years has caused the erosion rate to exceed and has caused the loss of 0.1 cm of soil per year.

Rivers, as the living artery of the watershed, have caused its life and have long determined the extent and establishment of civilizations, especially in the coastal plains. The Tajan River in the coastal plain of Sari has been directly polluted by water and sediment resources as a result of industrialization, agricultural development, and towns, and villages. The aim of this study was to determine the quality of surface sediments of Tajan River in the city to sea range based on the concentration of toxic elements As, Cr, Cd, Cu, Ni, Pb, Zn and to detect the level of pollution caused by them. The sampling strategy was designed to collect 25 surface sediment samples based on the distribution of point and non-point pollution sources and river morphology. Samples were conditioned and concentration of toxic elements and sulfur were measured using ICP-MS at dry weight with accuracy of mg/kg and percentage of total organic carbon. Using enrichment factor and sediment quality standards (ISQGs, PEL, SEL), the level of contamination caused by toxic elements was detected. The results well identified the polluted and clean ranges of the Tajan River. Accordingly, the southeast and downstream of the urban area of Sari were polluted by the toxic metal of As and upstream of the urban area, and adjacent to the effluent of industrial estates to the river were contaminated considerably by the toxic metal of chromium. Finally, superficial sediments of the Tajan River along the studied range were polluted significantly by the toxic metal of Ni at a risky level. Also, Pb enrichment was proven in the downstream sediments of the urban area due to fossil fuels. The research results emphasize the effect of urban-rural pollution (surface water drainage, construction waste and rubbish), industrial and agricultural effluents and sand mines on the pollution of water resources and sediment of Tajan River.

The present study reveals for the first time the rate of soil erosion using radioisotope method in the Hyrcanian forests, which were harvested three decades ago by strip harvesting. Based on the available records, the selected area in compartment 703 of Chafroud Guilan region was selected. In order to study the soil stability in field operations, a scraper plate was used to take samples in different depths of the reference area, from 2 centimeters depth up to 30 cm (maximum penetration depth of cesium). Then, in the reference, harvested and non-harvested areas, some samples were taken by core sampler. Samples were prepared according to IAEA guidelines and then, the quantity of their radiocesium was counted in the laboratory of Atomic Energy Organization. Finally, the mean 137Cs zones of the selected samples were 5894.1 Bq/m2. Therefore, in order to achieve the desired objectives of the study, three models named as MBI, MBII, and Proportional Conversion were used to reveal the erosion rate in which it was discovered that the non-harvested natural strips had some rates of 0.2, 0.7 and 0.6 t-ha-1-y-1, while in the harvested strips the rates were increased up to 8.87, 5.80 and 4.77 t-ha-1-y-1, respectively. Accordingly, it resulted in an average soil loss of 1.2 mm in the harvested strips and 0.9 mm in the natural parts per year and after 29 years of harvesting. Consequently, they can be considered as efficient methods in studying the forest hydrology and they also showed the protective role of forests in reducing the soil erosion.

Research on methods of soil and water resources management requires technic that can and cannot be remotsensing prediction, and understanding the complex and dynamic processes and provides. Neitsch et al. (2005), stating that the model swat predicting the effects of  on the creation of management activities and the amount of sediment in the basin scale, with a variety of soils, land use and management conditions in long time interval is developed. Research inducted inside and outside Iran shows that Simulation run off and sediment on the watershed large and small with use of swat model is more efficient

Changes in the geometric shape of the river channel can be studied in horizontal and transverse views; Plan view changes in river systems based on aerial photographs or satellite imagery (using remote sensing and geographic information systems) are tracked at specific time intervals and include: channel widening and narrowing, channel simplification, braiding, meander migration, sinuosity growth, chute cut-off, neck cut-off, avulsion, simple irregularities in the bank, as well as the combination of two or more of these processes (David et al., 2016; Li et al., 2017). River channel profile changes can be mapped through the time intervals, and the most important are degradation and aggradation (Ollero, 2010; Little et al., 2013). The main objectives of this study are: 1- Investigation of geometric variations of Alamut and Shahrood rivers on the basis of field visits, geological maps and plan view mapped from satellite images (1981, Landsat 3; 1991, Landsat 5; 2002,  Landsat 7; 2009, Landsat 5 and 2015, Landsat 8) in almost certain months; 2- Estimating the rate of aggradation and degradation of the channel bed based on the survey of the profile of the channel (based on mapping) in the years mentioned at the four selected stations (Khooban Baghkalayeh, Late and Rajaee Dasht stations). The most important features used to determine the geometric variations of the channel were the extension, width, branching index and sinuosity.  
Alamut-Shahrud catchment (49° 30' to 51° 10' E and 36° 07' to 36° 30' N; 4853.67 km2 area) is one of the two Sepidrudsub-catchments and is situated in the South Caspian Sea catchment. The main outcrops of this catchment is in the eastern (upstream) zone and are composed of the Miocene terrigenous rocks, Eocene volcaniclastic rocks and some Mesozoic carbonate rocks in mid zone and Eocene volcanic units in downstream zone (Annels et al., 1977).

The most significant changes from 1981 to 2015 in 130 locations have been recorded from upstream to the outlet of the basin and include the following: Channel migration (57 locations), meander cutoff (23 locations), sinuosity growth (28 locations) and branching (22 locations).
Based on the migration of the channel, the following are observed: The maximum displacement is in the eastern (upstream) and central regions; in the central-range (Razmian), the length of channel shift occurred  about 3 km and reaches up to 575 meters. The lateral displacement of the channel in the western part is less (161 m) than other intervals and is neck cut off. The river in the eastern and central part (Khooban to Bahram Abad) is on a nearly straight path. In terms of the sinuosity, the channel has open angles and the sinuosity index is between 1.1 to 1.2. While the sinuosity angle of the channel in the western part is steep and its range is much shorter than the eastern and central parts of the river. The reason for the difference in the sinuosity pattern is the existence of two fault systems with an angle of about 120 degrees along the river course in the western part. Increasing more than three times the amount of channel shift in the central region (Rajaei Dasht-Bahram Abad, Figure 8) is also evident with the decrease of the slope of the river.This change was simultaneously happened by changing the single-channel river pattern to braided channel; the drop in water velocity as a result of slope reduction, caused the sediments to be deposited more like bars and the branching ratio has increased.

Profile changes of rivers were measured in 4 hydraulic stations; Khooban (56° 38' 47.56″ ; 36° 23' 51.23″) and Baghkalayeh (56° 29' 40.50″ ; 36° 23' 35.25″) on the Alamut River, respectively in the period from 2005 to 2014 and 1984 to 2014; and Rajaee dasht (50° 16' 46.38″ ; 36° 27' 34.98″) and Lats (50° 03' 59.96″ ; 36° 36' 36.88″) in the Shahroud River; between the years 1984 to 2014 and 2005 to 2014. Mapping cross-sectional profile was carried out during the years mentioned by Qazvin Regional Water Company. The measurements were done from the right to the left of banks in the channel.
The main goal of the study is to examine cross section, diagnosis of aggradation and degradation channel. Effective factors in these two processes can be indicated by the discharge, sediment load, bed slope and human activity. These factors are in dynamic equilibrium with controlling the morphology of the river channel, and whenever one of them increases or decreases, the river channel changes to become stable under the new conditions.
By increasing flow rate or decreasing sediment load, the capacity of river transport sediment is more than that, and this led to degradation, while decreasing flow rates or increasing sediment load led to aggradation (David et al., 2016). At Baghkalayeh Station between 1988-1991, 2000-2001, 2007-2008 and 2012-2014, discharge decreasing led to aggradation process, between the years 1992-1993 and 2002-2007, with increasing flow rate; the bed degradation process has occurred. The highest rate of bed degradation between 2002 and 2007 was followed by the highest increase in bed aggradation in 2007-2008. In the Rajaee dasht station, the trend is almost identical. In the Lat station, from 2007 to 2011, changes in the flow rate and bed height of the channel were similar, and from 2011 to 2014, the bed aggradation was evident with decreasing flow rate.
Some important results are summarized as follows:1- The most important changes in the plan view of the river channel are the channel abandont process, neck cutoff, sinuosity growth, increased branching index (ie bar migration, sedimentation and branching) and lateral migration.                                                        
2- The reasons for these changes are: migration of channel bars, changes in sediment load and flow discharge, flood, growth of the fans/mouth bar formation, changes in branching and sinuosity index, geology of the watershed.
3- The bed aggradation, degradation and channel width variation processes in the studied stations in a complex site and time unit under the influence of changes in flow rate and sediment load.

Sediment transport from continents to oceans and seas via rivers is one of the most important processes regulating river-bank stabilization, soil formation, biogeochemical cycling of elements, crustal evolution and many other earth-related processes. Shahroud catchment is a part of Caspian Sea great drainage basin, located in North of Qazvin Province; its main tributaries are Alamoutrud and Taleghanrud rivers. As a structural point of view, the study area is part of Southern-Central Alborz structural zone which is mostly composed of Eocene volcanic units and Miocene terrigenous sedimentary rocks. In this research, water and sediment discharges (2013-2014 water year), grain size and mineralogical analysis of the sediment load were studied. Cyclic variation of discharge indicate a flood-dominated river; both water discharge and sediment load are controlled by the river tributaries and lithology of the catchment. This research shows (for the first time) that suspended load constitutes (mainly silt-size grains, composed of quartz, calcite, feldspar, muscovite/kaolinite) more than 99% of the sediment load. Bed-load materials are mainly volcanic- and carbonate-rock fragments. Erosion is the main process in upstream and transport/sedimentation is dominant in the river mid and downstream.

Basatin Estuary is located in the north of the Persian Gulf and in the east of Boushehr province, which is opening into the Nayband Bay and is connected to the Gavbandi River. This estuary is considered as one of mangroves forests in the northern shores of the Persian Gulf because of its spectacular ecological condition. On the other hand, Basatin estuary is setting for enrichment of several kinds of pollutions during the recent years. Therefore, this research aimed at 1) highlighting the role of the mangrove forest in mitigation and reducing concentration of pollutions, 2) estimating the concentration of metallic and metalloid elements, in particular oil bonded and terrestrial bonded in surface and in the sediment columns of Basatin Estuary, and 3) identifying key horizons in the column sediments and their compatibility with the environment and man-made events. Therefore, a comprehensive sampling of the sedimentary faces and chemical analysis of wide range of elements (50 elements) were implemented. Totally 120 sediment samples were recorded and were analyzed using ICP-OES devices. In addition, statistical analysis was carried out to reveal relationships between similarity or dissimilarity elements. The results approved the research hypothesis, and e.g. showed that changing in the estuary mouth in 1991 has resulted in limitation of hydraulic circulation of tidal currents and caused a severe increase in sediment accumulation, followed by covering aerial roots by sediments and finally drying of mangrove trees. This process has a direct role in the enrichment of heavy metals in the environment. Furthermore, the uppermost layer of sediment column (0-25 cm) has experienced moderate to high degrees of pollution by petrochemical industries. This layer was significantly enriched by Zr, V, Ti, S, P, Ni, Mn, Li, Cr, Co, Ce, Cd, Bi, Ba, as elements. Finally, time correlation of key horizons and environmental events showed that the average rate of sedimentation in the estuary Basatin fluctuated between 1.8 and 2 cm per year.

IntroductionThe Reeg estuary is an important coastal sedimentary environment in the north of the Persian Gulf that is located at the west of the Boushehr Province (Gharibreza, 2005). This basin shows morphology of the bar built estuary and includes three main sections of riverine, lagoon, and marine which is separated from land by the fossil beach. The Reeg estuary is an example of a retrogressive coast that is emerged by sea level fall since Late Quaternary (Gharibreza et al., 2002; Lak et al., 2010). This estuary might be a suitable coastal environment to collect carbonate mud and calcareous oolitic sands assuming similarities between south and north of the Persian Gulf. Determining of Reeg Estuary sediment sources especially carbonate mud and oolitic sands and identification its sedimentary facies were the aims of present research.
Materials and MethodsA comprehensive sediment sampling plan and laboratory analysis were implemented to test the research assumption. Forty-eight sediment samples were taken from different sedimentary facies of the sink and source areas. Thin section of 24 sandy texture samples of the sink and source areas were studied by binocular microscope to identify source of coarse-grained sediments. Composition of sediment was studied using Folk and Ward (1957) method. Distribution of sedimentary facies was studied using geographical information system tools which is widely used around the world (Heap, 2004).
Results and DiscussionCalcimetry tests showed that carbonate content of fine-grained sediments in lagoon section is more than 50%, which was emphasized to suitable chemical conditions for accumulation of carbonate mud. The mean content of the rock fragments, feldspar, and quartz particles were obtained 77±11%, 14±8%, and 9±6%, respectively. Resultant data showed significant profusion of calcareous rock fragments in sediments in both sink and source areas, which represents the Calclithite class of composition. Results also revealed that oolitic sands are the main constituents of marine facies (≈ 90%) particularly along the recent barrier island. In addition, Bakhtiary and Aghajari formations and coarse-grained strata of old and young terraces are the origin of coarse sediments which have been deposited in the Reeg Estuary. Once again, capability of the northern Persian Gulf's coastal sedimentary environments for deposition of carbonate sediments like as what has reported from the southern coasts was proved by present research.
AcknowledgementThe research was supported by Soil Conservation and Watershed Management Research Institute (SCWMRI), Tehran, Iran. The author gratefully acknowledges all academic staffs of coastal protection department for their helps on the implementation of this research.

Rural and urban areas are annually encountering flood hazards due disregarding to river regime and topographic characteristics. The objective of present research is the recognition of human settlements, which are subjecting to flood hazards using Topsis-AHP model. Outcome of this model is mapping of the study area in terms of flood hazards and identifying of the best location for development of human settlements. The total of nine natural factors that are contributing in flood event was used in this model and flood hazard map of Rude-shoor river basin was developed using geographic information system and ArcGIS 10 software. Resultant data was checked by field observations and results of previous studies. Results showed that 30 villages at north and south of catchment are located in areas with very high and high risk of flood because of their topographic location. The Ci index for very high to high risk of flood were calculated to be 0.993 and 0.528, respectively. The total of 36 % of catchment area were classified in very high to moderate risk of flood, which point out that the study area is encountering severe flood hazards. Present research is revealed capability of Topsis model in sketching of river buffer zone in the study area. In addition, application of Topsis model and method of this resaerch is firmly recommended to be used for planning of flood hazards for human settlements at other parts of Iran.

Management of deltaic water resources is one of the basic necessities of Iran’s coastal area, which is highlighted in the present research. Recycling and distributing discharged water from a river mouth on the deltaic plain are the main steps of this management plan. Accordingly, this plan provides a good opportunity for land reclamation, agriculture, aquaculture and tourism. Indeed, this plan was obtained after studying Zohreh River Delta in terms of river regime, sedimentary facies, geomorphology and quality of soil horizons. Measurements of river and tidal currents and application of numerical models are preconditions of achieving such a plan. The most important parts of this plan are tidal inlets and a freshwater lake with a capacity of 25 million m3, which will be retrieved during a few days in a wet season. In total, 2,480 ha of land reclamation, 30,000 tons of wheat, and 198 ha of other land development projects will be obtainable after implementation of this multidisciplinary management plan. Such a management plan is introduced as a solution for water shortage in Iran’s coastal areas and is also compatible with other deltaic plains of rivers such as Karun, Heleh, Mond, Kol and Bahookalat.

Geometrical parameters and river morphology are the main properties of each river which are used for river training، management and protection projects. So approaches to estimate these characteristics of Zohreh River are the main scopes of this research. Zohreh River as one of the permanent river of Persian Gulf basin has 64 km length in Hendijan delta and 169، 90 and 12 m3/s as maximum، average and minimum discharges respectively. Mean High High Water (MHHW) level is 2. 7 m that penetrates 17 km from river mouth upstream. Zohreh River banks are consisting urban، industrial، commerce and fishery activities which are sensitive to any changes on river regime and morphology parameters. Necessity of determining Zohreh River morphology and its changes led us to do research using GIS and field observations methods. Aerial photos (1967)، satellite images (TM، 1989 and ETM+، 2002)، topography map، previous studies and Ilwis and AutoCAD softwares were the materials used in this research. Results have shown two river cut offs which occurred since 1967 and channel meandering increased from 43 meanders to 48. Also sinuosity coefficient decreased from 3. 59 to 3. 06 and mean radius curvature and wave length increased 26% and 0. 06% respectively. According to Korins classification and mean central angle of Zohreh River، it is fallen in extreme developed meanders morphology category.

Coastal zone of Khuzestan Province, which has an area of 1359832 hectare, is covered by various coastal (i.e. estuary, lagoon, delta) and continental (i.e. river and alluvial fan) environments. In this research, TM (1988) and ETM+ (2000) satellite images were used for recognition and differentiation of coastal environments. This study is based on combination of visual and digital image analysis in a GIS environment. The best images were formed by combination of 432 bands of TM and 431 bands of ETM+ sattelites. Polygon maps showed that most part (>70%) of region is covered by delta, lagoon and tidal flat environments.

In this research sea-level changes of Kiashahr-Dastak coastal zone in a 26 years old interval (1968-1994) were studied. The arial photographs were studied in a GIS environment utilising Ilwis software and considering field evidences as well as grain- size analysis. The results were shown as erosion and sedimentation maps in this interval. Changes in the position of coast line is indicative of regressive coasts (sedimentation-dominant zones) in the areas where the rivers run in to the sea and transgresive coasts (erosion-dominant or drowned zones) in the eastern part of Sefidrud delta, particularly the northern part of Dastak district. GIS based studies and field investigations show that sea level rise caused progration of coasts with an average of 14 m/year and in the sedimentation area had regreted with an average of 11.3 m/year. In addition, significant changes are also seen in the coastal facies in this time interval; among them avulsion of the Sefidrud and changes in the distribution of facie are the most important

Maharlu basin with an area of 4274 km2 is located in Fars province. The Precambrian Hormoz series and the Quaternary units are the oldest and youngest rocks in the basin, respectively. Spans of outcropped rocks, covering from the Cretaceous to Quaternary, are carbonate sediments of deep to shallow marine facies. These sedimentary sequences include large and small stratigraphic gaps in the form of disconformity and sometimes nonconformity. More than 50% of the basin area is covered by the Quaternary sediments. The region is mainly composed of sedimentary deposits. Six factors of rock unit weathering: rock resistance, weathering condition, fissure and joints, slope, climatic conditions and vegetation covering are the main factors for estimation the sensitiveness of geological formation to weathering resulted from laboratory and field tests.‍‍ 12 formations Cropped out in the basin. To evaluate erodibility, BLM method is used to measure the weathering sensitivity of soft geological formations. The acquired data and the formations with their sensitivity to weathering are combined into GSI and finally the map of sensitivity of different geological formations to weathering of Maharlu basin was prepared. The data resulted from laboratory and field tests indicate that Asmari-Jahrum formation and the Quaternary alluvial fan possess lesser sensitivity and higher resistance to erosion and Hormoz series, Pabdeh-Gurpi formation, Razak formation and Aghajari formation are critical to weathering. Bakhtyari formation, Bangestan formation, Tarbur formation, Sachoun formation, and young and old Quaternary deposits can be placed in group of moderate to weathering.

Chabahar Bay is located along the coast of the Oman sea in Sistan province in southeast of Iran. This area is a part of coastal Makran zone (one of the geological zones of Iran) that had undergone sea level changes along the Late Quaternary. Multiple sedimentary sequences and several paleoshorelines were formed due to these processes. In this investigation, 21 paleoshorelines were recognized by using GIS analysis. In the borehole at the north of Chabahar Bay, 14 layers were discovered that could be related to Late Quaternary sedimentary sequences and correlated to glacial and interglacial periods. All layers of borehole were analyzed for grain size, sedimentary structures and fossil contents. Four radiocarbon measurements have been made on the lowest and uppermost marine layers of borehole and on C7 and C21 of paleoshorelines. The lowest layer of borehole has 17,600 14C yr B.P, related to Cataglacial or Flanderian transgression, outcropped at 15 m height and 5,300 m distance to present shoreline. Sedimentary sequences have shown 4 transgressions and retrogressions occurred from Cataglacial to the present. On the other hand, from 4,690K40 yr B.P, 20 paleoshorelines have been formed, which the duration of each may be about 230 years.