فهرست مطالب ناصر حاجی زاده ذاکر

In this study, the relationship between dissolved oxygen reduction in the Gulf of Oman and changes in effective factors such as temperature and thermal stratification, exchanges with nearby water bodies, biological activities, chlorophyll-a concentration, and primary production was studied. The data used in this research were extracted from the measurement data available on global sites such as the World Ocean Atlas and SeaWiFS and MODIS satellite images. Comparing the average annual DO profiles in the Gulf of Oman showed a decrease in the upper 1000 m layer in 2010 compared to 1960. The DO reduction in the surface mixed layer was 0.4 mg/l and reached 3.7 mg/l at 100 m depth. At depths more than 100 m, the amount of change decreased and reached 0.1 mg/l at 1000 m. Due to the deoxygenation, the thickness of the surface layer with DO˃2 mg/l decreased from 150 m to 80 m. The results demonstrated that the drop in DO in the surface mixed layer was consistent with the decrease in gas solubility caused by the temperature increment in this layer. Regarding the severe reduction of DO in the layer below the surface mixed layer, it was shown that the strengthening of thermal vertical stratification and intensification of thermocline (0.01°C/m increase in thermal gradient) were the most important factors.

Coastal towns have specific positions due to the possible utilization of sea and attraction tourists. Finding useful methods of sewage disposal at lower costs and higher efficiency and also expandable in terms of the capacity of coastal towns is very important. Releasing residential sewage of Chalous city into the Caspian Sea makes marine environment a source of raw wastewater and the receiving water body affected by entering these contaminants. The contaminants cause to pollute fishes, sediments and coastal waters and then will transmitted to humans through the consumption of contaminated marine organisms and pathogens or by swimming. Many of researchers and experts believe that secondary treatment of wastewater, needs a lot of costs and energy and sludge disposal and production should be continuously monitored. But with proper planning of drainage system for the sea, we can discharge large amounts of sewage into sea with no need to treatment maintenance. Oceans, seas and Great Lakes have high self-purification capacity to absorb sewer of coastal towns. There are many types of wastewater discharging into the sea include directly discharges onto the beach, discharges with a short outfall with likely contamination of recreational waters and discharge with an effective outfall designed so that the sewage is efficiently diluted and dispersed and does not pollute recreational areas. Dilution of the wastewater into the sea have three-phase including near-field, far-field and long-term flushing. Generally, the near and far field dilution mechanism strictly disagree that they act separately as a independent treatment service. The outfall system typically consists of tunnel or pipeline, diffuser and ports on the diffuser; in this system the basis is the dilution of wastewater without any problem for the marine environment. Prediction of near field mixing requires understanding of the dynamics of jets, plumes and buoyant jets; a jet is a flow driven by the source momentum flux only, a plume is driven by the source buoyancy flux only and a buoyant jet is driven by both momentum and buoyancy fluxes. Discharges from an outfall diffuser have both momentum and buoyancy and are therefore buoyant jets, but the buoyancy flux is usually dominant and ocean outfall discharges can often be approximated as plumes. In this study, the use of outfall as sewage disposing system in the city of Chalous that is located near the southern coast of the Caspian sea, has been assessed in term of environmental. Mathematical models are now widely used to predict the fate and transport of ocean discharges. This is not possible to simulate these types of discharges with one overall omnibus model, because of the very wide range of lengths and times scales for various mixing processes. Therefore linked sub-models of the various phases are usually used. In general, assumptions used in modeling the dispersion and dilution of waste water include the incompressibility of flow, the pressure is hydrostatic and molecular scattering is ignored. The theory of mixing zone and near-field models are different by far-field models and includes the length scale, entrainment and CFD models. For far-field the hydrodynamic models have been developed in past few decades and are being used increasingly to predict the fate and transport of marine discharges. There are three basic equations for the discharge of sewage into the sea through an outfall include: mass flux, momentum flux and buoyancy flux that using dimensional analysis leads to considerable analytical simplification and to useful equations for predicting plume behavior and dilution. One of the common near-field models is CORMIX that is provided for analyzing the discharge of various types of discharge to marine waters. CORMIX is a comprehensive software system for the analysis, prediction, and design of outfall mixing zones resulting from discharge of aqueous pollutants into diverse water bodies. It contains mathematical models of point source discharge mixing within an intelligent computer-aided-design (CAD) interface. Its focus is environmental impact assessment and regulatory management. CORMIX has been developed under several cooperative funding agreements between U.S. EPA, U.S. Bureau of Reclamation, Cornell University, Oregon Graduate Institute (OGI), University of Karlsruhe, Portland State University, and MixZon Inc. during the period of 1985-2007. The major emphasis of the CORMIX system is on the geometry and dilution characteristics of the initial mixing zone including compliance with regulatory constraints as well as predicting the behavior of the discharge plume at larger distances. However, this system also has capabilities to predict the wastewater over long distances in the far-field. CORMIX contains three core hydrodynamic simulation models includes: Simulation models for single port discharges (CORMIX1), Simulation models for submerged multiport diffusers (CORMIX2) and Simulation models for buoyant surface discharges (CORMIX3). In this paper the CORMIX2 has been used for predicting and modeling the discharges from an outfall diffuser; the following items must be respected in the design of a multi-port diffuser: port and nozzle diameters (not too large to cause the sea water to enter diffuser and not too small that waste energy and increase pumping costs), nozzles angle to the seabed in a way to flow horizontally into the water body because of optimal dilution and the outlet port shape of nozzles be such that not to cause friction in the direction of wastewater disposal and preferably be circular. Factors of water contamination are nutrients, bacteria and pathogens, toxic, chemical, organic, heavy metals and suspended solids. Pathogens are the most important factor to design the outfall and can be controlled by initial mixing, diffusion and destruction by sunlight. California ocean plan is an instruction to a successful discharge of sewage to marine waters without complications for the environment. This plan limits the level of water quality such as bacterial, chemical and physical properties and also considers some limitation for sewage. The most important indicator bacterium in sea water and natatorium is Enterococcus. According to the California Ocean Plan, USEPA limited levels of coliform bacteria Enterococcus for the 30-day geometric mean to 35 units per 100 ml. Also maximum of coliform units in the discharged wastewater to the sea is limited to 1000 units per 100 ml. Discharges near environmentally sensitive areas such as coral reefs or shell fishing beds should be avoided. If the diffuser cause rapid dilution and dispersion of the effluent and is positioned so the waste field transport to critical areas is minimized, only the preliminary wastewater treatment such as milliscreening may be needed. To choose a convenient location for an outfall, the various parameters are effective includes water depth and the slope of the seabed, type and direction of currents, swim areas, regional water quality, concentration of population and entry of rivers water into the sea; So given the above parameters, three routes along the coast of the Chalous city proposed and investigated and the proper route and discharge depth chosen during a process of trial and error. The worst dilution conditions such as no currents and strongest density stratification must be considered for designing an outfall. Therefore to obtain the worst dilution case, the model is run for different seasons. Thus, outfall designing takes place based on specifications of the summer season that currents are minimal and the density difference is the highest value. Diffuser geometrical design is plotted using CorSpy that is one of the CORMIX post processing tools. The diffuser has the length of 50 meters with eleven ports that each port has a T-shaped nozzle with 25 cm height and 50 cm from the seabed. Due to strong density stratification of sea in the summer, the discharged sewage doesn’t reach to surface water and becomes stuck in the terminal layers. The distance between the source of discharge and where the plum meets bank is about 6500 meters and due to average currents that is 0.058 meters per seconds, the time of reaching to bank is about 31 hours that is more than 24 hours considered and there is enough time to kill bacteria. According to the results of CORMIX the bacteria reach certain standards within regulatory mixing zone and there are no worries about natatorium area that is the thousands of meters away. Because of poor density stratification of sea in winter, the discharged sewage reaches to surface water and therefore the 100 value of dilution must be checked at that water level; By CORMIX modeling the distance between discharging sewage and where it reaches to surface level is about 120 meters and the dilution value of is 250. According to the results of modeling, discharged wastewater meets the bank with a distance about 10 to 25 kilometers from the source with different ambient currents that is adjacent to residential and swimming areas but due to its arrival time is more than 24 hours, so there is enough time to kill bacteria. The model also was tested for the reversal ambient current that is usually occurs on cold days and the plum meets the bank with a distance about 10 to 20 kilometers from the discharging source with different ambient currents. The results of the modeling in terms of average monthly current in summer and winter show that the value of plum dilution when it reaches to water surface in winter and the time of meeting plum to bank from the discharging source in summer, are two main parameters for designing of Chalous city outfall. Discussion of The project goal was to design an efficient outfall that have features such as proper drainage location, sufficient diffuser length, proper discharge depth, safety purposes, economic, and trustworthiness of the effects of biological, chemical and physical. The outfall was designed in the worst environmental case modeling with almost no currents and maximum density stratification that occurs in summer and to ensure the proper functioning of the outfall, other conditions were also modeled. Desired location for installing outfall is chosen according to the parameters like beach slope for decreasing outfall pipe length, flows and wastewater fate in the far field so as not to reach swimming and tourist areas and pollution from streams and existing municipal waste. The results of the model show that in the first movement, sewage discharge is diluted more than 100 times in a few minutes and within 10 meters of the discharge location, all pollutants comply with environmental conditions and adherences to the strictest standards. This amount of dilution is more than a lot of secondary treatments ability. The major environmental advantages of the project are protect groundwater from contamination by sewage, eliminating the direct discharge of wastewater into the Caspian Sea and thus improve the quality of sea water, eliminating the harmful effects caused by sewage sludge dumping and reduce energy consumption and thus produce less heat and pollution. The results of this study indicated that the use of marine outfall in the city of Chalous with some considerations such as preliminary treatment prior to discharge is desired option. In addition, the results indicated that outfall not only eliminates the environmental problems of wastewater disposing, but it is the most economical method of sewage disposal.

Persian Gulf is a water body at the margin of Indian ocean which makes way to Oman Sea and Indian Ocean through the Strait of Hormuz with the minimum width of 56 km. Specific condition of the Persian Gulf such as high evaporation, high salinity, aqueous species diversity, fisheries value and especially oil sources of the area, which have extra importance in the world, have made it a sensitive and strategic area. Marine environment of the Persian Gulf suffers severely from oil pollution. Oil extraction and transportation together with the effluent dischrges from the coastal cities and oil refinneries are among the major sources of oil pollution in the Gulf. Kharg Island is a coral anticline in the Persian Gulf located within 28 km of the southern coasts of Iran. This island has a length of approximately 8 km and a width of approximately 4 to 5 km. The coastal environment of the Kharg Island is rich with corals. The corals are the host to many types of local fishes of the Persian Gulf. Kharg Island contains the most important and also the biggest crude oil export terminal of Iran. More than 90% of Iranin oil exportation is conducted through the island. In addition, many other oil related activities including storing and filtering of the crude oil are performing in the island. Hosting extensive oil related activites during the past 50 years has subjected the marine and coastal environment of Kharg Island to huge amount of oil discharges from different sources icluding Oil Tanker accidents, leakages at the oil term inals, discharge of oily effluents from crude oil stores and oil refineres. However, surprisingly, there are only a few studies conducted on the oil pollution around the island. In this paper, the oil pollution and its origin in the near shore coastal sediments of the Kharg Island are examined and discussed. This is conducted by using the analysis of the concentration of hydrocarbones in the sediment samples collected early 2012 from 11 points around the island. Near shore sediment samples were collected at 11 points around the Island. The stations were selected in a way that they cover the whole parts of the island's coastline. The samples were also more concentrated near the oil terminals. All of the samples were taken near the coastline at knee deep water points in low tide condition. About 200 to 300 grams of wet sediments were taken from the top 5 centimeter of surface sediment and was poured into boron silicate vial which was washed by washer material, hot water, acetone solution and distilled water and had a lid of polyethylene. The collected samples were packed and protected for transferring to laboratory using the USEPA-sw-846 standard method. The standard method of American Association of Environmental Protection (USEPA-SW 846#3540C) named SOXHLET has been used for preparation of the samples and extraction of petroleum hydrocarbons from them. The samples were passed through a 63 micron sieve (<63) before the lab analysis. A gas chromatography device (GC-FID) Model VARRIAN was used to determine the concentration of Total Petroleum hydrocarbons (TPH) and aliphatic compositions in the sediment samples. In addition, the concentration of petroleum normal alkanes with different numbers of carbons (n-c 10, n-c 35) was measured. Concentrations of total petroleum hydrocarbons (TPH) in surface sediments TPH concentrations are represented by a diagram in surface sediment samples collected along the coastlines of the Kharg Island. The concentrations varied from a very low amount of 1 􀂗g/g to very high amount of 5624 􀂗g/g. The highest TPH concentrations were observed at stations 2, 3 and 4, at 5624, 1660 and 4186 􀂗g/g, repectively. These stations were located on the eastern coast of the island near the T shape quay, next to the major crude oil export terminal. The results indicate that the leakage from the loading activities have highly polluted the coastal area around the T shape quay. Stations 9 and 10, where are located near Azarpod Jetty on the west side of the island, have relatively high TPH concentration, 141 and 75 􀂗g/g, respectively. The oil pollution in this area is resulted from the oil leakage in Azarbad oil terminal and also tanker incidents. The lowest amount of TPH concentration was observed in stations 1, 7, 8 and 11 up to <1, <1, 2 and 32 􀂗g/g, respectively. Station 1 was located in the south of the T shape quay and is somehow close to this oil terminal. However, considering the dominant direction of the wind waves on the eastern coast, the sediments in the position of this station were not affected from the oil discharges near the T shape quay. Staions 7 and 8 positioned on the northern part of the island are far from the oil pollution sources near the oil terminals and were not affected from these sources. TPH concentrations at stations 5 and 6 were 78 and 232 􀂗g/g, repectively. The concentrations in these stations are much less in comparison with the station 2, 3 and 4 adjacent to the T shape oil terminal. However, the T shape quay seems to be the source for the oil content of the sediments at these stations as well. Commendatore and Esteves (2007) dividedc oastal areas into three categories from the view point of oil hydrocarbon rate: low concentration (􀂗g/g < 10), low to average (10-100 􀂗g/g) and average to high (100-1000 􀂗g/g). Readman et al, (2002) considered the sediments with concentration above 100 􀂗g/g as polluted. Tolosa et al, (2004) considered the sediments with concentration above 500 􀂗g/g as severe polluted and the ones with concentration less than 10 􀂗g/g as non-polluted. Regarding to the above criteria the sediments on the eastern part of the Kharg Island adjacent to the T shape quay can be considered as highly polluted. The polluted area extends to the north of the T shape quay along the east coast to the positions of stations 5 and 6. On the west coast of the Island the polluted area are limited to the vicinity of the Azarpad Jetty. Apart from the above mentioned areas, the shallow water sediments around the rest of the Kharg Island in most of the west coast and in the north and south of the Island can be considered as not polluted. The origin of aliphatic hydrocarbons (AHC) in Kharg Island sediments Hydrocarbons in sediments might be originated from fossil petroleum origin resulted from human activities or originated from biological activities of Algae, Planktons, Bacteria, marine animals and terrestrial vascular plants. In this part, the origin of hydrocarbons in studied region was determined through developing a set of present indices and the position ofo bservance pollutants in each of the stations. In Kharg Islandby regarding to oil activities in this area, crude oil is considered as the first oil pollutant. Relative abundance of normal alkanes with different numbers of carbons or predominance of the specified alkane in sediments can be the index of certain types of oil hydrocarbons presence in sediment samples. Therefore, the presence of 18 carbons normal alkane (n- C18) in sediment samples shows the oil origin of observed hydrocarbons (Clarke and Finely., 1973). Odd carbons normal alkanes with low number of carbon atoms such as 17 carbon normal alkane (n-C17) is identified as the index of phytoplankton hydrocarbons presence (Tolosa et al., 2004). Normal alkanes with odd numbers of carbon 27, 29 and 31 (n-C31, n-C29 and n-C27) are introduced as the index of plant waxes presence with land organic plant origin (Tulloch, 1976). N-C16 index, which is equal to n-alkanes/n-C16, is the number less than 15 for polluted samples by fossil petroleum and the number more than 50 for polluted samples by biological hydrocarbons (Clarke and Finely., 1973). Carbon priority index (CPI) is defined such as equation (1) with Boehm and Requejo in1986: CPI= 2(C27+C29)/ C26 + (2C28) + C30 (1) The CPI index is about 1 for petroleum hydrocarbons, while it varies from 3 to 6 for vascular plants and fornon-polluted sediments by fossil oils (Colombo et al., 1989). The other index is the Odd/Even index, which is the ratio of odd numbers of carbon atoms to even numbers. This ratio varies about 1 for petroleum, while for plant waxes; alkanes with odd chain are 8 to 10 times more than alkanes with even carbon chain. In some diagrams we show normal alkanes concentration profiles with different numbers of carbon atoms in stations of the study area. As these profiles show, in stations numbers 2, 3 and 4, which are eastern dock of island (T shape quay) and in stations 8 and 9, which are on the proximity of western jetty (Azarpod jetty), 18 carbons with normal alkane has the most rate in compositions and this shows the presence of oil hydrocarbons. At stations number 7 and 10, 17 carbons with normal alkane has the most rate and these rates show the presence of phytoplankton hydrocarbons in these stations. At stations 1, 5, 6 and 11 by increasing the distance from oil docks placed on island, the rate of n-C17 concentration is more than n-C18 and this indicates that in these stations present hydrocarbon in the sediment has biological origin. By regarding to insignificant concentration of earth alkanes (n-C27, n-C29 and n-C31) in general profile of normal alkanes, there are no hydrocarbons with land vascular and organic plants in surface sediments of the study area. Because of the plant poverty in Kharg Island, lack of presence of terrestrial plants hydrocarbons is observed. The range of n-C16 index, in sediments of this region is 6.36 to 332.4. This rate in stations 2, 3, 4, 5, 8 and 9 are less than 15 and typical of the polluted sediments of this region from petroleum. However, this rate is more than 50 in other stations (stations 1, 6, 7, 10 and 11), this means the pollution of sediments in these regions is from the type of biological hydrocarbons. The other index is “CPI” which is between 0.75 and 5.7, and from its results in stations 2, 3, 4 and 10, we can find out that in all the point near the oil quays of Kharg Island, there are oil sources in coastal sediments. In other stations, the rates of these indices show that their hydrocarbons have biological origins. Some stations including stations number 1, 5, 6, 7, 8 and 11 have not oil pollutions. Evaluation of observing hydrocarbons concentrations based on ratio of alkans with odd carbon numbers to evens shows that this ratio varies in a range from 0.8 to 7.36. These rates are equal to one in stations No. 2, 3, 4, 5, 8 and 9.In other stations including 1, 6, 7, 10, 11 this quantity is more and there are high concentrations of old normal alkanes which suggests that there are biological sources with plant waxes for hydrocarbons. Therefore, general position of observed hydrocarbons in sediments of Kharg Island coastline suggests that there are fossil oil origins in the proximity of oil jetties in which high oil activities are performing and there are biological and natural origins in other stations of the island. The pollution of the sediments in the studied area from the total petroleum hydrocarbons (TPH) was investigated by oil hydrocarbons analysis in coastline sediments of Kharg Island and also by comparative analysis of these concentrations with the present guidelines and standards. The results of the studies based on the total petroleum hydrocarbons concentration indicate the high pollution in some stations and very low to average pollution in other stations from oil activities resources. At stations near to the eastern and western docks (particularly near T shape quay), this rate is high and by getting away from oil terminals, this rate is reduceing.In northern and southern regions of island, this rate also reaches to the minimum. Using the relative indices, it has been shown that the observed hydrocarbons in studied sediments have natural phytoplankton origin in farther points from jetties; in addition to havingoil origin in most of the east and west stations and near the oil terminals.

The Gonu tropical cyclone is the strongest storm in the Arabian Sea in which has cause damage in the Iranian south coastlines. The aim of the current paper is to numerically simulate the wave’s characteristics as well as the storm surge during the Gonu event by employing the SWAN wave model and the GETM hydrodynamic model. The simulation duration is one month i. e. from15 May to 15 June 2007. The wave characteristics are compared with the measured data in three measurement stations. The results show that the wave characteristics are reasonably simulated during the Gonu storm event so that the significant wave height is reached up to six meters and the corresponding height was four meters، respectively، outside and inside the Chahbahar bay area. The results show that the storm surge has reached up to 50centimeters in the Chahbahar coastlines which are corresponding to the 6th day of the Gonu storm.

Education and community preparation are one of the most important components of disaster management. This phase of the disaster management cycle can play a significant role in disaster risk reduction due to its serious effect on community. So far, because of this importance, many activities have been undertaken in various countries for disaster education and public awareness. This study aims to assess and evaluate the public awareness of tsunami disaster in Chabahar port in Iran by using questionnaires that were distributed among three various groups of respondents including: residents, school children and governmental officials. Data have been collected by field technique through simple random sampling. According to the results, only 85% of people were familiar with the term of tsunami. However, a correct definition did not provide for this phenomenon. About 59/4% of respondents were unaware of existence of this system in Chabahar. About 57/4% of people were obtained their limited information about tsunami from mass media including television, newspapers, Internet and etc. Deaths and injuries were the greatest concern of people in tsunami. From the viewpoint of Chabahar people, the most important biological effects of tsunami were its harmful effect on beach and then its impact on coastal animals and plants.The results has shown the lack of awareness and knowledge of people in the region especially women. Based on the obtained findings and analysis of the results, few suggestions and strategies are proposed by the authors for raising public awareness of probable tsunami disaster in the future as well as to promote novel disaster management methods.

Direct discharges of municipal and industrial waste waters into water bodies through marine outfalls are considered as a common way to dispose the generated waste in coastal zones. Marine discharge, intensifying flow mixing and entrainment, decrease the concentration of polutant up to accepted concentration and meet the guideline values and to make possible continues discharge of flow into matine environment. During last years due to quick development of coastal desalination plants, surface discharge of preduced salty water into seas and oceans has increased significantly. In this study, releases of dense jets from surface rectangular channel into stagnant bodies are experimentally studied. The location of flow plunge point, impact point and discharge ultimate dilution were drown out by a digital video technology. In addition, using some conductivity probes located in ambient floor, waste filed dilution in flow impact point and discharge ultimate dilution were identified. Finally the obtained results were plotted and explained along with some diagrams to show flow non-dimensional behavior. The results showed that the properties of flow are changing directly with ambient water depth and discharge initial fluxes.

Ports’ activities could result in oil spills occurrences and oil pollution in different ways including the discharges of ships’ oily wastes, discharges of oily ballast water and leaks at oil terminals. In this paper, using the results of the analyses of the hydrocarbon compounds in the samples collected from the sediments in the Anzali Port in the Caspian Sea in Iran, the levels of oil pollution in the sediments, in terms of Total Petroleum Hydrocarbons and Petroleum Aromatic Hydrocarbons, are studied. Also using a number of existing biomarker profiles, the sources of aliphatic hydrocarbons were investigated. The concentration of Total Petroleum Hydrocarbons ranged between 7.6 to 29 mg/kg indicated that oil pollution content of the sediments in the area is at a low to medium level. Also the concentrations of PAHs in the sediments were very low (0.62 – 6.12 ng/g). This indicated that the sediments sampled in the study area can be considered unpolluted in terms of aromatic hydrocarbons. Analyses of the samples using a number of biomarkers showed a combination of natural (marine and terrestrial) and petrogenic hydrocarbons in the sediments in the Anzali Port area.

In this study the results of the experiments conducted in surface discharge of negatively buoyant flows in stagnant and non-stratified body are presented. Geometrical behavior of flow have been studied by simulating of discharged in a dark room and digital possessing of the photos. To determine the mixing behavior of flow the data obtained from 20 conductivity probes located along the trajectory of flow were utilized. Flow concentration profiles, flow self similar trajectory, variation in flow width and changes in flow dilution are the flow characteristics that were studied here. Regarding flow self similar properties the non dimensional behavior of flow will show similar behavior for different conditions of discharge. To have a comparative scale the experimental results were compared with the behavior that formerly reported for submerge horizontal discharges of positively buoyant flows. The analysis of flow behavior in these two discharges showed that despite the fact the flow general behavior is similar, geometric and mixing characteristics of flow in surface discharges are different from the those observed in submerge discharges. In surface discharges flow protrudes more in comparison to submerge discharges. The changes of flow width and dilution were also different from the one reported for submerge discharges.

Surface discharge of dens jet as a common way for disposal of produced waste water in coastal areas is strongly influenced by the hydraulical and physical fissures of discharge stream and ambient water. In the current study, considering different mechanisms of flow in surface discharge of negative buoyant jets, dominated regimes are studied. Using Length Scale (L.S.) method and utilizing an experimental set up which are merely designed for this studies, different flow regimes were experimentally simulated and its behavior were investigated. As a result of this study, the observed criteria for free jet regime, shoreline attached jet regime and intruding upstream plume in the case of surface discharge of dens jets were précised and their ranges of diversity in the form of dimensionless diagram were developed. The axis’s of this diagram are a couple of dimensionless parameters that formed by the flow variables where each shows classification criteria in the boundaries of diagram. Finally, extracted criteria as a separator of these regimes were used to develop a tree-like classification scheme in surface discharge of dens jets. In this method, through identifying the range of flow variables in occurrences of each regime and sub regimes, coming prediction of flow characteristics by empirical equations will easily be possible.

The main goal of this study is to increase the software capabilities of Iran towards the development of a tsunami warning system for its southern coast bordering the Indian Ocean. The devastating tsunami of 26 December 2004 in the Indian Ocean region emphasized the necessity for development of tsunami warning systems for the world’s vulnerable coastlines, especially for those neighboring the Indian Ocean. Studies showed that there are two main tsunamigenic zones in the Indian Ocean region, namely the Sumatra subduction zone in the east and the Makran subduction zone at the northwest of this ocean. The Makran subduction zone is located offshore Iran and Pakistan and produced some destructive tsunamis in the past. The most recent tsunami in the Makran region occurred on 28 November 1945 which claimed more than 4000 lives along the coasts of Iran, Pakistan, Oman and India. As the southern coast of Iran is at risk of tsunami from the Makran subduction zone, Iran is committed to work towards the development of a tsunami warning system, and to cooperate with the countries in the region in this field. All activities towards the development of a tsunami warning system can be classified into two categories: 1) hardwares like tsunameters, tide gauges, seismic networks, and etc., and 2) softwares. Numerical modeling of tsunami is among the second group and is a vital part of any tsunami warning system. Here, we discuss the modeling of tsunami generation and propagation. At first, the algorithm for tsunami generation modeling is presented and then, the generation phase of a possible tsunami in the region was modeled. The results of generation modeling were compared with international experiences. In the next section, the propagation of tsunami was modeled using a well-validated international numerical model for long waves. Results of the tsunami generation modeling showed that in the case of an earthquake with a moment magnitude of 8, the maximum vertical uplift of the seafloor will be about 1.5 m, and an area with the dimensions of 150 and 250 km will be deformed due to the earthquake. Tsunami propagation modeling showed that the first tsunami waves will hit the nearest coastline within 15-20 min after the earthquake. The maximum tsunami wave height was estimated about 3 m. It is showed that how the results of the numerical modeling of tsunami can help to develop a tsunami warning system. Our preliminary investigation shows that at least 891 case-scenarios should be simulated to develop the tsunami warning system in the Makran region.

Marine environment of the Caspian Sea, due to extensive human exploitation and discharge of large magnitudes of urban, industrial and agricultural waste, is under extensive pressure and human wastes threaten marine life and ecosystem of the sea. Therefore, there is a substantial need for a good understanding of physical and chemical characteristics of the Caspian waters. However, the data available in this regard, in particular in the Iranian coastal waters, are very limited. This paper presents distribution and seasonal variations of pH over the southern Caspian Shelf adjacent to Iran. The pH data were collected down to 200m depth in two areas in east (off Babolsar in Mazandaran) and west (off Kiyashahr in Gilan) of the southern coast of the Caspian Sea. In summer, when the surface water temperature was highest and the strongest seasonal thermocline existed, the maximum value for pH was observed. In this season, pH had a value of 8.35-8.4 at the water surface and reduced to 8.2 at 80-m level and deeper waters. In autumn, when the surface layer was deepening and seasonal thermocline was under destruction, the pH was less than summer and was mainly 8.25 at the water surface outside of the shelf and 8.3-8.35 in the shelf and gradually reduced with depth. In early spring, during the process of the formation of the new seasonal thermocline, low temperature and maximum local river inflow, pH at the water surface was mainly 8.25 and reduced to 8.2 at 30-m level. The results showed seasonal variations of pH in the southern Caspian Shelf and the coastal waters adjacent to Iran as a function of seasonal variations in water temperature, characteristics of thermocline, local rivers chemical characteristics and discharges, and production or destruction processes.

This research attempts to assess the history of tsunami occurrences and potential for tsunami generation at the southern coasts of Iran bordering the Indian Ocean by providing a list of historical tsunamis in this region and also, modeling of phases of tsunami generation and propagation. After the December 2004 mega-tsunami in the Indian Ocean, wide efforts were devoted to assess hazard of tsunami, and to develop tsunami warning and mitigation systems in the region. To assess the hazard of tsunami in any particular region, the compilation of historical records of tsunami is always the first primary task. Such a list may lead to useful information about the return period of tsunami events, and most vulnerable coastlines to the impact of possible tsunami. Regarding this fact, in the framework of this study, the first list of Makran historical tsunamis is provided. The Makran zone is located offshore Iran and Pakistan and any tsunami in this region would affect coastlines of Iran, Pakistan, Oman, and India. The last major tsunami in this region was produced following the occurrence of an 8.1 magnitude earthquake which took the lives of at least 4000 people all over the Makran coasts. Also, in this research, the potential for tsunami generation in the Makran subduction zone is quantitatively estimated through modeling of tsunami generation phase. In this regard, based on Mansinha and Smylie (1971) formulas a computer program has been developed to predict the ocean floor deformation due to the occurrence of underwater earthquakes in subduction zones. After the verification of model results, it has been employed to predict possible ocean floor deformation after the occurrence of underwater earthquake in the Makran subduction zone. Tsunami generation analysis shows that the risk of tsunami generation from Makran subduction zone can be classified into three main categories, as follows: (1) very little risk for tsunami generation in the case of occurrence of an earthquake having magnitude up to 7; (2) little to medium risk (Magnitude ranging 7 to 7.5); and (3) high risk (Magnitude greater than 7.5). In the next section of the paper, the tsunami propagation in the Makran zone was modeled. The results of tsunami propagation indicate that in the case of tsunami production in this region, the first tsunami waves will hit the nearest shoreline within 15 to 20 minutes. Finally, considering tsunami hazard assessment performed in this paper, the necessity for the development of a tsunami warning system in southern coasts of Iran was emphasized and its components and orderly sequences of tasks are proposed.

Marine environment of the Caspian Sea, due to extensive human exploitation and discharge of large magnitudes of urban, industrial and agricultural waste, is under extensive pressure. Nutrients such as phosphate and nitrate, and other human wastes are introduced into the Caspian Sea by river inflows and by direct waste dumping threatening marine life and eco system of the sea. High concentration of phytoplankton in marine environments occurs in response to introducing of nutrients by human activities and results in several harmful effects on the marine environment. Therefore, distribution and concentration of chlorophyll a as an indicator of the biomass of phytoplankton is very important in the study of water quality and ecological characteristics of marine environments. This paper presents distribution and seasonal variations of the concentration of chlorophyll a over the continental shelf of the Caspian Sea adjacent to Iran. The chlorophyll data were collected down to 200m depth in two areas in east (off Bipolar in Mazandaran) and west (eastern coast of Anzali in front of Sepidrood River) of the southern coast of the Caspian. The data were collected using a flourometer sensor of a CTD probe in autumn 2003, autumn 2004, and winter and spring 2005. The results showed that the chlorophyll a concentration in the study area ranged between 0.91-0.99 mg/m3. Above the thermo cline the chlorophyll concentration mainly varied between 0.93-0.96 mg/m3. Below the thermo cline the concentration of chlorophyll a was mainly 0.91 mg/m3 with small variation with depth and no significant seasonal variation. The observed chlorophyll a concentrations in the southern coastal areas of the Caspian Sea were high and indicated large inputs of nutrients into this area. The results show the necessity of certain measures for the decrease of nutrient inputs into the Caspian Sea in particular from urban sewage and agricultural waste.