Sharif Digital Repository

This paper describes the results of a study of potential environmental impacts of methanol releases into rivers. A number of hypothetical scenarios are defined, and dispersion of methanol in the selected rivers is investigated using a riverine dispersion-biodegradation model. The downstream variability of river flow and hydraulic geometry due to merging tributaries are included in the model. The model results are presented, and comparison is made with proposed allowable concentrations. An interesting finding is that the river variation has considerable effect on concentration distribution of methanol in the most critical scenario. A sensitivity analysis is made on the key modeling parameters... 

In this study, a coupling of a hydrologic and hydraulic model was utilized to assess the impacts of river geometry data resolution on the flood inundation characteristics in a data-scarce environment. Hydrological modeling incorporates soil conservation service curve-number (SCS-CN) and the geomorphologic based instantaneous unit hydrograph model (GIUH) to compute the direct runoff hydrograph in Kashkan river basin located in western Iran. 1D HEC-Geo-RAS model was used and performed to simulate inundation extent of 100-yr floods (~1800 m3/s) along 40 km reach of Kashkan river with a ground survey of river cross-section (2000 cross-sections, each including 500 data-points). The effect of... 

Recently, remote sensing considered as important tool in studies of water quality issues. The Aras River flows across a transboundary basin in northern Iran. In this study, the aim is to model the water quality parameters (WQPs) using remote sensing and an artificial neural network (ANN), which is a new method proposed to find WQPs based on multivariate regression approaches. The relationship between WQPs and digital data from the Sentinel-2 satellite was determined to estimate and map the WQPs in this river. Using the field data and digital image data, the obtained results show that multivariate regression approaches and high-resolution remote sensing could monitor and predict the... 

Various urban, industrial, and agricultural pollutions discharge more than river self-purification potential damages river ecosystem and increases water treatment costs. As different decision-makers and stakeholders are involved in the water quality management in river systems, a new bankruptcy form of the game theory is used to resolve the existing conflict of interests related to waste load allocation in downstream river. The river restoration potential can allocate to the conflicting parties with respect to their claims, by using bankruptcy solution methods. In this research, dischargeable pollution loads to Karun River are determined by pollution sources in various scenarios using... 

Deployment of renewable energies for the electricity generation is on the rise around the world, among which is the run-of-the-river (ROR) power plant whose output power is variable throughout the year depending on the water flow of the respective river. The inherent uncertainty associated with renewable energy resources calls for new stochastic modeling approaches to measure the impacts of using these energies on the power system performance. This paper develops an analytical reliability model for ROR power plants. The model is based on the state-space analysis and is devised with the intention of being used in adequacy studies of power systems. Failure of related components and the... 

This Regular evaluation and analysis of river quality helps accurate management to reach acceptable quality. In this study, water quality indices (WQI) method applied to evaluate quality of Jajrood River which is one of the main sources of Tehran drinking water. It helps to subsidize management actions in Jajrood watershed. Sampling carried out for 9 years during 2001-2010 in 10 stations along the river in wet and dry stations to identify water quality and the main source of pollution. Results show water quality in all stations classifies as medium according to National Sanitation Foundation (NSF) and water quality index in wet season is better than the corresponding value in dry seasons.... 

The Jajrood River watershed is on of the main drinking water resurces of Tehran, the capital city of Iran. In addition it provides many recreational usages. However, a variety of microbial pollutions is commonly perecived in the Jajrood River, among them a high concentration of coliform group bacteria that has caused strong concerns. In this article, different aspects of microbial pollution as well as the main microbial pollution sources in the region are discussed. Coliform group bacterial die-off rates have been evaluated as the key parameters that govern bacterial fate in the watershed and were estimated using both laboratory and field data investigations. The high values of the bacterial... 

Water quality is one of the most important factors contributing to a healthy life. From the water quality management point of view, TDS (total dissolved solids) is the most important factor and many water developing plans have been implemented in recognition of this factor. However, these plans have not been perfect and very successful in overcoming the poor water quality problem, so there are a good volume of related studies in the literature. We study TDS and the water flow of the Karoun river in southwest Iran. We collected the necessary time series data from the Harmaleh station located in the river. We present two Univariate Seasonal Autoregressive Integrated Movement Average (ARIMA)... 

Various urban, industrial, and agricultural pollutions discharge more than river self-purification potential damages river ecosystem and increases water treatment costs. As different decision-makers and stakeholders are involved in the water quality management in river systems, a new bankruptcy form of the game theory is used to resolve the existing conflict of interests related to waste load allocation in downstream river. The river restoration potential can allocate to the conflicting parties with respect to their claims, by using bankruptcy solution methods. In this research, dischargeable pollution loads to Karun River are determined by pollution sources in various scenarios using... 

Urmia Lake River Basin (ULRB) is one of the most important habitats in the world and one of the major agricultural regions in Iran. On average, the ratio of irrigation to evapotranspiration in this basin is more than 73%. Investigating the irrigation water requirement pattern changes and the spatial distribution of evapotranspiration during the basin development period on a regional scale play important roles in understanding the basin situation. In this study, the actual evapotranspiration has been estimated by SEBAL model. By estimating the precipitation distribution in the basin, the agricultural irrigation water requirement pattern has been calculated using the land use map in 1995, 2010... 

Development of visual detection methods regarding water pollutants can effectively facilitate water resource monitoring programs. A wide color-varying ratiometric approach has been developed for sensitive determination of sulfide by mixing orange emissive glutathione stabilized gold nanoclusters (AuNCs) and blue emissive urea stabilized carbon dots (CDs) in an appropriate ratio. Under a single excitation wavelength of 365 nm, the ratiometric fluorescence (RF) probe exhibited two distinct emission bands at 452 and 607 nm corresponding to CDs and AuNCs, respectively. Owing to the high affinity of sulfide ions to AuNCs in alkaline medium, the fluorescence (FL) of AuNCs was turned-off while the... 

Rainfall characteristics, which include spatial variability, exert a major influence on runoff properties. Many techniques have been proposed for determining the spatial distribution of daily rainfall. One of these techniques is spatial modeling, based on rainfall data measured by rain-gauge networks. In this study, application of different interpolation methods in the GIS environment, for estimating the spatial distribution of daily rainfall in the southwest of Iran with low rain-gauge density, have been compared on a regional scale. The cross validation technique was selected as an accuracy index and statistical parameters, such as MAE (Mean Absolute Error) and MBE (Mean Bias Error), were... 

In this paper, principal component analysis (PCA) and hierarchical cluster analysis (CA) methods have been used to investigate the water quality of Jajrood River (Iran) and to assess and discriminate the relative magnitude of anthropogenic and "natural" influences on the quality of river water. T, EC, pH, TDS, NH4, NO3, NO2, Turb., T.Hard., Ca, Mg, Na, K, Cl, SO4, SiO2 as physicochemical and TC, FC as biochemical variables have been analyzed in the water samples collected every month over a three-year period from 18 sampling stations along a 50 km section of Jajrood River that is under the influence of anthropogenic and natural changes. Exploratory analysis of experimental data has been... 

Observatory-scale data collection efforts allow unprecedented opportunities for integrative, multidisciplinary investigations in large, complex watersheds, which can affect management decisions and policy. Through the National Science Foundation-funded REACH (REsilience under Accelerated CHange) project, in collaboration with the Intensively Managed Landscapes-Critical Zone Observatory, we have collected a series of multidisciplinary data sets throughout the Minnesota River Basin in south-central Minnesota, USA, a 43,400-km2 tributary to the Upper Mississippi River. Postglacial incision within the Minnesota River valley created an erosional landscape highly responsive to hydrologic change,... 

Water-quality modeling and prediction is a complicated task because of inherent randomness and uncertainties associated with various processes and variables throughout the stream environment and the lack of appropriate data. Hence, the results of mathematical models are always approximate, lying within an uncertainty. This paper describes and demonstrates the application of the U.S. Environmental Protection Agency's water-quality model, QUAL2E-UNCAS, to the Zayandeh-Rood River in Iran. First-order reliability analysis is used to examine the variability of predicted water-quality parameters of total dissolved solids, dissolved oxygen, and biochemical oxygen demand. This analysis also... 

Coupling the adjacent zones for seepage analysis in porous media needs compatibility and equilibrium equations (equality of potential on coinciding nodes and conservation of flowing mass between zones, respectively). When stretched coordinate transformation is applied to the anisotropic zones, the Dirichlet boundary conditions remain unchanged, but the Neumann boundary condition should also be transformed. Similarly in a zoned problem, for the interface between zones, compatibility equations remain unchanged during the transformation while the equilibrium equations should be transformed. In this paper, transformed Neumann boundary conditions and equilibrium equations for the interface of... 

In this study Active Learning Method (ALM) as a novel fuzzy modeling approach is compared with optimized Support Vector Machine (SVM) using simple Genetic Algorithm (GA), as a well known datadriven model for long term simulation of daily streamflow in Karoon River. The daily discharge data from 1991 to 1996 and from 1996 to 1999 were utilized for training and testing of the models, respectively. Values of the Nash-Sutcliffe, Bias, R 2, MPAE and PTVE of ALM model with 16 fuzzy rules were 0.81, 5.5 m 3 s -1, 0.81, 12.9%, and 1.9%, respectively. Following the same order of parameters, these criteria for optimized SVM model were 0.8, -10.7 m 3 s -1, 0.81, 7.3%, and -3.6%, respectively. The... 

Elevated levels of nitrate (NO3) in groundwater systems pose a serious risk to human populations and natural ecosystems. As part of an effort to remediate NO3 contamination in irrigated stream-aquifer systems, this study elucidates agricultural and environmental parameters and processes that govern NO3 fate and transport at the regional (500 km2), local (50 km2), and field scales (<1 km2). Specifically, the revised Morris sensitivity analysis method was applied to a finite-difference nitrogen cycling and reactive transport model of a regional-scale study site in the lower Arkansas River valley in southeastern Colorado. The method was used to rank the influence of anthropogenic activities and...