مجله تحقیقات منابع آب ایران
سال دهم شماره 1 (پیاپی 29، بهار و تابستان 1393)

Uncertainties and errors in water resources management decision making could result in the serious social and economical consequences.This can be caused by various factors such as price yield and iflow prediction that the latter usually has more complications, In this research it was attempted to present a water resources allocation algorithm under the uncertainty conditions using the concept of conditional value at risk (CVaR). In this regard' an optimization-simulation model considering water quality and quantity was developed which is able to calculate the optimal amount of water allocation in irrigation networks considering crops and their growing stages with minimal risk that resulting from uncertanties inflow prediction. In this study the information of Zayandeh¬rood irrigation networks during 1983-2008 were used for assessment of this presented procedure.The results showed that using CVaR as a probabilistic concepti in water allocation model can determine both the system risk in time horizon and the optimal water allocation considering the minimal loss and the risk caused by uncertainty and also determine the good probabilistic decision space for users to make realistic decisions.

Administrative allocation of water in Iran currently leads to more conflicts and severe water sectoral competition., Since the administrative water allocation is based on the low tariffs and not on market prices particularly in agricultural sector, the real value of water is not considered in the system of national account and monetary circular flow of economy. While water resources are the direct and indirect primary input of many commodities and services in the economy. One of the main strategies of coping with water scarcity is market-based allocation for making the highest value. The aim of this study is to analysis the welfare effect of water-based market allocation in the Iranian economy. According to backward and forward linkage effect of water sector on the economy, in this study the computable general equilibrium modeling has been used. In order to consider the real value of water, this study has been added raw water as the factor of production in the social accounting matrix. The results show that the creation of water market under water scarcity condition tended to respectively decreases and increases in the welfare of urban and rural households. Furthermore, the top deciles of rural household’s welfare have been increased in comparison to the lower deciles, which indicate the larger share of ownership of lands with water rights in the higher deciles.

Groundwater is an important source of fresh water supply in Iran. In the event of contamination, the restoration process for these resources is not always possible. One proper way to prevent contamination of aquifers is identifying vulnerable areas. The uncertain boundaries is affecting factor in aquifer modeling as a spatial phenomenon. Many theories have been proposed for uncertainty. In this study, Rough Set Theory and Geographic Information System (GIS) have been used in modeling of groundwater vulnerabilities uncertainty in DRASTIC model. Urmia plain which is the central plain near the Urmia Lake has been selected as the study area. Modeling with the use of Rough Set is performing in two high and low approximations. Accordingly the upper percent in the DRASTIC indicator for the high approximation was associated to the low to medium contamination potential and for the low approximation was associated to the very low contamination potential.

Sudden contaminant load in water resources either man made or in circumstantial process causes crisis. Appearance of MTBE contaminant load in Geshlagh Dam in Sanandaj city, entering the sudden contaminant load of oil determinatives into Zayandehrood River and Karkhe River are examples of such crisis that have occurred in Iran. The purpose of this study is evaluating and simulation of reservoir quality behavior in case of sudden contaminant load. This can help the managers and planners in selecting the applicable policies in the situation of quality crisis. In this paper, Karaj Dam reservoir simulation model has been created by the third version of two-dimensional mean transverse (CE-QUAL-W2) and a biological contaminant with coliform index has been considered as a sudden contaminant load. By considering the factors affecting the behavior of advection, dispersion, diffusion, and deterioration of coliform, five different scenarios have been created for 12 months of the studied year. These included coliform deterioration rate, the effect of reservoir water storage volume, contaminant load input location, the effect of water temperature, discharge into the reservoir, and the coliform sediment rate. Based on the defined scenarios, the rate of influences of each abovementioned factor on the behavior of pollutant has been investigated. The result shows that the input location of the contaminant load has a severe effect on the maximum output contaminant and crisis period. Therefore entering the contaminant load at the lower third of reservoir comparing to those of at the upper third of the reservoir has 15 times more output contaminant and the crisis period due to entering the contaminant load at the lower one third of the reservoir is two times of the crisis period due to entering the contaminant load at the upper one third of the reservoir.

Due to lack of appropriate data, estimation of water balance components for large areas is usually problematic. Recent development of global databases based on satellite estimates as well as rapid progress in hardware and software for modeling of complex processes governing the water balance at the land surface, caused that many efforts employ these new tools to reduce the limitations in this field. Gravity Recovery and Climate Experiment (GRACE) and Global Land Data Assimilation System (GLDAS) are two particular projects, which has recently been used by many scientists to estimate water balance in different regions of the world. Regarding the lack of attention to this free information in Iranian studies, this research aims at investigating the possibility of using these resources in estimating the water balance of Iran basins. Urmia lake watershed was selected as a study area and the water balance components were extracted from GRACE GLDAS data. Comparison of the estimated changes in total water balance of the basin by GRACE data and changes in the lake water volume based on observations showed a similar trend. Besides, estimation of annual variations in groundwater using GRACE and GLDAS showed suitability of GRACE data for study of the groundwater changes. Overall, the results of present study indicated that GRACE data can be used as an appropriate tool to perform a preliminary, rapid, and inexpensive assessment of water balance in watersheds of the country.

Demand management in water resources planning is a direct way to increase the net benefit generated by water known as the water use productivity. Considering the water scarcity in the recent years and the unbalance between water demand and water resources, demand management, incentive creation, improving public awareness, and establishing laws and regulations are required to decrease the water consumption, which leads to an improved water productivity. Utilizing economic instruments especially water pricing is one of the useful strategies in demand management. In this study, water pricing and incentive strategies including loan and partial grant to farmers were implemented and simulated in Zayandehrood river basin for a ten-year planning horizon (1997-2006). Also the effects of water pricing and incentive strategies on improving the irrigation efficiency, water productivity, and water consumption are investigated. To maximize the net benefit an optimization model was used with the objective function of maximizing the potential maximum net benefit. The results show that application of incentive strategies with decreasing water consumption increases the net benefit in the 10-year planning horizon to 24932 Million Rials which is 1.8 times of historical values. Based on the developed model and by combining of linear programming and budgeting methods the economic water value is estimated. The results show that improving the irrigation productivity lead to an increase in the economic water value from 1350 to 1780 Rials at the end of the planning period. The results show if water pricing and incentive strategies are used for improving irrigation efficiency, it can persuade the consumers for a decrease in water demand.

The perceptible water is the mass of water vapor (in grams) in a vertical column one square centimeter in cross-section that extends from Earth's surface to the upper reaches of the atmosphere. In order to estimate trends and long term changes of perceptible water over Iran, the NCEP/NCAR data during 1961- 2011 have been used. This database is available for 00:00, 06:00, 12:00 and 18:00 o’clock and by a resolution of 2.5 longitudes 2.5 latitude. The Grads and Matlab Software has been used for the calculation purposes. Also Surfer software is used to illustrate and drew the maps. The result of this research has shown that perceptible water over Iran is dramatically vary in space, especially over mountain ace area i.e. Zagros Mountain chain. The lowest spatial variation has occurred in the central region of Iran and over the Caspian Sea and the Persian Gulf coasts. The long term trends showed that for all times of the day the perceptible water has experience decreasing trends over 70 percent of the country extent with significance level of 95%. In southeast of the country, this decreasing trend also exists but is non-significant in 95% confidence level.

This research attempts to develop and improve the simulation of incompressible flow and wave propagation due to dam break. Using Smoothed Particle Hydrodynamics (SPH), a consistent predictive-corrective method is introduced to simulate free-surface flows in dam break. For this purpose, two new SPH schemes are presented for spatial discretization of first and second derivatives in viscosity and Laplacian pressure terms at Navier-Stokes equations. These proposed schemes overcome the weaknesses of existing schemes, and has the properties of consistency and stability. Next, using Eulerian approach and Volume of Fluid (VOF) method in the open-source software of OpenFoam, two-phase unsteady flows due to dam break are simulated in two dimensions. In order to assess the accuracy and performance of the proposed methods, the obtained results are compared with each other and with reliable experimental and numerical solutions in the literature. It was shown that two presented approaches are able to handle the violating free surface flow in dam break problems with high accuracy. Particularly, the proposed SPH method leads to consistent, stable and convergent solutions especially for pressure distribution.

The decision to avoid a gradual salinization and swamping requires understanding the origin and the extent of salinity as well as quantity and up-to-date information of the area. Processing and interpretation of imagery satellite and regional analysis of statistical data such as electrical conductivity and groundwater table level variation can be used in recognition the salinity and swamp lands. In this study, with generating the historic and existing land use map and quantitative analysis of salinity index parameters, the effectiveness of the remote sensing using satellite landsat TM and ETM+ sensors from the summer of 1992 and 2002 was illustrated. This research also showed the quantitative variation in salinity and swamp land surface of BEHSHAHR plain in the period of 1986-2002. The result showed an increase in the saline land area and lands with drawdown in the groundwater table level for the expressed period. The results were consistent with the analysis based on the results of the interpretation of satellite images such as increase in classes of salty land use, rainfed–salty land use, decrease in irrigated agricultural and orchards, and increase in the rainfed farming lands.

Digital Elevation Models (DEMs), due to their simple structure and high performance, are favorably being used for rainfall runoff modeling in modern hydrology. There are different methods for DEM creation via topographical data interpolation. To create DEM in this research, 6 different methods of IDW, Kriging, and Co-Kriging, embedded in ARCGIS, were used. The TOPMODEL which is a semi distributed topographic-based rainfall runoff model were investigated to search about the effects of the DEM creation method on the results of these types of models. The results showed that the TOPO index, as the most important basic parameter for the TOPMODEL, is highly sensitive to the DEM creation method. The consequences of this sensitivity, was illustrated by different extent and distribution of the saturated zones across the watershed. Accordingly, the amount of surface runoff was highly affected by the DEM creation method, while this effect on the total amount of river discharge was negligible and the Nash- Sutcliff index variation could be ignored.