نشریه آب و توسعه پایدار
سال دوم شماره 2 (پیاپی 5، پاییز و زمستان 1394)

Water resource Constraints on the one side, the industrial and urban infrastructures which cannot cope with the growing demand, and the need for adequate planning on the other hand, emphasizes the importance of using a comprehensive and systematic approach in the field of water resources management and infrastructure development more obvious and significant day by day. Also, exposure to large amounts of data and spatial data in such infrastructures, raises the use of new technologies for collecting, storing, processing, accessing, modeling, and finally the decision making process in the shortest time, with the highest accuracy and lowest costs. In this paper, as well as the investigation of GIS implementation in Shiraz Water and Wastewater Company, the spatial data in this company and all the information contained in the descriptive database that can be converted into spatial information to help enrich GIS database, were studied. Also, online communication between these databases and the GIS database was established through a Web service (Using SQL Server2008 database management system and Arc SDE interface). Finally, for decision and resource optimization management, the company's updated Spatial and description data through an Internet Map Server were provided to users in different fields.

This research aims at determining and evaluating the water productivity indexes in Astan-Ghods-Razavi Companies for different crops during 2007-2008 growth season. Required field data were collected during several field surveys. These data consisted of crop yields and crop consumptive water that is irrigated by distinct agriculture well. With regard to collected data, four water productivity indexes were calculated. To facilitate comparisons, the calculated water productivity indexes became dimensionless and then were scored. After that, common crops of different agriculture wells were compared together. The results show that Corn crop with score of 1.42 for Mashhad, Pistachio crop with score of 1.61 for Sarakhs, Wheat crop with score of 2.27 for Esfarayen, Pistachio and barley with score of 0.5 for Bardaskan, Corn crop with score of 2.27 for Torbat Heidarieh and Pistachio crop with score of 1.61 for Gonabad have best water productivity. Also, the best and worst crop water productivity among different sub-companies is Wheat crop in the Mashhad and Wheat crop in the Esfarayen and Alfalfa in the Gonabad together, respectively. Finally, it is found that Mashhad and Esfarayen are the best and worst sub-companies of water productivity.

Due to the being in the desert bar and ecosystem sensitivity to water , water management in the agricultural sector of the Iran is one of the priorities of managers and planners of this section. Therefore accurate modeling of the production function, for policies to increase efficiency and reduce the use of inputs, as well as forecasts for the timely supply with low cost, is of utmost importance. In this study, the production function in the agricultural sector of Iran has been modeled using underlying trend concept, creating a state - space model and Kalman filter algorithms. We used annual time series data for the period 1974-2012. The results indicate that underlying trend is smooth and Non-linear. According to likelihood ratio statistic, the most appropriate structure for hyper parameters is random static levels with No-slope trends (Local Level Model). Capital, labor and energy elasticity were less than unity, But water elasticity was larger than unity which is obtained in the first production area. This means that with a one percent increase in water inputs causes a decrease in production of more than one percent. Because, Iran is faced with limited water resources, cannot increase the consumption of water in this sector. Thus, recommended the replacement of new irrigation systems to compensate for water deficit and also in agricultural production by needs less water. Also, the development of basic technologies (changing the agricultural system) can reduce the use of inputs and compensate the lack of water in the agricultural sector.

Water is a valuable and irreplaceable element for the socio-economic development of countries. It is also the most important factor for the equilibrium of the ecosystem and environment. Todays, several factors cause water problems and related issues around the world. Governments and nations are always looking for the correct understanding of water issues and providing sustainable solutions to solve these problems. This attitude causes governments, institutions and water authorities to get together in international meetings. Hence, international festivals are held around the world in order to enhance solutions to water problems, make a global dialogue and take advantage of collective wisdom to resolve water related issues. In most of these events, some prizes are awarded to those who have made outstanding contributions in the field of water problems. The purpose of this paper is to review the most important international events in this regard and introduce effective criteria for achieving international water awards.

Human activities in the fields of agriculture, municipal and industry introduce significant amounts of nutrients and organic materials into the rivers and streams resulting in their contamination. Computer models such as Qual2kw are used extensively for water quality management of rivers and streams. The Qual2kw model is a one dimensional, non-uniform, steady water quality model, which has been used by the United State Environmental Protection Bureau and was developed based on the Qual2e model. A water quality model provides a feasible framework by simulating the important physical, chemical and biological processes. Qual2kw is able to simulate a number of components including temperature, pH, carbonaceous biochemical demand, sediment oxygen demand, dissolved oxygen, organic nitrogen, ammonia nitrogen, nitrite and nitrate nitrogen, organic phosphorus, inorganic phosphorus, total nitrogen, total phosphorus, phytoplankton and bottom algae. The main equation which the aforementioned model attempts to solve is the one-dimensional convection-diffusion equation which is applied for each constituent, except for variables related to river-bottom algae. Applications of Qual2kw are found in numerous cited literature. In this paper, based on the model manual, the equations used in the modelling process are described. Also a practical guide for users who want to use this model has been presented.

Sulfide production has been one of the most important problems in sewage collection systems that came to be known as an important factor of corrosion in concrete sewerage systems since early 1900. The emission of hydrogen sulfide gas in sewerage conduits creates problems including biological corrosion of concrete, release of repulsive odors in the city environment, as well as the potential danger that the toxic sulfide gas poses for the workers. Several factors such as high sulfate density, the organic material, temperature, waste water retention period, pH, Oxidation reduction potential (ORP), flow rate and surface area can increase the probable emission of sulfide. Due to the adverse effects of this chemical material, in recent years broader studies have been conducted on the control of sulfide production in sewage collection networks, including the injection of air, nitrate, H2O2, and iron salt. The purpose of these studies was to find suitable solutions for controlling the emission of hydrogen sulfide taking into account the construction conditions and economic profitability. This article is a review of all the research done on controlling the production of sulfate in sewage collection systems. It also reviews the advantages and disadvantages of the methods used in these studies which have examined the effectiveness of using formaldehyde, MgO2/CaO2, MFCs, nitrates, microbe-eliminators. The results of this study show that using the aforementioned chemical and biological materials for controlling the challenges of hydrogen sulfide production in sewerage, besides being economical and effective, are able to protect sewerage from corrosion and we can also arrive at a healthy and odorless environment.

The Part of precipitation that directly meets the water requirements of a plant, is termed the effective rainfall. Effective rainfall estimation methods consist of: direct measurement, empirical methods, and soil-water balance modeling. Due to the high costs of measurements and storing devices such as lysimeter, empirical and balance methods are most commonly used to estimate the effective rainfall. In this paper, as well as introducing the main methods of effective rainfall estimation, the benefits, drawbacks, and applications of each method are discussed. Based on the reported literature, the balance method, in spite of its need for exact data regarding the physical elements, after the direct measurement methods, has the most accuracy. The potential evapotranspiration ratio method is the most effective approach for basic projects. The Renfrew equation because it is very empirical, is therefore not a suitable method. The USDA method is also not appropriate for areas where the quantity of rainfall is more than the potential evapotranspiration rate. The highest effective rainfall amount is given by the USDA method and the lowest level is given by the Reliable method. In addition, the results of the empirical approaches, as well as the US Soil Conservation Service, US Department of Agriculture and Percentage method give similar results. In arid and semi-arid areas, the potential evapotranspiration to precipitation method and the soil conservation department of the United States provide the best results. In wet areas, the Reliable method is chosen as the most appropriate approach to planning because it provides more realistic values.

Due to the lack of fresh water resources, the use of saline water for the production of plants such as wheat and kochia is inevitable. To sustain production, the effect of saline water on the plants and soil in each region must be studied. Therefore in this paper, the effects of irrigation with saline water to produce plants such as wheat and kochia, as well as changes in the soil salinity profile (in terms of farmers and research fields), were evaluated in Golestan province based on the results of previous studies. Overall, the results indicated that the use of saline waters, which are unsuitable based on water quality criteria in the agriculture sector, have a significant effect on increasing production. Yield production was acceptable in saline lands in which the soil salinity was above the threshold of the plant (such as wheat, barley, canola, and kochia) salinity tolerance. In the short term, the salinity distribution of the soil profile at planting and the early growth stage of wheat was lower because of the sufficient rainfall during the autumn and winter periods. The main causes of salt accumulation and gradual increase of salinity in the soil profile are poor drainages and inadequate leaching mainly due to inadequate rainfall during the off season. If saline water was used for salt tolerance summer crop (such as kochia), the winter and autumn rainfall reduces the surface soil salinity and provides an important opportunity for emerging for the next year. Although rainfall is an unpredictable element, for sustainable production under a saline condition in some years leaching is necessary for reducing the salinity.

Evaporation is one of the main parameters for the optimum operation of reservoirs, design of irrigation systems and scientific management of water resources. Accurate estimation of the water evaporation level is crucial in any region especially in arid and semiarid regions. In this study, the feasibility of simulation of pan evaporation in Maraghe station using the multiple regression models were investigated. Meteorological data, including the maximum and minimum air temperatures, dew point temperature, the maximum and minimum relative humidities, the number of sunshine hours, the wind speed records during the 1992 to 2012 (using the daily time scale) of Maraghe synoptic station were used. Various models of multiple linear regression (MLR) were derived for simulating the evaporation in the mentioned station. The selected MLR model was tested for multi-collinearity of input repressors using the Ridge Regression. For this purpose, the Variance Inflation Factor (VIF), responsible for the multi-collinearity in regression analysis, was calculated for each of the input variables. The results showed that all of the obtained VIFs values were less than 10 and the multi-collinearity is not created. Furthermore, the ratio of eigenvalues of the correlation matrix, λmax\λmin, for the selected model was calculated as 6.2. The selected model consisted of the maximum relative humidity (RHmax), number of sunshine hours (n), and minimum air temperature (Tmin) as independent inputs, and the Pan evaporation as the dependent variable, f (RHmax, Tmin, n). Therefore, it can be concluded that there was no multi-collinearity in the selected MLR model. The RMSE and R2 values of the selected model (MLR) was calculated as 2.37 and 0.676 mm/day, respectively.

The three practical steps that are need to be taken by government agencies in order to increase irrigation efficiency include economic motivation for optimization of water use, modification of existing irrigation systems in the short term and modernization of traditional methods in the long-term plan. The present research aims at identifying farmer's knowledge regarding irrigation and water issues over two years (2008-2009) in the Golestan province. The study was a field survey and the data was collected through interviews with the farmers as well as completion of questionnaires. Results showed that source of water supply for approximately 76% of the farmers was from wells, approximately 18% from rivers, and the rest of them from springs, irrigation networks and small reservoirs. More than 89% of the convenience channels were earth channels, 8 % lining and 3 % pipes. Knowledge among farmers about irrigation scheduling was very limited. Nearly 95% of the farmers do not have any information about the water consumption in their field. Most farmers (93%) produced in a traditional way, transferred water by earth canals and irrigated without land leveling. Only 7% used pressurized irrigation systems. The results also showed that the main causes of water losses in the fields were related to earth channels (26%), topography (29%) and inadequate irrigation (20%). Unreasonable cost of water, the small size of farms, and private possession of water resources were key factors for improving irrigation efficiency.

Evaluation of any irrigation system consists of analyzing the measurable performance of the system in real conditions as well as during the normal operation of the farm. Irrigation evaluation is a management tool that allows the system manager to make the best use of what is available. Unfortunately, in most regions of Iran, after the implementation of irrigation systems their performance is not controlled or supervised. Also, during the operation of the system, the efficiency is not monitored nor analyzed either. Furthermore, the importance of irrigation system evaluation is not clarified to the users in our country. Despite the numerous research that has been conducted on the evaluation of center pivot irrigation system performance by domestic and foreign scholars, due to the complexity of existing evaluation methods, most farmers are not able to use them. Thus, in this paper, we have aimed to provide concise and simplified instructions for evaluating center pivot irrigation systems in order to help farmers in using them more readily. For evaluation of an irrigation system, the use of indexes such as water distribution uniformity, potential output and actual output for irrigation are recommended. Water distribution uniformity is an indicator of the water distribution problems in an irrigation system. The potential output of irrigation index describes the system performance under the current circumstances. Actual output of irrigation is an index that identifies the irrigation management, however it does not show the accuracy of the irrigation system design. According to the review conducted from academic resources, for a center pivot irrigation system, with a water distribution uniformity value of less than 76%, the irrigation potential and actual outputs value of less than 80% and 75%, respectively, are not suitable.