نشریه آب و توسعه پایدار
سال چهارم شماره 2 (پیاپی 9، پاییز و زمستان 1396)

Today in the light of the competitive markets, diversity of products, political and economic evolutions, climate changes, depletion and pollution of a number of natural resources etc., the science of economy has extended its limits beyond the linear economy (production – distribution – consumption) and is moving towards a circular economy (production – consumption – recycle). In addition to the main objective, the reduction and recycling, or reusing of the waste from production processes, is the main ideal of circular economy. The topic of circular economy in the water and wastewater industry can be considered from the aspect of its specific features (simultaneous consumption of water and the generation of wastewater), negative impacts of wastewater on the environment, water scarcity caused by growing population, the intense competition among water consumers (agriculture, industry, and domestic), reduction of the per-capita water resources, consecutive droughts, and the reuse of wastewater in the course of sustainable development. While explaining the fundamentals of a circular economy, sustainable development, and reuse of wastewater, this paper tries to analyze and review the interaction of these components and the requirements and opportunities of the circular economy in the reuse of wastewater in the course of sustainable development. Also, in this study, using the economic value of water in different economic sectors of the country and the wastewater allocated to these sectors, the share of wastewater in creating the economic value added to the country in 1394 is calculated. The results show that the circular economy of wastewater will create IRR 2251 billion (0.02% of the total national value added) and that the correct management and planning for efficient reuse of wastewater can play an important role in the national economic value, water resources management, and sustainable development.

Nowadays, cost and quality are considered two basic factors which contribute to a competitive advantage in the industry. Hence, in recent years, there has been much interest in examining the relationship between these two competitive advantages, especially in leading industries such as public utilities. Such that, the increase in the competitiveness of these companies has increased the importance of focusing on reducing production costs as well as increasing the quality of services. On the other hand, manufacturers always try to reduce production costs and also maintain the quality of products and services at the level of consumer expectations. Therefore, in this research in the water and wastewater industry, firstly, the most important factors for creating cost of quality are identified and ranked by using the Fuzzy AHP algorithm and the Fuzzy TOPSIS. Also, appropriate solutions have been proposed along with quality cost stimulus factors. The results show that the most costly variable in the quality of the water and wastewater industry is the evaluation cost (36.5%). Other quality costs are, External defeat (28.9%), internal defeat (22.3%), and prevention (12.2%).

Wetlands are valuable ecosystems that have a variety of functions to protect biodiversity, natural values, economic and social values. The importance of wetlands, especially in arid and semi-arid regions such as Iran, is higher. Wetlands can reduce the effects of climate change in different ways. Hence, the degradation of wetlands will intensify the climate change impacts. At the moment, the Anzali international wetland is under the impact of environmental stresses and pollutants such as the entry of the industrial, agricultural, and urban effluents, the presence of non-native species, changes in the purpose of usage, and eutrophication. Therefore, the need to study the spatial and temporal variations of pollutants using qualitative indicators is one of the most important factors in water quality studies. In this study, due to the importance of the Anzali wetland and its environmental impact on sustainable development, an ecosystem quality survey was conducted using the data from seasonal sampling which took place in the year 1393 at 10 stations using NSFWQIa, NSFWQIm, and OWQI qualitative indices. Based on the results of the various indices, most stations are categorized in having middle to very bad levels. During the summer season, the most polluted stations according to the NSFWQIm, NSFWQIa, and OWQI indices were Nokhale, East of wetlands, and Pirbazar, respectively. The variance analysis showed a significant difference (p

Considering the environmental regulations on exhausting sewage from treatment plants and its application in agriculture, this research investigates the use of activated sewage efficiency in the generative sewage treatment of Kermanshah city and its application on agriculture irrigation through 2007 to 2008 using the cross-sectional method. During the course of this study, sampling was carried out from the inlet and outlet of the sewage treatment plant on a daily and weekly basis. Treatment plant efficiency was calculated through the measurements of TSS, COD, BOD5, MLVSS, SVI, and MLSS from the entrance sewage and exhausting effluent based on the latest standard methods presented in 1999. Also, indices relevant to the agricultural usability were calculated and compared with the national standards. Results showed that physical, chemical, and biological traits of sewage pollution intensity were at an average level and the treatment plant pollution efficiency was relatively acceptable. The average concentration of dissolved oxygen (mg/l), SVI, MLSS, and MLVSS in the aerated pool was compared with the environment protection standards of Iran showed that the exhausting effluent can be used in drip irrigation. Despite the appropriate control of the active-sludge process in all parts of a sewage treatment plant, results showed a lack of adequate management on its sustainable consumption such as its application in the production of agricultural fertilizers.

In this research to investigate the flood risk over the Chandir spillway, located in the North Khorasan province, the acceptable distribution of risk for the spillway components and its consequences on the hydraulic performance were studied. For this purpose, the spillway was designed for discharges with a return period of 100 and 1000 years. The 3D flow field for the designed structure was investigated in the event of flooding with a return period of 100 and 1000 years using the FLOW3D software. The results show that in the event of a flood with a 1000-year return period, whilst the structure has been designed based on a discharge with a 100-year return period, flow separation and an increase in the local shear stress occurs in the stilling basin. Moreover, the risk assessment results show that the stilling basin length plays an important role in flow energy dissipation however, increasing the stilling basin length more than 20 meters would not decrease the dissipation rate. Also, the length of the stilling basin influences the amount of the secondary depth, and the reducing of the basin length to less than 15 meters will prevent the formation of a hydraulic jump even for a discharge with a return period of 100 years. Finally, the risk assessment shows that by accepting the risk amount of 13.56 %, it is possible to reduce the length of the stilling basin to 20 meters.

Water leakage in the water distribution networks results in losses of supply, pressure, and capital investment. Therefore, efforts to reduce the leakage in the water distribution networks have great importance. A common way to reduce pressure is the installation of flow or pressure reducing valves (PRV) and the optimal regulation of these valves in water networks. This study aims at investigating the optimum management of pressure in order to minimize the leakage in water distribution networks. For this purpose, the optimal placement and setting for pressure relief valves, with minimum allowable pressure in the nodes, is considered as the main constraint of the problem. In the present research, to solve these problems, an optimization model—a simulation based on an emerging algorithm called Cultural Algorithm (CA)—was used. In this model, the CA optimization in MATLAB environment was integrated with the hydraulic simulation of the EPANET model. The results revealed that, considering all the limitations of the problem, employing this method to determine the position of the pressure reducing valves and regulating them lowered the mean leakage rate of the network by 10% in three periods of maximum, average, and minimum water demand.

Presently, floodwater spreading schemes are used as aquifer management projects in the country. In these projects, spreading a large volume of floods containing salts and suspended loads over the spreading network, may lead to differences in soil salinity and alkalinity. Therefore, it is necessary to study the amount and the trend of these differences over time in order to produce a suitable method to increase the utility of such designs. In this research, the results of 40 studies on the effects of spreading floodwater on the soil properties were evaluated. In general, studies show the improvement of the quality of some of the soil physical and chemical properties due to the floodwater spreading. These effects include: more balanced soil texture and soil moisture conditions, improved soil physical and chemical conditions, increase in some of the soil elements and consequently an increase in soil fertility compared to pre-construction floodwater spreading system, reduced infiltration, and providing suitable conditions for the growth of pasture plants and planted seedlings and consequently changing the ecological landscape of these areas.

This paper contains a comprehensive historic review of attempts for innovation and development of Subsurface Irrigation Systems from the early stage in different countries and regions. Firstly, the differences between two irrigation systems namely: "Underground Irrigation" and "Subsurface Irrigation" has been clarified and then the technical problems within innovations from the start of written history research on subsurface irrigation has been discussed. Describing all activities performed by the subsurface irrigation pipes, this study attempts to introduce the most important technical barriers which prevent the distribution of subsurface irrigation systems including methods available in the market such as subsurface drip irrigation, Porous irrigation tubing, and KISSS. Due to the limitations to mention all the technical issues related to different methods of subsurface irrigation, and to better understand the ability of each method, "Researcher's Evaluation" is mentioned at the end of each part. The last part of this paper is attributed to the development process of a new subsurface irrigation system "Subsurface Irrigation with Clay Pipes".

The two factors of the trend of climate change and urban development pose a challenge to urban drainage infrastructures due to the adverse impacts on precipitation extremes and urban environment. Nowadays, Sustainable Urban Drainage Systems (SUDS) have become quite popular as a result of their positive effects on the water quality, quantity, amenity, and recreational affairs in urban landscapes. Today, the majority of the world agrees that a sustainable drainage approach has an influence in reducing global climate change and adapting to this phenomenon (which has already started). The current paper reviews recent progress in the development of sustainable drainage, based on interdisciplinary studies. First, the reasons behind moving towards a sustainable urban drainage system are mentioned and then, existing models and decision-aid tools to assess different types of SUDS are compared and discussed. This paper also explains some limitations and challenges related to applying SUDS in practice and finally, the results and conclusions are presented.

The processes and components of hydrological cycle are very complicated in nature, with significant spatial and temporal variation. This is due to high non-linear and complex relations between hydrological components, economical limitations for accurate measurements, and requiring a variety of data and information. The main solution for understanding and predicting hydrological processes at watersheds scale is using/developing simulation models based on desired goals. However, due to the lack of attentions to the concepts and practical knowledge, development of hydrological models has attracted less attention. By neglecting the modelling process in hydrological modelling, and starting this process directly by choosing a procedural model and its calibration would provide unreliable results. Therefore, it is essential to have a comprehensive and accurate inspection of the modelling process and its application as a useful tool for understanding and analyzing hydrological systems. This paper aims at providing concepts of hydrological modelling and introducing five-steps modelling process for watersheds, and finally presenting information about the various types of hydrological models.

The purpose of this research is the introduction of methods and tools for determination of aquifer stratigraphy and their application. In alluvial aquifers which have extreme changes in sediments, stratigraphy modeling is not suitable, and it is better to use three-dimensional lithology models found in the Rockworks software or T-Progs tools in the GMS software. In this study, using the three-dimensional modeling techniques in the Rockworks software, the three-dimensional lithology model of the Bojnord aquifer lithology of the Bojnourd aquifer, located in the North Khorasan province, with information including logs and geophysical studies has been obtained. Here, the alluvial aquifer consists of three soil textures: coarse, medium, and fine grain which the very fine texture (very fine grain) is considered as the aquifer floor texture in order to solve the lithology modeling problem. Results show that the existence of lens and heterogeneity of sediment in the aquifer influence the accuracy of the estimated hydrodynamic coefficients. Therefore, using three-dimensional lithology modeling techniques, especially in alluvial aquifers, causes changes in the hydraulic conductivities of fine to very coarse-grained sediments. Additionally, the use of three-dimensional alluvial modeling techniques for groundwater flow modeling, especially in aquifers with severe heterogeneity, leads to the identification of an aquifer with an adequate accuracy.

In recent years that we are faced with water shortage, the entrance of surface pollutants to the groundwater resources has become a serious problem in reducing the quality of groundwater resources. Therefore, identifying vulnerable areas and directing development programs in the areas which have not been vulnerable to pollution is the best way to provide sustainable development programs. In this study, aquifer vulnerability have been assessed using DRASTIC and SINTACS models at the Jarmeh plain, khozestan province. The principle of the DRASTIC model is based on hydrological and hydrogeological pollution transmission conditioning factors. Entering the parameters for both DRASTIC and SINTACS is the same, the main difference between them is that weighing and rating in the SINTACS method is more flexible. Groundwater vulnerability maps have been provided using overlaying of water depth, net recharge, aquifer media, soil media, topography, impact of vadose zone, hydraulic conductivity, the results of the mdels and were validated using nitrate concentration map. Correlation between nitrate and groundwater vulnerability maps provided by DRASTIC and SINTACS was 0.36% and 0.48%, respectively. Sensitivity analysis was investigated to determine the most effective factors using map removal and single parameter methods. The results of both methods show that the unsaturated zone is the most important factor on groundwater vulnerability in the study area.

The pressure on ecosystem and the reduction of welfare and livelihood in human communities are one of the most important effects of drought which, if the severity and duration of this event increases, could become one of the most catastrophic natural disasters. Therefore, many countries have different climate-based policies in facing water stress issue, such as severe and prolonged droughts. However in almost all of them, groundwater has been considered as a strategic resource because of its reliability in water stress situations. Strategic groundwater resource refers to the volume of fresh groundwater that should be stored in an aquifer for various activities, especially for drinking water, and also to be gradually used for human needs in some serious long-term droughts. Strategic groundwater reserve is the most important support of water supply management in water stress conditions of "severe and prolonged droughts" particularly in arid and semi-arid areas. Unfortunately for many years, the concept of balancing water resources and developing sustainability has received little attention in Iran, consequently this unique water resource is continuously declining. This study sought the necessity of developing the concept of Probable Maximum Drought (PMD) as the basis for determining the maximum withdrawal of groundwater, as the most important factor for increasing resilient development in water stress conditions by preserving strategic groundwater reserves. The lack of attention to maintaining strategic resources could bring irreparable damage and cause changes in society. Finally, this study introduces suggestions for drought risk management based on the aforementioned concept hence, it is important to develop a comprehensive program for drought risk management in the event of severe and long-term droughts for each study area.

Appropriate management of irrigation networks in the country requires an active participation of farmers in WUAs where different factors affect the participation level in this regards. The aim of this correlational-descriptive study is to investigate the components that influence the farmers’ participation in irrigation network management of the Sahand Dam. The research tool was a questionnaire which its validity was confirmed by experts and by conducting a pilot study, and calculation of Cronbach's alpha higher than 7.0 for the composite indicators. The statistical population consists of all members of the three WUAs in the Sahand Dam Basin (N=34), which based on Krejcie and Morgan sampling table, 30 candidates were selected using a simple random sampling method. Data was collected by personal interviews in the villages and analyzed through the SPSS20 software. The results show that 73.3 percent of members had a medium and lower level of participation and their participation had a significant negative correlation with their age, family size, and years of agricultural experience. However, there was a significant positive correlation with their educational degree, social participation, social trust, social cohesion, usage of related information, usage of extension communication, and their knowledge of WUAs. Regression analysis show that the three variables of social cohesion, social trust, and age were responsible for 76.2 percent of participation variance. According to the results, with an increase in social capital among WUA members, the level of their participation in the management of water resources will be increased.

In recent years, ecotourism and tourism with a focus on water resources has attracted more attention. In many mountain valleys of Iran during the last fifty years, the use of natural resources, especially water, has continuously increased. A steady increase in the consumption and subsequent pressure on natural resources in the context of these areas has created serious challenges. The purpose of this study is to identify the role of water ecotourism in tourism development in mountainous areas using a descriptive - analysis approach. The weaknesses, strengths, opportunities, and threats to water resources in ecotourism development were extracted through closed interviews with 20 aboriginal candidates and 30 local authorities, and were made available in the form of a questionnaire to tourists. SWOT analysis shows that among all internal factors affecting the development of ecotourism in the area of water resources, 11 factors as strengths and 8 factors as weaknesses were identified and evaluated. The analysis shows that among all external factors affecting the development of ecotourism in the area of water resources, 10 factors as external opportunities and 9 factors as external threats facing these regions were identified. Finally, using the SWOT technique it was shown that the ecotourism in the area of water resources are very robust in the considered areas (3.33 and 3.34 points in terms of internal and external factors, respectively). In the considered area, there is a good potential for the agricultural crop and livestock packaging industry, rural small industries, and tourism activities. Relying on participatory management, development, and implementation of appropriate strategies, especially competitive, we are able to use the potential of the region to create jobs and income in order to reduce the pressure on natural resources, especially water, in non-agricultural sectors. The analysis of the data indicates that water ecotourism development cause the conservation of the environment so that it can provide the most use at the lowest cost.

One of the existing problems in water and wastewater companies is the management of pressure in the water distribution networks. Due to the direct relationship between the network pressure and the rate of users’ consumptions, modeling the spatial distribution of pressure in a hydraulic software is possible. However, because of the Spatial Reference of the water network database, GIS is the preferred approach. Also, all the hydraulic behaviors and its changes can be modeled with a high location accuracy with this software. In this research, database reference modeling for a water distribution network has been carried out, as well as implementing its physical model in the PostgreSQL and PostGIS open source spatial database network, where the cost of its production, development, and support is less than a similar commercial software. Considering that topographical factors, pressure, and consumers demand have the greatest impact on the optimal distribution of water at the network, solutions such as determining the correct installation location for the suggested pressure reducing valves instead of the existing ones in order to optimize the pressure in high pressure areas have been suggested.