technical paper
Irrigation network management
Arezou Mokhtari hesari; Alireza Nemati
Abstract
Extended AbstractIntroductionThe majority of agricultural areas worldwide are managed using traditional surface irrigation methods. However, these methods face significant challenges, including inefficient water use and suboptimal productivity. Given their widespread use and low efficiency, improving ...
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Extended AbstractIntroductionThe majority of agricultural areas worldwide are managed using traditional surface irrigation methods. However, these methods face significant challenges, including inefficient water use and suboptimal productivity. Given their widespread use and low efficiency, improving surface irrigation systems has become essential. In recent decades, numerous initiatives have aimed to enhance the efficiency of irrigation systems and management practices. One such advancement is the development of low-pressure irrigation systems. Studies based on behavioral theories examining farmers’ adoption of irrigation technologies have identified several influential factors. Accordingly, this study aims to explain the role of technology ease of use and farmers’ self-efficacy in influencing their behavior toward adopting and using modern low-pressure irrigation systems. Materials and MethodsThe method of this research follows a quantitative paradigm. In terms of purpose, it is applied research, and in terms of data collection, it is descriptive research conducted through a survey. In total, 112,010 farmers in East Azerbaijan Province formed the study population, and a sample of 393 was selected using the Cochran formula through multi-stage sampling. The main data collection tool was a researcher-designed questionnaire consisting of three parts: the first part relates to the individual characteristics of the farmers, the second part concerns the characteristics of the exploitation system, and the third part includes items related to the main variables. The face and content validity of the questionnaire were confirmed by professors and subject matter experts. The reliability of the research instrument was determined using Cronbach’s alpha, and construct validity was assessed through convergent validity using confirmatory factor analysis. SPSS 20 and AMOS 21 software were used for data analysis.Results The measurement and structural model analyses indicated that model fit was acceptable across multiple indices and that the hypothesized relationships among the variables were logically consistent. Hypothesis testing revealed that all proposed relationships were statistically significant. Specifically, there was a positive and significant relationship between the perceived ease of use of the low-pressure irrigation system and farmers’ willingness to adopt it. Additionally, farmers’ self-efficacy was found to be significantly associated with their willingness to use the technology. Overall, structural equation modeling showed that ease of use and self-efficacy together explained 60% of the variance in farmers’ willingness to adopt low-pressure irrigation systems, with ease of use emerging as the stronger predictor. ConclusionsThis study investigated the factors influencing farmers’ adoption of low-pressure irrigation systems. Specifically, it examined the effects of perceived ease of use of the technology and farmers’ self-efficacy on their willingness to adopt such systems. The findings confirmed that both factors significantly influence adoption, with ease of use playing a particularly strong role. When the equipment, connections, and maintenance of the irrigation system are simple to operate and learn, farmers are more likely to adopt low-pressure irrigation. Additionally, farmers’ confidence in their ability to implement water conservation strategies enhances their conservation behavior. In other words, effective water conservation depends on farmers’ understanding and belief in their own capabilities.
Original Article
Hydraulic
Saeed Akbari Zade; Ehsan Fadaei-Kermani; Mahnaz Ghaeini-Hessaroeyeh
Abstract
Extended AbstractIntroductionUrban sewage collection systems in areas with rugged topography present significant hydraulicchallenges. Steep slopes and substantial elevation differences generate high kinetic energy in the flow.Without proper control, this excess energy leads to adverse consequences, including ...
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Extended AbstractIntroductionUrban sewage collection systems in areas with rugged topography present significant hydraulicchallenges. Steep slopes and substantial elevation differences generate high kinetic energy in the flow.Without proper control, this excess energy leads to adverse consequences, including erosion and degradationof the channel bed and walls. Further issues may involve structural damage and vibrations induced by highenergyflow, the entrainment of large volumes of air due to free-falling sewage, and the potential for waterhammer in closed systems. To address these challenges, vortex drop structures have been introduced as anefficient engineering solution. These structures establish a controlled vortex flow pattern within a verticalshaft, thereby dissipating the incoming flow's excess energy in an effective and manageable manner.MethodologyIn the present study, a physical model of a vortex drop structure was constructed to investigate itshydraulic performance, including the spiral inlet and the shaft. Furthermore, since the structure's performancein flow energy dissipation is significantly influenced by the upstream and downstream hydraulic conditionsand geometry, the rate of flow energy dissipation by the structure was measured.A 1:10 scale physical model of the East Tehran Sewer Vortex Drop Structure was constructed in theHydraulic Structures Laboratory of Shahid Bahonar University of Kerman, Iran. The model comprises arectangular approach channel, a tangential vortex inlet, a drop shaft, an energy dissipator, and a rectangularoutlet conduit. In this study, a spiral inlet with different outlet diameters was employed. The inlet channel,with a rectangular cross-section, conveys the flow to the tangential inlet structure. This channel measures0.18 m in width (B) and 0.21 m in height. Downstream of the vortex drop structure, the flow exits via arectangular outlet conduit measuring 0.18 m in width and 0.24 m in height.The model begins with an initial reservoir; upon filling, water enters the structure through the inletchannel. The wall height of the inlet channel is 0.24 m. Four different flow rates were used in this experiment:10.67, 14.55, 19.40, and 25.22 liters per second, respectively.Results and DiscussionIn the present study, the flow behavior within different sections of the vortex drop structure, includingthe inlet channel, the spiral inlet structure, and the outlet channel (energy dissipator), was investigated.Subsequently, the influence of three parameters including: flow rate (Q), inlet structure diameter (d), and theratio of sump depth to shaft diameter (Hs/D) on the energy dissipation efficiency (EDE) was examined. Theeffect of these parameters was evaluated in three stages: first, each parameter was assessed individually, then in pairwise combinations, and finally all three parameters were evaluated together.The results indicate that flow rate had the greatest influence on EDE. The highest efficiency (92.79%) occurred at a flow rate of 10.67 L/s, while the lowest (88.93%) corresponded to 25.22 L/s. Consequently, EDE was found to decrease with increasing flow rate.The simultaneous effect of all three parameters (diameter, flow rate, and sump depth) on energy dissipation efficiency shows that, for a 12 cm diameter and a flow rate of 10.67 L/s, the highest efficiency of 94.59% corresponds to Hs/D=1. For the same diameter and a flow rate of 25.22 L/s, the highest efficiency is 88.92% for Hs/D=1. For a 16 cm diameter and a flow rate of 10.67 L/s, the highest efficiency is 94.08% for Hs/D=1. For this same diameter and a flow rate of 25.22 L/s, the highest efficiency is 90.35% for Hs/D=2.ConclusionsIn the present research, a physical model of a sewer vortex drop shaft with a spiral inlet was investigated in the Hydraulic Structures Laboratory at Shahid Bahonar University of Kerman. This study examined the effect of three parameters including discharge (Q), the diameter of the inlet structure (d) and the ratio of the depth of sump to the drop shaft diameter (HS/D) on energy dissipation efficiency (EDE). Separate analysis of the individual parameters revealed that the influence of flow discharge (Q) on EDE was greater than that of the other two parameters (diameter and sump depth ratio), accounting for 79.92% of the effect. The two-parameter analysis concerning the interaction of diameter and discharge on EDE showed that at a discharge of Q=10.67 L/s, the highest EDE (93.15%) was achieved with a 12 cm diameter. Furthermore, when the discharge increased to Q=25.22 L/s, the maximum EDE (89.25%) was recorded for the 16 cm diameter. Regarding the combined effect of diameter and sump depth ratio on EDE, the results indicated that for a 12 cm diameter, the peak EDE (92.21%) occurred when HS/D=1, meaning the sump depth was equal to the drop shaft diameter.The results of this study confirm that all three parameters—flow discharge, inlet diameter, and sump depth—affect the energy dissipation efficiency (EDE), with flow discharge exerting the greatest influence. Future work should investigate the effect of other geometric parameters of the spiral inlet, particularly the slope of the inlet channel bed and the slope of the inlet structure itself, on the EDE of vortex drop shafts.Keywords: Energy dissipation efficiency, Discharge, Vortex drop structure, Laboratory model, Spiral inlet.AcknowledgmentsThe authors would like to thank all participants of the present study, especially the civil engineering department of the Shahid Bahonar University of Kerman which made this research possible.Conflict of InterestThe authors declared no potential conflicts of interest concerning the research, authorship, and publication of this article.FundingThe authors received no financial support for the research, authorship, and publication of this article .Data Availability StatementsData Availability Statement: All information and results are presented in the text of the article.Authors’ contributionAll authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by all authors. The first draft of the manuscript was written by E. F.K. and all authors commented on previous versions of the manuscript (S. A.Z., E. F.K., and M. Gh.H.). The final revisions have been applied by E. F.K., and M. Gh.H. Moreover, all authors have read and approved the final manuscript.
Original Article
Irrigation network management
Shima Azadeh Ranjbar; Majid Kholghi; Afshin َAshrafzadeh
Abstract
Extended AbstractIntroductionIn countries such as Iran, where drinking water, agriculture, and industry heavily rely on groundwater resources, management and protection are fundamental priorities. Excessive extraction has caused severe decline in groundwater levels and water quality reduction. Given ...
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Extended AbstractIntroductionIn countries such as Iran, where drinking water, agriculture, and industry heavily rely on groundwater resources, management and protection are fundamental priorities. Excessive extraction has caused severe decline in groundwater levels and water quality reduction. Given increasing population and surface water shortage, dependence on quality groundwater has intensified significantly.The Qazvin Plain, as a major agricultural and industrial hub, plays an effective role in regional food security and economic development. Agricultural and industrial activities have imposed increasing pressure on water resources. Although part of water demand is supplied through the Taleghan Dam and seasonal rivers, this plain has severe dependence on groundwater with increasing extraction, leading to level decline and serious quality challenges.The Qazvin Plain is located within 49°10' to 50°40' East longitude and 35°20' to 36°31' North latitude. The plain area is 5059.3 square kilometers with elevation ranging between 1131 and 2902 meters. With semi-arid climate, it receives average annual precipitation of 317 millimeters. With 250,000 hectares of agricultural land, the agricultural sector accounts for more than 85 percent of water consumption. The objective is to classify groundwater quality for agricultural, drinking, and industrial uses, and investigate spatial and temporal variations over a 20-year period from 2001 to 2021.MethodologyGroundwater quality data were obtained from Qazvin Regional Water Company. Water type and facies were determined using the Piper diagram. Qualitative classification for agricultural purposes was conducted according to Wilcox classification, for drinking according to Schoeller classification, and for industrial purposes using Langelier Saturation Index (LSI). The Wilcox method classifies water based on electrical conductivity (EC) and sodium adsorption ratio (SAR) into four classes: excellent, good, average, and unsuitable. Schoeller method classifies water into six classes based on total dissolved solids (TDS) and total hardness (TH). Langelier index categorizes water as corrosive (LSI<0), balanced (LSI=0), or scaling (LSI>0). Spatial and temporal zoning maps were prepared using Kriging interpolation in GIS at five-year intervals.Results and DiscussionPiper diagrams analysis over five periods (2001-2021) revealed continuous aquifer degradation. In 2001, most samples showed calcium-bicarbonate facies indicating fresh water. By 2006, samples shifted toward calcium-sulfate facies. In 2011, degradation accelerated with dramatic dispersion increase and sodium-chloride facies emergence indicating serious salinization. By 2016, critical condition became evident with high facies diversity. In 2021, crisis peaked with maximum dispersion, where calcium-bicarbonate facies appeared only in limited samples, and significant portions showed saline facies dominated by sodium-chloride and sodium-sulfate.For agricultural water quality, no sample was excellent quality. Good quality decreased from 25.25% in 2001 to 17.91% in 2021 (29% reduction). Average quality increased from 46.46% to 58.95%, and unsuitable samples fluctuated between 14.23% and 33.33%. Medium and unsuitable categories comprised 75 to 92 percent.For drinking water quality, about 70% of samples remained in good to average categories, but good quality decreased from 29% to 22%. Completely inappropriate category increased from zero to 2.74%. In total hardness, good quality declined from 39% to 24%, while acceptable water increased to 44%.For industrial water quality, significant changes occurred. Corrosive water decreased from 96.97% to 70.1%, while scaling water increased dramatically from 2.02% to 23.1%. Balanced water comprised only 1 to 6.7%. More than 93% falls into corrosive or scaling categories, requiring treatment before use.Spatial-temporal analysis revealed northern areas had best quality while southern areas faced worst quality, with degradation advancing from south to north. For agriculture, medium and unsuitable water increased from 75% to over 90%. For drinking, good quality decreased from 29-39% to 22-24%. For industry, over 93% are either corrosive or scaling.ConclusionsGroundwater resources show concerning degradation trends. Facies evolution from fresh to saline types, dramatic diversity increase, and significant reduction in suitable quality represent serious warnings.For agriculture, unsuitable water increased from 75% to over 90%, necessitating urgent strategies including extraction control, cropping pattern modification, and drainage systems development. For drinking, good quality decreased from 29-39% to 22-24%, with southern areas requiring advanced treatment. For industry, more than 93% are corrosive or scaling, requiring treatment.The spatial pattern indicates degradation advancing from south to north. The trend shows increasing salinity and hardness resulting from excessive extraction, reduced recharge, and likely saline water intrusion. This requires urgent actions including extraction control, artificial recharge enhancement, agricultural return flows treatment, and pollution prevention. Without fundamental measures, sustainability will be severely threatened.Keywords: Langelier index, Piper, Qazvin aquifer, Quality zoning, Schoeller, Wilcox.AcknowledgmentsThe authors wish to express their sincere gratitude to the Editor and the two anonymous reviewers for their insightful comments and constructive feedback, which significantly improved the quality of this manuscript. We also thank the Regional Water Company of Qazvin for providing the necessary data for this research.Conflict of InterestThe authors declared no potential conflicts of interest concerning the research, authorship, and publication of this article. Confirmation. FundingThe authors received no financial support for the research, authorship, and publication of this article.Data Availability StatementsThe datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.Authors’ contributionAll authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts. Sh. AR. handled the methodology, formal analysis, investigation, data curation, visualization, and initial draft preparation. A.A. and M. Kh. provided supervision and validation for the study. Resources were provided by M. Kh., A. A., and M. Kh. shared responsibility for the final review and editing of the manuscript. All authors have read and agreed to the published version of the manuscript.
Original Article
Irrigation network management
Mansour Jahantigh; Moien Jahantigh
Abstract
Extended AbstractIntroduction Currently, water shortage is one of the challenges that has affected many regions, especially arid areas, due to population growth and irrational and unscientific use of water. So that excessive use of water from wells, the groundwater ...
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Extended AbstractIntroduction Currently, water shortage is one of the challenges that has affected many regions, especially arid areas, due to population growth and irrational and unscientific use of water. So that excessive use of water from wells, the groundwater level has been lowered significantly, resulting in a decrease in the water flow of aqueducts and wells, and even the loss of some of these water resources. In order to solve the problem of water scarcity for various purposes such as providing agricultural water resources, permeability water into the groundwater table, increasing the vegetation cover, improving the environment, etc., earthen dams have been constructed in some susceptible areas, including arid regions. However, sedimentation in the reservoirs of these structures and subsequent disruption of the rate of infiltration into the ground is one of the problems that the construction of such dams brings. On the other hand, the factors that disrupt the infiltration of water into the groundwater table are sedimentation in the reservoirs of these earthen dams, which in some places turn into evaporation ponds due to the accumulation of sediment inside their reservoirs. Sedimentation of materials inside dam reservoirs is the result of sedimentation of materials carried by tributaries and reduces their permeability capacity. The intensity of this sedimentation process depends on the roughness of the watershed, its use, soil types, and the intensity and duration of rainfall. The type and location of the reservoir, as well as the hydrological regime of the river, also play an important role in this regard. So that their capacity may be reduced by up to 80 percent and cause the reservoir to lose its water storage function. In addition to the fact that these sediments play an effective role in reducing the volume of reservoirs, another important aspect is their pollution. The chemical composition of the sediments depends on the type of soils in the watershed, their agricultural use, and also the type of industry in the region. Considering that Sistan is one of the regions facing a water crisis and that numerous earthen dams have been constructed in its western highlands, there is a need to investigate the performance of these structures regarding their permeability status with the witness area so that, if necessary, reforms can be made for their optimal exploitation. Therefore, this research was conducted in the reservoirs of dams constructed in the western highlands of Sistan. MethodologyTo carry out this experiment, five earthen dams in the region, which were constructed in the 1970s, were selected and the amount of aging infiltration from the reservoir of these constructed dams and the control area was measured at different depths based on the standard double cylinder method at different times. By sampling the soil of the studied treatments, the physical properties of the soil samples were also determined.Results and DiscussionThe results showed that the infiltration rate in the control area was on average 1.2 times higher than the reservoir of the constructed dams, which showed a significant difference at the one percent level. In addition, the cumulative infiltration of the control area was also higher than that of the dam reservoirs and was statistically significant at the 5% level (p ≤ 0.05). In examining the effect of accumulated sediments on soil particle size distribution, the findings showed that the percentage of clay, silt, and sand in the soil of earthen dam reservoirs had a significant difference compared to the control area at sampling depths (p ≤ 0.05). The percentage of clay and silt increased by 14.2 and 3.2 times, respectively, compared to the control area, which consequently caused a change in soil texture from sandy class (control area) to clay loam in the earthen dam reservoir. Changes in the weighted average diameter (MWD) index in the studied treatments also indicated an 18-fold decrease in this index in the earthen dam reservoir compared to the control area. The results of multiple regression analysis to determine the most important factors affecting soil permeability also indicated that the percentage of sand accounted for 96% of the changes in soil permeability in the studied treatments. Conclusions The construction of an earthen dam increases the recharge of underground aquifers, which has a favorable effect on the water supply of wells and aqueducts, which in turn plays an effective role in increasing employment generation, improving the living conditions of watershed residents, and reducing their socio-economic problems. However, due to the lack of proper management of the sediments accumulated in the reservoirs of these dams, after several floods entered the reservoirs of these dams, their permeability has decreased significantly, and after a few years of water withdrawal, their reservoirs have become evaporation ponds, and a large part of the water entering these reservoirs evaporates and becomes unavailable without being used. The results of this study also showed that with the accumulation of sediments resulting from the entry of floods into these areas and the change in the physical properties and stability indices of soil aggregates, the permeability of these areas has decreased significantly. In addition, with the accumulation of sediments in the reservoirs of dams and their rising levels, their overflows are easily destroyed, which has led to the intensification of water erosion in the studied areas.Keywords: Artificial infiltration, Flood, Sediment, Soil physical properties, Water penetration into the soil. AcknowledgementThe authors would like to thank all participants of the present study.Conflict of InterestThe authors declared no potential conflicts of interest concerning the research, authorship, and publication of this article. Confirmation.FundingThe authors received no financial support for the research, authorship, and publication of this article.Data Availability StatementsThe datasets generated and/or analyzed during the current study are available from the corresponding author on reasonable request.Authors’ contributionAuthors have read and agreed to the published version of the manuscript. Authors contributed equally to the conceptualization of the article and writing of the original and subsequent drafts.
Review paper
Water Government
Nader Abbasi
Abstract
Extended AbstractIntroduction The accelerated and multidimensional growth of the contemporary world in both technical and social domains has significantly increased the complexity of human interactions—among individuals and with nature. Consequently, the concept of development, once primarily examined ...
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Extended AbstractIntroduction The accelerated and multidimensional growth of the contemporary world in both technical and social domains has significantly increased the complexity of human interactions—among individuals and with nature. Consequently, the concept of development, once primarily examined through an engineering lens, has evolved into a comprehensive paradigm encompassing technological, economic, social, political, environmental, and governance dimensions (Rosely and Voulvoulis, 2024). This paradigm emphasizes equity and sustainability, particularly the resilience of ecosystems. In domains such as water resource management, where human needs and behaviors intersect with ecological requirements and the carrying capacity of nature, this shift in perspective assumes heightened importance. Systems thinking offers a holistic framework that conceptualizes issues as interconnected systems. It accounts for the interactions among components, the multi-causality of events, foresight, dynamism, and the outcome-oriented nature of actions, while integrating technical, environmental, and social considerations. Although the importance of systems thinking in managing the complexities facing the world has now become apparent and has been more or less noticed in recent years, it is still in the educational and cultural stages, and its application to various issues has not been fully operationalized (Ross and Wade, 2024). Therefore, it seems that it is very necessary to explain the necessity and importance of this approach in solving today's complex problems, including water resources management, especially in Iran. This article attempts to briefly introduce the principles and foundations of the system and systems thinking, mention some global experiences, explain its role and position in the management and engineering of Iranian water resources, and present strategies and suggestions in this regard. Methodology This study begins by reviewing the complexities of contemporary phenomena, with particular emphasis on water management. It then outlines the principles and foundations of systems thinking, highlighting the necessity of adopting systems thinking approaches in water management and engineering. Subsequently, it introduces methods and tools for systemic analysis of water resources and presents selected global experiences in applying this approach. The analysis then turns to Iran’s water resources, employing the iceberg model as a systems tool. Within this framework, water-related challenges are examined across four conceptual layers: events, patterns, structures, and mental models, with illustrative examples provided at each level as follows (Senge, 1990; McLean et al., 2019; Kim, 1994).Events include phenomena such as the sharp decline in dam and well water levels, the reduction of potable water reserves, the drying of wetlands and rivers, the occurrence of land subsidence, the deterioration of water quality, the decline in agricultural production, and the intensification of social and security tensions.Patterns encompass recurring trends such as declining groundwater levels, rising salinity of water and soil, shifts in climatic indicators (temperature and precipitation), expansion of cultivated land and water consumption, and the growth of supply-driven activities.Structures refer to institutional and policy-related issues, including the multiplicity of water authorities, inefficiencies in allocation systems, subsidy and export policies, weaknesses in legislation, and the predominance of structural (engineering) solutions.Mental models capture underlying beliefs and assumptions, such as the absence of systemic thinking, the perception of water resources as inexhaustible, prioritization of sectoral and regional interests, and the pursuit of production irrespective of land-use planning and water availability. These factors are identified as root causes of structural inefficiency, reinforcing problematic trends and triggering adverse events.ResultsStudies on Iran’s water resources show that the country’s water crisis is no longer merely a scientific warning. Its symptoms—such as water scarcity, land subsidence, and the drying of dams, wells, wetlands, and rivers—are now visible to everyone. The situation has moved beyond abstract indicators and has become a serious issue with social, economic, and even security implications. The analysis conducted in this study using the Iceberg Model indicates that although natural and climatic factors contribute to the crisis, the core of the problem lies in water management practices, institutional structures, and development mindsets shaped over recent decades. Water management in Iran has largely focused on maximizing extraction, and the absence of a systems thinking in policymaking has led to the challenges we face today. Many current events stem from repetitive patterns and fragmented decision‑making in the past, whereas sustainable water management requires a comprehensive, forward‑looking approach that recognizes the interactions and mutual impacts among different components of the system. Furthermore, the paper proposes solutions tailored to each layer, prioritized from the deepest level upward: reforming beliefs and rethinking mental models, restructuring institutions and governance, and implementing adaptive, preventive, and remedial measures. Finally, the transition from traditional approaches to systems thinking is proposed as the fundamental step and the cornerstone of any effective and sustainable reform across all layers. ConclusionThe analysis also shows that addressing Iran’s water crisis requires looking beyond surface‑level symptoms and focusing on the deeper structural and cognitive roots of the problem. This means that merely changing policies or launching new projects will not be sufficient. Instead, fundamental shifts in values, mindsets, and institutional structures are necessary. Without transformation at these deeper levels, resolving the water crisis will not be possible. Furthermore, considering the points discussed, it can be concluded that Iran’s water crisis is a multidimensional national challenge, and the most fundamental step is shifting from fragmented, sector‑based thinking to a holistic, systems‑thinking approach. Global experiences show that systems thinking in water resources management provides a comprehensive framework that, through integrated and basin‑level management, stakeholder and local community participation, the use of systemic analytical tools, and attention to social and ecological resilience, enables participatory decision‑making and sustainable policymaking. Given these experiences and the current conditions of water resources—especially in arid and semi‑arid regions—it is clear that transitioning from sectoral and infrastructure‑focused management to a system‑based approach is not merely an option but a vital necessity for ensuring the long‑term sustainability of water resources.• Events include phenomena such as the sharp decline in dam and well water levels, the reduction of potable water reserves, the drying of wetlands and rivers, the occurrence of land subsidence, the deterioration of water quality, the decline in agricultural production, and the intensification of social and security tensions.• Patterns encompass recurring trends such as declining groundwater levels, rising salinity of water and soil, shifts in climatic indicators (temperature and precipitation), expansion of cultivated land and water consumption, and the growth of supply-driven activities.• Structures refer to institutional and policy-related issues, including the multiplicity of water authorities, inefficiencies in allocation systems, subsidy and export policies, weaknesses in legislation, and the predominance of structural (engineering) solutions.• Mental models capture underlying beliefs and assumptions, such as the absence of systemic thinking, the perception of water resources as inexhaustible, prioritization of sectoral and regional interests, and the pursuit of production irrespective of land-use planning and water availability. These factors are identified as root causes of structural inefficiency, reinforcing problematic trends and triggering adverse events.Furthermore, the paper proposes solutions tailored to each layer, prioritized from the deepest level upward: reforming beliefs and rethinking mental models, restructuring institutions and governance, and implementing adaptive, preventive, and remedial measures. Finally, the transition from traditional approaches to systems thinking is proposed as the fundamental step and the cornerstone of any effective and sustainable reform across all layers.In summary, and considering the above, it can be said that Iran's water crisis is a multi-sectoral national challenge, and the most fundamental action is the decision to change the approach from a sectoral and detail-oriented approach to a holistic approach of systemic thinking.Global experiences have shown that systems thinking in water resources management is a comprehensive approach that, by emphasizing and relying on integrated and basin-wide management, stakeholder and local community participation, the use of systemic analytical tools, and attention to social and ecological resilience, enables participatory decision-making and sustainable policymaking.Thus, considering the existing experiences and the conditions governing the status of water resources and consumption, especially in arid and semi-arid regions of the world, it can be said that the transition from sectoral and structural management to a systemic approach is not a choice but a vital necessity for the sustainability of water resources.
Original Article
Geotechnic
Atefeh Arab; Hojjat Ahmadi; NourAli Haghdoust; Bahram Nourani
Abstract
Extended AbstractIntroduction Earth dams are the most common type of dams due to their cost-effectiveness, and they make up the majority of the world's dams. Water seepage is one of the most important issues in the design and safety of earth dams, as it can lead to ...
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Extended AbstractIntroduction Earth dams are the most common type of dams due to their cost-effectiveness, and they make up the majority of the world's dams. Water seepage is one of the most important issues in the design and safety of earth dams, as it can lead to increased pore water pressure, reduced shear strength, the occurrence of piping phenomena, and ultimately dam failure. Statistics show that approximately 35% of dam failures are directly or indirectly related to seepage. This risk is particularly exacerbated in dams built on permeable alluvial foundations.To control seepage, various measures are employed, including drainage systems in the dam body and foundation. Blanket drains, toe drain, and chimney drain, whose main roles are to collect leaked water, reduce pore water pressure, and lower the water table. Although the use of chimney drains has become more common in recent years, new studies show that horizontal drains, especially their length, can have a significant impact on reducing pore water pressure and improving dam stability, while parameters such as drain thickness, height, and angle play a lesser role.Seepage in earth dams is examined using numerical and experimental methods. Numerical methods are fast and cost-effective, but laboratory studies are of high importance as a basis for validating numerical results and for a detailed examination of the dam's actual behavior. Given that the impact of different drainage geometries with the same length has not been fully investigated to date, this study designs a laboratory model of a homogeneous earth dam to examine the effect of various drainage types with equal lengths and different geometries on seepage discharge and flow patterns in an earth dam located on an alluvial bed.MethodologyIn this study, a homogeneous earth dam was constructed using glass bead material, which contains glass particles with sizes ranging from 0.7 to 3.5 millimeters. The dam model was designed in a drainage box with dimensions of 150 cm length, 10 cm width, and 60 cm height, and included 5 piezometers to monitor changes in pore water pressure under the dam structure. The purpose of this experiment was to investigate the effect of the downstream drain's geometric shape on seepage from the dam. To observe the water seepage, artificial sunset yellow dye and potassium permanganate were used to visualize the flow lines. An air tank was also placed above the laboratory box to keep the water level in the dam constant.The hydraulic conductivity of the material was estimated to be 0.128 cm/s using the constant head permeability test. The height of the constructed dam was 25 cm above the level of the permeable layer, which, considering the location of the overflow weirs, resulted in a reservoir water level of approximately 22 cm. The crest width was 10 centimeters, and the upstream and downstream body slopes were equal to the dam width at the foundation, which was 130 centimeters. Figure 1 illustrate the details of the constructed dam.To study the effects of different drain system and their geometry, three different drain system involving blanket, toe and chimney drain were studied and compared with the basic state of an earth dam with no drain system. The length of all implemented drains was almost identical equal to 21 cm. The dimensions of the drains were presented in table1. The coarse gravel was used to create the employed drains. To avoid any mixing of the fine glass beads within the coarse materials of drains, a fine mesh fabric was placed around the drain system. The thickness of the gravels in the drains was 3 cm. Results and Discussion The summery of the achieved results were presented in figure 2 in terms of pore pressure in the base of the dam. In this figure each curve belongs to the specific drain. As seen, the toe and blanket drains have similar effect in removing of pore water pressure, while the chimney drain is very effective, comparing to other drain.Additionally, the seepage line was investigated in the toe and blanket types to evaluate the seepage velocity and their lengths. The results are shown in figure 3. As seen in this figure, the seepage path through the earth dam from the identical inlet point has different outlet point. The length of the seepage path in toe drain and blanket drain significantly is shorter than that in no-drain. Among toe drain, blanket drain, and chimney drain , the toe drain has the shortest seepage path.ConclusionsThe objective of this study is to evaluate the performance of various drainage systems in controlling seepage and mitigating pore water pressure within a homogeneous earthen dam constructed on an alluvial foundation under laboratory conditions. To quantitatively assess the influence of drainage systems on the seepage rate and the dam's hydraulic behavior, three drain configurations: horizontal or blanket drains, toe drains, and chimney drains, were investigated. Their performance was subsequently compared to a control scenario with no drainage system. The findings of this investigation demonstrate that chimney drains are superior comparing to other drain types in reducing pore water pressure; however, they concurrently lead to a higher rate of seepage. When drain length is held constant, horizontal drains are preferable to toe drains. Nevertheless, the implementation of toe drains can enhance the structural stability of the dam body due to the incorporation of a substantial volume of coarse-grained material. This particular aspect, however, warrants further investigation to enable a quantitative comparison of its outcomes with those of other drainage configurations. Based on a value analysis conducted by considering three parameters—pore water pressure reduction, seepage discharge, and the volume of material utilized as a cost factor—the chimney drain yields the highest value, whereas the toe drain yields the lowest. It is noteworthy that the differential in value between the chimney drain and the toe drain is marginal.
