Water resources planning and management based on system dynamics: a case study of Yulin city

Water security is an integral aspect of the socio-economic development in China. Nevertheless, water resources are under persistent pressures because of the growing population, heavy irrigation, climate change effects and short-term policies. Traditional management approaches narrowly focus on increasing supply and reducing demand without considering the complex interactions and feedback loops that govern water resource behaviour. Whereas these approaches may provide quick fix solutions, they often lead to unanticipated, sometimes catastrophic, delayed outcomes. Therefore, water management needs to take a holistic approach that caters to the interdependent physical (e.g. water inflows, outflows) and behavioural (e.g. decision rules, perceptions) processes in the system. Unlike reductionist approaches, System Dynamics (SD) takes a system-level view for modelling and analysing the complex structure (cause–effect relationships, feedback loops, delays) that generates the systemic behaviour. Simulating the SD model allows assessing long-term system-wide impacts, exploring leverage points and communicating results to decision makers. In this paper, we follow an SD modelling approach to examine the future of water security in Yulin City. First, we present a conceptual model for integrating water supply and demand. Based on this, we build an SD model to simulate and analyse the dynamics of water resource over time. The model output is tested to ensure that it satisfactorily replicates the historical behaviour of the system. The model is used to quantitatively assess the effectiveness of various supply/demand management options. Three scenarios are designed and examined: business-as-usual, supply management, and demand management. Results show that current management regime cannot effectively meet the future water demand. Whereas supply acquisition provides short-term benefits, it cannot cope with the growing population. A combination of conservation measures and demand-management instruments is regarded the most effective strategy for balancing supply and demand.     

Climate change impacts on irrigation water requirements in the Guadalquivir river basin in Spain

Irrigated production in the Guadalquivir river basin in Spain has grown significantly over the last decade. As a consequence, water resources are under severe pressure, with an increasing deficit between available supplies and water demand. To conserve supplies, the water authority has reduced the volume of water assigned to each irrigation district. Major infrastructural investments have also been made to improve irrigation efficiency, including the adoption of high technology micro-irrigation systems. Within a context of increasing water scarcity, climate change threatens to exacerbate the current supply-demand imbalance. In this study, the impacts of climate change on irrigation water demand have been modelled and mapped. Using a combination of crop and geographic information systems, maps showing the predicted spatial impacts of changes in agroclimate (climate variables that determine the irrigation requirements) and irrigation need have been produced. The maps highlight a significant predicted increase in aridity and irrigation need. Modelling of irrigation water requirements shows a typical increase of between 15 and 20% in seasonal irrigation need by the 2050s, depending on location and cropping pattern, coupled with changes in seasonal timing of demand.     

Virtual water trade in industrial products: evidence from Malaysia

Virtual water embodied in international trade is equivalent to nearly one-third of global water withdrawal, confirming that trade plays a significant role in redistributing global water resources. This paper extends a virtual water analysis by measuring the extent to which virtual water embodied in traded industrial products affects the distribution of global virtual water. The distribution of global virtual water can be improved if trade in industrial products promotes virtual water outflows from water-abundant to water-scarce countries. Analyses were performed using an input–output model that can decompose water consumption into domestic demand and exports by destinations of trade. Focusing on Malaysia, the results indicate that trade in industrial products between Malaysia and its main trading partners have a limited capacity to improve the distribution of global virtual water. This limitation can be due to two reasons. Firstly, exports of Malaysian industrial products are mainly driven by less water-intensive sectors. Therefore, the amount of virtual water that outflows into other countries is also low. Secondly, trade in Malaysian industrial products largely involves water flows with other water-abundant countries. Only several water-scarce countries benefit from virtual water trade in industrial products with Malaysia, namely the Netherlands, Australia and China.     

Whale watch or no watch: the Australian whale watching tourism industry and climate change

Whale watching is a billion dollar industry worldwide. One of the most popular species for whale watching is the humpback whale (Megaptera novaeangliae). The migratory corridors, feeding, resting and calving sites which are used for whale watching may be influenced by changing ocean currents and water temperatures. Here, we used an innovative approach addressing the emerging issue of climate change on the whale watch industry. This involved participatory modelling using key stakeholders for the whale watching industry to develop a systems conceptualisation model for evaluating the potential effects of climate change based on a case study from the east coast of Australia. This participatory approach allowed us to identify the causal linkages (including feedback pathways) between different “Elements” of the system within which the whale watching industry operates. It also allowed us to integrate multiple drivers covering socio-economic and environmental aspects including climate change (e.g. temperature), policy (e.g. number of boats), ecology (e.g. number of whales) and socio-economics (e.g. number of tourists) to evaluate the changes in the overall system. We then developed a Bayesian belief network model from the systems conceptualisation on which stakeholders identified a priority issue (Profitability). Stakeholders provided the structure and the quantification of this model, and a sensitivity analysis was carried out to help identify important intervention points for the industry. Overall, our research illustrates how such a modelling process can assist local tourism operators and authorities in making rational management decisions within a holistic or systems-based framework and its approach is applicable to other regions.     

湖泊流域系统水文水动力联合模拟研究进展综述

湖泊流域水文水动力联合模拟对综合管理湖泊流域水资源具有重要的理论和实践意义。通过水文水动力联合模拟研究进展的综述,可深入了解湖泊流域联合模型发展和演变过程,把握国际研究主流趋势和前沿手段。传统湖泊流域联合模拟方法主要通过流域水文模型结合湖泊水量平衡模型来计算湖泊流域水均衡组分,但水量平衡方法仅是对湖泊过程的一般性描述,难以切实反映水位空间差异显著的湖泊系统有着显著的水动力特性。基于流域水文模型与湖泊水动力模型的联合系统克服了大尺度湖泊流域系统难以切实描述和完整模拟的难点,在湖泊流域系统水资源管理与调控中发挥了重要作用。系统概述了国内外不同尺度湖泊流域系统水文水动力联合模拟研究,归纳总结了基于外部耦合、内部耦合与全耦合技术的联合模型的优势和不足。从学科发展趋势和应用需求的角度出发,概述了湖泊流域系统联合模拟的难点和今后发展趋势     

An integrated modelling system for investigating the benefits of catchment management

Complex natural resource degradation problems such as dryland salinisation require integrated management solutions. Integrated catchment modelling can be used to develop such solutions. This paper presents three models that were applied independently in the Liverpool Plains Catchment, an important crop production area, in Eastern Australia. They are a point soil-plant-water model, an economic catchment model, and a catchment hydrology model. After discussing their individual merits and limitations, the paper develops the concept of a holistic modelling framework by combining these models to gain synergy effects in analytical ability as well as applicability and implementation of results.     

Developing a sustainability assessment framework for integrated management of water resources systems using distributed zoning and system dynamics approaches

The management of large-scale water resources systems requires including of different stakeholders and users from municipal, agricultural, industrial and environmental sectors. This has baffled the process of decision making for integrated water resource systems. In such systems, the interactions between various stakeholders must be carefully taken into account with the goal of aggregating interests around the sustainability concept. In this study, first, the integrated water resources systems of Big Karun Watershed, Iran, have been modeled using the system dynamics approach. The system dynamics model represents the interactions between different components of the system, including water transfer projects, dams, urban, industry, agriculture and fish farming, and environmental demands. Vensim software has been used for the system dynamics modeling. Vensim simulates the dynamics behavior of the sub-systems and overall performance of the system by comparing the current operation policies with the future management scenarios. A wide range of performance indices, such as quantitative and qualitative water stress, income, cost, and productivity, have been used here to represent different aspects of sustainability goals. Finally, the performance of the systems has been evaluated by developing a sustainability index using distributed zoning model in order to identify proper management policies for this watershed. The results indicate that downstream users demand cannot be fully met by solely considering inter-basin water transfer and agricultural development projects. The sustainable and integrated management of the whole system ties into enhancement in both infrastructure systems and the operation of the whole system. It is expected that the sustainability of the basin improves if a water market schema exists and the gained money would be used to enhance the efficiency of existing irrigation networks.

     

A reassessment of energy and GDP relationship: the case of Australia

This paper investigates the long- and short-run relationships between energy consumption and economic growth in Australia using the bound testing and the ARDL approach. The analytical framework utilized in this paper includes both production and demand side models and a unified model comprising both production and demand side variables. The energy–GDP relationships are investigated at aggregate as well as several disaggregated energy categories, such as coal, oil, gas and electricity. The possibilities of one or more structural break(s) in the data series are examined by applying the recent advances in techniques. We find that the results of the cointegration tests could be affected by the structural break(s) in the data. It is, therefore, crucial to incorporate the information on structural break(s) in the subsequent modelling and inferences. Moreover, neither the production side nor the demand side framework alone can provide sufficient information to draw an ultimate conclusion on the cointegration and causal direction between energy and output. When alternative frameworks and structural break(s) in time series are explored properly, strong evidence of a bidirectional relationship between energy and output can be observed. The finding is true at both the aggregate and the disaggregate levels of energy consumption.     

Discovering and characterizing farm households’ resilience under water scarcity

Water scarcity at an alarming rate has been a limiting factor for sustainable agriculture in arid and semi-arid environments of the world. It has resulted in a number of problems such as poverty and food insecurity among farm households. Therefore, building and improving resilience, as a way to mitigate the impacts of water scarcity, is important for farm households. But one of the significant steps for planning to improve farm households’ resilience under water scarcity is investigation of the current level of resilience of these households and understanding their variances. Therefore, this study offers a classification of farm households’ diversity based on resilience. Primary data were collected from 260 randomly selected farm households in 21 villages around Parishan wetland, Iran. Farm Household Resilience Scale was used to measure resilience. Cluster analysis suggested three groups: highly, medium-, and low-resilient farm households. The results of comparing three groups revealed that highly resilient farm households characterize with higher risk management, more agricultural water security, more positive psychological traits, and better knowledge management. Also, they had better water quality, attended more agricultural extension activities, and used modern irrigation systems. Farm households’ resilience map using GIS software illustrated that there is a relationship between resilience and farm location from the wetland. The findings of this study could be used by planner and policy-makers to improve farm households’ resilience in arid and semi-arid environments. Improvement in knowledge management system is recommended as one of the most effective policy instruments in building resilience.     

虚拟水贸易的可计算非线性动态投入产出分析模型

虚拟水是水资源需求管理的创新领域。投入产出法是研究虚拟水的重要方法,但既有研究多以线性静态投入产出模型为主,存在较强的比例性假设,在解释现实经济活动中的虚拟水贸易时存在一定缺陷和不足。为更加贴近现实状况,本文利用可计算一般均衡(CGE)思想,设计了一种新的虚拟水测算思路,对传统的线性静态投入产出模型进行了非线性和动态化的拓展,旨在对区域经济系统中的虚拟水贸易进行更加科学合理的计算和考察。首先,参照国家统计机构常用的42产业部门划分方式,根据一般均衡理论,围绕区域经济系统的生产模块、价格模块和供需平衡模块三个部分,定义有关变量和参数,对区域经济系统非线性动态投入产出模型进行了详细的方程列写。在此基础上,将虚拟水流动的因素与一般形式的非线性动态投入产出模型进行嵌套,采用"母表"(价值型流量表)和"子表"(水资源流量表)相结合的形式,给出了一种全新的区域水资源投入产出表的设计思路与编制方法,将可计算非线性动态产出模型从一般形式扩展至水资源领域,构建了区域经济系统中虚拟水贸易的可计算非线性动态投入产出分析框架。分析同时指出,通过对该模型进行求解,可以推导和计算平衡增长路径和最优增长路径下的区域经济系统产出结构和用水结构,并可结合虚拟水贸易对区域经济的作用机理,分析最优增长路径下实施虚拟水贸易对区域经济增长的贡献。     

Forecasting China’s primary energy demand based on an improved AI model

An improved energy demand forecasting model is built based on the autoregressive distributed lag (ARDL) bounds testing approach and an adaptive genetic algorithm (AGA) to obtain credible energy demand forecasting results. The ARDL bounds analysis is first employed to select the appropriate input variables of the energy demand model. After the existence of a cointegration relationship in the model is confirmed, the AGA is then employed to optimize the coefficients of both linear and quadratic forms with gross domestic product, economic structure, urbanization, and technological progress as the input variables. On the basis of historical annual data from 1985 to 2015, the simulation results indicate that the proposed model has greater accuracy and reliability than conventional optimization methods. The predicted results of the proposed model also demonstrate that China will demand approximately 4.9, 5.6, and 6.1 billion standard tons of coal equivalent in 2020, 2025, and 2030, respectively.     

Ecological and economic impacts of different irrigation and fertilization practices: case study of a watershed in the southern Iran

Best management practices, such as conservation tillage, the optimum level of irrigation, fertilization, are frequently used to reduce non-point source pollution from agricultural land and improve water quality. In this study, we used the soil and water assessment tool to model the impacts of different irrigation (adjusted to crop need), cropping and fertilization practices on total nitrogen loss. The economic impacts of these practices on crop net farm income were also evaluated. For this purpose, the model was calibrated through comparing model outputs with observations to ensure reliable hydrologic, crop yield and nitrate leaching simulations. The results showed that by reducing water or fertilizer or combination of both, we can reduce nitrate leaching. For wheat and corn, the best scenario was S1n1 (combination between reduction by 10 % of water and nitrogen fertilizer application, simultaneously) and S2n3 (combination of 20 and 30 % reduction in water and fertilizer application), respectively. These scenarios are both ecologically and economically desirable. Also, decreasing nitrogen fertilization by 50 % for corn would decrease the nitrate pollution from 101.1 to 32.3 kg N ha^?1; therefore, this strategy is ecologically desirable but economically unsound. So, there are opportunities for environmental decision makers to encourage farmers to implement these strategies. Also, since the nitrogen leaching cannot decrease without a reduction in net farm income for crops such as corn; hence, the losses of farmers should be compensated.     

Australian approaches to coastal vulnerability assessment

The Australian coastline is one of the longest and most diverse of any in the world, and Australian researchers have developed preliminary models of the behaviour of major coastal systems such as beaches and reefs. The Australian population is particularly focused along the coastline, especially in metropolitan centres; however, the population of regional centres along the coast is increasing steadily in response to a phenomenon termed seachange. Coastal systems are increasingly threatened by potential impacts as a result of climate change, as indicated by the successive assessments by the Intergovernmental Panel on Climate Change (IPCC). Although Australia played a central role in applying a common methodology (CM), developed from IPCC guidelines in the 1990s, and in devising alternative approaches, which were initially trialled at nine sites on the Australian coast, there has not been a nationally co-ordinated approach to assessing the coastal vulnerability of Australia, and such an approach is only emerging now. Instead, there have been a series of different approaches adopted to look at the different parts of the Australian coast, including wetland mapping in northern Australia; geomorphic unit mapping in South Australia; storm surge vulnerability modelling in Queensland; probabilistic approaches to beach erosion in New South Wales; indicative mapping of potential coastal retreat in Tasmania. Additionally, there have been methods proposed by insurers and coastal engineers to meet their requirements. Since 2005, the Australian government has once again seen the need for a national coastal vulnerability assessment, and a series of studies are planned or under way to achieve the aims of a National Climate Change Adaptation Framework.     

The relationship between climate and streamflow in the Namoi Basin

The Namoi River Basin (42 000 km²) is located in the Murray-Darling Basin, west of the Great Australian Dividing Range in northeast New South Wales (NSW), and includes some of the most fertile agricultural lands in Australia. One of the environmental concerns for this basin is erosion and its effects on downstream water quality. Models that relate climate, land use, and these concerns require measurements of climate (rainfall and temperature) and streamflow. These measurements were examined as a preliminary to the modelling. The residual mass technique was used to examine the temporal variation of annual rainfalls over the approximately 100 years of available data, and significant spatial variations were found in annual rainfall trends over the catchment. Streamflow was examined at key river gauging stations. The impact of recent large-scale irrigation operations was clearly observed. The impact of changing land use and land management on runoff ratios was examined for eight subcatchments. Temperature variations were examined for the four major towns in the catchment. The duration of the temperature data is too short to make any comments about long-term trends. Significant variations were observed in an east to west direction.     

湘南红壤丘陵区农户经济行为对土地退化的影响分析——以祁东县紫云村为例

通过在湖南省祁东县紫云材进行的土地利用及农户经济行为调查,从土地状况、从业选择、农具、农田设施、耕作方式和效益等方面,分析了湘南红壤丘陵区农户社会经济行为对土地质量的影响。结果表明：紫云村农户重“品种”轻“土壤”,水田土壤有机质含量减少,理化性状变差,土壤自然肥力降低,旱地、林地粗放经营,质量退化。改变农户只重“品种”而忽视“土壤”的观念、提高耕地复种指数、建立合理的轮作体系和水土保持型高效集约持续的耕作制度、加强林业管理和经营、加大农业投入、搞好农田水利建设是防止本区土地退化和保证本区农业可持续发展的对策。     

Intra-annual dynamics of water stress in the central Indian Highlands from 2002 to 2012

India’s continued development depends on the availability of adequate water. This paper applies a data-driven approach to estimate the intra-annual dynamics of water stress across the central Indian Highlands over the period 2002–2012. We investigate the spatial distribution of water demanding sectors including industry, domestic, irrigation, livestock and thermal power generation. We also examine the vulnerability of urban centers within the study area to water stress. We find that 74 % of the area of the central Indian Highlands experienced water stress (defined as demand exceeding supply) for 4 or more months out of the year. The rabi (winter) season irrigation drives the intra-annual water stress across the landscape. The Godavari basin experiences the most surface water stress while the Ganga and Narmada basins experience water stress due to groundwater deficits as a result of rabi irrigation. All urban centers experience water stress at some time during a year. Urban centers in the Godavari basin are considerably water stressed, for example, Achalpur, Nagpur and Chandrapur experience water stress 8 months out of the year. Irrigation dominates water use accounting for 95 % of the total water demand, with substantial increases in irrigated land over the last decade. Managing land use to promote hydrologic functions will become increasingly important as water stress increases.     

An empirical analysis on the impact of environmental regulations on pork trade: evidence from China

This paper uses the gravity model to examine the effect of environmental regulations on pork trade flows between different regions within China. We apply a linear programming tool to estimate pork trade flows from 2000 to 2008, and discuss the environmental acts on livestock pollution and income level to proxy environmental regulations. We use OLS regression and panel data with dummy variable in the cross-sectional GLS estimation. Our results indicate that the gap of environmental regulations between trade partners has a positive relationship with pork trade flows, and the difference in environmental regulations changes the traditional comparative advantage pattern to some extent. This paper provides convincing evidence for the pollution haven effect on livestock in China.     

Can ECOPATH with ECOSIM enhance models of radionuclide flows in food webs? An example for 14C in a coastal food web in the Baltic Sea

In this study it was evaluated whether the ECOPATH with ECOSIM software could be used as a platform to facilitate the construction of models and study of transport and accumulation of radionuclides in aquatic food webs. The evaluation was based upon a food web model of carbon (C) and carbon-14 ((14)C) flow for a coastal area in the Baltic Sea, the ECOPATH, the ECOSIM and the ECOTRACE models. The original carbon flows and assumptions were easily incorporated into the ECOPATH and ECOSIM modelling environment. The new model was also well suited to drive a (14)C flow model (ECOTRACE) for each of the organisms included. ECOTRACE estimated steady-state concentrations of (14)C that were between 73 and 142% of the original flows. The results clearly show that there is great potential for a successful development of this approach for integrating scientific knowledge about food webs and radioecological models for aquatic systems.     

An empirical analysis on the impact of environmental regulations on pork trade:evidence from China

This paper uses the gravity model to examine the effect of environmental regulations on pork trade flows between different regions within China.We apply a linear programming tool to estimate pork trade flows from 2000 to 2008,and discuss the environmental acts on livestock pollution and income level to proxy environmental regulations.We use OLS regression and panel data with dummy variable in the cross-sectional GLS estimation.Our results indicate that the gap of environmental regulations between trade partners has a positive relationship with pork trade flows,and the difference in environmental regulations changes the traditional comparative advantage pattern to some extent.This paper provides convincing evidence for the pollution haven effect on livestock in China.     

Partitioning of polar and non-polar neutral organic chemicals into human and cow milk

The aim of this work was to develop a predictive model for milk/water partition coefficients of neutral organic compounds. Batch experiments were performed for 119 diverse organic chemicals in human milk and raw and processed cow milk at 37°C. No differences (<0.3 log units) in the partition coefficients of these types of milk were observed. The polyparameter linear free energy relationship model fit the calibration data well (SD=0.22 log units). An experimental validation data set including hormones and hormone active compounds was predicted satisfactorily by the model. An alternative modelling approach based on log K(ow) revealed a poorer performance. The model presented here provides a significant improvement in predicting enrichment of potentially hazardous chemicals in milk. In combination with physiologically based pharmacokinetic modelling this improvement in the estimation of milk/water partitioning coefficients may allow a better risk assessment for a wide range of neutral organic chemicals.