Willingness to Pay for Improving the Residential Waste Disposal System in Korea: A Choice Experiment Study

This study attempts to apply choice experiments with regard to the residential waste disposal system (RWDS) in Korea by considering various attributes that are related to RWDS. Using data from a survey conducted on 492 households, the empirical analysis yields estimates of the willingness to pay for a clean food-waste collection facility, the collection of small items (such as obsolete mobile phones and add-ons for personal computers), and a more convenient large waste disposal system. The estimation results of multinomial logit models are quite similar to those of nested logit models. The results reveal that residents have preferences for the cleanliness of facilities and the collection of small items. In Korea, residents are required to purchase and attach stickers for the disposal of large items; they want to be able to obtain stickers at not only village offices but also supermarkets. On the other hand, the frequency of waste collection is not a significant factor in the choice of the improved waste management program.

Linking Riparian Dynamics and Groundwater: An Ecohydrologic Approach to Modeling Groundwater and Riparian Vegetation

The growing use of global freshwater supplies is increasing the need for improved modeling of the linkage between groundwater and riparian vegetation. Traditional groundwater models such as MODFLOW have been used to predict changes in regional groundwater levels, and thus riparian vegetation potential attributable to anthropogenic water use. This article describes an approach that improves on these modeling techniques through several innovations. First, evapotranspiration from riparian/wetland systems is modeled in a manner that more realistically reflects plant ecophysiology and vegetation complexity. In the authors’ model programs (RIP-ET and PRE-RIP-ET), the single, monotonically increasing evapotranspiration flux curve in traditional groundwater models is replaced with a set of ecophysiologically based curves, one for each plant functional group present. For each group, the curve simulates transpiration declines that occur both as water levels decline below rooting depths and as waters rise to levels that produce anoxic soil conditions. Accuracy is further improved by more effective spatial handling of vegetation distribution, which allows modeling of surface elevation and depth to water for multiple vegetation types within each large model cell. The use of RIP-ET in groundwater models can improve the accuracy of basin scale estimates of riparian evapotranspiration rates, riparian vegetation water requirements, and water budgets. Two case studies are used to demonstrate that RIP-ET produces significantly different evapotranspiration estimates than the traditional method. When combined with vegetation mapping and a supporting program (RIP-GIS), RIP-ET also enables predictions of riparian vegetation response to water use and development scenarios. The RIP-GIS program links the head distribution from MODFLOW with surface digital elevation models, producing moderate- to high-resolution depth-to-groundwater maps. Together with information on plant rooting depths, these can be used to predict vegetation response to water allocation decisions. The different evapotranspiration outcomes produced by traditional and RIP-ET approaches affect resulting interpretations of hydro-vegetation dynamics, including the effects of groundwater pumping stress on existing habitats, and thus affect subsequent policy decisions.     

基于选择实验法的支付意愿研究——以湘江水污染治理为例

论述了选择实验法的理论基础,运用该方法对湘江水污染治理中居民的支付意愿进行了实证分析,以此推断实施湘江流域水污染治理工程后湘江流域水质好转带来的环境价值。选择在湘江流域的八大城市布点,获取了587份居民的调查问卷数据资料。通过计量经济学分析,得到如果实施湘江流域水污染治理工程、彻底解决湘江重金属污染问题,水质完全达到或优于Ⅱ类水标准,湘江流域居民总的支付意愿为1074亿元。     

Groundwater quality: Responsible agriculture and public perceptions

The chief sources of groundwater contamination on farms come from point sources and diffuse sources. Possible point sources are feedlots, poorly-sited manure piles, septic sewage-treatment systems—all of which can release nitrate, phosphates and bacteria— and sites of chemical spills. Diffuse sources are typified by excess fertilizer leaching from a number of arable fields. The basis of quality standards for drinking-water is discussed in relation to common contaminants present on farms. Samples of drinking-water were collected in 1991–1992 from wells on about 1,200 farms in order to study the quality of rural groundwater in Ontario. Analysis showed that approximately one third of wells were contaminated with bacteria, 14% were contaminated with nitrate, two wells were contaminated with pesticide, but 40% were considered unsafe because of the presence of at least one contaminant. These values were similar to those reported for similar regions in the U.S. There was no significant effect of agricultural practice on the proportion of contaminated samples. One response of Ontario's farmers to information on water quality has been to initiate their own program, the Environmental Farm Plan, which has 23 modules by which the risk of environmental contamination can be assessed. Government policies for agriculture can be expected to influence farming practices. However, the literature suggests that the consequences of policies aimed at reducing environmental contamination are poorly understood, not least because the instruments used for implementation can have widely differing impacts. The need for discussions on the ethics surrounding the relationship between food producers and consumers with regard to environmental contamination is identified.     

Water-sensitive Urban Planning: Protecting Groundwater

Sustainable development requires the promulgation of guidelines for urban planning which consider the effects of the built environment on water resources. In this context, our paper focuses on the effects of urban development on the quantity and quality of rainwater which infiltrates into the soil on its way to recharge the aquifer. The paper includes: identification of the state of knowledge regarding the effect of urban development on runoff and infiltration; a case study-estimation of the effect of certain patterns of urban development in an Israeli neighbourhood,together with an option for mitigating them by relatively simple and inexpensive means; presentation of the components of urban planning which influence runoff and infiltration; and proposals for continuing research in this area which has been relatively neglected until recently.     

Contingent Valuation and Real Economic Commitments: A Private Good Experiment

The ultimate test of the accuracy of contingent valuation methods (CVM), in measuring benefits, is whether subjects will actually pay the amounts that they say they would be willing to pay in a CVM study. An experiment was conducted in which the maximum WTP of potential visitors to enter Warkworth Castle was compared against the acceptance of an entrance ticket at their stated CV price, thus providing a real monetary test of value and behavioural intention. Only 40% of potential visitors at the Castle gate were willing to make a real economic commitment following their CV WTP responses. Whilst the CVM results were found to be comparable with other CVM studies in terms of content and construct validity, they clearly failed a criterion validity test, even when the CVM survey was juxtaposed to the behavioural intention stage. CVM studies need to adopt stringent criteria in deciding the 'truthfulness' and 'legitimacy' of WTP responses, if CVM is to provide accurate and robust estimates of the value of environmental goods.     

Power,Fairness and Constrained Choice in Agricultural Markets: A Synthesizing Framework

The (un)fairness of agricultural markets is frequently invoked, especially by farmers. But fairness is difficult to define and measure. In this paper we link fairness and power with the concept of constrained choice to develop a framework for assessing fairness in agricultural markets. We use network exchange theory to define power from the dependencies that exist in agricultural networks. The structure of agricultural networks and the options that agricultural producers have to participate in agricultural networks affect the degree to which they are dependent on others within the network. Dependency, in turn, affects the choices that agricultural producers have. We consider both the number and nature of these choices. We argue that constraining or limiting choices—both in number and type—violates principles of justice. Importantly, network exchange theory provides a method for assessing constraints in choices and, hence, the fairness of agricultural markets. Such an assessment could potentially lead to new policies that safeguard the liberties of marketplace participants. We present a brief case to illustrate how this framework can inform on the fairness of agricultural markets and conclude with considerations of what this means for policy, particularly in the arena of anti-trust.     

Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin,Nevada1

Carroll, Rosemary W.H., Greg Pohll, David McGraw, Chris Garner, Anna Knust, Doug Boyle, Tim Minor, Scott Bassett, and Karl Pohlmann, 2010. Mason Valley Groundwater Model: Linking Surface Water and Groundwater in the Walker River Basin, Nevada. Journal of the American Water Resources Association (JAWRA) 46(3):554-573. DOI: 10.1111/j.1752-1688.2010.00434.x Abstract: An integrated surface water and groundwater model of Mason Valley, Nevada is constructed to replicate the movement of water throughout the different components of the demand side of water resources in the Walker River system. The Mason Valley groundwater surface water model (MVGSM) couples the river/drain network with agricultural demand areas and the groundwater system using MODFLOW, MODFLOW’s streamflow routing package, as well as a surface water linking algorithm developed for the project. The MVGSM is capable of simulating complex feedback mechanisms between the groundwater and surface water system that is not dependent on linearity among the related variables. The spatial scale captures important hydrologic components while the monthly stress periods allow for seasonal evaluation. A simulation spanning an 11-year record shows the methodology is robust under diverse climatic conditions. The basin-wide modeling approach predicts a river system generally gaining during the summer irrigation period but losing during winter months and extended periods of drought. River losses to the groundwater system approach 25% of the river’s annual budget. Reducing diversions to hydrologic response units will increase river flows exiting the model domain, but also has the potential to increase losses from the river to groundwater storage.     

Groundwater Management in Coastal Areas through Landscape Scale Planning: A Systematic Literature Review

Environmental Management - Groundwater is one of the main resources for social-ecological systems. As part of the total water cycle and deeply connected with land use, groundwater management faces...     

A Conflict-Resolution Model for the Conjunctive Use of Surface and Groundwater Resources that Considers Water-Quality Issues: A Case Study

The conjunctive use of surface and groundwater resources is one alternative for optimal use of available water resources in arid and semiarid regions. The optimization models proposed for conjunctive water allocation are often complicated, nonlinear, and computationally intensive, especially when different stakeholders are involved that have conflicting interests. In this article, a new conflict-resolution methodology developed for the conjunctive use of surface and groundwater resources using Nondominated Sorting Genetic Algorithm II (NSGA-II) and Young Conflict-Resolution Theory (YCRT) is presented. The proposed model is applied to the Tehran aquifer in the Tehran metropolitan area of Iran. Stakeholders in the study area have conflicting interests related to water supply with acceptable quality, pumping costs, groundwater quality, and groundwater table fluctuations. In the proposed methodology, MODFLOW and MT3D groundwater quantity and quality simulation models are linked with the NSGA-II optimization model to develop Pareto fronts among the objectives. The best solutions on the Pareto fronts are then selected using YCRT. The results of the proposed model show the significance of applying an integrated conflict-resolution approach to conjunctive use of surface and groundwater resources in the study area.     

Artificial Groundwater Recharge Zones Mapping Using Remote Sensing and GIS: A Case Study in Indian Punjab

Artificial groundwater recharge plays a vital role in sustainable management of groundwater resources. The present study was carried out to identify the artificial groundwater recharge zones in Bist Doab basin of Indian Punjab using remote sensing and geographical information system (GIS) for augmenting groundwater resources. The study area has been facing severe water scarcity due to intensive agriculture for the past few years. The thematic layers considered in the present study are: geomorphology (2004), geology (2004), land use/land cover (2008), drainage density, slope, soil texture (2000), aquifer transmissivity, and specific yield. Different themes and related features were assigned proper weights based on their relative contribution to groundwater recharge. Normalized weights were computed using the Saaty’s analytic hierarchy process. Thematic layers were integrated in ArcGIS for delineation of artificial groundwater recharge zones. The recharge map thus obtained was divided into four zones (poor, moderate, good, and very good) based on their influence to groundwater recharge. Results indicate that 15, 18, 37, and 30 % of the study area falls under “poor,” “moderate,” “good,” and “very good” groundwater recharge zones, respectively. The highest recharge potential area is located towards western and parts of middle region because of high infiltration rates caused due to the distribution of flood plains, alluvial plain, and agricultural land. The least effective recharge potential is in the eastern and middle parts of the study area due to low infiltration rate. The results of the study can be used to formulate an efficient groundwater management plan for sustainable utilization of limited groundwater resources.     

Participatory Budgeting and Vertical Agriculture: A Thought Experiment in Food System Reform

While researchers have identified numerous problems with food systems, sustainable, just, and workable solutions remain scarce. Recent developments in the food justice literature, however, show which local food movements favor sustainability and justice as problem-solving measures. Yet, some of the ways that these approaches could work in concert are overlooked. Through focusing on how they are compatible, we can understand how such endeavors can improve the conditions for community control and reduce the detrimental effects of agribusiness. In this paper, the author proposes a participatory budgeting project that involves a relatively new process called “vertical agriculture” to alleviate some of the harm that current agricultural practices cause. In turn, we see how such a measure can improve the integrity of municipal governance and reshape the power structures that control food systems.     

一种四电极电导率传感器的研制与实验

采用高温共烧结技术制备将工作电极与激励电极热压并一次共烧成一体的电导敏感芯体,测量范围0~200μS/cm,精度小于±1.5%FS。介绍了该电导传感器的测量原理、电路方案、封装结构及工艺流程。通过对其进行性能实验,验证该传感器具有测量精度高的特定,并考核了传感器的长期稳定性。     

Sustainable Forest Management Preferences of Interest Groups in Three Regions with Different Levels of Industrial Forestry: An Exploratory Attribute-Based Choice Experiment

The challenge of sustainable forest management is to integrate diverse and sometimes conflicting management objectives. In order to achieve this goal, we need a better understanding of the aspects influencing the preferences of diverse groups and how these groups make trade-offs between different attributes of SFM. We compare the SFM preferences of interest groups in regions with different forest use histories based on the reasoning that the condition of the forest reflects the forest use history of the area. The condition of the forest also shapes an individual’s forest values and attitudes. These held values and attitudes are thought to influence SFM preferences. We tested whether the SFM preferences vary amongst the different interest groups within and across regions. We collected data from 252 persons using a choice experiment approach, where participants chose multiple times among different options described by a combination of attributes that are assigned different levels. The novelty of our approach was the use of choice experiments in the assessment of regional preference differences. Given the complexity of inter-regional comparison and the small sample size, this was an exploratory study based on a purposive rather than random sample. Nevertheless, our results suggest that the aggregation of preferences of all individuals within a region does not reveal all information necessary for forest management planning since opposing viewpoints could cancel each other out and lead to an interpretation that does not reflect possibly polarised views. Although based on a small sample size, the preferences of interest groups within a region are generally statistically significantly different from each other; however preferences of interest groups across regions are also significantly different. This illustrates the potential importance of assessing heterogeneity by region and by group.     

人类活动对城市地下水影响的探讨

通过对城市地下水包气带特征、地下水的排泄和补给特征、雨水排泄特征的系统分析，认为由于城市地下水系统受自然条件和人为因素双重作用的控制使之表现出与自然状态下完全不同的特征：由于地表的硬化，城市包气带由三层结构变为四层结构，即地表硬化层、土壤水带、中间带和毛细水带；城市地区的人文历史沉积也会对包气带造成影响；雨水主要通过城市的排水系统排泄。地下水主要通过人工开采排泄，都表现出集中排泄的特点。文中还对酸沉降对城市地区地下水水质和包气带性质可能受到的影响进行了初步的分析。