Missing Markets and Redundant Reservoirs

This paper uses a two-sector, two-period,spatial model of groundwater usage withstochastic surface water supply to illustratethe potential for the suboptimal management ofthe timing of groundwater uses. A ``timeprofile externality' is said to exist when thetiming of groundwater extraction by one set ofusers impacts on the time profile of wateravailability to another set of users. Theexistence of the time of use externalitydepends on the presence of importantdifferences in the preferences between thecontrol and non-control sectors. It alsodepends on the absence of the markets thatwould internalise these differences. Oneimportant implication of the existence of suchexternalities is that they can inducesub-optimal insurance investments in the formof water storage capital, i.e., unnecessarysurface water reservoirs.     

Theory and practice of value management and its innovation for natural resources from the perspective of sustainable development

The supreme obstacle for sustainable development of natural resources is the scarecity, bottleneck. So how to promote the sustainable utilizing and increase the using efficiency of natural resources is worth studying. This paper suggests that we should improve the model and means of evaluating method and value management based on th~ theory of natural resource compensation. This paper discusses the User Cost Method based on the microeeonomicaspect which can change the evaluating method for natural resources. From the perspective of value managemen model, we should use the User Cost Method to realize the linkage and integration of micro and macro eompensation for natural resources. Based on the evaluating and aecounting idea User Cost Method, this paper presents a theo. retical framework to harmonize and link micro and macro compensation for natural resources. At present, we should seek the new approach and method to manage natural resources, so can we realize the capitalization managemen focusing on the vahte management for natural resources.     

Prevention versus Treatment under Precautionary Regulation: A Case Study of Groundwater Contamination under Uncertainty

Policy discussions on agricultural pollution problems characterize prevention as more cost effective and precautionary than ex post treatment. We derive conditions under which treatment alone is more cost effective in situations involving multiple sources of emissions, multiple sites affected, and a commonly used precautionary approach to uncertainty. We also show that a greater degree of precaution can result in less reliance on prevention. An empirical case study indicates that treatment alone is the most cost-effective means of dealing with nitrate in most Maryland community water system wells. The use of leaching prevention measures is restricted to the most intensive poultry producing areas. The incremental cost of precaution is substantial.     

What Can Be Learned from DuPont and the Freon Ban: A Case Study

Between 1974 and 1988, executives of DuPont, the world's largest producer of CFCs, were confronted with emerging evidence that CFCs were destroying the stratospheric ozone layer. The difficulty that executives face in such cases is that scientific knowledge develops over time and does not necessarily proceed in a straight line toward true conclusions. At the beginning of a new field of research, there is much uncertainty and disagreement among the experts. The solution of the ozone problem required a remarkable cooperation among science, business, and international governments. After looking at the role of DuPont executives in this drama, and the difficulties facing any executive dealing with uncertain science, the paper turns to an evaluation of the field of Business Ethics to see what light it might throw on this and analogous problems. Finally, the paper offers specific suggestions in terms of principles in dealing with uncertain science, and concludes that the course of action that DuPont followed, including some mistakes, can serve as a model for analogous crises.     

Joint Quantity/Quality Management of Groundwater

Economic literature on groundwater managementhas traditionally been split into two areas: there are papers that evaluate different schemes of dynamicaquifer management, considering that pumping costs vary with stock but ignoring water quality. On the other hand, there are papers that considercontamination problems caused by specificpollutants. This paper presents two alternative models for joint quantity-quality management, and it shows that existing models are in fact special cases of these. The framework isdynamic and considers both the stock of waterquantity and a stock measure of water quality. Optimal taxes are derived, and shown to be different from those in existing quantity-only or quality-only models. Implementationproblems are briefly discussed.     

Rural electrification and groundwater pumps in India: Evidence from the 1982–1999 period

India's groundwater extraction is heavily dependent on diesel pumps, and one reason is the lack of reliable power supply. The widespread use of diesel pumps is an economic problem due to the inefficiency and high cost of said pumps. Could rural electrification improve the situation? We estimate the relationship between village electrification and the counts of electric and diesel pumps in India, 1982–1999. We find that, in addition to increasing the number of electric pumps, rural electrification also greatly increases the number of diesel pumps. While initially surprising, these results make sense in an environment characterized by frequent power outages and constant quality problems. If rural electrification increases the number of electric pumps and promotes irrigated agriculture, the demand for diesel pumps also grows because many farmers need a reliable pump that does not depend on electricity. Without improvements in the supply of electricity through rational power sector reforms, India cannot stop the spread of diesel pumps through rural electrification. For energy and development economists, the results are novel because previous econometric work has largely focused on industrial uses of power.     

Climate change,fossil fuel prices and depletion: The rationale for a falling export tax

This paper examines how world prices affect depletion of exhaustible fossil fuels for export and the role of an export revenue tax in curbing depletion. Both effects are studied for a small open economy affected by climate change. We find that setting an export revenue tax rate to fall over time at the marginal social cost of depletion due to lower productivity from climate change encourages a resource exporter to leave an optimal stock in the ground – unextracted and unburnable. Growing prices during the past decade similarly curb depletion. Falling prices bring forward extraction. Because production is independent of consumption, the marginal social cost is independent of utility parameters which are difficult to estimate. Slowing fossil fuel extraction and the effective export of emissions is a contemporary challenge for climate policy. Our findings identify both why an export revenue tax should decline over time and an estimable target rate of decline to help meet this challenge amid changing world prices.     

Measuring Production and Irrigation Efficiencies of Rice Farms: Evidence from the Punjab Province,Pakistan

We employ a non‐parametric approach, data envelopment analysis, to estimate the technical and irrigation efficiency of rice farms in the Punjab Province of Pakistan. We use a cross‐sectional dataset of 80 rice growers, including 45 tube‐well owners and 35 water buyers. Mean technical efficiency scores show that tube‐well owners and water buyers are operating at fairly high efficiency levels, indicating that access to technology is not a major constraint. However, irrigation inefficiency is pronounced, with water buyers being more inefficient than tube‐well owners. A bootstrap truncated regression is used to investigate the determinants of technical and irrigation efficiency. We suggest that groundwater management policies should be designed to address efficiency enhancing factors such as knowledge of crop water consumption requirement, better credit opportunities, outreach extension services and training programs.     

钙镁离子及重碳酸盐对零价铁还原对氯硝基苯的影响

通过间歇式实验,考察了地下水中常见硬度离子Ca2＋、Mg2＋及HCO3-的独立作用和联合作用对零价铁还原对氯硝基苯的影响。实验结果表明,Ca2＋、Mg2＋对零价铁还原对氯硝基苯反应的促进作用不明显。HCO3-浓度为0～100mg/L时可显著提高零价铁还原对氯硝基苯的速率,反应2 h后对氯硝基苯转化率由44.1%升至84.8%;当HCO 3-浓度大于100 mg/L时,促进作用会由于碳酸铁盐类物质的产生而下降。当Ca2＋或Mg2＋与HCO3-共存时,会产生碳酸钙或碳酸镁之类的沉淀物,占据还原位点,不利于反应的进行。当采用零价铁修复地下水氯硝基苯化合物污染时,应考虑地下水硬度的影响。     

地下水中硝酸盐污染及修复技术

文章介绍了地下水中硝酸盐污染来源,并阐述了地下水中硝酸盐污染的三种修复技术,即物理化学修复技术、化学修复技术和生物修复技术,同时还回顾了利用这些修复技术治理硝酸盐引发的地下水污染方面的研究成果,最后提出了防治地下水中硝酸盐污染的建议。