THE EFFECT OF PRICE ON LONG RUN WATER SUPPLY BENEFITS AND COSTS1

ABSTRACT The long-term effects of presently used and alternatively proposed water pricing policies were studied using some tools of operations research and economics. A discrete deterministic dynamic programming model was structured and operated to determine the optimal water supply capacity expansion paths for a hypothetical residential community with a given water pricing policy. The objective of the model was the maximization of future discounted consumers'surpluses plus producer's revenues net of the long-run cost of supply. State variables were the size of system capacity in MGD and stage variables were the times of feasible capacity increase in years. Demand curves, population sizes, and growth rates for various economic sectors of the community were assumed known, as well as short-run production and capital construction costs. Several policies, including constant unit rates, decreasing or increasing block rates and summer differential rates were tested. It was concluded that price plays a major role in the short-run allocation and long-run planning and conservation of water supplies. Conservational pricing policies were advocated as means of lowering the long-run cost of water, using the water price-demand function as a planning tool. Further research in these areas was recommended.     

ECONOMIC GROWTH THROUGH WATER RESOURCE DEVELOPMENT: INDIA1

ABSTRACT India's multidimensional water development programs have contributed significantly to the promotion of the country's economic growth. Rapid growth of irrigation has substantially increased agricultural production. Hydro power generation has doubled during the last two decades, and this has accelerated industrialization and extended rural electrification. Minor irrigation has taken on a new importance in the Fourth Five Year Plan, signifying a departure from the earlier Plans. “Green Revolution” owes a large measure of its success to the availability of assured water supplies. Water development projects have also generated tremendous employment opportunities. Despite its pronounced impact on the economy, India's water planning strategy has some glaring weaknesses: the failure to incorporate “indirect benefits” in cost-benefit calculations; the under-utilization of water potential; and, the progressive increase in the cost of irrigating an acre of land. The prevailing institutional structure in India constitutes a major deterrent to the diffusion of the benefits of water development. There are stubborn psychological factors which render the adoption of innovative irrigation practices difficult. There is thus an overwhelming need to revamp India's institutional framework. On balance, however, water development in India has made its impact felt on India's myriads of villages. And from the arid “dust bowls” of India new life has emerged.     

沈阳市大学绿化建设与污水再生资源化利用

以辽宁大学等新校园建设污水回用工程为例,阐述了水资源综合利用等问题,对中水回用技术进行了详细介绍,并分析了中水回用的环境效益及经济效益。     

农村城镇化规划及环境效益

实现新农村规划,彻底改变以前农村分散庭院式居住的落后面貌,实现农村生活城镇化、现代化、居住楼房小区化,饮用经过处理达标的饮用水,炊灶利用现代化的清洁能源。楼房有利于实行集中供热取暖,改变过去落后的能源使用方式,可节省大量能源,减少碳排放量,有利于环境保护,具有明显的环境效益,建立农村美好的幸福家园。     

稻田养鱼的生态防灾机制与效益分析—以湖南为例

以湖南为例从分散蓄水与扩容蓄水、即时蓄水与重复蓄水、分级截流与设阻截流等角度,分析了稻田养鱼的生态防灾机制,得出湖南宜鱼稻田87.0万hm^2,以蓄水30cm计算可蓄存107.9亿m^3。通过重复蓄水、设阻蓄水,接纳多次降雨洪水,调节水分时空分布,创造减灾避灾的人工生态防灾系统,形成多物种共生共存的农田湿地生态系统,提高农田生态经济效益。     

校园雨水资源化利用的效益分析及利用措施

学校人口密集,用水量大,缺水问题严重,利用雨水资源显得非常重要。在提出校园雨水资源化利用概念的基础上,对某一校园雨水资源化利用的经济效益、环境效益和社会效益做了分析。结果显示,校园雨水资源化利用效益显著,对实现区域水资源可持续利用起着非常重要的作用。同时,对中国校园雨水利用的有利条件以及利用的可行性做了分析研究,并基于此,提出了校园雨水资源化利用的途径和措施。旨在为校园雨水资源化利用的推广提供理论基础。     

2013~2020年甘肃省PM2.5健康负担的时空变化趋势及驱动力

为评估大气污染防治行动计划以来,甘肃省PM_2.5相关健康影响的时空变化趋势及其驱动因素,应用最新的全球暴露死亡模型（GEMM）估算了2013~2020年甘肃省归因于PM_2.5的健康负担,并通过因素分解法进一步探讨了PM_2.5归因死亡长期变化的主要原因. 结果表明,2013~2020年,甘肃省人口加权PM_2.5浓度下降了34.57%,暴露于PM_2.5年均浓度超过35 μg·m^-3的人口比例从72.89%大幅下降至11.61%. 研究期间,甘肃省PM_2.5归因死亡人数从12 826（95%CI：7 840~17 408）人下降至9 814（95%CI：6 407~13 036）人,下降了23.48%;其中,缺血性心脏病的归因死亡人数有所增加（12.11%）,而中风、慢性阻塞性肺病、肺癌和下呼吸道感染的归因死亡人数呈下降趋势;60岁及以上人群的归因死亡人数占80%以上;中东部地区的PM_2.5归因死亡人数显著高于河西地区,且大部分地区呈下降趋势;人口规模、年龄结构、基线死亡率和PM_2.5浓度在归因死亡人数变化中的贡献分别为-1.26%、16.16%、 -9.84%和-28.55%,人口老龄化和PM_2.5浓度降低是PM_2.5归因死亡增加和减少的主要因素. 甘肃省积极的清洁空气政策减轻了PM_2.5污染造成的健康负担,但在人口老龄化加剧的趋势下,未来需要大幅降低PM_2.5浓度才能避免更多的归因死亡.     

Dynamic female preference for multiple signals in <Emphasis Type="Italic">Rhinogobius brunneus</Emphasis>

Many species base their choice of mates on multiple signals which provide them with different kinds of information. Choosers may assess the signals together to evaluate the overall quality of potential mates, but individuals often pay attention to different signals in different contexts. In Rhinogobius brunneus, a fish displaying exclusive male parental care, females generally prefer males showing larger first dorsal fins (FDF) and more active courtship displays as mates. Females choosing a mate usually initially assess the FDF and later utilize courtship for the final decision. In our experiments, females with different hunger states used different signals when selecting mates. Females in both hunger states preferred males with larger FDF in the first stage. In the second stage, well-fed females showed highly repeatable choice, whereas poorly fed females responded only to variation in the courtship activity of males. The males preferred by poorly fed females exhibited significantly higher offspring survival than nonpreferred males. Under conditions of food shortage, males allocate more energy to future reproduction at the expense of the present brood, and females may prioritize signals predictive of offspring survivorship over signals reflecting other aspects in male quality to minimize the losses in direct benefits. We conclude that R. brunneus females may employ information from both signals but dynamically adjust their prioritization of each signal to current conditions to ensure the choice that is currently most adaptive.     

Spatiotemporal dynamics in variable population interactions with density-dependent interaction coefficients

In this article, I present a two-patch metapopulation model with locally explicit dynamics to study the effect of spatial heterogeneity and dispersal upon population interactions with variable or conditional outcomes. These are interactions that may be either detrimental or beneficial for each species depending on the balance of the density-dependent costs and benefits involved. The local dynamics respond to density-dependent α-interaction functions that may change sign, thus yielding a diversity of possible local outcomes for the association in terms of type of interaction and in the number of stable solutions. The spatiotemporal model predicts that the fragmentation of space and dispersal between patches may cause further variation in these outcomes. First, the demographic performance of a species in the association is enhanced if migrations cause a proportional increase of individuals of its own species; being so, a victim may become a mutualist or an exploiter, an excluded species may invade, and a good competitor may overcome its own carrying capacity: the ‘enhancement effect of dispersal’; a sort of rescue effect in source-sink dynamics. The underlying mechanisms involve an interplay between density-dependent effects of dispersal per se and the relative local and global average α-interaction functions, which involve costs and benefits at both the local and regional level that may either counteract or reinforce each other; thus, localities and/or populations may change dynamically their sink or source role in the spatial dynamics. A significant insight arises herewith: in the context of variable or conditional interactions the concept of the role of a species does not make strict sense; it becomes a spatiotemporal dynamic quality. Second, regardless of which species disperses, bifurcation of equilibria may occur in those patches that receive the migrating individuals, and annihilation of equilibria in those from where migration leaves; thus, the number of equilibria increases or decreases accordingly.     

综合考虑减排效益的污染物总量分配方法研究

如何在目标总量控制和容量总量控制间找到契合点,使总量控制既体现环境改善需求,又能促进环保基础设施建设和经济调控目标的实现成为当前的研究重点。基于目标总量控制,探索一种综合考虑减排效益的污染物总量分配方法,构建了以人口、GDP、水资源量、水环境容量和环保投资作为评价指标的环境基尼系数最小化模型,并将其应用于内蒙古自治区COD总量的优化分配。结果表明,与初始分配相比,优化分配后的环境基尼系数总和下降了0.85%,优化后的分配方案更公平、合理。在优化分配过程中,各评价指标间互相制约,较好提高了最终分配结果的科学性和可操作性。