北京市中水回用问题浅析

北京市是一个严重缺水的城市,水资源短缺已成为制约北京市社会经济发展的主要因素。北京市已敲响了水危机的警钟,为了缓解缺水现状,中水回用被提上日程。本文从北京市资源短缺、经济发展和环境改善三个方面论述了北京中水回用的必要性,并对中水回用过程中存在的问题进行分析,指出了北京市政府必须解决的中水回用中存在的问题,并提出了多种解决方案。     

社会资本视角下农民用水户满意度研究——基于陕西省宝鸡峡灌区农民用水户的调查

以社会资本为研究视角,对社会资本维度进行划分,并运用有序Logistic模型,基于陕西省宝鸡峡灌区农民用水户的调查,研究农民用水户对农民用水户协会的满意度及影响因素。研究结果表明,结构维度和认知维度社会资本是影响用水户对协会满意度的重要因素,家庭收入水平、农业收入占家庭收入比重、渠系完好率、协会专业化程度以及用水户参与积极性对用水户满意度有显著影响;关系维度社会资本、用水户性别、年龄、文化程度对用水户满意度没有显著影响。这表明农民用水户协会主要承担着灌溉管理和农业发展的职能,而其承担的社会功能相对较弱。     

Areal differentiation of virtual water for agricultural products and its effect on regional agricultural structure adjustment in China： 1995-2007

With a vast territory, the space-time distribution of water resources is uneven in China. There is a great dif ference in natural conditions and farmland management of agricuttural production in different regions. The areal differentiation of agricultural products virtual water is obvious. Comparison with the agricultural products virtual water from 1995 to 2007 in China shows an increase in the first ten vears and a little decrease in recent years. There has been a tendency of increase all the time in Northeast and Northwest. but a decrease after an increase firstly in other regions. The virtual water offood crops is the maximum which accounts for more than 70% in China. and that of vegetables is in a fast growth. The proportion of agricultural products virtual water to the total water resources in each region has a large difference, showing the imbalance of agricultural water in different regions, which accounts for 50%-90% in Northeast, and 125%-185% in North China. Under the guidance of virtual water strategy, based on the differences of resource endowment, each region should adjust agricultural structure, decide production by water, and select water suitable crops. In water-rich region, agricultural produets of high water consumption should be planted appropriately, which will make full use of the abundant local water resources. In water-shortage region the crop production of high water consumption and low efficiency should be depressed, and that of low water consumption and high efficiency should be supported and increased. It will achieve reasonable disposition of water resources, promote ecological restoration and environmental protection, as welt as ensure food security.     

Determinants of residential water demand in Germany

We econometrically analyze the impact of several economic, environmental and social determinants for the per capita demand for water in about 600 water supply areas in Germany. Besides prices, income and household size, we consider the effects of population age, the share of wells, housing patterns, precipitation and temperature. We also explore why current per capita residential water consumption in the new federal states is about 30% lower than in the old federal states. Since average cost pricing may cause an endogeneity problem, we apply instrumental-variable procedures in addition to single equation ordinary least squares, but find no evidence that prices are endogenous. Our estimation results suggest that the price elasticity of water demand in Germany is around − 0.24. The income elasticity is positive, decreases with higher income levels and is at least three times higher in the new federal states than in the old federal states. Current differences in prices and income levels explain about one third of the gap in residential water use between the two regions. Household size and the share of wells have a negative impact on per capita water demand, and water use increases with age. Finally, the findings provide some evidence that rainfall patterns rather than total rainfall affect water consumption, while temperature appears to have no impact at all. All outcomes are robust to a log-log and two types of semi-log specifications for the water demand function.     

加强我国城市供水价格机制改革的探讨

随着国民经济的持续快速发展和城市化进程的加快,我国已经有相当部分城市出现了水资源短缺的 状况,城市缺水范围不断扩大,缺水程度日趋严重,水质日益恶化,许多沿江、沿河城市不断受到洪水威 胁,水短缺、水污染、水安全等已经成为制约国民和社会发展的重要因素,对２１世纪我国的环境与发展造成 了巨大的潜在压力。特别是水资源对于将来的地区和平、全球粮食安全、城市经济的增长、工业的选址、能 源化工基地的建设、城市规划的实施,以及西部大开发的推进,都产生着越来越深刻的影响。可是,由于我 国目前的城市供水价格机制不尽健全,在一定程度上不利于加强水资源使用的宏观调控,降低了水资源的利 用效率,成为国民经济发展的制约和瓶颈。因此,探讨科学的城市供水价格机制,具有重要现实意义。     

水生态系统服务供需视角下的水网乡村 适应性规划策略——以吴江张鸭荡片区为例

苏南乡村地区一直是中国乡村建设的先行区域,特殊的纵横交错的水网结构构成了一个错综复杂的系统,呈现出其他地区不具有的复杂性和生态特殊性。随着城镇的扩张,乡村的发展建设使其水网空间的平衡发展面临极大的挑战。传统单一静态的规划方法逐渐显示出无法适应经济、社会等发展要求的缺陷。苏南乡村地区以水为核心,从水生态系统服务供需关系的视角下探究水网乡村的适应性规划策略更加适应当前的乡村现状和需求。以传统水网乡村空间形态转译为基础,建立水生态系统供需服务评估体系,在评估水生态系统服务供需能力的基础上,分析供需分异模式及供需矛盾。从构建乡村水域空间生态格局、乡村水域空间功能分区规划,以及乡村水域空间多情景预判3个方面,提出苏南水网乡村的适应性规划策略,并为水网乡村的生态实践提出新思路。     

中国农畜产品虚拟水区域分布空间差异

虚拟水是当今水科学的研究热点,被认为是解决粮食与水资源安全的重要策略.在测算中国各地区农畜产品虚拟水总量的基础上,利用伪基尼系数对虚拟水区域差异的成因进行凶子分解,表明畜产品中的禽蛋、猪肉、牛肉和农产品中稻谷、小麦、玉米成为影响中国虚拟水空间差异的丰要因子.同时,借助锡尔指数对1996-2006年的中国八大区域虚拟水-耕地资源空间差异进行分解,结果表明:虚拟水-耕地资源区域总体差异在不断缩小,影响区域总体差异形成的主导因素是八大区域问的差异.文章旨在揭示地均农畜产品虚拟水区域差异来源以及差异背后体现的农业集约化空间分异特征规律,为制定不同区域类型的农业发展决策提供相应的理论参考.     

南水北调中线工程水源地的生态安全与对策研究

南水北调中线工程是我国进行水资源优化调配,解决北方,尤其是京、津、冀地区资源性缺水的21世纪重大战略工程。丹江口水库汉江上游地区为水源地.由于其水土流失和局部水体污染严重,自然灾害频繁,中线工程的建设使得水源地生态环境的综合治理更为紧迫,因此维护水源地生态安全的重点在于水源地的综合治理,其关键是加大水源地生态建设的投入.并完善南水北调中线工程管理体制,加强立法体系的建设,抓紧生态环境综合治理和建设重点,尽快建立科学合理的生态补偿机制和绿色GDP核算体系.加大水源地生态安全相关课题的研究等政策建议。     

宁波水资源利用效率现状及趋势分析

对水资源利用效率问题的研究,有助于发现和改善水资源开发利用中存在的不合理、低效率等问题,促进水资源利用效率的提高。本文运用回归分析和H-P滤波法对1997—2006年宁波市用水效率进行分析,发现全市用水效率总体上呈现逐渐上升的趋势,未来不论是生产用水,还是生活用水,都存在较大的节水空间。     

低水分活度的预包装食品中菌落总数复查的研究

为了探讨食品抽检中菌落总数指标复检的可能性,通过对水活度较低的预包装食品乳粉、营养米粉、燕麦片、膨化食品、蜂蜜进行菌落总数测定,对低水分活度预包装食品菌落总数指标的稳定性进行分析。结果表明,同一批次、同一储存条件的未开封预包装食品在不同保存周期内菌落总数在统计学上无显著差异,本研究结果可为低水分活度预包装菌落总数的复查可行性提供参考依据。