Exposure and resilience of China’s cities to floods and droughts: a double-edged sword

Abstract

China’s rapid urbanization in areas prone to flood or drought events can be seen as a double-edged sword. Urbanization enlarges the population exposed to these hazards, but the resulting socio-economic development also helps build resilience. This article quantifies flood occurrence, drought severity, and related resilience in 81 cities in Mainland China. The extent of flood exposure was notable, both in absolute terms as well as in relation to the drought-prone urban population. China needs to integrate urban flood/drought policy making with sustainable urbanization policy making to best contribute to minimizing flood and drought risks in its cities.     

基于概率性Budyko方程的我国可利用水资源量脆弱性评估

利用概率性Budyko方程定量评估我国可利用水资源量空间分布情状及其相应的不确定性,识别我国可利用水资源量高脆弱性地区。结果表明,降水是影响可利用水资源量脆弱性的主导因素,并且较为干旱的区域具有较低不确定性;我国东北地区、西北地区、华北地区以及华东地区北部这一带状地区的可利用水资源量最易受到降水变化的影响,并且在降水减少量不同(分别减少5%、10%、15%)的情况下这种现象依然明显,可见这些地区对降水变化呈现高度的脆弱性。     

全球气候变化对中国淡水资源及其脆弱性影响研究综述

由温室效应引发的全球气候变化问题已成为世界各国政府和专家、学者关心的焦点问题。在分析近几十年来我国淡水资源变化特点及气候条件波动或变化对径流现实影响的基础上,较系统地总结了近10年我国在气候变化影响的某些方面的研究成果,主要集中在我国淡水资源对气候变化的敏感性和水资源在气候变化情景下的脆弱性两个方面的问题。     

气候变化与中国水资源可持续利用

全球变暖是目前最重要的环境问题之一.根据目前的相关研究成果,介绍了中国气候变化及其影响的事实,论述了中国水资源特点及目前存在的问题,分析了气候变化对中国典型流域河川径流量变化的贡献、未来气候变化对水资源的可能影响、以及水资源系统对气候变化的敏感性和脆弱性;结合中国的实际情况,初步提出了水资源管理中应对气候变化的基本适应对策.     

The economic impact of water tax charges in China: a static computable general equilibrium analysis

This paper presents a static computable general equilibrium model of the Chinese economy with water as an explicit factor of production. This model is used to assess the broad economic impact of a policy based on water demand management, using water tax charges as a policy-setting tool. It suggests that imposing water taxes can redistribute sectoral water use and lead to shifts in production, consumption, value added, and trade patterns. Another important finding is that water taxes imposed on the agricultural sector drive most of the effects.     

Strategies for coping with inadequate domestic water supply in Abuja,Nigeria

This article explores household strategies for coping with inadequate domestic water supply in Abuja, and the factors that affect strategy choice. In-depth interviews found that water storage (90%), bottled and sachet water (82%), water vendors (78%) and fetching water from neighbours (60%) were prefered for coping with inadequate water supply over water conservation and recycling (38%), boreholes (23%), home water treatment (15%), and surface water (10%). The necessity of water, costs of coping strategies, housing characteristics, socio-economic factors and planning regulations influenced household choice of strategies.     

Management Implications to Water Resources Constraint Force on Socio-economic System in Rapid Urbanization: A Case Study of the Hexi Corridor,NW China

As water has become the shortest resources in arid, semi-arid and rapid urbanization areas when the water resources utilization has approached or exceeded its threshold, water resources system slows down the socio-economic growth rate and destroys the projected targets to eradicate poverty and realize sustainable development. We put forward the concept of Water Resources Constraint Force (WRCF) and constructed a conceptual framework on it. Conceptual models on the interactions and feedbacks between water resources and socio-economic systems in water scarce regions or river basins indicate that, if the socio-economic system always aims at sustainable development, WRCF will vary with a normal distribution curve. Rational water resources management plays an important role on this optimistic variation law. Specifically, Water Demand Management (WDM) and Integrated Water Resources Management (IWRM) are considered as an important perspective and approach to alleviate WRCF. A case study in the Hexi Corridor of NW China indicates that, water resources management has great impact on WRCF both in Zhangye and Wuwei Region, and also the river basins where they are located. The drastic transformation of water resources management pattern and the experimental project – Building Water-saving Society in Zhangye Region alleviated the WRCF to some extent. However, from a water resources management view, WRCF in Zhangye Region still belongs to the severe constraint type. It will soon step into the very severe constraint type. In order to shorten the periods from the very severe constraint type finally to the slight constraint type, WDM and IWRM in the Hei River Basin should be improved as soon as possible. However, in the Shiyang River Basin, WRCF belongs to the very severe constraint type at present due to poor water resources management in the past. Though the socio-economic system adapted itself and alleviated the WRCF to some extent, the Shiyang River Basin had to transform the water supply management pattern to WDM, and seek IWRM in recent years. It is concluded that WDM and IWRM is a natural selection to alleviate the WRCF on the socio-economic system and realize sustainable development.     

西南岩溶石山地区水窖水质状况及保护措施

以云南省木美地下河流域为例,就西南岩溶区水窖的水质状况进行分析,结果表明水窖的水质状况尚为良好。由于水窖建材及水源类型等的不同,导致水窖水质的差异。水窖的污染类型有四类:颜色、肉眼可见物异常;超长时间放置导致生物性污染;pH值呈碱性;生活垃圾和污水引起HCO-3,Ca2+,Na+,Cl-等离子超标。建议加大力度,加强水源地的保护,改善水窖的水质。     

Influence of disaster risk,exposure and water quality on vulnerability of surface water resources under a changing climate in the Haihe River basin

A function model was used to quantify the vulnerability of the Haihe River basin on the basis of sensitivity, adaptability of the water resources system, exposure and drought disaster risk. Surface water resources vulnerability was assessed for a benchmark year (2000) using the function and indicator models and for modelled future climate scenarios using only the function assessment model. In the results, surface water resources vulnerability was greater when exposure, disaster risk and water quality factors were considered. Both models gave the result that vulnerability of water resources in study area was high; all the regions were rated ‘highly’, ‘strongly’, or ‘extremely’ fragile.     

Agricultural land investments and water management in the Office du Niger,Mali: options for improved water pricing

Large-scale agricultural land investments in Africa are often considered solely from the land perspective. Yet land, water and other natural resources are closely interlinked in agricultural production and in sustaining rural livelihoods. Such investments involving irrigation will potentially have implications for water availability and utilization by other users, making it imperative to regard water as an economic rather than a free good. Focusing on a vast irrigable area in Mali with recent large-scale investments, a bio-economic model was used to demonstrate that an improved water valuation system is needed to balance different water users’ needs while ensuring adequate environmental flow.     

Rehabilitating rivers and enhancing ecosystem services in a water-scarcity context: the Yarqon River

After the creation of the state of Israel in 1948, the increase in urban and agricultural water demand and the increased flow of poorly treated sewage had a severe impact in one of the most ecologically important rivers in Israel, the Yarqon. The attempt to reverse this situation began with the creation of the Yarqon River Authority in 1988. In the last 20 years, the authority has implemented or collaborated in several projects that have significantly contributed to enhancing the provision of ecological services. This article aims to analyze the case of the pollution and subsequent rehabilitation of aquatic ecosystem services in the Israeli water-scarcity context.     

Water conservation under scarcity conditions: testing the long-run effectiveness of a water conservation awareness campaign in Jordan

This study measures the long-run effect of the Abu Tawfeer media campaign in Jordan. Based on a representative sample (N = 367) conducted five years after the end of the campaign, a multivariate instrumental variable regression analysis shows that the campaign only marginally changed people’s water conservation awareness and behaviour. The rigorous methodological approach allows disentangling the distinct channels through which the effect of the conservation campaign was transmitted. Moreover, this is one of the first studies that comprehensively examines the role of awareness in determining water conservation behaviour.     

A perfect storm: the causes and consequences of severe water scarcity,institutional breakdown and conflict in Yemen

Yemen faces a dire water availability crisis, with groundwater being extracted at four times the rate of natural recharge and the capital, Sana’a, at risk of running out of water altogether. Yemen’s capacity to adapt to water scarcity has been undermined by misrule, weak institutions and patronage-driven politics that have eroded traditional tribal mechanisms of water governance and conflict management without leaving a viable alternative in their place. Using material gleaned from interviews with water specialists, this article investigates the forces impeding water reform and the mechanisms mediating the relationship between water scarcity, institutional dysfunction and violent conflict in Yemen.     

云南省活动断裂对基岩裂隙水的控制作用研究

为了解云南地区活动断裂对地下水分布的影响,根据2010年云南省抗旱工程的635个基岩抽水井资料和1∶400万云南地区活动断裂数据库,采用统计方法分析该地区活动断裂及河流对抽水井分布及富水程度的控制作用。研究发现:抽水井主要分布在走向为NNE-SSW和NNW-SSE的断裂带上,且距离断裂带越近,抽水钻孔内裂隙越发育,单位涌水量越大。此外,距离抽水井最近的河流走向亦以NNE-SSW和NNW-SSE为主,与断裂的主要走向一致。抽水井距离河流越近,其单位涌水量越大,进一步说明断裂对基岩裂隙水的控制作用。     

Regulation leads to increases in riparian vegetation,but not direct allochthonous inputs,along the Colorado River in Grand Canyon,Arizona

Dams and associated river regulation have led to the expansion of riparian vegetation, especially nonnative species, along downstream ecosystems. Nonnative saltcedar is one of the dominant riparian plants along virtually every major river system in the arid western United States, but allochthonous inputs have never been quantified along a segment of a large river that is dominated by saltcedar. We developed a novel method for estimating direct allochthonous inputs along the 387 km‐long reach of the Colorado River downstream of Glen Canyon Dam that utilized a GIS vegetation map developed from aerial photographs, empirical and literature‐derived litter production data for the dominant vegetation types, and virtual shorelines of annual peak discharge (566 m³ s^?1 stage elevation). Using this method, we estimate that direct allochthonous inputs from riparian vegetation for the entire reach studied total 186 metric tons year^?1, which represents mean inputs of 470 gAFDM m^?1 year^?1 of shoreline or 5.17 gAFDM m^?2 year^?1 of river surface. These values are comparable to allochthonous inputs for other large rivers and systems that also have sparse riparian vegetation. Nonnative saltcedar represents a significant component of annual allochthonous inputs (36% of total direct inputs) in the Colorado River. We also estimated direct allochthonous inputs for 46.8 km of the Colorado River prior to closure of Glen Canyon Dam using a vegetation map that was developed from historical photographs. Regulation has led to significant increases in riparian vegetation (270–319% increase in cover, depending on stage elevation), but annual allochthonous inputs appear unaffected by regulation because of the lower flood peaks on the post‐dam river. Published in 2010 by John Wiley & Sons, Ltd.     

From an open-access to a state-controlled resource: the case of groundwater in the Kathmandu Valley,Nepal

Groundwater is no longer an open-access resource in Kathmandu. Perceptions of groundwater are changing from an “infinite” to a “finite” resource and the role of the government from supply developer to caretaker of the resource. In this context, this paper aims to unfold how perceptions of groundwater in Kathmandu Valley, Nepal, are changing from an open-access resource to an overexploited, depleted, degraded, vulnerable and state-controlled resource. In the process, it produces an aggregated picture of resource availability, development dynamics, impacts and responses in the area; suggests some “soft-path” approaches for groundwater management; and discusses implications of the experience for other areas.     

中国水质管理的现状、问题及挑战

简述水质管理的基本内涵,分析中国水环境质量现状及流域未来的水污染发展趋势。指出了现行水质管理体制及政策手段存在的问题和不足,并针对这些问题,提出了加强水质管理、完善相关体制政策的若干建议。     

Bilateral virtual water trade in agricultural products: a case study of Germany and China

Most studies in the field of virtual water trade concentrate either on the global, national or sub-national level, or on the water footprint of individual products. This article assesses the virtual water trade in agricultural products between Germany and China during the period 2008–2010. Germany exported 192 million m³ of virtual water to China and imported 801 million m³ from China. Through the bilateral trade, Germany saved 69.8 million m³ water, while China had a net water loss of 469.4 million m³. Thus, the global water loss amounts to 399.6 million m³.     

Approximate bottom contribution to remote sensing reflectance in Taihu Lake, China

Remote sensing is a fundamental tool for the analysis of spatial and temporal trends in lake ecosystems. A major challenge in using these approaches is determining the possible influence of reflectance from submerged vegetation or the lake bottom. In the present study, we examine the water leaving radiance measured in a large number of sites in Taihu Lake, a large shallow lake in southeast China. Due to the high concentrations of suspended sediment and phytoplankton biomass, a majority of the lake can be considered optically deep (i.e. bottom reflectance could be ignored). However, optically shallow waters were present in the shallow bays on the eastern side of the lake. In these areas, submerged vegetation was present. To explore the contribution of the lake bottom and submerged vegetation on remotely sensed reflectance, we compared two modeling approaches (Hydrolight and the LEE). The results show that differences in optical and physical characteristics of the lake bottom strongly influence the spectral characteristics of the measured reflectance. The resulting impact on the estimate of chlorophyll-a concentrations was tested using datasets with and without sites where bottom effects may occur. A significant improvement in the predictive capacity of the reflectance based estimated of phytoplankton biomass was made when areas with bottom influences were removed from the calibration procedure.     

Rhetoric and reality in the allocation of water to the environment: a case study of the Goulburn River,Victoria, Australia

In the Goulburn River, located in Victoria (Australia), dams and diversions for irrigation have modified streamflows and water temperature, and contributed to environmental degradation that includes declining native fish populations. With the passage of a new Water Act in 1989, the Victorian Government proposed to address environmental and water allocation issues through the development of tradeable water entitlements. Initially, these had a strong environmental focus and were to be allocated within an adaptive management framework that involved monitoring and evaluation to refine the total allowable diversion to sustainable levels. The actual specification of tradeable water entitlements for the Goulburn River, undertaken in 1995, differed substantially from those early proposals. Entitlements were largely based on historical use with limited and ineffective allocation of water to the environment because water temperature was not considered. A water market has been established but market failure is likely to result in an under‐allocation of water to the environment. Access to the market is restricted except to irrigation authorities and water users, and transaction costs and uncertainties in environmental requirements reinforce the status quo in water allocation which is dominated by production values. Copyright © 2002 John Wiley & Sons, Ltd.