Households＇ Assessment of the Water Quality and Services of Multi-model Urban Water Supply System in the Informal Settlements of Dar es Salaam, Tanzania

In the global south wide range of studies highlight the limitations of the single-modelled public urban water system to meeting the endogenous water preferences of the urban population. Studies also touched on the complementary roles of private water actors to the single-modelled public water supply system in the urban water supply network. Multiple of urban water supply systems （multi-model） co-exist in the urban landscape of global south. However, it is unclear and largely inconclusive on the suitable and satisfactory urban water supply model that meets the water consumption needs of informal settlement dwellers in the global south. This study draws the experiences of households in the informal settlements using a case-study with cross-sectional survey strategy to assess the suitability of the multi-model urban water supply system for sustainable urban water supply in the informal settlements. A total of 292 households were randomly sampled alongside 35 purposively sampled private water actors and public water departments. The data were collected through face to face interviews. Findings show that water supply services of the multi-model water supply system are inevitably suitable for the water consumption needs of informal settlements’s dwellers. The operation of the multi-model water supply system is flexible and able to accommodate the diverse water consumption preferences and choices of the different socio-economic groups in the informal settlements. We observed that multiplicity of urban water supply system increases households’ access to water but does not necessarily improve the quality of water serve in the informal settlements. The paper recommended for the formalisation and adoption of the multi-model urban water supply system to meet the growing demand for improved water supply and services in the informal settlements.

Urban Water Supply Industry Marketization of China in View of Public Water Service and Water Resource Management

Started with the discussions on the value orientation of urban water supply industry marketization,the article points out that the current urban water supply industry marketization reform is inconsistent with the goal of public water service equalization to some extent.The article also analyzes the problems emerged in urban water supply industry marketization reform and various rea-sons in view of efficiency and fairness.An efficiency and fairness oriented management model is built in this article to illustrate how the government should conciliate interests of various communities involved in the process of marketization reform of the urban water supply industry so as to actualize the coordination of efficiency and fairness.At the end,an assumption on urban water price is put forward to help achieve the public water service equalization.

Characteristics of groundwater and urban emergency water sources optimazation in Luoyang,China

The construction of emergency water sources is the material basis for ensuring urban water safety,and it is also an inherent requirement for maintaining social stability and development.The hydrogeological characteristics of groundwater in Luoyang City from the aspects of the division of groundwater aquifer groups,water yield property and groundwater dynamics were described in this paper.Two emergency water sources were selected on basis of comprehensively considering groundwater resources and ecological environmental effects,groundwater quality and exploitation technology,etc.Then it further analysed the aquifer types,water yield properties and groundwater recharge,runoff and discharge conditions of the two emergency water sources,and evaluate the groundwater resources quantity of the water sources.The results are that the shallow underground aquifer in Luoyang City is thick,coarse,and stable in lithology and thickness.The two water sources enjoy good exploitation potential and can be used as backup water sources to supply water in the event of a water source crisis.

Potential contributions to Beijing's water supply from reuse of storm-and greywater

In order to find new approaches to alleviating the water crisis in Beijing which is caused by among others dwindling precipitation and rapid growth of population and manifests in a rapidly declining groundwater table this study explores decentralized stormwater harvesting and greywater reuse at household level as a means to reduce groundwater abstraction and water transfer from other regions.Based on a desktop case study two concepts for combined harvesting and reusing of storm-and greywater are presented.With rough pre-assumptions calculations show that a saving of 67.8%of tap water consumption can be achieved with the upgrading concept compared with 5.9% with the simple downgrading concept.The saving with the upgrading concept equals 0.545 ×109 m3 annual water volume if 20 million Beijing people apply this approach.Despite numerous prerequisites such as water treatment technology space demand energy and cost and public acceptance this paper advocates combining stormwater harvesting and greywater reuse in households with other measures for Beijing’s sustainable water management.

Water Resources and Management under Increasing Urban Demography: A Kenyan Perspective—A Review

The United Nations classifies Kenya as a water-scarce country since it has less than 1000 m3 per capita of renewable freshwater supplies. Numerous factors including global warming, contamination of drinking water, and a lack of investment in water resources have aggravated the water crisis in Kenya. Estimates indicate that only about 56% of its population has access to safe water supply. Like many developing countries, Kenya recognizes the crucial role of water in realizing its development goals. Its economic performance and poverty reduction are critically dependent on clean water availability for agriculture, industrialization, energy production and tourism among others. Similar to most developing countries, Kenya suffers from lack of human, monetary and institutional capabilities to efficiently provide clean and sufficient water to its citizens. The water shortage in the major cities is acute and chronic and has continued to worsen with increasing urbanization, water pollution and encroachment of water catchment areas by humans and invasive plant species. Despite the water challenges facing the urban populations, Kenya possesses sufficient water resources to meet demand if the available resources are properly managed. Several initiatives are being put in place in Kenya to mitigate the water challenges and protect water resources in Kenya. These include enacting of water policies to protect water catchment areas, reduce pollution and enhance access to clean water.

Groundwater Quality Assessment for an Indian Urban Habitat： A GIS Approach

Groundwater is an essential source of drinking water for many Indian urban habitats. Large numbers of people consume ground water instead of municipal tap water due to contamination of tap water. Groundwater is extracted from thousands of bore wells, and used for potable purpose without proper testing and treatment. This paper describes a groundwater quality monitoring strategy and database model developed for Gulbarga city, located in Karnataka, India. Sampling wells are selected one each in 55 wards of the city corporation having easy access for regular sampling. Various attributes of sampling wells including their spatial coordinates, location address and a photograph are registered for ready recognition on site. Water samples are collected and analyzed for various physico-chemical parameters. Spatial coordinates and levels of sampling points are measured on site using a hand held GPS instrument. Gulbarga city map is digitized. A GIS database of the measured spatial and water quality data is developed using ArcGIS Desktop 9.3, and ground water quality maps are prepared which may serve as useful tools for developing policy, and regulatory mechanism for sustainable groundwater use.

Optimization research on supply and demand system for water resources in the Chang-Zhu-Tan urban agglomeration

Using system analysis theory and methods, a dynamic model of a water resource supply and demand system was built to simulate trends in the supply and demand of water in the Changsha-Zhuzhou-Xiangtan （Chang-Zhu-Tan） urban agglomeration for the period 2012 to 2030. Four scenarios were examined; namely, a traditional development model, an economic development model, a water-saving model, and a coordinated development model. （i） The problem of balancing water resource supply and demand is becoming increasingly conspicuous with a growing population and a rapidly developing economy. （ii） By 2030, water demand is set to reach a total of 105.1 × 10^8 m^3, with a water supply of 5.4 × 10^8 m^3. A coordinated development model for water resource supply could meet the growing demands of socio-economic development, and generate huge comprehensive benefits. This will be the best solution for the development and utilization of a water resource supply and demand system in the Chang-Zhu-Tan urban agglomeration. （iii） We should accelerate the construction of water conservation projects, strengthen the management of water conservation, optimize economic structures, enhance our awareness of the importance of protecting water resources, hasten the recycling of waste water and environmental improvement, and promote utilization efficiency, and support the capabilities of water resources to meet our expectations.

Trend of urban system structure under the restriction of water and land resources in Xinjiang

根据在 Xinjiang 影响城市的开发和城市的系统结构的水和陆地资源上的研究，这篇论文分析利用地位和城市的水资源的缺乏。城市的水资源的消费和浪费在一个增加趋势，这被考虑。然而，在 Xinjiang 的大多数城市和镇在水资源的缺乏水资源的废物是严肃的，特别在小镇上。megapolis 和中等城市的发展被有限陆地资源显然限制。尽管有扩展小城市和镇的相对大的空格，水和陆地资源的输出好处是低的。为了完成城市的系统的顺序的扩大，在 Xinjiang 组织，在都市化的快速的发展拿一个圆和三条带和节俭资源的策略的城市的空间发展模式被建议。

Research and Experience Reference on London’s Response to Climate Change in the Twenty-first Century

London’s approaches to tackling climate change after the 21st century are multifaceted and relatively systematic.The aim of this research paper is to analyse London’s actions in response to climate change and to draw out what valuable lessons London has for the world in terms of its response to climate change.This paper provides an in-depth analysis of London’s policies and actions on climate mitigation in the areas of“greenhouse gas emissions”and“energy infrastructure”,and climate adaptation actions in the areas of“city green belt and urban afforestation”,“UHI and thermal crisis management”and“water supply infrastructure and sustainable drainage”.It then examines the positive aspects of these actions to determine what London has to say about climate change to the rest of the world and other cities.This paper also discovers that to effectively mitigate and adapt to climate change,London has not only established carbon reduction targets,but also created a large academic research network,represented by the LCCP.At the same time,London has developed a scientific climate change adaptation planning framework(P2R2)that focuses on four key areas:Economic,environmental,health,and infrastructure sectors,and three types of risks:Flooding,heat,and water supply,and emphasizes the dynamics and flexibility of each adaptation strategy.

新时期阿克苏地区城乡供水安全保障体系探析

本文以阿克苏地区城乡供水安全保障体系为例,在对当地城乡供水现状及存在的问题进行分析的基础上,结合未来发展和新时期供水思路,因地制宜,积极推进城市群供水、城乡一体化供水和集中供水,实施多水源供水和应急备用水源工程,构建与当地经济社会发展相适应的城乡供水安全保障体系,大大提高了供水保障程度。研究成果可为其他地区城乡供水提供一定的参考和借鉴。

韧性城市建筑“平急结合”设计给排水应对关键措施探索

简介韧性城市建筑中适用于临时隔离收治点的建筑类型,提出建立临时隔离收治点“平急结合”设计的标准体系构想,解析作为临时隔离收治点的新建建筑、既有建筑在设计或改造中的给排水应对措施,重点就条件预留、用水定额、系统定型、管道布设、设备选用、污水处理等方面进行深入探索。

对某城乡供水工程自动化控制的设计和应用研究

城乡供水自动化是解决农村饮水安全的重要措施,能够有效保证供水工程的管理决策能力和应用服务水平。总结了某城乡供水项目中自动化控制的设计和应用,不仅能有效的弥补水利工程建设过程中存在的不足,此外在实现水利工程长远发展、提高水利工程管理水平中也发挥了重要性作用,可以实现城乡供水后期运行中节水、减员、降本、增效的功能优势,推动了城乡供水的均等化服务,有效巩固当地的脱贫攻坚工作。

我国城市供排水在线监测技术发展与标准化历程

随着我国供排水设施规模快速增长、各类新兴业务的大量涌现以及在线监测技术的不断进步,供排水在线监测技术得到了快速发展和应用。为解决业务需求和技术标准化需求,研究者对在线监测设备的性能与运行维护要求、监测系统布局优化方案等方面开展了一系列研究。随着在线监测技术的逐渐成熟,该技术在供水全流程监控、排水设施运行监控与问题诊断、海绵城市建设效果评价、水环境治理中的排污溯源等方面得到了广泛应用。同时,为规范供排水在线监测技术的应用,我国供排水在线监测技术标准经历了从无到有并逐步完善的过程,建立了以行业标准为主、以地方标准和团体标准作为补充的标准体系。

基于等效场景的供水管网抗震可靠性评估

供水管网抗震可靠性是满足用户在可能地震作用下用水需求的能力。目前,多数供水管网抗震可靠性评估采用蒙特卡洛模拟产生大量的震损样本进行评估。然而,此方法在评估大型、复杂管网时,将带来极大的工作量和超高的时间成本。为了克服这些问题,提出等效场景方法以提高计算效率。首先,利用震损场景生成后验概率;然后,利用后验概率生成等效场景;最后,通过等效场景确定节点可靠性指数和系统可靠性指数。将文中所提算法与传统蒙特卡洛方法的模拟结果进行对比。研究结果表明:基于后验概率生成等效场景方法是可行的;地震烈度8度时采用100个等效场景评估其可靠性,存在少数评估误差超过10%的节点,其余小地震烈度评估误差均小于5%。将100个等效场景提高至250个,可将评估误差控制在5%以内。因此,该文提出的算法可以在保证结果准确的同时提高计算效率。

城市轨道交通车站空调冷冻水系统定温差变供水温度和大温差控制策略转换条件研究

[目的]为实现城市轨道交通车站空调冷冻水系统在定温差变供水温度和大温差两种工况下的整体能耗最低,需对这两种控制策略的转换条件进行研究。[方法]以郑州某城市轨道交通车站为例,基于TRNSYS(瞬时系统模拟程序)建立定温差变供水温度和大温差两种工况下的空调冷冻水系统模型,在满足空调冷冻水系统末端制冷量需求的前提下,分别研究冷冻水温差不变、供水温度为7~12℃,以及供水温度不变、供回水温差为5~10℃时对空调冷冻水系统能耗的影响。[结果及结论]两种控制策略的转换条件为:负荷率小于等于40%时,使用定温差变供水温度控制策略更节能;负荷率大于50%时,更适合采用大温差控制策略。该转换条件不仅能满足车站人员舒适度的要求,还实现了两种控制策略联合调控的目标,最终达到降低空调冷冻水系统整体能耗的目的。

大直径城市供水管道水锤作用监测与计算方法研究

随着我国城市建设的发展,长距离供水管道应用众多,而在长距离供水管道设计过程中水锤作用不可忽视。使用高频动态压力传感器进行现场监测试验,对比传统水锤方程组和“FSI四方程模型”水锤计算的结果,并同时基于ABAQUS数值模拟软件开展相关数值模拟,对大直径供水管突然关机时产生的水锤作用进行研究。结果表明:在水锤作用下压应力最大部位位于管顶、管底内侧,拉应力最大部位位于管腰内侧;壁厚与应力和位移呈正相关,管径与应力呈正相关且与位移呈负相关,而管道埋深对其应力和位移的影响很小。研究的计算结果与数值模拟结果接近监测真实值,对水锤模拟有一定指导意义。

基于聚类分析法的江苏省城乡统筹供水规划模式研究

在充分调查江苏省城乡统筹区域供水情况的基础上,分析每个供水片区水源地布局及取水规模、水厂布局及供水规模、人口密度、经济社会发展水平等特征;采用聚类分析法,以单个水源地服务面积、单个水源地服务人口和单个水源地取水规模为主要分类指标,综合考虑每个供水片区水厂数量、供水服务面积等因素,将江苏省供水规划模式分为适度集中、中度集中及高度集中供水规划模式,分析不同供水规划模式特征及适用范围;采用FISH判别分析方法,构建区域供水规划模式判别函数,为规划模式的选择提供数学函数。

以“节水优先、空间均衡、系统治理、两手发力”治水思路为引领 全力推动新阶段城乡供水高质量发展

践行“节水优先、空间均衡、系统治理、两手发力”治水思路,推动城乡供水高质量发展,是满足人民群众美好生活向往的基础保障。规模发展、一体建设、数字赋能、专业运营、系统治理,形成宁夏城乡供水高质量发展综合体系。针对短板弱项,从优化工程水网布局、构建水质安全体系、探索数字孪生供水、促进城乡均等服务等方面进行了探讨,提出了对策。

基于组合赋权-集对分析的城市供水安全评价

为更精准地评价城市供水安全,将集对分析法与主客观组合赋权法相结合,建立区域城市供水安全评价模型,即用最小相对信息熵原理确定指标综合权重并耦合到指标联系度中,构建出城市供水安全的组合赋权-集对分析的评价体系,通过五元减法集对势确定城市供水安全等级,并对昆明市2011~2020年的供水安全评价划分安全等级。结果表明,2011~2013年昆明市供水处于安全等级,其中2011、2012年更倾向于基本安全等级;2014~2020年昆明市供水处于非常安全等级但更倾向于安全等级,供水状态相对安全和稳定。所提方法一定程度上解决了城市供水安全评价等级中的不确定性和多指标性问题,为城市供水安全评价提供了一种新思路。

那位水库工程分层取水设计

凌云县那位水库是典型高坝小库容水库,库水位年度变化大。库区位于山区,受暴雨等影响,水质变化大。那位水库作为凌云县城区第二水源采用分层取水,根据不同的季节和水质,分别取水库表层水、中层水、底层水,可以较好解决取优质水问题。本文介绍了那位水库分层取水设计方案。