Antifragility and the development of urban water infrastructure

Abstract

Antifragility is a system property that results in systems becoming increasingly resistant to external shocks by being exposed to them. These systems have the counter-intuitive property of benefiting from uncertain conditions. This paper presents one of the first known applications of antifragility to water infrastructure systems and outlines the development of antifragility at the city scale through the use of local governance, data collection and a bimodal strategy for infrastructure development. The systems architecture presented results in a management paradigm that can deliver reliable water systems in the face of highly uncertain future conditions.     

水轮机调节系统的空载特性仿真

介绍了水轮机调节系统空载动态特性的仿真结果,给出了空载频率波动和空载扰动的仿真曲线.仿真结果有助于加深对水轮机调节系统基本原理的理解,也有助于了解被控制系统参数(调节对象)和水轮机控制系统(调速器)参数对水轮机调节系统空载动态特性的影响.     

水布垭电厂交直流供电系统的可靠性分析

介绍了水布垭电厂110 kV厂用电源系统、400 V厂用电源系统、220 V直流电源系统的现状,分析了厂用电源系统可靠性的影响因素,对3种电源系统在运行中存在的问题提出了具体措施。     

An iterative method to optimize the operation of reservoir systems

Optimization of long-term operation of real-world reservoir systems by dynamic programming has been studied. Computer time requirements make it necessary to use iterative methods in the case of multi-reservoir systems. State-incremental dynamic programming provides a reasonable rate of convergence for serial systems when initial policies are suitably chosen. A new method is proposed that combines dynamic programming with successive approximations and state-incremental dynamic programming. Incremental sequential dynamic programming is especially useful for systems of complex configuration which cannot be optimized with other iterative methods due to very slow convergence. Choices of initial policy, state increment, and the number of states to be considered in each iteration are investigated in two case studies.     

东江流域水资源承载能力评价

根据东江流域水资源系统与社会经济系统、生态环境系统之间的相互影响与作用,建立东江流域水资源承载能力评价体系,运用模糊综合评判法对东江流域水资源承载能力进行评价。评价结果表明,东江流域水资源承载能力呈现中上游高、下游低的分布趋势。     

加强小型农田水利工程运行维护管理的对策及措施

作为农业发展的最基础条件,小型农田水利建设是保障农业可持续发展的一个极为重要的因素。然而,小型农田水利工程运行维护管理制约着农田水利事业的发展。通过对小型农田水利主要建设模式的介绍,指出小型农田水利工程运行维护管理中存在的问题,并提出相关对策及措施,以期使其发挥应有的效益,更好地服务于生活和生产。     

小型农田水利工程运行管护中的主要问题和建议

近年,国家对小型农田水利工程建设的投入逐年增多,如何保证工程建后的正常运行与管护并持续发挥工程效益,已经成为当前亟待研究解决的问题。在分析当前小型农田水利工程管护中存在问题的基础上,提出了相应的建议。     

A Real Option Perspective to Value the Multi-Stage Construction of Rainwater Harvesting Systems Reusing Septic Tank

Recently, rainwater harvesting systems have received increased attention due to their capability for adapting to water scarcity and climate change. However, a key obstacle to the implementation of rainwater harvesting systems is that they are often not financially feasible given difficulty in determining optimal system size. A key premise of previous studies was that all rainwater harvesting systems are constructed in a single construction event even though it is possible to construct a system in multiple stages. This assumption limits managerial flexibility in the construction of rainwater harvesting systems, which is particularly valuable in scenarios where it is difficult to forecast future rainfall patterns. Therefore, we propose a multi-stage system expansion strategy for the implementation of rainwater harvesting systems using decommissioned septic tanks under scenarios of uncertainty in rainfall from a real option perspective as a means to improve the financial feasibility of implementing rainwater harvesting systems. We tested this strategy by evaluating a proposed rainwater harvesting system for a midsize apartment complex in Jeonju, South Korea. The multi-stage expansion strategy generated an option value of 9,896 USD. This study will help to improve the financial feasibility of rainwater harvesting systems by adding the value of managerial flexibility through a sequential expansion of RWH systems as new information becomes available.     

A comparison between the theory and reality of full-scale step-feed nutrient removal systems.

Capacity enhancement and volume reduction benefits of step-feeding fully aerobic bioreactors has been well documented. Application of step-feed technology to biological nutrient removal (BNR) systems, particularly those removing nitrogen alone or both nitrogen and phosphorus, is relatively new to the industry. In recent years, a number of full-scale step-feed facilities have been brought into service. This paper reviews nine full-scale step-feed biological nutrient removal systems--both nitrogen removal alone, and nitrogen and phosphorus removal. The objective is to compare the theoretical benefits of such systems with their actual operation. The predicted benefits of reduced bioreactor volume or increased process capacity, reduced energy usage, more robust nitrification performance, and the flexibility to tune (or de-tune) nitrification efficiency were verified in full-scale systems. Equations are also presented that may be used in the prediction of step-feed benefits. There are two primary drivers for considering a step-feed biological reactor system: 1. Reduced bioreactor volume for a defined capacity or performance or increased process capacity given a fixed bioreactor volume. 2. More robust nitrification performance. Full-scale operation of these step-feed nutrient removal systems provides a real world basis for the claimed benefits of step-feed operation. These systems have uniformly shown additional capacity. A number of them have also exhibited more robust performance, especially during storms. Where possible, side-by-side comparisons of full-scale step-feed systems with non-step-feed systems have exhibited greater process reliability and flexibility.     

Estimation of phosphorus loads from septic systems to tributaries in the Canadian Lake Erie Basin

The contribution of septic systems to watershed nutrient loads is poorly quantified although they are often cited as potentially important nutrient sources. The study used a geospatial model to estimate P loads from septic systems to the tributaries of the Canadian Lake Erie Basin to inform Lake Erie nutrient management initiatives. There is currently no inventory of septic systems in the Lake Erie Basin (e.g., numbers and locations of septic systems). Therefore a geospatial model was developed to automatically locate individual septic systems and to use these locations to estimate P load contributions to tributaries. The model was first tested on three subwatersheds in the Canadian Lake Erie Basin before being applied across the Basin. Present-day basin-wide P load estimates reveal that: (i) only a fraction of septic effluent is currently reaching the tributaries due to slow transport and other delays, as well as (ii) P attenuation in the subsurface, range from 23 ± 11 to 68 ± 32 MT/yr. Based on these estimates, septic systems may currently contribute 1.7 ± 0.8–5 ± 2.3% of the P loads to Lake Erie from Canada. However, maximum P load estimates and transient model results show that the contribution of septic systems to P loads will increase over time as slow moving septic-derived groundwater P plumes reach tributaries if aging septic systems are not maintained. This study provides widely applicable new knowledge and methodology; as well as specific findings needed to inform nutrient and septic system management in the Lake Erie Basin.     

Characterisation of the Sensitivity of Water Resources Systems to Climate Change

This paper offers a methodology that enables characterisation of the behaviour of water resources systems under the impact of climate change through assessment of sensitivity patterns in a wide range of hydrologic variations produced by such change. Analysis is based on the application of two indicators that, in turn, draw on the results of a system optimisation model. Under this methodology the potential sensitivity of water resources systems in the cases of different climate projections are visualised, allowing those systems that require special attention in their adaptation to climate change to be identified. The methodology is applied to three basins located in Spain: Guadalquivir, Ebro and the Spanish part of the international basin Duero.     

单点系泊船舶的动态分岔特性研究

研究了潮流作用下单点系泊船舶的动态分岔特性。应用高维微分动力系统Hopf分岔的直接代数判据，得到了潮流作用下单点系泊系统发生Hopf分岔的充要条件，并应用于油轮系泊运动的Hopf分岔研究。以潮流速度和系缆长度为控制参数，在参数平面上给出了Hopf分岔集，应用数值仿真计算检验了理论分析结果，两者相当吻合。由此在参数空间中确定了潮流作用下单点系泊船舶的非线性动力学特性，为系泊系统设计参数的选择提供了理论依据。     

Institutional organizers and collective action: the case of water users' associations in Gujarat,India

Setting up water users' associations (WUAs) and involving them in the management of delivery systems is an important innovation in improving the performance of public irrigation systems. Most Indian states are in a great hurry to turn over management of “below-the outlet” systems to WUAs. Yet the crucial link between the work done by the institutional organizers who set up these WUAs, the efficacy of the WUAs and the eventual performance of the irrigation systems remains unexplored. This paper attempts to explore this link. It shows that overdrive in the formation of WUAs may reduce their institutional sustainability.     

A Comparative Study of the Performance of Public Water Rights Allocation in China

Pubic water rights allocation, in which water resources are allocated to users administratively as shared public property, is an effective and powerful policy for water resource management. Dozens of public water right allocation systems have been established in China since 1998 without any unified standard across the country. An indicator-based assessment approach, based on equity, efficiency and sustainability, is proposed in this study to evaluate the performance of public water rights allocation systems in China in a quantitative way. The approach was applied in 11 river basins of China in which water rights have been defined. The results show that the performance of the allocation systems depends on the spatial density and exploitation ratio of the water resources. The performance of allocated water rights systems is better in river basins with greater resource densities and smaller water exploitation ratios. This assessment approach is very useful for evaluating policy options for public water rights allocation with appropriate consideration of the local conditions of the river basins.     

MB80在大型抽水蓄能电站计算机监控系统的应用

讨论了大型抽水蓄能电站监控系统的现状,分析了现有系统的优缺点;介绍了国网南京自动化研究院自主创新、具有完全知识产权的MB80型智能可编程控制器;针对大型抽水蓄能电站控制的特点,讨论了国产化系统需研究的关键技术;最后介绍了以MB80为核心控制平台的大型抽水蓄能电站计算机监控系统.     

河湖水系连通优化的内涵特征与准则初探

针对新时期建设具有水资源、水环境、水生态、水灾害统筹治理功能的国家现代水网的需求,如何进行河湖水系连通优化,尽可能降低负面效应,最大程度发挥综合正效应,是河湖水系连通研究领域急需解决的问题。结合新时期河湖水系连通多功能需求,提出了河湖水系连通优化的概念内涵特征,并对概念内涵和特征进行了初步分析和探讨。在此基础上,结合我国水安全形势对河湖水系连通的新需求,从“十六字”治水思路、“十二字”原则、“三先三后”原则、工程与管理并重、遵循自然和历史规律等方面对河湖水系连通优化应遵循的准则进行了初步探讨,以期为河湖水系连通优化的深入研究提供借鉴。     

人工砂石料智能设计系统研究

在分析人工砂石料系统的特点及其计算机辅助设计应用现状的基础上，提出了一种多Agent协同工作的人工砂石料智能设计系统的实施方案。由野外勘测资料、采料场优选、工艺流程设计、堆场规划、加工厂布置、技经评估、项目管理7个Agent和工程数据库配合构成的系统，易于实现人工砂石料系统设计的智能化、集成化、网络化，能大幅度提高设计质量和效率。     

金安桥水电站工程建设管理综述

金安桥水电站实行业主负责制、工程建设监理制、招标投标制和合同管理制。工程建设中,业主发挥了核心主导作用,建立了科学规范的工程建设管理体系,并在工程实践中健全并不断改进。质量目标明确,各项规章制度贯彻落实到位,为工程建设的顺利进行提供了有力保障。     

Discussion of the enabling environments for decentralised water systems

Decentralised water supply systems are becoming increasingly affordable and commonplace in Australia and have the potential to alleviate urban water shortages and reduce pollution into natural receiving marine and freshwater streams. Learning processes are necessary to support the efficient implementation of decentralised systems. These processes reveal the complex socio-technical and institutional factors to be considered when developing an enabling environment supporting decentralised water and wastewater servicing solutions. Critical to the technological transition towards established decentralised systems is the ability to create strategic and adaptive capacity to promote learning and dialogue. Learning processes require institutional mechanisms to ensure the lessons are incorporated into the formulation of policy and regulation, through constructive involvement of key government institutions. Engagement of stakeholders is essential to the enabling environment. Collaborative learning environments using systems analysis with communities (social learning) and adaptive management techniques are useful in refining and applying scientists' and managers' knowledge (knowledge management).     

Introduction of centrifugal-jet sprayers in the deaeration systems of the PGU-39 steam-gas units at the Sochi thermal power plant

The operation of various types of deaeration systems is analyzed and experience with introducing centrifugal-jet sprayers in the condenser and deaeration towers of boiler drums is described.