Experience in using a guide vane design with a “floating” lower bearing

Conclusion The use of the floating bearing of the vanes in the lower ring of the gate apparatus makes it possible to reduce the cycle and labor expenditures of manufacture at the plant and on assembly of the gate apparatus with a substantial improvement of the quality of assembly.Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 4, pp. 45–47, April, 1984.     

The Afghan water law: “a legal solution foreign to reality”? 1

In this article the suggested permit and licence systems included in the draft Afghan Water Law of 2008 (superseding those laws of 1981 and 1991) are examined by comparing them with main canal data from two pilot studies within the Kunduz Basin. The comparison highlights the difficulty of making these proposed legal frameworks operative. Overall, it appears that the sections within the law on permits and licences are not implementable within or even useful for the traditional irrigation systems, but mainly play into the hands of the national hydrocracy and please international donors.     

The new “Act on Waste” in Hungary

The environmental issues in Hungary have high priority nowadays especially on the field of waste management. The major driven force behind it is the intention to meet the related EU engagements, besides the predecessor Act was fairly outdated. The draft of the new “Act on Waste” triggered special focus even from the international press and the interested waste management companies due to its reforming plans. According to the interest of different stakeholders, lobbying and discussions took place with the Government. So, the article aims to give a short introduction on the most important changes, especially from the aspect of municipal waste management companies.     

Design Considerations for Hydropower Development In a Water Distribution System

Installation of a hydraulic turbine in a water distribution system involving long pipeline reaches requires several unique design considerations. For a fixed speed unit, the selection of design points for head and flow needs to be optimized to provide an operating envelope that would maximize the return on the investment given the widely varied flow and pressure conditions imposed by the water distribution system. The selection of a turbine design speed is essential in facilitating runner design, which must minimize the hydraulic pressure transients on turbine runaway that may result in overstressing the existing pipelines. Method and approach to evaluate these considerations are outlined. Relevant results for the selected design are presented using the 4.3 MW Rancho Penasquitos Pressure Control/Hydroelectric Facility as an illustrative example. Licensing requirements for small inline hydroelectric facilities are also briefly discussed.     

“Good Dredging Practices”: The Place of Traditional Eco-livelihood Knowledge

Residents of most rural communities in developing countries depend on surface water resources for their livelihoods. The development and management of this vital resource should as much as possible take into consideration local socio-economic priorities if sustainable development is to be achieved at local levels in these countries. Inland river dredging is a water resource management strategy usually aimed at improving water courses for navigation, land reclamation and or mitigate flood in the dredged catchment. Dredging operations like most development projects have impacts that are often localised, and benefits that could be local, regional or national. “Good dredging practices”, GDP, in industrialised countries have been aimed at balancing national/regional economic benefits, technical feasibility and environmental protection. These practices rely heavily on the quality, and quantity of available relevant base-line data. In most developing countries there is a dearth of baseline data, and often national/regional economic gains do not necessarily translate into local livelihood benefits. Hence, the basis of GDP should be extended to incorporate local livelihoods priorities, without ignoring the relevance of scientific data when it is available, the issue of technical feasibility, environmental sustainability and economic viability. This approach is relevant to the demand for equitable development in the developing world; could be used in conjunction with traditional eco-livelihoods knowledge in developing or determining appropriate approaches for sustainable surface water resources management, as well as reducing environmental conflicts between stakeholders.     

An Improved “Dynamic Control Operation Module” for Cascade Reservoirs

Reservoirs are one of the most efficient projects for water resources management, and also play an important role in flood control and conservation. Dynamic control of the reservoir flood limited water level (FLWL) is considered as an effective factor to ensure safety of the flood control during the flood season. The maximum allowed water level of cascade reservoirs is also a fundamental key element for implementing reservoir water level dynamic control operation. In this paper, we discussed and improved “Dynamic Control Operation Module for Cascade Reservoirs” (DCOMR). Therefore, a set of new formulas and new methodologies were proposed (NDCOMR) which considers intermediate variables forecast information, the release of the upstream reservoir and interval flow forecast information in effective lead times, which is applied to the dynamic operation of the maximum allowed water level of cascade reservoirs. The Bikou and Miaojiaba cascade reservoirs were selected as a case study. Based on numerical experiment results, the maximum allowed water level of cascade reservoirs at current time determined by NDCOMR was much safer than that determined by DCOMR. The NDCOMR is more rational and safer than DCOMR for flood control, without the need of reducing flood control standard.     

The Accuracy and Reliability of Traditional Surface Flow Type Mapping: Is it Time for a New Method of Characterizing Physical River Habitat?

Surface flow types (SFTs) are advocated as ecologically relevant hydraulic units, often mapped visually from the bankside to characterize rapidly the physical habitat of rivers. SFT mapping is simple, non‐invasive and cost‐efficient. However, it is also qualitative, subjective and plagued by difficulties in recording accurately the spatial extent of SFT units. Quantitative validation of the underlying physical habitat parameters is often lacking and does not consistently differentiate between SFTs. Here, we investigate explicitly the accuracy, reliability and statistical separability of traditionally mapped SFTs as indicators of physical habitat, using independent, hydraulic and topographic data collected during three surveys of a c. 50 m reach of the River Arrow, Warwickshire, England. We also explore the potential of a novel remote sensing approach, comprising a small unmanned aerial system (sUAS) and structure‐from‐motion photogrammetry (SfM), as an alternative method of physical habitat characterization. Our key findings indicate that SFT mapping accuracy is highly variable, with overall mapping accuracy not exceeding 74%. Results from analysis of similarity tests found that strong differences did not exist between all SFT pairs. This leads us to question the suitability of SFTs for characterizing physical habitat for river science and management applications. In contrast, the sUAS–SfM approach provided high resolution, spatially continuous, spatially explicit, quantitative measurements of water depth and point cloud roughness at the microscale (spatial scales ≤1 m). Such data are acquired rapidly, inexpensively and provide new opportunities for examining the heterogeneity of physical habitat over a range of spatial and temporal scales. Whilst continued refinement of the sUAS–SfM approach is required, we propose that this method offers an opportunity to move away from broad, mesoscale classifications of physical habitat (spatial scales 10–100 m) and towards continuous, quantitative measurements of the continuum of hydraulic and geomorphic conditions, which actually exists at the microscale. Copyright © 2016 John Wiley & Sons, Ltd.     

Numerical modelling: a tool for better constructed wetland design?

There is a need for a simplified computer-based design tool for subsurface flow constructed wetlands (CWs) which is based on process-based numerical models. Parameters of existing design guidelines and rules have been derived from experiments under specific conditions. Therefore designing CWs using these parameters is limited to these conditions (i.e., temperature, wastewater composition, filter material, etc.). Process-based numerical models describe the main processes in CWs in detail. If the design of CWs is based on these models it will be possible to design CWs for a variety of different boundary conditions and therefore the main limitation of existing design guidelines and rules could be overcome. The use of process-based models is currently limited mainly due to their complexity in structure and use. To make numerical modelling a useful and applicable tool for design, a simplified computer-based design tool that does not require special knowledge of numerical modelling is needed. Additionally, simple models for pre- and post-treatments are also required. Besides allowing designs for various boundary conditions, design tools based on process-based models can also predict the dynamic behaviour of the designed system thus showing e.g., the higher robustness of CWs against fluctuating inflows and peak loads compared to other treatment solutions. Such a tool could increase the quality of CW design and the acceptance and use of CW simulation in practice.     

黄河“八七”分水方案实施30 a回顾与展望

回顾了黄河"八七"分水方案出台的历史背景、研究历程以及在实践中不断细化和完善的过程,分析了1999年统一调度之前和之后两个时段的运用情况和效果,提出了变化环境下流域水资源面临的新形势并进行了展望。"八七"分水方案是我国大江大河第一个流域分水方案,对于国家推进水资源科学分配和高效利用具有重大突破和示范意义,在运用中先后开展了"八七"分水方案细化、新径流条件下分水方案完善、用水总量控制红线制定等一系列工作,分水方案得到持续细化、深化、发展和完善,有力支撑了黄河流域水资源管理,成为流域管理重要的技术文件。运用30 a来,"八七"分水方案以及黄河水资源管理实践有效控制了流域用水需求增长,协调了各省(区)用水关系,支撑了流域经济社会可持续发展与生态环境维持,实现了黄河干流20 a不断流。未来黄河流域面临的水资源需求仍将呈现一定的刚性增长,流域水资源管理的关键问题是如何缓解水资源对流域经济社会发展的制约,支撑生态环境良性维持。     

“Erosion Control on Surface Mined Watersheds: a Modelling Approach”

ABSTRACT

This article describes the efforts of the Mexican government toward more efficient management of water resources. Inaccordance with the Mexican Constitution, municipal governments have been responsible for urban water and sanitation services. However; in practice most municipalities have weak finances and little expertise in managing water systems and the federal government still plays an important role in the management and financing of water infrastructure.

The article highlights the current state of the water sector in Mexico, including some of the main aspects of the legal and institutionalframework. It discusses the main difficulties faced by the municipalities in accomplishing their task. The strategy of the federal government, in order to achieve better urban water management, has focused on four main policies: changes in the legal and institutional framework for water management, further decentralization, new financing schemes, and greater private sector involvement. It concludes that flexible approaches should allow municipalities to find appropriate institutional, financial, and technical solutions.     

对生产力测定中“叶绿素a的测定”方法的探讨

目前,生物监测已成为水质监测、评价的重要手段之一。1999年,按照河南省环境监测中心站的要求,各市站对湖泊(水库)监测时增添叶绿素a项目的测定。但是在测定中发现生产力测定中“叶绿素a的测定”方法存在着一些需要探讨的问题。我们进行了多次对比实验研究,改进了方法。新方法具有简便、快速、准确等特点。     

When are Partnerships a Viable Tool for Development? Institutions and Partnerships for Water and Sanitation Service in Latin America

Partnerships are increasingly becoming unpopular in Latin America, they have narrowly been analysed in the context of the international political agenda and criticized for bringing benefits only to the private sector and not to the public sector and society at large. Nevertheless, there are successful experiences for providing water and sanitation at local level. The questions are: Are local level successful experiences the product of a partnership? Was it necessary to build partnerships to add value to the community presence and informal actors? What are the advantages of partnerships at local and national scale? The case studies presented demonstrate that actors need to have an incentive to work together and to build trust. The context in which they operate is also relevant, and in Latin America it is needed a strong national legal institutional framework if partnerships or any agreement should be an alternative to public delivery of water and sanitation. This paper analyses the context in which water and sanitation is delivered in peri-urban areas based on case studies, identified actions for effective provision and on discussion of the institutional framework options and partnership implementation at local and national level. This paper does not advocate partnerships per se; nor are these seen as the problem.