Fish-protection structures of irrigation systems

Translated from Gidrotekhnicheskoe Stroitel'stvo, No. 9, pp. 21–24, September, 1990.     

Trends in trickle irrigation systems development

As water availability becomes an increasing constraint on food production, more attention must be given to exploiting crop characteristics such as tolerance of water scarcity or saline soils, and the development of efficient water application methods. Water application methods vary, among other things, in their efficiency of water use and related yield, capital investment, longevity of equipment, labour and associated high technology. Trickle irrigation is one method which has shown great promise in these respects. Consequently its usage has expanded exponentially in the last decade and now includes many field and orchard crops which were traditionally irrigated under sprinkler or surface irrigation methods. Water saving, the ease of implementation and related higher yields per unit of water and per unit of area are a few of the main characteristics of trickle irrigation success.     

Monitoring and evaluation of Nigeria's irrigation systems: The case of the Bakolori irrigation project

One of the major banes of water resources development projects in Nigeria is lack of effective monitoring and evaluation. This apparent neglect has resulted in the inability to complete projects within the stipulated period, escalation of costs, poor design and construction works, and inevitably poor performance. This article reports the result of a diagnostic survey of the Bakolori Irrigation Project (BIP), one of the most controversial schemes in Nigeria. It is suggested that project monitoring and evaluation should be made compulsory on all irrigation projects in Nigeria, if they are to make any meaningful beneficial impact on the rural development process.     

Principles of evaluating the ecological reliability of irrigation systems

Translated fromGidrotekhnicheskoe Stroitel'stvo, No. 5, pp. 37–41, May, 1993.     

Rapid appraisal for improving existing canal irrigation systems

Low levels of performance on canal irrigation systems in developing countries are a major concern of many governments and aid agencies. A wide range of actions is possible to improve performance. The choice, mix and sequence of actions are often determined by professional preferences or national programmes but to fit well should be tailored for each individual irrigation system. Rapid rural appraisal techniques offer a cost‐effective approach, either through teamwork or through irrigation managers doing it themselves. In order to improve rapid appraisals, practitioners are encouraged to write about and share their techniques and experiences.     

墨西哥小型灌区的改造经验

在墨西哥,有3.9万多个被称为灌溉单元的小型灌区,大体上,这些灌区都面临着用水户组织困难,灌区管理、运行落后,灌区保存、维持困难等问题.墨西哥政府通过国家水利委员会,采取了基于鼓励用水户组成有限责任公司的民间协会的措施.这些协会是基于联合投资基金资助的两个项目成立的,而在联合投资基金中,民间投资不能超过总投资的50%.这两个项目分别是水电高效利用和农业水利设施充分利用.基于组成用水协会及其与基础设施的恢复、续建和相关技术的联合应用的墨西哥灌区改造,是促进小型灌区可持续发展的可行途径.     

固定式喷灌系统经济管径的计算方法

在分析了固定式喷灌系统的管网投资、年运行费用与管径函数关系的基础上,利用工程经济分析中费用最小化准则和非线性规划理论,建立了求解喷灌系统管网经济管径的数学模型,并给出了无约束条件直接求解经济管径的计算式．     

大棚蔬菜西红柿节水灌溉制度试验研究

蔬菜生产在密云县已经成为促进农民增收致富和农村经济发展的主导产业。因此研究资源型缺水地区大棚蔬菜采取非充分灌溉条件下的节水高产高效的灌溉制度和相关技术措施,通过减少颗间蒸发及作物蒸腾,降低棚内湿度,减少病虫害,提高产品质量和产量,增加农民收入。这样有利于指导今后的蔬菜灌溉,达到节约农业用水和增产、增效、降低ET值的目的。     

M&O guidelines for turnover of irrigation systems to farmers

A process has been developed for converting an irrigation project presently being operated by the government (agency‐managed irrigation system) to a farmer‐managed irrigation system. This joint management turnover process has three phases: (1) initial organization; (2) joint management agreement; and (3) joint management implementation. Maintenance and operation (M&O) guidelines are provided for achieving turnover of system management to farmers.     

圆形喷灌机低压阻尼喷头水滴直径分布规律的试验研究

为了提高机组喷洒均匀性、降低对土壤作物的打击强度,近几年国内圆形喷灌机逐渐安装低压阻尼旋转喷头,以替代非旋转低压喷头。本文采用面粉法对R3000和A3000低压阻尼喷头在安装3种喷嘴(直径为2.98、4.96和6.95 mm)和2种工作压力(100和140 kPa)下的水滴直径分布规律进行了试验,分析了水滴平均直径和总体水滴直径分布,探讨了水滴直径与喷头转速、喷嘴直径及工作压力的关系。结果表明,在相同工作压力和喷嘴直径下,A3000喷头转速要快于R3000喷头,但射程和末端水滴直径均有所减小。在相同喷嘴直径下,两种喷头随着工作压力的增大,射程均有所增大,但末端水滴直径呈变小趋势;在相同工作压力下,随着喷嘴直径增大,喷头射程均呈增大趋势,但末端水滴直径变化不显著。A3000喷头总体水滴直径分布范围比R3000喷头窄,不同工况下测得的A3000喷头水滴中数直径比R3000喷头小3.6%~8.9%。两种喷头径向不同位置处的水滴平均直径与喷头距离呈指数关系,中数直径随工作压力增大或喷嘴直径减小而变小。     

Modernization of irrigation systems in Spain: review and analysis for decision making

Abstract

This article presents a method for analyzing the economic feasibility of modernizing irrigation systems. By using substitution relationships between two variables, one can determine irrigation performance and farm profit ?above which modernization would be justified from an economic point of view; ?and also the investments and energy consumption up to which modernization could be considered cost-effective. By means of representative average values, this method is applied to the now widespread conversion from surface irrigation to drip irrigation in Spain. Two conclusions are drawn. First, modernization may, in some instances, be justified only if more productive crop patterns are implemented. Second, saving water is a cheaper option than using an alternative resource only under certain conditions.     

Communal irrigation systems in South-Eastern Africa: findings on productivity and profitability

Abstract

Significant expansion of irrigated agriculture is planned in Africa, though existing smallholder schemes perform poorly. Research at six schemes in Mozambique, Tanzania and Zimbabwe shows that a range of problems are exacerbated by poor management, with limited market linkages leading to underutilization and a lack of profit. Improving sustainability of these complex systems will require: multiple interventions at different scales; investing in people and institutions as much as hardware; clarity in governments’ objectives for their smallholder irrigation schemes; appropriate business models to enable farmers; and better market linkages.     

引黄灌区不同灌溉方式的引水分沙特性及对渠道冲淤的影响

结合黄河下游引黄和灌区灌溉形式的运行工况,以渠道水流含沙量垂线分布和输沙能力为基础,深入分析了渠道引水分沙的特性及其对渠道冲淤的影响.在没有特殊防沙条件下,引黄含沙量一般小于黄河含沙量,约为黄河含沙量的0.86倍;在引黄灌区内,自流灌溉的支渠引水含沙量略低于或等于干渠含沙量,引沙级配相当或略细,引水灌溉将会增加干渠泥沙淤积.对于提水灌溉,若提水泵站进口布置在干渠平均含沙量水深以下,取水含沙量偏大,引沙偏粗,将会减轻干渠淤积;若把提水泵站布设在于渠中下段,可以通过调节提水泵站的引水量来控制干渠水面比降,减少干渠壅水机会,提高干渠输沙能力.     

浑河灌区灌溉用水的管理

1 浑河闸概况及控制灌溉面积 浑河闸位于辽宁省中部,浑河下游,沈阳市后谟家堡村,距大伙房水库75 km,1960年投入运行,是东北最大的水闸,其枢纽工程由22孔拦河闸、10孔进水闸组成,主要任务是担负浑沙、浑蒲灌区的灌溉用水,其设计灌溉面积为5.88万hm2,每年春季还要给盘锦送压盐水,同时还担负沈阳上游的防汛泄洪任务。     

Hybrid membrane systems for secondary effluent polishing for unrestricted reuse for agricultural irrigation.

Field experiments are in progress for secondary wastewater upgrading for unrestricted utilization for agricultural irrigation. The integrative approach of secondary effluent polishing is based on using a hybrid UltraFiltration (UF) and Reverse Osmosis (RO) membrane pilot system with a capacity of around 1 m3/hr. The UF effluent is used to feed the RO membranes. The RO permeate is subsequently applied for vegetable irrigation. Field results indicate the importance of the UF component in the removal of the organic matter and the pathogens that are still contained in the secondary effluent. Under specific conditions, when the dissolved solids content is relatively low, regarding sanitary and health aspects, the UF effluent can be applied for unrestricted irrigation. During the RO stage most nutrients are removed, allowing application of the effluent without jeopardizing the soil fertility and the aquifers. Preliminary economic assessment indicates that the extra cost for effluent polishing via the UF stage only is in the range of 5 to 15 US cents/m3. The extra cost for the RO stage is also assessed at 10 to 25 US cents/m3. The additional cost depends to a large extent on the quality of the incoming raw secondary effluent and local requirements of the command region.     

Losing the watershed focus: a look at complex community-managed irrigation systems in Bolivia

Water policies tend to misrecognize the complexity of community-managed irrigation systems. This paper focuses on water allocation practices in peasant communities of the Bolivian interandean valleys. These communities manage complex irrigation systems, and tap water from several surface sources, many of them located outside the watershed boundaries, resulting in complex hydro-social networks. Historical claims, organizational capacity, resources availability, and geographical position and infrastructure are identified as the main factors influencing current water allocation. Examining the historical background and context-based conceptualizations of space, place and water system development are crucial to understanding local management practices and to improving water policies.     

Role of irrigation and wastewater reuse: comparison of subsurface irrigation and furrow irrigation.

Two different irrigation systems, subsurface drip irrigation and furrow irrigation, are tested to investigate the level of viral contamination and survival when tertiary effluent is used in arid and semi-arid regions. The effluent was injected with bacteriophages of PRD1 and MS2. A greater number of PRD1 and MS2 were recovered from the lettuce in the subsurface drip-irrigated plots as compared to those in the furrow-irrigated plots. Shallow drip tape installation and preferential water paths through cracks on the soil surface appeared to be the main causes of high viral contamination in subsurface drip irrigation plots, which led to the direct contact of the lettuce stems with the irrigation water which penetrated the soil surface. The water use efficiency of the subsurface drip irrigation system was higher than that of the furrow irrigation system. Thus, subsurface drip irrigation is an efficient irrigation method for vegetable crops in arid and semi-arid regions if viral contamination can be reduced. Deeper installation of drip tapes, frequent irrigations, and timely harvests based on cumulative heat units may further reduce health risks by ensuring viral die-off under various field conditions.