Performance indicators for irrigation and drainage

This paper summarises the performance indicators currently used in the Research Program on Irrigation Performance (RPIP).Within this Program field data are measured and collected to quantify andtest about 40 multidisciplinary performance indicators. These indicatorscover water delivery, water use efficiency, maintenance, sustainability ofirrigation, environmental aspects, socio-economics and management. Theindicators now are sufficiently mature to be recommended for use inirrigation and drainage performance assessment.     

Controlled water table management as a strategy for reducing salt loads from subsurface drainage under perennial agriculture in semi-arid Australia

Recent community based actions to ensure the sustainability of irrigation and protection of associated ecosystems in the Murrumbidgee Irrigation Area (MIA) of Australia has seen the implementation of a regional Land and Water Management Plan. This aims to improve land and water management within the irrigation area and minimise downstream impacts associated with irrigation. One of the plan objectives is to decrease current salt loads generated from subsurface drainage in perennial horticulture within the area from 20 000 tonnes/year to 17 000 tonnes/year. In order to meet such objectives Controlled Water table Management (CWM) is being investigated as a possible ‘Best Management Practice’, to reduce drainage volumes and salt loads.During 2000–2002 a trial was conducted on a 15 ha subsurface drained vineyard. This compared a traditional unmanaged subsurface drainage system with a controlled drainage system utilizing weirs to maintain water tables and changes in irrigation scheduling to maximize the potential crop use of a shallow water table. Drainage volumes, salt loads and water table elevations throughout the field were monitored to investigate the effects of controlled drainage on drain flows and salt loads.Results from the experiment showed that controlled drainage significantly reduced drainage volumes and salt loads compared to unmanaged systems. However, there were marked increases in soil salinity which will need to be carefully monitored and managed.     

Farm salinity appraisal with water reuse

The need for a better understanding of the interaction between irrigation practices and the elevation and quality of the water table is of paramount importance for developing irrigation management strategies to ameliorate the regional problems of elevated saline water tables in the San Joaquin Valley, California. An area of approximately 3000 ha which includes portions of the Diener Ranch and the adjacent University of California, Westside Research and Extension Center, located south of Five Points in the Westlands Water District on the west side of the San Joaquin Valley was chosen for extensive field measurements. Field work consisted of four main activities namely, field instrumentation, collection of records of field activities, periodic data collection, and analyses of field data. Field measurements of water table carried out during 1994 indicated that the water table elevation was sensitive to the irrigation practices. There was a general increase in the area with a water table close to the surface during the irrigation season, and a return to water table elevations similar to the starting conditions at the end of the season. During the study period, the surface water quality deteriorated more in areas irrigated with reuse water and persisted through the end of the season. Depth averaged electrical conductivity for the study area over 6.5 m decreased between December 1993 and December 1994. Vertical hydraulic gradients in the saturated zone, were found to be an order of magnitude larger than horizontal gradients. The direction of vertical gradients changed, with downward gradients following pre-irrigations and upward gradients later in the season, when crop water requirements increased. Based on the results of the field study, it can be concluded that the irrigation management practices have a direct effect on local water table response as well as on water quality. Therefore, irrigation practices that promote less deep percolation losses may be helpful in controlling the water table rise.     

Predicting effects of drainage water management in Iowa's subsurface drained landscapes

Long-term hydrologic simulations are presented predicting the effects of drainage water management on subsurface drainage, surface runoff and crop production in Iowa's subsurface drained landscapes. The deterministic hydrologic model, DRAINMOD was used to simulate Webster (fine-loamy, mixed, superactive, mesic) soil in a Continuous Corn rotation (WEBS_CC) with different drain depths from 0.75 to 1.20 m and drain spacing from 10 to 50 m in a combination of free and controlled drainage over a weather record of 60 (1945-2004) years. Shallow drainage is defined as drains installed at a drain depth of 0.75 m, and controlled drainage with a drain depth of 1.20 m restricts flow at the drain outlet to maintain a water table at 0.60 m below surface level during the winter (November-March) and summer (June-August) months. These drainage design and management modifications were evaluated against conventional drainage system installed at a drain depth of 1.20 m with free drainage at the drain outlet. The simulation results indicate the potential of a tradeoff between subsurface drainage and surface runoff as a pathway to remove excess water from the system. While a reduction of subsurface drainage may occur through the use of shallow and controlled drainage, these practices may increase surface runoff in Iowa's subsurface drained landscapes. The simulations also indicate that shallow and controlled drainage might increase the excess water stress on crop production, and thereby result in slightly lower relative yields. Field experiments are needed to examine the pathways of water movement, total water balance, and crop production under shallow and controlled drainage in Iowa's subsurface drained landscapes.     

A Framework for Valuing Ecological Services of Irrigation Water – A Case of an Irrigation-Wetland System in Sri Lanka

In many countries, irrigation water is usedfor several purposes other than irrigatingfield crops. In Sri Lanka, irrigationwater from canals, wells, and reservoirs isused for domestic purposes, industry,livestock, and fisheries, and it alsocontributes to sustain the environment. However, policy makers and water managersin irrigation systems only take intoaccount water used for irrigating the fieldcrops and sometimes water used for domesticpurposes. Owing to the failure torecognize the different uses and users ofwater, the water in irrigation systems hasbeen undervalued. This paper presents theenvironmental impact of irrigation and aframework for valuing water for itsmultiple and often competing uses,especially focusing on water uses forecological services, in this case wetlands.The south coastal area of Sri Lanka wasselected as a site for a case study, including2,610 ha of irrigated area and adownstream wetland area of 2,250 ha whichhas five lagoons. This wetland areacombines coastal, marine and freshwaterecosystems in a tropical environment inwhich distinct plant and animal speciescoexist in a delicate balance. All users ofwater and other resources, and theirenvironmental problems were identified. Thispaper discusses the policy and managementimplications of valuing water for competinguses.     

排灌企业货币资金内部控制探讨

分析了排灌企业加强货币资金内部控制的必要性．提出了排灌企业加强货币资金内部控制的目标和主要方法．第一，建立严格的货币资金管理制度，着重对于现金和银行存款日常收支过程中最有可能出现的漏洞提出防范措施．第二，建立严格的岗位分工制度，强调经办货币资金收付的不相容各岗位分离，形成相互牵制．第三，建立严格的授权、审批制度．第四，建立严格的会计电算化内控制度，明确会计主管、系统管理员、凭证录入人员的职责权限．     

Testing and statistical analysis of the performance of a pipe drainage system: A case study in north-eastern Italy

A survey program was carried out from June 1988 to august 1989 in North-eastern Italy in a pipe drainage area of 61 ha in order to verify if the year of installation (one part of the system has been installed in 1984 and another one year later) and the cover material of drains (pipes were covered with cocofibre for 2/5 of their length and without envelope for 3/5) could influence the functioning of the system. Collected data of drain discharge and water table depth were subjected to an elaborate statistical analysis.A methodological approach to determine the sample size (how many measurements of discharge and watertable depth are required, in space and time, from a statistical stand-point) in drainage experiment is proposed. For drainage systems similar to the considered one, a sample size of 10–12 drains and 6–8 observation wells can be recommended in order to obtain a standard error lower than 10–15% of the mean.     

湖北省新滩口泵站装置模型试验研

针对湖北省新滩口泵站钟型流道和28CJ56轴流泵运行振动噪音大、效率低、电机负荷率低等问题，基于全流道数值仿真推荐模型试验方案（簸箕型及钟II型方案），进行泵站装置模型试验。通过对实测结果的分析，进行关于装置运行安全、效率以及工程改造可行性、工程量等方面的比较，最后提出该站更新改造方案。     

淮北平原涝渍兼治的组合排水工程形式

由于淮北平原砂姜黑土区的气候、地形、地貌、水文地质、土壤等多方面原因，致使旱、涝、渍频繁，且涝渍灾害往往是紧密相连，先涝后渍，涝渍相随．造成大面积减产．甚至绝收，旱、涝、渍灾害一直困扰着本区的农业发展。通过试验及调查，从治理涝渍效果、提高农业产量、投入产出等方面进行综合分析，提出了几种适宜于本区的组合排水形式。     

Evaluating the Impact of Irrigation and Drainage Policies on Agricultural Sustainability

Farmers in the Broadview Water District in central Californiahave been improving irrigation practices in response to risingirrigation water prices and reductions in water supply since1989, when incentive policies were first implemented to reducethe volume of subsurface drain water generated in theDistrict. The average salinity of water deliveries hasincreased, over time, as the District has recycled largeamounts of drainage water to achieve regional restrictions ondrainage water discharge. We review irrigation and drainageactivities in Broadview since 1986 with an emphasis on thesustainability of crop production when drainage discharge islimited. Average cotton yields in Broadview have declined inrecent years, both nominally and in comparison with averageyields reported for the large county in which Broadview islocated. Average tomato yields in Broadview have increased inrecent years, but county-wide yields have exceeded Broadviewyields with greater frequency than in the late 1980s. Theseobservations suggest that average crop yields in Broadview maybe starting to reflect the increasing salinity of soil andwater resources, which may be due in part to persistentrestrictions on drainage water discharge.