No abstract

The headwaters of the Yangtze River are located on the Qinghai Tibetan Plateau, which is affected by climate change. Here, treamflow trends for Tuotuohe and Zhimenda sub-basins and relations to temperature and precipitation trends during 1961–2015 were investigated. The modified Mann–Kendall trend test, Pettitt test, wavelet analysis, and multivariate correlation analysis was deployed for this purpose. The temperature and precipitation significantly increased for each sub-basin, and the temperature increase was more significant in Tuotuohe sub-basin as compared to the Zhimenda sub-basin. A statistically significant periodicity of 2–4 years was observed for both sub-basins in different time spans. Higher flow periodicities for Tuotuohe and Zhimenda sub-basin were found after 1991 and 2004, respectively, which indicates that these are the change years of trends in streamflows. The influence of temperature on streamflow is more substantial in Tuotuohe sub-basin, which will ultimately impact the melting of glaciers and snowmelt runoff in this sub-basin. Precipitation plays a more critical role in the Zhimenda streamflow. Precipitation and temperature changes in the headwaters of the Yangtze River will change the streamflow variability, which will ultimately impact the hydropower supply and water resources of the Yangtze Basin. This study contributes to the understanding of the dynamics of the hydrological cycle and may lead to better hydrologic system modeling for downstream water resource developments.

No abstract

No abstract

Pakistan is endowed with one of the largest contiguous irrigation systems in the world. Considerable food production per unit area and per unit of water is inevitable to meet present-day needs. The optimal use and effective management of water resources may lead to a significant increase in food production. The present study evaluates two different operational strategies for optimal and economical use of water in a downstream control irrigation system of the Upper Swat Canal in the North West Province (NWFP) of Pakistan. Firstly, the computerized weekly rotational scheduling was determined by using the Crop Based Irrigation Operation (CBIO) software developed by the International Water Management Institute (IWMI). Secondly, the application of CBIO coupled with closing the canals at night was simulated using the Canal Management Model (CanalMan).Maps of the command area and primary data used for simulations were collected from various sources. Maps were digitized using a geographical information system to determine accurate data. It is observed that there is oversupply to the system as compared to the crop water requirements during periods of low demand. Significant savings of irrigation water were found by using CBIO and night-time closure of canals. Copyright # 2008 John Wiley & Sons, Ltd. RÉ SUMÉLe Pakistan est doté de l'un des plus grands systèmes d'irrigation contigu dans le monde. Une importante production alimentaire par unité de surface et par unité d'eau est nécessaire pour répondre aux besoins actuels. Un usage optimal et une gestion efficace des ressources en eau peut conduire à une augmentation significative de la production alimentaire. La présente étude évalue deux types de stratégies opérationnelles pour une utilisation optimale et économique de l'eau dans un système d'irrigation en contrôle par l'aval du canal Upper Swat dans la province du Nord-Ouest du Pakistan. Tout d'abord la rotation hebdomadaire informatisée a été déterminée en utilisant Crop Based Irrigation Operation (CBIO), logiciel développé par l'International Water Management Institute (IWMI). Deuxièmement, l'application de CBIO couplée avec la fermeture des canaux pendant la nuit a été simulée en utilisant Canal Management Model (CanalMan).Les cartes du périmètre et les données primaires utilisées pour les simulations ont été recueillies auprès de différentes sources. Les cartes ont été numérisées en utilisant un système d'information géographique pour déterminer des données précises. Il est observé qu'il ya une suralimentation du système par rapport aux besoins en

Demand-based irrigation systems are operated according to crop water requirements. As crop water requirements remain variable throughout the growing season, the discharges in the canal also vary to meet demands. The irrigation system under study is a demand-based semi-automatic irrigation system, where flows in the main canal are automatically controlled and secondary canals manually operated. The main canal headworks have been equipped with the SCADA system with proportional integral (PI) discharge controllers and the canal itself has been provided with self-regulating AVIS/AVIO downstream control gates for flow regulation in the canal. The secondary canals have manually operated sliding gates, which are opened or closed as per crop water requirements of the command area following a crop-based irrigations operation (CBIO) schedule under which they remain closed for one week after one or several weeks open, depending upon water needs. The flow in the main canal is then automatically adjusted according to the number of open or closed secondary offtakes. These operations result in fluctuating flows in the main canal and if not properly planned can cause serious implications for canal safety and its hydrodynamic performance. The PI discharge controllers regulate discharge releases to the canal in order to satisfy demands. The proper selection of PI coefficients ensures system safety and efficient water delivery. The operation of the secondary canals also plays a key role in defining the performance of the automatic operations. The planned opening and closure of a cluster of offtakes ensures safety of the self-regulating structures and stability of the flows in the main canal. In this paper various options have been tested using hydrodynamic modelling and we found some optimal values of PI coefficients and defined some rules for secondary canal operations to enhance the operational performance and sustainability of downstream-controlled irrigation canals. Copyright © 2011 John Wiley & Sons, Ltd. RÉSUMÉLes systèmes d'irrigation à la demande doivent être capables d'apporter l'eau au moment où la plante en a besoin. Comme les besoins en eau des cultures différent tout au long de la saison de croissance, le débit du canal doit varier pour s'adapter à la demande. Le système sous étude est équipé d'une régulation semi-automatique au sens où le canal principal est équipé d'un contrôle automatique et que les canaux secondaires sont actionnés manuellement. L'ouvrage de tête a été équipé de contrôleurs de débit proportionnels et intégraux (PI) de type SCADA et le contrôle aval est dédié à des vannes auto régulantes de type AVIS / AVIO. Les canaux secondaires sont équipés de modules à masque manoeuvrés selon le calendrier d'irrigation des cultures (CBIO) qui stipule que les modules doivent être fermés pendant une semaine après toute période d'irrigation, qui peut elle-même durer de une à plusieurs semaines après ajustée aux besoins en eau des cultures. Le flux dans le canal principal est alors automatiquement ajusté en...

Abstract. Parallel computing briskly diminishes computation time through simultaneous use of multiple computing resources. In this research, parallel computing techniques have been developed to parallelize a program for obtaining a response of single degree of freedom (SDOF) structure under earthquake loading. The study uses Distributed Memory Processors (DMP) hardware architecture and Message Passing Interface (MPI) compilers directives to parallelize the program. The program is made parallel by domain decomposition. Concurrency in the program is created by dividing the program into two parts to run on different computers, calculating forced response and free response of the first half and the second half. Parallel framework successfully creates concurrency and finds structural responses in significant lesser time than sequential programs.

Hydrographic surveying in reservoirs is a key activity in order to collect data for a variety of purposes like estimation of storage capacity, rate and pattern of sediment deposition, movement of underwater sediment delta and reservoir routing, etc. These parameters play a pivotal role in any planning, management and operation activity of the reservoirs. Traditional approaches to perform hydrographic surveying in Indus Basin are time consuming, laborious, comparatively inaccurate and costly. As water resources are under immense pressure due to a variety of factors, such inefficient methods are not acceptable for efficient water management. In this study, an integrated approach for hydrographic surveying is introduced and evaluated in terms of its efficiency in comparison with the traditional methods of hydrographic surveying. The approach develops an integrated environment of hydrographic surveying comprising human, hardware and software. The process of surveying starts from in-house planning using specialized geo-spatial softwares. Then, on site a combination of computer hardware, echosounder, differential global positioning system (DGPS), survey vessel and survey crew is made. Post-processing is performed after conducting a survey in order to improve quality of data by filtering errors and producing the end product like reservoir underwater terrain, development of reservoir stage-area and stage-storage relationships, etc. The study was applied to Tarbela Reservoir, Pakistan.