No abstract

No abstract

No abstract

Despite the extensive application of check and offtake structures in irrigation canals, their periodic assessment is generally not included in water management plans, especially in Iran. This issue would be more important when there are many problems in water distribution in irrigation projects. In this study the performance and operating status of different hydraulic structures in the Varamin irrigation scheme were evaluated using a precise flowmeter. Results show that Neyrpic modules have an error in range of −8 to 83% and these structures, on average, delivered 22% more water. The discharge coefficient of duckbill weirs has changed considerably as well and they are not able to regulate the water level appropriately, because of ageing and physical destruction. The results showed that to achieve an acceptable performance of Neyrpic modules in this scheme it is essential to perform some physical modifications, such as cleaning and sealing the gates, removing sediment around the gates, replacing old gates and continuous inspection of infrastructure. A series of measurements to estimate water losses during the conveyance process show that the conveyance efficiency for each 1000 m length of main, secondary and tertiary canals are respectively 95.0, 91.5 and 89.3%. Consequently to achieve a suitable water distribution pattern, preventive maintenance should be considered. © 2018 John Wiley & Sons, Ltd.

The performance and operation of irrigation networks can be improved using canal automation. This process requires the application of control systems. At the same time, the PI controller has been employed in different areas of the world. However, its adjustment for the different geometric and hydraulic conditions of canals is still considered a major problem for design. The design parameters of a canal such as bottom slope, roughness coefficient and side slope are among the determining factors of water flow dynamic behaviour. In this study, a distant downstream proportional integral feedback control with decouplers is designed for a base canal. By changing the value of design parameters in this canal, their effects on water flow behaviour and controller tuning were investigated. Canal characteristics were determined through a system identification process, and were also used to tune the controller. To simulate the control algorithms and evaluate their performance, a link of the SOBEK model and MATLAB software were used. To evaluate the performance of a well‐tuned controller during a given operation period, the maximum absolute error, integral of absolute magnitude of error and steady‐state error indicators were used. Generally, the result showed the bottom slope to have the most effect on water flow behaviour and tuning of the control algorithm. The effect of the roughness coefficient on the control algorithm and its performance is also more noticeable than the side slope. Copyright © 2015 John Wiley & Sons, Ltd.

No abstract

No abstract

Evaluation of the hydraulic performance of irrigation structures should be used in proper planning of water distribution and the removal of social tensions at water user level. There are several hydraulic indicators that could be interpreted based on social realities. In this study, besides determination of water distribution and conveyance indicators of the Behbahan irrigation scheme, social status was investigated in relation to them. Accordingly, adequacy, dependability and equity indicators in this scheme are poor. Meanwhile, 54% of water users are not satisfied with the performance of water delivery. Based on the questionnaires, training about water distribution is the main request by water users. In this research with a different view about the evaluation of irrigation schemes, existing problems were described from the social perspective. The adequacy indicator is in good condition upstream of the network, while in downstream it is about 40%. Although the knowledge and awareness of water users upstream and downstream are almost equal, only 50% of downstream water users have a relative desire to participate in water services (68% for upstream water users) and their satisfaction is within 20% (62% for upstream water users). Finally, evaluation of hydraulic indicators will be completed and will solve more problems, by considering the social roots of the results. K E Y W O R D S irrigation services, performance of operation, socio-hydraulic performance, water users' behaviour Résumé L'évaluation des performances hydrauliques des ouvrages d'irrigation serait utilisée pour planifier correctement la distribution de l'eau et éliminer les tensions sociales au niveau des utilisateurs de l'eau. Il existe plusieurs indicateurs hydrauliques qui pourraient être interprétés en fonction des réalités sociales. Dans cette étude, en plus de la détermination des indicateurs de distribution et d'adduction d'eau du projet d'irrigation de Behbahan, le statut social a été étudié par rapport à eux. En conséquence, les indicateurs d'adéquation, de fiabilité et d'équité de ce programme sont médiocres. Pendant ce temps, 54% * Les défis de la distribution de l'eau d'irrigation au point de vue des relations socio-hydrauliques