There are diverse techniques available to engineers to solve sedimentation problems in irrigation canals. Each technique is suited to a particular set of circumstances, no one technique can cover all circumstances. Therefore, design methods for each technique have been developed. Methods to enable engineers to predict performance have been included in the design methods.

Much of the work had been on-going under DFID funding prior to this project. The project completed the technical development of the techniques and their packaging as design procedures and/or software.

Two irrigation canal systems were studied to collect field data for verification of a sediment routing model: the Kabul Canal in NWF Province, Pakistan and the Bojili system on the Yellow River, China. Sediment movement through both systems was monitored and the results compared well with predictions from the numerical model.

Where possible the outputs from the project have been made easy to use by engineers. The design methods for canal sediment extractors and sluiced settling basins are available as software packages for PC computers: 'DACSE' and 'DOSSBAS' respectively. The vortex vane sediment excluder is a simpler device that can be designed relatively easily using a Design Procedure presented in report OD 126. Techniques for designing canals to accommodate relatively high sediment loads, together with methods to assess sediment transport in irrigation canals, are provided in another PC software package 'DORC'. All the techniques, including the economic assessment (Output 7), were subsequently brought together in a single software package developed under project R6257.

The project has produced quantitative and field tested design methods for a wide range of sediment control structures. It was the first time that such design methods had been made available to engineers. The methods produced by the project cover: canal sediment extractors, sluiced settling basins and the vortex vane sediment excluder (Outputs 3, 4 and 5 respectively). A method for evaluating the economic benefits of providing sediment control structures has also been produced and tested using engineering and economic data (Output 7).

The design of an intake can have a dominant effect on the quantities and sizes of sediments entering a canal system. A 3D numerical model for predicting sediment exclusion at intakes was developed and verified with field data (Output 6).

A sediment routing model was developed which can be used to predict the effect of sediment control on the irrigation canal system as whole and in particular water deliveries. For example the effect can be predicted of sediment control halting or reversing a long-term decline in service area. The model can also be used to assess the impact of partial sediment control measures, which are less costly to construct but leave a requirement for some long-term maintenance.

The outputs from the project have been achieved. The software, design methods and numerical models produced under the project will assist engineers to:

'Deposition of fine sediments in irrigation canals', P Lawrence, A S Ahmed and J C A Russell, Paper R105, 15th Congress of the International Commission on Irrigation and Drainage, The Hague, 1993.

'DORC User Manual', HR Report

'Design manual for canal sediment extractors', HR Report

'DACSE User Guide', HR Report

'The design of sluiced settling basins: a numerical modelling approach', E Atkinson, Report OD 124, HR Report

'DOSSBAS version 1.0, settling basin design software, user manual', Report OD ITM 52, HR Report

'Vortex vane sediment excluder: field verification of design procedure', E Atkinson, Report OD 126, HR Report

'Measurements at the Kapunga curved channel sediment excluder: final report', E Atkinson, Report OD TN 67, HR Report

'A numerical model for predicting sediment exclusion at intakes', E Atkinson, Report OD 130, HR Report

'Comparison of physical and computer modelling of the Kapunga intake with performance of the prototype', E Atkinson, J D Lawson and P Tosswell, Paper R106, 15th Congress of the International Commission on Irrigation and Drainage, The Hague, 1993.

'A method for evaluating the economic benefit of sediment control in irrigation systems', F Chancellor, P Lawrence and E Atkinson, Report OD TN 81, HR Report

'Software for improved management of sediment in irrigation canals', P Lawrence and J C A Russell, p189, Asian Regional Symposium on Maintenance and Operation of Irrigation/Drainage Schemes for Improved Performance, Beijing, 1994

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