The larger the scheme, the more important the need for formalised maintenance planning procedures, so as to use limited budgets in the most effective way. It was aimed to base field work on a medium-sized scheme of some 20,000 ha in an arid/semi-arid region. However, in view of the interest of the Sri Lankan Irrigation Dept, it was decided to modify the criteria for site selection. The selected scheme at Muruthawela, Hambantota Range is one of the largest (1500 ha) managed by the Irrigation department. It is served by an assured water supply, and was affected by a variety of maintenance problems. It had been earmarked by the authorities for limited upgrading to remove structural constraints to increased irrigation

Maintenance problems were identified; information on management practices and constraints, maintenance activities and expenditures was obtained. Condition monitoring procedures were formulated, based on standardised asset condition questionnaire forms adapted for conditions in Sri Lanka. The work formed the basis for Output 2, Guidelines for monitoring system condition.

The MARLIN (Maintenance and Rehabilitation of Irrigation Networks) software was developed as a general tool for asset management. After review by the divisional O&M engineer during a working visit to Wallingford, it was installed at the divisional irrigation offices.

The final project report (OD/TN 94), incorporating the Guidelines for monitoring system condition, was issued in June 1998.

The MARLIN program was developed to select the most urgent priorities for work using three criteria: 1) field assessment of condition; 2) importance: a measure of a component's function and cost relative to other components 3) the economic value linked to its correct functioning - irrigated area was chosen as a proxy parameter.

Discussions with O&M engineers showed that the Muruthawela scheme was only a part of their overall concerns. A large number of adjacent so-called annicut schemes (traditional schemes drawing their water from upgraded weirs on perennial rivers) also come under their jurisdiction. Many of these schemes are affected by deteriorating control gates and downstream erosion damage. The MARLIN procedure and program were therefore extended to allow work priorities to be assigned to annicut structures outside the main irrigated area.

The resources assigned to maintenance are so scarce in Sri Lanka, that annual maintenance surveys prior to the canal closure period cannot be carried out, unlike the practice on many larger schemes elsewhere. In these circumstances, it is difficult to build up a database of system condition. It was suggested that condition reports could be returned to the project office every time a canal worker undertook some routine work, and in this way information on the whole system could be built up over time. In the different circumstances of Mexico (see below), modulos (farmers' groups managing and maintaining around 10,000 ha each) have a vested interest in maintaining the condition of their system.

MARLIN at present appears most suited to locations where there is a particular focus on maintenance, as a result for example of system turnover to farmers. In Mexico, farmers' groups at present are required by government to spend an agreed percentage of their income on maintenance. There is evidence that the amount is more than adequate to keep the system in good order. Farmers believe that a rational system of defining system condition and needs could help them negotiate a lower budget. The MARLIN procedures were very well-received. There are other nations where governments have instituted sweeping programmes of turnover to farmers, where MARLIN would be applicable.

G. Cornish IISPM: Aids to Maintenance. Report OD/TN 94. HR Report. (1998)

J. Skutsch Improved Irrigation System Planning and Management. Article in (1998) Water. HR Report.

Many requests for information have been received and dealt with as a result of articles in the Water Newsletter, and ICE's Research Focus.

In February 1998, with additional support from DFID, HR undertook a collaboration with IWMI on a project in Mexico to improve identification of maintenance works on schemes in Mexico turned over to farmers. A Spanish language version of MARLIN was installed in the project area.

The project was presented at a Research Day promoted by the British National Committee of ICID Wallingford in March 1999.

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