To develop methodologies for improving the performance of small irrigation schemes.

Output

1. Guidelines to assist in selecting designs appropriate to local conditions in Africa.
2. Software and manual for detailed design of small surface- irrigated schemes.
3. Software and manual for design of hydraulic drop structures.
4. Recommendations for operation and design of low pressure irrigation pipelines for small farmers.

Output 1 : Guidelines for designing and developing small schemes based on technical and socio-economic field investigations. Reference to ten small schemes, mostly farmer-managed, in Kenya, two previous investigations in Zimbabwe, and an action programme at a low pressure pipeline project in Egypt.

Output 2 : The MIDAS (Modular Irrigation Design Aid Software) program was developed complete with manual and tutorial. Training courses for local designers were held in Kenya (2) and Tanzania. The software was handed over to the Irrigation & Drainage Board and SISDO in Kenya, also to the Irrigation Department in Tanzania.

Output 3 : The DROP program and manual for analysis and design of energy-dissipating structures was produced under a collaborative programme of software development with ILRI (Netherlands) and Catholic University of Leuven (Belgium).

Output 4 : The investigation of the low pressure pipeline system at Mansouria, Egypt gave rise to Guidelines and recommendations for system design and development.

1 Guidelines

Increasingly, Governments wish to reduce their financial involvement with irrigation. The Kenyan model of scheme management by farmers under a form of contract with government appears to be fairly successful and sustainable. Overall, ten of 13 schemes were sustainable, though a number received substantial government support. On a few schemes, farmers' income from agriculture did not fully cover the true economic costs yet they continued to farm. In the better schemes, farmers were successfully marketing their produce to the European Community via intermediaries.

Systems suitable to management by small farmers differ in a number of respects from textbook designs. Systems which are simple to operate offer the best chance for farmers to reach practical compromises in water distribution.

Many of the schemes were intermittently, or frequently, short of water. Farmers are skilled in adjusting cropped area to expected supply but the area actually cropped frequently fell short of the nominal area. River basin planning is urgently needed to avoid conflicts in development. When the supply was sufficient for the area cropped, overall efficiency on farmer-managed schemes was found to be 40-45%. The figure is comparable with the performance of small, centrally managed schemes which must carry heavy management overheads, and higher than the values for many large schemes (30-40% efficiency or less). The output of the better schemes is sufficient that farmers can respond to water shortages by introducing low pressure, locally-made sprinkler systems. The water use performance of the equipment is substantially better than surface irrigation, though not up to the standards of commercial farming. The sprinklers are robust, can be maintained by farmers, and represent a successful strategy for growing higher value crops.

System maintenance is not well carried out on the farmer-managed schemes. Shortage of labour and the demands of other community activities can delay irrigations and reduce output. Despite severe constraints on funding, central management tends to manage maintenance better.

Farmers, of whom at least 50% tend to be women, may lack ready access to credit. Credit on reasonable terms is essential to maximise returns from land.

2 The MIDAS programme was used successfully by developing country designers involved with extensive programmes of small scheme developments. Users must commit themselves to a period of intensive initial training. Progress is set back when trained users are transferred, or leave for more profitable employment in the private sector.

3 The low pressure pipeline at Mansouria, Egypt, was viewed by government as a successful pilot study, demonstrating the potential, costs and constraints inherent in introducing a relatively sophisticated technology, developed for larger farmers, to small farms. The systems operate most successfully when serving a few farmers taking their water in sequence. Management overheads, and the potential for disputes, increase when large numbers of farmers have to agree complex systems of rotation to share the water.

FM Chancellor (1997) Smallholder irrigation: Ways Forward. Guidelines for JM Hide appropriate scheme design.(2 volumes). OD 136. HR Report.

Volume 2 of the Guidelines summarises the results of performance studies on 13 small schemes in Zimbabwe, Kenya and Egypt. Some 20 individual scheme reports detail the performance investigations.

JM Hide (1996) MIDAS: Modular irrigation design aid software. User manual. HR Report.

JM Hide (1996) MIDAS. Tutorial. HR Report.

RD Hinton, (1997)   The performance of a low pressure irrigation pipeline, El
DED El Quosy et al. Hammami, Egypt. Implications for design and management. Report OD/TN92. HR Report.

J C Skutsch (1997) DROP-Design Manual. Report OD/TN86. HR Report.

The project has been publicised on the IPTRID network and the Water newsletter.

1 Results were disseminated and discussed with participants from 10 sub-Saharan nations at a DFID-funded Workshop in Nairobi in 1996. The guidelines have been placed on CD ROM for dissemination by FAO.

2 MIDAS was extended, adapted, and subsequently used by international consultants in Indonesia and Ghana.

3 DROP has received favourable response from consultants and is earmarked for dissemination in University courses.

4 Egyptian government policy for application of pipelines in New Land areas has absorbed the project findings.

Zimbabawe : Agritex
Kenya : Irrigation and Drainage Board, MOA, with Dutch government support, and SISDO (an NGO)
Egypt : WMISRI, Water Research Centre.

Tel: +44 1491 835381
Fax: +44 1491 826352
Email: dfid-kar-water@hrwallingford.co.uk