IMPROVING ON-FARM IRRIGATION SCHEDULING

KEY CHALLENGES

The Food and Agricultural Organisation (FAO) Project "Strengthening Agricultural Water Efficiency and Productivity on the African and Global Level" aims to strengthen agricultural water management practices in selected places in Africa. One of the project's focal country is Uganda where an approximate 70'000 ha are currently irrigated. Despite the fact that the government of Uganda is heavily investing in irrigation infrastructure, there were so far no comprehensive studies to assess water use efficiency in existing irrigation schemes, even though it is well known that irrigation schemes are operating far below their potential.

NEEDS

The Mubuku irrigation scheme is located upstream from Lake George in Western Uganda and is fed by runoff from the Sebwe River that emerges on the eastern slopes of the Rwenzori mountains. The irrigation scheme was planned and constructed in the sixties and built in two phases. Phase 1 is a pressurised pipe system whereas Phase 2 is a canal system. The system covers roughly 556 hectares and is divided into a set of 13 divisions/blocks where approx. 160 are cultivating crops and vegetables. Each block is fed by a lateral canal where average farm holding sizes are 3.2 hectare.

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Water guards are in charge of ensuring that irrigation water is distributed according to the schedule. However, the three guards commissioned to perform these distribution/control tasks on a daily basis nowadays cannot cover the whole area reliably and would need labor reinforcement for being able to correctly perform their tasks. This, among other things, leaves room for improvements in irrigation on the scheme, among and between the blocks and plots respectively.

IMPLEMENTATION

Hydrosolutions Ltd. started to work with FAO and the National Agricultural Research Organization (NARO) in the Mubuku Irrigation scheme for testing the discharge.ch measurement technology in operational use for helping to improve irrigation water management practices.The Discharge App was used to collect daily discharge data which were compared to calibrated weirs and used as input data for the FAO MASSCOTE approach  and water productivity assessments. A Water Balance for Phase 2 Canal in Mubuku scheme was established at main canal and lateral levels based on crowd-sensed measurements.​

RESULTS

The collected data provided further insights about the following questions:

• How does precipitation drive availability of irrigation water in the scheme?

• How can the daily data be used for water balance assessments?

• How can the data be used for irrigations schedule assessments?

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Measuring intake flows into the scheme is important from the overall water balance perspective but also relevant for irrigation water pricing and the considerations of sustainability in the larger catchment.

The comparison of sub-division canal flow measurements and water balances showed that compliance with the existing fixed rotation irrigation schedule is modest. this points to the fact that informal arrangements are present that are not reflected in the communities' 'agreed-upon' official schedule.

To summarize, Mubuku Scheme provides an opportunity to demonstrate optimized irrigation water use and maximized efficiency through the use of the discharge.ch platform technology. All local stakeholders are interested in the technology and are eager to obtain good and consistent measurements to demonstrate the utility of having data when it comes to optimizing agricultural schemes. The constant use of the iMoMo Discharge App in the field in Mubuku irrigation Scheme for more than half a year and the feedback received from the field during this campaign (and, for that, in all other ongoing measurement campaigns in Eastern Africa, Central Asia and Europe), helped to further improve robustness of the technology as well as its usability due to constant software updates and improvements.

The Ministry of Agriculture in Uganda has expressed its strong interest in the discharge.ch technology once the operational reliability and precision (i.e. validity of results) has been demonstrated. They acknowledge that one key advantage of the use of the discharge.ch platform for on-farm and off-farm measurements is that it is an integrated technology that provides first a robust data acquisition technology of digital discharge data thus minimizing errors in relation to handling and transcribing analog data (i.e. data that was measured with a propeller and noted down in a notebook etc.). Furthermore, all measurements come with proof images that help to assess the quality of a particular measurement on the one hand and allow to monitor the performance of a crowd-sender in an easy and remote way on the other. Finally, data management, including exporting data for use in other programs and / or reporting is easy and straightforward.