by Nitiraj TOOLSEE, General Manager – Irrigation Authority

 

Agriculture is the dominant use of water at the global level and Mauritius is no exception. At present, about 350 Mm³ of water from rivers, reservoirs and boreholes are utilized annually to irrigate some 21,222 hectares of lands and water appropriation by agriculture is bound to increase as the plan to bring an additional 12,000 hectares under irrigation is implemented over the next decades. Since water is an economic and social good, the relentless demand for this commodity by the domestic, industrial and touristic sectors will follow an upward trend. Under this circumstance, the role of agriculture in managing water resources has become crucial.

An integral approach has been adopted to conserve, mobilize and make judicious use of this precious commodity. It hinges on a four-prong strategy encompassing the physical, social, economical and legal aspects namely:

• Consolidation, mobilization of water resources and adoption of efficient system of irrigation
• Grouping of the planters into Water Users’ Association and training in the use of irrigation equipment
• Application of a sound water tariff
• Reinforcement of the legal framework.

Consolidation, mobilization of water resources and adoption of efficient system of irrigation

The consolidation and upgrading of the transmission systems are established priorities in order to minimize the losses. Unless the feeders to reservoir and irrigation canals are rehabilitated, the agricultural sector will penalize itself by obtaining lesser quantity of water at field level as opposed to water released at source. In this endeavour, it is noteworthy that the Nicolière Feeder Canal which conveys water from Grand River South East to Nicolière Reservoir has been rehabilitated for its entire length of 27 km. The walls of the feeder have been concrete-lined (guniting) and stone-pitched, thus bringing down the losses from an average of 35% to 10 – 12%. In the same context irrigation canals in the North and West (Massilia and La Ferme/Magenta Canals) have been upgraded with prefabricated reinforced concrete sections.

This does not imply that efforts to mobilize water resources has been abandoned. Storage of surface run off, recharge of the aquifers and treatment of effluent water for irrigation are high on the agenda. The operation of the Midlands dam of capacity 25.5 Mm³ to regulate an additional volume of 42 Mm³ gives testimony to our commitment to stock flood flows. Furthermore, the hydro geological study on the existing five aquifers in the island will pave the way for tapping addition water resources from the deep strata. On the other hand, the St Martin Treatment Plant in the West will release annually in the Magenta and La Ferme Canals about 10–12 Mm³ treated effluent which after dilution with raw water will be used for irrigation. The level of treatment will satisfy the norms established under the Environment Protection Act and water quality for irrigation.

It would sound paradoxal to economize every drop of water off-field and waste it on the farm through poor distribution and ineffective application. Out of 21,222 hectares irrigated by different techniques of irrigation (surface, overhead and drip), some 2200 hectares are still being irrigated by surface irrigation. Steps have been taken to improve irrigation on 50% of the areas under this system. However, techniques having efficiency of 85% or more such as the overhead (Centre Pivot and drip) are now rapidly substituting surface irrigation.

Grouping of the planters into Water Users’ Association and training in the use of irrigation equipment

One of the major actions initiated in managing water resources has been the implementation of the Participatory Irrigation Management (PIM) programme whereby the small planters in public irrigation schemes have to group themselves in Water Users’ Association for taking full responsibility of the operation and maintenance of the scheme. This is now a trend adopted world-wide as it is recognized that the physical engineering inputs (dams, pumping stations, pipe networks and irrigation technologies) are not an end in themselves in the water sector. The social engineering input is of prime importance.

It inculcates the sense of ownership in the scheme albeit the fact that assets are owned by the State. The control of water supply by the Water Users’ Association improves water distribution and wipes off to a great extent internal conflicts among the beneficiaries leading to improved water management.

However, prior to transferring responsibility to the Water Users’ Association, proper training should be imparted to the beneficiaries in the use of irrigation equipment including regular and timely maintenance of the system. The basics of irrigation scheduling should be expounded to them.

Needless to say that an enabling environment for the setting up of the Water Users’ Association should be created and necessary backstopping from the State provided in the course of their activities. The role of the beneficiaries in sound water management at field level should excel those of policy makers, engineers and irrigation officers.

Application of a sound water tariff

There is a positive, albeit complex, link between water services for irrigation and food security. The availability of water confers opportunities to individuals and planters’ community to boost production, both in quality and diversity, to satisfy their own needs and also to generate income from surpluses. In agriculture, water is reckoned as an economic and social good.

The prevailing water tariff in Mauritius stands as follows:

• 4 cents per m³ from canal offtake
• 100 cents per m³ for pressurized water;
• 50 cents per m³ for underground water;
• Free abstraction if beneficiary holder of a water-right on river.

It is clear from above than an incoherent approach exists. Water from canal offtake is in general being used for surface irrigation or wild flooding which is an inefficient method of irrigation in the local context given the high infiltration rate of the soil. The water demand by this method is augmented by 2.0 – 2.5 times and the tariff is insignificant as compared to other abstractions.

Hence there is an urgency to rationalize water tariff for irrigation. The water tariff should be such as to motivate planters to invest in irrigation and maintain operation as a result of an attractive marginal profit. In no way should it stand as a deterrent. Concurrently, the concept that water is a God-given gift should be erased. In a mixed economy, water should have a price. In order to inculcate the sense of responsibility and discipline, the tariff should penalize users adopting inefficient system of irrigation and those over-exploiting the aquifers.

The exercise is complex as the right balance has to be struck by the State which has to determine the tariff after making massive investment in water mobilization. Consequently cost recovery emerges as an important aspect. In agriculture, the social setting cannot be overlooked. In a nutshell, cost recovery should aim at economic and social profitability.

The water sector is enshrouded by two main Acts namely:

(a) the River and Canal Act of 1863;

(b) the Ground Water Act of 1970.

Minor amendments have been brought to them but in the gist not much change has resulted. Apart from competition for water from other sectors, demands from planters for water rights on rivers and licences to drill boreholes are on the increase. Also due to pollution by industries, the volume of water for agriculture is threatened to diminish. These few issues cited, amongst others, warrant a new legal framework whereby water rights on rivers, pumping from aquifers and protection of our rivers and aquifers be addressed.

The implementation of the Sugar Sector Strategic Plan has released agricultural lands under Voluntary Retirement Scheme (VRS) and Integrated Resort Scheme (IRS). In some cases, lands being irrigated have been converted. Water rights form part and parcel of lands and it would be normal to retrieve the water rights in proportion to the extent of lands foregone in order to safeguard and promote the interest of agriculture.

A compilation of all the water rights on river with full bio-data is under preparation so as to generate the necessary tools for a thorough review. In the same pace, boreholes meant for agriculture are being mapped within the zone of each aquifer following the hydrogeological study carried out by the Ministry of Public Utilities. The objective is to chalk out a strategy to check over-pumping and exploit untapped resources within each aquifer.

Amendments to the Ground Water Act in 1996 to impose penalty rates for volume pumped over and above the monthly quantity allocated was a laudable move to discourage defaulters. As far as the protection of environment is concerned, much headway has been made in legislation by the promulgation of the Environment Protection Act and water quality for irrigation. It is now imperative to make enforcement more aggressive.

CONCLUSION