Agriculture Fact Sheet: Water diversion structure and irrigation system rehabilitation at the Rivière Grise (2015)


For more than five years, Feed the Future West/WINNER (FTF West/WINNER) has worked to identify opportunities to improve irrigation water access sustainably, while reducing the risk of floods and increasing agricultural productivity. At the Rivière Grise in the Cul-de-Sac corridor, FtF West/WINNER has constructed a water diversion structure to provide permanent water to up to 8,500 hectares of agricultural land, while limiting water levels to prevent flooding. The project has also rehabilitated several irrigation canals within the system and installed gates to control water distribution. Water distribution will be managed by the water user association AIRG, which collects user fees toward the regular maintenance of the irrigation system. Thanks to these investments, irrigation water will be provided to 10,000 farmers who will be able to grow at least two crops per year with a net income of $2,500 per hectare. This represents annual earnings of approximately $20 million for farmers of the Rivière Grise irrigation system.

Objectives of FtF West/WINNER

FtF West/WINNER’s overall objective is to improve the livelihoods of those living within targeted corridors, such as Cul-de-Sac and the Matheux, by promoting sustainable agricultural development. The project works toward three intermediate results: increased agricultural productivity, improved watershed stability, and strengthened agricultural markets.

Project Details

The primary component of the Rivière Grise project is the 450-meter water diversion structure that crosses the river diagonally toward the intake structure. Made out of 9-12 meter long steel sheet piles driven into the ground, the structure permanently diverts water from the river into the irrigation system at a rate of up to 10 m3 per second.
Upstream from the water diversion structure, eight sheet-pile spur beams on both river banks guide river flow direction, reduce erosion, and protect the water diversion and gate structures. In addition, gabion walls stabilize the river banks, which had previously been continually eroded after heavy rains like those from Tropical Storm Sandy.
From the diversion structure, water from the river then flows toward the intake structure, which controls water access within the irrigation system with two manually operated large gates. In the event of heavy rainfall, the gates can close and divert water back into the river, preventing flooding along the irrigation system. 
Downstream from the intake structure, a concrete basin within the canal limits sediment from entering the irrigation system.  Stone masonry along the canal toward the Dumay Bridge assists in water flow and reduces erosion, while a spillway structure helps control water levels in the canal. There is also a pipe to help irrigate an additional five hectares on the left bank of the primary irrigation canal. 
Past the Dumay Bridge, 200 meters of primary canals and 2,130 secondary canals have been rehabilitated in stone masonry within the Rivière Grise irrigation system. This was accompanied by the installation of 38 irrigation gates to help manage water distribution within the system. AIRG will use the irrigation gates to deviate water according to an established water distribution schedule.

Additional Project Information

Budget for the water diversion structure (construction and supervision): $8,300,000
Budget for the irrigation system rehabilitation (construction and supervision): $600,000
Duration: 8 months
Partners: Ministry of Agriculture, Natural Resources, and Rural Development (MARNDR); Ministry of Environment, Associations des Irrigants de la Rivière Grise (AIRG)