Sedimentation Study of Peligre Reservoir, Haiti

Client: Inter-American Development Bank, Washington, D.C.

Contract Period: 2008

Peligre dam and reservoir regulates approximately 6,480 km2 of the Artibonite River watershed. The project was constructed in 1956 to supply irrigation water and control flooding in the downstream Artibonite Valley. In 1971 a 30 MW hydropower plant was installed, which comprises the principal source of electric power in Haiti. By 2008 the reservoir had lost approximately half of its capacity to sedimentation. It was desired to survey the reservoir to confirm the current capacity, and to determine whether it would be possible to operate the hydropower plant for at least 30 more years.

Bathymetric survey. We performed a bathymetric survey combining both boat and land survey techniques, because the reservoir was at a low level at the time designated for the survey. Sediment samples were also collected. This survey confirmed that the loss of reservoir storage was continuing in accordance with the historical trend, and also documented the continued advance of the delta toward the dam. These survey data were used as the basis for calibration of a sediment transport model.

Modeling of sediment transport , energy production and irrigation supply. A sediment transport model was constructed with the Bureau of Reclamation’s SRH-1D software, calibrated with the bathymetric data, and run for a period of 100 years to simulate alternative operating rules and management scenarios for the reservoir. With the assistance of this modeling we developed a long-term operating strategy for sediment management to retard the advance of sediment toward the intake and sustain the project in operation. We also prepared a daily hydrologic behavior model to simulate both power production and irrigation deliveries, investigating a variety of operating rules and computing the power production and reliability of irrigation supply under each alternative. Using the two modeling approaches together we developed an operating strategy which, by incorporating limited flushing, would allow the hydropower facility to continue operating for the next 100 years with little reduction in power production.

Intake reconfiguration. The power intake is located at a low level at the dam, and power generation cannot be sustained using this intake configuration under conditions of advanced sedimentation. We provided schematic designs for modifications to the intake structure which would allow it to continue in operation once sedimentation became more advanced.