Risks of pollution from the Lom Pangar reservoir

Thematic

Similar project

Risks of pollution from the Lom Pangar reservoir

An assessment of risks associated with the accidental spillage of hydrocarbons into the Lom Pangar dam reservoir in Cameroon.

Projet : 

The Chad-Cameroon pipeline crosses the future Lom Pangar dam reservoir, at the river Lom and the Mbitel tributary along a cumulative length of about 4.7kms.
The objective of the study is to provide a clear and pragmatic definition of the risks and solutions to implement in the case of an accidental spillage of oil into the reservoir:

  • Definition of study scenarios (duration and leakage rate or pipeline rupture, type of hydrocarbon, hydrological conditions, winds)
  • Modelling of the spread of the oil slick in the reservoir and locating potentially affected areas
  • Proposals to adapt the Specialised Intervention Plan in the case of accidental spillage of hydrocarbons from the pipeline, definition of measures to include in the pipeline’s environmental Management Plan and in the dam’s Social and Environmental Plan and a cost estimate of complementary measures.
     
Mission : 

Spill simulations in the reservoir were carried-out using 2D hydraulic modeling with Rubar 20 software for three situations of reservoir level, dam inflow and spill flow. Hydrodynamic conditions were coupled with a model of the spread of the hydrocarbon (GNOME software), taking into consideration the wind, the swell, air and water temperatures, suspended matter, evapotranspiration, as well as the properties of the hydrocarbon (temperature, density, buoyancy and viscosity, composition, pressure in the pipeline and compressibility) and their estimated evolution using ADIOS software.

Two types of hydrocarbon spillages were studied: an undetected leak and a sudden rupture in the pipeline. Hydrographs of spilled hydrocarbons were estimated from the volume between blocked valves and from the calculation of pressure loss.

In the end, 12 spillage scenarios were studied (three hydrological situations, two rupture positions, two types of accidents) as well as five sensitivity tests on flow conditions (Strickler coefficient) or wind conditions.

The results of the study of the spread are notably on the estimation of time of arrival of the hydrocarbon spill to the dam and the identification of stranding zones of the spill along the banks.

Depending on these results, adjustments to the Special Intervention Plan, the Environmental Management Plan and the Dam Environmental and Social Plan in the case of accidental spillage of hydrocarbons from the pipeline are proposed. They include different types of measures:

  • Measures to monitor and intervene in the case of the accidental spillage of hydrocarbons
  • Measures to protect the local population, drinking water and livestock watering
  • Measures related to fishing activity
  • Measures related to animal and plant life and protected species
  • Measures for the monitoring and technical management of the dam
Le projet
Pays/région : 
Cameroun
Client: 
Ministère de l’Energie et de l’Eau
Période : 
2008
Partenaires : 
Oréade-Brèche