Geographic extent of an oil pollution in a river

Comparison of river discharge between major river systems in the world :

• Logone/Chari : 4000 cubic meters/sec in flood
• Mississipi : Normal state, 682000 cfs or 20000 cubic m/s
• Rhine river : 1000 cubic m/s in Bale, 2200 cubic m/s at river mouth
• Mekong : Normal conditions, 15000 cubic m/s and flood, 60000 cubic m/s
• Red River (Hanoi) : Normal conditions, 3300 cubic m/s to flood, 37800 cubic m/s.

Following a spill of potentially toxic material into a river, rapid management decisions must be made in order to protect human health and safeguard threatened resources. Often, municipal and industrial water intakes must be shut down during spill passage. Water storage for drinking and fire protection are limited. Water control structures may also need to be operated, or other protective measures taken to avoid or minimize damage to resources, plant and animal communities, and ecosystems. In support of this decision making, knowledge of the time of arrival and time of passage of water-borne contaminants is vital.

We are using the R-TOT (River Time of Travel) Model from the University of South-Western Louisiana.

It uses a stream flow relationship to predict leading edge, peak, and trailing edge velocity at any river mile location, and integrates velocity through the stream reach for travel time estimates. It is based on an extension of the unit-concentration concept, peak concentration at a downstream river mile location is predicted from stream flow, predicted duration, and mass of spilled material.

Cost of oil spillage

Comparison between some pollution events :

• Exxon Valdez – 260 000 barrels – Total cost : $ 900 Millions over 10 years
• Shell Nigeria 1 – 36 000 barrels
• Shell Nigeria 2 – 5 000 barrels in river
• San Jacinto spill – 3 500 barrels – Total cost : $ 23 Millions

In the case of the San Jacinto oil spill, a meandering river cut straight through one of its established banks short cutting a bend. So it is on assumed firm land that pipeline was cut !