Structural Analysis of Oil-Spill Booms - Mathematical Modelling and Numerical Simulation of Oil Pollution Problems - page 149

7.4 Full-Scale Experiment of a Floating Boom in a Coastal
Environment
7.4.1 Introduction
We present an experiment carried out during the beginning of November 2009 in the
Elorn estuary located in the Brest Bay, Brittany, France. This experiment of a 210m
long curtain composed of three sections of 70m has followed a previous experiment
in May 2008 in the Harbour of La Rochelle with a 100m long barrier. This first
experiment has permitted to elaborate the experimental protocol and the logistic and
maritime operations. Presently, we will describe essentially the Elorn experiment
and we will refer to the first experiment when necessary.
7.4.2 Materials and Methods
Let us describe the natural site, the floating boom and the instruments used for
measurements.
Elorn Site
The winter season is representative of a real oil-spill incident having higher probabil-
ity to occur in winter for this Atlantic region. The nominal period for measurements
is taken at the mid flooding tide during the afternoons of November 2-6, 2009. Time
of low tide is 11h49 and high tide occurs at 17h47 during November 4. Tide heights
are respectively 1.3 and 7.05m at these times.
The Elorn site at the bottom of the Brest bay has been chosen for two reasons.
The probability of a spill exists in that site with respect to the maritime traffic and
overall activity. The sensitivity of the coast where the boom was installed is very
high considering the presence of the pyrotechnic plan of the French Navy.
The site is a relatively protected area from ocean waves and swell. The existence
of hills parallel to the estuary coasts can create a Venturi effect for wind coming from
the South West direction.
More precisely, the site is located North East in the “Rade de Brest”, and belongs
to the Elorn river estuary, in the vicinity of the maritime access and port named “Le
passage” of the Relecq-Kerhuon city.
The boom position corresponds to a part of the National contingency plan
“ORSEC Maritime” of the department “Finistère”. The Elorn estuarine site used
for the experiment is shown on the following Fig. 7.3 .
The estuary is oriented from South West to North East. The ocean flooding tide
current (i.e., the tide goes up) comes from the South West. The Elorn river flows
from the North East.