14 September 2019 | New Scientist | 29Against the flow
Photographer Drew Angerer
Agency GettyTHIS 930-square-metre model may
help save the fragile Mississippi
delta and coastal ecosystem.
Researchers at the Louisiana State
University Center for River Studies
in Baton Rouge use it to mimic
320 kilometres of the lower
Mississippi river as it winds its way
to the Gulf of Mexico, simulating
a year of movement in an hour.
The Louisiana coastline has
one of the world’s highest rates
of relative sea level rise. Since
the 1930s, Louisiana has lost more
than 5000 square kilometres of
wetlands through subsidence and
the increased effects of climate
change. Now, an area of coastal
land the size of an American
football field disappears every
90 minutes.
The delta is built from sediment
that washes down the river,
but the construction of levees to
prevent flooding means much of
this sediment ends up in the sea.
The state plans to divert river
sediment into eroding wetlands
to rebuild land. One terracing
project (shown below) has already
converted open water into new
marshlands near Fort St Phillip.
Water and granules can be put
into the model to simulate the
movement of sediment. The
model will help work out how
single or multiple diversions
affect the river’s flow. ❚Donna LuEngineering the future
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