Coastal Squeeze of Tidal Marshes

Climate change is causing sea levels to rise

Sea level (c

m)

Published studies of sea level rise

How will rising sea levels affect salt marshes?

Image sources: http://www.landscapeinstitute.org/casestudies/casestudy.php?id=73

http://www.climatechange.gov.au/climate-change/australias-coasts-and-climate-change/understanding-the-risk/natural-environments/fs-risks-to-coastal-

environment.aspx;

What is coastal squeeze?

Do marshes have sufficient expansion in the upland?

What will happen to salt marshes under coastal squeeze?

Analysis of remotely sensed data

Digital Elevation Model Multispectral Imagery

Slope Imperviousness

Eureka! Models for measuring coastal squeeze

1

2

3

Salt marshes may move into steep slopes and developed lands

Salt marsh edge expansion into steep slopes (A) and

developed lands (B)

The threat of coastal squeeze increased with sea level rise

0.5 m 1 m

1.5 m 2 m 2.5 m

% C

oas

tal S

qu

eez

e

(in

cre

asin

g th

reat

)

0-20

20-40

40-60

60-80

80-100

Salt marsh area under coastal squeeze decreased

0.5 1 1.5 2.0

Year 2100 sea levels (in meters)

Projected distribution of salt marsh areas

Conclusion

Models to measure coastal squeeze were developed

and tested

The threat of coastal squeeze increases with sea

level rise

Seaward marsh edges are most susceptible to

drowning from coastal squeeze

Moving development away from the tidal floodplain

or designing ecological land use are some of the

ways to protect tidal wetlands from coastal squeeze