Modelling the Impacts of Sea level Rise on Coastal Morphodynamics Chloe Morris1, Tom Coulthard1, Daniel R. Parsons1, Sue Manson2 and Andrew Barkwith3 1 School of Environmental Sciences, University of Hull, Hull, United Kingdom ([email protected]) 2 Environment Agency, Crosskill House, Mill Lane, Beverley, United Kingdom 3 British Geological Survey, Environmental Science Centre, Keyworth, Nottingham, United Kingdom

[email protected] @ChloeMorris_13 Research Aim To understand the evolution of coastal systems. To predict their likely behaviour under SLR. To inform sustainable management and build resilience (e.g SMPs).

© Chloe Morris 2018 Modelling the Impacts of Sea level Rise on Coastal Morphodynamics

The Model

The Experiments

The Results The Model

1D Models 3D Models Coastline Evolution Model

Type of Model: One-line, wave-induced sediment transport model Wave-dominated sandy coastal systems

Spatial Scale 10’s – 100’s kms

Temporal Scale Years to millennia CEM CEM2D

Static beach Dynamic Variable water profile Static water level beach profile level against the topographic profile

(a) (b)

Continental Continental Shoreface slope Dynamic shelf shelf Shoreface slope Coastline Evolution Model 2D Calculate Sediment Flux Input Data (CEM2D) Digital elevation model (5/2) Wave climate Qs = K1Hb cos(φb - θ)sin(φb - θ) Water level (tides/SLR) Sediment Distribution Empirical Breaking WaterAccording to the steepest constant wave angle Shoreline Breaking descent formula orientation wave height

Model Set-Up Sediment Transport Define the location of Transport sediment the coastline (XY) along the XY shoreline Shore (incl. wave shadowing) The Model

The Experiments Model Set-Up Wave Climate 106 x 100m 200 x 100m

High Low Angle Angle Left Right

Shoreline Shape

Water

Land Periodic No Flow Boundary Conditions Conditions Sea Level Rise Globally, coastal beaches have experienced net erosion during the last century due to rising sea levels (IPCC, AR5). 0.28 – 0.98 m rise is predicted by 2100: IPCC AR5 0.9 – 1.9 m rise for UK by 2100: UKCP09, low probability

© Anthony Cliffe, 2018 The Model

The Experiments

The Results Coastal Evolution t = 0 yrs t = 300 t = 600 t = 900

t = 1200 t = 1500 t = 1800 t = 2000

No Sea Level Rise Coastal Evolution: Sea Level Rise t = 0 yrs t = 300 t = 600 t = 900

t = 1200 t = 1500 t = 1800 t = 2000

2m / 100 years Coastal Recession 1

Average Position of the coastline 160 NSLR SLR 150

140

(x100m) 130

120

110

100 Horizontal Horizontal distance fromland -2.25m yr-1 90

80 0 500 1000 1500 2000 Simulated Time (yrs) No Sea Level Rise 2m / 100yr Coastal Profile 2

Slope of Coastal Profile (NSLR) Slope of Coastal Profile (SLR) 1.10 1.10 Beach Slope Beach Slope

Shoreface Slope Shoreface Slope 1.05 1.05

1.00 (%) 1.00 (%)

0.95 0.95

0.90 0.90

Average Average Slope Angle Average Average Slope Angle 0.85 0.85

0.80 0.80 0 200 400 600 800 1000 1200 1400 1600 1800 2000 0 200 400 600 800 1000 1200 1400 1600 1800 2000

Simulated Time (yrs) Simulated Time (yrs)

Water

Beach Shoreface Coastal Profile 2

Slope of Shoreface Profile 1.05 NSLR SLR

Linear (NSLR) Linear (SLR)

1.00

0.95

Slope Slope Angle (%) 0.90 Profile shallows with NO SLR Sediment transport is focused along the shoreline 0.85 that is relatively static, forming a shelf

0.80 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Simulated Time (yrs) Coastal Profile 2

Shallow Short

Steeper Longer Morphological memory? Longshore Migration Rate 3

Rate of Longshore Spit Migration NSLR 60

50 40 NSLR = Quicker

30

Position -

X 20 Migration 10

0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Simulated Time (yrs)

Rate of Longshore Spit Migration SLR 60

50

40

30

Position -

X 20

10

0 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Simulated Time (yrs) Landform Size 4

Volume of the Landform 5.E+09 NSLR SLR

4.E+09

4.E+09

) 3.E+09 3

3.E+09

2.E+09

Size Size oflandforms (m 2.E+09

1.E+09 NSLR = Larger 5.E+08 Landforms

0.E+00 0 200 400 600 800 1000 1200 1400 1600 1800 2000 Simulated Time (yrs) Landform Size 4 No Sea Level Rise

Y-Projection Widest Point 1,700 m 700 m

Neck Width 500 m

Cell Count | 148 Landform Size 4 Sea Level Rise

Widest Point 400 m

Neck Width Y-Projection 100 m 1,500 m

Cell Count | 105 Modelling the Impact of Sea Level Rise of Coastal Morphodynamics Chloe Morris, University of Hull

Coastline Evolution Model 2D (CEM2D)

Model the Response to Inform meso- behaviour of changing scale coastal coastal environmental management systems conditions decisions

[email protected] @ChloeMorris_13