Towards a Sustainable Coast

• A storm packing winds of up to 130 miles per hour has hit Japan. Surging waves hit against the breakwater in Udono in a port town of Kiho, Mie Prefecture, Japan. A powerful typhoon is bearing down on Japan's tsunami-ravaged northeastern coast, approaching a nuclear power plant crippled in that disaster and prompting calls for the evacuation of more than a million people.

Typhoon Roke hits Japan

Coastal Flood at Brighton (Jan 2007)

Fundamental understanding of physical processes relevant to practical coastal and offshore engineering and design problems

Research Goal

Turbulent boundary layers Wave, tide and current hydrodynamics in the coastal region Coastal flooding and erosion during extreme events Marine renewable energy Wave and fluid interactions with fixed and floating structure Sediment transport Air-sea interactions

Research Interest

Ensemble Prediction of Inundation Risk and Uncertainty arising from Scour (EPIRUS) Research teams:

University of Plymouth (Leader) University of Swansea University of Bristol Collaborators: Proudman Oceanographic Laboratories Halcrow Group New Forest District Council

Principle Investigator : Qingping Zou Yongping Chen, Ian Cluckie, Dawei Han,

Richard Hewston, Xin Lv, Shunqi Pan, Zhong Peng, Dominic Reeve

Coastal Flood and Erosion

• £132 billion assets at coastal flood risk

• £7.8 billion assets at coastal erosion risk

• 4 million people and properties in England and Wales at coastal flooding and erosion risk

Coastal Erosion at Happisburgh (July 2006)

Coastal Flood at Brighton (Jan 2007)

After Nicholls et al (2007)

Top 20 Cities Exposed to Coastal Flooding

After Nicholls et al (2007)

Top 20 Cities Exposed to Coastal Flooding

Socio-economic: population, economic growth and urbanization

New Orleans Flooding 2005 (Hurricane Katrina) • $21 billion cost

• 169 miles of levee damaged

– Overtopping – Breaching – scour

• 714 death toll • 80% of the city flooded

Coastal Flood Defence Failure • Functional failure:

Conditions exceed what the defence was designed for

• Structural failure: Element or components of defence fail

to perform as expected – Wave overtopping

Erosion of the back and crest of defence

Damage to armour layers – Toe scour

Leads to beach lowering

Increase water depth

Larger waves

More beach lowering Undermining defence

Toe scour

Wave overtopping

Objectives To improve the capacity for predicting coastal

flood risk due to extreme events and estimate the associated uncertainty

To assess the propagation of uncertainty from meteorological forecasts to coastal flood risk predictions Approach

A “clouds-to-coast”, integrated modelling framework for ensemble prediction of coastal flood risk arising from overtopping and scour

“Clouds-to-coast” Ensemble Modelling Framework of Coastal Flood Risk

1. Weather forecasting

model 2. Tide, surge & wave

models 3. Surf zone models

Conclusions-Tide, Surge and Wave • Ensemble results are sensitive to the initial date • The accuracy of the predictions of waves and surge

can be significantly improved by using ensemble approach closer to the storm events.

• For storm peaks, the accuracy of T+2 day ensemble results is better than that of control case (analysis & T+6 hr forecasts)

• Significant uncertainty associated with wave and surge

• Ensemble predictions outperform deterministic models in T+x days forecasts

Conclusions-Surf Zone model Overtopping predictions in good agreement

with published data Ensemble mean overtopping discharge

follows Weibull distribution Important to include uncertainty with

predictions Uncertainty for overtopping and nearshore

wave predictions are larger than those of offshore wave predictions

Scour tends to increase overtopping in the same fashion as high tide

£28 Million Wave Hub Project -To create one of the world’s largest wave farms for demonstration and testing wave energy converter devices

• UK Wave Energy

The Wave Hub Project Funded by SWRDA/EU To quantify resources

characterisation To understand the

interaction between waves and WECs

To predict the impacts of WECs on adjacent coastlines and beaches

To assess impacts of climate change

Wave Hub

A two phase flow level set model -Wave energy device performance -Survivability in extreme storm

Wind fields provided from the Global Forecast System model to WaveWatchIII

Tide elevations and tidal currents by the OTPS/TPXO Tide Model Driver to ROMS model

Nested grids of SWAN model

Wave Watch III (wave parameters)

The modelling system

ROMS model two-way coupled system

Wave-tide interactions at the Wave Hub site

Effects of Wave Farm on Wave Height

The energy transmission percentage was set as 75% which represents an array of densely spaced, high-efficiency WECs

Effects of Wave Farm on Sediment Transport

Currents (m/s)

EU project: Loads on entrance platforms for offshore wind turbines

• Loads on entrance platforms for offshore wind

turbinesUK Wave Energy

Coastal flooding and erosion due to extreme event

Marine renewable energy devices and their environmental impacts

Flow and wave interactions with fixed and floating offshore structures and adjacent sea bed

Interactions of coastal ocean with adjacent river estuary

Transport of biological and geochemical material by waves and currents and turbulence in the coastal region

Impacts of climate change on coastal storm risk and mitigation

Future Vision and Plan

“The shore is an ancient world, for as long as there has been an earth and sea there has been this space of the meeting of land and water…. Each time that I enter it, I gain some new awareness of its beauty and its deeper meanings” by Rachel Carson (1959)

Thank you for your attention!