Towards a Sustainable Coast - umaine.edu
Transcript of Towards a Sustainable Coast - umaine.edu
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!