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Shorelines face growing threats due to climate change and diminishing sand supply. Coastal headlands, common rocky features along coastlines, are crucial in shaping hydrodynamics and sediment transport. Yet, the influence of future climate conditions, including sea-level rise (SLR) and intensified storm energy on complex shorelines with headlands has remained relatively unexplored. In this study, we model changes in hydrodynamics and headland bypassing under different SLR and higher storm wave scenarios. Our findings reveal the formation of circulation cells on both sides of a headland, where wave energy converges around the headland zone. Future climate conditions result in larger storm waves on the beach. However, SLR enhances nearshore currents through a landward shifting of the circulation cells, while higher storm waves intensify offshore flow currents due to the seaward movement of the cells. This effect, in turn, increases the potential for headland sediment bypassing.

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

Coastal boulder deposits (CBD), transported by waves at elevations above sea level and substantial distances inland, are markers for marine incursions. Whether they are tsunami or storm deposits can be difficult to determine, but this is of critical importance because of the role that CBD play in coastal hazard analysis. Equations from seminal work by Nott (1997), here referred to as the Nott Approach, are commonly employed to calculate nominal wave heights from boulder masses as a means to discriminate between emplacement mechanisms. Systematic review shows that this approach is based on assumptions that are not securely founded and that direct relationships cannot be established between boulder measurements and wave heights. A test using an unprecedented dataset of boulders moved by storm waves (with associated sea-state data) shows a lack of agreement between calculations and actual wave heights. The equations return unrealistically large heights, many of which greatly exceed sea states occurring during the boulder-moving storms. This underscores the finding that Nott-Approach wave-height calculations are unreliable. The result is general, because although the field data come from one region (the Aran Islands, Ireland), they represent a wide range of boulder masses and topographic settings and present a valid test of hydrodynamic equations. This analysis demonstrates that Nott Approach equations are incapable of distinguishing storm waves from tsunami transport and that wave heights hindcast from boulder masses are not meaningful. Current hydrodynamic understanding does not permit reliable computation of wave height from boulder measurements. A combination of field, numerical, and experimental approaches is required to quantify relationships between wave power and mass transport onshore. Many CBD interpreted as tsunami deposits based on Nott-Approach analysis may in fact have been emplaced during storms and should therefore be re-evaluated. This is especially imp

A crown wall is a gravity based L- shaped concrete structure on top of a rubble mound breakwater. Functions of a crown wall are: reduction of wave overtopping, enable transport on the breakwater and placement of pipelines on top of the flat surface. Marine contractor Van Oord was awarded to extend a breakwater with a crown wall on top, located in Romania. The design, already made by a local consultant, was reviewed by Van Oord, which led to the conclusion that the crown wall would be blown of the breakwater for that particular design in combination with the design wave conditions. Subsequently, physical scaled model tests were executed by Artelia in Grenoble, but, against all expectations the crown wall appeared to remain stable. Based on the contradiction between stability calculations and the outcome of the scaled model tests, the hypothesis arose that currently used wave load calculation methods lead to designs that seem to be conservative especially when freeboard, the vertical distance between the still water level and the base of the crown wall, increases. An experimental research is carried out in which the effect of freeboard is examined by varying water levels and wave conditions while geometrical properties of the structure remain constant. Tests are divided in three main subjects: pressure measurements, uplift stability and overall stability. Based on pressure measurements it is concluded that the mostly used design method PEDERSEN [1996] and its extended version of NØRGAARD et al. [2013], assume an upward pressure distribution which is too conservative in shape and distance over which pressure is exerted against the base of the crown wall. These methods assume a linear pressure distribution whereas this seems to be conservative based on test results since S-shaped and parabolic upward pressure distributions are found. Furthermore, it is assumed that upward pressure acts over the full length of the base whatever wave conditions and freeboard are. However, Civil Engineering and Geosciences, Hydraulic Engineering

A crown wall is a gravity based L- shaped concrete structure on top of a rubble mound breakwater. Functions of a crown wall are: reduction of wave overtopping, enable transport on the breakwater and placement of pipelines on top of the flat surface. Marine contractor Van Oord was awarded to extend a breakwater with a crown wall on top, located in Romania. The design, already made by a local consultant, was reviewed by Van Oord, which led to the conclusion that the crown wall would be blown of the breakwater for that particular design in combination with the design wave conditions. Subsequently, physical scaled model tests were executed by Artelia in Grenoble, but, against all expectations the crown wall appeared to remain stable. Based on the contradiction between stability calculations and the outcome of the scaled model tests, the hypothesis arose that currently used wave load calculation methods lead to designs that seem to be conservative especially when freeboard, the vertical distance between the still water level and the base of the crown wall, increases. An experimental research is carried out in which the effect of freeboard is examined by varying water levels and wave conditions while geometrical properties of the structure remain constant. Tests are divided in three main subjects: pressure measurements, uplift stability and overall stability. Based on pressure measurements it is concluded that the mostly used design method PEDERSEN [1996] and its extended version of NØRGAARD et al. [2013], assume an upward pressure distribution which is too conservative in shape and distance over which pressure is exerted against the base of the crown wall. These methods assume a linear pressure distribution whereas this seems to be conservative based on test results since S-shaped and parabolic upward pressure distributions are found. Furthermore, it is assumed that upward pressure acts over the full length of the base whatever wave conditions and freeboard are. However, Civil Engineering and Geosciences, Hydraulic Engineering

The U.S. Army Engineer District, Los Angeles and the Coastal Inlets Research Program have conducted a comprehensive study to investigate wave, flow, sediment transport, and permeable breakwaters with rocky outcrop bottom at Dana Point Harbor, as a part of the harbor revitalization project, on the southern Orange County coast, CA. The 5,500-ft shore-parallel West Breakwater and 2,250-ft shorenormal East Breakwater to protect the harbor are the main interest in the study of the structural integrity and functionality. The field data collection includes 2009 survey of breakwaters, marinas, harbor entrance and surrounding at the harbor, and installation of a pair of ADCPs to measure water levels, waves, and currents inside and outside West Breakwater. The numerical models were used to calculate wave transmission, current and sediment seepage through permeable breakwaters and circulation in the harbor. Permeable breakwaters are simulated by models under wind forcing, tides, bottom friction, and wave reflection. The oceanographic design criteria established previously for the Harbor were updated based on historical storm waves and the present model simulations for 50-yr and 100-yr return periods. The data analysis and model results together provide information to ascertain the action to repair breakwaters and structural alternatives to improve the navigation channel maintenance and tidal flushing in the harbor., The original document contains color images.

On Banneg Island, France, very high water-level events (6.5 m above the astronomical tide) have been observed on the western cliff, exposed to large swells from the North Atlantic. The analysis of hydrodynamic measurements collected during the storm of 10 February 2009 shows unusually high (over 2 m) infragravity wave runup events. By comparing runup observations to measurements in approximately 7 m of water and numerical simulations with a simplified nonlinear model, two distinct infragravity bands may be identified: an 80 s infragravity wave, produced by nonlinear shoaling of the storm swell; and a 300 s wave, trapped on the intertidal platform of the island and generating intermittent, low-frequency inundation. Our analysis shows that the 300 s waves are a key component of the extreme water levels recorded on the island.

On Banneg Island, France, very high water-level events (6.5 m above the astronomical tide) have been observed on the western cliff, exposed to large swells from the North Atlantic. The analysis of hydrodynamic measurements collected during the storm of 10 February 2009 shows unusually high (over 2 m) infragravity wave runup events. By comparing runup observations to measurements in approximately 7 m of water and numerical simulations with a simplified nonlinear model, two distinct infragravity bands may be identified: an 80 s infragravity wave, produced by nonlinear shoaling of the storm swell; and a 300 s wave, trapped on the intertidal platform of the island and generating intermittent, low-frequency inundation. Our analysis shows that the 300 s waves are a key component of the extreme water levels recorded on the island.

On Banneg Island, France, very high water-level events (6.5 m above the astronomical tide) have been observed on the western cliff, exposed to large swells from the North Atlantic. The analysis of hydrodynamic measurements collected during the storm of 10 February 2009 shows unusually high (over 2 m) infragravity wave runup events. By comparing runup observations to measurements in approximately 7 m of water and numerical simulations with a simplified nonlinear model, two distinct infragravity bands may be identified: an 80 s infragravity wave, produced by nonlinear shoaling of the storm swell; and a 300 s wave, trapped on the intertidal platform of the island and generating intermittent, low-frequency inundation. Our analysis shows that the 300 s waves are a key component of the extreme water levels recorded on the island.

A comprehensive numerical modeling study was undertaken to support the barrier island restoration plan as part of the Mississippi Coastal Improvements Program. Hydrodynamic, wave, sediment transport, and water quality numerical modeling was conducted to evaluate the effect of Camille Cut closure on circulation and water quality of Mississippi Sound; the combined effect of Camille Cut and Katrina Cut closures on circulation and water quality of Mississippi Sound; reduction of storm wave energy at the mainland Mississippi coast as a result of closing Camille Cut; and optimization of nearshore placement of sand in the littoral zone. Water quality modeling of Mississippi Sound was conducted to determine potential impacts from proposed actions in the Ship Island area using the Curvilinear Hydrodynamic 3D model (CH3D) and the water quality model (CE-QUAL-ICM). Although water quality changes were observed for the alternatives modeled, the impact of Ship Island degradation or restoration does not significantly alter system wide circulation and water quality conditions. However, the condition of Ship Island has localized effects on circulation and water quality. The changes in storm wave energy at the mainland Mississippi coast as a result of Ship Island degradation and restoration were quantified through the application of an integrated coastal storm modeling system. Results indicate that the closure of Camille Cut and Ship Island restoration have the potential to reduce storm waves at the mainland coast. The C2SHORE model was applied to numerically predict the morphological response and sand fate for a selection of proposed alternatives. Results indicate that the Camille Cut restoration fill survives higher-frequency storms (such as the 1-yr and 10-yr events), but is breached during the lower-frequency 500-yr event modeled., The original document contains color images. Prepared in collaboration with the Environmental Laboratory, US Army Engineer Research and Development Center, Vicksburg, MS and USACE, Jacksonville District, Jacksonville, FL.

Dana Point Harbor is located in the City of Dana Point, midway between Los Angeles and San Diego, along the southern Orange County Coast of California, as depicted in Figure 1-1. The harbor consists of dual protective breakwaters (East and West Breakwaters), two recreational marina basins, a turning basin, two anchorage basins, a boat launch ramp area, a bathing beach, and several shallow-draft navigation channels. The development of Dana Point Harbor was initiated in 1949 and an optimal design plan was later selected after various design alternatives were formulated and evaluated. Construction of the dual breakwaters at Dana Point Harbor commenced in 1963 and was completed in 1968. The harbor operation for boat occupation and recreational purpose began after the completion of channel and basin dredging in 1970. Table 1-1 presents the physical dimension of the dual protective breakwaters as well as various project depths in the channels and basins. At the time of construction, both the East and West Breakwaters were designed as a semi-permeable structure as comprised of multiple layers of riprap stones without an impermeable core layer. The weight of riprap stones in the outer layers range from 6 tons at the landward end to as heavy as 20 tons in the structure head area. Small voids were left intentionally during stone placement to allow currents partially flowing through the breakwaters, thereby promoting better water circulation within the harbor., Prepared in cooperation with Noble Consultants, Inc.

Coastal storm activity for the eastern North Island, between East Cape and Wellington, has been quantified from a meteorological perspective through the use of cyclone tracks and extreme winds and from an oceanographic perspective by using hindcast wave information. It has culminated in the production of a high quality, digital coastal storm database for the eastern North Island. Together, this information provides a new understanding of coastal storm behaviour for the eastern North Island. A regional database of historical coastal storms along the eastern North Island between 1930 and 2005 (75 years) is now available in digital format. Coastal storms were identified as bouts of strong winds (greater than or equal to 10.5 m/s) from long-term local wind records from 1962 to 2005, and prior to this period, coastal storms were qualitatively recognised as any event leading to coastal shipping disruptions/delays, large wave conditions along the coast, episodes of coastal erosion and strong onshore wind periods. This digital database consists of five informative components that include storm meteorology, storm oceanography, impacts and damages, storm photo’s and images, and data sources. It has identified a set of five storm types for the eastern North Island consisting of Trough/Ridges, East Coast Lows, Subtropical Lows, Tasman Sea Lows, and Cyclone-Anticyclone pair. The two dominant types are Trough/Ridge and East Coast Low, with the Trough pattern involving weather systems primarily from the southern ocean, whilst East Coast Lows involve large cyclones off the coast that can be distantly generated (from the Tasman Sea or subtropics) or locally generated around NZ from southern ocean troughs. The most intense coastal storms off the eastern North Island are East Coast Lows involving cyclones from the subtropics. These storm events reveal blocking-type anticyclones east of the Chatham Islands play a vital role in coastal storm activity by steering cyclones southward towar

Coastal storm activity for the eastern North Island, between East Cape and Wellington, has been quantified from a meteorological perspective through the use of cyclone tracks and extreme winds and from an oceanographic perspective by using hindcast wave information. It has culminated in the production of a high quality, digital coastal storm database for the eastern North Island. Together, this information provides a new understanding of coastal storm behaviour for the eastern North Island. A regional database of historical coastal storms along the eastern North Island between 1930 and 2005 (75 years) is now available in digital format. Coastal storms were identified as bouts of strong winds (greater than or equal to 10.5 m/s) from long-term local wind records from 1962 to 2005, and prior to this period, coastal storms were qualitatively recognised as any event leading to coastal shipping disruptions/delays, large wave conditions along the coast, episodes of coastal erosion and strong onshore wind periods. This digital database consists of five informative components that include storm meteorology, storm oceanography, impacts and damages, storm photo’s and images, and data sources. It has identified a set of five storm types for the eastern North Island consisting of Trough/Ridges, East Coast Lows, Subtropical Lows, Tasman Sea Lows, and Cyclone-Anticyclone pair. The two dominant types are Trough/Ridge and East Coast Low, with the Trough pattern involving weather systems primarily from the southern ocean, whilst East Coast Lows involve large cyclones off the coast that can be distantly generated (from the Tasman Sea or subtropics) or locally generated around NZ from southern ocean troughs. The most intense coastal storms off the eastern North Island are East Coast Lows involving cyclones from the subtropics. These storm events reveal blocking-type anticyclones east of the Chatham Islands play a vital role in coastal storm activity by steering cyclones southward towar

Coastal storm activity for the eastern North Island, between East Cape and Wellington, has been quantified from a meteorological perspective through the use of cyclone tracks and extreme winds and from an oceanographic perspective by using hindcast wave information. It has culminated in the production of a high quality, digital coastal storm database for the eastern North Island. Together, this information provides a new understanding of coastal storm behaviour for the eastern North Island. A regional database of historical coastal storms along the eastern North Island between 1930 and 2005 (75 years) is now available in digital format. Coastal storms were identified as bouts of strong winds (greater than or equal to 10.5 m/s) from long-term local wind records from 1962 to 2005, and prior to this period, coastal storms were qualitatively recognised as any event leading to coastal shipping disruptions/delays, large wave conditions along the coast, episodes of coastal erosion and strong onshore wind periods. This digital database consists of five informative components that include storm meteorology, storm oceanography, impacts and damages, storm photo’s and images, and data sources. It has identified a set of five storm types for the eastern North Island consisting of Trough/Ridges, East Coast Lows, Subtropical Lows, Tasman Sea Lows, and Cyclone-Anticyclone pair. The two dominant types are Trough/Ridge and East Coast Low, with the Trough pattern involving weather systems primarily from the southern ocean, whilst East Coast Lows involve large cyclones off the coast that can be distantly generated (from the Tasman Sea or subtropics) or locally generated around NZ from southern ocean troughs. The most intense coastal storms off the eastern North Island are East Coast Lows involving cyclones from the subtropics. These storm events reveal blocking-type anticyclones east of the Chatham Islands play a vital role in coastal storm activity by steering cyclones southward towar

The lack of good ocean surface data on the one-mile or more scale is a major stumbling block for proper evaluation of proposed Mobile Offshore Base (MOB) conceptual designs (Fig. 1). A general model and associated software for stationary, linear, statistical, directional wave systems has been available for some time. If that model can appropriately be used for design of marine mega-structures, then there is no problem in proceeding with conceptual MOB designs and their evaluations. However, it is believed that storm waves might be locally stationary, but on a larger area scale might be nonstationary with patches of clusters of high waves, giving local variances inconsistent with stationary, linear, statistical, directional wave systems. There is a strong need for more knowledge concerning nonlinearity and coherence of storm waves on the mega-structure scale., See also ADM002252. Prepared in cooperation with University of Wyoming, Department of Geology and Geophysics, Laramie, WY.

The variability of infragravity frequency (0.004-0.04 Hz) motions on a wide continental shelf was examined with data from a 100km long transect of bottom pressure recorders extending from the beach (6m depth) to the shelf break (87m depth) near Duck, North Carolina. The observed infragravity motions are a mixture of forced waves, phase coupled to local wave groups, and (uncoupled) free waves. Although the contribution of forced waves to the infragravity energy increases with both increasing swell energy and decreasing water depth, the shelf is usually dominated by free waves. The observed free waves are predominantly radiated from nearby beaches. The strong attenuation of infragravity waves observed across the inner shelf is primarily the result of refractive trapping and is well described by a WKB model. Across the flatter, irregular outer shelf the observed attenuation is weaker but increases with increasing swell energy, suggesting that significant damping occurs on the shelf during storms, consistent with earlier studies. At the deepest instrumented sites, weaker correlations between infragravity and swell energy levels, and weaker depth dependence of infragravity energy levels are observed, suggesting that remotely generated waves are important seaward of the shelf break.

Jack-up offshore structures have a natural period which lies in the high frequency tail of the spectra of North Sea storm waves. This taxi has Significant energy and the jack-up may experience significant dynamic Data have become available from field measurements of the dynamic behaviour of the Maersk Guardian jack-up rig. These data have been compared to simulations performed with Shell's time domain dynamic analysis program "DYNAL". A simplified model of the Maersk Guardian has been developed, and has been used in the simulations under environmental conditions similar to those during the measurements. A comparison has been made between the simulated and the measured deck accelerations and leg forces, by examining spectra and time histories. The results of the simulations were in reasonably good agreement with the measurements. Further research on the damping, the deck to leg connection and the foundation stiffness is desirable., offshore, Hydraulic Engineering, Civil Engineering and Geosciences

Jack-up offshore structures have a natural period which lies in the high frequency tail of the spectra of North Sea storm waves. This taxi has Significant energy and the jack-up may experience significant dynamic Data have become available from field measurements of the dynamic behaviour of the Maersk Guardian jack-up rig. These data have been compared to simulations performed with Shell's time domain dynamic analysis program "DYNAL". A simplified model of the Maersk Guardian has been developed, and has been used in the simulations under environmental conditions similar to those during the measurements. A comparison has been made between the simulated and the measured deck accelerations and leg forces, by examining spectra and time histories. The results of the simulations were in reasonably good agreement with the measurements. Further research on the damping, the deck to leg connection and the foundation stiffness is desirable., offshore, Hydraulic Engineering, Civil Engineering and Geosciences

A two-dimensional numerical model is presented for calculating dune and beach erosion produced by storm waves and water levels. The empirically based model was first developed from a large data set of net cross-shore sand transport rates and geomorphic change observed in large wave tanks, then verified using high-quality field data. The aim is to reproduce macroscale features of the beach profile, with focus on the formation and movement of longshore bars. The ultimate goal is prediction of storm-induced beach erosion and post-storm recovery. Bars are simulated satisfactorily, but berm processes are less well reproduced, due in part to a lack of data for defining accretionary wave and profile processes. A new criterion is developed for predicting erosion and accretion, and the model uses this criterion to calculate net sand transport rates in four regions of the nearshore extending from deep water to the limit of wave runup. Wave height and setup across the profile are calculated to obtain the net cross-shore sand transport rate. The model is driven by engineering data, with main inputs of time series of wave height and period in deep water, time series of water level, median beach grain size, and initial profile shape. Comprehensive sensitivity testing is performed, and example applications are made to evaluate the response of the profile to the presence of a vertical seawall and behavior of different beach fill cross sections in adjustment to normal and storm wave action. Keywords: Accretion; Cross shore sand transport; Dune erosion; Longshore bars.

Previous studies have indicated that certain extremely large waves, measured during Hurricane Camille, might be characterized as non-Gaussian. Waves of similar time-domain description had previously been found to cause ship damages during winter storms. Interviews with ship masters and officers furnished additional important characterizations of these waves, as well as indications of the synoptic weather conditions which were involved. A survey of heavy-weather damage information from Coast Guard records was conducted to evaluate general trends of heavyweather damage to ships. A preponderance of damage is attributed to local wave loadings. Selected cases of ship damage and severe hull girder stressing were examined in relation to the types of extreme waves reported to have been encountered, or believed to have been encountered, based in part upon prevailing synoptic weather conditions. A tentative characterization of large non-Gaussian waves is provided. Recent developments in nonlinear wave mechanics are reviewed to help explain the origin and propagation of these waves. Current studies of the synoptic development of winter storms are examined to identify wind field characteristics which appear to be related to the development of 'rogue' waves.