ECoast Ltd.

Raglan, New Zealand

ECoast Ltd.

Raglan, New Zealand
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Eriksen M.,Five GyResearch Institute | Lebreton L.C.M.,Dumpark Data Science | Carson H.S.,University of Hawaii at Hilo | Thiel M.,Católica del Norte University | And 5 more authors.
PLoS ONE | Year: 2014

Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the world's oceans from 24 expeditions (2007-2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N5680) and visual survey transects of large plastic debris (N5891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface.


Borrero J.C.,ASR Ltd. Marine Consulting and Research | Borrero J.C.,University of Southern California | Borrero J.C.,ECoast Ltd | Bell R.,NIWA - National Institute of Water and Atmospheric Research | And 7 more authors.
Pure and Applied Geophysics | Year: 2013

The great Tohoku-oki earthquake of March 11, 2011 generated a devastating tsunami in the near field as well as substantial far-field effects throughout the Pacific Ocean. In New Zealand, the tsunami was widely observed and instrumentally recorded on an extensive array of coastal tidal gauges and supplemented by current velocity data from two sites. While the tsunami's first arrival was on the morning of March 12 in New Zealand, the strongest effects occurred throughout that afternoon and into the following day. Tsunami effects consisted primarily of rapid changes in water level and associated strong currents that affected numerous bays, harbors, tidal inlets and marine facilities, particularly on the northern and eastern shores of the North Island. The tsunami caused moderate damage and significant overland flooding at one location. The tsunami signal was clearly evident on tide gauge recordings for well over 2 days, clearly illustrating the extended duration of far field tsunami hazards. Real time analysis and modelling of the tsunami through the night of March 11, as the tsunami crossed the Pacific, was used as a basis for escalating the predicted threat level for the northern region of New Zealand. A comparison to recorded data following the tsunami shows that these real time prediction models were accurate despite the coarse near-shore bathymetry used in the assessment, suggesting the efficacy of such techniques for future events from far-field sources. © 2012 Springer Basel AG.


PubMed | Dumpark Data Science, University of Western Australia, Five GyResearch Institute, eCoast Ltd and 5 more.
Type: Journal Article | Journal: PloS one | Year: 2016

Plastic pollution is ubiquitous throughout the marine environment, yet estimates of the global abundance and weight of floating plastics have lacked data, particularly from the Southern Hemisphere and remote regions. Here we report an estimate of the total number of plastic particles and their weight floating in the worlds oceans from 24 expeditions (2007-2013) across all five sub-tropical gyres, costal Australia, Bay of Bengal and the Mediterranean Sea conducting surface net tows (N=680) and visual survey transects of large plastic debris (N=891). Using an oceanographic model of floating debris dispersal calibrated by our data, and correcting for wind-driven vertical mixing, we estimate a minimum of 5.25 trillion particles weighing 268,940 tons. When comparing between four size classes, two microplastic <4.75 mm and meso- and macroplastic >4.75 mm, a tremendous loss of microplastics is observed from the sea surface compared to expected rates of fragmentation, suggesting there are mechanisms at play that remove <4.75 mm plastic particles from the ocean surface.


Lebreton L.C.-M.,ASR Ltd. | Borrero J.C.,University of Southern California | Borrero J.C.,ECoast Ltd.
Marine Pollution Bulletin | Year: 2013

A global ocean circulation model is coupled to a particle-tracking model to simulate the transport of floating debris washed into the North Pacific Ocean by the Tohoku tsunami. A release scenario for the tsunami debris is based on coastal population and measured tsunami runup. Archived 2011/2012 hindcast current data is used to model the transport of debris since the tsunami, while data from 2008 to 2012 is used to investigate the distribution of debris on timescales up to 4. years. The vast amount of debris pushed into ocean likely represents thousands of years worth of 'normal' litter flux from Japan's urbanized coastline. This is important since a significant fraction of the debris will be comprised of plastics, some of which will degrade into tiny particles and be consumed by marine organisms, thereby allowing adsorbed organic pollutants to enter our food supply in quantities much higher than present. © 2012 Elsevier Ltd.


Admire A.R.,Humboldt State University | Dengler L.A.,Humboldt State University | Crawford G.B.,Vancouver Island University | Uslu B.U.,National Oceanic and Atmospheric Administration | And 4 more authors.
Pure and Applied Geophysics | Year: 2014

We investigate the currents produced by recent tsunamis in Humboldt Bay and Crescent City, California. The region is susceptible to both near-field and far-field tsunamis and has a historic record of damaging events. Crescent City Harbor, located approximately 100 kms north of Humboldt Bay, suffered US $28 million in damages from strong currents produced by the 2006 Kuril Islands tsunami and an additional US $26 million from the 2011 Japan tsunami. In order to better evaluate these currents in northern California, we deployed a Nortek Aquadopp 600 kHz 2D acoustic Doppler current profiler (ADCP) with a 1-min sampling interval in Humboldt Bay, near the existing National Oceanic and Atmospheric Administration (NOAA) National Ocean Service (NOS) tide gauge station. The instrument recorded the tsunamis produced by the Mw 8.8 Chile earthquake on February 27, 2010 and the Mw 9.0 Japan earthquake on March 11, 2011. One other tsunami was recorded on the Humboldt Bay tide gauge during the period of ADCP operation, but was not visible on the ADCP, suggesting a threshold water level value of about 0.2 m to produce an observable ADCP record. The 2010 tsunami currents persisted in Humboldt Bay for approximately 30 h with peak amplitudes of about 0.35 m/s. The 2011 tsunami signal lasted for over 40 h with peak amplitude of 0.84 m/s. The strongest currents corresponded to the maximum change in water level approximately 67 min after the initial wave arrival. No damage was observed in Humboldt Bay for either event. In Crescent City, currents for the first three and one-half hours of the 2011 Japan tsunami were estimated using security camera video footage from the Harbor Master, approximately 70 m away from the NOAA–NOS tide gauge station. The largest amplitude tide gauge water-level oscillations and most of the damage occurred within this time window. The currents reached a velocity of approximately 4.5 m/s and six cycles exceeded 3 m/s during this period. Measured current velocities both in Humboldt Bay and in Crescent City were compared to calculated velocities from the Method of Splitting Tsunamis (MOST) numerical model. The frequency and pattern of current amplification and decay at both locations are replicated by the MOST model for the first several hours after the tsunami onset. MOST generally underestimates 2011 peak current velocities by about 10–30 %, with a few peaks by as much as 50 %. At Humboldt Bay, MOST predicted attenuation of the signal after 4 h but the actual signal persisted at a nearly constant level for at least twice as long. The results from this project demonstrate that ADCPs can effectively record tsunami currents for small to moderate events and can be used to calibrate and validate models (i.e., MOST) in order to better understand hazardous tsunami conditions within harbors. © 2014, Springer Basel.


Borrero J.C.,eCoast Ltd. | Borrero J.C.,University of Southern California | Goring D.G.,Mulgor Consulting
Pure and Applied Geophysics | Year: 2015

At 2347 UTC on April 1, 2014 (12:47 pm April 2, 2014 NZDT) an earthquake with a moment magnitude of 8.2 occurred offshore of Iquique in northern Chile. The temblor generated a tsunami that was observed locally and recorded on tide gauges and deep ocean tsunameters close to the source region. While real time modeling based on inverted tsunameter data and finite fault solutions of the earthquake rupture suggested that a damaging far-field tsunami was not expected (and later confirmed), this event nevertheless reminded us of the threat posed to New Zealand by tsunami generated along the west coast of South America and from the Peru/Chile border region in particular. In this paper we quantitatively assess the tsunami hazard at Lyttelton Harbor from South American tsunamis through a review of historical accounts, numerical modeling of past events and analysis of water level records. A sensitivity study for tsunamis generated along the length of the South American Subduction Zone is used to illustrate which section of the subduction zone would generate the strongest response at Lyttelton while deterministic scenario modeling of significant historical South American tsunamis (i.e. 1868, 1877 and 1960) provide a quantitative estimate of the expected effects from possible future great earthquakes along the coast of South America. © 2015, Springer Basel.


Borrero J.C.,ECoast Ltd | Borrero J.C.,University of Southern California | Lynett P.J.,University of Southern California | Kalligeris N.,University of Southern California
Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences | Year: 2015

Tsunami-induced currents present an obvious hazard to maritime activities and ports in particular. The historical record is replete with accounts from ship captains and harbour masters describing their fateful encounters with currents and surges caused by these destructive waves. Despite the well-known hazard, only since the trans-oceanic tsunamis of the early twenty-first century (2004, 2010 and 2011) have coastal and port engineering practitioners begun to develop port-specific warning and response products that accurately assess the effects of tsunamiinduced currents in addition to overland flooding and inundation. The hazard from strong currents induced by far-field tsunami remains an underappreciated risk in the port and maritime community. In this paper, we will discuss the history of tsunami current observations in ports, look into the current state of the art in port tsunami hazard assessment and discuss future research trends. Copyright © 2015 The Author(s) Published by the Royal Society.


Borrero J.C.,ECoast Ltd. | Borrero J.C.,University of Southern California | Greer S.D.,ECoast Ltd.
Pure and Applied Geophysics | Year: 2013

In this study we analyze water level data from coastal tide gauges and deep-ocean tsunameters to explore the far-field characteristics of two major trans-Pacific tsunamis, the 2010 Chile and the 2011 Japan (Tohoku-oki) events. We focused our attention on data recorded in California (14 stations) and New Zealand (31 stations) as well as on tsunameters situated along the tsunami path and proximal to the study sites. Our analysis considers statistical analyses of the time series to determine arrival times of the tsunami as well as the timing of the largest waves and the highest absolute sea levels. Fourier and wavelet analysis were used to describe the spectral content of the tsunami signal. These characteristics were then compared between the two events to highlight similarities and differences between the signals as a function of the receiving environment and the tsunami source. This study provides a comprehensive analysis of far-field tsunami characteristics in the Pacific Ocean, which has not experienced a major tsunami in nearly 50 years. As such, it systematically describes the tsunami response characteristics of modern maritime infrastructure in New Zealand and California and will be of value for future tsunami hazard assessments in both countries. © 2012 Springer Basel AG.


Goring D.G.,Mulgor Consulting Ltd. | Borrero J.C.,ECoast Ltd.
Australian Coasts and Ports 2015 Conference | Year: 2015

Time-frequency analysis involves partially transforming a time series into the frequency domain. It is more appropriate than Fourier analysis for transient signals like tsunami. Two methods are presented: orthogonal wavelet decomposition in which a predetermined basis function is used for the transformation; and empirical mode decomposition in which the basis function emerges from the data themselves. Both are shown to provide detailed information about the structure of the tsunami waves, but wavelet analysis is preferred because it can better handle the abrupt arrival of tsunami waves and comparisons can be easily made between different sites and different events.


Haggitt T.R.,ECoast Ltd | Mead S.T.,ECoast Ltd
Australian Coasts and Ports 2015 Conference | Year: 2015

Makara Estuary is the southernmost estuary on the north-western coast of Wellington, New Zealand. The steep catchment surrounding Makara Estuary is predominantly utilised for farming and forestry. Monitoring of the benthic ecology, sedimentation rates and identifying regions of erosion within the Makara Estuary has been undertaken over the last 3 years, as part of resource consent condition monitoring for Meridian Energy's Mill Creek wind farm development. Baseline pre-construction surveys at 3 sampling locations within the estuary revealed a degraded estuary characterised by anoxic surficial sediments, together with low diversity and abundance of infanual and epifaunal organisms. Various sites of active erosion both within and upstream of the estuary proper were also apparent, making effects-based assessments difficult. Subsequent monitoring of the estuary has revealed a suite of stressors that are negatively impacting the ecological integrity and functioning of the estuary. Many of these are associated with poor land-use practices; although, natural disturbance events associated with large-scale macroalgal deposition also impacts the estuary. The rate of sedimentation has been estimated to be around 14 mm/yr, which while relatively high, is in line with estuaries that have forestry production in their catchment. While infaunal community composition and the abundance of several polychaete species changed (increased and decreased) over the course of monitoring and differences between pre-construction and construction-phase surveys were apparent, there was no completing evidence that wind turbine construction has significantly altered benthic community composition or accelerated rates of sedimentation within the estuary. In this paper we present results from biological and physical monitoring, discuss the difficulties of undertaking effects-based monitoring in a degraded, yet dynamic, estuarine environment and outline ways in which the impacts to the estuary could be reduced with focused initiatives. Outside of the context of resource consent monitoring, it is anticipated that results of benthic and physical sampling will provide important information on the on-going state of the Makara Estuary to regulatory authorities and the wider Makara community.

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