Hawke's Bay Research Articles

The perspectives of Māori on community treatment orders: A thematic analysis.

To understand the themes for Māori subjected to compulsory community treatment orders. The Mental Health (Compulsory Assessment and Treatment) Act 1992 has been utilised in Aotearoa New Zealand for more than three decades. Despite Māori having higher rates of being subject to community treatment orders, there is little research examining their perspectives of its benefits and harms. Thematic analysis of a purposive sample of Māori in Hawke's Bay, New Zealand. Five themes were developed. Māori described community treatment orders as restrictive and stigmatising. Some Māori described being poorly informed of the structures surrounding the use of community treatment orders and saw it as a mechanism to circumvent information-giving regarding treatment. Counterbalancing these, Māori described community treatment orders as mandating support and saw them as a mechanism to access care. Finally, some described their compulsory treatment status as unimportant and irrelevant. Thematic analysis identified five clear themes from interview participants. Conceptualisation of community treatment orders was largely negative, although Māori acknowledged that being subject to community treatment orders demanded more support from services. Themes of stigma and restriction are common in the literature, however, conception of the use of community treatment orders to bypass consent is novel. The literature describes community treatment orders as providing support, however, in this study, the interpretation suggests a need to lose personal autonomy to receive care, a potentially 'slippery slope' towards a two-tier type service. These findings remind services of the importance of attending to cultural elements of care, being clear around the process of consent. In terms of policy, weaving in cultural understanding appears to be important from an Indigenous perspective.

Addressing workforce distribution and improving care: insights from trainees

Introduction: Plastic surgeons are maldistributed in New Zealand. Regional centres have fewer surgeons and lower surgeon to population ratios than larger metropolitan areas. There is no published data on the future work intentions of plastic surgical trainees in New Zealand. This study examines the career preferences and intentions of plastic surgery trainees in New Zealand as well as perceived barriers to working in a regional centre. Methods: An anonymous online survey was sent to 31 current plastic surgery trainees and recent graduates. Data collected included demographic information, rural background, previous experience in regional centres, family responsibilities, preferred work locations, aspirations for private practice and work–life balance preferences. Results: A total of 25 trainees completed the questionnaire, with a response rate of 81 per cent. A significant proportion of trainees have prior experience in smaller regional centres. Family-friendly work environments and employment for partners were identified as important considerations. The top-ranked regional centres to work in included Queenstown/Wānaka, Hawkes Bay, Nelson and Whangārei. Factors such as the presence of other plastic surgeons, leave policies, after-hours call arrangements and access to a private operating facility were considered essential. Financial considerations, access to quality schooling or childcare, employment opportunities for partners, opportunities for teaching and unit expansion were also important factors. Conclusion: The results of this survey provide insight into the personal and professional factors influencing the career decisions of plastic surgery trainees in New Zealand. The findings highlight the need for strategic workforce planning and engaging relevant stakeholders to address the maldistribution of plastic surgeons, ultimately improving access to specialised care and reducing healthcare disparities for New Zealanders.

Greenhouse gas emissions from New Zealand deer farming systems: current and future options

ABSTRACT Deer production options were modelled in two contrasting environments, Otago and Hawkes Bay, New Zealand, to estimate greenhouse gas emissions, productivity and profitability. A standard New Zealand deer farm was compared to the deer production scenarios: (1) increasing hind longevity through improved reproductive performance, (2) improving animal health management to increase weaner growth, (3) pre-winter finishing using larger hinds and superior growth genetics sires or (4) shifting to a mixed velvet antler/venison enterprise. Production (kg product/ha) increased as scenarios 1–3 were applied, being greatest for scenario 3, in both environments (+21% and +2% in the Otago and Hawkes Bay environments respectively). Production increases in the Hawkes Bay environment were muted by the inclusion of beef and sheep enterprises. Production in Otago and Hawkes Bay was reduced in scenario 4 by 12 and 7% but achieved increased gross margin (33% and 20% respectively). Some small differences in the magnitude of response were seen between the environments. Changes in total GHG emissions per hectare ranged between +4.6% and −6.7%. GHG emission per $ gross margin was reduced by up to 15%–21%. Altering production options in the deer industry altered total GHG emissions per hectare and reduced GHG emissions per kg of product.

Spatiotemporal Evolution of Slow Slip Events at the Offshore Hikurangi Subduction Zone in 2019 Using GNSS, InSAR, and Seafloor Geodetic Data

AbstractDetecting crustal deformation during transient deformation events at offshore subduction zones remains challenging. The spatiotemporal evolution of slow slip events (SSEs) on the offshore Hikurangi subduction zone, New Zealand, during February–July 2019, is revealed through a time‐dependent inversion of onshore and offshore geodetic data that also accounts for spatially varying elastic crustal properties. Our model is constrained by seafloor pressure time series (as a proxy for vertical seafloor deformation), onshore continuous Global Navigation Satellite System (GNSS) data, and Interferometric Synthetic Aperture Radar displacements. Large GNSS displacements onshore and uplift of the seafloor (10–33 mm) require peak slip during the event of 150 to >200 mm at 6–12 km depth offshore Hawkes Bay and Gisborne, comparable to maximum slip observed during previous seafloor pressure deployments at north Hikurangi. The onshore and offshore data reveal a complex evolution of the SSE, over a period of months. Seafloor pressure data indicates the slow slip may have persisted longer near the trench than suggested by onshore GNSS stations in both the Gisborne and Hawkes Bay regions. Seafloor pressure data also reveal up‐dip migration of SSE slip beneath Hawke Bay occurred over a period of a few weeks. The SSE source region appears to coincide with locations of the March 1947 Mw 7.0–7.1 tsunami earthquake offshore Gisborne and estimated great earthquake rupture sources from paleoseismic investigations offshore Hawkes Bay, suggesting that the shallow megathrust at north and central Hikurangi is capable of both seismic and aseismic rupture.

Risk Assessment of Displaced Sediment by an Extreme Event Cyclone in a Peri-Urban Zone Using Bioassays and Analytical Chemistry.

Hawke's Bay in New Zealand was impacted by Cyclone Gabrielle in 2023, experiencing intense weather conditions and rainfall. Rivers and streams surged beyond their banks, displacing large amounts of sediment. The sewage treatment plant and industries in the Waitangi catchment, south of the city of Napier, were heavily impacted, making them potential sources of contaminants. The aim of this study was to investigate the risk of displaced sediments deposited south of Napier City, using bioassays and chemical analysis methods. Sediment samples were collected across a gradient between the coastline and the Waitangi Stream. The toxicity of chemically extracted or elutriate samples was assessed by Microtox®, mussel embryo-larval development, and aryl hydrocarbon and constitutive androstane receptor yeast two-hybrid assays. Targeted chemical analysis and automated identification and quantification system (AIQS-GC) methods were used to identify contaminants. The elutriates showed low toxicity and the yeast assays showed levels of activity like those previously reported. Chemical methods confirmed historical contamination by DDT and its metabolites DDE and DDD, as well as by plant sterols. Overall, the toxicity and chemicals detected are what would be expected from a typical agricultural soil. The risk posed by the displaced sediment in the Waitangi catchment can be considered low. Combining chemical and bioanalytical methods was an effective approach to investigate the potential risks of post-disaster contamination.

Qualitative Study of Combined Heart Failure Rehabilitation Patients to Understand the Enablers and Barriers to Access HF Rehabilitation for Indigenous People in Hawkes Bay, New Zealand

Qualitative Study of Combined Heart Failure Rehabilitation Patients to Understand the Enablers and Barriers to Access HF Rehabilitation for Indigenous People in Hawkes Bay, New Zealand

Telehealth Remote Rural Clinics for Timely Up-Titration as Per GDMT in Rural Isolated Regions of Hawkes Bay, New Zealand

Telehealth Remote Rural Clinics for Timely Up-Titration as Per GDMT in Rural Isolated Regions of Hawkes Bay, New Zealand

A first survey for herbicide resistant weeds across major maize growing areas in the North Island of New Zealand.

Weeds are increasingly documented with evolved resistance to herbicides globally. Three species have been reported as resistant in maize crops in New Zealand: Chenopodium album to atrazine and dicamba, Persicaria maculosa to atrazine and Digitaria sanguinalis to nicosulfuron. Despite knowledge of these cases, the distribution of these resistant biotypes is unknown. This study aimed to determine the prevalence of known resistant weeds in major maize growing areas in New Zealand, and to pro-actively screen other species for resistance. Weed seeds of broadleaf and grass species were collected from 70 randomly selected maize growing farms in the North Island in 2021-2022. Seeds were grown and treated with herbicides at recommended field rates. Atrazine-resistant C. album were recorded in a third of surveyed farms and nicosulfuron-resistant D. sanguinalis in a sixth. Half of Waikato farms and a quarter of Bay of Plenty farms (no Hawkes Bay or Wellington farms) had atrazine-resistant C. album. Dicamba-resistant C. album were not detected, nor were atrazine-resistant P. maculosa. Nicosulfuron resistant D. sanguinalis was recorded in 19% of Waikato farms, 6% of Bay of Plenty farms and 9% of Hawkes Bay farms (no Wellington farms). Amaranthus spp., Fallopia convolvulus, Persicaria spp., Solanum spp., Echinochloa crus-galli, Panicum spp. and Setaria spp. were not resistant to any of the herbicides tested. Twenty-nine to 52% of maize farms in the North Island are estimated to have herbicide resistant weeds. Resistance is common in maize farms in Waikato and western Bay of Plenty. Resistance is rare in southern regions, with only one instance of nicosulfuron-resistant D. sanguinalis and no resistant C. album. Most annual weeds in maize are not resistant to herbicides; although atrazine resistant C. album is widespread, it is currently controlled with alternative herbicides. Resistant D. sanguinalis appears to be an emerging problem.

The cost of doing nothing about a sleeper weed-Nassella neesiana in New Zealand.

Nassella neesiana (Chilean needle grass), an invasive 'sleeper weed' established in sheep and beef pastures in three of New Zealand's sixteen local government regions, has a potential geographic range amounting to 3.96 million hectares spanning all regions except the West Coast. It impacts the productivity, market value and welfare of livestock through its sharp penetrating that cause blindness and the downgrading of wool, hides, and carcasses. In this study we estimate the benefit of preventing its spread as the present value (PV) of local (regional) and national productivity losses that would accrue over 200 years under a 'do nothing' spread scenario. Using a 3% discount rate and two assumed spread rates, 201 and 100 years to 90% occupation of its potential range, we calculate national PV losses of NZ$ 192 million and NZ$ 1,160 million respectively. In a breakeven analysis, these losses, which equate to the national benefits of preventing the spread, justify annual expenditures of NZ$ 5.3 million and NZ$ 34 million respectively. Restricting the analyses to the regions with known infestations (Hawke's Bay, Marlborough, Canterbury) provided much lower estimates of the benefits (ranging from NZ$ 16.8 million to NZ$ 158 million) because spillover benefits from preventing spread to the other susceptible regions are not accounted for. These analyses support a nationally coordinated approach to managing N. neesiana in New Zealand involving surveillance and control measures respectively in the susceptible and infested regions.

Terminal Ediacaran–Late Ordovician evolution of the NE Laurentia palaeocontinent: rift–drift–onset of Taconic Orogeny, sea-level change and ‘Hawke Bay’ onlap (not offlap)

Abstract Rodinia break-up with late Ediacaran rifting defined a NE Laurentia triple junction (New York Promontory–Ottawa–Bonnechere aulacogen (OBA)–Quebec Reentrant). Rifting persisted to c. 510 Ma. The oldest passive-margin shelf units (Forestdale Marble and Moosalamoo Phyllite) underlie a sandstone (Cheshire) commonly regarded as the oldest passive unit. Late Dyeran–Middle Cambrian rifting led to the oldest OBa sedimentation and formed the Franklin Basin (NW Vermont). Cambrian–Darriwillian shelf–slope facies are linked eustatically – not Taconic Orogeny onset. Onlap and shelf carbonates are coeval with black slope mud; and lowstand shelf unconformities with green, oxic slope mud. Early–middle Dyeran eustatic change defined slope units: (1) Browns Pond Formation dysoxic–anoxic (d–a) interval with debrite cap (Holcombville Member, new); (2) Middle Granville Formation Oxic Interval (new); and (3) lower Hatch Hill Formation d–a interval. Our analysis leads to two controversial conclusions: (i) the existence of the Dashwoods and other micro-continental blocks due to hyperextension is not supported by cover sequences linking Laurentia to proposed Dashwoods areas (i.e. Green Mountains) and an arc origin of the type Dashwoods; and (ii) ‘Hawke Bay Event(s)’, widely interpreted as Cambrian global regressive event(s), is a local highstand systems tract facies with shelf sand bypass onto the Hatch Hill Formation slope in its NE Laurentia type region.

Phenological phase affects carrot seed production sensitivity to climate change – A panel data analysis

New Zealand is a major producer of carrot seeds globally. Carrots are an important nutritional crop for human consumption. Since the growth and development of carrot seed crops mainly depend on climatic factors, seed yield is extremely susceptible to climate change. This modeling study was undertaken using a panel data approach to determine the impact of the atmospheric conditions (proxied by maximum and minimum temperature) and precipitation during the critical growth stages for seed production in carrot, viz., juvenile phase, vernalization phase, floral development phase, and flowering and seed development phase on carrot seed yield. The panel dataset was created using cross-sections from 28 locations within the Canterbury and Hawke's Bay regions of New Zealand that cultivate carrot seed crops and time series from 2005 to 2022. Pre-diagnostic tests were performed to test the model assumptions, and a fixed effect model was selected subsequently. There was significant (p < 0.01) variability in temperature and rainfall throughout different growing phases, except for precipitation at the vernalization phase. The highest rate of changes in maximum temperature, minimum temperature, and precipitation were recorded during the vernalization phase (+0.254 °C per year), floral development phase (+0.18 °C per year), and juvenile phase (−6.508 mm per year), respectively. Based on marginal effect analysis, the highest significant influence of minimum (187.724 kg/ha of seed yield decrease for each 1 °C increment) and maximum temperature (1 °C rise increases seed yield by 132.728 kg/ha), and precipitation (1 mm increment of rainfall decreases the seed yield by 1.745 kg/ha) on carrot seed yield were reported at vernalization, and flowering and seed development, respectively. The minimum and maximum temperatures have a higher marginal effect on carrot seed production. Analysis of the panel data demonstrates that the production of carrot seeds will be vulnerable to climatic change.

Heart Failure Rehabilitation Impacts Quality of Life and Readmissions: Breathlessness Rehabilitation Classes Integrating Heart Failure and Pulmonary Rehabilitation Made Positive Impact on Quality of Life, Health Literacy, and Readmissions

Heart Failure (HF) patients often have limited exercise capacity due to dyspnoea and fatigue. Despite the availability of effective treatment, HF is associated with poor quality of life (QOL), high morbidity and mortality. Māori are twice as likely to die and four times as likely to be hospitalised for HF. Heart failure hospitalisations cost an estimated 2% to the New Zealand health system. Until the late 1980s, exercise was considered unsafe for HF; since then, considerable research evidence has suggested that exercise is safe and provides substantial physiological and psychological benefits. Whilst potential benefits are clear, there were no guidelines or resources available for HF patients in Hawkes Bay. With aim of improving functional capacity and QOL for HF patients and reduce readmissions, rehabilitation space was explored. Fiscal budgets and need of a multidisciplinary team were barriers to idealistic HF rehabilitation. The HF rehabilitation was integrated into pulmonary rehabilitation, with modification as per HF guidelines on exercise, content, and training of all staff regarding cardiology. The HF rehabilitation classes commenced in rural and urban regions (four regions in total). Patients were selected as per referral criteria and the first assessment was completed by the cardiologist/nurse practitioner/clinical nurse specialist and referred to an 8-week rehabilitation program. QOL tools were used to measure the before and after outcomes. More than 200 patients were referred and evaluated for results. Twenty-five HF patients were interviewed to understand enablers and barriers to rehabilitation. The HF patients who attended the program were almost 50% less likely to be readmitted, had reduced breathlessness, and improved fitness. Self-management skills and health literacy were also improved. Heart failure rehabilitation has proven to be a low-cost, high-value intervention, but is generally underused.

Invasive group A streptococcal disease in Hawke's Bay, New Zealand: epidemiology, manifestations and impact.

To describe the epidemiology, clinical features and healthcare impact of invasive group A streptococcal (iGAS) disease in Hawke's Bay from 2016 to 2021, to inform public health efforts. The case definition of iGAS for this study was isolation of group A streptococcus (GAS) from blood culture. "Severe iGAS" included cases that required intensive care admission or died within 60 days. Cases were identified retrospectively from the Te Whatu Ora Te Matau a Māui Hawke's Bay laboratory database. Clinical data were obtained from inpatient electronic health records. A total of 93 cases of iGAS were identified in Hawke's Bay during the 6-year study period. The overall age-standardised incidence of iGAS was 5.6 per 100,000 (95%CI 4.1-7.4). The incidence was significantly higher among people of Pacific, Māori and Asian ethnicities than European/Other ethnicities, and higher in areas of socio-economic disadvantage. Skin infections were the most common source (70% of cases). Thirty-seven cases (41%) were classified as severe, including 11 deaths (12% case fatality rate). Further action is required to address inequities in social determinants of skin health in Hawke's Bay. Mandatory national notification of iGAS would provide opportunity for improved surveillance of GAS-related disease, and consideration of a public health response to iGAS disease in New Zealand.

Site‐specific estimation of spatiotemporal crop evapotranspiration through field‐level sensing data

AbstractThis study integrated field‐level sensor data into the FAO‐56 Penman–Monteith algorithm to provide a site‐specific estimate of crop evapotranspiration. This was carried out at two contrasting sites for pea and bean (Manawatū) and barley (Hawke's Bay) crops managed within two irrigation management zones, at each site, under variable‐rate irrigation systems in New Zealand. Daily crop evapotranspiration estimates were calculated using data from a weather station situated at the field site combined with in‐field crop sensing data (spectral reflectance, canopy temperature, and canopy height). In addition, calibrated soil moisture data were used with a soil water balance model to compare estimations of daily crop evapotranspiration with those estimated using the crop sensing method. The results indicated that variable crop responses to different irrigation strategies and soil types provided a good opportunity to quantify different levels of spectral reflectance, canopy temperature, and consequently the estimation of crop water use. The statistical comparisons revealed that the modified FAO‐56 Penman–Monteith using crop sensor data compared well with the more conventional soil water balance approach using soil moisture data (R2 = 0.70, 0.83, 0.91 for barley, pea, and bean, respectively). Overall, the results from this study indicated that crop sensing approaches combined with the FAO‐56 Penman–Monteith model have potential to provide a more easily determined site‐specific field estimation of crop evapotranspiration than other methods, and it can take into consideration the spatiotemporal variability of crop growth in a field.

How to perform laparoscopic common bile duct exploration through a transverse choledochotomy.

This article reviews common bile duct stones and describes our technique of laparoscopic common bile duct exploration (LCBDE) through a transverse choledochotomy at Hawke's Bay Hospital, New Zealand.

TESTING IN VEIN: ARE ROUTINE BLOOD TESTS REQUIRED FOR UNCOMPLICATED ARTHROPLASTY? A RETROSPECTIVE COHORT STUDY

Routine post-operative bloods following all elective arthroplasty may be unnecessary. This retrospective cohort study aims to define the proportion of post-operative tests altering clinical management.Clinical coding identified all elective hip or knee joint replacement under Hawkes Bay District Health Board contract between September 2019-December 2020 (N=373). Uni-compartmental and bilateral replacements, procedures performed for cancer, and those with insufficient data were excluded. Demographics, perioperative technique, and medical complication data was collected. Pre- and post-operative blood tests were assessed. Outcome measures included clinical intervention for abnormal post-operative sodium (Na), creatinine (Cr), haemoglobin (Hb), or potassium (K) levels. A cost-benefit analysis assessed unnecessary testing.350 patients were Included. Median age was 71 (range 34-92), with 46.9% male. Only 26 abnormal post-operative results required intervention (7.1%). 11 interventions were for low Na, 4 for low K, and 4 for elevated Cr. Only 7 patients were transfused blood products. Older age (p=0.009) and higher ASA (p=0.02) were associated with intervention of any kind. Abnormal preoperative results significantly predicted intervention for Na (p&lt;0.05) and Cr (p&lt;0.05). All patients requiring treatment for K used diuretic medication. Preoperative Hb level was not associated with need for transfusion. Overall, there were 1027 unnecessary investigations resulting in $18,307 excess expenditure.Our study identified that the majority of elective arthroplasty patients do not require routine postoperative blood testing. We recommend investigations for patients with preoperative electrolyte abnormality, those taking diuretics, and patients with significant blood loss noted intra-operatively. In future, a larger, randomised controlled trial would be useful to confirm these factors.

Using Seafloor Geodesy to Detect Vertical Deformation at the Hikurangi Subduction Zone: Insights From Self‐Calibrating Pressure Sensors and Ocean General Circulation Models

AbstractSeafloor pressure sensor data is emerging as a promising approach to resolve vertical displacement of the seafloor in the offshore reaches of subduction zones, particularly in response to slow slip events (SSEs), although such signals are challenging to resolve due to sensor drift and oceanographic signals. Constraining offshore SSE slip distribution is of key importance to understanding earthquake and tsunami hazards posed by subduction zones. We processed seafloor pressure data from January to October 2019 acquired at the Hikurangi subduction zone, offshore New Zealand, to estimate vertical displacement associated with a large SSE that occurred beneath the seafloor array. The experiment included three self‐calibrating sensors designed to remove sensor drift, which, together with ocean general circulation models, were essential to the identification and correction of long‐period ocean variability remaining in the data after applying traditional processing techniques. We estimate that long‐period oceanographic signals that were not synchronous between pressure sensors and reference sites influenced our inferred displacements by 0.3–2.6 cm, suggesting that regionally deployed reference sites alone may not provide sufficient ocean noise correction. After incorporating long‐period ocean variability corrections into the processing, we calculate 1.0–3.3 cm of uplift during the SSE offshore Gisborne at northern Hikurangi, and 1.1–2.7 cm of uplift offshore the Hawke's Bay area at central Hikurangi. Some Hawke Bay displacements detected by pressure sensors near the trench were delayed by 6 weeks compared to the timing of slip onset detected by onshore Global Navigation Satellite System sites, suggesting updip migration of the SSE.

Holocene marine terraces as recorders of earthquake uplift: Insights from a rocky coast in southern Hawke's Bay, New Zealand

AbstractOn rocky tectonic coasts, data from Holocene marine terraces may constrain the timing of coseismic uplift and help identify the causative faults. Challenges in marine terrace investigations include: (1) identifying the uplift datums; (2) obtaining ages that tightly constrain the timing of uplift; (3) distinguishing tsunami deposits from beach deposits on terraces; and (4) identifying missing terraces and hence earthquakes. We address some of these challenges through comparing modern beach sediments and radiocarbon ages with those from a trench excavated across three terraces at Aramoana, central Hikurangi Subduction Margin, New Zealand. Sedimentary analyses identified beach and dune deposits on terraces but could not differentiate specific environments within them. Modern beach shells yielded modern radiocarbon ages, regardless of position or species, showing age inheritance and habitat is likely not an issue when dating shells on these terraces. By integrating terrace mapping, stratigraphy, morphology, and radiocarbon ages we develop a conceptual model of coastal uplift and terrace formation following at least two, possibly three, earthquakes at 5490–5070, 2620–2180, and 950–650 cal. yr bp. A high step and time gap between the upper two terraces raises the possibility that at least one intervening terrace is completely eroded. The trench exposure also showed that terrace stratigraphy may differ from that inferred from surface geomorphology, with apparent beach ridges being of composite origin and draping of younger beach deposits on the outer edge of a previous terrace. Dislocation modelling and comparison of marine terrace and earthquake ages from ~4 km south and ≤ 73 km north confirms that the most likely earthquake source is the nearshore, landward‐dipping, Kairakau Fault. Alternative sources, such as multi‐fault ruptures of the Kairakau‐Waimārama faults or Hikurangi subduction earthquakes, and/or a combination of the two are also possible and should be examined in future studies.

Tectonic and Climate-Controlled Hazards on the Shores of Hawke's Bay, New Zealand

Komar, P.D. and Harris, E., 2022. Tectonic and climate-controlled hazards on the shores of Hawke's Bay, New Zealand. Journal of Coastal Research, 38(6), 1075–1095. Coconut Creek (Florida), ISSN 0749-0208. Elevations of the Hawke's Bay shore on the Pacific coast of New Zealand were altered by an earthquake in 1931, such that at its north end the gravel beach and shore-front properties were raised by 2 m, while elevations dropped by 1 m at its south end. Along the elevated shore, the morphology was altered from a low-lying gravel spit that had experienced frequent overwash events, changed to a gravel barrier ridge where its increased stability permitted construction of expensive homes. The central stretch of shore, where there was minimal change in elevations, continues to experience wave overtopping during storms and high tides, just as had occurred prior to the earthquake. The southern-most shore, where subsidence took place, experiences substantial property damage during winter storms. With projections of accelerated rates of rising sea levels and increased storm intensities produced by global warming, concerns are that the developed shore of the elevated gravel ridge will again suffer from erosion and overwash flooding. Analyses have been undertaken of the hourly measured tides, waves, and calculated swash run-up levels on the beaches, combined to yield a record of hourly total water levels at the shore. Its extremes have been compared with the elevations of the surveyed gravel ridges to yield assessments of the potential erosion and flooding hazards. Still greater hazard assessments have been based on a recognition that the morphologies of the surveyed ridges provide direct evidence for the most extreme water levels that occurred at times of major storms in the distant past, prior to the availability of the process data. Assessments of hazards expected 100 years into the future have included projections of both rising sea levels and evidence for increasing storm-wave heights.

Likelihood of offshore freshened groundwater in New Zealand

Offshore aquifer research is an emerging field that is becoming increasingly important as population growth and climate change put pressure on coastal water resources. One of the largest reserves, globally, of offshore freshened groundwater (OFG) was recently identified off the South Island of New Zealand. This has highlighted the potential for OFG elsewhere in New Zealand. This study aims to: (1) screen for New Zealand coastal aquifers most likely to contain OFG and, (2) document evidence for OFG in New Zealand. An OFG-likelihood rating scheme was developed as part of the study. An application of the rating scheme used survey responses from regional councils responsible for groundwater management, in combination with national and regional-scale technical documents. The rating scheme was found to be a simple and transparent first-pass approach for highlighting areas where OFG is more or less likely at the national scale. Results are presented in a map showing the likelihood of OFG around the New Zealand coastline. Regions with aquifers where OFG likelihood is high include Greater Wellington, Canterbury, Tasman, Hawkes Bay and Marlborough. Aquifers in these regions are associated with major fluvial depositional systems, including glacial outwash gravels. Despite high dependence on groundwater in these regions and extensive groundwater extraction near the coast, there are no major reported incidences of seawater intrusion, suggesting offshore groundwater may be augmenting onshore extraction.