title: Environmental aspects of storm runoff discharge from a timber port, Tauranga, New Zealand

authors: Tian, Fengming

subjects: storm runoff water

abstract: An investigation was undertaken into storm runoff water quantity and quality, contaminant input to the receiving tidal waters from the Mt. Maunganui wharf, accumulation of potentially toxic resin acids in adjacent sediments, and the dilution of the wharf runoff in the receiving tidal waters, in order to assess the possible adverse environmental impact associated with the log operation at the Port of Tauranga Ltd.
Based upon field data and rainfall records, about a half of the annual precipitation over the log handling areas is converted to surface runoff (117,000 m³a⁻¹). Annual runoff volume per hectare of wharf surface is estimated as 7,500 m³ha⁻¹a⁻¹ for the sealed area and 3,700 m³ha⁻¹a⁻¹ for the gravelled area.
The optical quality of the wharf runoff is degraded due to addition of bark and soil particles. The black disk visual clarity (0.01-0.02 m) was only 0.5-1.0% of that in the receiving tidal waters. The wharf runoff appears very dark gray to yellowish brown in apparent colour (10YR1/3 to 10YR5/6 Munsell colour chart) and has a soluble yellow substance concentration of about 25 m⁻¹. Power relationships between the traditionally used parameters, for example, suspended solids and turbidity, were identified. The wharf surface pavement types had a significant influence on visual clarity, but little influence on yellow substance concentration.
The potentially toxic resin acids in the wharf runoff have been determined with SIM GC-MS. The average total resin acid level (1,030 ppb) is comparable to that of 1,000 ppb reported at which acute toxicity is likely to be exhibited. A relationship of resin acids against volatile suspended solids was established. Tests undertaken suggest that conventional treatment methods of natural sedimentation and flocculation-sedimentation are able to remove the resin acids effectively.
The levels of biological oxygen demand (BOD), total phosphorus and nitrogen in the wharf runoff are considerably higher than those of common urban runoff. However, the wharf runoff contributes little nitrate nitrogen and oil and grease to the receiving environment.
About 87,500 kg of suspended solids, 43,000 kg of volatile suspended solids, 14,200 kg of BOD, 500 kg of phosphorus, and 103 kg of resin acids are discharged to the Tauranga Harbour annually from runoff from the Mt. Maunganui wharf.
Analyses show that the impact on adjacent sediments from the storm runoff is limited to a distance of about 100 m from the discharge points and the resin acid levels in the sediments within this distance are not significantly higher compared to that of the storm runoff. The net resin acid accumulation rate in the shipping channel (Stella Passage) beside the log handling areas was estimated to be in the range of 300 to 370 ppb per year.
Based on field investigation and numerical simulations, the findings on dispersion and dilution of the wharf runoff in the receiving tidal waters are as follows: (i) the sea water around Stella Passage experiences an obvious natural salinity stratification, the extent of which depends greatly on the weather conditions; (ii) the wind drag stress and the pressure gradient caused by the addition of runoff had the greatest influence on the plume dynamics during the flood tide. The plumes basically remain within the top 2-3 m of the water column under different winds; (iii) the plume is unlikely to advect to the Whareroa Marae under strong (30-40 knots) easterly or northeasterly winds for a storm with a 5-year return period. However, there is an obvious influence on the Whareroa Marae under 30- 40 knot northerly winds; and (iv) the short duration and restricted region of the low dilution pulse of effluent around slack water may explain why there has been no reports of acute toxic events.
Sealing the gravel covered wharf area, improving the sweeping efficiency, and extending the present outfalls to the sea floor might be potential options for mitigating the environmental impact associated with discharge of the wharf runoff.

text: Environmental aspects of storm runoff discharge from a timber port, Tauranga, New Zealand An investigation was undertaken into storm runoff water quantity and quality, contaminant input to the receiving tidal waters from the Mt. Maunganui wharf, accumulation of potentially toxic resin acids in adjacent sediments, and the dilution of the wharf runoff in the receiving tidal waters, in order to assess the possible adverse environmental impact associated with the log operation at the Port of Tauranga Ltd.
Based upon field data and rainfall records, about a half of the annual precipitation over the log handling areas is converted to surface runoff (117,000 m³a⁻¹). Annual runoff volume per hectare of wharf surface is estimated as 7,500 m³ha⁻¹a⁻¹ for the sealed area and 3,700 m³ha⁻¹a⁻¹ for the gravelled area.
The optical quality of the wharf runoff is degraded due to addition of bark and soil particles. The black disk visual clarity (0.01-0.02 m) was only 0.5-1.0% of that in the receiving tidal waters. The wharf runoff appears very dark gray to yellowish brown in apparent colour (10YR1/3 to 10YR5/6 Munsell colour chart) and has a soluble yellow substance concentration of about 25 m⁻¹. Power relationships between the traditionally used parameters, for example, suspended solids and turbidity, were identified. The wharf surface pavement types had a significant influence on visual clarity, but little influence on yellow substance concentration.
The potentially toxic resin acids in the wharf runoff have been determined with SIM GC-MS. The average total resin acid level (1,030 ppb) is comparable to that of 1,000 ppb reported at which acute toxicity is likely to be exhibited. A relationship of resin acids against volatile suspended solids was established. Tests undertaken suggest that conventional treatment methods of natural sedimentation and flocculation-sedimentation are able to remove the resin acids effectively.
The levels of biological oxygen demand (BOD), total phosphorus and nitrogen in the wharf runoff are considerably higher than those of common urban runoff. However, the wharf runoff contributes little nitrate nitrogen and oil and grease to the receiving environment.
About 87,500 kg of suspended solids, 43,000 kg of volatile suspended solids, 14,200 kg of BOD, 500 kg of phosphorus, and 103 kg of resin acids are discharged to the Tauranga Harbour annually from runoff from the Mt. Maunganui wharf.
Analyses show that the impact on adjacent sediments from the storm runoff is limited to a distance of about 100 m from the discharge points and the resin acid levels in the sediments within this distance are not significantly higher compared to that of the storm runoff. The net resin acid accumulation rate in the shipping channel (Stella Passage) beside the log handling areas was estimated to be in the range of 300 to 370 ppb per year.
Based on field investigation and numerical simulations, the findings on dispersion and dilution of the wharf runoff in the receiving tidal waters are as follows: (i) the sea water around Stella Passage experiences an obvious natural salinity stratification, the extent of which depends greatly on the weather conditions; (ii) the wind drag stress and the pressure gradient caused by the addition of runoff had the greatest influence on the plume dynamics during the flood tide. The plumes basically remain within the top 2-3 m of the water column under different winds; (iii) the plume is unlikely to advect to the Whareroa Marae under strong (30-40 knots) easterly or northeasterly winds for a storm with a 5-year return period. However, there is an obvious influence on the Whareroa Marae under 30- 40 knot northerly winds; and (iv) the short duration and restricted region of the low dilution pulse of effluent around slack water may explain why there has been no reports of acute toxic events.
Sealing the gravel covered wharf area, improving the sweeping efficiency, and extending the present outfalls to the sea floor might be potential options for mitigating the environmental impact associated with discharge of the wharf runoff.

year: 1997

title: Integrating mātauranga Māori into community resilience frameworks for the built environment

authors: Dunlop, Ezra

abstract: Efforts to improve community resilience have seen universal efforts to grow capabilities in disaster management for the built environment. Although comprehensive frameworks exist, the perspective used to derive these frameworks fails to address marginalised communities' vulnerabilities, including the Indigenous Māori people. Colonisation and socio-economic deprivation of Māori mean community response frameworks fail to reflect their values and specific needs when preparing and responding to natural disasters.
The nature of Māori culture and values presents an opportunity to reimagine the scope of community resilience for an inclusive framework. The Māori history has resilient practices weaved into the very fabric of their culture through the oral transmission of waiata, whakataukī, whakairo, and pūrākau. The practice of community resilience amongst ancient Māori was not consigned to singular events but is a holistic perspective bound to their manner of living. Sourcing and qualifying this information from people aligned and immersed in nature is the knowledge required to improve the frameworks to respond to natural disasters while expanding the literature on community resilience.
This study collaborated with Ngāti Toa to represent the Māori worldview using tikanga Māori and Kaupapa Māori methodology in an action-based participatory research approach. The research analyzed traditional Māori resilience through wānanga and korero kanohi-ki-te-kanohi and evaluated various mātauranga, tikanga, and kaupapa that relate to the resilient nature of Ngāti Toa. Modern Māori perspectives of community resilience were compared to this information using a realistic earthquake scenario in the Wellington region. This led to expanding community resilience to be more inclusive of Māori communities and informed measures to enhance their resilience and address their unique needs following a disaster.
This study found that the Ngāti Toa community employs traditional resilience practices dating back to their migration to Aotearoa from Hawaiki. These practices are community-led and grounded in unity, with resilience being viewed as a collective responsibility. The study identified various Te Ao Māori resilience principles by translating traditional resilience principles into corresponding Te Ao Māori principles. A response and recovery plan was developed for Ngāti Toa in response to a realistic earthquake scenario. This plan includes a vulnerability matrix and a community resilience calculator to inform Ngāti Toa of their vulnerability level and needs following a disaster.
The community resilience frameworks developed for the Wellington region in response to the 7.5 magnitude earthquake were found to be economically dependent and did not utilize the response capabilities and strengths of Ngāti Toa. The frameworks lacked proper representation from Ngāti Toa and failed to address the needs of the Māori community in Wellington, resulting in inequitable outcomes. To rectify this,
Page | iii
community resilience frameworks for Māori should adopt a principle-based approach that supports collaborative engagement and integrates Māori cultural values. Unity is a crucial strength underpinning Māori resilience. Technological mediums such as retrofitting Marae should be developed to enhance Māori response capabilities and harness the strengths of Te Ao Māori resilience.

text: Integrating mātauranga Māori into community resilience frameworks for the built environment Efforts to improve community resilience have seen universal efforts to grow capabilities in disaster management for the built environment. Although comprehensive frameworks exist, the perspective used to derive these frameworks fails to address marginalised communities' vulnerabilities, including the Indigenous Māori people. Colonisation and socio-economic deprivation of Māori mean community response frameworks fail to reflect their values and specific needs when preparing and responding to natural disasters.
The nature of Māori culture and values presents an opportunity to reimagine the scope of community resilience for an inclusive framework. The Māori history has resilient practices weaved into the very fabric of their culture through the oral transmission of waiata, whakataukī, whakairo, and pūrākau. The practice of community resilience amongst ancient Māori was not consigned to singular events but is a holistic perspective bound to their manner of living. Sourcing and qualifying this information from people aligned and immersed in nature is the knowledge required to improve the frameworks to respond to natural disasters while expanding the literature on community resilience.
This study collaborated with Ngāti Toa to represent the Māori worldview using tikanga Māori and Kaupapa Māori methodology in an action-based participatory research approach. The research analyzed traditional Māori resilience through wānanga and korero kanohi-ki-te-kanohi and evaluated various mātauranga, tikanga, and kaupapa that relate to the resilient nature of Ngāti Toa. Modern Māori perspectives of community resilience were compared to this information using a realistic earthquake scenario in the Wellington region. This led to expanding community resilience to be more inclusive of Māori communities and informed measures to enhance their resilience and address their unique needs following a disaster.
This study found that the Ngāti Toa community employs traditional resilience practices dating back to their migration to Aotearoa from Hawaiki. These practices are community-led and grounded in unity, with resilience being viewed as a collective responsibility. The study identified various Te Ao Māori resilience principles by translating traditional resilience principles into corresponding Te Ao Māori principles. A response and recovery plan was developed for Ngāti Toa in response to a realistic earthquake scenario. This plan includes a vulnerability matrix and a community resilience calculator to inform Ngāti Toa of their vulnerability level and needs following a disaster.
The community resilience frameworks developed for the Wellington region in response to the 7.5 magnitude earthquake were found to be economically dependent and did not utilize the response capabilities and strengths of Ngāti Toa. The frameworks lacked proper representation from Ngāti Toa and failed to address the needs of the Māori community in Wellington, resulting in inequitable outcomes. To rectify this,
Page | iii
community resilience frameworks for Māori should adopt a principle-based approach that supports collaborative engagement and integrates Māori cultural values. Unity is a crucial strength underpinning Māori resilience. Technological mediums such as retrofitting Marae should be developed to enhance Māori response capabilities and harness the strengths of Te Ao Māori resilience.

year: 2023

title: Did the post-1986 decline in the homeownership rate benefit the New Zealand labour market? A spatial-econometric exploration

authors: Cochrane, William

abstract: The proportion of New Zealand households living in owner-occupied dwellings has declined steadily since the early 1990s. The unemployment rate declined steadily as well, except for upward shifts due to the late 1990s Asian Financial Crisis and the Global Financial Crisis a decade later. Research initiated by Andrew Oswald in the 1990s posits that declining homeownership and declining unemployment are linked and that the causality runs from high homeownership leading to high unemployment. The international empirical evidence for this hypothesis is rather mixed. In this paper, we revisit the issue with New Zealand census data for commuting-defined labour market areas from 1986 until 2013. Allowing for spatial spillovers in our data, we apply a general nesting spatial-econometric model. We also consider the potentially different impacts of freehold and mortgaged homeownership. Generally, the evidence that a declining homeownership rate contributes to a lower unemployment rate is statistically fragile. When statistically significant, an increase of 1% in freehold ownership appears to increase a labour market area’s unemployment rate by between 0.07 and 0.2% points. The effect is relatively stronger in those labour market areas where freehold ownership is still relatively low.

text: Did the post-1986 decline in the homeownership rate benefit the New Zealand labour market? A spatial-econometric exploration The proportion of New Zealand households living in owner-occupied dwellings has declined steadily since the early 1990s. The unemployment rate declined steadily as well, except for upward shifts due to the late 1990s Asian Financial Crisis and the Global Financial Crisis a decade later. Research initiated by Andrew Oswald in the 1990s posits that declining homeownership and declining unemployment are linked and that the causality runs from high homeownership leading to high unemployment. The international empirical evidence for this hypothesis is rather mixed. In this paper, we revisit the issue with New Zealand census data for commuting-defined labour market areas from 1986 until 2013. Allowing for spatial spillovers in our data, we apply a general nesting spatial-econometric model. We also consider the potentially different impacts of freehold and mortgaged homeownership. Generally, the evidence that a declining homeownership rate contributes to a lower unemployment rate is statistically fragile. When statistically significant, an increase of 1% in freehold ownership appears to increase a labour market area’s unemployment rate by between 0.07 and 0.2% points. The effect is relatively stronger in those labour market areas where freehold ownership is still relatively low.

year: 2020