Technical reports 2009

TR2009/001 - Assessment of trophic state change in selected lakes of the Auckland region based on rotifer assemblages
(529.9 KB PDF)

This report provides an assessment of the trophic state and trends of the seven lakes routinely monitored by the ARC. This assessment used an ecological indicator organism (rotifers) to infer the productivity of the lakes, thus allowing comparison with the water quality monitoring programme. The results of the two studies were similar with Lake Ototoa ranked as having the best water quality by both studies. Whilst the report indicates that six of the seven monitored lakes have degraded water quality, most of the lakes have shown no change over the duration of the study.

TR2009/002 - A survey of the riparian characteristics of the Auckland region
(289.9 KB PDF)

This report presents the results of a regional survey of the extent of fencing, vegetation types and stream bank erosion of riparian margins of rural streams in Auckland. The findings include that 25 per cent of rural streams have an effective fence on both banks, with similar amounts of fencing on streams in dairy and rural residential land uses.

TR2009/003 Whangateau Catchment and Harbour Study Review of Environmental Information for the Whangateau Harbour
(2.9 MB PDF)

This report provides an overview of the environmental conditions including geophysical characteristics, environmental quality, flora and fauna present in the Whangateau harbour. It identifies threats to this ecosystem and also identifies knowledge gaps which could be further investigated.

TR2009/004 Whangateau Catchment and Harbour Study Review of Environmental and Socio-economic information for the Whangateau Catchment
(789.0 KB PDF)

This report reviewed information relating to the Whangateau Catchment. The report highlights the Bio-Physical, Human Economic, Social Demographic, Planning factors, and future drivers for land use change and development relative to the catchments’ inherent values. GIS mapping and analysis has formed an integral part of these investigations, along with supporting literature and background reports.

Note: the electronic version does not include the appendices. A full electronic version including the map series is available on cd for purchase $10.00 or hardcopy $49.00.

TR2009/005 Whangateau Catchment and Harbour Study Review of Iwi and Stakeholder Information
(238.6 KB PDF)

This report outlines the issues and concerns of the various stakeholders who affiliate themselves with the Whangateau Harbour catchment. It contains findings from interviews of iwi, local community and government stakeholders with respect to the Whangateau harbour.

TR2009/006 Whangateau Catchment and Harbour Study Summary and Discussion Document
(937.1 KB PDF)

This report summarises the previous three studies’ information on the values of Whangateau, the perceived threats to those values and knowledge gaps. It provides a range of options for consideration as part of developing an implementation plan for the Whangateau including the development of a Whangateau forum.

TR2009/007 - An overview of soil quality in the Auckland region from 1995-2001
(179.1 KB PDF)

The ARC participated in two national soil quality monitoring initiatives in 1995–1998 and 1999–2001. This report reviews all the data and provides a summary of results. Eighty eight sites covering different soil and land use types: dairy pasture, sheep-beef pasture, horticulture, forestry, and indigenous vegetation were assessed against seven key soil quality indicators. On an area basis, about one third (38 per cent) of the monitored area met all the suggested soil quality targets. Indigenous forests and reserves had the highest proportion of sites (60 per cent) meeting the suggested targets, and dairy pastures the lowest (19 per cent).

TR2009/008 - Soil quality of horticultural sites in the Auckland region in 2008
(438.4 KB PDF)

Eighteen horticultural sites most at risk of soil quality degradation such as market gardens, arable cropping were resampled using the protocols established during earlier projects (1995-2001). Overall the current soil condition of these horticultural sites is similar to that observed in earlier sampling and remains of concern.

TR2009/009 Regional assessment of areas susceptible to coastal erosion
(1.4 MB PDF)

This report provides a regional overview of land susceptible to coastal erosion in the Auckland region.

TR2009/010 Natural hazards and their impacts (part 1)
(3.8 MB PDF)

This report provides a summary of natural hazards and their impacts in the Auckland region. The report broadly describes where natural hazards occur in the region and what the frequency and magnitude of these are. The types of consequences that might be encountered from the natural hazards identified are also discussed.

TR2009-010 Natural hazards and their impacts (part 2)
(2.8 MB PDF)

This report provides a summary of natural hazards and their impacts in the Auckland region. The report broadly describes where natural hazards occur in the region and what the frequency and magnitude of these are. The types of consequences that might be encountered from the natural hazards identified are also discussed.

TR2009/011 ARC LakeSPI
(2.9 MB PDF)

This report provides an assessment of the ecological condition of 32 lakes in the Auckland Region using an ecological index (LakeSPI) based on aquatic plants. The index scores ranged widely from 0 to 90 (on a scale of 0 to 100), with 6 lakes considered to be in excellent ecological condition (>60) based on this index. Of the 19 lakes with historical surveys with which to allow trend analysis, 7 lakes appeared to be stable, 6 improving and 6 declining. Only one lake was in a “pristine” condition. Comparisons with LakeSPI results obtained from around New Zealand showed that a high number of lakes in the Auckland Region have been colonised by the worst invasive aquatic weeds (Egeria, Hornwort and Lagarosiphon).

TR2009/012 - Changes in soil state and disturbance from 1999-2007
(350.1 KB PDF)

There has been a net decrease in stable, erosion-prone surfaces and a net increase in eroded and eroding surfaces between 1999 and 2007, up from 9 to 13 per cent of rural land. Most of the change is attributed to grazing pressure, cultivation and vegetation harvest.

TR2009/013 - Vegetation associated with land uses in the Auckland region
(195.5 KB PDF)

Nine broad uses (intensive, dairy, drystock, forest plantation, natural forest, natural scrub, exotic scrub, coastal grass and scrub, wetlands and mangrove swamps) are assessed for primary and secondary vegetation. Most land under rural use has a dense primary cover; highest for dairy pasture (76 per cent), next-highest for drystock pasture (72 per cent), somewhat lower for forest plantations (64 per cent) and intensive uses (59 per cent). Vegetation is not by itself an indicator of soil state, though extent to which it has been modified becomes relevant as an indicator of pressure on soil, from either land use or natural disturbance.

TR2009/014 - Vegetation soil conservation cover in the Auckland region
(181.4 KB PDF)

Two measures of soil conservation requirements are reported. Firstly the percentage of land that is stable with primary vegetative cover and secondly the extent of secondary dense, woody vegetation within the region.

TR2009/016 - Soil state in the Auckland region
(269.3 KB PDF)

This report summaries the analysis of 5277 one hectare sample areas spaced at 1km intervals across the Auckland region exposed soil surfaces. The sample survey results show that at 2007 3.3 per cent of the Auckland region is bare through some form of disturbance (land use or natural processes), which equates to 16,525 hectares.

TR2009/018 - Methods used to survey soil state in the Auckland region
(172.7 KB PDF)

This report summarises methods used for a point sample survey of soil state from 2007 region-wide aerial photography for the Auckland region. The report defines terms used in the point sample survey e.g. stable, erosion-prone, eroded and eroding, extensively disturbed; land use-related disturbance, natural disturbance, intact soil, disturbed soil, vegetated soil, bare soil, rural land use, non-rural land use.

TR2009/019 - Subtidal reef ecological monitoring 1999-2008 (part 1)
(3.5 MB PDF)

The Long Bay Marine Monitoring Programme was initiated in 1998 with the objective of detecting and documenting the impact of increased sedimentation associated with urban development on the subtidal marine environments of Long Bay. Results indicate that the subtidal biota has not been impacted in any significant way since the start of the monitoring programme.

TR2009/019 - Subtidal reef ecological monitoring 1999-2008 (part 2)
(3.2 MB PDF)

The Long Bay Marine Monitoring Programme was initiated in 1998 with the objective of detecting and documenting the impact of increased sedimentation associated with urban development on the subtidal marine environments of Long Bay. Results indicate that the subtidal biota has not been impacted in any significant way since the start of the monitoring programme.

TR2009/020 - Meola reef ecological monitoring 2001-2008
(4.5 MB PDF)

This report updates the results of the Meola Reef Monitoring Programme established in 2001.

TR2009/021 - Field analysis of chemicals of emerging environmental concern in Auckland
(2.4 MB PDF)

This report is an analysis of estuarine sediments, in the greater Auckland region, for metals and emerging chemicals of concern (ECCs). A list of 37 ECCs were investigated to cover the major classes of chemicals reported in a recent ARC review of organic ECCs (ARC Technical Report TR2008/028 Organic chemicals of Emerging Environmental Concern in Use in Auckland - Literature Review 1995-2005, Ahrens 2008), and included surfactants, flame retardants, plasticisers, estrogens, antifoulants and pesticides.

TR2009/022 - Soil erosion in Auckland’s hill country – A survey of fresh and recent erosion in 1999
(230.5 KB PDF)

This previously unpublished report presents findings from a survey of erosion on hill country soils in the Auckland region. The survey found that erosion is a natural phenomenon but the incidence varies with land use.

TR2009/023 - Rural land use on Aucklands soils – A survey of current land use in 1999
(275.5 KB PDF)

Findings from a survey of rural land use in Auckland are presented. Results of this previously unpublished survey confirmed the diversity of soil types and variety of land uses influences the sustainable use of soil resources in the Region.

TR2009/024 - Methods used to survey Auckland’s soil erosion – Hill country, sand country and rural land use in 1999
(296.4 KB PDF)

This report summarises methods used to survey soil erosion as reported in ARC Technical Reports TR2009/022, 023 and 025.

TR2009/025 - Methods used to survey Auckland’s soil erosion – Hill country, sand country and rural land use in 1999
(233.7 KB PDF)

This previously unpublished report presents findings from a survey of erosion on sand country soils in the Auckland region.

TR 2009/028 An assessment of the lengths of permanent, intermittent and ephemeral streams in the Auckland region
(1.3 MB PDF)

This report utilises a recent LiDAR survey of the Region to estimate the extent of streams. Previous estimates of stream length in Auckland were underestimating the actual number. This report updates our best estimate of stream length in the region to 16650km.

TR2009/035 - Fall velocities of stormwater sediment particles – literature review
(738.3 KB PDF)

This report documents a literature review of fall velocities of stormwater sediment particles, which is a key parameter in the design of stormwater treatment devices that use particle settling.

TR2009/036 - Mapping of impervious surface cover within the Auckland Region
(1.1 MB PDF)

Impervious surfaces can be roads, parking lots, roofs, compacted soil or compacted gravel. Such surfaces modify the surface hydrology, altering the flows and can change the physical and chemical properties of surface water. Impervious surfaces have been mapped for the greater Auckland metropolitan area for the years 2000 and 2008 and this report outlines the methods and results of the mapping.

TR2009/038 Erosion parameters for cohesive sediment in Auckland streams
(674.4 KB PDF)

This report documents field work undertaken in the Auckland region to assess Auckland-specific stream erosion parameters. Local parameter values are used to improve stormwater and stream management guidelines that will lead to a decrease in stream erosion.

TR2009/039 - Mahurangi Harbour Biological Monitoring Programme
(1.9 MB PDF)

This report provides information describing the data collected During the first year of monitoring in the Mahurangi Harbour for the period 1994 to 1995.

This report is part of a series of reports that were commissioned during the period 1993-1999 that were used to support the establishment of the Mahurangi Action Plan. They are being made available following a review of technical information.

TR2009/040 - Mahurangi Harbour Soft-Sediment Communities
(1.4 MB PDF)

This report describes baseline ecological data in the Mahurangi harbour and predicts the effects of harbour and catchment development on resident infauna.

This report is part of a series of reports that were commissioned during the period 1993-1999 that were used to support the establishment of the Mahurangi Action Plan. They are being made available following a review of technical information.

TR2009/041 - Mahurangi Estuary numerical modelling
(1.5 MB PDF)

This report describes the development and testing of computer models for the movement and circulation of water, the mixing processes and solute and sediment transport.

This report is part of a series of reports that were commissioned during the period 1993-1999 that were used to support the establishment of the Mahurangi Action Plan. They are being made available following a review of technical information.

TR2009/042 - Mahurangi land-use scenario modelling
(905.1 KB PDF)

This report describes the use of the BNZ catchment model to predict sediment erosion rates within the Mahurangi catchment and sediment delivery rates to the estuary for different land-use scenarios. Sedimentation rates within the estuary are then predicted using the estuary model.

This report is part of a series of reports that were commissioned during the period 1993-1999 that were used to support the establishment of the Mahurangi Action Plan. They are being made available following a review of technical information.

TR2009/044 - Ranking of Auckland soil’s susceptibility to degradation
(210.8 KB PDF)

This previously unpublished report provides background information used in the development of the ARC’s State of the Environment land monitoring programme.

TR2009/045 - Low impact design vs conventional development
(928.3 KB PDF)

This report addresses a literature review of developer related costs and profit for low impact design (LID) versus conventional development approaches. Costs are limited to examination of construction costs. Other economic cost methods include life cycle cost analysis and benefit-cost analysis, which are not contained in this report.

TR2009/046 - Contaminant Accumulation in the Open Coastal Zone
(238.8 KB PDF)

This study provides an overview of sediment settling characteristics from urban stormwater discharging to an open coastal environment and provides recommendations for monitoring the effects of stormwater discharging to that environment.

This report is part of a series that were commissioned to characterised urban stormwater discharges.  The reports were used to support the establishment and ongoing operation of the Regional Discharges Project.

TR2009/047 - Modification of the Model to Assess Ecosystem Health Using Benthic Communities
(72.5 KB PDF)

This report describes modifications made to the Benthic Health Model developed in 2002 to assess the ecosystem health of marine benthic communities.

This report is part of a series that were commissioned to characterised urban stormwater discharges.  The reports were used to support the establishment and ongoing operation of the Regional Discharges Project.

TR2009/048 Benzene,1, 3 Butadiene and Other VOCs in Auckland
(1.3 MB PDF)

This report summarises hydrocarbon measurements that have been undertaken in Auckland over the past 10 years.

TR2009/050 - Sediment Quality Guidelines for the Regional Discharges Project
(429.1 KB PDF)

This report evaluates a series of possible guideline values for managing contaminants in sediment in marine receiving environments within urban or peri urban catchments.

This report is part of a series that were commissioned to characterised urban stormwater discharges.  The reports were used to support the establishment and ongoing operation of the Regional Discharges Project.