3. Environmental Setting

This section of the AQ DWP describes the environment surrounding the main works site in terms of meteorological influences on the transport of air contaminants and sensitivity of adjacent activities to those discharges.

3.1 Site Description

The main works will be undertaken near the existing Mt Eden Station and along the NAL, in an existing urban environment. The main works area is generally bounded by the NAL (south), State Highway 1 (east), Dominion Road (west), and Nikau Street (north) (refer Figure 3-1). The main works will include construction activity along Nikau Street, Ruru Street, Porters Avenue, Fenton Street, Haultain Street, Ngahura Street, Flower Street, Shaddock Street, Mt Eden Road, Normanby Road, Boston Road and Nugent Street.

Additional areas of land outside the CRL designation boundaries may also be required to provide construction access to the NAL corridor.

CRL Designation 2500-6 KiwiRail Designation 6300

Figure 3-1: Site and extent of main works

3.2 Meteorology

Figure 3-2 shows wind roses of wind speeds and directions measured at the NIWA weather station at the Auckland Museum of Transport and Technology (MOTAT), Western Springs over year round, summer (December to February) and winter (June to August) periods.

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The weather station is located approximately 2.85 km to the west of the CRL Mt Eden site. Wind measurements at this station are considered to be generally representative of conditions over the Auckland isthmus as it is relatively free from nearby obstructions or eddies created by adjacent buildings.

Although localised topographical features and adjacent buildings at the Mt Eden site are likely to alter wind conditions, the wind direction frequency trends illustrated below are likely to be broadly similar to those experienced at the site.

Based on the wind roses in Figure 3-2, winds are predominantly from the southwest and northeast, and therefore sensitive locations to the northeast and southwest of the site, respectively, are likely to be most frequently exposed to any off-site dust emissions from site activities. The amount of dust generated is also highly dependent on whether conditions are dry, and the wind speeds, with faster wind speeds increasing effect of wind erosion and the distance that the dust travels.

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All months, 2016-2019, Calms = 5.52%

Winter months, 2016-2019, Calms = 6.28% Summer months, 2016-2019, Calms = 2.25%

Figure 3-2: Wind rose frequency analyses of wind speeds and directions at the Auckland MOTATweather station for August 2016 to August 2019, year round, winter and summer months. Source: NIWA Cliflo database.

Figure 3-3 shows that the expected drier months are during summer, when wind speeds also tend to be higher. Summer winds are dominated by a south-westerly wind which will transport any emitted dust towards sensitive receptors to the northeast of site.

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Figure 3-3: Percentage of wet days (rain exceeding 1 mm) over each month of the year at MOTAT. Source: NIWA Cliflo database.

3.3 Sensitive Receptors

The main works are situated within a ‘business –mixed use zone’. Neighbouring zones include residential (single house and mixed housing urban and suburban), open space (conservation and informal recreation) and more business (including city centre). Adjacent land use therefore comprises a range of commercial, residential, and recreational activities. Due to the density and nature of development and human occupation in surrounding areas the sensitivity of the local environment to air pollution in general is relatively high.

Examples of nearby activities that may be sensitive to dust and other air contaminants include:

Residential apartments such as on Flower Street, Nikau Street, Fenton Street, Ngahura Street, Korari Street, Akiraho Street, Enfield Street and Normanby Road. Residential houses such as those along Akiraho Street, Ruru Street and Sylvan Avenue. Education centres such as the Bear Park Early Childcare Centre at the western end of Akiraho Street. Pedestrian access (to offices and other places of work) and parked vehicles along roads. Bars and restaurants, particularly where premises include outdoor dining or entertainment areas. Retail, office and commercial premises. Cityside Baptist Church, Mt Eden Road. Mt Eden Prison.

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