Volume Two 21. Floodway Zone (a) mobile machinery used for a limited duration as part of farming activity occurring in the Floodway Zone; (b) a fixed motor or equipment, frost fan or gas gun, milling or processing forestry activity, static irrigation pump; or motorbike that is being used for recreational purposes. 21.2.2.4. Noise must be measured in accordance with NZS 6801:2008 Acoustics – Measurement of Environmental Sound, and assessed in accordance with NZS 6802:2008 Acoustics – Environmental Noise. 21.2.2.5. Construction noise must not exceed the recommended limits in, and must be measured and assessed in accordance with, NZS 6803:1999 Acoustics – Construction Noise. 21.2.3. Odour. 21.2.3.1. The odour must not be objectionable or offensive, as detected at or beyond the legal boundary of the area of land on which the permitted activity is occurring. 21.2.4. Smoke. 21.2.4.1. The smoke must not be objectionable or offensive, as detected at or beyond the legal boundary of the area of land on which the permitted activity is occurring. 21.2.5. Dust. 21.2.5.1. The best practicable method must be adopted to avoid dust beyond the legal boundary of the area of land on which the activity is occurring. 21.2.6. Dust from any process vent or stack. 21.2.6.1. The dust must not contain hazardous substances. 21.2.6.2. The particulate discharge rate from any air pollution control equipment and dust collection system must not exceed 250mg/m at any time, corrected to 0°C, 3 1 atmosphere pressure, dry gas basis. 21.2.6.3. Dust particles must not exceed 0.05mm size in any direction. 21.3. Standards that apply to specific permitted activities 21.3.1. Maintenance or reconstruction of a stopbank that is structurally weak, damaged or that has developed isolated low points. 21.3.1.1. A stopbank must only be reconstructed up a maximum of the 1 in 100 year design height. 21.3.1.2. Works must be undertaken outside of the wet part of the riverbed. 21.3.2. Rock or gabion structural bank protection works. 21.3.2.1. Rock may be used for protecting a river bank edge, training bank or stopbank. 21.3.2.2. Rock from a damaged or redundant structure may be recovered from the riverbed. 21.3.2.3. A continuous length of vertical gabion bank wall exceeding 50m must be avoided by interposing some gently sloping sections for bird access. 21 – 3