20. Open Space 4 Zone Volume Two only vegetation removed. Any vegetation removed under this Standard must only be cleared by non-mechanical means. 20.3.5.4. All trees must be felled away from a river (except an ephemeral river, or intermittently flowing river when not flowing), lake or Significant Wetland. 20.3.5.5. No tree or log must be dragged through the bed of a river (except an ephemeral river, or intermittently flowing river when not flowing), lake or Significant Wetland. 20.3.5.6. Wheeled or tracked machinery must not be operated in or within 8m of a river (except an ephemeral river or intermittently flowing river, when not flowing), lake or Significant Wetland. 20.3.5.7. Within 6 months of completion of vegetation clearance, a suitable vegetative cover that will mitigate soil loss must be restored over 80% of the clearance site. 20.3.5.8. The depth of topsoil removed must not exceed more than 20mm over more than 15% of any vegetation clearance site. 20.3.5.9. No woody material of greater than 100mm diameter must be left in a river, lake or Significant Wetland. 20.3.5.10. Vegetation clearance must not cause any conspicuous change in the colour or visual clarity of a flowing river after reasonable mixing, or the water in a Significant Wetland measured as follows: (a) hue must not be changed by more than 10 points on the Munsell scale; (b) the natural clarity must not be conspicuously changed due to sediment or sediment laden discharge originating from the vegetation clearance site; (c) the change in reflectance must be <50%. 20.3.5.11. If the clearance is of indigenous vegetation, the following also applies: (a) no more than 500m 2 of indigenous sub-alpine vegetation must be cleared in any 5 year period; (b) no more than 100m of tall tussock of the genus Chinochloa must be 2 cleared in any 5 year period. 20.3.6. Application of a vertebrate toxic agent into or onto land. 20.3.6.1. The agent must be approved for use under the Hazardous Substances and New Organisms Act 1996 and the use and discharge of the substance is in accordance with all conditions of the approval. 20.3.6.2. The discharge must be by the administering agency, or by any person authorised by the administering agency to carry out the activity, or by any other agency carrying out statutory powers in relation to the activity. 20.3.6.3. All reasonable care must be exercised in the discharge so as to ensure that the vertebrate toxic agent must not pass beyond the legal boundary of the area of land on which the vertebrate toxic agent is being discharged. 20.3.6.4. The discharge must not result in the vertebrate toxic agent being deposited on any roof or structure used as a catchment for water supply. 20.3.7. Discharge of contaminants to air arising from burning in the open. 20.3.7.1. Only material generated on the same property must be burned. 20 – 4