Volume One 15. Resource Quality (Water, Air, Soil) Groundwater is the source of drinking water for most of Marlborough’s towns and small settlements. This policy establishes controls on activities that could result in groundwater becoming unsafe for consumption as a result of the leaching of contaminants into groundwater. The vulnerability of aquifers to leachate contamination is determined by the depth of the aquifer and the permeability of the overlaying soil. Any area of land above an aquifer considered to be high risk has been mapped in the MEP as a Groundwater Protection Area. Within this area, change of land use to activities likely to generate leachate should, where practicable, be avoided. Where it is not considered possible to do so, provision must be made to contain the leachate generated. The groundwater beneath existing land uses will also be monitored. Where land use in the area is observed to be adversely affecting groundwater quality, actions may be required to avoid the effect in the future. The discharge of contaminants and excavation within groundwater protection areas will also be regulated to avoid any adverse effect on groundwater quality. Collectively, the controls implemented through this policy will assist to protect the health and wellbeing of communities that rely on groundwater as a source of drinking water. [R, C] Policy 15.1.31 – Recognise that disturbing the seabed or the wet bed of a lake or river results in a discharge of sediment that has the potential to cause adverse effects on water quality. Sections 12 and 13 of the RMA regulate the activity of disturbing the seabed and the bed of lakes and rivers, respectively. This disturbance usually releases sediment into water, effectively a non- point source discharge of contaminants. To ensure integrated management of the effects of bed disturbance, this policy signals that any water quality effects caused by such a discharge also need to be managed. [R, C] Policy 15.1.32 – In considering any resource consent application for the disturbance of a river or lake bed, or the seabed, or land in close proximity to any waterbody, regard will be had to: (a) whether the disturbance is likely to result in non-compliance with the clarity standards set for the waterbody, after reasonable mixing; (b) in the event of possible non-compliance with the clarity standards set for the waterbody, after reasonable mixing: (i) the purpose for undertaking the disturbance and any positive effects accruing from the disturbance; (ii) the scale, duration and frequency of the disturbance; (iii) the extent to which the bed disturbance is necessary and adverse water quality effects caused by the disturbance are mitigated; and (iv) for freshwater, the potential effects of increased turbidity on the values of the waterbody set out in Schedule 1 of Appendix 5 of the Marlborough Environment Plan or on the natural character values of the coastal environment in relation to water quality as set out in Appendix 2 of the Marlborough Environment Plan. The construction, placement, maintenance and repair of structures and the installation and maintenance of water intakes, gravel extraction, dredging, flood and coastal protection works activities can all result in disturbance of river, lake and seabed. As well as bed disturbance, activities along the margins of waterbodies can generate sediment that has the potential to enter the water and adversely affect water quality. Water quality standards for turbidity and clarity established throughout this chapter for waterbodies are the appropriate starting point for the consideration of any adverse effects of disturbance on water quality. Where these water quality standards are not likely to be met, it is important that all of the circumstances of the disturbance be considered. Matters under (b) of the policy provide guidance on these circumstances, allowing the relative significance of any adverse effects on water quality to be assessed when determining 15 – 25