Volume One 15. Resource Quality (Water, Air, Soil) Management of non-point source discharges [RPS, R, C] Policy 15.1.25 – Recognise that, in many situations, non-regulatory methods will be an effective method of managing the adverse effects of non-point source discharges. Non-point source discharges are diffuse in nature as they do not enter the environment at a discrete point. Most non-point source discharges are the result of run-off where rain water picks up contaminants such as sediment, nutrients, toxicants and pathogens from land. It is also possible for some of these contaminants to leach into underlying groundwater through infiltration. As such, any non-point source discharge (effectively contaminated runoff) is a consequence of particular land use activities. The diffuse nature of non-point source discharges means that they are inherently more difficult to manage as there is no particular point such as an outfall to which treatment or management can be applied. For this reason, the main approach to addressing the adverse effects of non-point source discharges over the life of the MEP will be to work with landowners to improve land use practices to minimise the potential for run-off. In time and as signalled in Policy 15.1.3, the Council will establish cumulative contaminant limits to assist with the effective management of the adverse effects of all discharges to freshwater within a catchment. These limits will be established as regional rules and will establish a maximum amount of resource use within a catchment for water quality outcomes. [R, C] Policy 15.1.26 – Encourage, in close association with rural industry groups, the use of sustainable rural land management practices. All of Marlborough’s established rural land uses have industry groups to represent the interests of their members. The Council’s focus on implementing non-regulatory methods will be to work with and through these established industry groups to co-operatively promote and encourage sustainable rural land use practices. The Council may also undertake joint investigations with rural industry groups to gain a better understanding of the impact of particular rural land use activities on water quality. [R, C] Policy 15.1.27 – Promote the retirement and planting of riparian margins in rural areas to intercept contaminated runoff, especially where water quality is degraded or at risk of degradation. Riparian margins are those areas of land adjoining surface waterbodies or coastal waters. The retirement of riparian margins from productive use creates a physical buffer between the effects of rural land uses and adjoining rivers, lakes, wetlands and coastal waters. This buffer reduces the potential for contaminated runoff to reach these waterbodies and coastal waters. On properties where stock is intensively grazed, riparian retirement may require fencing to prevent stock entry to the riparian margin. The effect of riparian retirement is enhanced when the retired margin is planted, as vegetation will intercept many contaminants present in runoff (e.g. nutrients and sediment). Tall riparian vegetation further improves water quality by reducing water temperature and algal growth. For these reasons, the Council will actively promote the retirement and planting of riparian margins as a sustainable rural land management practice. Note that Policy 8.2.11 of Chapter 8 - Indigenous Biodiversity promotes the planting of indigenous vegetation in riparian margins and other areas. The positive effects of retiring and planting riparian margins will be greatest where the quality of water in rivers that flow through rural environments is degraded or at risk of degradation. These rivers are identified in Tables 15.1 and 15.2. The Council operates and maintains an extensive drainage network on the Lower Wairau Plains that acts to reduce water table levels over what is now some of the most productive land in 15 – 23