Volume One 5. Allocation of Public Resources This policy assists decision makers to determine the appropriate duration of water permits. The circumstance in (a) reflects a desire by water users for longer water permit terms in order to provide the certainty required to make long-term investment decisions. It also recognises that there is certainty regarding the sustainability of water abstraction from a FMU when limits are set by rules in the MEP. In this circumstance, durations of 30 years are generally considered appropriate. The circumstances in (b) and (c) reflect situations where there is uncertainty regarding the sustainability of abstraction, either because the resource is over-allocated or because there is a lack of knowledge to set specific environmental flows/levels. A shorter term is an effective means of managing this uncertainty as it allows the sustainability of the existing abstraction to be reassessed against the provisions of a reviewed MEP after its current ten year life. The policy also recognises that there may be other factors involved with a specific proposal that influence the determination of appropriate duration. [R] Policy 5.3.15 – Require land use consent for the planting of new commercial forestry in flow sensitive areas. Afforestation of land currently in pasture has the potential to reduce water yield in the relevant catchment with consequential effects on the surface water hydrology. Water permits have been granted through the provisions of the MEP and through previous planning documents, with reliabilities based on historical surface water hydrology. If water yield is reduced by afforestation in the long-term, it creates the potential to reduce the flow reliability that water users have come to depend upon. This could mean that water users become subject to restrictions more frequently than they have been to date. The water resources most at risk are south of the Wairau River and specific Afforestation Flow Sensitive Sites are identified. The identified land receives low rainfall (in comparison to north of the Wairau River) and contributes runoff to smaller catchments. These factors make the water resource supplied by runoff from the land more vulnerable to changes in water yield. The policy does not apply to existing commercial forestry or the replanting of that forest following harvest, as the effects of this forestry on water yield are part of the existing environment. [R] Policy 5.3.16 – When considering any application for land use consent required as a result of Policy 5.3.15, have regard to the effect of the proposed forestry on river flow (including combined effects with other commercial forestry and carbon sequestration forestry (non- permane nt) established after 9 June 2016) and seek to avoid any cumulative reduction in the se ven day mean annual low flow of more than 5%. The policy provides guidance to determine land use consent applications required as a result of Policy 5.3.15. The threshold protects the reliability of supply for existing water permit holders by limiting the extent of flow modification. The effects of reductions in water yield on reliability are greatest at times of low flow and for this reason the seven day mean annual low flow is used in the policy. It is also important that any assessment of environmental effects considers the cumulative effects of afforestation within a catchment and any opportunities for adverse effects on water yield to be remedied or mitigated. The establishment of commercial forestry prior to the notification of the MEP was permitted in most situations under the provisions of the previous Wairau/Awatere Resource Management Plan. Any reduction in flow shall be measured against the seven day mean annual low flow at 9 June 2016, being the date of notification of the MEP, and any assessment of cumulative effects should only consider commercial forestry established after 9 June 2016. 5 – 17