Wairau/ Awatere Resource Management Plan 14.2.4 Effects on Land Productivity The soil’s productivity depends on its friability and drainage and on its fertility. Burning can strip nutrients from the land or expose the soil to accelerated erosion. Mechanical land clearance e.g. bulldozing, can remove topsoil, mix topsoil with subsoil, or compact the soil so that it is no longer free draining or well aerated. 14.2.5 Soil Conservation Reserves 14.2.5.1 Wither Hills The Wither Hills immediately south of Blenheim have particularly high erosion potential due to the nature of the soil. The consequences of rapid erosion filling stream channels results in flood overflows at the base of the hills with water flowing directly into intensively developed residential areas of south Blenheim. In recognition of the severity and consequences of this erosion problem some 1000 hectares of the Wither Hills in four catchments have been acquired over 50 years into public ownership and are held by the Council. Soil conservation works have been carried out on the land and the land continues to be managed and maintained to minimise soil erosion. There is no doubt that this work is vital to the safety of Blenheim. In 1993 the Council prepared a management plan for the Wither Hills setting out in detail its intentions to run it as a farm park to achieve soil conservation aims while providing recreational values and some farm income. 14.2.5.2 Wye Catchment Reserve Previous authorities have carried out considerable soil conservation works on the Wye Catchment, not only because of the heavily eroded state of that catchment, but as a trial for methods that can be used elsewhere. What is practical to be done has been done and there is little to be gained at present from further pro active soil conservation measures. It is also acknowledged that the existing stands of Pinus Contorta present a seed source for spread of wilding trees and that there is a need for control measures to limit the spread of these trees. 14.3 Objectives and Policies Objective 1 The avoidance, remediation or mitigation of the adverse effects of inappropriate land use practices, including those which give rise to loss of those desirable physical, chemical and biological characteristics of soils which enable them to retain their life supporting capacity and to sustain plant growth increased sedimentation of surface and coastal waters, increased risk of erosion and damage to natural and/or iwi values. Policy 1.1 Encourage wise land use practices that will avoid, or mitigate the adverse effects of land disturbance and soil erosion. Policy 1.2 Avoid land use practices that increase the potential for accelerated stormwater runoff. 14 - 2