Chapter 13 - Soil Conservation 13.0 Soil Conservation 13.1 Introduction The land ecosystems of Marlborough are composed of mountains, hills, valleys and plains and the life systems contained within them. They include the plants, animals and organisms which inhabit and form part of those ecosystems. The land ecosystems are intimately linked with the fresh and coastal water ecosystems of the Marlborough Sounds area. Under the Act the Marlborough District Council, amongst other things, has statutory responsibility to control the use of land for the purposes of soil conservation. The Act provides that no person may use any land in a manner that contravenes a rule in the Plan unless a resource consent is obtained. The corollary to this is that land uses are permitted unless controlled by the rules in the Plan. In the context of the Marlborough Sounds Resource Management Plan the Council seeks to: Protect land resources from the adverse effects of land uses and activities (for example, maintain the life-supporting capacity of soil by minimising erosion resulting from land-based activities); and Enable people and communities, including future generations, to use land resources provided their activities do not prevent the sustainable management of land and water resources. 13.2 Issue Effects from land use activities that cause a reduced life-supporting capacity of soils, reduction to the natural and cultural values of the land, or increased likelihood of erosion, flooding or material in water. Soil retention is the first step to maintaining the life-supporting capacity of the land, and maintaining the quality of fresh water within the Pelorus, Rai and Kaituna Rivers, and coastal water within Pelorus and Queen Charlotte Sounds. Soil that has been cleared of vegetation can become exposed to the erosive forces of rain, wind and frost. If at the same time the soil has been loosened by cultivation or excavation it is more easily eroded. Eroded soil moves downhill or is blown by the wind and will eventually find its way into the rivers or Sounds, causing sedimentation. There are, however, situations where land disturbance is an essential component of the sustainable management of a resource, for example the clearance of existing drainage systems. The effects of this form of land disturbance are minor and the benefits significant provided that care is taken to ensure that the likelihood of erosion, flooding or material in water is minimised. Sedimentation can cause damage to marine and freshwater ecosystems, and may reduce the water quality. Excavation can destabilise hill slopes, particularly on steep hills. When combined with high rainfall, excavation can cause erosion. 13 - 1