LST N131 Risk local impact associated buildings — GIS support for small sewers

Reliable and nationally comprehensive data on the geographical location of individual drinking water wells are currently lacking. In order to assess the risk of impact on individual drinking water wells, the risk is assumed to increase with density between residential buildings. The same definition for contiguous settlements is used for nitrogen as for phosphorus, the more houses the higher the risk score. The purpose of the GIS support is to create conditions at a national level for a reasonable, legally certain and more consistent assessment of the level of protection under Chapter 2, Section 3 of the Environmental Code when examining small sewers. The GIS support consists of maps showing the risk of impact on recipient/exposure point due to load from a drain. The maps have been produced through risk assessments based on the legislator’s instructions on criteria for assessing the high/higher level of protection for the entire surface of Sweden.