Förstudie för skapandet av ett miljöövervakningsprogram : en styrkeanalys angående vattendrag i västerhavets vattendistrikt för fastställandet av provantal i tid och rum för ett effektivt omdrevsprogram

Sammanfattning: The environmental monitoring in Sweden has been developed by several different parties and is now being coordinated and made more effective in order to meet the current demands on high quality information regarding the state of the environment. Sweden has been divided into five different water districts based on watershed areas because of requirements in the Water Directive of the EU. In Sweden there are two common types of environmental monitoring programs used to gather information on changes in time and in space. Currently both these two types are used for lakes in the water district of the western sea but only one is used for watersheds. The purpose of this report is to supply basic information regarding the possible need for a second environmental monitoring program for watersheds in order to better describe the spatial variation within the district as well as to determine the number of samples necessary in order to describe the district over time and space. By using data from the current monitoring program for watersheds a simulation of a second monitoring program has been made using a specific group of variables. The variance in the selected data was then analysed in order to extract variance components. With the variance component explained by time and space a power analysis was performed in order to find out how many samples were needed. A larger number of samples were needed in order to detect a change from one watershed to another compared to that needed to describe change over time. It is a requirement that the entire water district be classified and therefore possible that a second monitoring program will be required, but further studies would have to be done in order to determine this.