Status evaluation is measured in relation to scientifically based and commonly agreed sub-basin specific threshold values, which define the values that should not be exceeded (Thresholds and Status evaluation figure 1).
Thresholds and Status evaluation figure 1. Schematic representation of the threshold value applied in the water clarity core indicator, the threshold values are assessment unit specific (see Good environmental status table 1).
These indicator threshold values were based on the results obtained in the TARGREV project (HELCOM 2013a), taking also advantage of the work carried out during the EUTRO PRO process (HELCOM 2009) and national work for EU WFD. The final threshold values were set through an expert evaluation process done by the intersessional activity on development of core eutrophication indicators (HELCOM CORE EUTRO) and the targets were adopted by the HELCOM Heads of Delegations 39/2012.
Thresholds and Status evaluation table 1. Assessment unit specific threshold values for the water clarity core indicator.