Mika Marttunen Anne-Marie Hagman Multicriteria decision analyses with Web-HIPRE in lake restoration projects Mika Marttunen Anne-Marie Hagman

Backround Several thousand lakes needs restoration. Hundreds of iniatives of restoration projects to the Regional Environment Centers Need to create a method which provides a systematic and transparent way to prioritize these initiatives and to identify those lakes which need restoration and where opportunities for the successful outcome are highest. A multi-criteria decision analysis approach is currently being developed in the Finnish Environment Institute for the systematic comparison of the lakes. 18.4.2019

Main phases: 1. Choosing the objectives and attributes for the comparison. Two main value trees have been developed for that - State of the lake - Recreational and nature values of the lake 2. Assessing the performance of each lake in respect to each attribute 3. Defining the relative importance of the attributes 4. Calculating priorities for each lake by using Web-HIPRE model 5. Analysing the results and drawing diagrams and other figures 18.4.2019

Testing Web-HIPRE-model in the Mäntsälä community Preliminary results of 6 lakes are presented here Recreational and nature values and ecological status of each lake has been calculated with the Web-HIPRE-model Two priority values for each lake Plotting these priorities helps to analyse the differences in the status and the use of the lakes 18.4.2019

Assessment of status of the lake A simplified example of the value-tree used in the analysis Assessment of status of the lake goal objectives Water quality Macrophytes Fishstock species coverage Catch/ area CPUE Tot.P Chlor-a criteria alternatives Lake 3 Lake 1 Lake 2 18.4.2019

Weights of the criteria in defining state of lakes in Mäntsälä:   Ranking Points Normalized weight Water quality 1 100 0,23 Macrophytes 3 80 0,18 Sediment Blooms of algae 2 Fishstock The most important criterion in this assessment has got 100 points, others 100 or less depending on their relative importance compared to the best one. 18.4.2019

Fish stock kirjoitetaan erikseen! The priority values for the ecological status of Mäntsälä lakes. The higher the priority value the poorer is the condition. Fish stock kirjoitetaan erikseen! 18.4.2019

The priority values for the recreational use of Mäntsälä lakes The priority values for the recreational use of Mäntsälä lakes. The higher the value, the higher is the use of lake. 18.4.2019

The result of the analyses: Comparison of Mäntsälä lakes with respect to recreational use and state High need for restoration No need for restoration 18.4.2019