Predicting change in lake ecosystems

Jönköping County, a lake rich region, has many deep lakes that create ecological niches for cold water species. Jönköping county administrative board has the role to preserve and improve water quality and the aquatic ecosystems. In their work there is a need for knowledge, especially quantifications, on how climate change impact lake properties such as water temperatures and ice coverage.

This case study looks at how water temperature and ice coverage change for a few lakes in Jönköping County. Changes in air temperature, retrieved from the SWICCA demonstrator, are used in lake model-simulations to find how climate change affects physical properties in lakes – that in turn affect cold water species.

Some of the results will be part of the County’s environmental monitoring.

Read recent progress here!

An example of fish in an aquatic ecosystem

Changing fish habitats under climate change.  Salvelinus umbla, also known as lake char, taken by Klas Balkhed (County Administrative Board in Jönköping)

Case Study Description
Data Description
Reference information

Water-management issue to be addressed

Climate change affects different aspects of water quality and the ecological status of lakes. In the work with the EU-WFD as well with the responsibility to preserve the natural resources in the region, Jönköping County need data to understand the impact of climate change. In this SWICCA-project we look at how changes in air temperature affect the water temperature, ice cover and stratification patterns at some chosen lakes. All these indicators have impact on the biological, physical and chemical status.

Decision support to client

The results from the case will be used:

  • in decisions regarding measures for preserving fishes, especially cold water species. More specific in decisions regarding where to prioritize work with blue infrastructures such as fish ladders, changes in dams and culverts
  • in the work with the EU WFD
  • to give Jönköping county an indication on how a warmer climate will impact different type of lakes in the county. This information will be used in the exercising of authority, for example giving permission for business, state supervision and for future planning.

The results will also be used in evaluation of environmental monitoring. Results will be saved in databases together with other local data and shared within the county as well as with municipalities.

Value added by climate impact indicator:

  • Quantification of how water temperature will change in a future climate.
  • Contributing in the decision process in questions affected by, or affecting water temperature. For example permissions for industries or in the management of dams.
  • Evaluation of environmental monitoring data.
  • Easy access to experts (on a personal level) in the field of using indicators in decision making.
  • Increase knowledge in general about climate change.

Temporal and Spatial Scale

Jönköping County need to assess changes monitored in the environment and how closely the changes are related to climate change. The county is also working with planning and permissions to for example industries and hence need to consider climate change in a longer time frame. The temporal scale is from today to 50 years ahead.

The spatial scale is limited to Jönköping County (10 000 km2) and to catchment area affecting the lakes in Jönköping county. Small scale phenomena will also be included (1 km2) 

Knowledge Brokering

Jönköping County administration is an active client and is eager to follow the project with meetings around 3-4 times per year but with more frequent contact over email and telephone. The project has been performed with an agile approach where method and results have been delivered and evaluated continuously. Jönköping County has given feedback on methods and results to produce as useful results as possible.

Parts of the results are presented at local conferences in Jönköping. Data will be shared in simple data format to make it accessible for everyone involved. Results will also be published in a report.

Climate Impact Indicators

Pan-European Indicators

Primarily, indicators for Temperature (air) and Relative humidity have been downloaded to change local historical data for lake model simulations. The SWICCA indicator “Water temperature” will also be downloaded and compared with lake model results for specific lakes. The SWICCA-indicator will be used to visualize change in lake temperature in a more general aspect but for a larger area than for the specific lakes investigated in this case. 

Local indicators

Local indicators might be developed with local environmental data.

Pan-European data to local scale


Step 1: Climate indicators are collected from the SWICCA demonstrator as input to lake model. Indicators are changes in air temperature, cloud cover and relative humidity.

Step 2: Local data on lakes is gathered to run lake model for some lakes chosen by client. Data include driving data (air temperature, wind, cloud cover and relative humidity). Set up data is hypsography and physical parameters such as water transparency. Calibration data is water temperature at different depths and ice coverage. Client also asked for local historical climatological data to use for a later step, the environmental analysis.

Step 3: Lake model is run for a selection of lakes in Jönköping county. Indicators are produced: mean temperature at surface, mean temperature at bottom, change in the thermocline, days per year with temperature above 15 and 20 degrees, days per year with ice cover and days per year with a summer thermocline.

Step 4: The results from the lake model as well as local climatological data is analyzed together with local environmental data in order to find patterns and assess changes in environment, especially changes in fish availability, due to climate change. Combined Impact Indicators might be developed.

Step 5: The indicator water temperature are extracted from the SWICCA demonstrator and is analyzed with results from the local lake model.  If this falls out well, the SWICCA- indicator temperature will be used for catchments not investigated with the lake model.

Step 6: Maps over Jönköping County are produced to visualize results.

Step 7: The information is used in sustainable planning with better prioritized decisions about for example which aquatic species to protect, and in building green / blue infrastructure.

Lessons learnt

An initial plan was to download global indicators showing water temperature, ice cover and if possible indicators regarding the stratification produced with a hydrological model. After discussion with the client, Jönköping County, it got clear that it is of value to deliver impact indicators that could be verified with local observations. Global indicators would not be possible to verify with observations. Instead specific, by client chosen lakes was chosen to be investigated with a local lake model. To drive the lake model, global indicators was used.

With the new strategy it was very easy and clear to download indicators since the SWICCA demonstrator both displayed metadata as well as information and tutorials regarding climate indicators.

Multiple results from other projects – a possible problem?

Similar indicators as produced in this project (lake temperature, ice coverage) will be produced for another lake in Jönköping County. In that project fewer GCMs and RCMs will be used. Also only two RCPs will be used instead of three as in SWICCA. To communicate the different input data and possibly different results for the two projects will be very important.

Importance and Relevance of Adaptation

Jönköping County plays an important role in many different activities regarding water management. Climate change is a factor that is vital to include in future planning, state supervision, permission and environmental monitoring. With the new knowledge from this case study, Jönköping County will have improved knowledge when climate change have a crucial impact, or if their focus should be on other aspects of water management.

With the results and indicators provided by this project they will have better decision support on how to preserve cold water fish species.

Another aspect of adaptation is to get the right information for timing of sampling. From this project, Jönköping county will get the dates when the lake is the most stratified, an important time for temperature measurement. It is possible that the strongest stratification will occur later in autumn in the future, and this is important to consider in monitoring programs.

Pros and Cons or Cost-Benefit analysis of climate adaptation

Many freshwater ecosystems are under strong pressure. We rely on them for supply of drinking water, irrigation, biodiversity, food production, and for electricity production. The economic and intrinsic value of keeping the aquatic ecosystems in good status and preventing extinction of species is difficult to measure. The cost of an ecological collapse and loss of all ecosystem services, resulting from lack of adaptation is incalculable.

Policy aspects 

All policy makers at regional level have the responsibility to plan for a sustainable future in a changing climate. The method used in this study can hopefully be used by other counties or surveyors of the environment. This case study relates to the following local policies and decisions:

SWICCA climate change impact indicators have contributed to these policies and systems as:

  • some fish species have demands on water temperatures and/or ice cover during their reproduction cycle. The results from this case study will give information on these parameters today and in the future. This can be used in project regarding fish management.
  • Following EU WFD Jönköping County need to assess the status in the water bodies in the county. The impact indicators retrieved from this project will be used directly in the assessment of the lakes investigated. The results will also translate to generally assess lakes similar to the ones investigated.
  • This SWICCA project will improve the knowledge basis on how climate change impact some aspects on lake physical behavior. This information will be used in deciding measures to maintain and achieve good ecological status following the EU WFD.


Katarina Stensen

E-post: katarina.stensen‹at›
Telephone: +46 (0)11 495 80 00
Address: Folkborgsvägen 17, 601 76 NORRKÖPING

Måns Lindell
Vattenenheten, Jönköping County Administration, Sweden



Relevant EU Policy


Purveyor: Katarina Stensen

E-post: katarina.stensen‹at›
Address: Folkborgsvägen 17, 601 76 NORRKÖPING

Value added by Copernicus Climate Change Service: 



Client: Måns Lindell
Telephone: 0046 (0)10 223 6408
Address: Hamngatan 4
551 86 Jönköping, SWEDEN
Vattenenheten, Jönköping County Administration, Sweden


Salvelinus umbla, also known as lake char, taken by Klas Balkhed (County Administrative Board in Jönköping)


Salvelinus umbla, also known as lake char, taken by Klas Balkhed (County Administrative Board in Jönköping)


Jönköping county divided into 8 different zones. For each zone 22 parameters of local weather and hydrological data have been produced.


Map over Stengårdshultasjön with depths (left). Hypsography for Stengårdshultasjön (right).