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. 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 can change for a few lakes in Jönköping County. Changes in air temperature, retrieved from the 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.
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
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.
The results from the case will be used:
- in decisions regarding measures for preserving fishes, especially cold water species, specifically those 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 the environmental monitoring program at the County and is saved in databases together with other local data. The environmental monitoring program is shared within the county as well as with municipalities within the County.
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.
- Increased knowledge in general about climate change.
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)
In this case study the contact persons at Jönköping County administration has been active and communication have been held continuously. Three project meetings have been held, two in person and the third one over lync (internet). In autumn 2017 a last meeting will be held to present and discuss results. 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 have been presented at the conference “Naturforum” in Jönköping. A lesson learnt at the conference was that many consider lakes as much more stable in temperature than observations and model results show.
Data will be shared in simple data format to make it accessible for everyone involved. Results will also be published in a report.
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 might be developed with local environmental data.
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.
The agile approach held in the SWICCA project gave good prerequisites for usable results. As an example, 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 these global indicators would be impossible to verify with local 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 method it was very easy and clear to download indicators. The SWICCA demonstrator both display 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 (RCP 2.6, RCP 4.5 and RCP 8.5) as in SWICCA. To communicate the different input data and possibly different results for the two projects will be very important.
Jönköping county have responsibility to include climate change in future planning, state supervision, permission and environmental monitoring. In this case study focus is on giving Jönköping county more information of the magnitude of impact of the physical properties in lake due to climate change. The results will help the client prioritize in questions regarding water temperature.
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 and will be used in project regarding fish management. The results from this case study will also give information on practical issues such as when to best monitor lakes. As an example autumn environmental monitoring of lakes is performed when the lake is the most stratified which have been assumed to happen in the end of august. With climate change this will occur later in the fall.
“With the new information on when the lake has the sharpest thermocline, we can perform better environmental monitoring in a warmer climate.” Måns Lindell at Jönköping County.
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.
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:
This SWICCA project will also improve the knowledge basis on how climate change impact some aspects on lake physical behavior. This information is crucial in deciding measures to maintain and achieve good ecological status following the EU WFD.
Telephone: +46 (0)11 495 80 00
Address: Folkborgsvägen 17, 601 76 NORRKÖPING
Vattenenheten, Jönköping County Administration, Sweden
Purveyor: Katarina Stensen
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