Welcome to find support for water protection!

Welcome to finding information, examples and practical tips for water protection!

Tools for water protection is a web-based toolbox providing support for implementing water protection actions at local level. It is designed for professionals and experts who do concrete work, strategic planning or make decisions on water protection in cities, municipalities, companies, NGOs or other organisations. The Toolbox provides information and tools that assist with water protection. In addition to practical tips, tools and background information, in the Bank of Actions you can browse actions that local organisations have already implemented for the protection of local waters and the Baltic Sea – and you can also share your organisation’s own actions! This site was established in 2015 by the EU Life+ funded project CITYWATER, in collaboration with the Baltic Sea Challenge. The first tools are based on the results of the CITYWATER project. The site is now managed and updated by the Baltic Sea Challenge. More tools and actions are needed – please contact us and tell us about your ideas! Read more on page About us!

The Baltic Sea Challenge

Action at the local level is the key! Join the network and find ideas, examples, best practices and possibilities for collaboration.

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Communication strategy

Find tips and guidelines on how to communicate the benefits of water protection efficiently to get your message through!

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Cost-benefit analysis

Learn how the benefits of water protection can be assessed and compared to the costs of implementation!

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Storm water solutions

Considering implementing sustainable storm water solutions? Read about solutions, tips and recommendations for practical work!

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Find inspiration and ideas in water protection actions implemented by the Baltic Sea Challenge network.
Browse the Bank of Actions!


Awareness raising

Hazardous materials

Littering etc.

Oil spill prevention

Research and monitoring

Shipping and boating

Stormwater management

Strategies and programs

Wastewater management


Drainage basin

Storm water wetland in Karisto

Actor: City of Lahti   ●   Year: 2015   ●   Address:

A constructed storm water wetland system collects, retains and purifies the storm waters from a residential area in Lahti, Finland.© Eila Palojärvi


During 2008–2011, a large storm water wetland was built in a new residential area in Karisto in the city of Lahti. In the wetland, storm water is retained and purified before entering the eutrophicated Lake Kymijärvi. Furthermore, by using a wetland storm water is handled in an open system which also provides recreational benefits the local people. The wetland of Karisto consists of a large sedimentation pond and a wetland area. A meandering creek collects storm water from a 138 ha large catchment area, mainly used residential living.


Based on the available data of storm water quality, the wetland was estimated to reduce annual nitrogen load from the catchment area to Lake Kymijärvi by 38 % (61 kg N/y) and phosphorus load by 33 % (2 kg P/y). Because the City of Lahti is located in the Baltic Sea catchment area, partly these nutrient amounts are reduced also from Baltic Sea nutrient load. The wetland system provides also recreational benefits for citizen. As the number of residents will increase in future, the number of people enjoying the benefits of the wetland will also increase, and thus the value of annual recreational benefit were estimated to grow from 10 000 €/y to 20 000 €/y.

Comparison of investment and maintenance costs with benefits relating to recreation and an improved state of the Baltic Sea on a 50 year lifespan, resulted in a net present value of ca 100 000 €. This value did not include avoided costs from conventional underground storm water solutions such as  drainage pipes and dwells. Furthermore, ecological benefits, such as the positive impact on local water systems relating to biodiversity and groundwater generation, were neither possible to include in the analysis. Thus, the storm water solutions seems to be worthwhile investments in a social perspective.

Background information

The impacts and the net present value of this action were assessed in the cost-benefit analysis study conducted in the EU Life+ funded project CITYWATER.

Download the study here!

More information on implementing sustainable storm water solutions here!

Further information

Name: Päivi Airas   ●  Email: paivi.airas ( at ) lahti.fi   ●  Web page: https://www.lahti.fi/