Implementing smart energy management concepts in WWTPs






In the map below, you can find examples of water protection measures within this topic. These actions are picked from the Bank of Actions - if you are interested to browse other water protection actions, visit 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

Buffer zones on riverby fields

Actor: City of Turku   ●   Year: 2015   ●   Address: Puolalankatu 5 Turku, Finland

The City of Turku owns agricultural land and leases it to local farmers with a special condition of establishing extra-wide buffer zones on the riverside fields. © Timo Sirkiä


The City of Turku is one of the largest agricultural landowners in Finland: it owns 2000 ha arable land and leases 1600 ha of it to local farmers. As a landowner, the city can influence water protection of the local agriculture. In 2005 the city included a special condition of establishing extra wide buffer zones in land lease contracts. The buffer zones are on average at least 15 metre wide vegetated zones, which are established between a field and a water course to reduce the surface runoff of nutrients and soil erosion.

Nowadays there are approximately three kilometres of buffer zones by the river Aurajoki and other rivers in the Turku area. The buffer zones are 100 m wide at the widest. In practice, the location and the width of buffer zones is dependend on size, inclination and location of the field, and usually decided by the city but sometimes together with the farmer. 


Two case fields were studied in the cost-benefit analysis conducted during the CITYWATER project. The larger field is located by the river Aurajoki and the smaller by the river Vähäjoki, which flows to the river Aurajoki. Annual nitrogen leaching was estimated to reduce by 70 % and phosphorus leaching by 50 % due to the buffer zone by the river Aurajoki, and respectively 75 % and 21 % due to the buffer zone by the river Vähäjoki. The differences in efficiency are due to differences in tilling practices, characters of the field and the width of the buffer zone. These two buffer zones, in total covering a 5.6 ha area, reduce annual nutrient leaching from the fields by 240 kg N/y and 40 kg P/y.

When the nutrient reductions to the Baltic Sea and the profitability impact for farmers were taken into account, the net benefits during the leasing periods was 41,000–507,000 € by the river Aurajoki and –4,000-20,000 € by the river Vähäjoki, depending on the scenario of the Baltic Sea protection in the future. The results are promising because the reductions are multiplied if buffer zones are applied widely in the area. In addition, buffer zones seem to be worthwhile both for the farmer and in a wider social perspective.

Background information

To get special agri-environmental subsidy rights from the EU, the buffer zone should be established in a place where the risk for nutrient leach and erosion as well as the impact on the local water system are high. In addition, a plan on how to establish and maintain the buffer zone is required for a 5 or 10-year period. The use of fertilisers and chemical protectants is further prohibited in the buffer zone.

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.

Further information of the study on buffer zones can be found here!

Further information on cost-benefit analysis can be found here!

Further information

Name: Timo Sirkiä   ●  Email: timo.sirkia (a)   ●  Web page:

Guidelines & Recommendations

Guidelines & Recommendations