Stormwater refers to rainwater or meltwater from built-up areas that flows on the surface of the earth. As the urban structure becomes denser, impervious surfaces and the amount of stormwater increase, whereby traditional, efficient stormwater management systems, together with the effects of climate change, increase flooding, which causes harm to water bodies, nature and health. Harms caused by stormwater will increase if the current methods are not improved.

The goal of the City of Espoo’s stormwater programme is that the ecological condition of the stormwater catchments improves, and that the stormwater does not cause harm to health, safety, nature, comfort or the functionality of the city. Stormwater is also seen as a resource and an opportunity to create a more sustainable and better environment.

Espoo’s stormwater programme presents the principles, goals and most important measures for the comprehensive management of stormwater to achieve the goals. More detailed goals, vision, measures and division of responsibilities between the city’s different administrative authorities are presented in the programme’s appendices. Espoo’s stormwater programme was first drawn up in 2011 and was approved as a guideline by the council in 2012. Espoo’s stormwater programme from 2011 has been used as the framework for this update of Espoo’s stormwater programme.

The most important actions to achieve the goals of the stormwater programme are the improvement and development of cooperation and operating methods related to stormwater, increasing stormwater expertise and awareness, and even better stormwater information management. The aim of the stormwater programme is to bind actors who affect stormwater to adhere to common principles. The most important stormwater management measures that can best reduce the amount and quality of stormwater are preventive or carried out at the source. Stormwater management should be considered from a catchment area perspective, and management measures should be extended as necessary from the source to the drainage system. Stormwater should be taken into account in all aspects of planning.

In order to achieve the goals presented in the stormwater programme and to comply with the common principles, the commitment of the city’s trust staff and civil service management to the storm water program is required. A functioning stormwater system requires both targeted resources and allocated funds. The implementation of the stormwater programme is monitored and directed by the stormwater working group.

The main responsibility for stormwater management in public areas lies with the City of Espoo and in private areas with the landowner. In the distribution of responsibility and costs, the principle of causation should be followed, according to which all those who benefit from stormwater systems and those who cause the need for management participate in the investment, operation and maintenance costs of the systems.

In addition to flood control, good stormwater management improves the state of urban nature and small waters and increases the comfort of the environment. The development of stormwater management does not always bring large costs, but by sharing positive information and influencing attitudes, a lot can be achieved.