Autumn rains and trout spawning season emphasise importance of construction site water management
With the arrival of autumn rains, construction sites generate more water runoff than usual. In Espoo, many streams serve as spawning grounds for endangered trout, and untreated construction site water can jeopardise their reproduction. Fortunately, there are many ways to prevent environmental harm caused by construction site water.
Untreated construction site water often contains high levels of sediment or harmful substances, which can burden natural water bodies and their ecosystems. Therefore, every construction site must treat the water and sludge generated, before discharging them into stormwater sewers or water bodies. To prevent environmental damage, the quality of the water being discharged should match that of natural waters.
Many streams and rivers flowing through Espoo serve as spawning grounds for endangered trout. The trout’s spawning season peaks in October, and the species is protected in rivers and streams from the beginning of September to the end of November. As a species, trout are sensitive and can easily be disturbed by changes in water quality. Sediment entering water bodies can smother spawning grounds and threaten the survival of the trout population.
Concrete guidelines for construction site water management
Key management methods:
- Advance planning: Construction site water management should be considered during the planning phase to ensure sufficient space is allocated for treatment structures.
- Location of soil masses: Soil masses should be piled up far from sewer grates and ditches to prevent runoff from carrying soil material into water bodies.
- Preserving vegetation: Plants absorb construction site water, bind soil sediments, and slow down the flow of water, allowing its efficient absorption.
- Versatile treatment methods: If water cannot be absorbed on-site, it should be treated before being discharged. Various methods, such as settling and filtration, can be used. You should use methods that are suitable for the site in question.
- Regular monitoring: The quality of discharged water should be monitored at least visually for turbidity. The pH value can also be measured if necessary. Structures used for treatment should also be maintained and monitored.
By following these guidelines, construction sites can help improve the condition of water bodies and contribute to the achievement of national goals. For more information, check out the Helsinki Metropolitan Area’s Construction Site Water Guidelines and help us protect our waters!
Read more: Construction site waters in Espoo