viivästysaltaat

Viivästysaltaat, also known as retention ponds or detention basins, are artificial structures designed to manage stormwater runoff. They are typically constructed in developed areas where natural infiltration is limited due to impervious surfaces like roads and buildings. The primary purpose of viivästysaltaat is to temporarily store excess stormwater and release it slowly over time, thereby reducing the peak flow rate into downstream drainage systems and natural waterways. This controlled release helps to prevent flooding, erosion, and pollution.

These basins work by collecting runoff from surrounding areas. During a rain event, water accumulates in the basin. The design of a viivästysallas often includes an outlet structure that regulates the rate at which the stored water is discharged. This outflow is typically much slower than the inflow, allowing the water to be released gradually. In some cases, viivästysaltaat are designed to hold water permanently, functioning as ponds, while others are typically dry and only fill during rainfall events.

Beyond flood control, viivästysaltaat can also provide water quality benefits. As stormwater is temporarily held, sediments and pollutants, such as oil, grease, and debris, have time to settle out of the water. Some designs incorporate specific features like vegetation and forebays to enhance pollutant removal through settling and biological processes. This can lead to cleaner water entering rivers, lakes, and other receiving bodies. The presence of vegetation can also create habitat for wildlife and contribute to the aesthetic appeal of a landscape.