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Status and water quality of rivers and lakes

The natural values and recreational uses of water bodies such as rivers and lakes are particularly affected by the state of the water body. Most lakes in the Lahti region are included in the quality rating system of the EU Water Framework Directive.

In the Lahti region, the ecological status of surface water bodies is often worsened by excessive nutrient content. Ecological classification takes into account biological elements (phytoplankton, aquatic flora, benthic invertebrate fauna and fish fauna) as well as other critical water quality properties, such as nutrient content.

Ecological status of surface waters

The ecological status category shows how much human activity has changed the state of the water body from its natural state. There are five categories: high, good, moderate, poor and bad. The goal is to ensure that the ecological status of lakes is good.

Water quality monitoring

During the open water season, water quality in lake Vesijärvi is monitored by automatic monitoring stations installed on rafts as part of the lake’s conservation. The results of the automated monitoring stations can be tracked using the links on the side of the page.
The City’s Environmental Services also monitors the lake’s water quality with samples. Typically, water samples are collected twice a year. The national algae monitoring programme also has observation sites in Lahti during the summer. Water quality test results for lakes can be found on the environmental reports page, for example.

Pollutant load

The City of Lahti Environmental Services monitor the water quality of inflows to lake Vesijärvi with automatic monitoring stations. Pollutant load to lakes is also monitored with samples taken from brooks and other streams that flow into lakes. These test results are available on the environmental reports page.

Water management

The City’s Water and Environmental Management Unit is actively involved in the management of lake Vesijärvi and other public water body restoration projects and management measures around Lahti.

The aim of water body restoration and management is to ensure the good ecological status and recreational use of lakes and rivers. Restoration methods include, for example, restoration of rivers and streams, wetland restoration projects aimed at reducing pollutant load, and maintenance of meadows and fisheries. Environmental Services can provide a wide range of assistance in water management projects and even offer financial aid to local organisations for water body restoration projects.

Research and monitoring are also an integral part of water management and restoration. The Water and Environmental Management Unit works closely with the Lake Vesijärvi Foundation, universities and research institutes and other authorities in monitoring and research activities.