Fresh water quality monitoring program is designed to collect long term water quality data from lakes and rivers. It serves EU obligated data collection among other interests. The data is used to detect variation in time in the measured variables and to assess the physiological and chemical state of the water body. The program is managed by the Finnish Environment Institute (SYKE). Regional centres for economic development, transport and the environment are responsible for the field work needed for maintaining the monitoring stations. Monitoring frequency varies between locations from annual to once in three, six or 12 years.