- Name of measurement site: Ruskeenkärki
- Location: Hattula, Vanajanselkä (south)
- Catchment area: Lepaa river (2420 km2)
- Coordinates ETRS-TM35FIN): P:6780666, I: 352630
The catchment area consists of Lepaanvirta and its upstream areas (2420 km2), and the catchment area around Lake Vanajaselkä (354 km2). The measurement site is situated in Ruskeenkärki at 79 m a.s.l., close to Lepaanvirta inflow. On-line measurements regarding optical phytoplankton detection by fluorescence and dissolved oxygen were started in spring 2009 and the rest of the measurements in spring 2015. Since the beginning also reference samples have been collected. The measurements have been running only during the open-water period. In the middle of Lake Vanajanselkä intensive measurement campaigns plus on-line measurements were carried out between 2009-2013. Water authorities and municipalities have been running their own monitoring programs in lake Vanajanselkä and also in many other water bodies for many decades. The very first water quality measurements were carried out already more than 100 years ago.