Baltic Compass project installed an automatic nutrient load measuring system at Pitkäkoski in the river Vantaanjoki in October 2010. The installed monitoring system is part of the Baltic Compass project's identification of agricultural nutrient run-off risk areas. Sirkka Tattari, the leader of Work Package 5 coordinated the planning of installation with Luode Consulting; a company specialized in water measuring technology.

The measuring system consists of an optical water quality sensor and a water-pressure sensor coupled with wireless data transmission devices. Every hour the sensors will automatically take exact measurements of the turbidity and the nitrate concentration. From the turbidity data, the total phosphorus (TP) concentrations can be calculated according to the correlation between turbidity and TP analyzed from the water samples taken in the same place. Baltic Compass will thus get measurements for the calculations of nutrient loading in the river Vantaanjoki every hour, which is a great advantage over "traditional" monitoring with occasional water sampling that leaves long periods unmonitored. In Finland, normal nutrient concentrations for a river like Vantaanjoki range between 0,5-5 mg nitrogen and 200-500 µg phosphorus. Weather-driven hydrology and the land use in the catchment will make the biggest effect on the quality of the water. The very first measurement showed that the turbidity was 10 FTU, the total nitrogen concentration was 2 mg and the water temperature was 4.1 °C.

The water-quality sensor is a spectrometer by an Austrian company s::can Messtechnik GmbH. The sensor is placed together with water temperature and –level probes at a depth of 1 m in naturally flowing water. From the hourly recorded data sent to the webpage of Luode Consulting, nutrient loading can be calculated very precisely. Previous water quality results from the river Vantaanjoki have been based on Helsinki Region Environmental Services Authority measurements taken 22 times per year. With the new monitoring system Baltic Compass aims at verifying if the previous measurements have been exact enough for reliable estimates of the nutrient loading via the river Vantaanjoki into the Gulf of Finland

The nutrient load measuring devices installed at the river Vantaanjoki will be operating as long as the Baltic Compass project is running, thus at least until the end of 2012. Baltic Compass aims to install a similar monitoring system also in the river Narew in Poland. In this way the two rivers could be compared and the nutrient load from their catchments interpreted. The river Vantaanjoki is a 101 km long river in South-Finland which has a catchment area of 1685 km². In terms of the land use in its catchment, the river Vantaanjoki is a typical river in southern Finland, there are about 1300 farms and 40 000 hectares of agricultural land in the catchment.