Browsing by Author "Jaakkola, Sauli"

Assessing and avoiding environmental impact of agriculture and forestry has become more and more important during recent years. In Finland, half of the phosphorus load and nearly 40 % of the nitrogen load in the water system is caused by agriculture and forestry. Traditionally water quality monitoring has been carried out with manual water sampling and laboratory analyses. The problem with manual sampling is low amount of samples. Continuously working water quality sensors have been used for a relatively short time, which is why continuous water quality monitoring needs more research. The objective of the study is to clarify the feasibility of optical sensors in monitoring water quality and nutrient loading in an agricultural and forest management area. The study was carried out in three monitoring stations of the Savijoki catchment in Southwest Finland. Two of the stations were identically equipped and were located in forested subcatchments. A third station was located at the Savijoki catchment discharge point, making it possible to study how sensors work in different water qualities. According to the study, monitoring with continuously working sensors will result in more accurate nutrient loading estimates. With sensors used in the study it is also possible to draw conclusions about dynamics between run-off and nutrient concentrations in water. A prerequisite for successful monitoring is utilizing the appropriate sensors in the correct location. For example, low nitrate levels in water in forested areas have to be taken into consideration when choosing sensors. During the monitoring it is important to actively keep track of the quality of data and to check that sensors are working properly. Water quality sensors always need good calibration and control water samples from the entire concentration range. Sensors also have to be equipped with an automatic cleaning mechanism.