|Paper title||Water quality monitoring and status assessment of Finnish lakes|
|Form of presentation||Poster|
The Finnish Environmental Administration has invested in and advanced the utilization of satellite observations to collect environmental data focusing on water quality. The Copernicus program, along with NASA Landsat-programme, provides long-term opportunities and perspective for this. Starting from 2017, Finnish Environment institute (SYKE) has been developing a publicly open TARKKA (https://syke.fi/TARKKA/en ) web map service through which users can utilize satellite observations. The TARKKA service focuses on providing water quality material and information for status assessment of Finnish water bodies. The need for the water quality monitoring via EO is heavily motivated by the extensive obligations of the EU directives (WFD*, but also MSFD**), the assessment of the state of the Baltic Sea (HELCOM*** holistic assessment, HOLAS), and the assessment of the impact of water protection measures. In Finland, the obligations set by EU for WFD reporting concern about 4500 lake and more than 250 coastal water bodies. As part of SYKE’s water quality EO development, a project named CorEO is working on diversifying and enhancing the water quality service based on satellite observations by introducing new analysis methods based on e.g., artificial intelligence. The improvements bring more user-orientation and visuality in TARKKA service.
In addition to the open TARKKA service, useful data on Finnish waters is also collected in a database available via STATUS interface, directed for the authorities responsible for directive reporting. The EO information database covers most of the water areas or bodies covered by the directives (especially the WFD). Although up to 70% of the satellite observations over Finland are partly cloudy, the database accumulates millions of observations from Finnish water areas every year. During the 3rd round of WFD reporting in 2019, Finnish authorities responsible for the lakes water bodies status assessment utilized EO as one source of information and found it to be beneficial to meet the requirements set by the directive. Approximately 40% of Finnish lake water bodies with WFD reporting obligations are included in the STATUS database. Finnish lakes represent wide range of optically complex waters – many of them are absorption dominated humic waters that form one extreme part of Case II waters. After the reporting, the database has been utilized to provide automated information on water quality and has been linked to various services providing information for citizens and authorities e.g. Marine Finland (https://www.marinefinland.fi/en-US/The_Baltic_Sea_now).
In the spring of 2020, automatic production of satellite observations was introduced, and proved to work fluently during the Covid-19 era; the processing, quality assurance and distribution of satellite observations went on schedule. As a side-result, the use of the TARKKA web service increased significantly during the spring and summer. Currently, the main challenge in data production is the vast and growing mass of observations as well as the development of related archiving and computing capacity to meet the future needs over the next ten years. For the following years, the development work will focus on improving the information content of existing services to become more user oriented. This includes development of methods that bring up the relevant part of the information related to water quality in various parts of the lakes in Finland from the vast amount of satellite observations. One of the first demonstrations for this was a service providing lake-specific information on cyanobacteria blooms over 43 Finnish lake districts in the summer 2021. For each of the lake district, the service provided also historical datasets as a background information, dating back to year 2013. From the user's point of view, it is useful to highlight the observations that illustrate the state of the areas requiring more attention or intensive monitoring. Recent development enhances the monitoring and surveillance of the state of the lakes based on satellite observations combined with other types of observation, like station water sampling and automated station observations.
In particular, the development focuses on the visuality and communicability of observations. One of the focus points is the development of automatic detection of sudden and long-term changes and identifying problem areas that require special attention (including nutrient sources, coastal estuaries, cyanobacteria). Anomaly tracking using artificial intelligence is another focus area for the development. In most cases, the spatial resolution of Sentinel-2-series MSI and Landsat-series OLI are sufficient to capture and identify the user needs like river water impact areas (turbidity and humus interlinked with nutrients), large and medium dredging areas, nuclear power plant condensate temperatures (TIRS-instrument), coastal, lake and offshore algae. The solutions enhance the introduction of data suitable for environmental monitoring in Finland.
*WDF: water Framework Directive, ** MSFD = Marine Strategy Framework Directive, ***HELCOM = Helsinki Commission, i.e. Baltic Marine Environment Protection Commission