Automated high frequency monitoring of Lake Maggiore through <em>in situ</em> sensors: system design, field test and data quality control

Abstract

A high frequency monitoring (HFM) system for the deep subalpine lakes Maggiore, Lugano and Como is under development within the EU INTERREG project SIMILE. The HFM system is designed to i) describe often neglected but potentially relevant processes occurring on short time scale; ii) become a cost-effective source of environmental data; and iii) strengthen the coordinated management of water resources in the subalpine lake district. In this project framework, a first HFM station (LM1) consisting of a monitoring buoy was placed in Lake Maggiore. LM1 represents a pilot experience within the project, aimed at providing the practical know-how needed for the development of the whole HFM system. To increase replicability and transferability, LM1 was developed in-house, and conceived as a low-cost modular system. LM1 is presently equipped with solar panels, a weather station, and sensors for water temperature, pH, dissolved oxygen, conductivity, and chlorophyll-a. In this study, we describe the main features of LM1 (hardware and software) and the adopted Quality Assurance/Quality Control (QA/QC) procedures. To this end, we provide examples from a test period, i.e., the first 9-months of functioning of LM1. A description of the software selected as data management software for the HFM system (IstSOS) is also provided. Data gathered during the study period provided clear evidence that coupling HFM and discrete sampling for QA/QC controls is necessary to produce accurate data and to detect and correct errors, mainly because of sensor fouling and calibration drift. These results also provide essential information to develop further the HFM system and shared protocols adapted to the local environmental (i.e., large subalpine lakes) and technical (expertise availability) context. Next challenge is making HFM not only a source of previously unaffordable information, but also a cost-effective tool for environmental monitoring.

Citizen Science Impact on Environmental Monitoring towards SDGs Indicators: The CASE of SIMILE Project

“…All the sources that were used were generally reliable but presented some errors and outliers of different nature in the raw data that were removed before comparing them. The CS data acquisition procedure has been explained in previous sections, SIMILE RS and HFM data acquisition procedure are explained in [37] and in [38], respectively.…”

Lake Water Quality Monitoring Tools

“…Several in-situ sensors were placed on the LM1 (Figure 1). The details of the sensors installed are provided in Tiberti et al (2021). They include sensors for water temperature, pH/redox, dissolved oxygen, conductivity, turbidity, algal pigments (chlorophyll-a, phycocyanin and phycoerythrin).…”

Automatic Assessment of Lake Status Using an Open Source Approach: Lake Lugano’s Case Study

“…In addition, the definitions of common data quality flags/codes improved the use of the software to indicate the quality of the observations inserted. In fact, when quality tests are performed on the data, the software allows to associate the observations to a flag that indicates which tests have been performed (Tiberti et al, 2021). In order to facilitate the import of historical data, a tool was implemented to extend the capabilities of istSOS (Figure 4).…”