A Streams of Thought contribution by Paola Mazzoglio and Miriam Bertola.

The potential of  citizen science in hydrology

Citizen scientists (i.e., volunteers who help conducting tasks in scientific research) have the potential to play an important role in hydrology. The main advantage of Citizen science initiatives is that they engage a broad range of individuals since no previous knowledge of the research topic is needed, including ordinary people, students, and educators, and both sides benefit from this collaboration. On the one hand, these initiatives are opportunities to disseminate scientific knowledge and awareness to the public about water-related challenges. On the other hand, citizens contribute to collective tasks that speed up scientific research.

The role of citizen scientists is generally the collection and the analysis of data on water resources or on some component of the water cycle, mainly in terms of quantity and quality. This includes taking measurements of streamflow, rainfall, water temperature, pH, dissolved oxygen, and other parameters using simple, low-cost tools such as meters, test kits, computers and smartphones. Citizen scientists can, for example, collect water samples for laboratory analysis, which provide information on nutrient levels, sediment loads, and the presence of contaminants. In addition to collecting data, citizen scientists can assist in analyzing and interpreting it.

In recent years, several citizen science initiatives aiming at recovering data from old, printed documents have been launched. Although there have been notable advancements in Optical Character Recognition (OCR) software and machine learning/artificial intelligence techniques in recent years, manual transcription remains the most accurate method for digitization of these documents. In several cases in fact, records are printed on old paper sheets, and the ink may have been partially damaged, making it challenging for automated processes to interpret the data accurately. For instance, an “8” may be mistakenly interpreted as a “3” under these conditions. Furthermore, these records often have irregular structure and include several annotations and handwritten corrections made by different individuals, each with varying handwriting styles. These distinctive characteristics limit the effectiveness of standardized automated methods.

Citizen Science initiatives for the collection of in-situ data

The CrowdWater project (https://crowdwater.ch/en/start/) aims at investigating how ordinary people can be involved in the collection of in-situ hydrological data (such as water levels, qualitative data on soil moisture, data on the dynamics of temporary streams and plastic pollution), as well as what value the crowdsourced collected data can have for hydrological applications. The long-term goal of the project is to collect a large number of observations through the CrowdWater App and thus improve the prediction of hydrological events such as floods and droughts.

Water level data are collected also within the CITHYD project (http://www.cithyd.com/en/). In this case, users can scan a QR code placed in a set of gauged locations to report the water level they read on the gauge.

Another interesting project is based on the use of the Mini Secchi app and disk (https://pocket.science/products/mini-secchi), that is a small disk used to measure the transparency of water by lowering the disk into the water until it is no longer visible, and then measuring the depth at which the disk disappears. This measurement can be used by researchers to estimate the transparency of the water, thus providing an indication of its quality.

Citizen Science initiatives for the digitization of historical records

Rainfall Rescue (https://www.zooniverse.org/projects/edh/rainfall-rescue) is an example of how citizen science can help to unlock valuable data for scientific research. The project, led by Ed Hawkins, harnessed the power of crowdsourcing to accelerate the digitization of historical rainfall measurements recorded over the United Kingdom, available only in printed documents, made available as a scanned image on the Zooniverse platform.

More recently, the Weather rescue at sea project (https://www.zooniverse.org/projects/p-teleti/weather-rescue-at-sea) has been launched. The aim of this initiative is to extend the global surface temperature record back to the 1780s, based on the air temperature observations recorded across the planet. In this case, weather observations are digitized from historical ship logbooks, station records, weather journals and other sources.

In the Meteororum ad Extremum Terrae project, or Meteorology of the End of the World (https://www.zooniverse.org/projects/acre-ar/meteororum-ad-extremum-terrae), citizen scientists help recover the data of the Argentine historical weather records. Another recent initiative is the Alpine weather news project (https://www.zooniverse.org/projects/yuri-dot-brugnara/alpine-weather-news) aiming at digitizing meteorological measurements made in the city of Bolzano/Bozen (South Tyrol) between 1842 and 1873 and published on a local newspaper.

The SIREN project

In Italy there is a huge potential for citizen scientists in hydrology. The National Hydrological and Mareographic Service (SIMN) has been responsible for managing hydro-meteorological data collection at the national level since the early 1900s. However, around 30 years ago, the SIMN was dismantled, and the data collection task was transferred to the regional level, which consists of 19 Regions and 2 Autonomous Provinces. This shift has resulted in challenges in accessing complete and consistent records for the entire country.

While data collected in recent years is typically available in digital format, historical measurements are often only available in the printed version of the Hydrological Yearbooks published by the National Hydrological and Mareographic Service. A few initiatives have attempted to recover this information in the past, but their focus has been limited to a few years and/or specific regions.

Within the SIREN (Saving Italian hydRological mEasuremeNts) project, we aim to digitize the historical time series from historical Hydrological Yearbooks and to produce a consistent dataset. Phase 1 of the SIREN project will be devoted to recovering daily discharge measurements over the main Italian rivers (Figure 1).

This new dataset could allow us to better understand the climate of the last century in Italy and could be useful to estimate how river floods, drought periods and, more generally, the climate, might change in the future.

If you are interested in contributing to the digitization of this data, on https://www.zooniverse.org/projects/siren-project/siren-project you will find information about the project and a digitization tool! Even just 10 minutes of your time will be precious for the project!

Research group made of Paola Mazzoglio, Luca Lombardo, Alberto Viglione, Francesco Laio and Pierluigi Claps of the Politecnico di Torino and by Miriam Bertola of the Vienna University of Technology. Project released by Politecnico di Torino – Department of Environment, Land and Infrastructure Engineering during the World Water Day, 22 March 2023.