Research Confirms the Role of Citizen Science Contributions to Drought Detection and Monitoring

Timely information on drought impacts is important for developing and evaluating drought indicators, documenting drought events, reducing future risks, and enhancing public awareness. To address needs for better understanding and monitoring of localized drought impacts, this study recruited volunteers from the Community Collaborative Rain, Hail and Snow (CoCoRaHS) network to report on how weather and recent precipitation affected their local environments and communities. The study found that the reporting of conditions across a wet-to-dry scale by the CoCoRaHS volunteers reflect meteorological conditions, and provide on-the-ground details that are being incorporated into existing drought monitoring processes. The study was led by researchers from the Carolinas Integrated Sciences and Assessments (CISA), a NOAA RISA team, and the State Climate Office of North Carolina, with funding from NIDIS and the NOAA RISA program.

The project started as a pilot in North Carolina and South Carolina in 2013 as part of the Coastal Carolinas Drought Early Warning System (DEWS) and expanded to the national CoCoRaHS network in 2016. Volunteers indicate the level of wet, normal, or dry conditions they observe using the “condition monitoring scale bar,” and they can also provide a written narrative. The submitted information is accessible through an interactive web map (Figure 1).

Drawing from the more than 7,000 reports submitted by 431 observers in the Carolinas from October 2016 to June 2020, as well as feedback provided by agencies responsible for drought monitoring, this study assessed the usefulness of the reports for drought monitoring and decision making. Three dimensions of usefulness were considered: the extent to which volunteers’ assessments of conditions correspond to quantitative indicators (namely EDDI, SPI, SPEI), how their qualitative narratives depicted changing conditions, and agencies’ actual use of the reports. 

The evaluation indicated that the volunteers’ scale bar selections align with commonly used quantitative indicators, with the 14-day Standardized Precipitation-Evapotranspiration Index (SPEI) showing the strongest correlation. While the content of the written narratives varied considerably, the most comprehensive reports included information that helped to capture the complexity of different drought stages and impacts, for example during drought onset when topsoil layers and plants show stress and deeper soil levels and water resources are not yet affected. Individuals involved in monitoring indicated that they found the volunteer reports and their assessments to be credible, relevant, and timely. The reports themselves provided on-the-ground verification of conditions and pointed to places that warrant further investigation by official drought monitoring committees (Table 1). Reports from volunteers who report regularly, that is every one to two weeks, were considered to be most useful.

The extent and nature of report use by decision makers in the study varied and depended on organizational activities and staff capacity to regularly assess the reports’ use and utility. These reports are not widely used beyond drought monitoring, in part because their design and volunteer training has focused on collecting drought-related information. However, the narrative reports often contain additional information, such as about recent weather events, that could inform the writing of weather event summaries or climate overviews. The highly localized information provided by observers can fill drought monitoring gaps by ground-truthing quantitative indicators and offering information in places where other monitoring tools may not exist. Overall, the research team found that strategic investments in time and funding can help fill in geographic and temporal gaps in drought monitoring information through volunteer observations. Consideration of the resources required to recruit and train new volunteers, for paid staff to engage with volunteers and to quality control and assure volunteer-collected data, as well as the investments made by volunteers themselves, helps to sustain high-quality data collection. 

The study team included Amanda Farris and Kirsten Lackstrom of the Carolinas Integrated Sciences and Assessments (CISA), a NOAA RISA team, and Rebecca Ward of the State Climate Office of North Carolina. Other partners included the Community Collaborative Rain, Hail and Snow (CoCoRaHS) network, the National Drought Mitigation Center, and North Carolina and South Carolina State Climate Offices.