On-line Learning Activities concerning Hydrologic Droughts and Drying Rivers

Tuesday, 8 December 2020: 07:28
Joann Mossa, University of Florida, Department of Geography, Ft Walton Beach, FL, United States and Hilary K McMillan, San Diego State University, Department of Geography, San Diego, CA, United States
Hydrologic drought refers to a deficit of water in one or more components of the hydrosphere, resulting in abnormally low streamflow in rivers and streams and low levels in lakes, reservoirs, and groundwater. Although physical factors such as climate and weather variations are typically the primary causes of droughts, anthropogenic factors such as irrigation, land use, reservoir-building, and diversions or extractions of water can also cause or exacerbate hydrologic droughts. Through the NSF-sponsored Hydrolearn Project, we co-created a module with active learning focused on hydrologic droughts and drying rivers. In this module, we give background to droughts by defining the types of droughts and clarifying what is and is not a hydrologic drought through case studies. We review concepts such as magnitude, frequency, and duration of droughts and their interactions, and examine the role of anthropogenic factors in causing and exacerbating hydrologic droughts. Second, we examine a variety of drought indices used in different situations and apply real-world data to the calculation of drought metrics. Next, we use streamflow data to examine flow regime and hydrologic droughts through using traditional daily flow, comparative before-after impact flow, and dimensionless flow duration curves. Students then learn strategies to communicate information about hydrologic droughts and drying rivers by adapting the climate or warming stripes method of Ed Hawkins, which uses color alone to convey trends in global warming, to create "streamflow stripes". Subsequently, students create streamflow heat maps or streamflow square strips to show trends and seasonal water deficits using monthly averages of streamflow over several decades. Finally, to promote authentic learning, students communicate as a water manager to various stakeholders about a hydrologic drought situation in a narration with highlights from their metrics and graphics. Through these activities, students learn a variety of ways to present and communicate streamflow data using spreadsheets. A take-home message is that water is a finite resource and that rivers across the United States are drying because of climatic and anthropogenic factors. This module or any part of it is accessible to other instructors interested in active learning in their classrooms.