Enhancing student understanding and engagement with quantitative relationships: the development of a class database of specific stream power for Irish rivers calculated from streamflow data and Google Earth measurements

Students with limited confidence in their mathematical abilities often struggle with fundamental concepts that are needed to understand the form, behavior and management of river systems. A key concept is that of stream power, which determines the energy available for erosional and transportational work. Three main variables determine the stream power per unit area of the channel bed: flow discharge (bankfull); energy slope of the water surface (which can be approximated by channel bed slope); and channel width. Stream power at a given location can be calculated using on?line hydrometric data and simple measurements made in Google Earth. The exercise described here has been carried out by two third year fluvial geomorphology classes in NUIM (130 students) and a second year fluvial class in UCD (170). Each student selected a stream gauge location from the OPW Hydro?Data hydrometric dataset, and extracted a representative discharge. Channel slope for this location was calculated from measurements made in Google Earth. Channel width was also measured and a mean annual specific stream power, in watts per m2, calculated. Students entered these data to a class database supported by Moodle, which enabled the analysis of spatial variations in stream power and consideration of issues such as data sampling and measurement error. Feedback was very positive, with most students stating that the exercise had enabled them to really understand the equation, which to some had initially seemed confusing. Students also welcomed the opportunity to contribute to a piece of original research, since this is the first time such a database has been constructed for Irish rivers. This type of approach has potential for application in other areas of physical geography.