A new approach to the application of electrical resistance sensors to measuring the onset of ephemeral streamflow in wetland environments

Abstract

Ephemeral streamflow events in headwater catchments are significant in terms of the flux of sediments, solutes, and discharge out of a catchment. Existing attempts to monitor these events, however, have traditionally been restricted to a limited series of manual observations or the use of temperature sensors which demand a great deal of data interpretation and often introduce significant timing errors. The use of electrical resistance sensors has been found to be one potential alternative, but this method has not yet been fully explored. This paper builds upon this method, presenting a new low‐cost ephemeral streamflow (ES) sensor which is able to detect the onset and cessation of ephemeral streamflow events at high spatial and temporal resolutions. Furthermore, the data collected by the ES sensor needs only minimal interpretation. Laboratory testing reveals that the sensors are able to clearly distinguish between the presence and absence of water. Field testing in a small peatland headwater catchment in the South Pennines, United Kingdom, confirmed that the sensors were robust enough to withstand field conditions. Careful site selection enabled the production of a high‐quality data set, showing the timings of multiple ephemeral streamflow events at numerous locations within the catchment. The low cost, good performance, and minimal data interpretation requirements of the ES sensors permit unprecedented high‐resolution monitoring of ephemeral streamflows.