Helston periodically experiences flooding, caused by high amounts of surface runoff from the increasingly urbanized catchment flowing into a small and modified channel. Beatrix Webb (Masters student at Camborne School of Mines) spent 2015 investigating whether the geophysical technique of electrical resistivity can be used as a low cost method to improve the accuracy of flood prediction.
The technique works on the principle that stored water within soil could alter a soils electrical signature and can be detected by electrical resistivity measuring devices such as an ohmmeter. Soil moisture and subsequent infiltration rates are predominantly influenced by precipitation, temperature and land use. Soil moisture is a highly influential component in catchment hydrology dynamics influencing river levels and subsequently in flood prediction.
Primary data collection was carried out over a period of 11 weeks, from June to August at four different sites within the Cober River catchment near Helston. Results show the methods potential to be able to detect changes in soil moisture conditions, as it was sensitive to changes in all variables, especially precipitation. The study concludes that the method may form the basis of improved flood forecasting.
For Beatrix Webb’s full MSc Dissertation click here The potential to use electrical resistivity to enhance flood prediction or see Research & Reports page.