Testing a novel sonar‐based approach for measuring water depth and monitoring sediment storage in beaver ponds

Widely available ‘fish-finder’ echo-sounding devices are beginning to be used in bathymetric studies estimate geomorphic change. To date, however, there have been no applications shallow and complex wetlands, where changes sediment storage notoriously dynamic time difficult describe accurately space. Therefore, this study, we tested the performance of an ‘off-the-shelf’ fish-finder for mapping bathymetry a beaver pond. We sonar depth readings against traditional-sounding lead-line method across 21 paired Sampling Points with minimum 0.31 m mean 0.65 m. Spatial accuracy unit was also differentially corrected Global Navigation Satellite System (GNSS) receiver. Measured depths pond bottom from were on average within 5%, although significantly 0.015 (SD = 0.034) less than those obtained by method. accuracy, varied greatly compared GNSS receiver readings, discrepancy 2.7 1.5) but up 6.2 Given close match between two methods, conclude that is suitable, cost-effective, less-intrusive existing techniques, even moderately vegetated waterbodies. Methods do need adopted account poor spatial precision models, can rectified survey design or using secondary GNSS. Application technology will allow rapid one-off surveys repeated monitoring depth, bedform accumulation otherwise hard-to-access disturbance-sensitive such as ponds water treatment flow attenuation wetlands.