Evaluation of a runoff monitoring methodology for rangelands: UBeTubes

Authors: SCHALLNER, J.W. - New Mexico State University; JOHNSON, J.C. - University Of Arizona; Williams, Christopher - Jason; GANGULI, A.C. - New Mexico State University

Submitted to: Rangeland Ecology and Management
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/19/2021
Publication Date: 6/26/2021
Publication URL: https://handle.nal.usda.gov/10113/7430279
Citation: Schallner, J., Johnson, J., Williams, C.J., Ganguli, A. 2021. Evaluation of a runoff monitoring methodology for rangelands: UBeTubes. Rangeland Ecology and Management. 78:46-50. https://doi.org/10.1016/j.rama.2021.05.003.
DOI: https://doi.org/10.1016/j.rama.2021.05.003

Interpretive Summary: Land managers around the World require tools to quantify runoff on rangelands for assessing conservation practices and guiding management. Numerous approaches to measure runoff are available, each with advantages and disadvantages in resource requirements, degree of site disturbance, and quality and type of measure. This study assessed a relatively new method for monitoring runoff, the Upwelling Bernoulli Tube (UBeTube). UBeTubes are a low-cost, passive runoff monitoring method that estimates runoff from the height of water flowing out of a machined tube. We found that properly-calibrated UBeTubes could be a relatively accurate runoff monitoring method on rangelands. UBeTubes provide an alternative method to monitor runoff that can deliver near real-time measurements for natural precipitation events. Easily and rapidly deployed across the landscape, UBeTubes could allow for the relative measurement of hillslope hydrologic function and thereby serve as another source for developing sustainable rangeland management strategies on public and private lands.

Technical Abstract: Rangeland degradation is a global concern exacerbated by soil loss through water erosion. A deeper understanding of rainfall and runoff dynamics can assist in the development of sustainable management strategies. Current methods to measure surface runoff (e.g. natural runoff plots, rainfall simulation and overland flow experiments, modeling approaches) have many advantages but can be prohibitively expensive, may require considerable maintenance, and/or result in significant disturbance during installation. To address these limitations, we assessed a relatively new and under-utilized method for monitoring runoff, the Upwelling Bernoulli Tube (UBeTube). UBeTubes are a low-cost, passive runoff monitoring method that estimates runoff from the height of water flowing out of a slot machined in the side of a vertical tube. In this study, we evaluated the UBeTube across a range of flow rates with three specific objectives: 1) calibrate the UBeTube measurements using clean water, 2) assess the impacts from varying sediment loads on UBeTube measurement accuracy, and 3) evaluate accuracy under conditions similar to those on undisturbed and disturbed rangelands. We found that properly-calibrated UBeTubes could be a relatively accurate runoff monitoring method on rangelands (mean percent error = 7.7% - 35.7%). UBeTubes provide an alternative method to monitor runoff on rangelands that can augment current methods by providing near real-time measurements of runoff generated during natural precipitation events. Easily and rapidly deployed across the landscape, UBeTubes could allow for the relative measurement of spatially variable hydrologic dynamics and serve as another source of information for management decision-making processes and the creation of sustainable strategies for rangeland development.