UBeTubes: a new runoff monitoring methodology for rangelands

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

Submitted to: Society for Range Management
Publication Type: Abstract Only
Publication Acceptance Date: 12/12/2019
Publication Date: 2/19/2020
Citation: Schallner, J., Johnson, J., Williams, C.J., Ganguli, A. 2020. UBeTubes: a new runoff monitoring methodology for rangelands. Presented at the 73rd Annual SRM Meeting, Transformation and Translation, Society for Range Management, February, 16-20, 2020, Denver, CO, Poster Number 89.

Interpretive Summary: Runoff and erosion rates are key indicators of rangeland health. Highly variable vegetation and soil patterns on rangelands drive complex hillslope hydrologic processes. Currently, rainfall simulations are used to quantify hillslope runoff and erosion models, which help land managers predict runoff and erosion potential. Rainfall simulations allow for the controlled application of precipitation and measurement of the related runoff across variable landscapes, but are typically time and resource intensive. Furthermore, although rainfall simulation data is readily available, measurements of runoff from actual weather events is quite limited. To address the high cost of rainfall simulations and the lack of measurements from real events, a low-cost, passive runoff monitoring methodology originally developed for other purposes (i.e. road construction) was evaluated for use on rangelands. The methodology utilizing “Upwelling Bernoulli Tubes” (UBeTubes) was assessed in a controlled setting to determine its adequacy. Our testing coupled traditional flow measurements with those provided by the UBeTubes to evaluate efficacy under a variety of conditions expected during rangeland runoff events. Testing occurred over three phases beginning with clean water trials, followed by water preloaded with sediment, and concluding with overland flow across a simulated hillslope. The resulting measurements from both traditional methods and the UBeTubes were compared to assess accuracy and precision. The results of the comparisons suggest that this methodology could be used effectively on rangelands with some slight modification to the UBeTube design. We plan to expand the UBeTube testing through a small field deployment followed by an expanded deployment across multiple ecosystems. Overall, the data collected from this passive runoff monitoring methodology can be used to inform continuing modeling efforts and also provide a low-cost way to evaluate land management decisions in the context of runoff and erosion processes.

Technical Abstract: Runoff and erosion rates are key indicators of rangeland health. Highly variable vegetation and soil patterns on rangelands drive complex hillslope hydrologic processes. Currently, rainfall simulations are used to quantify hillslope runoff and erosion models, which help land managers predict runoff and erosion potential. Rainfall simulations allow for the controlled application of precipitation and measurement of the related runoff across variable landscapes, but are typically time and resource intensive. Furthermore, although rainfall simulation data is readily available, measurements of runoff from actual weather events is quite limited. To address the high cost of rainfall simulations and the lack of measurements from real events, a low-cost, passive runoff monitoring methodology originally developed for other purposes (i.e. road construction) was evaluated for use on rangelands. The methodology utilizing “Upwelling Bernoulli Tubes” (UBeTubes) was assessed in a controlled setting to determine its adequacy. Our testing coupled traditional flow measurements with those provided by the UBeTubes to evaluate efficacy under a variety of conditions expected during rangeland runoff events. Testing occurred over three phases beginning with clean water trials, followed by water preloaded with sediment, and concluding with overland flow across a simulated hillslope. The resulting measurements from both traditional methods and the UBeTubes were compared to assess accuracy and precision. The results of the comparisons suggest that this methodology could be used effectively on rangelands with some slight modification to the UBeTube design. We plan to expand the UBeTube testing through a small field deployment followed by an expanded deployment across multiple ecosystems. Overall, the data collected from this passive runoff monitoring methodology can be used to inform continuing modeling efforts and also provide a low-cost way to evaluate land management decisions in the context of runoff and erosion processes.