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ARS Home » Midwest Area » Ames, Iowa » National Laboratory for Agriculture and The Environment » Agroecosystems Management Research » Research » Publications at this Location » Publication #408828
Research Project: Sustainable Intensification in Agricultural Watersheds through Optimized Management and Technology

Location: Agroecosystems Management Research

Title: Effects of submergence on flow characteristics upstream of boulders: Implications to sediment deposition and bed morphology

Author
item WYSSMANN,, M - University Of Missouri
item SCHWARTZ, J - University Of Tennessee
item CODER, J - Pennsylvania State University
item Papanicolaou, Athanasios

Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2023
Publication Date: 12/11/2023
Citation: Wyssmann,, M., Schwartz, J., Coder, J., Papanicolaou, A.N. 2023. Effects of submergence on flow characteristics upstream of boulders: Implications to sediment deposition and bed morphology [abstract]. Meeting Abstract. Vol. 76, p. 115-119.

Interpretive Summary:

Technical Abstract: In steep streams, large immobile boulders have substantial effects on flow, sediment transport, and bed morphological characteristics. Recent laboratory studies focused on the effects of boulders on sediment transport under different submergence conditions have highlighted a reversal of sediment depositional location between low and high submergence conditions. Namely, sediment preferentially deposited in the upstream region for low (or partial) submergence conditions and preferentially deposited downstream for high submergence conditions. Focusing on the upstream region, this study obtained measurements of turbulent flow fields in a laboratory flume in the upstream vicinity of model boulders to determine if differences in flow characteristics may lead to the observed differences in upstream sediment deposition. Turbulent flow field measurements were obtained using a volumetric particle image velocimetry (PIV) system and within a region extending about two diameters upstream of model boulders. Two experimental flow conditions were employed, which were denoted as the partially submerged (PS) and the fully submerged (FS) boulder conditions. Based on the PIV measurements, flow characteristics upstream of the boulder for the PS condition were shown to exhibit more rapid flow deceleration than the FS condition. The observed differences in flow deceleration are expected to promote preferential deposition upstream of boulders for partial submergence conditions. Effects of boulder submergence on upstream flow deceleration is thus one potential mechanism by which submergence may influence bed morphological characteristics in the vicinity of boulders.