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Flow measurement in streams using video imagery
Author(s) -
Bradley A. Allen,
Kruger Anton,
Meselhe Ehab A.,
Muste Marian V. I.
Publication year - 2002
Publication title -
water resources research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.863
H-Index - 217
eISSN - 1944-7973
pISSN - 0043-1397
DOI - 10.1029/2002wr001317
Subject(s) - current meter , flow measurement , channel (broadcasting) , bathymetry , streams , flow (mathematics) , particle image velocimetry , flow velocity , current (fluid) , remote sensing , geology , open channel flow , velocimetry , root mean square , hydrology (agriculture) , environmental science , geography , meteorology , computer science , geotechnical engineering , engineering , optics , geometry , physics , turbulence , mechanics , mathematics , telecommunications , oceanography , electrical engineering , computer network
A video imagery technique for making flow measurements in streams and waterways is presented and used to estimate discharge for Clear Creek near Oxford, Iowa. A video camera was used to visualize the flow seeded with tracers. Measurements of free surface flow velocities were then made using particle image velocimetry (PIV) techniques. The velocity measurements were used as input to a hydraulic model, which uses kinematic principles (conservation of mass) to derive three‐dimensional flow fields for discharge estimation. A survey of five channel cross sections over a 7.15 m length of stream were made to define the channel bathymetry for the hydraulic model. The average channel width was 5.7 m, and the average depth was 0.2 m. The discharge estimate using the video technique (0.183 m 3 /s) compares well with the current meter discharge measurement (0.192 m 3 /s with an estimated standard error of 6.4%). The root‐mean square difference of the depth‐averaged velocity at the locations of the current meter measurements was 0.032 m/s. Potential applications of the video imagery technique include measurements of flood flows at ungaged sites, river monitoring from a remote site, and estimation of two‐ and three‐dimensional flow components.