Discharge estimation in small irregular river using LSPIV

This paper reports on an estimation method used to quantify discharge in the small irregular channel of the River Blackwater, using large-scale particle image velocimetry (LSPIV). The test reach (250 m × 60 m) consists of relatively straight and multiple meander channels, with a bankfull depth of 0·90 m and a base width of 4·25 m. Water surface velocities were measured by LSPIV at three sections along the river. Acoustic Doppler velocimeter (ADV) was also used on two occasions to measure velocity profiles for the validation of water surface velocities of LSPIV. In addition to this field work, velocity data derived from a 1:5 physical model of the river were available to compare with the field data. A comparison between the LSPIV data and ADV data was made and agreement was confirmed. The discharge correction factor method was suggested to estimate the discharge in the river. Discharge correction factors of 0·90–1·05 and 1·10–1·15 were proposed for inbank and overbank flow conditions respectively.