The paper addresses the identification of the mechanisms that dominate the flow around a series of obstacles placed at the sidewall of a channel, representing fluvial groynes. Accordingly, 2D velocity fields were measured through Particle Image Velocimetry in a horizontal plane spanning the area between groynes and an adjacent portion of the main channel. Four experimental cases were performed, addressing two groyne separations and two submergence conditions (emerged and submerged). For the submerged case, the ratio water depth to groyne height was 1.3. Groyne separations were characterized according to the corresponding width-to-length ratio of the groyne field (lambda = W/L = 1 and 2). A complete description of the experimental conditions, objectives and outcomes can be found in the article. The following data is included: Meanfields_[case].csv: spanwise and streamwise components of the velocity field, velocity magnitude and uv component of the Reynolds stress tensor averaged over time. Reynoldsstressesprofiles_[case].csv: uv component of the Reynolds stress tensor averaged over time at selected transverse profiles. PSD_[case].csv: power spectral densities computed from fluctuating velocity series extracted at selected locations. Autoccorrelation_[case].csv: normalized transverse autocorrelation functions computed from fluctuating velocity series extracted at selected locations. PODenergycontribution.csv: energy contribution from the first 20 POD modes computed for the case studies. PODtemporalcoefficients.csv: temporal coefficients obtained from the first two modes for the case studies. PODspectra_[case].csv: spectra of the temporal coefficients corresponding to modes 1 to 4 for the cases in study. PODspatialmodes_[case].csv: first two spatial modes computed for the case studies.