Tidal flow over shallow bathymetry is known to create an identifiable sea surface signature in satellite synthetic aperture radar. Here we present results investigating a similar effect visible on ground based marine radar data recorded at a tidal energy test site. Sea surface roughness signatures generated by strong flow over uneven bathymetry create patches of tidally modulated radar backscatter that may be identified and quantified in an uncalibrated form. Further, we investigate whether tidal stream turbines and their support structures might also create such tidally modulated sea surface signatures related to their turbulent wakes. Initial analyses have identified tidally modulated areas of roughness that are centred on the locations of turbine foundation structures. These however, are dwarfed by the naturally occurring tidally modulated sea surface roughness signatures associated with steep gradients in the bathymetry and shear zones around headlands.