While most refuge trials to date have been at stillwater sites, floating raft refuges of the type outlined in Case study 1 have been successfully installed in relatively narrow sections of the River Lee in North London. These were secured to the steep, sheet-piled banks where there was no natural vegetation. Netting suspended from the rafts provided a refuge for the fish and the roots of the aquatic plants grown on the top extended down into the water column to provide an additional fish spawning medium and protection for fry. These structures enhanced the general appearance of the area and did not interfere with navigation; there was no opposition from boaters. In theory, provided they are secured correctly, such structures could also be used where water levels vary (e.g. tidal waters).