Barriers and Fish Passes   The Eden Rivers Trust, in several partnership projects, is making progress in opening up large areas of inaccessible river habitat to migrating salmonids by installing fish passes in barriers. There are many different types of fish pass that can be used to alleviate fish passage up impassible man made barriers. The type of pass suitable for each barrier varies depending on several factors including head height difference over the weir; flows; length of weir; slope; etc.  Ensuring that the pass is suitable for trout and small salmon to get up is a priority and Eden Rivers Trust is also looking into attaching elver passes down the side of the fish passes. A fish pass has been installed in the River Leith opening up 6km of spawning habitat. This is a Larinier baffled fish pass which is very effective at passing both coarse fish and salmonids. The baffles slow the water speed allowing the fish to pass up the channel and because the top of the channel is lower than the top of the weir, in low flows the channel takes priority flow and water passes down the fish pass. A natural rock pre–barrage downstream has been added to raise the water height to cover the toe of the weir allowing the salmonids easy entrance into the fish pass. The Trust, working with the Environment Agency, Natural England, Rural Regeneration Cumbria and Hanson Quarry has now installed fish passes in the River Leith, Lyvennet, Hoff and Augill. Electrofishing sites have been surveyed upstream of the weirs/barriers to allow monitoring of the success of the fish passes in future years.