Eel passes will be required wherever eels are present but are prevented from upstream migration; the Environment Agency will undertake an exercise to identify such locations during 2010.
The Environment Agency estimates that approximately 500 schemes (involving between 10-20 eel passes per scheme) will be required. Eel passes generally cost significantly less than those required to enable the migration of salmonids and can be in the order of between £500 to £2,000 per pass. However, where other substantial works are ongoing at the same time, the additional cost of building an eel pass or other easement can be much reduced. A separate assessment of the effect on small-scale hydroelectric schemes of the requirement to provide eel passes has not been made.