On Bannisdale, Bateman proposed a lower and an upper reservoir, as to create a single reservoir would have required a dam with a height of , which was too ambitious for the time. The lower reservoir required a dam with a height of to impound , with the dam located below Dryhowe Bridge. The upper dam was to be located half way up the valley, would have been slightly lower at , but would have had more capacity, holding of water. The fifth reservoir authorised was in Longsleddale, with a high dam located just above Sadgill farm. With a capacity of , it would have flooded most of the upper valley, with a water level at around above ordnance datum.