Grimwith Reservoir is one of the Yorkshire Dales' hidden gems tucked away off the road between Grassington and Pateley Bridge.
The first reservoir at Grimwith was built between 1856 and 1864 by Bradford Corporation Waterworks. At the time industrial Bradford was desperate for increased water supplies and had already built reservoirs on nearby Barden Fell. This meant reduced water power for mill owners further down the River Wharfe, particularly in Otley. During the early 1960s Bradford Corporation again needed more water. They negotiated with the remaining mill owners for the rights to the water at Grimwith and drew up plans to expand the reservoir. The top level of the water was raised by 20 metres and the whole area increased to 1150ha making it the largest expanse of inland water in Yorkshire.
The reservoir provides a vital stop-off point for migrating waders, geese and ducks as well as year round populations of birds. Various places around the reservoir have been set aside as nature reserves, so it is worth taking some binoculars.
There is a wonderful 7km (4 mile) walk around the reservoir which is all on good surfaces. The final 'missing link' section of difficult to use path was completely remade in 2015 by the National Park Authority with funding from Yorkshire Water and the British Mountaineering Council's Access and Conservation Trust.
There is a free Yorkshire Water car park on site with toilets, including an accessible toilet with Radar key.