 The Lower Rivington reservoir has two dams - the Millstone Embankment, which is long and high, and the Horwich Embankment, which is long and high.Filter beds were constructed at the foot of the Horwich Embankment, The original sand filters were replaced by a new treatment plant from where a pipeline runs to the service reservoirs at Prescot.The River Douglas was diverted through a paved channel in deep cutting into Lower Rivington.