Royal Mills Sluice and Channel

For Options Blue, Pink and Orange, we would remove the sluice gates at Viaduct. During normal river flows, water would tend to naturally flow through Viaduct. This means there will be no water flowing through Royal Mills sluice. As a result, the channel immediately upstream of the pedestrian footbridge will get more vegetation growing in it which we may need to manage accordingly. When river flows increase, typically during the winter months, water will once again flow over Royal Mills sluice.

The loss of the water cascade at Royal Mills would allow for more biodiversity improvements for 5.5 to 6km of river upstream and to encourage fish to pass through a new rock ramp proposed at Viaduct sluice. Enabling fish passage during refurbishment of river structures is a legal requirement.

Option Purple

We would only carry out reactive maintenance and repairs as the structures gradually fail, and also allow for fish passes to be added in the future. There would be similar levels of plant and animal habitat along and in the river. The water levels would remain similar to the current situation.  

Option Red

The existing gate will be removed and replaced with a fixed crest weir. This will not result in any changes to the water level upstream of the structure.

Option Blue

The existing gate would be removed and the channel upstream of the structure locally infilled to remove any low spots along the river bed. The removal of gates at Viaduct Sluice will result in the channel upstream of Royal Mills running dry under normal flow conditions.

Option Pink

The existing gate would be removed and the channel upstream of the structure locally infilled to remove any low spots along the riverbed. The removal of gates at Viaduct Sluice will result in the channel upstream of Royal Mills running dry under normal flow conditions.

Option Orange (national economically preferred option)

The existing gate would be removed and the channel upstream of the structure locally infilled to remove any low spots along the riverbed. The removal of gates at Viaduct Sluice will result in the channel upstream of Royal Mills running dry under normal flow conditions.


For Options Blue, Pink and Orange, we would remove the sluice gates at Viaduct. During normal river flows, water would tend to naturally flow through Viaduct. This means there will be no water flowing through Royal Mills sluice. As a result, the channel immediately upstream of the pedestrian footbridge will get more vegetation growing in it which we may need to manage accordingly. When river flows increase, typically during the winter months, water will once again flow over Royal Mills sluice.

The loss of the water cascade at Royal Mills would allow for more biodiversity improvements for 5.5 to 6km of river upstream and to encourage fish to pass through a new rock ramp proposed at Viaduct sluice. Enabling fish passage during refurbishment of river structures is a legal requirement.

Option Purple

We would only carry out reactive maintenance and repairs as the structures gradually fail, and also allow for fish passes to be added in the future. There would be similar levels of plant and animal habitat along and in the river. The water levels would remain similar to the current situation.  

Option Red

The existing gate will be removed and replaced with a fixed crest weir. This will not result in any changes to the water level upstream of the structure.

Option Blue

The existing gate would be removed and the channel upstream of the structure locally infilled to remove any low spots along the river bed. The removal of gates at Viaduct Sluice will result in the channel upstream of Royal Mills running dry under normal flow conditions.

Option Pink

The existing gate would be removed and the channel upstream of the structure locally infilled to remove any low spots along the riverbed. The removal of gates at Viaduct Sluice will result in the channel upstream of Royal Mills running dry under normal flow conditions.

Option Orange (national economically preferred option)

The existing gate would be removed and the channel upstream of the structure locally infilled to remove any low spots along the riverbed. The removal of gates at Viaduct Sluice will result in the channel upstream of Royal Mills running dry under normal flow conditions.


Page published: 15 Aug 2024, 09:29 AM