Sankey Valley Park Update

Many of my constituents have contacted me about Sankey Valley Park and most recently, the condition of the canal. As a frequent visitor of Sankey Valley Park, I fully share residents’ concerns and believe that we must do all we can to ensure the park is maintained and enjoyable all year round.

I have continued to raise concerns with the Council and on 5th August, Warrington Borough Council issued a general response in relation concerns raised by the wider community, including the Save Sankey Valley Park Facebook Page.

You can view the Council’s statement here:

Further to the above, I have also been in touch with the Environment Services team and have some further details in relation to specific questions raised on behalf of residents.


Aquatic water plant control along the former St Helens canal section that runs through Sankey Valley Park presents a number of challenges not easily overcome as the decline in one type of weed provides opportunities for others to flourish.


The Authority working in partnership with the Environment Agency and the Dallam and District Community Angling Club has implemented a four point water management plan.


An inert, organic water dye was introduced in April 2019 between Bewsey Bridge and Sankey Way in an attempt to reduce light penetration to the canal bed and reduce the vigorous growth of submerged aquatic vegetation in particular hornwort. Unfortunately, this has been unsuccessful. Physical removal is extremely time consuming and beyond the resources of volunteers from the angling club.  Mechanical removal is very costly and either option will provide only temporary impact, the process is similar to mowing an underwater lawn but requires very expensive equipment.


The canal has become inundated with a number of species of water lily. This plant although beneficial to wildlife in small quantities has developed significantly over recent years – physical removal is difficult and unless completely removed does not provide a long-term solution as the plant will regenerate with increased vigour from any small root pieces not removed. The council will be spot treating a number of the plants this year with an approved herbicide under licence from the Environment Agency. This will reduce the coverage, creating a central channel of lily free water between Sankey way and Callands Pool. The treatment programme will be sustained over a number of years and success monitored.  Applications will be undertaken towards the end of the growing season when nutrients are being reabsorbed by the plant as it naturally dies back for the winter. This is the most effective time to apply the herbicide as it is absorbed into the root.


Surface weed coverage continues to present a challenge – weed coverage experienced earlier in the year was predominantly Azolla. This non-native fast-growing plant has been successfully managed by biological control involving the introduction of a specific species of weevils that only eat the Azolla plant. A further population of weevils has been introduced this year.  Azolla is now scarce along the canal.

Wetlands reserve from Hospital Bridge

Azolla before weevil release

Azolla Before

 Azolla almost absent 3 weeks after

Azolla 3 Weeks After

Unfortunately, the habitat niche occupied by Azolla has been colonised by a native plant, duck weed. As the name suggest this plant provides a food source for British wildlife including wildfowl but grows very quickly covering the entire surface of open water.  There is no effective management of this plant, physical removal and / or chemical treatment provide only temporary respite as the species can reproduce rapidly from any individual plants left behind or untreated.  As the plant is native to the UK and forms a single layer over the water it is less detrimental to fish stocks. Its presence may help reduce significant dissolved oxygen spikes and troughs during a 24-hour period as the coverage will reduce light penetration.


The dog death at Hatchmere (as reported by Cheshire Live) relates to a blue green algal bloom – fortunately this type of bloom is rare in the Sankey canal and is currently not present in Warrington.   Blue green algae is known to be hazardous to animals and people if swallowed generally the situation is managed by signage and closing waters to water sport activity.


The council has limited resources to deliver grounds maintenance throughout the town. Routine vegetation management is undertaken as commensurate with the resources available.  Sankey Valley Park has benefited from capital investment over recent years. Projects have included play area refurbishment and significant woodland thinning to improve sight lines and open up views through the park. This work has had a positive impact reducing antisocial behaviour and improving public safety.

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