River Mersey, Warrington, Flood Risk Management Scheme

Introduction

The 2009 National Flood Risk Assessment showed that Warrington had the tenth highest number of properties at significant risk of flooding in the country. Warrington is at fluvial and tidal flood risk from the river Mersey and its tributaries.

The Environment Agency’s £34 million flood risk management scheme, which was delivered between 2012 and 2017, has provided improved flood protection to approximately 2,400 local homes and businesses.

In addition, the scheme protects vital infrastructure, such as the Scottish Power High Voltage Grid Substation on Howley Lane, which serves approximately 2/5 of Warrington.

The completed scheme has helped to bring investment to the area. As a direct consequence of the flood alleviation scheme, the Howley Quay area has been re-developed with affordable housing; and the scheme has been a catalyst for further investment in recreational facilities and amenity improvements at Victoria Park.

The Environment Agency worked in partnership with Warrington Borough Council (WBC) and Scottish Power (SP) and other local stakeholders to deliver this scheme. Although the majority of the funding for the scheme was from Government Grant-in-Aid, substantial funding and “in-kind” work contributions were received from both WBC and SP and these were essential for the success of the scheme.

Overview

Knutsford Road flooding 1990

Victoria Park flooding 1990

Prior to the scheme being completed, the risk of flooding to some areas of Warrington from the River Mersey was estimated to be as high as a 1 in 20 chance in any year.

In February 1990, the River Mersey overtopped its banks flooding Knutsford Road and properties in Latchford East, Latchford, Howley, Arpley Bridge and Lower Walton. This event could have been much worse with flood water reaching within inches of 1,500 densely packed terraced houses.

The completed scheme has significantly reduced the risk of flooding from the River Mersey and its tributaries, with the risk now being a 1 in 100 chance in any year.

High tides in December 2013 tested the Phase 1 flood defence; and had they not been constructed up to 200 homes could have been flooded. The predicted value of damage to properties that would have otherwise occurred, covered the actual cost of this section of the scheme.

High tide in December 2013

The River Mersey Warrington Flood Risk Management Scheme comprises:

Comprising 5km of flood walls and 2.2km of embankment, the 7.2km scheme has improved amenity and recreational opportunities, as well as habitat conditions along the river corridor.

The widening and clearing of formerly impassable footpaths has improved connectivity, as well as views of the river and across the town, and extensive tree planting has created many pleasant vantage points for walkers and cyclists.

At the Twiggeries site behind Kingsway North, a 500m section of Padgate Brook has been realigned to create a more natural look and 5 hectares of reed bed habitat has been established to attract wildlife to the area.

The town’s main park, Victoria Park, has seen major improvement works to the main entrance, and a ‘wavy-topped’ railing along the road frontage at Knutsford Road makes a strong urban design statement.

The scheme was designed not only to be functional but to be aesthetically fitting within its environment. Children from local primary schools were challenged to create the winning artworks that adorn the defence walls, from Kingsway North all the way along Knutsford Road.

Wall cladding with texture and wave feature

School artwork

Due to the scale and complexity of works, the scheme was delivered in a number of phases:

Phase 1 completed in December 2013.
Phase 2 construction works in the Howley area of Warrington started January 2014 and Phase 2A work to Scottish Power Substation started in April 2014 both were completed December 2014.
Phase 3A completed June 2016.
Phase 3B started June 2016 and works are scheduled to be completed in August 2017.
Phase 3C started June 2017 and completed April 2018.
The scheme officially opened in January 2018

Plan showing phasing of the works

The work done by the Environment Agency will bring peace of mind to many Warrington people with improved standards of flood protection to homes and businesses along the Mersey.

It is more than just functional though, as you will see if you take a walk by the river. It is an attractive addition to the waterfront and has improved the ecology and helped protect wildlife in the area.

The Flood Hub