EXPLAINER: What's happening with Athlone's flood defence plans?

 

Where did the Athlone flood defence plan emerge?

The initial decision to proceed with a standalone flood defence plan for Athlone was announced in October, 2016, by then Minister for the Office of Public Works and Flood Relief Sean Canney at a press conference in Athlone, flanked by his then fellow Independent Alliance TD Kevin ‘Boxer’ Moran.

The move meant the Athlone flood defence plan was being taken out of a lengthy and ongoing Shannon Catchment Flood Risk Assessment and Management process (CFRAM) process and proceeded with separately.

The need to prioritise flood defences in Athlone was identified after two catastrophic flood incidents, in November 2009 and December 2015/January 2016.

After the level of the floods of 2015/2016 (see above), it was decided to intitiate an Athlone flood defence plan.

 

What does the plan entail?

Initially, the works to be included in the flood defence plan involved the development of some ten walls, spanning somewhere between 1,038 metres and 1,358 metres, eight embankments stretching roughly over 1,600 metres, six floodgates totalling 16 metres and the raising of four roads.

However as it has evolved, some of the details have changed.

Funding of €6m was allocated. However, the scheme has since expanded in scope and is now expected to cost in excess of €12m.

The plan includes eight separate flood defence cells: The Strand/Wolfe Tone Terrace; The Quays; Brick Island/Jolly Mariner/Priory Park; Marine View; Iona Park/Iona Villas; Deerpark/The Park/Canal Walk; Creggan/River Al and Golden Island.

The breaking of the project into cells meant that the lengthy process of securing environmental reports and technical surveys on some of the larger cells did not delay work on other cells that could get underway immediately.

The work is being carried out by staff of the Office of Public Works (OPW), who, due to the splitting of the project into cells, were able to move from cell to cell as each section was ready to start.

A design for each cell is prepared by the OPW, including any required environmental assessments or more substantial Environmental Impact Statements.

In the case of the Deerpark cell, for example, this entailed the preparation of a 258-page technical report.

As the work is carried out by the OPW in conjunction with Westmeath County Council, the council must publicise the proposed plans, seek the views of the public through a consultation process and then prepare a report with recommendations for local councillors to approve.

 

What progress has been made?

Work started on the first phase of the project in November 2017, at Iona Villas.

From then, in successive phases, work started at The Quay, Brick Island, Priory Park and Wolfe Tone Terrace areas.

Currently, work has effectively been completed on the Iona Villas, The Quay, Brick Island/Jolly Mariner/Priory Park and Wolfe Tone Terrace defences.

Work at Priory Park and The Quays

It is planned to have floodgates inserted into gaps in the flood walls at The Quays and Wolfe Tone Terrace. These have been ordered but not installed.

The finished walls have yet to be cladded.

Work got underway last year at Marine View and also, on the largest single cell, the area in Deerpark/The Park/Canal Walk in August, 2019.
This covers a major stretch of land between the lock gates on the Docks and the Shamrock Lodge Hotel and it's planned to erect a massive 900 metres of flood prevention embankments and 750m of reinforced concrete flood defence walls/barriers and the installation of flood gates.

This cell costs €3m and is designed to protect up to 120 homes and businesses on the west side of the town including in Deerpark, The Park, Deerpark Road, Parnell Square, Canal Walk, Millbank and adjoining areas.

The old showgrounds in Athlone, where a major flood defence is currently being constructed.

A large amount of sheet piling has been completed in the former Showgrounds and near the Canal Walk housing estate in Athlone in the same area.

Sheet piling involves the driving of narrow, interlocking sheets six or seven metres into the ground to form a wall, or in this case, flood barrier, on top of which an overground flood embankment is subsequently constructed.

The sheet piling is visible in this picture at Canal Walk in December last.

It's likely the Athlone to Galway cycleway will be placed on top of the earthen embankments in this area, meaning they will need to be at least four metres wide.

It will be the end of 2021 or early 2022 before work on the Deerpark flood defences is fully completed.

The OPW says the construction of a new bridge over the existing Mick McQuaid canal bridge at the junction of Deerpark Road and Clonown Road is a major factor in this timescale.

Work has yet to get underway on the River Al/Creggan cell where a major environmental impact study was completed recently. Plans for this section of the flood defences were published in December, with the public consultation phase recently concluded.

It's expected a report on the matter will be before Westmeath County Council for planning approval in weeks.

Planning approval has also been granted for work in the Golden Island area, which will involve the construction of some 225 metres of flood defence walls, 120 metres of embankments and road-raising at the rear of Golden lsland Shopping Centre, stretching to Aldi.

Works also include culverting and diversion of short sections of existing drainage channels

Both the River Al and Golden Island sections of the flood defences are now expected to be constructed together.

 

Why are some areas preparing makeshift defences?

 

During the 2009 and 2015/2016 floods, residents created flood defences involving dams, built generally with sandbags, and assisted with water pumps.

The pumps simply direct floodwaters that breach the defences back away from properties.

They are also used to remove water from the vicinity of threatened houses or lands.

Pumps effectively buy time, keeping properties dry until the water levels drop.

In 2015/2016, the residents' efforts were then backed by Westmeath County Council and the OPW which provided a range of industrial-sized pumps that helped to keep urban areas dry.

In areas where the planned flood defences are either not completed or not commenced, similar makeshift defence have been created this time.

 

Why are there reports of sewage emerging during floods?

Large parts of Athlone's existing sewage collection network is based on a combined sewage system – which means the sewers also collects surface water runoff.

It means that in heavy rainfall, water enters the sewers then forcing raw sewage raw sewage to emerge through manholes into gardens and streets.

And aside from the heavy rainfall, floodwater from the Shannon also finds its way into the sewerage network.

Aside from the impact on property owners, these combined sewers can also cause serious water pollution problems during overflow events when the volume of the contents of the sewers exceed the sewage treatment plant capacity.

In order to protect the wastewater treatment plant from being flooded, the contents of the combined sewers, a mixture of storm water and sewage, are released into the Shannon and the Athlone Canal during heavy downpours.

Raw sewage continues to be pumped into the River Shannon and the canal at 19 locations in the Athlone area during heavy rain, storms or flooding events.
The issue was part of a successful prosecution by the European Commission against Ireland this year when the Court of Justice of the European Union in March last found that Athlone's wastewater treatment system, and those of a number of other Irish towns, was in breach of the requirements of European Directives.
 

Why are there pumps inside some of the constructed flood defences?

Surface water can gather inside flood defence walls, due to a combination of the heavy rainfall, the installation of non-return valves to prevent the contents of overcapacity-sewers flowing backwards and the flooding of local gullies.

This is fundamentally different to an incident of the river breaching the flood barriers.

The pumps simply control the level of surface water.

It's planned that some of the urban defences such as The Strand and The Way may include underground pumps that can be utilised in such circumstances.

A pump located behind the existing flood defence wall at Wolfe Tone Terrace.

What about more holistic flood solutions?

This is a flood defence scheme, not a flood prevention scheme.

Clearly, other proposals such as river dredging, improved river maintenance, rewetting of bogs, the introduction of water reservoirs, improved planting, more stringent regulations regarding building on flood plains, the increasing use of green areas and many other all have major parts to play in a wider solution to the increasing incidence of flooding.