The Channel at Caherawooneen

caherawooneen.jpgThe area of Caherawooneen, Loughcurra and Dungory East play a pivotal role in the flooding dynamics of South Galway.  In the severe winter flooding of 2015, these communities provided the final overland connection of flooded South Galway Turloughs to the sea and were instrumental in helping to alleviate the distraught Cahermore community from even more hardship.  People talk about needing a channel to the sea for South Galway and currently Caherawooneen provides this connectivity.  It does this at a cost though as it can no longer take the amount of water and frequency of flooding and this has negative impacts for the local community.    A properly designed and sized channel that can safely transport water through this area would be of great benefit to South Galway communities, including a benefit to these communities as well.

Location

Caherawooneen is an located close to Kinvara on the north of the Cahermore road about 3km from Kinvara.  At its North-West side it is bounded by Loughcurra and connects via Dungory East to the sea north of Dunguaire castle.

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The map here shows the area in more detail.   There are two roads, Caherawooneen South and Caherawooneen North that link between Cahermore road and the Ardrahan road.

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Caherawooneen has no permanently flowing water but has two marshy areas known locally as the ‘Moneens’ and they are around 11m above sea level.  The road between them has some small culverts to allow water to pass through them which can happen in moderate winters.  There are some swallow holes close to the  South ‘Mooneen’ that may have significant flows.

Severe Winter Flooding

With heavy winter rains these marshes will expand but when the South Galway Turloughs of Coole, Garryland, Caherglassaun and Cahermore fill up and overflow, this will flow through Caherawooneen all the way to the sea.   In the winter floods of 2009, there was a flow overland from Caherawooneen to the sea. In winter 2015 however, with the highest rainfall on record and with the creation of an emergency channel (in an effort to alleviate the situation in Cahermore) there was much more substantial flooding in Caherawooneen. There were additional emergency works done to keep water flowing through some pinch points in Caherawooneen/Loughcurra

This was the extent of the flooding when the Cahermore channel was flowing.

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This flow lasted several weeks and is captured on some excellent done footage by Sean Brady Aerial photography.

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Flow at Dungory East.

If we look at this in more detail we see the water overflowed from the Cahermore emergency channel to Caherawooneen South over the road, made its way across several fields and flowed across (flooded) the Caherawooneen North road.

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From Caherawooneen North, the water flow became troublesome as it gathered in a field in Loughcurra north that was surrounded by higher land and had literally no way out. The levels kept rising so emergency channels were cut through in several places and several walls had to be removed to keep the water flowing.  These ‘Emergency channels’ are highlighted in red and removed walls in orange on the diagram below.

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This shows the emergency channel (long red line) in Caherawooneen.

From then on, water flowed from Caherawooneen-North through Loughcurra.

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Flows from Caherawooneen North, through Loughcurra North (Insert are snapshots from drone images from Sean Brady Aerial Photography)

Once the water could flow through Loughcurra then it had a more or less a free run from there to the Ardrahan road, to the Ballindereen road  to the sea beside Dunguaire Castle.

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These emergency works succeeded in keeping the water moving from Caherawooneen to the sea.

Flooding Impacts

One of the first things to highlight in Caherawooneen and Loughcurra is that in 1995, 2009, and 2016, no houses were flooded – this is mainly farmland.  From Cahermore, these lands are more or less (with some exceptions highlighted) downhill to the sea. There are however several other impacts to consider.

Firstly, both Caherawooneen roads flood and this restricts access to many families in the area . For instance, in order to get to Gort, and because the Cahermore road was closed, people had to go via Kinvara and Ardrahan adding an additional 14km for a round-trip to Gort.  The same was true for many farmers in the area as access to the land the far side of floods could require an additional  journey and in some cases would require an additional 20km round-trip journey to tend the farm.  The two Caherawooneen roads were cut off for over 100 days.

The second major impact was on farmland where over 150 acres of land flooded for over a 3-month period.   This has both short-term and long-term impacts. The short-term is the land is unusable for almost the entire year and yield is well down on the farm. The long term impact is that it takes time for fields to recover. The following is a photograph taken exactly 1 year after the floods and you don’t have to be a rocket scientist to guess where the flood water level was as the yellowed grass on the right marks the flooded land.

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The emergency works carried also had many impacts.  Upstream in Cahermore an emergency channel had to be dug to save many houses there. This brought more water into Caherawooneen (an additional 3m3/sec)

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The emergency channel at Cahermore (Courtesy of Sean Brady Aerial Photography)

From talking to local farmers, another big impact here was not necessarily the floods, but the emergency works. When emergency works are done during flooding then the soil was removed while the water was flowing.  The underlying soil had no protection and was washed way destroying the land and bringing a lot of sediment downstream.

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Emergency works carried out in Caherawooneen to alleviate flooding upstream (Courtesy of Sean Brady Aerial Photography)

When the flooding receded the farm land was damaged significantly and in some cases was not put back to it previous state. The following land in Loughcurra used to be a normal field but with the emergency works completed, this is how the land looks 1 year after the floods.

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This land in Loughcurra used to be normal field but was used for emergency works in Caherawooneen

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Even some emergency channels that were put back didn’t leave land in same condition

One key worry of the farmers is that even with land that was put back to its ‘original state’ but not done to a good standard and it would threaten single farm payment subsidies as there are strict guidelines to conform to.

The emergency works were absolutely necessary and did save houses and it’s a credit to all concerned who enabled this – from the land owners, to Galway County council, OPW, our elected representatives, neighbours and friends.  We have to make sure though that the people that gave up their lands don’t end up in the same situation again. They, like everybody else, need a proper solution for this flooding situation rather then be faced with future emergency works that will impact their farms

Solution

The good news is that everybody could benefit from a proper solution to get water from Cahermore (and hence South Galway) to the sea but this needs to be done properly.  There was a preliminary study done in 2011 by Jennings-O’ Donovan and they highlighted in the South Galway Flood report a permanent overground channel from Cahermore to the sea. This is a snapshot of that report.

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This also provided some indicative levels of a channel here:

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  • (D)is Caherawooneen South Road (11.12m above sea level)
  • (E) is Caherawooneen North Road (9.09m above sea level)
  • (F) is the Ardrahan road (4.61 m above sea level)
  • (G) is the Kinvara Ballindereen road (3.25m above sea level)

This channel proposal was over 3 meters deep, and 3m at base with sloping sides. It also indicated the length of the channel from the South Moneen (D) to Kinvara Bridge at around 3 km.

This was a very preliminary proposal and didn’t progress because of Cost-Benefit issues.  The new solution proposal may be similar to this but better hydrology modelling after the 2016 floods will give a better understanding of channel sizing etc.

What is interesting is if we plot the course of the flow of water in Winter 2015 and the route the emergency works have taken. The diagram shows this route as a blue dashed line and it’s quite close for many sections of it but there are some deviations where the emergency works were carried out.

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Sometimes I have to remind people that this is not a channel to drain Coole lake to the sea. This is a channel that acts as a storm drain that only flows whenever there are severe rains in South Galway and would remain dry otherwise.   Like any good storm drains, it should be properly sized, with proper culverts to contain and transport the necessary water safely to the sea. It’s now up to Galway County Council and their engineering consultants to get a proper overall solution designed and implemented.

Summary

Caherawooneen plays a vital role in South Galway flooding dynamics and it is the last route that water takes to the sea.  Flooding tends to happen in Caherawooneen when there is severe winter rains in South Galway. In winter 2015 the normal flooding however was exacerbated by the biggest rainfall that the South Galway has ever experienced and an emergency overflow channel from Cahermore as opened that caused more flooding in Caherawooneen.   Emergency works took place in Caherawooneen/ Loughcurra to keep the water flowing to the sea.  The main impacts were on access and farmland and in particular the state of the land post flood and post emergency works.

The water finds the easiest route and has clearly marked its path. We need a properly designed channel that will take the water from the lower South Galway basins during severe winter rains. The channel (or Storm drain) should benefit many communities of South Galway including the communities of Caherawooneen.

People have been repeating for years now – ‘It needs to start at the sea’ – This is the place that South Galway flood relief needs to start and this should be one of the first parts of the project to complete.

David Murray

[PS : Special thanks to Joe Keane for bringing me around the area!]

The Cahermore Situation

The following article looks at the flooding situation in Cahermore which was badly affected by flooding in 1995, 2013,  2009 and again in winter 2015.

Cahermore is located close to Kinvara between Cahermore cross and Kinvara.  Cahermore Cross connects Kiltartan to Kinvara as well as Labane/Ardrahan and Garryland-Tierneevin.   It is therefore a very important area for access in South Galway which was compromised a great deal with roads blocked for 110 days in the 2015 winter floods.  The Cahermore area has close to 20 households in or directly around it but from an access point of view it would have a substantial impact when blocked.

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What is the hydrology of Cahermore?

Cahermore contains a dry Turlough which means that in the summertime there is rarely any standing water except for a few ponds that are used to water cattle.   As you can see from the diagram below, there is no water body in Cahermore in summer levels  sometimes even in normal winters.

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This site also has a connection with Caherglassaun and when Caherghassaun lake starts to rise Cahermore will also rise through many small springs.   In and 1846 map you can seen  McInerney’s old farm from and a small path to a well in the South.  (This used to have steps down into it)

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Severe Winter Rains

In the past 20 years, during severe winter rains, the situation in Cahermore becomes critical. The Turlough rises initially through springs but when Caherglassaun starts to overflow,  the levels of Cahermore starts to threaten roads, homes and farms.

The critical aspect of Cahermore is that it is one of the last of the South Galway basins to fill with no major connection to the sea and is effectively land-locked meaning water will continue to rise and cause chaos in the community

History of Flooding

From a historical perspective McInerney’s farm has never had a history of flooding, and only since 1995 has flooding become an issue here.

Martin McInerney clarifies the history of flooding. “This farm has been in our family for 10 generations and in those 10 generations, I’m the only one that has had to deal with flooding.   The floods came in 1990 into the sheds and we relocated them to higher ground but the flooding is getting worse and worse and last winter it flooded not only my farm and farm buildings but also my home. The water was never as high.   Imagine that the recent flood levels would have been up the thatch in my grandfathers house – having never been flood in any of that time.   I’ve heard stories of the the ‘night of the big wind‘ in winter 1911 but never a mention of a bad flood.   This situation has to be man-made  since 199 and something needs to be done about this.

When you look at older maps e.g. 1836 there is a section of Cahermore that has been marked ‘Liable for flooding‘. This is an area of about 20 acres and consistently floods in wet winters for 4 to 6 weeks (at the longest).  This is shown in the dotted lines.  This line constitutes a ‘regular’ flood and this is the actual Turlough boundary.

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During the Winter of 2015 the flooding extent was approximately the following:

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As you can see the Turlough levels were way above the 1846 levels and this caused the flooding of homes, farms and roads.    The levels reached in Cahermore were 13.51m above sea level .The following pictures summarize the Cahermore Story (Courtesy of Sean Brady Aerial Photography)

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Why is Cahermore flooding

The easy to say answer is ‘global warming’ but there a lot more at play here.  As we have seen in previous blogs water is getting off the Slieve Aughty’s quicker that before and flood remedial work done in Gort (and channeled to culvert at Kiltartan)  is filling the lower basins much faster and with greater volume of water (Coole, Caherglassaun and Cahermore) – This is  a real threat to the Cahermore community.

The Emergency Channel

In winter 2015, as the water continued to rise, the only potential outlet was around Adrian Glynn’s house was in Cahermore.  Water was already seeping under the ground at the back of Glynn’s making its way to Caherawooneen and the sea at Kinvara.  There was a mound of rock though beside the house that was holding back water.

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A lot of credit has to be given to Adrian Glynn to allow work to be done on this channel. He, and his family were very accommodating  with allowing a channel to be dug right at the back of this house, through his land. A gentleman!

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The Cahermore Channel  in full flow – Courtesy of Sean Brady Aerial Photography

Cahermore was rising several inches per day but this channel tapered it and eventually the levels stabilized within 5 days and around 2 weeks it started dropping.  There is no doubt in my mind that this channel had a significant impact on the saving of a complete community from flooding.

Impacts of Flooding

Cahermore was one of the communities affected the most seriously as the level of the Turlough impacted directly on the area.

  • There were 4 houses flooded and an additional 5 houses under water (but protected with sandbags and pumps etc) . A further  5 house were badly threatened.
  • Over 14 septic tanks flooded
  • Several farm buildings with slurry tanks were flooded and over 240 acres of farm land was flooded and over 17 farmers affected
  • Consequently the water in the area was contaminated
  • The road was closed for 106 days. This had a severe impact on parents with kids going to Northampton school and Seamount College and the community of Kinvara  as a whole and farmers having to make their way to get access to lands on the far side of the flood

Cahermore is a SAC (Special area of conservation) which, due to the flooding of roads, septic tanks and farmyards, would have had considerable pollution.  (you can see the slurry from the farmyard below flowing into the Turlough.

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Community response

One thing that I wanted to highlight is the Cahermore community response to the flooding.  The level help and support for people in crisis was incredible.   From Adrian Glynn’s selfless attitude to digging through this land to alleviate floods to the youth of the community – filling sandbags, manning pumps, helping neighbours – Cahermore – It’s a credit to ye!

Solutions

From the moment that we got the storms, Cahermore was always in trouble and the trouble starts several weeks after the rains. There is simply no way for the amount of water to get to the sea underground and it swells the Turloughs and spills overground. The key solution is simple – Keep the maximum turlough level to a safe level (for all concerned) and get the water safely to the sea. The implementation of that solution may be more complex but still not rocket science.

What is a safe Level for Cahermore?

A safe level for Cahermore would be a level that doesn’t threaten homes, farms or access (and consequently the environment). In winter 2015, the maximum level of Cahermore was 13.51m and this is too high.  For instance, if we look at an OS map you can see a 10m contour (highlighted in red) . It doesn’t come near any house. (It still comes near a road, but this may be a special case)

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From an environmental point of view, the NPWS, were of the opinion that if the Turlough was kept within this boundary, it wouldn’t have an adverse affect on the integrity of the Turlough, consequently, maintaining this at a maximum level would have positive benefit  on this SAC and other downstream areas.

Channel to the sea

The complex part of the solution is that in order to maintain this type of a level there needs to be a dedicated overflow channel to the sea, through Caherawooneen and there needs to be a proper sizing and overflow levels.  E.g.  the road at Caherawooneen is at 11.12 m.  So maintaining Cahermore at e.g. 10m would mean deeper and more costly channel.   There would need to be  balance between a deep (and expensive and disruptive channel) and cost efficient, but not very flow-efficient channel.   This balance is what we will need to keep an eye on as a solution progresses.

Today a temporary emergency channel is in place that can be opened to let some small flow out of Cahermore but this should not be seen as a long-term solution – it’s simply not big enough.

Summary

In severe winter flooding, Cahermore gets very badly affected as it takes overflow from Coole and Caherglassaun and there is no dedicated outlet.  The flooding has had a significant impact on homes, farms, access, health and the environment.   This situation is exacerbated by more recent upstream flood alleivation work and cannot be allowed to repeat.  The maximum Turlough level for Cahermore needs to be maintained at a level that eliminates these threats and the only way this will happen is to provide a dedicated ‘storm drain’ from Cahermore to the sea.  This is the first thing that needs to happen in overall South Galway Flood relief scheme

 

David Murray