Artemis II On Schedule

Artemis II crew. Image credit: NASA/Kim Shiflett

The Artemis I mission, launched in 2022, involved sending an uncrewed Orion spacecraft into orbit around the Moon and bringing it back to Earth. Artemis II will be a crewed mission, launching four astronauts into a free-return orbit around the Moon and back to Earth, the first time humans will have been in lunar orbit since 1972. The mission had been delayed until September 2026 due to technical problems, but has now been brought forward to April of next year or possibly earlier. NASA's Orion spacecraft comprising of a command and service module sits on top of the unimaginatively-named Space Launch System (SLS), the equivalent of the Saturn V rocket used for the Apollo program. The 8.4 m (27.6 ft) diameter, 98 m (322 ft) tall SLS is a two-and-a-half-stage rocket, powered by engines that burn liquid hydrogen and liquid oxygen, assisted by two solid rocket boosters.

Turlough Hill Transmission Lines

Twin 220 kV lines crossing the mountains from Turlough Hill hydro station. © Eugene Brennan

One of my cycles back in mid-August (the long days of summer seem to be a distant memory now) was from Kilcullen to within a few miles of Turlough Hill. This is the location of Ireland's only pumped storage power station. When there's a surplus of power which the grid can't use, pumps at the station send water to an artificial lake located on top of the mountain. Once there's a demand for power, the motors and pumps switch function and become turbines and generators, the turbines driven by water as it rushes down through penstocks (large pipes) to a natural lake, located at the base of the mountain. Turlough Hill power station is net inefficient (power out is less than power in due to losses in the system). However it acts as a buffer on the grid, being capable of supplying power within a short space of time, unlike conventional thermal power stations. Battery energy storage systems (BESS) will replace this type of system in the future, to cope with the erratic nature of renewable energy sources such as solar and wind generation. Although getting planning approval for BESS facilities can be difficult (as we saw locally), it's probably a lot easier than getting permission for a facility which would end up "ruining" a mountain as some would see it, or planning permission to flood a valley for a hydro station. 

My route. It's roundabout to avoid very steep hills and busy roads. © Eugene Brennan

 

Maps courtesy Open Infratructure Maps.

Maps courtesy Open Infratructure Maps.

When I'm heading for Turlough Hill, I turn right just before the left turn for Valleymount on the Hollywood-Glendalough road. This road is a cul-de-sac that runs along the King's River for around three miles before becoming a track that meanders through open landscape (with nice scenery) and forest. It's possible to cycle for another three miles or so over logging trails before rejoining the road to Glendalough, near the bridge over the King's River.  Twin 220 kV transmission lines from Turlough Hill run parallel to the King's River, on their way to Dunstown 400 kV Substation and Maynooth 220 kV Substation. (One of the transmission lines from Turlough Hill and another from Great Island Power Station in Waterford cross Boleybeg Hill near Branncockstown on their way to Dunshane substation.) These are transmission lines, carrying power long distance throughout the country. Distribution lines carry power locally, to and from smaller substations that serve towns and villages.

Forestry trail that runs parallel to the Kings River. © Eugene Brennan

Mountain rowan. © Eugene Brennan

The 220 kV transmission lines run along the cul-de-sac road that branches off the Hollywood-Glendalough road. © Eugene Brennan

Twin 220 kV lines crossing the mountains from Turlough Hill. © Eugene Brennan

Trail through forestry. © Eugene Brennan

All Good

Created by Grok

 

Real Time Displays at Kilcullen Bus Stops

Image © Google Maps

I asked the NTA for information on whether real time passenger information displays could be installed at bus stops. This was the response:

Case #402630

Dear Eugene,

 

I refer to your recent correspondence regarding the provision of an RTPI (Real Time Passenger Information) unit at the following bus stop locations, images attached, which was forwarded to the National Transport Authority (NTA) to respond to you:

 

• stop number 136431, Kilcullen (Opposite Service Station), Castlemartin, Co. Kildare; and
• stop number 132641, Kilcullen (Outside Service Station), Castlemartin, Co. Kildare.

 

At present there are over 12,000 bus stops in Ireland serving a variety of bus services including local, urban, and regional bus services across a variety of operators.  Because of the costs associated with the provision of on-street RTPI signage, it is not feasible to provide Real Time Passenger Information (RTPI) signs at all bus stop locations. 

 

One of the main reasons for these costs is the need for an independent power supply for RTPI signs.  These signs require an electrical supply in order to operate and there is a prohibition under statutory regulation, derived from European legislation, that prevents the NTA from taking an electrical connection from an existing public lighting power supply, even where convenient and adjacent.  Instead, separate independent electrical connection is required from ESB Networks, which can often necessitate extensive trenching, road crossings, and major reinstatement work, all contributing to significant costs.  As a result of these costs, and to ensure value for money, it is intended to only provide RTPI as an integrated sign within a new bus shelter or, depending on suitability, within an existing bus shelter that already has an independent power supply and has been designed to accommodate an integrated RTPI sign.  In that way, a cost-effective single integrated power supply can be provided, powering both the bus shelter lighting and the RTPI sign. 

 

Regarding the aforementioned bus stops, we note that currently there are no plans to install bus shelters at the bus stop locations. As part of a past programme of shelter installations throughout County Kildare the feasibility of installing shelters at both stops was assessed. However both locations were discounted for technical reasons, such as sight line safety issues relating to stop number 132641 and insufficient footpath space relating to stop number 136431. Additionally, we note that the bus stops are not ducted and connected to the ESB network.

 

Notwithstanding the constraints and limitations outlined above, it is worth noting that all of the information available on such RTPI Displays is also available through the NTA’s app for RTPI. The “TFI Real Time Ireland App” and the RTPI The App is available free on Apple App store and the Google Play store and combines all real time information services from Bus Éireann, Dublin Bus, Go-Ahead Ireland, Iarnród Éireann and Luas.  All bus stops have a number at the top of the bus pole indicating the particular bus stop number.  Simply inserting that number into the App provides the RTPI information on bus arrival times at that stop. The App and the RTPI units are supported by the same back of house data feed. There is no difference between the information contained on RTPI units and App. We would encourage travelling passengers to download and trial the app to get familiar with all the real time information available to passengers at each bus stop. Additionally, we also note that when passengers scan the QR code contained on the timetable panel it should bring them to that particular stop number within the TFI Live app.

 

We regret that we are not in a position to provide a more positive response to this request at this point in time for the reasons outlined above. We trust that the above information is of assistance and clarifies the matter.

 

This mailbox has a no-reply functionality so, if you have any further questions on this, or anything else, please don’t reply here, instead, please email info@nationaltransport.ie, quoting this reference number : Case #402630, to ensure a response.   

  

We’re here to help. 

 

I hope that this is helpful and wish you safe onward travels 

  

Kind Regards 

Josephine

National Transport Authority   

Chapel Lane, New Ross

Image © Google Maps

Unlike the UK, where medieval houses are plentiful, we have relatively few pre-18th century houses in Ireland. There are castles dating back to medieval times, but there are few, if any, "ordinary" houses from the medieval period, as we would think of a house today. However, fortified tower houses exist. One probable reason is that there was no substantial middle class who could afford "proper" houses, built from timber or brick and most people were poor and lived in mud cabins. Or maybe the climate was hostile to the half-timbered houses like those that still exist in the UK (if they even existed here), and they decayed over the centuries. Most of the houses in the country date no further back than the Georgian era, which extended from 1714 to 1837. There are some examples of Queen Anne style architecture, such as the Red House in Youghal, Marsh's Library in Dublin and The Rubrics in Trinity College. These were built in the 1710s and have a distinctive "doll's house" appearance. A few Tudor/Elizabethan-era buildings exist, such as Rothe House in Kilkenny; Ormond Castle, a manor house in Carrick-on-Suir; and Myrtle Grove, Sir Walter Raleigh's home in Youghal. It's possible also that some houses were later "Georgianified", their older fabric concealed beneath a more modern facade. That's the case with some of the so-called "Dutch Billys" in Dublin, a pre-Georgian architectural style brought by the Huguenots, Protestants who fled persecution in France around the end of the 17th century. So to cut a long story short, I came across this some time ago. I think it was Colm Moriarty, a Wexford-based archaeologist who mentioned the street in New Ross in a social media post. The facades at the front are plain-rendered, but the back of the terrace of houses reveal the medieval origin of at least one of the buildings.

 

Google Maps link to Chapel Lane in New Ross here 

Maps for Council Workers

Image © Google Maps

Apparently when we report road or other issues on the KCC portal and specify the location of the problem, repair crews just get a description, but not the map pinpointing where they have to fix them (there's an option to tag the position on a map when making a report on the portal). I had a long discussion with a repair crew a month or so ago and got a great insight into how they feel about this and other things. If someone reporting a problem doesn't clearly specify road numbers and distances from landmarks, obviously it can be difficult for a repair crew to find the problem. Saying that it's "just down the road from Johnny's house" or similar isn't very helpful. A point on a map would be more logical (assuming the person who made the report zoomed in sufficiently to accurately place a tag). Reading a map is hardly rocket science and I'm sure KCC can train workers to do so.

 

Maybe someone can let me know whether the tarmac is broken up and gone from around this drain opposite LaTouche Cottage in Brannockstown so I can report it? I make mental notes of these things when I'm out and about on the bike, but I've got a head like a sieve and forget where I've seen the defects. I don't want to make a false report. A cyclist could easily lose control if they hit this. It was ok last August when the Street View imagery was taken, but as far as I recall, the tarmac fill around the drain has now disintegrated.

A Little Ladder Logic

Ladder logic program. © Eugene Brennan

Just found this among documents I was going through after getting the oil boiler serviced last week. I had forgotten all about it. The electrician made a minor cockup when wiring the controls for the dual oil/solid fuel heating system 9 years ago. So I had to go off and look for a CAD package to draw a ladder logic diagram for him, showing how it should have been wired. (He had his own ladder logic diagram, but it made more sense for me to draw a new one, rather than trying to explain the error in English). Ladder logic is a schematic system for showing the wiring in an electrical/electromechanical system, input devices such as switches and sensors and output devices, e.g. motors and relays being shown as symbols on a diagram. It has evolved into a graphical programming language, the graphical program used to control programmable logic controllers (PLCs). These are basically modular, industrial control computers, built into a box, with terminals for connecting inputs and outputs. A computer can be connected for programming and they can be linked-to by various computer networks.

I'm rusty on this stuff. It's a shame when you learn stuff, and then forget it all if you're not applying the knowledge on a daily basis (I never really used this practically, even though I studied industrial automation).

See if you can understand what this does. Hint: MV1, 2 & 3 are zone valves, R1 & R2 are relays. SF is solid fuel.

Heritage Week Sunday Cycle

Historical buildings in Ballitore and Calverstown.© Eugene Brennan

My Sunday cycle this week was supposed to be to Kilkea Castle, but it was 4 pm by the time I set out and I changed plans midway. (Sometimes I make up the route as I go along and let the bicycle decide). Usually on the steep road out of Crookstown heading west towards the Athy road direction, I turn left for Mullaghmast at the top of the hill. I travel cross country to Kilkea this way, crossing the new N78 Athy Link Road at the bottom of Mullaghmast Hill, and then take a right just before the Moone Inn. On Sunday, I took the second turn after the Mullaghmast turn on the Crookstown road. This leads to the Burtown area on the new N78. I travelled a few miles east on the N78, and then exited for Ballitore. In the village I took some photos of the historic Quaker buildings including the Meeting House and Mary Leadbeater's house, now a library and museum. Leadbeater (1758 - 1826 ) was a Quaker and author who lived in the village and documented events during the 1798 rebellion. 

Mary Leadbeater's house, now a library and museum. © Eugene Brennan

A school established in 1726 by Abraham Shackleton. It's now a Quaker meeting house. © Eugene Brennan

Next I headed to the outskirts of the village and the location of Ballitore Mill. This a large, ruined structure, built in the early 19th century. An EPA hydrometric station that monitors water level and flow is located on the River Griese, which runs alongside the mill. The Griese in addition to powering this mill also powered a second mill in Ballitore, located down a cull-de-sac in the village. I headed back on the old section of road towards Crookstown. This was the original Carlow road before it was replaced by a wider section several decades ago. It's amazing how the ditches of a road that's no longer used begin to creep inwards and the accumulation of leaves and other debris begin to return it to nature, obscuring the tarmac. 

Ballitore Mill. © Eugene Brennan

Ballitore Mill. © Eugene Brennan

EPA hydrometric station. © Eugene Brennan

From Crookstown, I headed back towards Calverstown via Narraghmore Bog. I took the road that runs alongside Crookstown Millview AC's track and then turned off that to pickup up the Narraghmore - Calverstown road. I've always intended to visit Blackhall Castle, and I've passed the entrance multiple times over the decades, so I decided to investigate it on Sunday. A long, wooded lane leads down to the castle, situated in the grounds of an old farmhouse, probably dating to the Georgian period and owned by Jeffrey and Naomi White. The owner, Naomi, and a barking Cocker Spaniel greeted me and Naomi explained some details about the ruin. The four story castle was built by the Eustace family in the 16th century and appears to have a large , impressive fireplace on the fourth floor. Unfortunately half of the castle collapsed in 1999, due to instability in the structure. Naomi told me they had secured a grant to stabilise the structure, but it's a shame the collapse happened before this work could be done. There's also a "Sheela na Gig" carving which was luckily recovered from the rubble after the collapse and is now mounted in a ground floor wall. More information on Blackhall Castle is available on the Irish Historic Houses blog here.

Blackhall Castle. © Eugene Brennan

 

Blackhall Castle. © Eugene Brennan

 

Sheela na gig carving. © Eugene Brennan

 

My cycle route. © Eugene Brennan

I Present to You for Heritage Week

Items found in the garden. © Eugene Brennan

.....my archaeological discoveries from the garden. Found while digging and doing construction work over the last few decades. Probably nineteenth century stuff. My theory is that rubble from the demolition of the Carlow Stables was spread out to level the ground during construction of the Nicholastown housing estate and that's where some of these fragments may have came from. During the era when a Bianconi coach service ran from Dublin to Cork, via Clonmel, horses were replaced at intervals along the way. The Carlow Stables in Kilcullen was one of the relay sites. The building was located just before the first turn into the estate, heading south. Some of the fragments I found were rough pottery with glaze, so these could be pre-nineteenth century and not manufactured in moulds or by machine. One piece has shallow grooves, possibly made by finger marks when the pottery was turned on a wheel. The top of a flagon came from outside the wall of my house, dug up when the council was fixing a broken water main almost 20 years ago. It's embossed with the text "Price Bristol". That grass bank outside the house probably contains a treasure trove of items, lost and discarded over the centuries since the road and the trail which probably preceded it has been in existence. I also found a piece of red brick, three feet under the ground, when I was digging a soakaway in the front lawn, but there were no houses in the area before the estate was built. The triangular tile-like objects were found when I was digging the foundations for my gate piers a few years ago. Not sure what they are.

Painting Tip Related to Science

Cleaning a paint brush in white spirit. © Eugene Brennan

I've been painting my front door, something I've been putting off for a couple of months. Painting requires preparation and then there's all the cleaning up to do afterwards. The trend now is towards the replacement of oil-based paints for wood and metal by water-based formulations. Presumably this is an eco-driven thing, to reduce emissions of volatile organic compounds (VOCs) into the atmosphere or landfills when paint containers are discarded. I'm not convinced water-based paint is as durable as oil-based types, however it does make the cleaning of brushes easier. Cleaning oil paint off brushes requires the use of a solvent such as turpentine, white spirit or kerosene. Here's where the science comes in, but first some background knowledge on the subject of mixtures. When two or more substances are combined together, the result is known as a mixture. There are several different types of mixtures. A solution is a mixture of a soluble solute, e.g. sugar or salt in a solvent, e.g. water. The solvent doesn't have to be water: another example of a solution is light oil or fuel additive in a solvent such as petrol. Atoms in a mixture don't combine chemically, they just closely intermingle, but don't bond with each other. Another type of mixture is a colloid such as milk or paint or a suspension such as muddy water. The only difference between a colloid and a suspension is the size of the solid particles and the time it takes for them to settle out, if they ever do. Mixtures don't have to be combinations of a solid and liquid; they can also consist of two or more solids— such as sugar and salt, or stones and sand. Gasses also combine to form mixtures. So air is a mixture of nitrogen, oxygen, carbon dioxide and small traces of inert gasses such as neon, argon and xenon.

Often in a lab, it's necessary to separate the individual items in a mixture. The processes used are also employed in industry. Filtering is one technique, but that only works for non-solutions. You can't remove salt from salty water for instance by filtering the solution. That's because the salt exists as individual molecules of sodium chloride in the solution and they would just pass through any filter medium. So to extract it, evaporation of the solvent, water in this case, is the separation technique used, leaving the salt behind. If the mixture is a colloid or suspension, the particles are much larger and so filtering can be used. In a lab, this can be done using a funnel and filter paper. On an industrial level, e.g. in a water treatment plant, muddy water is filtered through sand beds. Hence the colloquial term for the Ballymore Water Treatment Plant, the "Filter Beds". Distillation is another separation technique used for example to separate a solution of alcohol and water when making spirits. Alcohol and water boil at different temperatures: 78.5°C, for alcohol, while water boils at 100°C. Heating a mixture of alcohol and water above 78.5°C causes the alcohol to boil off, leaving the water behind. A condenser or "still" is used and cold water circulating in the condenser cools the evaporated alcohol, creating a condensate, which is then collected. Yet another separation technique is decanting. The principle is simple, give a suspension enough time and the suspended particles will settle out. That's what happens in the BWTP and muddy water from the reservoir is given sufficient time for the suspended mud particles to settle out in tanks. The clearer water from the top is pumped off and filtered through sand. That initial treatment removes material that would quickly clock the filter beds. And that's what I do with the white spirit that I use for cleaning my paint brushes: instead of discarding it, I collect it in a 5 litre container and after 6 months or more, all the suspended solids settle out, leaving a reasonably clear solution. Then I can decant off the white spirit as necessary to fill bean tins for washing paint brushes. The decanted white spirit isn't perfectly clear, but good enough for cleaning brushes.

© Eugene Brennan

Attacking the Brasses With Acid

Shiny fittings on the newly-painted front door, the result of hours of polishing. © Eugene Brennan

Painting is something I tend to procrastinate on and life is too short for cleaning brasses regularly. I do a good job of cleaning the hardware on the front door every two or three years when I paint it, but then I only polish the brasses a couple of times before I lose interest and have more pressing chores to attend to. After three years of non-cleaning, a thick layer of oxide builds up on the fittings which takes several hours to remove with wire wool and Brasso. (Brass is an alloy of copper and zinc, so the tarnish is zinc oxide and copper oxide). There may be other compounds making up tarnish such as acetates (The green patina on domes of public buildings and the Statue of Liberty, known as verdigris, is copper acetate. This forms naturally or is created artificially by using acetic acid on the copper sheeting, pre-construction). Anyway to cut a long story short, from my school chemistry I knew that acid dissolves oxides and turns them into salts. Someone gave me half a 5 litre container of Ecokem phosphoric acid they didn't want. Phosphoric is used for cleaning rust (iron oxide) off iron and steel and descaling lime build-up from sanitary fittings. So I tried the stuff and it did a reasonable job of quickly removing the tarnish. 

Phosphoric acid, a product used for descaling. © Eugene Brennan

This is a faster method than using wire wool or Brasso, but I'll use the latter to further clean and polish the brass (Brasso contains a mild abrasive). I noticed the brass had turned pink and suspected that the acid had reacted to a greater extent on the zinc in the brass alloy, dissolving it and leaving the copper behind. My suspicion was confirmed by Grok. After washing the acid off, the brass turned black and brown when it dried. Not sure what produced that chemical reaction. Will have to ask Grok for a follow up.

The acid dezincified the brass, leaving copper behind. © Eugene Brennan

Edit: Grok said it's copper oxide, formed by the rapid oxidation of porous copper after dezincification by oxygen in the air or rinse water. It transpired that the dezincification was superficial and I used Brasso to finish the job, leaving the fittings perfectly shiny.

Grok confirmed the dezincification. © Eugene Brennan

 

De Burgh Woodland Gardens and Naas Mills

Image courtesy and © Tailte Éireann.

I was late as usual heading out on my Sunday cycle, and this week it was a relatively short trip to Sallins after the long cycle to the Glen of Imaal the previous weekend. My sister had informed me that the De Burgh Woodland Gardens were open again this year. The woodland area, located just off the Sallins Road on Mill Lane and once part of the De Burgh Oldtown estate, has been developed over the last couple of years by Kildare County Council, the land having been transferred to Naas Town Council in 2011. I guessed the gardens would probably close around 5 pm and sure enough when I got there at 4:40 pm, I only had five minutes to walk the trails by the time I got my bike locked, and removed bags and lights and all the other stuff that could easily be stolen. I didn't get a chance to take any photos, but the place looks nice, although quite dark because of the tree canopy. It is woodland of course, although there's a pond at one end, which I didn't manage to see. As usual when I visit these places, I often investigate the area the next day on Google Maps and Tailte Éireann's Irish Townlands and Historical Map Viewer to find out the historical function of some of the structures I might have noticed. On 19th century maps, a large rectangular pond existed to the right of the entrance to the park. From satellite imagery this seems to be overgrown and from what little can be seen on Street View over the wall from the vantage point of Mill Lane, it appears marshy and populated by irises. The pond was fed from a mill race or stream that originated on the Ballymore Road and this is still in existence. On the c.1900 25" OSI map, the mill race is shown running alongside the Union Workhouse (now the old part of Naas Hospital). This is the stream that was dammed to create the lakes at Lakelands. The mill race then continued to Corban's Mill (located near what was Lawlor's Ballroom) providing power to it before taking a sharp left, running under Corban's Lane and at the back of St. David's Castle. From there, it ran alongside what is now the John's Lane car park (which used to be the Superquinn overflow car park), before becoming a culvert running beneath main street and emerging to the surface a couple of hundred metres away at McCauley Place. From there, it continued parallel to the Sallins road towards a corn mill (with associated mill pond), shown as "Fryar's Mill" on the 25" map, before running under Mill Lane into the De Burgh Woodland Gardens.

Image courtesy and © Tailte Éireann.

 

Image courtesy Google Maps.

The Kildare County Council owned De Burgh Woodland Gardens are open Thursday to Sunday, April – October, 9am – 5 pm. More information here.

Map images courtesy and © Tailte Éireann. 

Solar Panels, Local Mines and an Adit in Hollywood Glen

© Eugene Brennan

I cycled up to the Glen of Imaal yesterday afternoon. My route took me via Kennycourt to Grangebeg, Lemonstown, Hollywood and then up the steep road from Donard to the glen. I usually go this way because the road is quieter, with very little traffic and then return via the busier but more downhill Knockanarrigan road.

The L8333 road from Hollywood to Donard runs parallel to the N81 and through the picturesque Hollywood Glen. It's is one of my favourite places in west Wicklow, lined on both sides by tall pine trees and rocky crags in places.  A planning application has been lodged recently to Wicklow County Council on behalf of Wicklow Renewables Ltd for a solar PV development  and battery energy storage system (BESS) facility in the area. According to the planning application, the site will cover an area of ca. 65.4 ha and consist of an array of solar panels, 192 BESS units comprising 22 modules, a 38 kV substation and other ancillary works. The location of the proposed solar development is on raised ground behind the treeline in the photo below. The boundary of the proposed development extends southwards and to the west towards the N81.

Hollywood Glen. © Eugene Brennan

Notice about planning application by Wicklow Renewables Ltd. © Eugene Brennan

Mines Local to Kilcullen

Apart from the Modubeagh and Gracefield coal mines near Wolfhill, one of the nearest mines to Kilcullen was the Deerpark Colliery near Castlecomer, which opened in 1924. Anthracite, a high carbon coal, also known as "Kilkenny Coal" and used before coke for ore smelting, was extracted from the  mine. This was  transported on a dedicated branch line that ran through Castlecomer and joined the Waterford & Maryborough branch of the GS&WR, itself a branch of the Dublin to Waterford rail line. The Deerpark colliery closed in 1969.  The region south of Ballylinan, (located 6 km south of Athy) including parts of counties Laois, Carlow and Kilkenny, is riddled with the remnants of now closed coal mines.  These mines tapped into several anthracitic formations that are part of the Leinster Coalfield. Mining has also taken place in Wicklow since ancient times and one of the most well known mining areas is around Avoca, where sulphur, lead and copper were extracted. Lead was mined at Glendalough and also in its sister valley, Glendasan.
A useful resource is the OPALS (Online Prospecting Application Licensing System) interactive webmap, from the Department of the Environment, Climate and Communications, which  provides locations and information on historical and current mineral exploration and mining in Ireland.

OPALS (Online Prospecting Application Licensing System) interactive webmap. Image courtesy and © Tailte Éireann

Hollywood Mine

Halfway between Hollywood and Donard and now overgrown with briars and lady ferns is what appears to be the entrance to an adit. The adit is partially flooded and the echo of water dripping from the roof can be heard. While a mine shaft is a vertical structure, an adit is a horizontal passage that extends sideways into a mine. This is marked on the c. 25" OSI map and is denoted as "Spa Hole" and "Iron Mine Disused". I haven't been able to find any information so far on this working, other than a geological report on the glen that indicates it's a glacial feature, deeply carved by high-energy, water run-off as ice melted. The second map below from Geological Survey Ireland shows audited sites, with links to reports accessible by clicking the link in the pop-up.

Entrance to Spa Hole adit. © Eugene Brennan

"Spa Hole" marked on 25" OSI map. Image © Tailte Éireann

Audited Geological Heritage. Image © Tailte Éireann Geological Survey Ireland

Golden Brown in Laois: Investigating the Barrow Way

© Eugene Brennan

My second long cycle of the year was an 80 km / 50 mile loop on Sunday that took in a section of the Barrow Way. This is a walking and cycling trail along the Barrow Branch of the Grand Canal and River Barrow that stretches a distance of 117 km, from Robertstown in County Kildare, to St. Mullins in County Carlow. My cycling route was cross-country to Athy via Narraghmore Bog, Mullaghmast and the new N78. Then along the Barrow Way from Athy to Vicarstown and back home via Kilberry Bog, the outskirts of Suncroft and Ballysax. Grit trails have been laid along the canal banks in the last decade or so to make cycling and walking easier.

Kildare is a flat county, but the region of south Kildare and County Laois near Athy is characterised by exceptionally large, flat, open fields, almost prairie-like, cultivated with barley in the summer. The golden brown of the corn contrasts with the "big skies" and unobstructed views of the horizon.

© Eugene Brennan

Apart from admiring the scenery along the Barrow Way, I spotted some interesting engineering features. The first was the Camac Aqueduct at Derrybrock in County Laois. This is a three-arched aqueduct, built over the Stradbally River in 1790, to carry the Barrow Branch of the Grand Canal. As far as I know, marl, a soft grey clay, found at the bottom of bogs, was used as a sealer for waterproofing the masonry joints of aqueducts. In the documentary series Hands, marl was also used by one of the operators of Powers Foundry in New Ross for lining the furnace to prevent the casing from being burned by the intense heat. The Camac Aqueduct seemed "leaky", water dribbling from the top of the arches. Maybe this is normal for these structures.

Camac Aqueduct in County Laois. © Eugene Brennan

At Derrybrock Bridge near Vicarstown, I came across an OPW hydrometric measuring station, similar to the Kildare County Council owned and EPA managed one at the Mill Stream bridge on the Mass Path in Kilcullen. While the monitoring apparatus in Kilcullen is somewhat low-key and wouldn't be noticed by the casual walker, the station at Derrybrock is more obvious. A large, and what appears to be a broad-crested, flat-V weir, similar to the one in Kilcullen is used to backup the water so that it rises in level.  The monitoring equipment, powered by a solar panel, projects out of the side of the riverbank. The "V" in this weir is more obvious than the one in Kilcullen, with the arms of the "V" rising up out of the water on both sides.  Various types of profiles are used for weirs: rectangular, parabolic, trapezoidal, flat-V and V-notch, each having their advantages and disadvantages. Flat-v weirs are used for measurements in rivers and streams with low flow rates and narrow stream beds. Some info on the different types and flow calculations here. As  I explained in the article about the Mill Stream hydrometric station in Kilcullen, weirs are used for measuring water flow. A weir causes water in a stream or river to backup and rise in level. By measuring the level using an ultrasonic or pressure transducer and doing some calculations, flow rate can be worked out. This hydrometric data can then be used for planning, water management, flood research etc. Information on the EPA's hydrometric programme is available here. It's part of the National Hydrometric Programme, with other bodies such as the OPW, the ESB and Waterways Ireland also involved in measuring water level and flow. Data from a network of over 1000 hydrometric stations around the country can be viewed on the EPA's Hydronet website.

Derrybrock Hydrometric Station. © Eugene Brennan

Instrumentation for measuring water level. © Eugene Brennan

Flat-V weir. © Eugene Brennan

Flat-V weir. © Eugene Brennan

Weir view from Derrybrock Bridge. © Eugene Brennan