The Crumlin Arm Water Shortage – a continuing problem

In recent years, much criticism has been laid at the door of Newport City Council for lack of maintenance on both the Crumlin Arm and the main line from Malpas North. Whilst a substantial amount of public money has been spent recently on improving the towpath under the Active Travel initiative to provide a safe and convenient route for walkers and cyclists, the visual attractiveness of this route is severely devalued due to the lack of water, coupled with absent regular maintenance of the canal channel, locks, and vegetation.

There has also been much criticism of Newport City Council in social media of late for the absence of water in the section of canal approaching Fourteen Locks. The recent long period of dry weather coupled with scheduled maintenance by Caerphilly CBC and a major leak in the Newport City Council section, which has now been repaired, have all combined to severely impact water levels.

We explain below that it is not a straightforward issue, with the root of the problem lying with highway engineers back in 1968!

The recurring water shortage on the Crumlin Arm is primarily a result of 2 major factors:

The Lack of a Reservoir
Unlike the main-line from Brecon the Crumlin Arm did not have a major river continually feeding it with a water supply. The canal as-built had a main reservoir at Pen y Fan (now Pen Y Fan Country Park Pond) and smaller secondary reservoirs at Hafodyrynys, and Crumlin. Pen Y Fan Reservoir was disconnected from the canal when 3 miles of canal between Cwmcarn and Crumlin was destroyed to construct a new A467/B4591 road in 1968/9; with only short isolated sections of canal remaining. The Crumlin Reservoir was breached by Nant Carn in 1875, causing a number of fatalities, and was never rebuilt. The Hafodyrynys Reservoir was filled in many years ago with its site now underneath a council depot and playing field. The advantage of having reservoirs is that they can obviously store water during wet periods and release it when the canal needed topping up during dry weather or periods of heavy lock usage.

Today the remaining section of canal relies on a few mountain streams to feed it with water. The main supply is from Nant Carn at the very end of the canal at Pontywaun. The feed pipe enters the canal near to the aqueduct. Various other streams and some road drains are also picked up on route down to Newport. The common problem is that during periods of prolonged drought the aquifer dries out, the water table level drops and the springs feeding the streams have a reduced flow or dry up altogether.

With the aid of one of our volunteers, MBACT did conduct a survey as far back as 2013 to try and identify new sources of water. Following the survey, two “easy wins” were implemented. The first was at Newport Golf Club, where a culvert diverting water into the canal had become blocked. At our request this was cleared. The second was at Manor Road, Risca. Here a culvert and weir-board chamber had been constructed in the past to allow for the diversion of a surface water sewer (a combination of mountain spring water and water from the roofs and hard surface areas of the Ty Sign Housing Estate) into the canal.

We discovered that that supply had been turned off by Caerphilly CBC due to the fact that some residents on the Ty Sign estates had illegally connected domestic appliances such as dishwashers and washing machines to the surface water sewer rather than the foul sewer. This had resulted in heavily contaminated water getting into the canal. We approached Welsh Water/Dwr Cymru about the problem, and they responded by sending in a team with sewer cameras. They were able to locate the offending connections, which were subsequently disconnected following action by Caerphilly CBC. The supply has run again until relatively recently when it needed to be turned off again this year; again down to new illegal connections.

We understand that Welsh Water are having to repeat the camera exercise again to identify the source of the pollution before the supply can again be reconnected. This is a shame as this supply provides a good feed to the very area that we need it, but understand the problem as this sort of pollution can result in fish kill.

Canal Levels
The second problem is that we believe that the canal channel has been subject to subsidence at various locations. Not surprising, as it is built on a steep hillside with extensive mining operations in the valley. This interrupts the flow of water down to Newport. What we have found in the past is that if the water level drops even slightly in the Caerphilly section, as it does in periods of drought, it has a substantial impact on water flow to Newport.

The water flow is also not helped by the culverted sections installed over the years at Manor Road, Pontymason Lane and Ruskin Avenue road crossings. Non-existent maintenance and the lack of dredging of the canal channel from Harry Roberts Bridge (the Newport CC boundary) to Ruskin Avenue has also allowed silt and weed to build up, thereby choking off the little water flow there is.

A Solution is Desperately Needed
We have discussed a possible new mountain stream feed with Caerphilly County Borough Council engineers in the past, but this again will not help much if there is a drought. There is an existing stream in Pontymister, which has a substantial flow when rainfall patterns are normal. It is however not a straightforward project. The steam has been culverted through a play area, goes under the road, under the canal and under the old railway sidings area to the west of the canal to emerge high up a stone embankment. So, difficult to solve engineering-wise, expensive, and may not solve the problem in long periods of drought. An added complication these days is the fact that Natural Resources Wales consent would be required to divert water into the canal.

This problem is clearly getting worse due to climate change. MBACT will again be raising this issue with Caerphilly CBC and Newport CC to see if there is any way this situation can be at least helped.

MBACT recently responded to the publication by Caerphilly County Borough Council of a Draft Lower Ebbw and Sirhowy Valleys Masterplan. In terms of water supply we said:

“……The recreational, tourist, and ecological potential of the canal is hampered by severe lack of water during periods of sustained dry weather. This lack of water is particularly felt on the eastern end of the Crumlin Arm where the canal bed dries out with resultant loss of wildlife. The plan should commit the Council to investigate additional sources of water such as mountain streams, and/or the enlargement of the Cwmcarn Forest Drive Lake and its use as a feeder reservoir for the canal in times of drought……”

https://mbact.org.uk/2022/mbact-response-to-lower-ebbw-and-sirhowy-valleys-masterplan/

Until a permanent solution can be found we would urge Newport City Council to clear the overhanging vegetation and dredge the section of canal between bridge 10 – “Harry Roberts Bridge” (the Newport CC Boundary) and Ruskin Avenue, to help what water there is find its way to Fourteen Locks. If that is not possible, then vegetation should be cut back, and weed and high-spot dredging should be done. This could be done right now, as there is no water in the canal then silt high spots can be easily identified and removed with a long reach digger.

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