EBB AND FLOW
The CRT outlines its strategy to deal with the challenge of water shortages
IT seems rather perverse to be writing an article about canals running short of water when it’s the middle of winter, the rain is lashing down outside, and a stream of Canal & River Trust alerts are coming in, warning of rivers all over the network going into flood conditions. But until a couple of weeks ago there were serious concerns about canal water stocks, not just for the immediate future (with part of the Grand Union Leicester Section still indefinitely closed after four months), but for the forthcoming year – and CRT was making contingency plans to make the most of what stocks it had.
Of course, Sod’s Law says that whenever you plan an article about water shortages, by the time you’ve finished writing it there will be floods. And sure enough, as we go to press the Leicester stoppage looks set to come off, reservoir levels almost everywhere are looking healthy, and it’s easy to start wondering what all the fuss was about. But it’s not like the recent weather has been spectacularly wetter than the autumn (unlike, say, the Boxing Day 2015 floods that hit the North of England) - so what happened?
CRT’s Head of Water Resources Adam Comerford explains that it’s all about groundwater. As he describes it, the ground is like a giant sponge: a dry winter and spring last year left it very dry to start with; when the autumn rainfall arrived, it tended to just soak into the ground and gradually fill up its capacity, rather than running off into the streams which feed the reservoirs.
But finally, right at the end of 2017, the ‘sponge’ filled up, it couldn’t hold any more water, and the rainfall and melting snow around Christmas and New Year went straight into the streams. In Adam’s words it was much more “effective” rain in terms of filling up the reservoirs. He quotes some figures to show just how dramatic a change it was.
Saddington, the main reservoir supplying the north end of the Leicester Line, went up from a worryingly low (for the time of year) 52 percent full to a healthy 87 percent in just one week – to put it in context, that’s something like an extra 600 lockfuls, and there were similar improvements at Welford and Sulby reservoirs.
That’s just one of several areas which had given cause for concern. The other restriction (due in part to pump problems as well as lack of water) was the Grand Union’s Tring Summit. Here, to complicate matters slightly further, the Marsworth reservoirs are largely fed directly by groundwater (think of it as water oozing out of the saturated ‘sponge’) so it’s less predictable when they will start to fill up. But here, too, the situation is suddenly looking a lot better – and for the longer term, CRT is looking to improve pump reliability.
The other main area of concern is the Birmingham Canal Navigations and connected canals. This traditionally is well-supplied with water, but has been hit by a combination of circumstances: • Upper Bittell Reservoir levels were
drawn down for safety work • Rotton Park hadn’t refilled well during 2016-17 and was running very low • At Earlswood there was work to be done on valves, further complicated by a need to remove invasive non-native fish species • Chasewater (owned by the local authority for historic reasons) had issues with the draw-off valve, leading to lengthy discussions between CRT and the owners over what work was needed and who should pay.
However after three weeks of wet weather, plus an agreement to operate Chasewater in the spring, Adam would now be ‘disappointed if we run short’.
The Kennet & Avon also has pumping problems – and on a canal with very restricted storage capacity, it only takes one of the series of six pumping stations from Bradford-on-Avon to the summit to fail for there to be serious problems. CRT is working on upgrading the pumping systems for the next 20 to 30 years.
Finally the Chesterfield and the Lee & Stort (where the Environment Agency had been concerned about low river levels) are recovering well.
But what if the ‘effective rain’ hadn’t arrived when it did? CRT was busy drawing up contingency plans for emergency pumping, and bringing forward planned feeder clearance and lock gate relining work.
At the same time, if thought had needed to be given to bringing in restrictions this year, then the approach now would be ‘gentler, softer, sooner’ – and making early contact particularly with the holiday hireboat operators. This follows some lessons which have had to be learned
following previous droughts in 2011 and earlier, when more restrictions were brought in abruptly, or announced in an unhelpfully doom-laden way. As regards the actual restrictions, computer models can give a range of possibilities and probabilities, Adam says, but at the end of the day it’s a judgement call.
On the subject of droughts, CRT is now working to a target that waterways should be able to cope with a ‘once in 20 years’ level of water shortage without major closures (with the Leicester Line bordering onto that level of drought). A major part of its five-year water resources project is looking at how to meet that target, which canals (such as the Rochdale) are failing to meet it, and what threats to water supplies are likely to increase the chance of missing the target in the future.
And one of the threats is the Water Framework Directive, which is driving a requirement for all ‘abstractions’ (even feeds to canals which have been in place since the canals were built) to be licensed by the Environment Agency. CRT has two years to apply for probably 250-300 licences (it’s not entirely clear exactly what the EA will class as an abstraction), then the Agency has three years to decide whether to grant them in full, to refuse them, or to grant them subject to conditions (such as a minimum river flow below which no water may be taken). And although this is an EU directive, it’s already been enshrined in UK law since 2003, its origins are seen as going back to the droughts of the 1990s and the lack of control over abstractions, and there seems little chance that Brexit will bring about its demise.
Another issue has been the proliferation of marinas in some areas – and for several years now, applications for new marinas have been conditional an analysis of whether there are adequate water supplies. CRT hasn’t turned any down on water grounds yet, but in some cases has “pushed them to look at mitigation” – for example local backpumping schemes, and has “come close to saying ‘no’ or imposing conditions”.
Those are the threats to supplies: what are the plans to deal with them? The study includes taking a look at a very traditional way of saving water – the side pond. These economiser chambers built alongside locks were once a common feature on canals where supplies often ran short, but generally went out of use some decades ago – and CRT (and its predecessor British Waterways) has tended to look at back- pumping instead of reinstating what they felt was a system unlikely to be understood by many boaters. But now, CRT will at least look at where they still exist, where they could be put back into use, and whether it would help – for example those on the Coventry would probably be little help, as the water feeds down to other canals which need its supplies.
But backpumping and new river feeds are likely to be the main way forward. Adam is very aware that when he “bangs the drum for water schemes” he’s competing for limited funds against other demands on finance whose usefulness won’t just be limited to once every few years. “It’s not like a broken bridge or a damaged embankment,” as he puts it.
But subject to this, his team are working on designs on and feasibility studies for some major schemes in the coming years – with the Rochdale and the Leeds & Liverpool among the front-runners.
Even as I’ve been writing this, the announcement has come in that the Leicester Line is reopening. Yes, it’s a further good sign that the worst is over for now - but the fact that it’s been closed until mid-January is an indication that there are issues to be faced in the longer term.
Rochdale Canal: candidate for backpumping?
Could these old side ponds at Marsworth have helped?