Running out of water

When I was riding a bike on the Stratford-upon-Avon Canal last year, I came upon a narrowboat sitting in a lock, facing “upstream,” with the upper gate open. The owner of the boat was chatting amiably with a gongoozler and it seemed they had not a care in the world. I stopped to take pictures, thinking I had just a moment before the boat would continue on its way, but after a while it dawned on me what I was seeing. The boat had run out of water.

For those of us who imagine England to be a rain-soaked country, it’s hard to imagine ever running out of water. Of course water supply problems have plagued canals from the very beginning. James Brindley had to literally prove to Parliament that his scheme to build the first true canal would hold water, demonstrating that lining a canal bed with puddled clay would keep the water from simply draining away. Any examination of a canal also reveals a network of pumping stations and reservoirs to supply the canal with water and it’s no coincidence that canals often run alongside rivers. Rivers were a source of water for those canals and also created the gradient that made the canals possible.

One would think, however, that modern-day canals should have a reliable source of water. After all, electrically operated pumps have replaced water- and steam power-driven pumps, but unfortunately the inherent inefficiencies (leaking gates, canal breaches and vandalism) of the canal network and the effects of climate change (both drought and flooding) mean the water supply is anything but assured.

Ignoring systemic and long-term problems, however, what was plaguing this particular narrowboat on one of the Wilmcote flight of locks on the South Stratford Canal? There simply wasn’t enough water to float the boat over the cill of the top gate. The cill, of course, is the brick or concrete structure against which the gate(s) close. Boaters are warned to beware the cill, lest the rear of the boat be caught while locking down (going to lower water). In this case, however, the boat was locking up, but the water level in the lock chamber hadn’t been sufficiently raised by the water in the upstream pound—the length of water between this lock and the next, higher lock.

There can be insufficient water in the pound for any number of reasons. Water to a canal is provided at the highest point(s) of the canal—water, after all, flows downhill. On a busy stretch of canal with many boaters navigating through closely spaced locks, pounds can quickly be drained. Remember, it doesn’t matter if boats are going up or down. Every time a boat goes through a lock, the canal loses water.

Many locks are equipped with a diversion channel that routes water around the lock, even when the locks gates are shut. This serves two purposes: First, if the canal has too much water (too much rain, leaking gates or vandals leaving lock paddles open), a pound can overflow the top gate of a lock or even flood the towpath. A diversion channel can prevent this. Second, a diversion channel helps ensure that the next pound has enough water.

What to do

So, what to do if you find yourself in this situation—unable to get your boat over the cill because the pound is too low. If the next higher lock is within walking distance, you’ll need to release water from that lock into the pound that’s too shallow for your purposes. Hopefully the next higher lock already has a full chamber, because then you can simply open the downhill paddles. If the lock chamber is empty, you’ll need to first open the top paddles, fill the chamber, close the top paddles, open the bottom paddles and then close the bottom paddles once the pound has been raised sufficiently.

If there’s a lockkeeper nearby, however, first inform him or her of your problem. The lockkeeper could very well walk to the next lock and release water for you, or advise against this tactic for whatever reason.

If the next lock is too far away for you to walk, your options are pretty limited. The most obvious solution is to lighten your boat by having everyone step out. You may even have to abandon the tiller and tow the boat out with the bow line. If that’s not enough, you can start removing luggage.

Out of luck

Unfortunately sometimes a pound can run bone dry, probably because of a catastrophic breach somewhere upstream. On March 16, 2018, an embankment failure caused a breach on the Middlewich Branch of the Shropshire Union Canal (it connects the Shroppie with the Trent & Mersey Canal). About twenty boats were left stranded in the canal. And in May 2017, vandals opened gates and paddles on the Worcester & Birmingham Canal, draining the canal between the Tolladine and Offerton locks.

Sadly if you find yourself in these situations, there’s little more you can do than call the local canal authority office and report the problem. Well, that and put the kettle on.

UPDATE: The Canal & River Trust has found the reason for the Middlewich collapse. Someone left the paddles open at locks above the collapse. Now it’s quite possible someone forgot to close one set of paddles. You’re supposed to close all paddles and gates after turning a lock, but apparently all the paddles on several nearby locks were left open. This sends waters down until it reaches a lock that’s been properly closed. Unfortunately the water in that pound then starts to overflow and if there’s an embankment, starts to undermine the bank. So this was probably vandalism.