There are 24 pure NH courses, and 18 dual purpose ones, or, 42 staging jumps meetings. Some, like Lingfield, staging very few! If there are 16 with water jumps, that's about 38%, enough, I'd have thought, for trainers to encourage their horses over them at home, since the chances of finding races which wouldn't include them now and then would be unusual.
Right, to your desire for water fatality stats, Colin: assume that the 16 courses with water jumps hold a typical average of 22 meetings each per season. That's 16 x 22 = 352 meetings. At a typical NH meeting, the card breaks down into 3 hurdles, 3 chases, 1 NH Flat. So, 352 meetings x 3 chases per meeting = 1,056. Now, assume you have an average entry of (let's be modest) 10 horses per chase. We have to do that, because each horse faces the water as an individual, taking an individual chance. So, that's 1,056 chases with 10 horses averagely contesting them = 10,560 jumps over the water. However, the water is usually jumped twice, so that's actually 21,120 times in an NH season that water jumps are jumped.
As I said, I witnessed only one direct fatality at a water last year - annoyingly, I haven't noted which course it happened at. He was quite well-known, though, and very capable. He just caught his hind feet in the water on landing, skidded, and sprawled. I'm not saying that there might not have been another fatality during the year at a water, but if there was, I didn't know about it. So one horse died out of 21,119 otherwise perfectly safe jumps - that's not a bad statistic, is it?
The BHA is working on pulling stats together (I understand from another forum that Di Arbuthnot is part of the working party on it) on the reason for in-racing fatalities, and seeking ways to lessen them. There are, as we all know, certain jumps which are designed to represent more of a challenge to runners than others. They're on downhill runs, they come in rows, or they come at the top of an uphill climb. There's no doubt that more of the horses killed at Fontwell, are killed as a result of tanking the back straight chase or hurdles obstacles and overpitching, for example. They may well fall over the last, as well, but by then it's often as the result of tiredness, losing concentration as they see the crowds or the side gate to the stables, and so on.
There's a lot more to the fatalities than just falling - there's the context of the fall, for example. You may have a faller who survives but who BD another, breaking its leg. You have SU's on turns which result in deaths in Bumpers. The worst killers are what are called rotational falls, where horses fall directly onto the front of their heads, usually breaking their necks just behind the ears, as all of their body weight is transferred rapidly onto that fragile area. (Viz MEL IN BLUE in the Foxhunters' Chase at Cheltenham.) These are the result of a specific way of colliding with the jump - the horse takes off too low to clear the top, hits it above the knee with usually his forearms or lower chest, which propels the arc of his body upwards, the head landing first. You do sometimes see this approach when a horse has overjumped the previous obstacle, and is either trying to compensate for that by lowering his trajectory, or has been slowed into the jump by the jockey, who doesn't want another ballooned leap.
There are a lot of fatalities over hurdles which are quite clearly down to sloppy preparation. Again, I'd go back to the French model. The horses are schooled from their first day of proper riding over little obstacles like poles, getting used to using their bodies for jumping. By the time they're only 3, they're already experienced with the stuffed-brush French hurdle. They're used to being ridden in the style which jumps jockeys, not Flat jockeys, adopt. What are too many of our nascent hurdlers doing? Being rushed through a quick few weeks over hurdles at their yards, having not done much, if anything, on the Flat. They haven't even got used to being ridden in a different way to the way they were asked to move for Flat races, hence we see so much rank behaviour. Horses are invited to pull against the bit for Flat racing - but you don't want an animal with its head in the air, fighting for the bit because it can't understand why it's being restrained, in hurdling. Again and again, we see appalling examples of what are all but blind bolters tanking for the first, heads in the air, the jockey sitting as tight on the rein as he can, and the horse not settling until sheer exhaustion begins to set in. That isn't hurdling - that's just rushing madly over obstacles! No wonder there are so many crashes through the wings, ROs, and PUs of horses exhausted by over-exerting themselves with bad behaviour. The French hurdlers, you'll have noticed, don't come over here and bolt off as if the Hounds of Hell are on their tail - they're tractable, they can be placed where the jockey wants them to go, they take willingly to any restraint, and they jump fluently. That's because they've been treated, like greyhounds, from their earliest days to do the job they're bred to do - not switched within weeks from one very different code to another, without proper re-training. You might as well have chucked your Flat horse over a few showjumps at home and expected him to go into the show-ring perfectly behaved, for all the help some British horses get before appearing in an entirely new career. Hurdling is treated by some as if it's just flat racing with a few things in the way, and there are hundreds of examples every week of just how flawed - and sometimes fatal - this thinking is. The BHA could, of course, mandate against the potential for crashing falls and other errant behaviour in hurdlers by requiring all Flat racers to be checked out for their skills at home by a monitor, prior to being accepted into NH racing. Because we know that the next step is, if they're not that good at hurdles - why, bung 'em into a Beginners' Chase! Aaaaghhh!
I leave it up to you to play with the stats for hurdles and Bumpers! However, the 270 horses in training which departed last year include accidents on the gallops, colic, in the stalls, as a result of overstrikes (injuries to tendons), slips on turns, BDs, heart attacks, as well as falls over jumps and hurdles. As far as water jumping's involved, though, it really doesn't contribute to a point of concern as much as bad standards in preparation, and forcing very tired horses over the last couple of jumps should.