SIDE BY SIDE, my dive buddy and I enter the water at the top of the pool and drift slowly downstream, using our river-sticks to guide ourselves around rocks and other obstacles.
Once in the deeper water, the current levels out and we can begin to swim around and look at some of the local wildlife.
Small brown trout look rather confusedly at us and the odd crayfish makes its presence felt from beneath rocks. Eventually we make our way to the riverbank and get out. It’s been a brilliant dive.
Shivering on a riverbank on a cold November morning might not sound the most tempting of ideas, but river dives can be hugely rewarding.
I have been a diver for only four years, so I’m still fairly new to the game. For three of those four years I’ve lived in Cornwall, so have had all manner of dive sites from which to choose. However, some real gems that are often overlooked are the rivers.
The UK has 20 major rivers, and these spread out into a lot of brooks, babbles, creeks and canals, many of which can offer rewards for adventurous divers.

VISIBILITY WILL VARY depending on whether it has rained recently, or on the area of the country. The Rivers Lune and Duddon in the north of England,
for example, can have a peaty, almost sepia-like look to them, while southern chalk-streams are crystal-clear (though rarely deep enough to dive).
Crawling around a river bottom requires upper body strength. River-diving can place exceptional physical demands on a diver, so you need to be in good, if not superb, physical condition.
Divers should pace themselves and be aware of the stamina of the weakest person in any buddy team. Moving against current can be fatiguing and can rapidly deplete air supply. Divers may inadvertently place themselves in a position requiring heavy workloads.
Excellent cardiovascular conditioning and a reserve exercise tolerance is a requirement for swift-water diving.
If you can hear the river before you get out of the car, it’s running too fast to dive. Just like watching out for the tides when diving in the sea, rivers have lots of variables to consider before diving.
There are a few simple rules that will keep you safe in the water (see panel).
Rivers aren’t well suited to lots of divers in the water at once, so keep the number low for a more enjoyable dive, but don’t dive solo. Be sure to check that there are no anglers, too – the last thing you want is to be some fisherman’s “one that got away” story.
Try to find out whether there are any sewer drains going into the river, because the risk of picking up illnesses can be a lot higher than at other venues. Contacting local river authorities is always a good start.
As with keeping salt off your gear when at sea, it’s important to wash your equipment after river-diving. Bits of debris and small insects can find their way into your gear and cause problems later on.

THE WILDLIFE IS A BIG DRAW. Whereas in some inland dive sites the biodiversity may extend to no more than three fish species, our rivers can hold as many as 45!
As well as fish, species such as crayfish, water voles, swans and even otters become readily available to the river-diver. Wildlife is either surprisingly tame or darts off at the first sign of you – it depends how well dived the area is.
Larger river fish such as barbel, chub and pike are present in most of our rivers, though their smaller cousins such as minnows, bullheads and gudgeon are becoming a much rarer sight.
For the underwater photographer, rivers open up a whole new world, with subjects such as water birds, amphibians and freshwater fish all there for the taking, though it’s not quite as easy as photographing an urchin beneath Swanage Pier!
Much of my underwater photography has been conducted with camera traps or while snorkelling, as some of the very shallow rivers (2m or less) are not practical to dive. But the flow of water and constant movement provides a great chance to capture the essence of a river.
Buddies need to have a separated-diver plan. This is not a major problem while drift-diving with both of you on a line connected to a float, but in more intense currents, towing a float is both unsafe and impractical.
Where we most often dive, there is an erosion barrier breakwall along the entire length of the river. The current runs at 2-10 knots, and boat and fishing traffic is heavy, so a direct ascent to the surface would not be recommended.
In such currents, too, a diver off the riverbed, especially at the surface, can quickly be separated from a buddy.

THIS IS OUR PLAN. Before the dive, one diver is named “designated mover,” the other the “designated non-mover.”
When separated, both of us look around and then move towards the wall along the shore. On reaching this wall, the “non-mover” remains stationary for three minutes and then surfaces along the breakwall.
On the surface, the “non-mover” holds position along the corrugated steel wall with the help of a river-stick, and notes the location.
A river-stick is a 15cm spike used to help pull the diver upstream, to hold position to recover those valuable riverbed finds, and to control velocity during the drift downstream.
There is no need to buy a purpose-made river-stick – any piece of metal with a sharp end, such as a fishing-rod rest, will work.
The “mover” (usually the most experienced river-diver) goes to the wall, moves upstream for two minutes, heads downstream for one minute and then surfaces.
On surfacing, the divers wait 10 minutes and then, if no contact is established, call for rescue assistance.
As the divers have surfaced along the wall, the last known point can be reasonably established, should a search ever be necessary.
This plan is not universal, but experienced river-divers diving near shore in intense currents with a restrictive barrier along the shore use it.

CHOOSING THE RIGHT time of year is important. In summer rivers are much warmer and more comfortable to dive, but contain a lot more vegetation. Algal blooms and abundant pondweed can reduce visibility and entangle you.
Winter offers by far the best clarity (if the rain holds off for a few weeks) but requires a drysuit.
Spring is best for wildlife, as the river is starting to warm up, the fish become more active and frogs begin to spawn.
The essence of all diving is to move in harmony with the environment. In confrontations between Mother Nature and humans, the latter will lose, so go with the flow but under control.
Fins should not have large openings, as such holes can allow you to be impaled by objects on the riverbed.
This has resulted in divers losing fins and, in a worst-case scenario, could pin them on the bottom.
The cardinal rule is to “keep your fins lower than your arse”. When moving in intense current near a riverbed, spread your legs spider-style and drag your fins along the bottom.
If your fins get higher than your buttocks, you’re more likely to lose control and tumble. If you find your
legs rising, kick hard and drive downwards at a slight angle.
Once velocity is established, raise your head and allow your legs to drop below your buttocks. The preferred orientation is moving headfirst or sideways down the river. By moving sideways, the silt from your dragging fins will not cloud your visibility.
Moving sideways allows two divers to stay together by moving downstream facing each other.
In some areas, particularly over a clay bottom, vis can deteriorate rapidly.
If this occurs, stop and allow the clay cloud to move past you before resuming downstream progress.

THE REAL KEY TO CONTROL, however, is the use of a river-stick, and the basic technique known as “stick and glide.”
As the current keeps you moving downstream, so the stick is used almost continually, impaled into the bottom to act as a brake and to control velocity and orientation.
The idea is not to stop, unless you wish to pick something up, but to move down the river under control. The spare hand is moved along the bottom to help hold position.The cycle is repeated as you move downstream, allowing buddy contact to be maintained in low visibility.
If one diver finds something worth recovering, the stick holds position. As the divers are facing each other, when one stops, the other is aware of the halt and either waits or assists with a recovery.
Having said that, a common separation point comes when one diver stops to recover an object and the other fails to notice and continues drifting out of sight.
The stick also allows a diver, albeit with physical exertion, to move upstream. It is extended ahead either to hook an object such as a large rock, tree branch, or debris on the bottom or, if the bottom allows, to drive the stick into it.
This “reach-and-pull” approach can also be used with a technique we call “the inchworm”. This involves anchoring the river-stick before lifting the back into an arched position.
The current moving over an arched back helps to hold the diver on the river bottom. The arm holding the stick is then extended, and the cycle repeated.
This successive reach and collapse (like the movement of an inchworm) is physically demanding, and used primarily for short excursions in moderate current. In some cases, this technique can be used without a stick.

ONE SPECIAL THRILL of intense (up to 4 knots) current diving is to “fly” 2-3m off the bottom and let the current hurl you downstream.
As long as the vis gives you time to avoid objects, this is an exceptionally challenging and invigorating activity.
The unforgiving nature of extreme current flow has cost many divers their lives. River-diving is one speciality area that definitely requires techniques and equipment distinct from typical open-water recreational training.

* Follow Environment Agency (EA) officer instructions.
* Have licensed boat-cover.
* Have fully equipped shore-cover at all times.
* Display an A-flag at all times.
* Post a look-out to warn approaching boats.
* Never dive within 50m of a lock or bridge.
* Never obstruct craft.
* Archaeological finds must be sent to the EA.
* Confirm dive with the EA the day before.

* Birks Bridge, River Duddon, Cumbria
* Devil’s Bridge, River Lune, Cumbria
* River Orchy, Argyll
* Stainforth, River Ribble, Yorkshire
* Lower tidal, River Trent, Yorkshire