Beneath the waterline with Nicola

What got you into river snorkeling?

"I have long loved snorkeling – but usually on coral reefs, the Mediterranean or English south coast.  During the lockdown of 2020, travel to such places was not possible so I was missing the snorkeling.  Then during that hot summer, on the 31 July, we got a knock on the door from my sister in law, on her first outing since lockdown, from Norwich to London; she was stressed out because of traffic jams on the A11 and travelling in a car without air conditioning.  We gave her a cup of tea.  Then my daughters – who often go and swim up in the River Lark on Cavenham Heath, near where we live, said – come for a swim with us, Auntie Clare.  I came too, and on a whim, brought my snorkel and mask.  The underwater world I discovered – in a place where we have lived since 1995 – blew my mind – immediately, Brown Trout parr and a range of fish I’d never even heard of like Chub and Dace. That swim changed my life. 

Through Google I found the wonderful Imogen's River Swims | swims and swim places, and related issues (imogensriverswims.co.uk). By visiting the places she recommends and following her advice, I built my confidence so that the world of British Rivers is now my oyster."

Where is the best snorkelling on the Great Ouse and its tributaries?

"Personally my favourite river is the Wissey which has many good spots along its length. As does the Nar in its upper reaches. The Little Ouse is also lovely, for example where it goes through the forest downstream of Thetford.  And there are some great spots on The Lark, such as around Icklingham.  Burwell Lode can be like a fish packed aquarium, for example at Upware – but there are a lot of boats."

Where is less nice, e.g. do you spot signs of river habitat deterioration in your explorations?

"The worst visibility I have encountered is on the Cam downstream of Byron’s pool.  The last mile of Lee Brook before it joins the Lark, downstream of Freckenham, is a dead zone.  The Lark upstream of Bury St Edmunds is a bit grim. The Little Ouse upstream of Euston is disgusting, perhaps linked to the Gressingham poultry works. There are many more examples – for example in my own village, the strand of Tuddenham Mill Stream, tributary of the Lark, that rises near Tuddenham sewage works.

But the truth is, that there are no rivers in the catchment where one sees no signs of river deterioration. Very few, if any stretches, lack the algae and silt characteristic of eutrophication and run off. And even where such signs are not dominant, the rivers have been canalised, dredged or invaded by Signal Crayfish and other invasives.  Litter is also a bit of an issue and I often report illegal crayfish traps to the Environment Agency as there is a problem with the likes of otters getting trapped in them and drowning – the first one I found contained a pike that had clearly been killed by it" 

Are you worried about murky waters, like can you see anything and how do you avoid getting ill?

"Very worried. For snorkelling, the most important factor is water clarity so one is much more attuned to it than normal outdoor swimmers would be.   However, at least in the eastern Ouse catchment I think we are quite lucky compared to elsewhere in the country.  For example I have never actually encountered signs of raw sewage. And I have never got the slightest bit sick from snorkelling in them. Obviously I try not to drink the water, but take no steps, for example, to wipe my snorkel before putting it back in my mouth. The only avoidance measures I take are connected to swimmers itch, to which I am susceptible (the rest of my family do not get the itchy mosquito like lumps from when the flatworm parasite related to bilharzia buries into your flesh thinking you are a duck, then dies because you are not).  It is for this reason I tend to use a wetsuit or full body rash guard year round."

What is the most exciting thing you’ve seen underwater?

"I remember mind being blown by finding my first breeding congregation of Brook Lampreys. And the thrill of spending quality time with elvers in the Great Ouse at Brownshill Lock in Cambridgeshire– a very surreal experience as I was, at the same time, in the water with a lost mother and calf Common Dolphin. It is always special getting up close and personal with a big Brown Trout or Pike.

But besides fish there are all manner of things to discover in our rivers – hauls of jewellery, fossils, flint tools and clay pipes, even a sawn of shot gun and a human skull"

What kit do you need?

"Most important is a comfortable mask and snorkel – I have a prescription mask and snorkel by Tusa.

Fins and matching diving bootees (for walking to and from sites and through or round unswimmable bits of rivers) – I like the Scubapro ones.

I tend to use a 7.5 or 5.5 mm Subea hooded wetsuit from Decathlon to keep warm but also protect from glass on the river bed and overhanging brambles and nettles as well as swimmers itch. And/or a full body rash guard with foot and hand loops eg from Scubapro.

I wear diving gloves which are fingerless on thumb and index finger to allow photography.  This keeps hands warm in winter and protects them eg when using them for moving upstream – see below.  But when the water is below about 6 degrees tend to have to wear diving mits over them.

I wear Kevlar caving knee pads with fully adjustable Velcro straps to protect wetsuit and knees from glass etc.

I swear by my Olympus Tough camera – currently using the TG6 and have just bought the brand new TG7.  People also get good results with GoPros.

I always carry a diving torch – the best I’ve found is the OrcaTorch D710."

Do you snorkel all year around?

"Yes, the constraints are water visibility and the flow being too strong when the river is in spate. I tend only to snorkel when it is sunny otherwise photography is too tricky – sun sparkling on ice can be v pretty. However, in the colder months eg Dec-Feb, fish tend to disappear so there is less to see."

What do I need to know if I want to try?

"Start with Imogen’s website.

Access is a grey area. I work on the basis that if you get in the river from a road, footpath or other place with public access, it is OK to be in the river (in theory as long you don’t touch the riverbed!) but it is best to ask permission from landowner if in doubt.

For snorkeling you don’t need nearly as much water as for swimming – even 6 inches is fine – often the best snorkeling is essentially crawling along the river bed, walking with your hands, letting your body float behind, or if necessary, crawling on your knees.

I always snorkel up stream and then whoosh back down, but on the way down you don’t see so much, partly because you’ll have stirred up lots of sediment.

To get as close as possible to fish, move slowly, with quiet frog movement of your  fins rather than kicking up and down.  You often get closer to fish by approaching parallel rather than perpendicular to them.  Lifting up stones you often find interesting things underneath like Bullheads, Stone Loaches, leeches, freshwater shrimps. "

Imogen's River Swims: https://www.imogensriverswims.co.uk/

Nicola's Twitter/X feed: https://twitter.com/numenini