The Uk's Unique 1mm Square - Map Mystery 

Good fun, but in chalk country the concept of a watershed is somewhat moot. Most rainfall will soak into the chalk before it even reaches a stream, and contributes to an underground aquifer which feeds springs like the one mentioned in the video. The upper surface of the aquifer doesn't necessarily follow exactly the profile of the land surface above.

Now you need to map the underground aquifers and get really complicated.

As a reenactor I can assure you that when it rains on Roundway Down it simply soaks into all your kit and at the end of the weekend ends up in Yorkshire or Cardiff or Portsmouth or Devon or...:-) Loved the video and nice dog, what's his or her name?

Paul and Rebecca, I absolutely love your videos. Thank you so much for taking all the trouble and care you do in preparing them.

It was great fun watching this. Apart from the interesting premise I loved the little jokes, visual and otherwise, you sprinkled in there. Also, I appreciate the huge amount of work and preparation that must have gone into this little project. It must have been fun planning it all. Well done, keep up the good work.

Fascinating theeory, in a fascinating area. I come from Marlborough, my grandfather was born in Etchilhampton and previously the family cames from around Devizes, Potterne and Melksham. My great-uncle drove the pumping engine at Crofton, and my birth was within a couple of hundred metres from the river Kennet. So, I claim this as personal turf. As someone who does flood resilience planning I have often undertaken similar exercises to that whichyou have done on this video, and it is good stuff. However, it is only dealing with the run-off, the direction of travel of the surface flows. It would also be useful to understand the geology and the hydrogeological landscape, because a great deal of this water will percolate and will travel undergound - the underlying geology may very often be confusing when relating it to the topography. Any declination or bending of laid down sedimentary layers can mean that whereas on the surface a run-off potential is leading south, leaving a hill's summit behind it, the underlying inclined layers may actually turn percolating water to head in an entirely different direction, even north under the summit and out be through a spring heading in the opposite or entiely different direction. Given the compaction of soil (what there is of it on the chalk downs!) by the action of sheep, it is likely that most water will be distributed by running off, but there will be oddities that will throw the calculations out. As map lovers, I heartily recommend to you the online resources of the British Geological Survey (BGS). The limited numbers of hydrogeological maps are both fascinationg and very pretty!

There is another triple point between North Sea, Bristol Channel and Irish Sea, looks to be close NW of Baldwin's Gate on A53 SW of Stoke. Lived for a while looking over one of the low points of the Pennine watershed. The lowest point on that watershed is used by the Leeds Liverpool Canal, but curiously this is not a cutting or tunnel but an aqueduct.

Living near the continental divide for the U.S. (Idaho Montana border), this video really hit home. There are three triple points fairly nearby (by U.S scale) - Snow Dome, British Columbia (flows to Pacific ocean, Arctic ocean, and Hudson bay) - Triple divide Peak, Montana (flows to Pacific ocean, Hudson Bay, and the Atlantic) - Three waters mountain, Wyoming (drains to Pacific Ocean, Atlantic Ocean, and the Gulf of California)

there's a couple more triple points in the UK. Rivers Clyde, Tweed and Annan, flowing into the Clyde estuary, the Irish Sea and North Sea respectively. Ben Lui in the highlands has a watershed to the Clyde (via Loch Lomond), Atlantic (via Loch Awe) and North Sea (via the River Forth)

Years ago I had to do a similar survey of an area of about 50 Sq Km. It looked pretty daunting until I converted it to Sq Miles and then only had to deal with a bit over 19 of them which was way more manageable.

Thanks very much, another entertaining and informative video. I’m a Devizes resident and I’ve never felt more proud of Roundway hill! We’ve always known it’s a lovely place to go I’d not realised it was so unique…

As both a Wiltshire resident, and drainage engineer... this was amazing! Well done to you both...

Especially loving this video, as I know all these places well from the Marlborough Down Challenge running event!

These videos are one of my happy places! 1:35 the face has me rolling with laughter! Needle in the haystack moment.

You two are just great! This is genius, I absolutely love it, finding the precise spot of a three way watershed!! Keep doing what you do, the world needs people with curious minds like yours. Your vids are always interesting, they make me realise how much there is out there that is simply fascinating, and that this country has so many layers of intrigue. It's sometimes hard to love Britain, but you two remind me that we are lucky to live here, it's all out there!

Brilliant video. You’re doing something with the maps I never thought of, and now want to… if I had the time. Thank you for finding something else really interesting & new!

Nice video - and yet again I've learnt something! Thank You for coming up with these gems!

Brilliant video. Love your persistence in finding this unique spot!

Loved that thanks. Actually love all your videos.

there's a spot in Pennsylvania that is similar: the head waters of the Allegheny which flows into the Gulf of Mexico, the Susquehanna which flows into the Chesapeake Bay and the Genesee which flows into the Great Lakes are within a very small area northeast of Coudersport, PA.

Really loved that thanks. What a lovely place that was. How good are you finding that spot.. thanks for taking me along. Please stay safe and take care

You’re taking an analytical approach. I think I’d try an empirical approach - drop a bit of peppermint scented water at your proposed equi-shedding point and see (well sniff) which river it turns up in. That’s what plumbers do when they want to check for a leaky sewer!

Great scenery. Very interesting video. Many thanks.

Fair play really enjoyed this! Thanks for your efforts ✌️❤️

Great video, & interesting topic, well presented with humour, thank you! 🙏

Absolutely amazing. Hats off to you both

I can tell you're getting more creative and ambitious with your editing structure. Fantastic to see! Very fresh!

Very interesting research! Right length, lovely photography! Thank you!

What a great video. Thank you for making

Haha, fantastic! I absolutely love your railway videos, but this one was wonderful in that it brought up all sorts of memories of A-level geography and going out doing field work (followed by liquid refreshment at the local hostelry!) 🤓 Fascinating that one point could be the watershed to distribute into three three distinct geographically separate waterways. And I love the hands on nature of the work…and especially the crafted Blue Peter sticky tape type map and pen drawn water vectors. It was like a throwback to the wonderful Open University programmes on geography and geology I used to love watching 😎 Yes, I did used to watch these things as a child. I was considered a bit odd 🙄 Cheers guys, great fun as ever 💚👍🍻

Loving the humour in this and previous videos always enlicits a smie from me :) lovely doggo!

The best way to start the day. Cup of coffee with Paul and Rebecca (and the dog) of on their travels with her another fantastic story that has clearly been well researched. Love it you guys!! 😍

Very thought provoking, well done and thanks you three

Great little video, I enjoyed it a lot.

Hey you're in my neck of the woods 😊..... I'll have to check out that beautiful spring. Reminds me of Luccombe Springs that I visited recently and didn't know about until reading 'Hidden Wiltshire' blog.

I love watching your videos so interesting.

Great fun video. excellent mapping exercise. loved it!

It's always surprised me that the Wansdyke is so little known as it's huge and a natural walking route with great views along a ridge line. I used to walk it frequently as part of a long circular route starting at Avebury, then to the Ridgeway and then south to where it crosses the Wansdyke. From their, west along the Wandsdyke, crossing the A361 to Morgan's Hill, which is where Wikipedia believes is the hydrological triple divide where rainfall drains into the English Channel, Severn Estuary and the North Sea. That's about 6km from Roundway hill... From Morgan's Hill I would go via the Old Roman road to Cherhill Hill and the Landsdowne Monument, and then back to Avebury by way of Beckhampton. A great walk, full of ancient mysteries but maybe a bit long for some.

Brilliant video and interesting as always :)

OMG amazing video awesome you guys really help me when I down. Thanks

Very interesting, thank you. Beautiful countryside with so much history.

You know, I enjoy all your videos, but this may be the best one you've done yet!

To see all this joy, enthusiasm, effort, dedication and effort about …? You two are absolutely delightful.

We did a similar thing during lockdown (on paper!) when we noticed that the Severn, Thames, Nene and Great Ouse watersheds almost meet at a "square" point. They meet at two triangle corners, of course, but they are super close.

omg i love your funny starts lmao , hello again paul and rebecca , thank you for another very interesting video, looks like the dog had a great time lol , well done guys 😊

I'm sure there will be a point somewhere around Crewe where your split raindrop could finish up in the Severn, Trent and Mersey, so ending up in the Celtic Sea, North Sea or Irish Sea.

Thanks great fun to watch. As a bonus learned something new too. Well done

One of your most entertaining videos to date, excellent work

Fascinating and very entertaining. Enjoyed that. Beautiful dog. Thank you.

Great vid! Looks so much fun too :)

just stumbled across your channel from the youtube gods algorithm. i love geography and the uk ( i am from the peak district) just having a binge watch of your videos and subscribed. keep up the ace videos. great production quality and you have a natural ability infront of camera

I love this part of the world. Thanks for the interesting video.

Amazing work team 👏

Brilliant guys!! I live in the shadow of Roundway Hill and although the countryside is spectacular I had know idea it was unique. Thanks for posting!!

I love a map mystery, thank you very much. I live on a watershed where the rain on one side takes about an hour to reach the sea and on the other it takes days.

Hello Paul and Rebecca. I really enjoyed this vid, as we live on a watershed (Avon-Nene in Northamptonshire) and I love the idea that puddles on one side of the road end up in the North Sea, and on the other, the Bristol Channel. You might want to check out the land between Staverton and Charwelton (also in Northamptonshire), where rivers rise flowing west (Leam (Avon/Severn)), south (Cherwell/Thames) and east (Nene). Not quite as good as yours, because both the Thames and the Nene flow into the North Sea, but pretty good 🙂

Great story again with some great editing.

Liked, subscribed and commented. I'm a new watcher and living the channel.

Hi from Texas. Great video, a very interesting subject you've presented here.

a interesting piece of research. and good to see Rebecca out and about again

Your bookcase at the beginning of the video is amazing!

Great editing Rebecca!

Y'all clearly have a lot of fun with these videos. :D

Hi Paul & Rebecca , as you say love a good map mystery , great vid , cheers Tim, from Taunton

So is this the UK equivalent of a Continental Divide? Good detective work as always...

Very nice locations, need to visit.

Great to see your dog sniffing out the Wiltshire triangle with you. I think we all want to know his name!! Very well presented as always very enjoyable. Good luck from Spain!!

I got a bit lost. Is 'Sheer Drop' anywhere near 'Sheerness'? Fascinating and entertaining article. Well done you two

brilliant video keep up the awesome work

This was mainly filmed in what I regard as my backyard and am so impressed with the amount of research you do!

Thank you for a very interesting video. There is also an unusual watershed on Seat Sandal in Cumbria where rain flows to one of three places from the Solway to Morecambe Bay.

Lots of fun, this video, thanks!

From Bromham, can see the woods from the back window. I know where I'm taking the kids this weekend. Thanks for an amazing video and for hopefully helping get the kids excited about the landscape they live in.

Brilliant!! as ever. Thanks

Thanks for sharing.

Unique like this channel. Another great video.

Great video with fun editing and a "suspense build-up" 👍👍 Interesting investigation adventure with Bourbon 👌🐕

down to a mm well both of you what a treat for sunday thanks

You guys are great, love the history and locations. Melbourne, Australia

You could have looked for the Dew Pond on the top of Roundway Hill :)

Oh we loved this one - fantastic viewing before Sunday dinner.

Back in my home territory. I love Wiltshire and are often traversing the Swindon - Devizes route though Avebury

It does not matter who’s who here you are a right pair,you both exist as one by the look of it in tandem,you complete each other, nice to see.

Marvellous P&R. Great editing as well

Geology made exciting. Very well done!

This was so good 👍 so interesting thanks good blogging 😊

What a cracking vid! As a map lover (cartophil???/geo geek??) that was right up my street! Subscribed!

Makes you think? Great video!👏👏👏👏

Ahh you came up as suggested as I watched the Rudgwick stuff yonks ago…..Subbed🙌😅

Great work. Great Vid.

great fun video, most enjoyable.

Fine looking dog . As always interesting content an beautiful scenery .

One of my best friends' family owns much of the land from there up across to Swindon so I've spent decades of my youth causing havoc in those parts. I have a vague memory of someone mentioning something about 3-points but evidently it didn't register at the time so your video is most welcome.

Reminds me of 9 Standards Rig on the Coast to Coast - the point where a drop of rain lands and either ends up in the Irish Sea or the North Sea. Great video! :-)

Youve visit my old neck of the woods as they say. The spring head you visited tastes wonderful clean,fresh and free.

What I found most entertaining besides watching the dog enjoying its walk was the great and varied expressions on Rebecca's face, it appeared that she was thoroughly enjoying herself!

Thanks very enjoyable!

Next week a shrunken Paul, Rebecca and friend following a split drop by another friend! That was a great vlog and amazing how you come up with ideas for your vlogs.

Good detective work!

You are not the only one I some times go out to see some thing and forget some thing. The last time I forgot my watch so I didn't know what the time is.