Sunday, May 1, 2011

A visit to the bund (Wicken Fen not Shanghai)

Saturday, 30th April: All these Bank Holidays  make it difficult to work out what day it is, at least for me anyway. Saturday felt like Sunday – but at least it was sunny, although it was also a little bit windy as well. I did remember to remove the polarising filter on my lens, since it seemed to increase vignetting whilst not doing a lot of polarising. I decided to cycle one of my regular “routes” and one which has lots of opportunities for variations. (From Horningsea to Wicken Fen and back.)

Last time I had bumped into MikeC he mentioned the work taking place on what the Wicken Fen Lodes Way map refers to as Burwell Fen but appears as Adventurers’ Fen on the OS map. The NT also publish a Wicken Fen cycling map which shows Adventurers’ Fen between Harrison’s Drove and Burwell Lode  and Burwell Fen in the triangle made by Reach Lode, Burwell Lode and Lodes Way. I guess this is all an example of how place names can mutate and change depending upon interpretations of maps and where names are placed. For now I will stick with the naming used on the Lode Way Leaflet and call it Burwell Fen (although it feels wrong somehow).

Anyway back to the Fen in question – according to the NT leaflet it is one of the lowest parts of the Cambridgeshire Fens  (almost 2m below sea level) and a low level clay bund is being constructed to allow the fen to become a wet grassland habitat. The Swaffham Crier has a little more information including the note that the Lodes Way forms the eastern part of the bund and that it encloses 80 hectares of fen (just under 200 acres in old money!) and will facilitate shallow, seasonal inundation.

So I thought I would check out the bund work before it is finished and disappears under vegetation. I know I also said no more yellow pictures – but there are a lot of yellow fields about. When I had a look at my pictures I also noticed small blobs appearing on the pictures after Photomatix combination of multiple exposures. Only certain blues seem to bring it out I am hoping it is either a bit of dust on the lens that can easily be cleaned rather than dust on the image sensor within the bowels of the camera. I have tried the in-built sensor cleaning and pixel refresh as well.

Now this really is back to the ride; I headed out of Cambridge on Wadloes Path and then along High Ditch Road and then over the A14 along Low Fen Drove Way (which just after the A14 bridge is called Lower Fen Drove Way and then back to its original name further along. Although you can’t see much of a hill Honey Hill is just behind the trees in the middle of the picture.

There are suggestions that the Sewage Treatment works for Cambridge which is currently between Cowley Road and the A14 should be relocated to the Honey Hill area.  I used to work in the Science park area a few years ago and despite what people may say the Sewage works can generate some unpleasant smells. (Or something else is generating the same smells, which is unlikely.) This got a lot of local villages up in arms (dated 14 Nov 2006) but I am not sure quite how recent the information is and what the resultant decision was (if any). Why are so many documents published on the web, undated?

It seems to me that by re-locating the Sewage plant it would effectively be releasing valuable development land but under the subterfuge of eating into Green Belt Land.

This is the same field but looking along Low Fen Drove Way towards the North.

The tracks around here are solid mud, fortunately (for cyclists) the mud set before too many ruts have been carved out. You still have to pay attention, it is not pleasant when cycle wheels skip about.  What’s that another yellow field at the end of the path?

Whilst still on Low fen Drove Way, after crossing the disused railway line, but before crossing the Burwell leg of Pylons it struck me just how much may blossom there is around it seems to have been out a while and there are white bushes all over the place.

This is the field at the end of that track in the previous picture. (plus 1). Those are the pylons marching off to Burwell.

AI then carried on to the Horningsea Road up to Horningsea and then along the Harcamlow Way to Lode. I took the Upware Road up to Upware and then towards Wicken. As I was cycling along Great Drove I took this picture of the neat rows in the field looking towards Reach Lode. The building off to the left, next to the haystack also features in the pictures taken here, it is the ninth one down.  According to the 1930 OS map it is Blinkers Hill.

Past Upware there was a field with Linseed just coming into flower. I will have to keep an eye on that as it develops.

At the moment the flowers are just small discs of pale-blue dotting the green.

Whilst the tracks are so dry I have taken to using Docking’s Lane to avoid cycling along the A1123 to Wicken. I don’t mind the road that much, but the track to Lower Drove (and the NCN11 between Ely and Wicken) is much nicer. You get to cycle along fields of green and yellow, “fenced in” by cow parsley.

After negotiating Wicken Fen, I have come to the conclusion I must be a little paranoid – what a cyclist thinking every one else is out to get them surely not I hear you cry! However negotiating through Wicken Fen on a busy day starts with cycling down the road past the CAR PARK. It seems to me that many people drive out to the countryside for the peaceful enjoyment of nature, a way of getting away from motor-traffic. Yet once back in their cars some of them don’t seem to show much courtesy to the cyclists also wishing to do the same.

Then as you get to the Nature Reserve. most people seem happy to provide a bit of space for you to cycle through, I generally give a single ting of the bell and so far although quite a few people jump in fright no-one has jumped into the Lode. I should point out that it is a quiet bell.  There are some though who glower at me. You can almost hear them thinking – “bl**dy cyclists get  in the way when I’m driving and now they get in the way when I’m rightfully taking up the whole width of the path”. Whilst there are signs on the path I do think that some people are genuinely surprised to see cyclists. I do hope that when the NT start their bike hire operation they will open up a few more permissive routes to help to minimise conflict between the different types of visitors.

I did make it safely through, although I have noticed that people tend to congregate near the cattle grid channels on the stretch of path between Monk’s Lode and Priory Bridge. I think they enjoy the “safari effect” of being closer to the animals and not “protected” by the fence. I heaved my bike onto the footbridge over Burwell Lode and took this picture of the earthworks over on Burwell Fen

I also took another picture of the Ha-Ha alongside Lodes Way  - as you can see the left edge, adjacent to the path is a bit steeper than the right hand edge. The hoof prints in the mud at the bottom show that the cows can certainly get down on the field side.

I then cycled up Newnham drove past Burwell Fen Farm, which seems to have 24-hour security, along with large lights and a generator running constantly, guarding the earth-moving plant being used to build the bund. This is the next ditch up from Drainer’s Ditch, there is a footpath to the left over to Burwell Lode.

At this point I wish I had taken my MTB, there wasn’t any plant operating, being a Holiday weekend, the operations have moved a fair bit of soil and clay around though. This had the advantage of creating a wide path to cycle along, but the surface was quite soft and crumbly in places. I cycled to the corner of the pyramid to Pout Hall Junction, well near it anyway, this is where Burwell Lode splits off from Reach Lode. You can see that in this picture the pylons seem to be quite far away as they run from Burwell over to Cambridge (over White Fen).

It seems here that a channel has been cut and filled with clay, with spoil along the left hand side.

There are different stages of completion around the fen, this is looking down towards Reach with Reach Lode just to the right. As you can see a fair bit if soil and clay has been lifted.

This is the source of the clay being used to line the bund, you get a reasonable view of the soil strata as well. there is a relatively thin layer of darker soil then a light brown thicker layer and then clay.  It appears from this link that the light brown stuff is either Lower Greensand or Upware Limestone, this bit of the Fen is close to what is called Verrals Fen on this map. The Lower Greensand is a water-bearing stratum with a positive pressure of 0.5 – 1.0m A.O.D.

I wonder if they will leave this pit, there is a tradition of abandoning clay pits which are then occupied by interesting wildlife. Mind you this is a pretty large pit H&S would probably require a 10M safety fence around it. (I guess this is what you would call a “borrow pit” pf National Debt levels.)

I was hoping to head down the side of Reach lode, but there were too many stingles and thistles as I was only wearing sandals on my feet. I did have problems as I walked with the loose dry peat soil getting into my sandals.  In the end I turned around and headed back down Newnham Drove to Lodes Way. I passed one lady walking three dogs who clearly enjoyed just wandering here and there sniffing around. In fact they enjoyed it so much they completely ignored me – or perhaps they could smell me from so far away I wasn’t interesting.

There were three deer in the middle of the fen, of course they stood still until I stopped and took my camera out and then they shot off.

Back on the Lodes Way there was a family group cycling – I headed up the Reach under-bank a little way and took a picture as the advance part waited for the stragglers.

Here is the view of the bund construction running parallel with Reach Lode. It looks as if the bund is actually to help contain the water up to around the soil level with the clay being put into a channel.

Another borrow pit – this one is alongside the Swaffham Bulbeck bridge.

On the way into Lode from White Fen there was a Marquee in a distance field (where the Lodestar Festival is held – 2nd September to the 4th of September 2011). So congratulations to Adam and Meghan, who according to the white banner were getting married.

To finish a video - one of a series about Wicken Fen.


  1. The borrow pit

    The British Geological survey 1:50000 series map (1981) of the area shows that directly under the peat (what's left of it) is mainly 1st Terrace river gravel, and the description in the accompanying book "Geology of the country around Cambridge" (1969) says:

    "Deposits in a patch mapped as First Terrace [TL551690] {within 100 metres of the pit - MikeC} in Adventurers' Fen consist of silt. Ditches showed 3 to 4 ft of it, overlain by 1ft of peat; the surface here is about 1-1/2ft above the level of surrounding peat lands. {All consistent with the current pit - MikeC} Small patches of the First Terrace between this locality and Burwell include clayey loams with coarse sand, small gravel and silt. They are considered to be the remains of a wider spread of the terrace, dissected before the rise of the sea level that led to the formation of the peat."

    I am not in any way a geologist, in fact after a hunt I found the map in question under my copy of Newnes "Mechanical Engineer's Pocket Book" (NB big pocket required), which gets more use, but as far as I can tell 1st Terrace is the most recent of the various silt and gravel deposits that are found in a river valley. The River Cam has meandered across the low valley between the chalk ridge to the east and the clay/greensand ridge to the west for thousands of years, depositing silt and small gravel all the time. There were several small streams joining it from the chalk springs in the east, which are now drained out to River Cam by the 4 lodes, and this bed of sand/gravel underlies the peat.

    Errr, think that's enough. If any real geologist reads this could they correct me please?

    I'll save a long diatribe on the NT renaming of land for another time.

  2. Mike, thank you, it now makes sense to me and I am certainly not a geologist. (One school friend became a geologist and went into the Oil industry.)