Archive for the ‘Making ponds’ Category

The New Pond: an update

January 4, 2010

The new pond today is completely frozen over: beneath the ice, the water is crystal clear.

The bare gravel is a good sign: a tough environment for plant growth which should favour a wider variety of marginal and aquatic plants than more nutrient rich soil.

The edges are slowly being colonised by Creeping Bent, moving in from the lawn. This will provide a good edge habitat which I’m happy to let develop gradually.

Unlike the old pond, which has had no plants added, in the new pond I’m slowly, rather haphazardly, adding plants from local wild sources.

In the new pond so far we’ve added:

– Fools Watercress

– Water Mint

– Jointed Rush

– Water Violet

– Blunt-leaved Pondweed (Potamogeton obtusifolius) – this is probably the most pollution sensitive plant added so far. It will be interesting to see if it survives as generally the submerged plants are the hardest to get to establish.

– Brookweed (Samolus valerandi): a bit of a local rarity this, but common in the bare ground habitats of gravel pit margins around Abingdon.

I deliberately added a small amount of Common Duckweed (Lemna minor) but it looks as though it hasn’t survived – it will be interesting to see whether it reappears in the spring.

None of the plants have been ‘planted’: mostly I just throw them in to fend for themselves, though occasionally I’ll weigh them down with a bit of brick until they start rooting into the gravel.

The new pond just after completion in April

The pond in April, just after filling.

The turves at the edge have now grown back completely: just after the pond was finished (above) they looked a bit dried out but they came back to life, as expected.

One mystery I haven’t got to the bottom of yet is the quite high conductivity. It’s around 200, occasionally exceeding 250.

Why its higher than the old pond, where conductivity rarely reaches 100, isn’t clear yet. It maybe minerals leaching from the turves (though why this should be happening more on this pond than on the old pond isn’t obvious), or something to do with the gravel.

We’ll probably have more of an idea when we get a proper water analysis done on the pond later this winter.

But even at 250, this is much better than most ponds in Oxfordshire where a value below 400 or 500 is a rarity, the effect of the almost universal pollution of rivers, lakes and ponds that affects the county.

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Start again….

July 12, 2009

At the end of April I posted this picture of the recently nearly completed new pond.

The new pond on 26 April 2009

The new pond on 26 April 2009

I didn’t make much progress after that. A hectic spring and early summer – busy with Big Pond Dip, the Blue Peter pond makeover, setting up a new research programme on Water Friendly Farming and a myriad other things meant the pond simply had to be on the back burner.

And in the meantime all was definitely not well with the water quality: the conductivity was much higher than I wanted. By the end of last week, when it reached 320, I decided enough was enough.

So out with both baby and pondwater to start again with new clean water.

So here is the pond reset, just before I added the water (I’m writing this on a train and have realised I didn’t download the last of today’s photos). Anyway, the pond is now re-filled with rain water, from the water butts, and the conductivity is back down to around 85.

The pond before refilling today 12 July 2009

The pond before refilling today 12 July 2009

I don’t really know why the conductivity got so high over the last two months. I have a feeling that when we emptied a tap-water filled paddling pool earlier in the summer onto the lawn some of that water drained into the pond.

So now its time to get on with putting down clean washed sand and gravel to provide a substrate, and to add some locally sourced plants.

The new pond

April 25, 2009

copy-of-thenewpond25april2009

Fast progress today, and suddenly there is a pond.

Now just the tidying is needed, and some rain to complete the filling.

Digging at Barton Meadow

April 16, 2009

A few shots of the digging at Barton Meadow in Oxfordshire.

The work is being done by the Abingdon Naturalist’s who look after the area, funded by the Heritage Lottery Fund. The ponds are specifically for water voles: there are loads in the area, which is on the floodcplain of the Thames at Abingdon, so they should move in pretty quickly.

Water quality isn’t perfect here: conductivity is over 600. But fortunately clean water isn’t too important for Water Voles: they mostly feed on reedy plants, like Bulrush and Reed Canary Grass, which grow well in polluted water.