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 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.
