The best assurance of a park’s future is a band of committed local people. The Tarn, a small but picturesque park beside Court Road, near Mottingham Station, has had such a group for a year now.

Their aim – to improve the park both for the community and for wildlife. The Friends, chaired by Carole Thomas, hold regular meetings, workdays and other events. For 2009, work sessions take place on the 3rd Saturday of each month. The first, on 17th January, saw 10 volunteers get stuck in – priority, turning the small pond into frog habitat.

Dominating the park is the lake, of ancient though uncertain history. Perhaps, as a fishpond, it originally supplied Eltham Palace in medieval and Tudor times. It is fed from headwaters of the Little Quaggy, a tributary that joins the River Quaggy near the Dutch House on the A20.

Alongside the lake, a well preserved ice-house built in about 1750 by the Shaw family, is a reminder of a former method of refrigeration. It seems likely the Shaws also enlarged the pond in the 1780s as a scenic feature for their house, Eltham Lodge (today’s Blackheath Golf Club HQ).

For the Friends, improving the health of the lake is a prime objective for which substantial funding needs to be found. As a preliminary step on their behalf, Thames21 undertook a base-line survey in early 2008, a copy of which was forwarded to Greenwich Council. A second survey, initiated by Thames21, took place on 27th November 2008, primarily to investigate the fish population. The survey was conducted by students from Hadlow College, with the Environment Agency in attendance.

As expected from the evidence of water pollution, results were unexciting. In marginal sweeps of the lake, only one gold fish was found; sweeps around the islands produced no fish at all, sweeps in central stretches produced around 200 sticklebacks, all returned alive and unharmed to the water. Stickleback and goldfish are exceptional in that they can survive in poor quality water, feeding off seeds, berries, bird excrement, invertebrates and algae. The Environment Agency is due to carry out further water tests.

Though currently of poor ecological value, the lake offers enormous potential both for wildlife and as a community amenity. So does the Tarn in general – the Friends have an impressive Project List. The next two work sessions are Saturday 21st February and Saturday 21st March, 10am to 2pm.

Fish population survey on 27th Nov 2008

Birdwatch survey on 24th January 2009

Blackbird 2
Magpie 2
Blue tit 6
Robin 1
Carrion crow 1
Jay 1
Coal tit 3
Mallard 28
Collared dove 2
Ring-necked parakeet 11
Feral pigeon 20
Canada goose 14
Great tit 2
Cormorant 1
Long tailed tit 2
Tufted ducks 2