Affinity Water supplies water to parts of the north of Brent. They warned a
few weeks ago that to avoid a hose pipe ban there would need to be above
average rainfall over the Autumn and Winter to make up for the impact of the summer
drought. If rainfall continued below average, they would need to introduce a
hose pipe ban in 2023.
Following the recent heavy rainfall some people have suggested reservoirs
would soon be back to normal levels. Yesterday I walked through Fryent Country
Park to see how the many ponds were affected by the rain. giving an indication
of what might be happening to reservoir levels.
Some were still completely dry and covered in vegetation. Barn Hill
pond on top of Barn Hill had recovered somewhat but still well below normal
levels. It has a different geological base from the other ponds and there's
some mystery about how it fills with suggestions of springs in the area.
The other ponds have a clay lining. Clay used to be 'puddled', beaten down
to remove all the air, making a waterproof surface that retained water in the
pond. Tools might be used to beat down the clay but in the past cattle would be driven through to compact the clay and in modern times when ponds are constructed in schools pupils in wellies do the job!
In a drought the clay is exposed to the air and the sun's heat and will
crack, leading to the loss of water when the pond refills. Cracks can be seen
in the dried-out pond in the photograph above. Loss of ponds in the Country Park will impact on the survival of already threatened frogs, toads and newts as well as other pond life such as dragonflies and damsel flies that give much pleasure to visitors.
Maintenance work has been done on some of the ponds and may explain the
differences in water retention. Below are some of the ponds I checked
yesterday, beginning with Barn Hill pond.
