250 THE ESSEX NATURALIST
Climatic Influences in the Epping District
BY JOHN GARRETT, B.A.(Oxon).
The area described in this brief study has no regional or climatic entity,
but, consists of approximately 130 square miles of South-West Essex
extending roughly from Harlow to Walthamstow and to Chigwell, draining
to the Rivers Stort, Lea and Boding (Fig. 1).
RAINFALL
The Epping Forest and Epping Upland ridges stand out clearly on a
rainfall map (Fig. 1): Epping, at 360', has an annual average rainfall of
30", while Waltham Abbey, only four miles away, but 300' lower, has 23.3".
The lowest rainfall is in the south-west, at Lea Bridge, where the yearly
average is 22", though less than four miles to the south-east a part of
Dagenham has under 20", and is one of the driest places in the British Isles.
The driest month is April, with an average of 1.5" in the Lea valley, about
6 per cent of the yearly mean. January to April has less than 28 per cent