Those interested in Stephen Nunn’s article on the River Blackwater (Standard, February 8) may also be interested in a small booklet of 40 pages, entitled Down the Chelmer and up the Blackwater, by Vernon Clarke.

This was published in 1978 at 75 pence, and included some delightful drawings by Joan Clarke.

Although out of print, I obtained a copy recently from a local bookseller.

It differs slightly from Stephen’s version in that the source quoted by Stephen is described as a secondary Headstream.

The primary source being quoted as beside the Debden airfield, some 380 ft above sea level, and half a mile from the source of the River Chelmer. These two rivers meet again at Beeleigh.

During my almost 40 years as a local water scientist, I travelled intermittently along most of the length of these rivers, in addition to their tributaries.

David N. Williams

Washington Road, Maldon