Upper Bulbourne Readings for September 2020 submitted by Bob Farrer

Dear All,

Here is the report for September:-

34 mm of rain fell on Dudswell during the month. Over half of the total came as heavy showers on the 23rd and 24th. Without this brief deluge it would have been a very dry month.

Data from the four ‘dipping’ points:-

These reading were made on the afternoon of September 29th.

  1. Dudswell Bridge. 2.10 metres below datum. Stream bed is dry.

  2. Northchurch Recreation Ground. Casing broken. No reading possible. Stream now typically one metre wide with a trickle flow of clear water between 4-5cm deep.

  3. St. Mary’s Primary School, Northchurch. 1.50 below datum. Shallow stream barely 1 metre wide. Trickle flow of clear water roughly 5 cm deep.

  4. Billet Lane, Berkhamsted. Stream is now dry here. Reading is 1.62 metres below datum.


The water table is gradually retreating although it is still far higher than at this time last year.

Susan Holmes has been on a course measuring pollution in local streams. She has passed me her findings for the Bulbourne measured at three points:-

St. Mary’s Northchurch.
Nitrates (as NO3) 1-2 parts per million (ppm). Phosphate (PO4) 0.05-0.1 ppm

Waitrose, Berkhamsted.
Nitrates 1-2 ppm. Phosphate 0.05-1.0

Rising Sun Inlet in South Berkhamsted, where the river flows into the Grand Union Canal.
Nitrate 1-2 ppm. Phosphate 0.1-0.2ppm.

These figures are all in the range ‘Good to Very Good’, which is encouraging. Heavy metal pollutants were not assessed.

GUC pumping from the aquifer into the canal:- Both the Cowroast and Northchurch pumps were OFF at the time of my readings.

Nature note:-
There are many more Herons on the canal this year. This is strange because the path is far busier since the Covid lockdown has brought lots of walkers and cyclists to this area. Herons dislike people and dogs and generally take off as walkers approach, whereas Mallard ducks will stand their ground and let my dog pass within a foot of them, apparently unconcerned. I have some photos of Herons fighting but they are rather blurred.

Kind regards,