Upper Bulbourne Monthly Report, November 2020 submitted by Bob Farrer

Dear All,

Here are the ‘dip’ readings and observations made on November 30th.

  1. Dudswell Bridge (highest datum point)
    There is a trickle flow of clear water in the channel. Flow rate is less than 1 litre/sec.
    The dip is 1.2 metres below datum

  2. Northchurch Recreation Ground.

No reading possible as casing is broken. The stream here is typically 2-3 metres wide but adjacent land is flooded as far as ten metres to the northeast of the stream in some places.
Central sections are about 20cm deep with a brisk clear flow.

  1. Northchurch Primary School.
    Vigorous flow of clear water 2-3.5 metres wide and upto 40 cm deep, in a few places to the west of New Road.
    Dip reading is 0.69 metres below datum.

  2. Billet Lane Berkhamsted (Lowest datum point)
    Very strong turbulent flow of clear water about 20 cm deep through all three under-road tunnels, despite considerable re-growth of cress.
    The dip is 1.15 metres below datum.

Pumping of Groundwater.
The GUC pumps at both Cowroast and Northchurch were off at the time of these readings. The CRT has been doing much engineering work lately in the Northchurch area. This is usually associated with increased pumping, yet there was no evidence of that when I made these measurements.

Rainfall.
58 mm of rain fell on Dudswell in November, 80% of this was in the first two weeks. Although often cold, the second half of the month was mercifully dry. Such a contrast to the awful soaking we endured in October.

Comments.

For about a fortnight during the middle of the month a large group of Moorhens (twenty or more) gathered during the afternoons about 100 metres north of GUC lock 47. I tried to get photos but they just look like dots in the gloom. They are very skittish birds and often quite territorial, so I have no clue why they gathered in such numbers.

Stay safe 'til the vaccine arrives,

Bob