Water situation for Upper Ivel – Dec 2022
All data presented courtesy of the Environment Agency and Met Office (Crown copy right
2022)
Rainfall:
December started off relatively dry with cold settled conditions dominating. On the 12 th of December we were all
woken to the surprise of 3 inches of snow, the cold weather prevailed until 18-19 th when warmer weather saw the
snow melt. As we neared Christmas and New Year celebrations, we saw the return to a succession of Atlantic frontal
systems bringing rain. Post thaw conditions have been Ideal recharge conditions for the aquifer. December’s rainfall
in the Upper Bedford Ouse catchment (includes the Ivel) was 99% of Long-Term Average (LTA). In the last Quarter of
2022 (Oct- Nov-Dec), we have seen 150% of expected rain (versus LTA).
Monthly rainfall totals for the past 12 months as a percentage of the 1961-1990 LTA
However, there is long way to go to make up for the lack of rain throughout 2022.The blue line tracking well below
the expected annual rainfall of 600mm (LTA)
Soil Moisture Deficit (SMD)
The Met Office MORECS grid squares covering the Ivel has improved to 0-10mm SMD by the end of the month
indicting that the soils have reached field capacity. You will have no doubt noticed standing water in some parts of
fields. Recharge of the chalk aquifer is now very likely in response to rainfall events. The west of the region has
received more rain over the last few months, and this is reflected in the SMD chart compared to eastern areas.
Definitions:
Soil Moisture deficit (SMD) – The difference between the amount of water in the soil and the amount of water that
the soil can hold (field capacity).
Field Capacity (FC)-The amount of water the soil can hold is generally called field capacity which is the amount of
water that remains after gravitational forces have drained water from the soil.
Soil Moisture deficits for week ending 31 December 2022. Data based on MORECS data for real land use.
Springs and River flows:
The main spring at Ivel Springs in Baldock remained dry throughout December 2022.
The second spring at the Ivel Springs nature reserve (upstream of culvert) in Baldock was still dry on 30th December
2022.
No flow at Blackhorse mill in December 2022
Changes during December – 3 springs now flow in Radwell meadows.
Any current standing water in the riverbed at the iron bridge and Norton (upstream of the Radwell meadow springs)
is the result of A1/M road / hard surface runoff.
Standing water in the Ivel springs reserve is a result of rain events and surface water run off from Baldock town.
The river remains low through Radwell but is recovering from Stotfold onwards.
The river Ivel flows are officially measured at Blunham. The river has been low to notable low through the summer
but returned to normal (green zone) during October. During November and December, the river at Blunham has
responded directly to significant rainfall events (relative dry condition in first half of December followed by a wet
second half of the month).
Reservoir Stocks:
Water from the Ouse is transferred at Offord into Grafham Water.
Recovery of reservoir stocks in Grafham Water remains slow with the reservoir currently only 67% full (blue line on
graph) (Notably Low). The current stock levels are a long way from the normal operating level of 90%+.
End of November Grafham Water reservoir stock compared to the Normal operating Curve, Drought
Curve and 1995-1996 stock levels.
Looking forward:
Thank fully Oct- Nov – Dec 2022 has been wet with 150% of LTA.
Much more rain is needed in Jan – March 2023 to support the continued recharge of the aquifer and to improve the
chances of flow of the chalk springs in Baldock, Norton and Radwell in the spring and summer months 2023.
We know Affinity Water will abstract all the water they can from the boreholes around Baldock and Letchworth.
within legal and physical limits irrespective on how much rainfall/ aquifer recharge, With no regard for the
environmental consequences to our precious chalk stream.