Water situation for Upper Ivel – September 2023.
All data presented courtesy of the Environment Agency and Met Office (Crown copy right 2023)
There was a heatwave in early September, with the highest temperatures of the year in East Anglia being recorded during the month. During the second half of the month, high pressure gave way to the low-pressure systems coming in from the Atlantic this being more typical of autumn conditions. This resulted in above average rainfall (130%) in
the Upper Bedford Ouse catchment.
Soil Moisture Deficit (SMD)
The soil moisture deficits [SMD] by the end of September had reduced to 70-80mm and was considered in the normal range for this time of year.
Soil Moisture deficits for week ending 30 Sept 2023. Data based on weekly MORECS data for real land use and compared to an analysis of historic 1961 – 1990 LTA dataset.
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).
Ground Water (GW):
The groundwater levels across East Anglia’s western region continued to recede through September as expected for this time of year but remain in the normal range compared to historic levels.
Springs and River Flows:
The main spring at Ivel Springs in Baldock started to flow on 14 th January 2023 but has ceased to flow as of 24 th June 2023, effective flowing for only 23 weeks in the year. This spring should flow year-round albeit at reduced flow levels in late summer / early autumn….Historically the mill at Blackhorse (closed in 1870s) would have milled wheat
year-round for the people of Baldock and surrounding villages.
The second spring at the Ivel Springs nature reserve (upstream of culvert) in Baldock started to flow on 1 st January 2023. Surprisingly we have continued to see a minimal flow into September, albeit at extremely low levels. This is important as it has allowed a slow recovery of flora and fauna in the upper reaches.
Flow at Blackhorse mill started by the end of the first week in January 2023.Again we are pleased to report that there is still minimal flow at Blackhorse mill at the end of September 2023.
The river Ivel flows are officially measured at Blunham. Heavy rain events in the second half of September saw a spike in flow which returned to normal by the end of the month(Green Zone).
Water from the Ouse is transferred at Offord into Grafham Water reservoir. After twelve months of reduced capacity Grafham Water reservoir has finally returned to full capacity during June – Sept 2023 (90% -blue line on graph) which is in line with the normal operating levels.
End of Sept 2023 Grafham Water reservoir stock compared to the Normal operating Curve, Drought Curve and 1995-1996 stock levels.
The upper reaches of the Ivel have managed to maintain a minimal level of flow throughout the summer months. This is the best outcome we could have hoped for considering the previous 18 months and continued abstraction practises of Affinity Water.
Looking forward this autumn Affinity Water will start the river restoration at Ivel Spring Nature Reserve so look out for some channel improvement works. Also, we can expect “testing’ of the augmentation scheme to get underway. So, look out for activity at the Ivel Spring. The current planned augmentation of a mere 0.54 Ml /day is far short of the desired re-naturalisation of flow Revivel demand but at least we should no longer see a dry riverbed all the way to Radwell.