Monitoring and predicting flooding on the Whittlesey Wash, based on my observations with no ‘fact checking’ from any external organisation.
East Delph Lakes Owner.
The North Bank Road runs parallel to the River Nene. When the river threatens to 'burst it's banks' the road is closed.
High rainfall is an obvious cause of this flooding. The River Nene catchment area is shown on the map. When trying to predict the probability of flooding, it's important to only monitor rainfall within the catchment area. Any rainfall outside the catchment is of no relevance as it cannot end up in the River Nene.
Rainfall in the catchment area can be monitored using the Met Office Weather App. Their 'UK Weather Map' offers historical rainfall, current rainfall and forecast rainfall, it's a very useful tool to work out how much rain has fallen in the catchment rather than just your local area.
In addition to the Met Office App, the Met Office Long Range forecast provides useful information when planning ahead.
Water takes about five days to travel from Northampton to Peterborough.
River levels are available via online monitoring stations. Some of these stations are on the map.
The government website is excellent as it allows you to follow links looking at river levels upstream and downstream along most of the River Nene. Click here for River Nene at Kislingbury.
When water levels reach 3.6 AOD at the Dog in A Doublet sluice water begins to flood onto the Road.
Using the link above scroll to the bottom of the page, you'll find useful graphs with historical data.
Tides have a huge impact on any flooding. The shaded blue area of the graph opposite shows the daily change in water levels due to the tides. When the blue shaded area goes over the green line there will be water on the Northbank Road.
The West Lighthouse Tide Timetable is critical to working out how much water can potentially flood.
During the periods when river levels are high it’s ‘good news’ if tides are peaking below 3m. When tides are peaking above 3m during the period of high river levels, the potential for flooding is greater.
This is because ability of water to flow through the Nene and out to sea is reduced as the tide rises and moves upstream from the sea. ‘Tide lock’ can occur at the Dog in a Doublet sluice stopping the ability of water to move downstream.
High tide at the Dog in a Doublet can be calculated by adding 2.5 hours to high tide at West Lighthouse.
See bottom of page for PDF files of tide timetables.
The Whittlesey Washes south of the River Nene near Peterborough is a large area of open land, surrounded by embankments, which act as a flood storage reservoir when high tides and high river levels coincide.
A good indicator that the Whittlesey Wash is about to flood is the closure of the North Bank Road.
Water is released into the Whittlesey Wash via Stanground Sluice.
The sluice opens when river levels there reach 3.8 AOD. The higher the river level the wider the opening.
Stanground sluice will close again when river levels have reached 3.6 AOD.
Water is drained from the Whittlesey Wash at Rings End. This can only happen when river levels and tides have sufficiently dropped.
The flow chart illustrates how water moves through the flooded Wash.