The Alconbury Brook Flood Group
Current Flood Data
LIVE DATA
Alconbury Brook - Alconbury Village
Welcome to the LIVE DATA page for the brook in Alconbury Village, we're hoping to have more pages like this in the future.
​​
Below you can see a chart showing the current depth of the brook downstream of the village over the last 2 days and below that the Soil Moisture Measurements, daily, for the last year (or so*).
​​
-
​The normal range for this sensor is between 0.5 and 2 meters.
-
A flood alert is issued by the environment agency around 2.4 meters.
-
​​If the level of the brook is 1.5 meters before heavy rain, the likelihood of an alert is much greater.
​
We're working on putting this along side a rainfall gauge as through general observation we have noticed the following
-
In winter, assuming the brook is empty, it takes 30mm of rain to trigger an alert.
-
In summer, assuming the brook is empty, 30mm may not even change the level of the brook at all.​​​
The amount of water stored in the soil makes a big difference to the chance of flooding after heavy rainfall. For example, when the soil is full of water, and the brook is partially full, 20mm of rain in 36 hours is enough to trigger a Flood Alert and 25mm in the same time period may trigger a Flood Warning.
​
Most of the soils in this country are made up of a variety of particles and the space between these particles (soil space).
​
After heavy rain, all the spaces between the soil particles can be completely filled up with water. This is called 'saturation'. After two or three days usually most of the rainwater drains away down and sideways.
​
However, there is a weak attraction between the soil particles and the water, so some water is retained within the soil. The amount of water that stays is called the Field Capacity and this water is available to plants.
​
The attraction between the water and the soil gets stronger as more is used up by plants. Eventually the attraction is so large that many plants are unable to use the water. This is called the Wilting Point. Some plants (eg. grasses) are a bit more resistant to wilting than others (e.g. cucumbers).
​
The germination, growth, and safe working of the soil is best between Field Capacity and Wiling Point. Using machinery on soil above the field capacity can lead to compaction and reduction in germination, plant growth and yields.
​
* The Soil Moisture Chart gets all data available for the last 12 months and shows it daily, but this is a new chart so we're working out the kinks.