Filling the Rills!

The Rills are finally completed and are ready to be connected to the feeder ditches which run from the River Cam into the washes.

The water table in the past has been governed by the aquifers that run through the limestone and occasionally join the surface soil keeping the area wet.  When the Cam floods however water flows over the surface of the soil but the clay lining of the ditches does not allow the water to flow away.  By joining the new rills to the ditches and in turn the island scrapes to the rills even slight increases in River level can be used to fill the waterways.  Simple non-return valves where the ditches join the River Cam stop the water flowing back out again.  Hopefully this will ensure we have good areas of water well into the summer, just when breeding waders and their chicks need it to feed.