The Grand Union Canal links Birmingham to London with a waterway which is 145 miles long and contains 166 locks. This cache is one of a series to be found along or close to the Hertfordshire/Buckinghamshire stretch of the canal.
The cache is hidden not far from to a pumphouse housing a pump which draws water from a deep borehole into the chalk to feed the canal. In the days before the pump was installed, in 1943, Northchurch used to be the scene of long lines of boats moored up in the dry summers as the canal engineers struggled to maintain the water supply at the summit level, which was constantly being drained by the use of the locks at either end. Every time a boat crosses the summit level, it uses up 200,000 gallons of water.
You are looking for a small square tupperware box which has been cammoed. Take care for muggles as this can be a busy spot as it is by a busy road and you are not too far from habitation. There is no need to get too close to the water, but if you do, be very careful as the water is deep. Children, keep a tight hold on your parents to stop them being silly and falling in!