The Merton Borrow Pit is located south of the M40 flyover between Merton and Charlton-on-Otmoor and is effectively hemmed in by the road from Merton, the M40 Motorway and the River Ray.
The term 'Borrow Pit' is used in civil engineering and describes an area of land where material is dug out for use in either construction or as fill elsewhere. Usually the material is taken and not 'borrowed'.
However, in this case, the Merton Borrow Pit was created (dug out) during the construction of the M40 Motorway but was flooded afterward. This flooding of the extremely and deceptively deep pit has provided a sustainable wildlife habitat and is managed as a nature reserve.
Despite its noisy neighbour, many wildfowl have been known to visit and the close proximity of the RSPB Otmoor Reserve is undoubtedly an important factor in this.
In addition to the wildfowl, butterflies, a plethora of dragonflies and damselflies can be seen, especially around May when they start emerging from the water ceasing their larval stage.
Here are some fabulous pictures thanks to Zella Simmons of the building of the M40 and the Borrow Pit as a quarry