Cuffley Brook

After the confluence of the two streams in Whitewebbs Park, the watercourse continues eastwards as Turkey Brook to join the River Lea near Enfield Lock.

There, it goes under the Flash Lane Aqueduct[2] (on a former course of the New River), before reaching a confluence with Turkey Brook, in the London Borough of Enfield, at the north-west foot of Forty Hill.

As a west bank tributary of the lower River Lea, Cuffley Brook came into being about 400,000 years ago, after the Anglian glaciation.

Until the Anglian glaciation, the River Thames flowed north-eastwards to Hertford via Watford, through what is now the Vale of St Albans, then eastwards towards Chelmsford and the North Sea.

[13] Prior to the Anglian glaciation, a "proto-Mole-Wey" river was flowing northwards from the Weald and North Downs, through the "Finchley depression" and Palmers Green, to join the proto-Thames somewhere around Hoddesdon, at what is today an altitude of around 60 metres.

It flowed into the newly diverted Thames, which at that time was spread over a wide flood plain extending as far north as Islington.

But, in Enfield, the engineers who constructed it took the New River on a loop going west, to the north of Forty Hill, and then across Cuffley Brook near Flash Lane (and, later, across an aqueduct there[2]).

For example, from the top of Plough Hill, Cuffley, the ground falls about 50 metres in altitude to the valley bottom in barely more than half a kilometre.

But we are currently in an interglacial period, and the streams would have been flowing more strongly than today at times of "high discharge, under cold climatic conditions".

Furthermore, as the River Lea itself cut down as it moved eastwards, it lowered the base level of its tributary streams, like Cuffley and Turkey Brooks.