The Lee Valley Regional Park extends some 25 miles down the valley of the River Lea, from Ware in the north deep into London as far as the Thames in the south, straddling the borders of Hertfordshire and Essex.
The gravel beds of the valley were left behind by retreating ice at the end of the last Ice Age 10,000 years ago. There has been massive extraction since the 1920s and this has created a huge complex of lakes and marshes in the northern part of the park, while in the south there are a number of large water supply reservoirs. Together these provide an area of open water to rival even the Norfolk Broads.
It is a spectacular place to watch birds, both on the open waters of the gravel pits and reservoirs, on the many channels and streams, and in the surrounding marshes and meadows. But you do not need to be especially interested in birds to enjoy wandering around in this tremendous (in both senses) wetland.
The largest areas of accessible open space are around Waltham Abbey, including the River Lee Country Park and, just south of Waltham Abbey, Gunpowder Park, a new country park mainly on reclaimed land once used for testing munitions.
Visiting
For car parks on the Essex side leave the M25 at junction 26 and follow the signs to the Lee Valley Park. Car parks are also signposted from the B194 to Nazeing. For the Cheshunt car park, turn off the A10 on to the B198 and follow signs from there
Train to Cheshunt station from Liverpool St for River Lee Country Park or to Waltham Cross for Cornmill Meadows (bikes welcome). Many bus services serve the area: routes 505 and 250 should be most useful for access from Essex.