Rivers with Griff Rhys Jones started tonight on BBC1.

This is a five part series for the summer holidays.

Stand by for his River Lea episode on Sunday 16 August.

This month sees the centenary of the first British flight which took place in the Lee Valley.

Flight pioneer Sir Alliott Verdon-Roe, working from a railway arch on  Walthamstow Marshes managed to get off the ground on 13 July 1909.

The anniversary was kept on Sunday 12 July in front of the arch when Eric Verdon- Roe unveiled an exact fully flyable replica of his grandfather’s Roe I Triplane. This was the first all British aeroplane.

The ground today is not suitable as a runway but there will be flights attempted at RAF Woodvale.

Look out for the blue plaque on the arch near by the towpath between Springfield Park and Lea Bridge.

See page 108.

More boats and barges should be seen on the River Lea in London after the opening today of Three Mills Lock.

This is the first new lock to be built in London for more than 20 years and  today being World Environment Day it was appropriate that Environment Secretary Hilary Benn should perform the opening ceremony. He is also staying in office as part of the reshuffled cabinet.

“We want the London 2012 Olympic and Paralympic Games to be the greenest games ever” he said. “Funding the Three Mills Lock will not only take many lorries off local roads, reducing thousands of tonnes of CO2 and local congestion, it will also provide a green freight route for the redevelopment of East London, and open up the waterways for boaters, walkers, and cyclists.”

The lock is just east of Three Mills and on the Prescott Channel which is part of the Bow Back Rivers network threading through the Olympic Park. It’s a spot which was well-known briefly as the site of the first Big Brother programme. It’s also where stones from the Euston Arch was dumped and thanks to this work they have been retrieved.

The footpath linking Three Mills to Three Mills Lock is currently closed.

Our ‘Walk London’ Lea Valley walk upstream from Limehouse took place in perfect weather: blue sky and sun but also a breeze.

Three Mills was empty but looked like a film set. Tesco saved the day with its toilets.

We followed two Bow Back rivers to reach the stretch of Greenway open. But this week security fencing has been put up at the Olympic viewpoint which is a pity.

Good to see old and new faces on the walk.

There will be another one on the last Saturday in September. Details will be posted here in late August.

Walk London organisers are suggesting we wear suncream, take a hat and and carry plenty of water on the walk tomorrow.

Sounds good!

See you tomorrow at Limehouse Station, 2pm.

I have checked our route for the Walk London event on Saturday and yes we can go up on to the Olympic viewpoint.

We shall take an unusual route between Three Mills and the Olympic Park as so many paths are closed but this is an unusual time. We can use a quiet canal-side path on the Bow Back Rivers to get there.

This week I thought that the Olympic Stadium really did seem huge for the first time. It is a big change from February and it is a landmark which will be with us for the rest of our lives. Walkers will be surprised.

Much of the blue perimiter fence has come down so now when on the towpath north of Old Ford Lock you can see into the Olympic Park.

We meet on Saturday 30 May at 2pm outside Limehouse Station.

The end is at Hackney Wick Station.

It’s free. All welcome.

And the weather forecast for Saturday is “sunny”

The latest information on the towpath closure between Ponders End and the Lea Valley Viaduct to the south is that it will remain closed between 7.30am and 6pm daily until Friday 10 July.

Diversions remain in place via Lee Park Way and Meridian Way.

The Electricity Alliance, a partnership between National Grid and Balfour Beatty, is currently refurbishing the overhead electricity transmission line between substations at Waltham Cross, Brimsdown and Tottenham. Work involves replacing the overhead line fittings, painting and work on the steel structures.

National Grid Project Manager Simon Chandler says: “These closures are needed to ensure that we can carry out the work safely. We apologise for any inconvenience this may cause and we will make every effort to ensure we complete the project as quickly and considerately as possible.”

We shall be going up to the Olympic viewpoint on the Lower Lea Valley walk on Saturday 30 May.

This event is part of Walk London’s ‘Spring Into Summer’ weekend and our walk also coincides with the Ramblers’ Get Walking Day.

We meet at Limehouse DLR Station at 2pm to walk north up Limehouse Basin, through Three Mills to Hackney Wick Station.

All Walk London walks are free.

www.walklondon.org.uk

The towpath between Ponders End and the Lea Valley Viaduct to the south is remaining closed this weekend 16 and 17 May.

The continued closure is due to essential work on overhead electricity cables.

But if work ceases early in the afternoon the path will be opened.

Those tempted to climb the barriers ought to remember that they will only come up against four further fences.

Although this work is due to continue until 10 July it it is hoped that continuous work now will result in an earlier completion date.

Pages 99 to 101.