Have you ever wondered how the water flows into the Lake at Chiswick House and the link with the Thames? In our latest blog, IGarden Tour Guide, June Ford-Crush, dives into the details. 

As a Garden Tour Guide I am often asked about the water in our lake and how it links with the Thames – and I was interested to find out more.  Conor our Ranger was very helpful in explaining it all, and he even offered to let me come along the next time the controls were adjusted down by the river. An offer I couldn’t refuse!

So on a nice Autumn morning, I had the privilege of seeing inside the little Sluice House (or Penstock House to give it its correct name) on Promenade Approach Road down by the Thames where the controls are.  I have passed this building many times, but in all the years I have lived in Chiswick I never knew what was inside! It is the responsibility of the London Borough of Hounslow, but guardianship is in the hands of Chiswick House – and in particular our Ranger Conor.

In the summer, the lake water evaporates more than in the winter, so more water from the Thames needs to come in, and of course the reverse in the winter months – so it needed turning down.

Inside the hut is a winding mechanism to adjust a vertical baffle.  It was adjusted by a few turns with Conor on one side and Richard Sales on the other side of the wheels.  It is a 2-man job.  Utility covers were lifted to look down and check that everything was in order, and the hut was locked up again until the next time. You can see the actual sluice gate with a flap which allows the water in on the bank of the river nearby if you look closely.

Richard will now check the levels at the lake – it is monitored where water enters the gardens from the culvert by the wooden bridge at the south end of the lake.  The water loss is approximately 3/4cm per day. He is guided by the tides, and checks this from the timing at Tower Pier – so he can check if water is coming in and if they have got the mechanism right.

So what about the plastic pipe which we used to see in the lake?  This was used to circulate the water, but it got full of air and no longer worked – it rose to the surface and the garden historian David Jacques called it “Chiswick’s own Loch Ness Monster”.  The pipe has now been removed – but what about the nesting birds who used it?  Well, some parts have been retained for them, so all is well.

Previously there was an automatic system in the penstock house with a pump – but this did not work well and was unreliable – so it is redundant.

So it is back to the Edwardian system – the mechanism was installed by Frederick Bird & Co of West Drayton, Engineers and Iron Founders in 1922/3.   Even though it is back to the old-fashioned way of adjusting it by hand, it works perfectly – and with a constant team effort, it ensures that we can enjoy the gardens and the lake we all love.