247 April 2015 - Gryffe Advertizer

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LOCAL
history
The Draining of Castle Semple Loch
Around 13,000 years ago, all of Renfrewshire west of the Black Cart was
an island in the Clyde, twice the size of Arran and almost as dramatic. It is
a sobering warning of the potential effects of climate change, that a warm
period between glaciations had raised sea level by around thirty metres.
At that time, it was possible to sail through the Lochwinnoch Gap from
what is now Paisley, west to the Ayrshire coast at Irvine. Today this seems
ridiculous, yet the Eglinton family tried to do the very same thing with a
canal, until their ambitions dried up at Johnstone, less than half way from
Glasgow to the coast.
Castle Semple Loch from Kenmuir Hill
Half way along the Lochwinnoch Gap lies Castle Semple Loch, a focal
point of the country park of Castle Semple Country Park. Three hundred
years ago, Castle Semple Loch and Barr Loch were one single stretch of
water, six kilometres long. The lochs are only two or three metres deep, and
the ground underneath is rich in decomposed vegetable matter. From the
1680s, a number of ambitious engineering projects were carried out to drain
away the water, and create hundreds of acres of fertile farmland. The first
scheme was more than 300 years ago, when the Semples began a scheme
to make Castle Semple Loch ‘Meadow-Ground’.
Johnstone History Society
The next meeting of the Society is on Tuesday 14 April in the
Masonic Hall, Collier Street, Johnstone at 7.30pm.
The speaker will be David Mitchell
and his subject is “Scotland’s
Iron Founding Industry”. David is
the Director of Conservation with
Historic Scotland.
Part of his job with Historic Scotland
is to care for the 345 properties and
their collections which are held by
Scottish Ministers on behalf of the
people of Scotland Visitors and
new members will away be made
welcome at our meetings.
The Johnstone History Museum
situated in Morrison’s at the
Collier Street is open Wednesday
to Friday and Saturday from
10.30am till 4pm and is manned
by volunteers from the Society.
We have a range of books, maps
and publications on sale in the
museum.
At its east end, Castle Semple loch drains away down the Black Cart via
Johnstone, to the join the Gryfe and the White Cart, before meeting the
Clyde at Inchinnan. Each successive drainage scheme had two main
features. Firstly, the Black Cart was deepened at its outlet from the loch, to
allow the water in the loch to drain away more easily. A dam and sluice were
built at the outlet to allow the water level to be controlled. Secondly, as the
loch emptied, a canal was dug down the centre to drain the water towards
the Black Cart. The burns which flowed into the loch were channelled into
this central canal. At the time, the Semple family were in decline, and the
initial drainage scheme had limited results.
In 1726 Castle Semple was purchased by sugar planter William McDowall,
on his return from the Caribbean. McDowall purchased Castle Semple
estate specifi cally ‘in expectations of making it a profitable purchase, in the
hope of draining the loch of about 500 acres, which will be of more value
than the estate’.
© 2015 Stuart Nisbet, Renfrewshire Local History Forum
Next month: Draining Castle Semple Loch, 2