Earlsburn Reservoir

.. and the Earthquake of 1839

Illus: 1914 ¼ ins Ordnance Survey Map showing the location of the Earlsburn Reservoir at Earl’s Hill (National library of Scotland).

All water mills had problems with the unpredictable availability of the volume of water needed to drive their machinery.  In the winter there might be floods and in the summer droughts.  The larger the works the greater was the problem and the number of jobs reliant upon it.  One solution to this was to construct massive regulating reservoirs near the source to store water at times of plenty and then to release it down the water courses during shortages.  Over a large number of years from 1760 onwards the Carron Company constructed the Carron Dams for this reason, augmented by a reservoir at Dunipace.  In the early 1830s the mill owners and operators further up the River Carron around Denny agreed to combine resources to create one large reservoir up-river on a tributary called the Earls Burn.

“The Committee of Proprietors of the Reservoir for the better supply of Water to the Mills on the River Carron” was formed and in 1835 the reservoir was constructed about eight miles north-west of Denny.  The land at Cringate Muir occupied by the reservoir covered an area of about 60 acres (one source says that it exceeded two hundred acres).  The huge embankment along its south side reached a height of 22ft and a length of approximately 1,280ft.  The damhead was built of peat and earth with a narrow clay core of silty clay. The core extended down to rock but most of the dam was founded on peat.  This design was not unusual for the time, though the difficulty in getting materials to the remote site probably meant that the clay core was narrower than it might otherwise have been.

As with so many large civil engineering projects the actual coast of construction exceeded the estimates.  The consortium of mill owners became disunited as some of its members refused to pay the additional costs – or, in some cases, what they have promised at the commencement.  William Morehead of Herbertshire had been one of the main advocators of the scheme, but with his death it fell to his trustees to fulfil his obligation.  In the meantime, Herbertshire had been sold to William Forbes of Callendar near Falkirk.  The clerk for the Committee of proprietors wrote to Forbes:

“20th Feb. 1836.

            I have been desired by the Committee of proprietors of the Reservoir on Earlsburn respectfully to address you regarding it. –

            You are aware, no doubt, that a large Reservoir was sometime ago constructed, at very considerable expense, by certain of the Proprietors of Works upon the Carron, for supplying Water during the time of drought, when the River did not yield a sufficiency for the use of the Works upon it. – These parties have already expended upon this work £1,455, besides which there are outstanding claims, still to be discharged, to the amount of £356, while the money hitherto collected from subscriptions is only £742.-   Each of the Gentlemen of the Committee is already in advance about £300, and if not relieved will have still more to pay.   This has been owing partly to the expense of the work having greatly exceeded what it was calculated to have cost, and partly to some of the original Subscriptions to the undertaking having subsequently withdrawn or rather declined to pay their proportions, after the Work had been completed. – Among the latter may be instanced, the Trustees of the late Mr. Morehead of Herbertshire, who have declined to fulfil that Gentleman’s obligation, who was one of the first promoters of the Reservoir, and the Revd. John Burns of Garvald, who, after having Subscribed £100 – to the Work, has now declined to pay anything. –

            I may mention, in regard to whatever deficiency of funds may arise that the loss will fall upon five public spirited individuals who are well known to you, vizt., Mr.Cairnie of Herbertshire Printfield; Mr. Adam of Denovan Printfield; Mr. McRobie Carrongrove Paper Mill [Mr. Lusk Tenant]; Mr. Weir of Tanaree Corn Mill [Mr. Forrest Tenant]; and Mr. Gilchrist of theWoollen Mill. –    These Gentlemen feel persuaded, that however indifferently the former Proprietor of Herbertshire has acted in this matter, you will not tamely stand by and see them losers to any considerable extent by their public spirited conduct in this matter. –    It need hardly be observed, that there is no property on the Carron, already so much benefited, and likely soon to be still more so, by the expiring of current Leases, than your own Estate of Herbertshire, from the number of Mills belonging to it upon the Carron. –

… / The Committee, therefore, respectfully, but Confidently, look forward to your assisting them with a liberal Contribution to enable them to defray the expense they have been at in this important undertaking, and will be glad how soon they can be favoured with your views on the subject, that they may be regulated in their intended applications to some other parties whose properties have been improved by the Reservoir.”

(Forbes Papers 1230/5).

The mills were, of course, largely responsible for the depleted state of the river.  Although most of the water was returned to the river, much polluted, the additional evaporation caused by the lades and the drying processes at the printfields and papermills left it denuded.  The mill owners naturally blamed changes in the agricultural regimes in the upper reaches of the Carron and the increased use of the waters by the inhabitants of the area.  William Forbes had just taken up his seat in the Houses of Parliament and so correspondence and actions took longer than usual.  Nevertheless his initial response was evidently positive and so the three principal officers followed it up with another letter:

Denny 30th May 1836

       We the undersigned, being the Committee of proprietors of the Reservoir for the better supply of Water to the Mills on the River Carron, having met this day for the purpose of arranging matters connected therewith, beg leave to lay the following Statement before you.

       We have expended expences of a thousand Pounds already in constructing Said Work, besides have incurred a debt of another thousand Pounds which we feel anxious to be liquidated.

       As you are deeply interested in this matter having three valuable Mills on the River, besides what falls unoccupied, and as you were so good as state in your answer to Mr McLachlan’s letter to you, that you would assist us in defraying a proportion of the expence, we beg most respectfully to request that you will take the matter into your consideration, and inform us at your earliest convenience the amount of the sum you intend to advance.

       We need not state to you the advantages to be derived from a full supply of Water in dry Seasons to the Mill properties in the River Carron, in the now defective state of it   We remain                                                                               J. Gilchrist

                                                                               J. G. Adam

                                                                               Robert Weir

                                                                               Charles Garvie

(Forbes Papers 1230/14)

Forbes offered to subscribe £100 and the Committee thanked him, hoping that once the advantages of the scheme had become more readily apparent that he would be able to contribute more (Forbes Papers 1230/16).

The damhead was regularly inspected and in June 1839 it was surveyed by Mr Smith of Deanston and Mr Thom of Rothesay and reported to be “in a proper state of repair” and a perfectly secure condition.  These were no dilettantes.  James Smith of Deanston (1789-1850) was an agricultural engineer renowned for his work in deep soil drainage.  He invented the subsoil plough and with it converted the lands of Deanston from unproductive moorland to good agricultural land.  He also invented a turn-wrest plough and the web-chain harrow.   Robert Thom (1774-1847) was a Scottish civil engineer who worked upon major hydraulic projects on the Isle of Bute and Inverclyde.  He then created a larger system to supply water power to Greenock and the reservoir there is named after him — Loch Thom.  In the early 1800s, he designed the first water purification plant in Scotland.

Illus: Extract from the 1861/65 6ins Ordnance Survey Map showing the remains of the long Embankment for the Damhead (National Library of Scotland)

During the month of October 1839 several shocks of earthquakes were felt in various parts of the east of Scotland from Inverness to Bathgate.  Although not severe, they were sufficient to cause some alarm.  They occurred on the 7th, 10th, 13th, 14th, 16th, and 23rd days of the month.  Church bells in their belfries were set ringing by the vibrations, as were the servants’ bells in Thornhill House, Falkirk.  Persons seated in chairs could with difficulty retain their seats, and stone dykes or walls were thrown down.

The last of these quakes appears to have been the largest, measuring an estimated 4.8 on the Richter Scale.  A severe shock was felt at Denny and neighbourhood between eleven and twelve o’clock; the Rev, Mr Dempster, the minister of the parish, was awakened on the first tremor, and felt another distinctly immediately after.  Houses were damaged in Comrie and landslips occurred elsewhere.  In Falkirk the quake was felt at 10.30pm with an after-tremor around 2am.  

In the town, at the former hour, the houses shook, and culinary utensils struck one against another.  Some individuals were pitched from their seats, and others could with difficulty retain them.  Low sonorous mutterings were distinctly audible, and were thought to resemble the discharge of rounds of artillery, or remote thunder.  Camelon, a village situated west from Falkirk, and Laurieston, east of it, experienced similar throes.  The people were much frightened by its sudden effect, which shortly afterwards became insensible.  It is thirty years since a similar phenomenon occurred in this vicinity

(Caledonian Mercury 28 October 1839, 3).

Some eight hours after the earthquake the dam on the Earls Burn collapsed.  The Caledonian Mercury reported:

This, we believe is attributed to the Motus terrae with which we were visited… The embankment being ruptured, the efflux of its waters, like an impetuous mountain torrent, irresistibly swept off everything which opposed its course.  The inundation covers hundreds of acres, which have been cleared of any outstanding crops.  The river Carron, as it passes near this [Falkirk], was literally dense with turnips, hay, & c.  Some live stock, we learn, were found swimming in the torrent, together with agricultural implements, carts, and barrows.  It has wrought much devastation among the plantations on the banks of the river, by uprooting many trees, which the assuaging waters have left in our vicinity.  Bridges across the river, and mill-dams on its course, have been completely subverted.  We have not heard of the destruction of any human beings…”

(Caledonian Mercury 28 October 1839, 3).

The Scotsman’s correspondent in Denny was the Rev Mr Dempster.  He noted that fortunately there were few houses in the course of the torrent

but some milk-houses belonging to several farmers were swept away, and cheese, kits of butter, geese, ducks, and poultry were seen next morning floating below Denny.  Several damheads were also washed down, amongst others that at Garvel works, that at Tamaree mill, that at Mr Cairney’s printfield, and that of Mr Adams at Denovan.  Mr Duncan’s paper works are likewise considerably injured – the water at one time having risen to the height of eight feet in the machine-house.  A large wooden bridge across the Carron was likewise included in the general wreck.  A man and a woman with great exertion narrowly escaped the fury of the inundation

(Scotsman 30 October 1839, 3).

A longer description of the incident subsequently came to light and was published in 1925.  It provides more minute detail of the progress of the avalanche of water and so it worth repeating here:

Early on the morning of Thursday the 24th October 1839 about a third part of the embankment of the reservoir on the Earlsburn near Cringate, in the parish of St Ninians, gave way, pouring fourth an immense volume of water with fearful rapidity.  The first obstacle of any consequence that it met with was the bridge on the Fintry Road, near Muirmill, which was swept off instantaneously.  The next object of its fury was the farmhouse of Muirmill, then inhabited by Mr Alexander Muirhead.  This gentleman had just risen from bed, and was partially dressed, when, alarmed by an unusual noise, he looked out of a window, and saw a mountain of water, many feet in height, approaching his premises.  He immediately cried out to Mrs Muirhead to get out of bed and run for her life, for the reservoir was coming down.  She instantly threw herself out of bed, taking her youngest child in her arms, and, in the state she was, ran to the farm of Glendale.  Mr Muirhead, who took his other child, was running to a piece of rising ground to the westward when he recollected his money was in a “bit beuk” in the press.  He accordingly went back to the house, the water now reaching to his middle, got his “beuk,” and with difficulty got to a place of safety.  Several articles of value were carried off.  None of Mr Muirhead’s buildings were destroyed, except the milk house, the contents of which were swept away, and, what is very remarkable, the door of it and the byre stool were afterwards found at Planting Mill, a distance of eight miles.

The flood, after joining the Carron, swept away a considerable number of corn stooks and four ricks of meadow hay bear Carron Bridge, and then entered the house of Mr John Adam there.  The family were in bed, but they had time to get up and run undressed as they were.  It is said that some of Mr Adam’s blankets and most of the family’s “ilka day claes” were carried off.  After the flood entered the defile called Carron Glen, it carried of a quantity of wood from Mr Bain’s Black-mill and from Mr Glegg’s Dyewood Mill; it entered the paper mill belonging to Mr Duncan, spoiling a large quantity of paper.  It also swept away five damheads, three timber bridges, a quantity of cloth from Denovan bleachfield, which was recovered afterwards; and finally some turnips from a field belonging to Mrs McLaren of Dunipace Mills.”

The amount of damage done by the outbreak of the reservoir on the Earls Burn was estimated at several thousand pounds.  One field, of about half an acre in extent, has been so completely covered with stones, that the expense which would have been incurred by their removal would have been more than the value of the field.  One of the paper mills on the Carron had £400 of damage wrought upon it.  The large trout, with which the reservoir was filled, were left by the flood in the neighbouring fields in such immense quantities that the people in the vicinity were engaged for some time in carrying them away in baskets (Caledonian Mercury 11 November 1839, 4).  No human lives are known to have been lost.

A notable feature of the earthquake was the relatively large number of instances of ground slips and similar effects. It seems likely that the Earl’s Burn collapse was an accident waiting to happen to a poorly built six-metre high embankment dam waterlogged after two days of heavy rain – the earthquake triggered the dam burst, even if it was not the principal cause (Environment Agency 2011).  Analysis of more recent earthquakes has actually shown that damheads with a clay core cope quite well with earth tremors and it would seem that it was the narrowness of that at the Earlsburn Reservoir that was the problem.

Compensation had to be paid to the businesses affected by the torrent of water and over the next decade negotiations took place with them.  The greatest majority settled out of court but a handful took legal redress.

Now the Committee for the Reservoir had to raise the necessary money:

Glasgow 11th November 1841

Earlsburn Reservoir

       You are no doubt aware that in consequence of the breaking down of the embankments of this Reservoir, great damage was caused to the adjacent properties, the consequence of which was that a Reference was made to Mr Smith of Deanston in order to ascertain by whom and in what proportions this damage was to be repaid and the works repaired –

       When this agreement was entered into, many of the Tenants and others interested, were in circumstances which justified the belief, that they could afford to pay whatever loss was sustained – however from various causes, it is quite hopeless to look to some of them, and unless some relief is afforded by the great proprietors on the line, solvent Mill holders must make up the deficiency arising from the failure of these parties –

       Mr Smith upon the 28th September last, by an Interim Account ordered the sum of £4,000 to be levied from the various proprietors and tenants, and of this large sum, the following apportionments were made upon Mills situated upon your property,

1st Mill held by Mr Weir –£285144
2nd– –  by MessrsGray –285144
3rd– –  by Robt Forrest142172
4th – –  by J.G. Adam500
5th– –  by J. Williamson142172
6th Planting Mill by Mr Hay142172

       I hope that you will therefore give us some assistance in making up this assessment, and with that request I take the liberty of referring you to Mr Cairnie.                                                                   Wallace Jessop

(Forbes Papers 1271/7).

The Earlsburn Reservoir was eventually rebuilt by the Falkirk and Larbert Water Trust to supply drinking water for the urban conurbations to the east.  The new damhead was much more substantial.  Earth tremors continued to occur.  Thomas Johnstone of Hallhouse, Denny, recorded an earthquake at Comrie on 9 June 1865 and at Denny on the last sabbath of October 1889.


Dempster, J.1841New Statistical Account for Denny.
Environment Agency2011Lessons from historical dam incidents.
Reid, J1991‘The Diary of Thomas Johnstone of Hallhouse,’ Calatria 1, 57- 95.

G.B. Bailey, 2022