Not many would believe, but the expert committee constituted 04 days after Sher-ka-Danda landslide carried out detailed field investigations, established the causes of slope instability, and recommended not only elaborate mitigation measures but also suitable implementation mechanism in just 19 days, and these were actually implemented on ground in less than 02 years.
The Lake City
Though discovered in 1823 by G.W. Traill, Commissioner of Kumaun and Garhwal, habitation in the area around Naini lake started in 1841 with P. Barron constructing Pilgrim Lodge.
The area however developed at a fast pace and soon became a favourite amongst Europeans. More than weather and connectivity, being a safe heaven during the First War of Indian Independence in 1857 induced Europeans to settle around Nainital.
151 was a big number for a city just 40 years old.
Death and destruction with 151 persons including 43 Europeans killed in the Sher-ka-Danda landslide of September 18, 1880 made everyone suspecious of the safety of life and property in the lake city that was growing at a fast pace.
The Committee
Realising the concern of the people, and to rule out possibility of recurrence of Sher-ka-Danda like incidence in future a Committee was constituted 04 days after the landslide on September 22, 1880 under the Chairmanship of Commissioner Kumaun Lt. Gen. Sir Henry Ramsay to suggest measures for ensuring safety and security of life and property in and around the lake city.
The Committee was quick to realise the importance of the issue, and acted promptly. The entire area around the lake was surveyed to conclusively establish the causes of the landslide, and accordingly suggest remedial measures. The report was finalized in just 19 days and submitted on October 11, 1880.
So meticulous and detailed were the investigations carried out by the Committee that it could conclusively put forth that there existed no danger in the areas to the west of Cheena Lodge and east of Melville Hall.
Causes of Instability
The Committee attributed the landslide to the presence of highly incompetent rock mass in the destabilised area, and took cognisance of its being saturated with water due to continuous rainfall received before the incidence.
The Committee mapped and analysed not only the geological set up, but also landuse and geomorphic changes in the area, and correlated these with possible causative factors to gather a holistic understanding of the process resulting in the devastation. Based on the investigations the Committee concluded that reckless slope modification undertaken for various anthropogenic purposes during the previous decade had augmented groundwater infiltration that facilitated the landslide.
The Committee accordingly concluded that heavy rain operated along the hillside in three different ways:
(i) Most portion of the hill slope was formerly protected by dense cover of grass, shrubs and trees that ensured downslope dissipation of surface flow in thin sheets. Modification of the hill slope for accommodating roads, houses, gardens, and tennis courts however provided flat surfaces on which large volume of water collected during spells of heavy rains.
The Committee observed that the water so collected was recklessly directed towards the nearest ravine that resulted in entire surface runoff of the hill slope getting concentrated in certain ravines that in their natural state were not fit to receive it. The rushing down water continuously eroded earth and shale along the banks of these ravines, causing general settlement of their upper surface.
(ii) The rainwater collecting over flat surfaces on the hill slope had an opportunity of percolating into the surface, and flowing downslope along underground channels through loose earth and shale. During spells of heavy rains the underground channels were exposed to severe action by the water flowing under high hydrostatic head.
Where these channels passed through rocks with unfavourably disposed inclined stratification, water facilitated upper strata to slip along the lower. Where these passed through earth and shale, water scoured the channel, thereby undermining the whole superincumbent mass, and causing landslip sooner or later.
(iii) Underground water saturated the whole hillside where it could not escape, and the Committee perceived this as being the most dangerous state of affairs, as even small undercutting or slipping in a neighbouring ravine could then instantaneously initiate an avalanche of mud and shingle.
Water was identified as being the prime mover in this kind of instability resulting in downslope movement of a heterogeneous mass of mud and stones whose power of progression was regulated partly by the slope over which it moved, and partly by the amount of fluidity of the materials composing it. Large area in the downslope direction was adversely affected by such slides due to the fluidity of the landslide mass.
The Committee took note of large volume of water pouring out for quite some time along the scarp of the Sher-ka-Danda landslide from the underground reserves and concluded this as being the main cause of the landslide of September 18, 1880 that caused widespread sorrow and distress.
The Recommendations
After fully understanding the process and causative factors of the landslide the Committee made comprehensive recommendations for ensuring safety of life and property in the lake city, and submitted the same on October 11, 1880.
Salient features of the mitigation measures recommended by the Committee are summarised below.
(i) All major ravines be revetted at intervals by strong cross-walls, curved in plan, with well-guarded flanks or wing walls built into the rocks on either side. Considerable batter be ensured on the face of these walls, with courses laid at right angles to the batter.
(ii) All ravines be lined where necessary with side walls, and strongly paved flooring laid in lime mortar.
(iii) The channels be made large enough to carry at least double the maximum flood volume which has been known to flow down these up to date.
(iv) The cracks and fissures in the hillside be carefully searched for, dug out as far as these can be traced, and refilled with well-rammed clay.
(v) The platform around every house be covered with a six-inch layer of well-rammed clay, or other impervious material. In case of destroyed or abandoned house, this be done at public expense.
(vi) Gardens and cultivated terraces be absolutely prohibited. Ones that exist be covered with clay and turfed immediately.
(vii) Existing lawn tennis grounds be permitted only on the condition that adequate precautions are taken to prevent the percolation of water from these into the hillside.
(viii) Construction of houses or other buildings, quarrying of stone, and excavation of terraces or platforms for any purpose whatever, be absolutely prohibited in the southern slope of the Sher–ka–Danda hill.
(ix) Special care be taken to prevent erosion from household drainage. A gutter be ensured under the eaves in every house together with a catch-water drain around its base. The water from these be carried in a masonry channel to the most suitable ravine, in which provision be made for its reception.
(x) All bulged or cracked retaining walls be restored by house proprietors, and walls be built where these do not exist and where their absence has caused or may hereafter cause slips.
(xi) In areas with tendency to slip, the slope immediately above the retaining wall be modified to an angle of 40o.
(xii) Where necessary improvements be carried out on private property, with cost thereof to be charged from the house or land owner.
(xiii) All steep slopes be turfed, and planted.
(xix) Cutting of grass and grazing on the southern slopes of Sher–ka–Danda and Cheena be strictly prohibited.
(xv) The maintenance of all watercourses in ravines, as also all roadside drains be the responsibility of the Civil Officer Incharge of the station.
(xvi) An Inspector of buildings and drains be appointed to assist the Civil Officer Incharge.
(xvii) Special gang be employed during the monsoon period to keep the drains obstruction free and fully functional, and to immediately repair damages, if any.
(xviii) All operations affecting stability of the hill slope, and safety of the station be carried out by the orders of the Civil Officer Incharge, through the agency of the Inspector.
(xix) Private individuals not be allowed to construct any drain, wall, or building without written permission of the Civil Officer Incharge, and supervision of the Inspector.
(xx) The Civil Officer Incharge be entrusted power to carry out the above, and other measures deemed necessary for the safety of the station without reference to the Municipal Committee.
(xxi) All financial resources earmarked by the Government or the Municipality for the maintenance and improvement of drains and roads be placed at the disposal of the Civil Officer Incharge, to be expended by him, without reference to the Municipality, in a regular and systematic manner, with the advice of the Superintending Engineer of the Provincial Circle, when necessary.
The Committee hoped that the implementation of these measures would protect the lake city from further damage. It however stressed upon prompt, careful, and complete execution, particularly in the more damaged areas, before the next monsoon period.
As is clear from the above point (xv) – (xxi) the Committee not only suggested mitigation measures but also apparatus and mechanism for implementing and maintaining the same.
The Implementation
Constituted on September 22, 1880 the Ramsay Committee submitted its report on October 11, 1880. This report did not remain dormant in the almirahs of the administrators, and the matter of restoring stability of the hill slopes around Nainital and ensuring safety and security human lives in the town was taken seriously by the British Raj.
Forbes Committee of 1882 observed in its report that most remedial measures suggested by the Ramsay Committee of 1880 were carried out, and it considered the portion of the Sher–ka–Danda safer than it ever was.
Hillside Safety Committee
A number of committees were constituted at regular intervals to investigate stability of the hill slopes around Nainital. These include Henslowe Committee of 1883, Corbett Committee of 1895, Beresford Committee of 1895, Engineers Committee of 1899, Berthoud Committee of 1907, Dobbs Committee of 1927 and Coulson Committee of 1937.
Apart from the above the slopes around Nainital were regularly studied and investigated by various geologists – Mathews in 1888, Richard Dixon Oldham in 1889 and 1895, Henslowe in 1889, Holme in 1890, Charles Stewart Middlemiss in 1890 and 1898, Carl Ludolf Griesbach in 1895, Holland in 1897, Edgar in 1925, and Coulson in 1928.
Coulson Committee of 1937 recommended banning construction of any kind on Sher–ka–Danda hill.
Cousin Committee at the same time recommended constitution of a committees having at least one geologist as member at regular intervals of five years to review the efficacy of various remedial measures implemented for the safety of the hill slopes. In accordance with this the practice of constituting Hillside Safety Committees continues to this day.
Recently read a report on landslides in Nainital in Hindustan Times. It attributes the landslides to some kind of tectonic movements.
Did the Ramsay Committee observe this aspect as well?
Congratulations for an excellent compilation with graphic details.
Hope it keeps the memories of hard and fruitful work done during that time despite constraints of various sort afresh in the memories of the masses, and they demand more productive and timely output from the disaster managers and other technocrats of our times,