Recent landslide incidences in and around Nainital are attributed to disruption of the age old rainwater drainage system designed for maintaining the pore water pressure within threshold limits, and could result in a major catastrophe if due attention is not paid towards maintaining efficiency and effectiveness of this system.
1880 में हुवे शेर का डांडा भू-स्खलन के कारणों की गहन विवेचना के बाद नैनीताल शहर को सुरक्षित बनाने के लिये की गयी संस्तुतियों के क्रम में अस्तित्व में आया नालो का तंत्र आज मलबा निस्तारण के लिये उपयोग में लाया जा रहा है और साथ ही अतिक्रमण व शहरीकरण की मार झेल रहा है।
इससे जहाँ एक ओर नैनी झील छिछली हो रही है वही दूसरी ओर वर्षा के पानी के अत्यधिक मात्रा में सतह के नीचे रिसाव होने के कारण झील के चारो ओर की पहाड़ियों की संवेदनशीलता भू-स्खलन के प्रति बढ़ रही है और यह निश्चित ही किसी बड़ी आपदा की पूर्वसूचना हो सकती है।
अतः आवश्यक है की समय रहते इस तंत्र को सुदृढ़ बनाने पर अपेक्षित ध्यान दिया जाये।
Conceptualisation
Ramsay Committee constituted after the landslide of September 18, 1880 to review the safety of life and property in the lake city held excess infiltration of water, consequent built up of pore water pressure, and lubrication along fissile planes as being responsible for the Sher-ka-Danda landslide.
Having appreciated the importance of quick and efficient disposal of rainwater from the vulnerable slopes around the Naini lake, the Ramsay Committee recommended amongst other measures, provision of smooth and quick drainage of rainwater from the hill slopes.
In accordance with the Ramsay Committee recommendations six main ravines on the slopes around the Naini lake were lined with masonry, and revetted in the first stage. With the passage of time a number of other drains were planned, and constructed on both eastern and western slopes to drain the rainwater into the lake.
The drainage systems
For the purpose of record keeping as also for efficient monitoring, the drainage system of Nainital was divided into compartments or systems and detailed inventory of each compartment was prepared.
Sher-ka-Danda system
This system included entire Sher–ka–Danda hill from North Bridle Road and Upper Kaladhungi Road to the ridge lying between drain No. 23 on the west and Cantonment on the east excluding the branches of drain No. 23 and tributaries of Bara Nala from the drains lying in this area.
This system thus comprised of all the drains of Sher–ka–Danda from lake bridge to Upper Bazar. In 1932 this system had 35 main drains, up to 2.1 m wide and 1.2 m deep, with the network totaling 7392 m.
Bara Nala system
This system included whole of the area from the lake westwards, lying between Lower Kaladhungi Road and the Cheena ridge up to drain No. 23, the eastern boundary being formed by drain No. 23 up to where it crossed the Upper Kaladhungi Road, from where the boundary ran along the latter road to the lake.
This system thus comprised the drains of Cheena, Sukhatal and Ayarpatha hills not discharging directly into the lake. In 1932 this system was 3074 m long with upto 4.6 m wide and 2.7 m deep drains.
Ayarpatha system
This system included the whole of Ayarpatha hill above South Mall and Lower Kaladhungi Road up to the ridge bounded on the west by Prospect Road and on the south and east by Donaldabad Road, Ramsay Road, Fairy Hall drain up to the Cart Road and Cart Road up to the lake.
This system thus comprised the drains of Ayarpatha that dischargd into the lake. In 1932 total length of the drainage network in this system was 2773 m with the drains up to 1 m wide and 0.6 m deep.
System beyond the lake basin
It included the whole area to the south and east of the land formed by Donaldabad Road up to the junction with Ramsay Road, Ramsay Road up to the commencement of Fairy Hall drain, Fairy Hall drain to the crossing of the Cart Road, Cart Road up to Tallital Post Office, thence the western, southern and eastern boundaries being the Manora spur, the Bareilly – Ranikhet cart road and the Kaladhungi spur. The area of the Cantonment was also included in this system.
Besides Balia ravine and its branches this system comprised Fairy, Bulls Head drain, Police Line drain and all their branches that discharged into the ravine and beyond the lake basin. In 1932 total length of the drainage network in this system was 5910 m with drains up to 1 m wide and 1 m deep.
Regular maintenance
The drainage system conceived by the Ramsay Committee aimed at speedy and efficient drainage of the hillsides, and was designed with great care.
The British Raj officials considered it necessary to ensure upkeep of the Municipal and Provincial roads, and the roadside drains in the settlement as the former contributed appreciable share to the drainage and the latter carried, in addition to the drainage from the roads, a portion of the hillside drainage as well.
The bearing of roads on the stability of the hill slopes was thus clearly understood.
As the efficiency of the drainage system had a direct bearing on the stability of the hill slopes, adequate measures were put in place for its proper and regular maintenance so as to ensure peak performance at all times.
Provision of silt traps and desiltation chambers was ensured in all the drains around the lake and adequate arrangements were also put in place for their regular maintenance and upkeep. In accordance with the recommendations of Ramsay Committee a gang was employed during the monsoon period to maintain and repair the drains.
Besides the drainage works including adits, it was perceived necessary to put in place protective works such as walls, barriers, and terraces so as to facilitate stabilisation of the hill slope.
Detailed guidelines were laid down for regular inspection of the roads and drains and for ensuring their regular upkeep and these were issued through Government Orders. The compliance of these was included in the annual reports.
Drains in disdain
Not appreciating the importance of the drainage network so meticulously planned and executed, due importance has not been accorded lately to its regular upkeep and maintenance.
Many silt traps and desiltation chambers have thus become non-functional while the retaining walls of many drains have been damaged. At many places the drains are being utilised for dumping the excavated material while at others the drains are being encroached upon for construction works. Enhanced siltation of the lake in recent times can clearly be attributed to this, and if not checked the existence of the lake is sure to be jeopardised.
Present condition of the drainage system of Nainital makes it clear that the carrying capacity of the drainage network has been severely compromised, and this could be one of the reasons of recent landslides in Nainital. If recent landslides along Balia ravine are associated with abandoning Balia Nala hydroelectric power (HEP) project, the landslides around the lake in recent times are attributed to non-maintenance of the drainage network.
It needs to be appreciated that reduced capacity and efficiency of the drainage network is to augment groundwater infiltration and built up of pore water pressure that resulted in the catastrophe of 1880, and small slides around the lake in recent times could be a warning signal of a major devastation.
It is therefore recommended that the responsibility of maintaining the drainage works as also roads in and around Nainital be entrusted to an agency with regular budgetary provision for repair and upkeep to ensure safety and security of life and property in the lake city.
SIR What are you really doing there in Uttarakhand where no one cares for what you have all through been doing. You should be part of a larger platform from where your voice is heard and acted upon. May be NDMA …. But then … you require a messiah to pull you through for on your own … you would be lingering around in Uttarakhand. Hope some spotter gets sight of you.
Really purposeful article that is hard to come by these days where most articles are engrossed with individual, event and achievements.
An important message put forth by Dr. Rautela. If we wish Nainital to thrive and prosper we have to ensure that it’s free of disasters. Manage the drains and keep the risk at bay – message for LDA.
Great sir. Keep going.
An enlightening article indeed. Hope the civic authorities of Nainital take note of the concerns.
Your articles inspire us sir.
Great message sir
Great message. Hope the residents of Nainital wake up before it’s too late.
These issues are often not touched upon. Hope Dr. Rautela with his clout in administration, brings forth a rule that heavily penalises ones abusing the nalas of Nainital that I realise were designed and put in place for the safety and security of the people of Nainital. We really need to respect these and avoid abusing them.
Thanks RISKAVOIDER. Hope the risk looming large over Nainital is avoided?
Thanks RPMMF for raising this important issue.
If we the residents of Nainital do not pay due attention towards the upkeep of these waterways and ensure that these are not littered, the fate of the Naini lake and the town is doomed. Hope such articles help bring forth awareness on issues that affect us all.
All the litter that flows down these drains ultimately reaches the lake and presents an ugly face of the city before tourists
Hope we could reduce the waste dumped in these drains.
Such information would facilitate behavioural change amongst masses and they would treat these waterways with respect.
Really informative. Despite having lived all through in Nainital I never happened to appreciate the importance of all these drains. Thanks and hope that the people of Nainital would become more responsible through such information.
Since a scientist (Dr Piyush Rautela) is heading the department, I am sure the scientific approach will save the city of Nainital.