View Point (Spotlight Weekly)

Changunarayan Hill is Cracking: Is Anyone Listening?

By HARI K. SHRESTHA

Cultural Heritage and Changunarayan Hill : UNECSO defines cultural heritage as the entire spirit of people in terms of values, action, works, institutions, monuments and sites. A designated cultural heritage site provides a reference to understand people’s value system. The cultural heritages also contribute to establishing and maintaining peace among people of various cultural backgrounds. As such, the value of such heritage is not limited to a single nation or people; it must be viewed as the global property. Recognizing the enormous cultural and architectural value of various structures in the Changunarayan Hill, UNESCO listed the hill and other structures, including Changunarayan temple, in the hill as a World Heritage Site in 1979. Located at an altitude of 1541 meters, on the western hillock of the Dolagiri ridge, one can get a magnificent view of Kathmandu valley from the temple area. At the foot of the 108 steps that lead down from the main gate of the temple lies the Shankha Daha. This temple is constructed in several concentric squares, with the innermost square containing the statue of a god. For the Hindus, the god inside the temple is Narayan and for the Buddhists it is Avalokiteshvara. So, this temple is a symbol of religious harmony.

The temple dates back to 325 A.D. King Haridutta Varma built the shrine along with the temple of Goddess Chhinnamasta Adidevi. Lichhavi King Manadeva erected a stone pillar, dated 464 A.D., with inscription written on it which is the base for considering Changunarayan temple as the oldest specimen of pagoda architecture in Kathmandu Valley. The present form of the outer visible superstructure of the temple was rebuilt in 1702 AD.

The temple site with its close surroundings has been declared as a protected Monument Zone by the government of Nepal under the provision of the Ancient Monument Preservation Act 1956. The preservation of this site from various types of disaster is a concern of all of us. The leaky roof of the temple was repaired recently, but the hill on which the temple stands is cracking, causing damage to temple and surrounding structures. The indications of increased landslide hazard in the Changunarayan hill are getting prominent. If these early warning signs are ignored for too long and timely precaution and preventative measures are not taken, then it can be too late to save the World Heritage Site.

Warning Signs in and around Temple Premises

The Changunarayan temple is a masonry structure. The outer brick wall of the temple showed signs of twisting and tilting. The wall tilting is one of the early indicators of possible beginning of landslides. Various other parts of the temple also exhibit tilting. The wall of the temple is coming apart

The Changunarayan hill is one of the few sites in Nepal listed under the World Cultural Heritage Site.

The hill houses the most ancient temple of Kathmandu Valley. There are numerous land cracks at various locations around the hill and structural cracks in the temple itself, providing early warnings of an impending landslide that can have catastrophic and irreversible effect on this site. No one seems to be listening to the early warnings and no agency seems to be responsible for the protection of the hill. Sand mining is accelerating at the base of Changunarayan hill and at Manohara River. The old ways of flood irrigation in agricultural fields is continuing. Trees are falling and new constructions are going on in the hill without paying any heed to the warning signs. It is time to listen, learn and act accordingly.

Bricks in the upper floor of the temple have separated from each other at the mortar joints. The wooden frames of some of the doors of Changunarayan temple have tilted, indicating possible beginning of landslide. The base of at least one main door frame has been lifted in one side. Some wooden frames have protruded from its base. If no preventative actions are taken in time, the damages will progress further.

The bulging of stone steps, which is the main access to the temple from the west side, is a clear indication of soil movement in the Changunarayan hill. The land bulging has collapsed part of the walls on the sides of the stone steps and displaced the stone slabs. The land bulging is a clear sign of weakening of hill, in terms of its slope stability. Structural cracks can be seen on the pilgrim rest houses, other buildings around the temple, and stone pavements, which are other signs of initiation of landslide in Changunarayan hill. Pavement cracks result when the soil underneath the pavement begins to subside.

Warning Signs in Changunarayan Hill

The weakening of the Changunarayan hill is exhibited by various small and medium sized landslides, tension cracks in soil, ditch formations etc. at various locations of the hills. Most of the evidences were noted around places where some type of construction, such as surface drain, water supply pipe line or foot-path have been made or around the part of the hill with human settlement.

There are some ancient structures about 50 meters above the top of this landslide site. This landslide occurred probably almost a decade ago. No protective measures have yet been taken for this landslide site. The pine trees seen in the eastern side of the landslide were planted recently. With passing of every monsoon season the size of this landslide is gradually getting bigger.

The evidences of land subsidence (tension cracks) can be found at various locations in Changunarayan hill. There is one such location at the south-west part of the hill. These tension cracks in the land are some of the clear evidences of impending catastrophic event in Changunarayan hill.

Possible Reason for cracks in the hill and temple

The causes of the early warnings of landslide potential at Changunarayan hills can be many. Only a detailed study will pin point the exact causes. However, some of the possible reasons are apparent. There are various settlements and agricultural fields on top of relict landslides in Changunarayan hill. Various developmental activities are carried out around human settlement without understanding the geology of the area, which weakens the hill. High water demanding agricultural activities also makes the hill sides more vulnerable as water seeps down and creates a favorable condition for landslides.

In Changunarayan hill, the tree density has severely reduced during the past decade with consequent erosion of the slopes. Much of the forests have disappeared and hillside erosion is evident. The rate of sand mining from the bases of the hills and from the river that runs through the base of the hill is accelerating. Under the Local Self Governance Act-1998, the local authority (Village Development Committee) has issued licenses to contractors for sand mining from the bases of Changunarayan hill to enhance revenue collection. The river sides are also cut to increase sand yield. Illegal sand mining is also going on at rapid rate from Manohara River.

The river bed of Manohara River has declined causing collapses of river banks. A bridge over Manohara River at Sano Thimi has collapsed and a new bridge was recently constructed. This action of sand mining is exacerbating the fragile slope stability problem of the hill. New constructions in the Changunarayan hill is going on with very little regard for the effects on slope stability measures and on cultural integrity of the World Heritage site itself. In fact, UNESCO has recently warned Nepal to take out Kathmandu Valley from the list of World Heritage site if new constructions incompatible with UNESCO criteria around the heritage sites are not stopped. Natural causes such as weak geological formation and intense rainfall can also make a hill more prone to landslide. As per the geological map prepared by Department of Mining and Geology, Changunarayan hill consists of relatively strong formation in the upper and eastern part of the hill. The lower part of the hill in the north, west and south is composed of loose unconsolidated alluvial deposits consisting mostly of sandy silt and sandy clay.

Layers of sand, silt and clay can be seen in differing succession and composition. The relatively weak and erosion prone formation at the base of the hill indicates the sensitivity of the hill towards activities that may initiate soil erosion. Changunarayan hill experiences occasional intense rainfall in the monsoon season. The high intensity rainfall dislodges soil particles and creates ditches. The ditches turn into gullies which transport more soil particles downhill. This process eventually leads to landslide event.

Kathmandu Valley is situated in an earthquake prone area. The earthquake events loosen contact between soil particles and reduce soil strength which can trigger landslides. The silty sand, as found at the bottom of Changunarayan hill, normally tends to have high conductivity value which facilitates rapid infiltration of rain water. The infiltrated water raises water table elevation and pore water pressure. The rise in pore water pressure can cause landslide by reducing soil shear resistance.

Time to Listen

Nature is ringing enough warning bells to awaken us and to take note of the impending disaster in a very important cultural heritage of Nepal. It is time to listen, learn and act properly in time before it is too late.

(The writer is associated with Nepal Engineering College and is currently a Doctoral Candidate at Ehime University, Japan)

The Changunarayan hill is one of the few sites in Nepal listed under the World Cultural Heritage Site. The hill houses the most ancient temple of Kathmandu Valley. There are numerous land cracks at various locations around the hill and structural cracks in the temple itself, providing early warnings of an impending landslide that can have catastrophic and irreversible effect on this site. No one seems to be listening to the early warnings and no agency seems to be responsible for the protection of the hill. Sand mining is accelerating at the base of Changunarayan hill and at Manohara River. The old ways of flood irrigation in agricultural fields is continuing. Trees are falling and new constructions are going on in the hill without paying any heed to the warning signs. It is time to listen, learn and act accordingly.