‘Badi Baoli’ or large step-well is a functional step well collecting rain water from a large catchment area as well as linked to a network of aqueducts running throughout the site. First built in the 16th century, major additions and alterations were carried out here in the 19th century when the arcaded corridor and passageway running throughout the lower floor as well as stairways were built, significantly raising the level of masonry of the structure.
A. Analysis of Collapse
Though the Badi Baoli had small portions of collapse even during the architectural documentation carried out in 2011, it was the most structurally well preserved of all the step-wells found within the complex.
However, with the Wakf Tribunal’s orders preventing the commencement of conservation works following the MoU on 9 January 2013, the Badi Baoli suffered significant and repeated collapse during the heavy monsoon rains of 2013. Conservation works could only commence in November 2013 following the Wakf Tribunal’s permission for the same.
- A study of archival material (Above) revealed that the ‘Badi Baoli’ was only a tank until the 19th century when the structure was altered and the arcade on the upper level provided where only sloping ground existed originally.
- The slope analysis revealed that large portions of the site were draining into the Badi Baoli and the 19th century arcade and associated masonry had interrupted natural drainage lines.
- Recent alterations of the levels of the setting had further created collection points for large quantities of rainwater which was causing severe pressure on the masonry.
- From the onset of the conservation effort it was evident that in order to ensure long term structural stability alternate systems of water drainage into the Badi Baoli needed to be established.
B. A study of archival material (Above) revealed that the ‘Badi Baoli’ was only a tank until the 19th century when the structure was altered and the arcade on the upper level provided where only sloping ground existed originally. • The slope analysis reve
- At the onset, 2, 00, 00,000 litres of water was required to be pumped out and fed into other adjoining step-wells. Following the initial removal, the pumping out required to be continuous to allow the well to dry out.
- Over 450 cubic meters of stone debris and silt was lifted to the ground level from the 21 m deep bed of the Baoli.
- All stone thus lifted was cleaned of mortar for re-use in the re-construction of the collapsed masonry.
- Over 4000 man days of work was required to clear the Baoli of collapsed masonry, existing silt and other accumulations.
C. Re-construction of the Collapsed Wall
- With the bedrock at the base of the Baoli having disintegrated to a considerable extent, it was required to build a masonry wall from much deeper than it had previously existed.
- This also required to serve as a retaining wall of the bed-rock and earth as well as support the huge quantum of masonry and was thus proposed to be built as a buttress.
- The masonry required a 1.5 meter wide and 0.5 meter thick RCC raft foundation, 11 meters long at a depth of 22 meters from the ground level.
- The bottom half of the stone masonry, built in lime mortar, was built as a buttress also as not enough width was available due to portions of bed-rock still standing.
- The stone masonry employed stones measuring up to 2 m in length to key into the masonry at several places.
- Up till September 2014 over 600 cubic meters of masonry wall had been built up.
- Collapsed steps on the North West corner of the wall were also re-instated. 10 new pieces of dressed granite stones of the original size 2.5 meters length were prepared to complete the stairs.
- Work was temporarily stopped in September to allow the lime mortar in the masonry to set over the winter period.
- In summer 2015, the reconstruction of the arches, corridor and the roof would commence.
- Removal of cement pointing from the other three sides of the Baoli would be taken up and followed with lime mortar grouting and pointing.
- The reconstruction of the solid stone masonry wall in lime mortar within a very short duration of time was necessary to prevent further collapse and deterioration of the Badi Baoli, three sides of which were still standing
D. Channelization of the Surface Water
Since the Badi Baoli served as a natural catchment for rainwater from a large area of the Qutb Shahi Heritage Park, it was necessary to make an appropriate arrangement to allow the water into the Baoli. Previous evidence of channelization of rainwater was also found on the ground. However, as this directed large quantities of water down the steps, it was considered to be leading to deterioration and was considered inappropriate.
- An alternate channel was built to the west of the masonry wall of the Badi Baoli with an exaggerated slope up to the corridor level following which an open channel was built to direct water into the Baoli.
- The channel was built as a homogeneous structure with the retaining wall so as to withstand the pressure. The channel floor was made of 8” thick lime concrete finished on the 3 sides so as to avoid percolation.
- A manhole was made beneath the corridor to allow easy maintenance.
- From the manhole onwards, the open channel has a granite base slab.
- The creation of an alternate channel has ensured that enormous water pressure on the retaining wall has been mostly negated thus allowing long term preservation. During 2014, over 1 million litres of water has been collected from a rain of 77.5 cms.