A stepped-well (Baoli, Vav, Vapi) is generally a rectangular structure containing a draw well, constructed below the ground level. It is approached by a long stepped corridor which leads from the ground level to the water of the well. Building stepped-wells especially in arid regions was a common practice in the Indian subcontinent. Mostly placed on travel routes, these not only served to quench thirst of the travellers, the space created several levels below the surface of these elaborate wells provided cool resting places. Besides the well these used to have additional tanks for bathing and washing purposes. The Center for Art and Archaeology's image collection of stepped-wells include documentation from Rajasthan, Gujarat, Karnataka, Delhi, Haryana, Punjab and Madhya Pradesh.
The Helical stepwell is situated at the foot of a hill near the town of Pavagadh. It is altogether a small monument, measuring in all not more than 19 metres. It consists mainly of the shaft of the well, and a short entrance staircase which leads into a spiral stairway. This spiral stairway is attached to the wall of the well and descends downwards like the ‘coils of a snake’. The idea of circumambulation is expressed in the spiral stairway. This stepwell reflects the very early stage of stepwell architecture.
Reference: Jain-Neubauer, Jutta. The Stepwells of Gujarat: In Art-historical Perspective, 2003.