Read about Guru ka Tal at Agra. Guru ka Tal was meant to be a resorvoir for rainwater harvesting.

Guru-ka-Tal

Guru ka Tal was originally a reservoir meant to collect and conserve rainwater built in Agra, near Sikandra, during Jehangir's reign next to the Tomb of Itibar Khan Khwajasara in 1610. It had brick and rubble masonry embankments and retaining walls. People believe that Itibar Khan Khwajasara founded it and thus, his tomb was built on its eastern side. The spacious tank is square in shape and has a broad and long ramp paved with upright bricks and stone slabs called 'Khurra' on its southern side and a stepped ghat on either side. These walls boast of four double-storeyed octagonal towers. The upper storey of these towers are built in the contemporary architectural style of that time with beautiful octagonal chhatri with pillars and brackets and stone hooks on all sides probably meant for tent ropes. The red sandstone was used as the primary construction material of the ghat but it seems that originally cupolas of the chhatris appear were plastered or decorated with glazed tiles.

Originally there were twelve towers in all but only eight has survived the rigors of time. The reservoir had efficient inlets on western and northern sides of the tank, a dam on the southeastern corner of the reservoir and a canal, which was used to channel excess water into the river. The water of the reservoir was used for irrigation purposes during the dry season. The square red sandstone barahdari graces the terrace on the upper floor approachable through a broad red sandstone staircase on the southern side. Built on a four feet high platform, it has square chhatris in the four corners and sixteen pillars with beautifully carved capitals and brackets. The corner domes are spherical while those on sides are oblong in shape. The central dome gained dominance by size and height. Lately, however, the building has undergone complete renovation.