Emperor Shahjahan (1627-58 AD) first shifted the city from the Aravalli
hills towards the plains of the Yamuna. But he made sufficient arrangements
to meet the water needs of the new palace, the army, and the common
people. His system of Shahjahani canals and dighis was probably the
best creation of the time.
Shahjahan ordered Ali Mardan Khan and his Persian artisans to bring
the waters of the Yamuna to the city and to his palace. Ali Mardan
Khan not only brought Yamuna waters to the palace, but also linked
this canal with another from Sirmaur hills, presently located on the
Delhi border near Najafgarh. The new canal, Ali Mardan canal, channelled
the waters of the Sahibi river basin to merge into the old canal.
In the main city, the canal charged dighis and wells. A dighi was
a square or circular reservoir of about 0.38 m by 0.38 m with steps
to enter. Each dighi had its own sluice gates. People were not allowed
to bathe or wash clothes on the steps of the dighi. However, one
was free to take water for personal use. People generally hired
a kahar or a mashki to draw water from the dighis. Most of the houses
had either their own wells or had smaller dighis on their premises.
In the event of canal waters not reaching the town and the dighis
consequently running dry, wells were the main source of water. Some
of the major wells were Indara kuan near the present Jubilee cinema,
Pahar-wala-kuan near Gali-pahar-wali, and Chah Rahat near Chhipiwara
(feeding water to the Jama Masjid).
In 1843, Shahjahanabad had 607 wells, of which 52 provided sweetwater.
Today 80 per cent of the wells are closed because the water is contaminated
by the sewer system.
Besides tanks, sultans and their nobles built and maintained many
baolis (stepwells). These baolis were secular structures from which
everyone could draw water. Gandak-ki-baoli (so named because its water
has gandak or sulphur) was built during the reign of Sultan Iltutmish.
The water of this beautiful rock-hewn baoli is still used for washing
and bathing. Adjacent to this, there are the ruins of other baolis
like Rajon-ki-baoli, a baoli in the Dargah of Kaki Saheb, and a caved
baoli behind Mahavir Sthal. During this period baolis were built in
other parts of the city too.
Muhammad-bin-Tughlaq (1325-51 AD) inherited Delhi with three competing
habitations, and added a fourth one to it - Jahanpanah - which means
the shelter of the world. The Satpula (meaning seven spans) was
built to regulate water supply for irrigating the area falling outside
the city. Built across the southern wall of Jahanpanah, it is a
dam towering 64.96 m above ground level. Its seven principal spans
were sluices that controlled the water in an artificial lake.)