The Kohlis were the builders of the great tanks of the Bhandara
District. The most important of these are Nawegaon with an area of
five square miles and a circumference of seventeen, and Seoni, over
seven miles round, while smaller tanks are counted by thousands. Though
the largest are the work of the Kohlis, many of the others have been
constructed by the Panwars of this tract, who have also much aptitude
for irrigation. Built as they were without technical engineering
knowledge, the tanks form an enduring monument to the native ability
and industry of these enterprising cultivators. "Working," Mr. Danks
remarks, [531] "without instruments, unable even to take a level,
finding out their mistakes by the destruction of the works they had
built, ever repairing, reconstructing, altering, they have raised in
every village a testimony to their wisdom, their industry and their
perseverance." Although Nawegaon tank has a water area of seven square
miles, the combined length of the two artificial embankments is only
760 yards, and this demonstrates the great skill with which the site
has been selected. At some of the tanks men are stationed day and
night during the rainy season to see if the embankment is anywhere
weakened by the action of the water, and in that case to give the
alarm to the village by beating a drum. The Nawegaon tank is said to
have been built at the commencement of the eighteenth century by one
Kolu Patel Kohli. As might be expected, Kolu Patel has been deified
as Kolasur Deo, and his shrine is on one of the peaks surrounding the
tank. Seven other peaks are known as the Sat Bahini or 'Seven Sisters,'
and it is said that these deities assisted Kolu in building the tank,
by coming and working on the embankment at night when the labourers had
left. Some whitish-yellow stones on Kolasur's hill are said to be the
baskets of the Seven Sisters in which they carried earth. "The Kohli,"
Mr. Napier states, [532] "sacrifices all to his sugarcane, his one
ambition and his one extravagance being to build a large reservoir
which will contain water for the irrigation of his sugarcane during
the long, hot months." Each rates the other according to the size of
his tank and the strength of its embankment. Under the Gond kings a
man who built a tank received a grant of the fields lying below it
either free of revenue or on a very light assessment. Such grants
were known as Tukm, and were probably a considerable incentive to
tank-building. Unfortunately sugarcane, formerly a most profitable
crop, has been undersold by the canal- and tank-irrigated product of
northern India, and at present scarcely repays cultivation.