It means to regulate the water of a river by directing it into specific channel or channels which could be regulated through mini dams or by constructing Dhussi Bandhs.
There are three perennial rivers — Sutlej, Beas and Ravi, one non-perennial river, Ghaggar, in the state. Besides these rivers there are over 100 local rivulets, choes and khads, which run during monsoon, and fall into these main rivers. Some of them are Sakki/ Kiran Nallah, Sakki Nallah Diversion, Patti Nallah, Kasur Nallah, Hudiara Nallah, Chand Bhan Drain, Budha Nallah, Chand Bhan Diversion Drain, Jhabowali Choe, Swan, Siswan, Sagraon, Bhudki, Sirsa Nadis, Kali and Chiiti Bein (rivulets).
Only three perennial rivers are canalised by making dams. There is Bhakra dam on Sutlej, Pong dam on Beas and Ranjit Sagar dam on Ravi- and Dhussi Bandhs, which are though quite weak at several places and often get breached with a little heavy flow in rivers. Ghaggar river is partially canalised.
As for as local nadis, major nallahs are concerned, there is hardly any canalisation system for them and they flow to the brim during the monsoon creating havoc at several places of Punjab individually or after adding water to the major rivers.
On August 18-19, Punjab faced floods across around half dozen of its districts due to overflowing of the Sutlej river. And the major contribution in these floods was of local and seasonal non-canalised rivers, nadis, rivulets, nallahs, choes and khads which fall into Sutlej due to which its flow increased to 2.75 lakh cusecs on Sunday after heavy rain on Saturday. Though Bhakra dam, which is made on Sutlej river, is being blamed for releasing huge water on August 18 in river, but the matter of fact is that Bhakra had released only 55,000 cusecs in the river that day and remaining over two-lakh cusecs came from these local streams due to heavy rain in the catchment areas of these small streams.
Out of 57 small Nadis, Choes, Khads falling in Sutlej, the river got 58,750 cusecs from Sirsa river, 83,966 cusecs of Swan river, 14,778 cusecs of Budhki, 12,180 cusecs of Siswan, 13,800 cusecs of Sagrao near Ropar Headworks during that period. Now, this water from all these local rivers reduced to less then 10,000 cusecs in total.
Canalisation is needed to control such unregulated water which devastated state due to its uncontrolled flow. One local river Budhki is responsible for floods in Ropar, where its water spilled in several villages.