How Clean is the Canal in this Part of Colombo?

An RTI application was sent to the Sri Lanka Land Reclamation and Development Corporation (SLLRDC) in early December 2019 regarding the canal in Dematagoda and its cleanliness. This was due to the fact that the canal had very dark-colored, unclean looking water. The questions in the Right to Information application mainly focused on the measures taken by the SLLRDC to ascertain that this water body did not cause harm to life or the surrounding environment.

The application questioned the measures that had been taken to ensure that this canal’s water was clean and did not pose a health risk to those in the vicinity or pose any risk to the environment and biodiversity. In addition, the information requestor also asked about the measures that had been taken to improve this canal’s aesthetic value.

The Sri Lanka Land Development Corporation included in its reply the fact that the degradation of water quality in the Dematagoda canal is mostly due to the area’s dwellers’ ad-hoc activities such as garbage dumping and sewerage discharge activities. The environment and biodiversity may be adversely affected because of such activities and also because of unauthorized encroachments along with the canal reservation.

With regard to improving the canal’s aesthetic value, the reply stated that the Sri Lanka Land Development Corporation was responsible for carrying out the daily maintenance activities in the Dematagoda canal such as surface cleaning, dredging, cleaning of catch pits and side drains, and the maintenance of the reservation area and the canal bank.

In addition to the above information, the SLLDC also provided graphical data pertaining to the differing levels of ammonia, nitrates, phosphates, dissolved oxygen, etc. from the years 2016, 2017, and 2018. Some points that can be easily noted by studying these bar charts are that turbidity, ammonia (NH₃), and dissolved oxygen (D.O.) levels in the canal were notably higher in 2016 than they were in 2017 or 2018. At the same time, the overall salinity level was highest in 2018. (For all the graphical information provided, please see the graphs accompanying this article. These are exactly as have been provided by the public authority.)