Chennai: Stormwater drains in two zones of the Chennai Corporation have been digitally mapped using the geographic information system (GIS). Just a few clicks on the digitised map will help officials find data on stormwater drains, which need to be managed well to reduce floods and improve public health in the area. The GIS mapping of stormwater drains in 18 wards in the Basin Bridge and Pulianthope zones was taken up as a project by Loyola College, the University of Madras and the Corporation. Using sketch maps, the project team physically verified the route of the stormwater drains, their outlets into a waterway and the missing links in the network. This was done using the global positioning system. Project's chief investigator S. Vincent, reader from the Department of Zoology in Loyola College and Tamil Nadu State Council for Science and Technology member secretary, said, "Mosquitoes spend their larval and pupal states in water. They can breed in stormwater drains. The digital database can be used to indicate vulnerable zones for various mosquito-borne diseases.' Data from the Health Department on the number of cases of vector-borne diseases have been incorporated into the digital map to find disease incidence trends.