A digitally enhanced topography map - that shows the elevation data for a certain part of the earth, in addition to the man-made features - can help avoid water logging in cities.
Geologists have concluded this after a recent study over water logging problem in Lucknow. They were able to predict water logging in specific areas of the district and even suggested solutions for the problem.
"It is a natural phenomenon on the earth that some part of it is elevated and some are low lying. Water logging happens in places which are low lying," said Prof Vibhuti Rai, who conducted the study with help of a team of researchers.
Water logging, he said, happens in those low-lying areas that lack the natural ground water outlet channels such as a nallah or a rivulet.
Before the start of monsoon, the team of geologists identified on the topography map areas in Lucknow that are low lying. With the help of satellite imaging they confirmed the naturally occurring under ground water channels that these areas had but got covered with construction of colonies/houses.
"We identified Aliganj sector-E, Balaganj, Mahanagar and Jankipuran as the areas that were low-lying and had tributaries flowing in to the River Gomti sometime in the past," said Dr Rai.
When it rained, research scholars went to the identified spots to check whether there was any water logging or not. The assumptions turned out to be correct as all the low-lying areas marked in the map were water logged within few minutes of rains. Water remained on roads for over an hour on these spots.
The study aimed to find reasons behind problem of water logging that comes up in few specific areas within a few minutes of rains could find reasons.
"Almost all the low lying areas of the district had some under ground or surface water channel like a small tributary through which rain water used to drain out. At present all these tributaries have been covered up or blocked leaving water logging behind," said Prof Rai.
How the study was conducted
# Researchers first marked the low lying areas and located the under ground water channels (existing and defunct both) on the digitally enhanced topography map.
# On the basis of the markings, an assessment was made about water logging in the district. A team of scholars identified the areas where water logging should happen within a few minutes of rains.
# During rains, research teams were sent to different locations to take pictures of the situation after a few minutes of rains.
# Team members took photographs of the locations marked on the map. The pictures were taken during rain and it was ensured that the situation after fifteen or twenty minutes of rain should be captured.
# The result of the study was compiled by matching the assumptions and the fact-finding.