Unplanned urbanisation led to water crisis

Unplanned urbanisation, if unchecked, will have a negative impact on the quality of life, experts on land use and land change have warned.

They have also stressed on the dangers of further loss of agricultural land, forest land as well as lakes due to urbanisation.

An independent study on urbanisation in Mangaluru was published in the Indian Society of Geomatics’ Journal of Geomatics recently.

The study reveals that, within 20 years from 1997, the built-up area (settlement) has increased by 270% in the city. The expanse of water bodies in Mangaluru – comprising of lakes and ponds (open source) – has drastically reduced by 70% in these years. Land under cultivation (1%) and mixed forest (16.13%) too have seen a decline over the years, the study has mentioned.

Three zones

“For the study, Mangaluru taluk was divided into three zones, based on geographical division of the rivers,” informed Sanjith S Anchan, the primary author of the published study.

“The area above River Gurupura was identified as the northern zone. The central zone included the land between Gurupura and Nethravathi rivers. The land beyond River Nethravathi was classified as the southern zone,” Anchan added.

The team used remote sensing and the Geographical Information System (GIS) technology to make to make an accurate analysis.

“If the northern and central zones had witnessed drastic increase in built-up area. The southern zone did not witness any increase as it had a few universities and villages. The water bodies in the northern and southern zones had reduced drastically as both wetlands, grasslands and open lakes – which are misunderstood as wastelands – had been converted into sites and commercial establishments. The central zone, comparatively, had not many water bodies. The drastic increase in built-up area is due to intensive urban growth and industrial revolution,” explained Anchan.

Heat islands

Dr H Gangadhara Bhat, chairman of the Marine Geology Department, Mangaluru University, says that, with the increase in concrete structures or built-up lands, the city is undergoing a phenomenon called ‘urban heat islands’.

“The temperature in the concrete areas of such ‘urban heat islands’ is 3 to 5 degrees Celsius higher than the surrounding areas. This is because concrete structures absorb heat during the day but are unable to shed it in the night. The heat stays on the surface, making such areas hotter to live in,” he explained.

Uncertain future

Dr H Gangadhara Bhat, chairman of the Marine Geology Department, Mangaluru University, said that Mangaluru receives over 4,000 mm of rainfall every year.

“Unplanned concreting of the land, however, prevents water from percolating into the soil and recharging the water table. Thus, reforms and policies need to be undertaken to allow use of pervious material that allows water to seep into the ground. The conservation of catchment areas can help in reducing the water crisis. Sustainable resources for construction that reduces the trapping of heat on the surface has to increase,” he stressed.

Sanchit Anchan says that there is a need to increase the green cover of the city and people need to be involved in protecting the wetlands and grasslands.