Figure 2 Urban area expansion of Chennai

disadvantages. The groundwater potential along the shore was significant, and because the majority of the population relied on groundwater, it was advantageous to the locals. The sandy nature of Chennai's coastline encourages precipitation to percolate into the earth, hence raising groundwater levels. Many developers were drawn by the potential groundwater, and much of the development in terms of building construction has occurred along the shore for up to 30 to 40 kilometres.

As a result of overdevelopment and overexploitation of groundwater, the situation quickly deteriorated.

The cause for natural rainfall percolation was quickly discovered to be interrupted by building development.Residential areas were constructed in low-lying locations where natural drainage systems gathered water. The builders who built these locations paved over the setback areas as well, preventing water from percolating into the soil or ground and reaching the groundwater table. Rainwater was instead diverted towards the streets, which were all similarly paved, resulting in waterlogging and flooding. Simultaneously, when groundwater is depleted at such a rapid rate, saltwater seawater is ready to take its place. The hazard was not anticipated by the creators.

Figure 2 Urban area expansion of Chennai.

Source: Vijayan, Prem (2017): Care Earth trust. A touch of green.

Rainfall is directly accountable for the flooding in the residential neighbourhood, according to reports. It should not be forgotten, however, that allowing and contributing to the filling of traditional water bodies has resulted in the disruption of rainwater's natural drainage system.

Rainwater that would formerly percolate to the groundwater or eventually run out to sea is now disrupted by building and urban interventions in the name of development, resulting in waterlogging and flooding. Using floods as an example, the map below (Figure 3) depicts the depletion of multiple water bodies to create space for building construction, which is a clear evidence of bad land use planning.

The city of Chennai (formerly known as Madras) began to overcrowd following World War II.The only places to stay were close-knit street-side row houses. Soon after, the housing demand shifted, with powerful individuals and the financially well-off looking for bungalows with gardens.

To meet this requirement, the city's urban planners looked to the massive lake body on the city's western outskirts. The Long Tank, which included the Mylapore Tank and the Nungambakkam Tank, covered an area of 18 square kilometres, as depicted in Figure 3. It was shortly emptied to make room for Thyagaraya Nagar, or T. Nagar, a housing and shopping district. The city's main lake was never considered for water supply by municipal planners or lawmakers.

T. Nagar was regarded as Madras' pinnacle achievement in urban design, despite the fact that the same region might have sheltered the city during floods or droughts. The choice had a major political impact, as seen by the fact that the roads, parks, and even the neighbourhood itself were named after members of the ruling political party (The History Of Providing Drinking Water To Chennai , n.d.).