Conclusion and discussion

Poor environment, infrastructure and living conditions due to unplanned urbanization has been a major concern in metropolitan cities of India. Understanding spatio-temporal patterns of urban growth and its impacts on environment is possible with the availability of remote sensing data acquired through space borne sensors. In the current study, land cover dynamics during 1991-2013 and 1989-2014 were assessed through vegetation index. Chennai which had a lush green cover of around 70.47% in 1991 consistently declined accounting to about 50% in 2013. Land use dynamics analyses during four decades show a drastic increase of urban area by more than 20 times with the conversion of grazing, agricultural and open areas. Urban area was found to be spread over 77104 ha (2013) in Chennai region and 75768 ha (2014) in Hyderabad region. This tremendous growth may be clearly visualized in industry oriented land fragments like Ponneri, Avadi, Sriperumbudur in Chennai region and Malakpet, Madapur, Bollaram, Kukkatpally etc. in Hyderabad region. Higher overall accuracy values ranging from 86% - 97% (Chennai) and 87% - 94% (Hyderabad) proves the consistency of land use classifications. Shannon’s entropy values indicate of sprawl or dispersed growth in recent years. Spatial metrics were used considering the area, shape and contagion obtained through the moving window method to quantify the urban built up land density. The analysis also revealed that the process of densification at the city center (CBD: Central business district) with the initiation of the process of aggregations during 2010’s. Predication of urban growth in 2025 of complex urban landscape systems was done with integrated fuzzyAHP, cellular automation and Markov chain techniques. The predicted spatial patterns of 2013 (Chennai) and 2014 (Hyderabad) were validated by comparing with the actual land use show conformit with higher accuracies and kappa statistics. The spatial analyses helped in visualizing and identification of urban growth regions and assessment of impacts on natural resources and agrarian lands. There has been a spurt in population and increased population density in the urban core; this would put lot of pressure on improving the accessibility of basic amenities to citizens both in Chennai and in Hyderabad. Social factor (S) and economy are two major factors that play a vital role in managing urban strata in a city and urban space. Social amenities as considered in the study in modelling the land use change are more concentrated in the city in Hyderabad, pushing growth around the region. Whereas in Chennai social amenities are present in both core city and outskirts in large number have fueled the growth and would be main factors that would allow growth in coming years. Chennai being a hub of industry and Hyderabad being a hub of information sector units would provide a huge push of economic growth near outskirts of the city and in the buffer zones thus all these factors showed a great influence in rampant urban sprawl and urbanization in both study regions.
The simulation and prediction of land uses with violations of CDP show of intensified urban growth within CMDA and HMDA boundary limits. Compared to this, with constraints of CDP implementation, indicate of fairly distributed built-up along highways such as Avadi, Triuchinapalli, Ponneri (NH- 4, 45 and 716 roads) in Chennai region and Kushaiguda, Safilguda, Uppal, Ghatkesar, Katedan, Serilingampally, Patancheru (NH – 5,7,9 and 202 roads) in Hyderabad region on the peripheries of metropolitan boundary zones. Urban areas are observed to be increased from 77104 ha (2013) to 151428 ha (2025) in Chennai and 75768 ha (2014) to 175009 ha (2025) in Hyderabad. These findings aid policy makers in provisioning basic amenities and adequate infrastructure in rapidly urbanizing landscapes. Decline of vegetation and wetlands in the landscape will lead to instance of frequent flooding, traffic congestions, higher level of pollutants, water scarcity, etc. which necessitates sustainable management of natural resources.