Imapct of unplanned urban growth in eco-sensitive areas: A case of Doon valley

Abstract

Doon Valley was recognized as an Eco-sensitive Area (ESA) by the Ministry of Environment, Forests and Climate Change in 1989 after the ill-effects of limestone mining began to affect the ecologically rich region due to deforestation, choking of perennial streams, landslides, etc. This notification was an attempt to lay restrictions on certain activities like tourism, industries, mining, grazing and land-use planning in the region. However, in the year 2000, the state of Uttarakhand was formed and Dehradun was declared as its interim capital. Since then, the city, located within the valley, has undergone rapid urban growth, most of which has not been in a planned manner. This has resulted in the conversion of large patches of agricultural lands, open forests and river catchments to built-up, posing a threat to the sustenance of these resources in the ecologically sensitive region. This study attempts to analyze the environmental impacts of unplanned urban growth of Dehradun, particularly after its declaration as the interim state capital. For this, first, the pattern of urban growth was understood by studying the decadal changes in land use land cover between 1990 and 2019. It was found that most of the conversion to built-up has taken place in agricultural areas, followed by scrub lands and water bodies. Then, GIS-based eco-sensitivity analysis was carried out for the entire valley based on ecological factors such as slope, elevation, vegetation index, water index and land-use degree, using which the region was classified into four categories, that is, highly sensitive, moderately sensitive, less sensitive and non-sensitive areas. On the basis of these two analyses, sites were selected within Dehradun Urban Agglomeration to assess the impact of urban growth on river systems, agriculture and biodiversity. Firstly, impact on river systems, due to urban densification within Dehradun city, was studied. This involved detailed study of the catchment of Rispana river that flows through the city of Dehradun, highlighting the issue of the increasing number of slums along the river. The Soil Conservation Service – Curve Number (SCS-CN) method was used to assess the impact of increase in built-up on runoff that feeds the river’s flow. Secondly, the impact on agriculture was studied due to sprawling, dispersed development in rural areas. For this, Natthuwa wala village, which is now a Census Town, was surveyed, where large scale conversion of agricultural land to built-up has been taking place. Finally, impact on biodiversity, due to urban settlements getting closer to Protected Areas, was studied, wherein settlements in and around Lachhiwala wildlife corridor abutting Rajaji National Park were surveyed. These surveys were conducted in the selected sites, mostly in the form of in-depth, unstructured interviews of residents or natives. Government officials and experts were also contacted to gather relevant information regarding the impact of rampant urban growth of Dehradun in the last two decades. The information collected was further analyzed, based on which, site-specific and broad level recommendations and proposals were formulated. Overall, both qualitative as well as quantitative analysis techniques were used in the study. While quantitative analysis was based mostly on secondary data, primary surveys of the selected areas established the qualitative side of the research. Also, thematic maps were generated, wherever necessary, to strengthen the spatial aspect of the study.