Changes in Geographical Features

India’s exposure to floods encompasses over 40 million hectares of its 329 million-hectare landscape, marked by heightened vulnerability (NDMA). This susceptibility is notably accentuated in hilly regions, where flash floods—sudden and intense deluges as seen recently in Himachal Pradesh—intensify due to various catalysts. Prominent factors include altered river courses, increased urbanization, and climate change impacts. However, out of these, deforestation looms large as a pivotal contributor, amplifying the risk substantially as explained below:

Deforestation and Increased Vulnerability to Flash Floods in Hilly Regions of India:

• Reduced Vegetation Cover: Eliminating trees and plants reduces natural cover that absorbs and slows rainwater, as evident in the Western Ghats. This impact was stark during the 2018 Kerala floods, where deforested areas experienced exacerbated flooding due to diminished vegetation.
• Surface Runoff: Without trees and plants to intercept rainwater, there’s increased surface runoff, causing water to flow rapidly downhill, leading to higher flash flood potential, as vividly seen in the 2010 Leh flash floods in Ladakh.
• Loss of Root Systems: Tree roots, pivotal in soil cohesion, lose their presence through deforestation, thus compromising soil structure and rendering it prone to erosion, as highlighted by the 2009 Nilgiris flash floods.
• Landslides: Deforested slopes are more prone to landslides during heavy rainfall, especially in hilly regions. For instance, in the 2013 Uttarakhand floods, deforestation played a role in triggering landslides that worsened the disaster.
• Reduced Water Infiltration: Trees enhance water infiltration into the soil. Deforestation decreases this capacity, leading to less water being stored underground and more water running off quickly. The 2000 flash flood along the Sunkoshi River in Darjeeling, West Bengal, serves as an example.
• Flash Flood Peak Intensity: Deforested areas experience higher peak intensities during flash floods as water rushes downhill more swiftly. For instance, the flash floods in Shimla in 2015 were characterized by high peak intensity due to deforestation in surrounding areas.
• Riverbank Erosion: The absence of vegetation along riverbanks caused by deforestation contributes to bank erosion and alters river courses, increasing flood vulnerability, as exemplified by the 2017 floods in the Teesta River of Sikkim.
• Soil Erosion: The stabilizing influence of trees and plants on soil is disrupted by deforestation, leading to escalated soil erosion that results in sediment accumulation in rivers and streams, intensifying flood hazards. This phenomenon was evident during the 2004 floods in Darjeeling, West Bengal.
• Increased Sedimentation: Deforestation results in increased sediment flow into rivers. Sedimentation can clog waterways, potentially causing floods. For instance, the 2013 floods in the Ganges-Brahmaputra-Meghna basin were worsened by sedimentation caused by deforestation.
• Altered Microclimates: Deforestation disrupts rainfall patterns, sometimes leading to intense, sudden downpours that trigger flash floods, exemplified by the 2014 and 2021 flash floods in Kashmir and the Garhwal region, respectively.
• Loss of Buffer Zones: Forests, acting as natural buffers by impeding and absorbing surplus rainfall, serve as protective areas. Their removal, as seen in the 2005 Agumbe, Karnataka flash floods, exacerbates the intensity of such disasters.
• Disrupted Hydrological Cycle: Deforestation disrupts the natural water cycle, affecting water storage, evaporation, and precipitation patterns, which can lead to unpredictable flash floods. The Malabar Hill flash flood in Mumbai during 2005 provides an instance of how deforestation disrupts the hydrological cycle.

Amidst the complicated tapestry of nature, deforestation significantly amplifies the susceptibility of flash floods in Indian hill regions. The journey ahead calls for collective action, policy reinforcement, and a harmonious coexistence with the environment. This restorative symphony envisions a future where deforestation yields to sustainable coexistence, diminishing flash flood vulnerability.