Mapping impervious surface area increase and urban pluvial flooding using Sentinel Application Platform (SNAP) and...

Area of Science:

• Environmental Science
• Urban Planning
• Remote Sensing

Background:

• Urban impervious surfaces (UIS) and urban pluvial flooding (UPF) significantly impact urban dynamics and environments.
• Monitoring UIS expansion and its link to UPF is crucial for sustainable urban development.

Purpose of the Study:

• To map the increase in impervious surface area (ISA) in three major Pakistani cities from 1992 to 2022.
• To map pluvial flood extent in selected urban areas using Sentinel-1 data.

Main Methods:

• Utilized the Global Impervious Surface Area Index (GISAI) on Google Earth Engine with Landsat time-series data to map UIS.
• Employed Sentinel-1 Ground Range Detected (GRD) data and the SNAP tool to map pluvial flood extents.

Main Results:

• UIS increased by 16.8% in Islamabad, 23.5% in Lahore, and 16.4% in Karachi.
• Lahore achieved the highest GISAI accuracy (93%), followed by Karachi (86%) and Islamabad (85%).
• Flooding predominantly occurred in areas with significant ISA growth over the past three decades.

Conclusions:

• Increased ISA directly correlates with enhanced UPF in major Pakistani cities.
• Sentinel-1 data effectively mapped flood-prone zones, aiding rapid detection.
• A modeling-based approach is recommended for identifying high-risk UPF locations for better urban management.