Temporal land use change and its effects on climate in Elmalı basin using GIS and remote sensing

Abstract Land use is vital in sustaining human activities, particularly in rapidly urbanizing regions like the Istanbul Metropolitan Area, where large-scale projects such as the Canal Istanbul, Third Airport, and Yavuz Sultan Selim Bridge have significantly impacted land use. These developments have driven population growth, leading to unplanned urbanization and environmental degradation, particularly in watersheds. In this study, the Elmalı Basin, a critical water source on the Anatolian side of Istanbul, was analyzed using Landsat-8 satellite imagery with a spatial resolution of 30 m for multispectral bands, covering the years 2013, 2015, 2018, and 2020. The results reveal a 36% increase in settlement areas, a decline in forest cover, and an increase in surface runoff from 78.76% in 2013 to 80.56% in 2020, mainly due to unplanned construction and climate changes. Temperature trends from 1979 to 2023 show an increase from 14.7 °C to 16.1 °C, while monthly precipitation anomalies highlight increasing variability in rainfall patterns. Moreover, the frequency distributions of monthly precipitation at the Florya and Göztepe stations show that low-intensity precipitation events are expected. In contrast, high-intensity events are rare, signaling drought and flood risks, which underscore the need for effective water management strategies. This study, which investigates the temporal changes in land use and their effects on climate, is crucial for providing preliminary insights that can inform future planning efforts.