GIS-BASED ANALYSIS OF TEMPORAL CHANGES IN THE SARIMEHMET DAM RESERVOIR (VAN-ÖZALP) USING LANDSAT SATELLITE DATA (1989- 2026)

Matpay B.

5 INTERNATIONAL LA K E VAN SOCIAL SCIENCES CONGRESS, Van, Türkiye, 12 - 14 Haziran 2026, ss.112-113, (Özet Bildiri)

  • Yayın Türü: Bildiri / Özet Bildiri
  • Basıldığı Şehir: Van
  • Basıldığı Ülke: Türkiye
  • Sayfa Sayıları: ss.112-113
  • Van Yüzüncü Yıl Üniversitesi Adresli: Evet

Özet

Global climate change and basin-based hydrological interventions are the primary factors threatening the sustainability of water reserves in ecosystems. This study aims to investigate the surface water changes in the Sarımehmet Dam, located in the Özalp district of Van province, which is of vital importance for agricultural irrigation and ecological balance, over a 37-year period (1989-2026). Multi-temporal images from the Landsat (4-5 TM, 7 ETM+, 8 OLI, and 9 OLI-2) satellite series were utilized in the research. To accurately differentiate between water and land on the reservoir surface, spectral band data were analyzed using the Normalized Difference Water Index (NDWI) and modified water indices. The acquired data were converted into spatial statistics within a GIS (Geographic Information Systems) environment, and change graphs of the dam's occupancy rates were generated. Analysis results reveal that while Sarımehmet Dam followed a fluctuating course due to climatic periods from 1989 to the mid-2015s, it entered an unprecedented, sudden, and rapid decline in water levels during the last decade (2016-2026). In particular, post-2020 data indicate that the reservoir area has dropped below critical thresholds, approaching an irreversible point of desiccation risk. This rapid decrease is associated with increasing evaporation rates in the region, decreasing snowfall, and uncontrolled agricultural irrigation pressure. The study emphasizes the urgent need for a revision of water management strategies in border regions and highlights the significance of remote sensing technologies in this process.