Türkiye’de Taşkınların FlooDOT Tabanlı İncelenmesi ve Farklı Veri Kaynaklarının Mekânsal Karşılaştırılması

Öz

Taşkınlar, akarsuların yataklarını terk ederek çevresine yayılması ve nispeten çukur alanları doldurmasıyla birlikte hem ölümcül hem maddi sonuçlara yol açmaktadır. Bu açıdan gerek taşkınların oluşum mekanizmalarının gerekse neden olduğu sonuçların anlaşılması için taşkınlara ait çeşitli özelliklerin yer aldığı envanterlerin varlığı oldukça önem taşımaktadır. Küresel envanterlerin Türkiye gibi ülkelerin bölgesel ve ulusal ölçekteki süreçlerin anlaşılmasında gerekli olan veri tabanlarını sağlamadığı, sadece gazete arşivlerine veya resmi kaynaklara dayalı verilerin ise süreçleri açıklamada yetersiz kaldığı görülür. Bu eksikliği gidermek amacıyla Türkiye Taşkın Envanteri (FlooDOT) oluşturulmuştur. Bu çalışmanın amacı, Türkiye'de 1928-2022 yılları arasında farklı veri kaynakları kullanılarak oluşturulan taşkın envanterini tanıtmak, bu envantere dayanarak taşkınların zamansal ve alansal değişimlerini ortaya koymak ve kullanılan veri kaynaklarının mekânsal farklılıklarını karşılaştırmaktır. Bu amaç doğrultusunda Getis-Ord Gi* istatistik kullanarak farklı kaynaklardan elde edilmiş taşkın envanterlerinin mekânsal değişimleri ve oluşturdukları sıcak-soğuk bölgeler incelenmiştir. Sonuçlara göre, toplamda 3300 ölümcül taşkın tespit edilmiş ve 6799 taşkın olayı sonucunda envantere 9181 taşkın noktası eklenmiştir. Taşkınların zamansal dağılışı, Türkiye’de çeyrek yüzyıllık bir döngüye ve bimodal bir karaktere sahip olduğunu açıkça ortaya koymaktadır. Ayrıca, 1972 ve 2001 yılları taşkınların zamansal dağılışında ayrık yıllar olarak tespit edilmiştir. Diğer yandan Türkiye’nin her yerinde taşkın olayı görülmekle birlikte, Doğu Karadeniz’in hem taşkın sayısı hem de ölümcül taşkınlar açısından bir sıcak bölge olduğu belirlenmiştir. Doğu Karadeniz havzasından sonra Sakarya ve Fırat-Dicle hem ölümcül taşkın hem de taşkın sayısı bakımından öne çıkmaktadır. Ayrıca, Getis-Ord Gi* istatistiği kullanarak yapılan analiz sonucunda kurumsal olarak elde edilen Devlet Su İşleri taşkın envanteri verisiyle ve çeşitli kaynaklardan elde edilen verilerin mekânsal farklılıklarının karşılaştırılmasından elde edilen sonuçlar Türkiye’de soğuk bölgeye rastlanmadığını ve elde edilen sıcak bölgelerin ise farklı envanter kaynaklarının Türkiye’de taşkınların görüldüğü bölgeler açısından farklı sonuçlar ürettiğini ortaya koyduğu anlaşılmaktadır. Bu durum FlooDOT envanterinin Türkiye’deki taşkın süreçlerini mekânsal olarak iyi yansıttığı ve envanterin bu açıdan küresel envanterlerin yarattığı veri boşluğunu kapattığı görülmektedir. Bu nedenle envanter oluşturma süreçlerinde mevcut olan tüm kaynaklardan toplanan kayıtların kullanılması taşkın tehlike ve duyarlılık analizleri için büyük bir avantaj sağlamaktadır.

Anahtar Kelimeler

• Taşkınlar
• taşkın envanteri
• FlooDOT
• Getis-Ord Gi*
• Türkiye

FlooDOT-based Analysis of Floods in Turkey and Spatial Comparison of Various Data Sources

Öz

Floods occur when rivers overflow their banks and rapidly spread into surrounding areas, filling nearby depressions and causing both fatalities and economic losses. In this context, the existence of inventories that include various characteristics of floods is of great importance for understanding both the flood generating mechanisms and the consequences they produce. Global inventories have been found insufficient in providing the necessary databases to understand regional and national-scale flood processes in countries like Türkiye, while data based solely on newspaper archives or official sources have proven inadequate for explaining such processes. To address this gap, the FlooD Inventory Of Türkiye (FlooDOT) was developed. The aim of this study is to introduce the flood inventory created using various data sources for the period between 1928 and 2022 in Türkiye, to reveal the temporal and spatial variations of floods based on this inventory, and to compare the spatial differences among the data sources used. In line with this aim, spatial variations of flood inventories obtained from different sources and the hot and cold spots they form were analysed using the Getis-Ord Gi* statistic. According to the results, a total of 3300 fatal floods were identified, and 9181 flood locations were recorded in the inventory based on 6799 flood events. The temporal distribution of floods in Turkey clearly reveals a quarter-century cycle and a bimodal pattern. Furthermore, the years 1972 and 2001 were identified as outlier years in the temporal distribution of floods. While flood events have been observed across the entire country, the Eastern Black Sea region has been identified as a hot spot in terms of both the number of floods and the frequency of fatal floods. Following the Eastern Black Sea basin, the Sakarya and Euphrates-Tigris basins stand out in terms of both fatal floods and total flood occurrences. Moreover, the comparison of spatial differences between the institutional data from the State Hydraulic Works (DSİ) and other sources, based on analyses using the Getis-Ord Gi** statistic, showed that no cold spots were found in Turkey, and that hot spots varied depending on the data source used. This finding indicates that the FlooDOT inventory provides a reliable spatial representation of flood processes in Türkiye and helps to fill the data gap created by global inventories. Therefore, utilizing records gathered from all available sources during inventory creation processes offers a significant advantage for flood hazard and vulnerability analyses.

Anahtar Kelimeler

• Floods
• flood inventory
• FlooDOT
• Getis-Ord Gi*
• Türkiye

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