Nehir Ağzı Sediment Birikiminin Taşkın Riskine Etkisi: Sakarya Nehri Örneği

Öz

Taşkın, dünya çapında can ve mal kaybına neden olan doğal bir afettir. Taşkınlar tahmin edilebilir ve zararları azaltılabilir. Çeşitli doğal ve insan kaynaklı faktörler taşkınlara neden olabilir. Sediment hareketi nadiren de olsa taşkınların nedenlerinden biri olarak sayılabilir. Sakarya Nehri yatağı ve nehir ağzı, sediment birikimi nedeniyle taşkınlar için riskli alanlardan biridir. Sakarya Nehri üzerindeki taş ocaklarının faaliyetleri nedeniyle nehrin taşıdığı sediment miktarı artmakta ve nehir yatağı morfolojisi zarar görmektedir. Nadiren de olsa sedimantasyon nedeniyle nehir ağzı tamamen kapanmakta, bu durum kıyı taşkınları ve deniz araçlarının alabora olması gibi can ve mal kaybına yol açan birçok felakete neden olmaktadır. Bu nedenle, Sakarya Nehri ağzında sediment birikimine bağlı taşkınların oluşumu araştırılmıştır. Sakarya Nehri'nin mansap kısmında ve Karasu ilçesinde 5, 10, 25, 50, 100 ve 500 yıllık dönüş periyodu akışları, nehir ağzının sediment birikimi sebebiyle yetersiz deşarj olması durumunda 2D taşkın modeli ile analiz edilmiştir. Bu dönüş periyotları için su derinliği, hız ve taşkın tehlike haritaları hazırlanmıştır. Taşkının Karasu ilçesi üzerindeki etkisi, etkilenen binalar ve etkilenen alan (ha) açısından analiz edilmiştir. Böylece memba bölgesinde nehir yatağına yapılan müdahaleler sonucunda mansap bölgesinde meydana gelen taşkınların etkileri analiz edilmiştir.

Anahtar Kelimeler

• Sakarya Nehri
• Sediment
• Taşkın
• Derinlik
• Tehlike

The Impact of River Mouth Sediment Deposition on Flood Risk: The Case Study of The Sakarya River

Öz

Flooding is a natural disaster that causes loss of life and property worldwide. Floods can be predicted and their damages can be reduced. Various natural and man-made factors can cause floods. Sediment movement can be counted as one of the causes of floods, albeit rarely. The Sakarya River bed and river mouth is one of the risky areas for flooding due to sediment deposition. Due to the activities of quarries on the Sakarya River, the amount of sediment carried by the river increases, and the damage to the river bed morphology. In rare cases, the mouth of the river is completely closed due to sedimentation, which has caused many disasters such as coastal flooding and capsizing of marine vessels, leading to loss of life and property. Therefore, the occurrence of floods due to sediment deposition at the mouth of Sakarya River was investigated. The 5, 10, 25, 50, 100, and 500-year return period flows in the downstream part of the Sakarya River and Karasu district were analyzed with the 2D flood model in case of insufficient discharge from the river mouth. Water depth, velocity, and flood hazard maps for these return periods were prepared. The impact of flooding on Karasu district was analyzed in terms of affected buildings and affected area (ha). Thus, the effects of the floods occurring in the downstream region as a result of the interventions to the river bed in the upstream region were analyzed.

Anahtar Kelimeler

• Sakarya River
• Sediment
• Flood
• Depth
• Hazard

Kaynakça

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