Evaluation of Empirical Modelling Techniques for the Estimation of Sediment Amount in Rivers

Öz

The sediment transport processes of streams have been the subject of research for many years. Sediment amount carried by a river is strongly correlated with the river’s flow rate and sediment concentration. This study aims to represent this correlation and to estimate the sediment amount using four different modelling techniques: MLR, PLS, SVM, and ANN. Records of river flow, sediment concentration and sediment amount obtained from the Göksu River, located in the Eastern Mediterranean region of Turkey, are used as input data in the models. The aim of is this study is to evaluate the effectiveness of ANN modelling in the estimation of sediment amount carried by river flow. Fifty percent of the data are used as training set to develop the models. The other half of the data is used for verification set. The performance of the four models is evaluated by determination coefficient of prediction set (r²_pred). The results indicate that ANN is the most effective method (r²_pred = 0.94), followed by SVM (r²_pred = 0.72). MLR and PLS methods are the least effective techniques (r²_pred = 0.67) for estimating sediment amount in the Göksu River. Therefore, ANN approach is further studied to propose the best configuration for the prediction of river sediment amount.

Anahtar Kelimeler

• Sediment amount,River,Modelling,ANN

NEHİRLERDE SEDİMENT MİKTARININ BELİRLENMESİNDE AMPİRİK MODELLEME TEKNİKLERİNİN DEĞERLENDİRİLMESİ

Öz

Nehirlerdeki sediment taşınım süreçleri uzun yıllardır önemli bir araştırma konusu olmuştur. Nehirlerde taşınan sediment miktarı, nehrin akımı ve sediment konsantrasyonu ile güçlü bir ilişki içerisindedir. Bu çalışma, bu ilişkiyi göstermeyi ve dört farklı modelleme tekniği olan MLR, PLS, SVM ve ANN metotlarını kullanarak sediment miktarını hesaplamayı amaçlamaktadır. Türkiye’nin Doğu Akdeniz bölgesinde yer alan Göksu Nehri’ne ait akım, sediment konsantrasyonu ve sediment miktarı modellerde girdi verisi olarak kullanılmıştır. Bu çalışmanın amacı, nehir akımıyla taşınan sediment miktarının tahmin edilmesinde ANN modelleme tekniğinin etkisini değerlendirmektir. Verilerin yüzde ellisi modelin geliştirilmesi için öğrenme seti olarak, kalan veriler ise modelin validasyonu  için test seti olarak kullanılmıştır. Test setinin belirleme katsayısı (r²_pred) dikkate alınarak dört modelin performansı değerlendirilmiştir. Sonuçlar ANN’nin en etkili yöntem olduğunu (r²_pred = 0.94) ve onu SVM’nin takip ettiğini (r²_pred=0.72) göstermektedir. MLR ve PLS ise Göksu Nehri’ndeki sediment miktarının belirlenmesinde en az etkili yöntemlerdir  (r²_pred = 0.67). Bu nedenle, nehirdeki sediment miktarını tahmin etmek için en etkili yöntem, ANN’nin farklı konfigürasyonları çalışılarak araştırılmıştır.

Anahtar Kelimeler

• Sediment miktarı,Nehir,Modelleme,ANN

Kaynakça

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