MODELING OF FLOW DURATION CURVES USING MATHEMATICAL METHODS IN THE EASTERN BLACK SEA BASIN

Öz

In hydrological studies related to water engineering, flow estimation plays a critical role, with flow duration curves (FDC) widely used as a key analytical tool. However, FDC can only be directly constructed at streamflow gauging stations with sufficient data; in regions with limited or no measurements, they must be estimated. This study estimates FDC through regionalization using mathematical methods in the Eastern Black Sea Basin. Streamflow data from 39 gauging stations, along with temperature and precipitation data from meteorological stations within the basin, were utilized. To capture the general shape of the FDC, logarithmic and exponential equations were applied to flow values corresponding to exceedance probabilities ranging from %0-100. Regression coefficients were calculated for each station. The exponential model yielded superior results, with a lower standard error of estimation (0,312) and a higher coefficient of determination (0,869) compared to the logarithmic model. Based on its better conformity to the overall FDC shape, the exponential model was selected. Its coefficients were then related to the topographic and climatic characteristics of stations. Two equations were developed to estimate the coefficient ae using drainage area and mean annual precipitation, while five equations were derived to estimate the coefficient be based on drainage area, drainage density, average stream slope, and mean annual total precipitation. The results demonstrate that the general shape of FDC at any location within the Eastern Black Sea Basin can be predicted using basin characteristics and the estimated ae and be coefficients.

Anahtar Kelimeler

• Flow Duration Curve
• Regression Analysis
• Eastern Black Sea Basin.

DOĞU KARADENİZ HAVZASINDA MATEMATİKSEL YÖNTEMLERLE DEBİ SÜREKLİLİK EĞRİLERİNİN MODELLENMESİ

Öz

Su mühendisliği çalışmalarında debi tahmini kritik olup, Debi süreklilik eğrileri (DSE) hidrolojide önemli bir araç olarak kullanılmaktadır. Ancak, sadece akım gözlem istasyonlarında doğrudan oluşturulabiliyorken, ölçüm eksikliği olan veya ölçümü bulunmayan bölgelerde DSE tahminle oluşturulmaktadır. Bu çalışmada, DSE’nin Doğu Karadeniz Havza’sında matematiksel yöntemlerle bölgeselleştirme ile tahmini yapılmıştır. Havzadaki 39 adet akım gözlem istasyonu debi verileri ile meteoroloji istasyonlarının sıcaklık ve yağış verileri kullanılmıştır. DSE’nin genel şekline uyumu açısından logaritmik ve eksponansiyel denklemler kullanılarak her istasyonun %0-100 aşılma olasılıklarına karşılık gelen debi verileri analiz edilmiş ve regresyon katsayıları hesaplanmıştır. Eksponansiyel denklemde tahminin standart hata değerinin 0,312 ile logaritmik olandan daha iyi sonuç verdiği, her bir istasyon için bulunan denklemlerde belirleme katsayısının 0,869 ile logaritmik denklemlerden daha iyi olduğu gözlenmiştir. Ayrıca DSE’nin şekline uygunluğu da göz önüne alınarak eksponansiyel seçilmiş ve denklem katsayıları istasyonların topoğrafik ve iklimsel özellikleriyle ilişkilendirilmiştir ae katsayısının drenaj alanı ve ortalama yıllık toplam yağış değerleriyle tahmin edilebildiği iki farklı denklem, be katsayısının drenaj alanı, drenaj yoğunluğu, akarsu drenaj ağının ortalama eğimi ve ortalama yıllık toplam yağış değerleriyle tahmin edilebildiği beş farklı denklem bulunmuştur. Çalışma sonucunda, havza özellikleri ile elde edilecek ae ve be katsayıları yardımıyla, Doğu Karadeniz Havza’sındaki herhangi bir noktada, DSE’nin genel şeklini tahmin edebilmemize imkân sağlanmıştır.

Anahtar Kelimeler

• Debi Süreklilik Eğrisi
• Regresyon analizi
• Doğu Karadeniz Havzası.

Destekleyen Kurum

Karadeniz Teknik Üniversitesi-BAP

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