Regional flood frequency analysis for<scp>Ç</scp>oruh<scp>B</scp>asin of<scp>T</scp>urkey with<scp>L</scp>‐moments approach: Fid-Bau Portal

Regional flood frequency analysis forÇoruhBasin ofTurkey withL‐moments approach

Aydoğan, D. / Kankal, M. / Önsoy, H.

AbstractIn this paper, a regional flood frequency analysis ofÇoruh Basin was performed with theL‐moments method. Because the area ofÇoruh Basin is large (21 100 km2), and the climatic, hydrologic, and topographic characteristics vary throughout the basin, it was divided into four sub‐regions for examination. Discordancy measure tests were performed for the sites located in each sub‐region. TheHheterogeneity test was carried out by performing 500 simulations with theKappa probability distribution for the homogeneity of the region. With the help of a diagram of theL‐moment ratios and by administering theZgoodness‐of‐fit measure test, the appropriate distribution was determined for each sub‐region. The distributions were used to identify the quintiles according to various probabilities of non‐exceedance. The accuracies of the estimated measured for the regional growth curves and quantiles were calculated usingMonteCarlo simulation. Finally, the flow values determined from the quantiles estimated with theL‐moments method were compared with those estimated previously with an at‐site frequency analysis (Gumbel distribution) on the basin master plan for four large dams in theÇoruhBasin.