TYPICAL FLOOD PATTERNS ON THE FEKETE KÖRÖS AND FEHÉR KÖRÖS RIVERS AND THE POTENTIAL FLOOD CONTROL DEVELOPMENTS

Owing to the physico-geographical situation of the country, important and steadily growing public interests have been attached to flood and inundation control for centuries in Hungary. The vast lowlands of the Hungarian Plains form the deepest part of the Carpathian Basin. The flood waves emerging from their steep mountain catchments in the Carpathians and the Alps tend to overtake each other causing often emergency situations. The flood embankments– main line levees – along the rivers form the backbone of the flood control schemedeveloped in Hungary from the middle of the past century to these days. At the same time, the flood control experiences gained over the recent 30 years have demonstrated that along with the development, strengthening to the prescribed dimensions of the embankments along the river, new engineering solutions and methods must also be applied. These include – among others – local flood control schemes . The method of emergency flood storage has been introduced as part of the latter on some rivers, involving the establishment of lowland emergency flood reservoirs . The aim of emergency storage is to detain temporarily part of the flood volume and to lower thereby the peak level of the flood wave. The method of emergency storage has been applied repeatedly on the Koros rivers during the past decades. The flood levels on the Koros rivers have been observed to rise steeply over the recent decades. The analyses and assessments of the Koros floods of the past decades have contributed a wealth of data and information for development planning. The flood travel pattern on the Fekete Koros and Feher Koros rivers have changed significantly. The peak flood levels and the peak flood discharges and water volumes have risen; the flood surface profiles have changed. Flood control in the Koros Valley has commanded and will continue to command also in the future special attention. On the Koros rivers – yet also on some other Hungarian streams – the ’conventional’ constructional methods of providing a higher level of flood safety, by raising the crest and increasing the cross sectional dimensions of the embankments are alone inadequate and that resort must be made to active flood control solutions, i.e., emergency flood storage.