On design flood levels of the Danube river at Novi Sad

Abstract

Protection of the city of Novi Sad from floods relies mainly on levees along the banks of the Danube River. These levees were reconstructed after a great flood in 1965, when they were designed to protect the city from a 100-year flood level. This design flood level was the result of frequency analysis of annual maximum water stages for a 21-year long record (1947-1967). Such a choice of the observed record for frequency analysis resulted in levee heights that secured additional protection of Novi Sad from floods in last 40 years. Any other choice of record length and period would have resulted in lower design levels and poorer protection from floods. The paper discusses the effects of the choice of the subrecord on design flood level by investigating results of flood frequency analysis for different periods of observed water stages of the Danube at Novi Sad. The results show that the level of flood protection of the city of Novi Sad is now lower then designed 40 years ago.

Zaštita Novog Sada od velikih voda oslanja se najvećim delom na nasipe duž obala Dunava koji su rekonstruisani posle velike poplave iz 1965. godine, kada su dimenzionisani na 100-godišnju veliku vodu. Merodavni nivo vode za dimenzionisanje nasipa određen je tada na osnovu statističke analize niza od 21 maksimalnog godišnjeg vodostaja (1947-1967). Vreme je pokazalo da je taj niz dao merodavni vodostaj s kojim je Novi Sad imao dodatnu zaštitu od velikih voda tokom poslednjih 40 godina. Svaki drugačiji izbor niza za statističku analizu imao bi za rezultat niži merodavni vodostaj i niže kote nasipa. U radu se razmatra uticaj izbora niza maksimalnih godišnjih vodostaja na rezultate statističke analize i na vrednosti merodavnih vodostaja na Dunavu kod Novog Sada. Rezultati pokazuju da je stepen zaštite Novog Sada od plavljenja ispod projektovanog.