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REVIEW AND ANALYSES OF SOME MAXIMAL DISCHARGES IN EUROPE

This paper reviews the occurrence of extreme water runoff and its impact on flash-floods and regional floods. It focuses on the challenges of predicting extreme water discharge in small torrents and explores the correlation between water discharge and catchment area. Using statistical analysis, the study examines the relationship between catchment area, discharge, and specific discharge values. The findings highlight the importance of understanding the characteristics of small torrents and the need to mitigate the damage caused by extreme water discharges.

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REVIEW AND ANALYSES OF SOME MAXIMAL DISCHARGES IN EUROPE

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  1. BALWOIS 2006 Conference REVIEW AND ANALYSES OF SOME MAXIMAL DISCHARGES IN EUROPE Ivan Blinkov1, V.Al.Stanescu2 1Faculty of forestry – Skopje , Dept. of Land and Water E-mail: blinkov@ukim.edu.mk; 2National Institute of Meteorology and Hydrology - Romania

  2. Very often after intensive and long-lasting droughts there is occurrence of extreme water run-off which leads to flash-floods or regional floods. • Although modern technology have rapid development, it is not known yet how to predict the extreme water discharge appearance of the small torrents. With all modern technology and\new approache in spatial or urban planning we can only minimize the damages caused by flash-floods of bigger rivers. • There are a difference between small torents and rivers, the time base of the hydrogram is very small and the extreme discharges appear unexpectedly, they reach the pick very fast (quickly) and there is wave retardation for a very short time. Therefore forecast of the appearance and size of the maximal discharges is very hard to be realized.

  3. Objectives and Methods • Aim of this paper is to try to establish some correlation between water discharge and other factors. • The full data contains 657 values. Part of these data is officially published in IAHS publications, and part is from the personal data of one of the authors of this paper. In the database there are very small catchments (like the small torrents), but also there are big rivers like Dounau. • The basic data contain: name of the stream, profile, state, catchments area, registered or calculated discharge, date and note (comment). • First, according to the catchments area F (km2) and maximal discharge Qmax (m3/s) it is calculated the specific discharge value Qsp (m3/s.km2) too.

  4. Basic statistical parameters: number of information (N), average value (Xsr), maximal value (Xmax), minimal value (Xmin), standard deviation s), variety coefficient (Cv) and symmetry coefficient (Cs). • Analyzes of full series. • Analyzes of classified series by the catchement area): < 50 km2; 50.1<F<100 km2; 100.1<F<200 km2; 200.1<F<500 km2; 500.1<F<1000 km2; 1000.1<F<2000 km2; 2000.1<F<5000 km2; 5000.1<F<10000 km2; 10000.1<F<50000 km2 and catchments with area more than 50000.1 km2. • Analyzes of classified series by the specific discharge • Then it is calculated some ratio between the catchments area, discharge and specific discharge i.e.: Qmax = f (F) and Qsp = f (F).

  5. Basic parameters of the data series

  6. 10 highest discharges

  7. 10 highest specific discharges

  8. Ratio Qmax=f(F) Ratio Qsp=f(F)

  9. Analyzes of selected (classified) data Criterias for classification • Catchment area ( F < 100 km2) • Qsp > 10 m3/s.km2.

  10. Basic parameters of grouped data series

  11. Basic parameters of grouped seriesQsp > 10 m3/s.km2

  12. Qsp = f (F) Qmax= f (F) where Qsp > 10 m3/s.km2

  13. Conclusions

  14. Characteristic of small torrents are extreme values of the specific discharge (Qsp – m3/s.km2). It is obvious that these kind of specific discharges are happening in catchments areas under 236 km2 • Between large discharges value and catchments area there is proportional linear correlation (Y = 0.0803 x + 931.31). The determination coefficient is R2= 0.6422, which shows good correlation. • Between specific discharge and catchments area there is disproportional (Y = 27.485 x -0.5212) but strong correlation (R2=0.6613). • When data is grouped according to the catchments area, got functions are similar, but determination coefficients shows low correlation.

  15. Between extreme specific discharges (Qsp>10) and proper, appropriate catchments areas there is low negative correlation R2 = 0.2056, and Y = 21.083 x – 0.0982. • There is interesting correlation between water discharges and catchments area right in these cases when are got extreme specific discharges. The dependence is linear (Y = 13.401 x + 38.583). By the way it is got almost functional dependence. • Large water discharges are rare phenomena, but they have unbelievable (very bad, big) consequences on the whole environment.

  16. We are lucky that in Macedonia never had happened discharges with those kinds of dimensions like the big European rivers. But, that is possible with the small water discharges. It’s enough if we remember of Negotinska Reka case, also there are other registered cases, but with smaller dimensions: river Pena, Dzepchishki Poroj, Anska Reka and other smaller torrents.

  17. Blagodaram na vnimanieto Thank you for your attention

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