Risk Assessment of Extreme Events along a River Flow

The present work considers the Struma River water flow on Bulgarian territory as a starting point for evaluation of maximum and minimum water flow using an original integral method. The risk assessment is determined by specific indices like the index Mmax,i for the deviation of the maximum water flow from the calculated norm of the maximum flow Qmax,0 and the index Mmin,i for the deviation of the minimum water flow from calculated norm of the minimum flow Qmin,0. The new integral approach introducing specific indicators for risk assessment like the indices Mmin,i and Mmax,i has been checked at three sampling locations of the National monitoring net along the Struma River: Pernik (in the beginning), Krupnik (in the middle) and Marino pole (at the border in Greece) for the period 1948-2006. A significant trend towards decreasing of Mmax,i index is outlined for the three points. On contrary, a significant trend towards increasing of Mmin,i index is found at Krupnik and Marno pole sampling points.