Assessment of the flood risk reduction alternatives in municipalities of the upper Myjava and Teplica rivers, Slovakia

Abstract

Flood risk management often uses multi-criteria analyses, which allow the most suitable alternatives for flood risk reduction to be chosen. We used the SAW (Simple additive weighting), AHP (Analytical hierarchy process) and TOPSIS (Technique for the order of preference by similarity to the ideal solution) methods to evaluate the alternatives in seven cadastral areas of the Upper Myjava and Teplica river basins. Economic, social, environmental, and technical criteria were chosen based on literature research. We compared the current situation (A0), alternatives proposed by watercourse administrators (A1), endangered inhabitants (A2), alternatives based on previous flood risk research (A3) and a combination of the previous (A5-A7). Most expensive alternatives include building new water structures, alternatives with lectures had the highest social impact and none of the alternatives had a significant effect on the environment. With three different sets of weights, we obtained 9 sets of results. In most cases, A3 was in the first place as the best alternative for flood risk reduction. With the TOPSIS method, the results were different. In cadastral areas where seven alternatives were compared, the A5 or A7 get first place. At the same time, we analysed the methods of selecting the most suitable alternative by watercourse managers, which showed a few shortcomings.