Author(s): Fainaz Inamdeen; Magnus Larson
Linked Author(s):
Keywords: Compound effects; Sea level; River flow; Numerical simulations
Abstract: Sea level (SL) and river flow (Q) are the primary factors that influence the water surface elevation (WSE) along a river in coastal areas. However, quantifying the combined effects of SL and Q on WSE is not straightforward due to the different behavior of these factors and their complex inter-relationship. Although the joint probability of the simultaneous occurrence on SL and Q can be quantified, there is no guarantee that the resulting WSE has the same probability as the combination. In this study, an alternative methodology was developed to quantify the compound effects of SL and Q on WSE along a river using the output from numerical simulations using long-term input series for SL and Q. Based on such simulations, empirical relationships were developed to directly determine WSE from SL and Q based on statistical analysis. The study was conducted over an 11-km stretch of the Rönner River in southern Sweden. The HEC RAS 1D hydraulic model was used for the numerical simulations. The results showed how the influence of SL decreases upstream, as well as increasing influence of Q. Around 5 km from the coast, SL and Q have nearly equal influence on WSE.
Year: 2026