Impact of Maintenance Methods of an Overgrown Lowland River on its Hydraulic Conditions

Abstract The paper presents the results of numerical analyses carried out in the IRIC environment on the Nays2DH hydrodynamic model regarding the impact of plants in the riverbed and watercourse maintenance on hydraulic conditions. The research material was collected for the actual input variant in October 2018 on the Ślęza River in Wrocław. The constructed and calibrated model was reconfigured on basis of the existing vegetation in three possible variants related to river maintenance: W0 variant - leaving the vegetation in the riverbed, W1 variant - removing all vegetation in the riverbed, variant W2 - removing vegetation in the 2.0 m strip from the right bank, W3 - removing of vegetation in a strip of 2.0 m from the bank, alternately on the right and left bank. Hydrological boundary conditions were flows from 0,32 to 5 [m3/s]. For four variants, the dependence of flows on the water table location, maximum and average velocities in the channel, and maximum and average shear stresses in the channel were analysed.