Low-density debris flows and floods modeling in the Susuya river basin

Abstract

Significant area of Yuzhno-Sakhalinsk city within the river Susuya flood plain, a terrace above it and its tributaries are located in flood prone zone. The aim of this research was to estimate maximum characteristics of flash floods and low-density debris flows for the Susuya river and its tributaries, the Rogatka and Vladimirovka rivers. A one-dimensional model of unsteady water movement based on Saint-Venan equations was used. The modeling of river maximum characteristics include following tasks: 1) collect and analyze the data of past dangerous events, 2) process the initial information for the model, 3) simulate discharges of 0.1-10% exceeding probabilities with a change in the hydraulic-morphometric characteristics of the objects. The model does not take into account flow density, therefore numerical experiments were conducted with the increasing coefficient of roughness to identify optimal values of the parameter. The results can be further used in the construction design of residential buildings and infrastructure in Yuzhno-Sakhalinsk.