Problems, methods and technologies of combined 3D model construction for underwater and above-water relief

Andrey Gachenko,Alexei Hmelnov

doi:10.1051/e3sconf/202014902002

Abstract

In the article we describe the methods for construction of underwater 3D relief (bathymetry) and combining it with the corresponding ground relief (terrain) when the bathymetry information is of much lower quality than that of terrain. We have developed an algorithm for combining the low quality underwater relief with the higher quality ground relief using Delaunay triangulations. The resulting combined 3D model of relief has no noticeable artifacts and can be used to solve various hydrological tasks, such as computation of the HPP reservoir water level in dependence to the water discharges of the hydroelectric power plant. We have tested the technology for building combined relief 3D model in several scientific projects intended to estimate the changes in the coastline under various water flow scenarios in the basins of Angara River and Lake Baikal.

Highlights

The river bed of the Angara River on its more than 100 km stretch from the dam of the Irkutsk Hydroelectric Power Station (IHPS) to the start of the Bratsk Reservoir has rather complex structure with many islands, backwaters, channels and inflow junctions
To consider the risks of flooding of urban areas caused by increased water discharges through the dam of IHPS and the other river Angara inflows due to extreme weather conditions it is necessary to build the relief models to determine potential zones of flooding
By using sufficiently accurate relief model it will be possible to estimate the dependence of potential flooding boundaries on the water discharges

Summary

Introduction

The river bed of the Angara River on its more than 100 km stretch from the dam of the Irkutsk Hydroelectric Power Station (IHPS) to the start of the Bratsk Reservoir has rather complex structure with many islands, backwaters, channels and inflow junctions. To consider the risks of flooding of urban areas caused by increased water discharges through the dam of IHPS and the other river Angara inflows due to extreme weather conditions it is necessary to build the relief models to determine potential zones of flooding. By using sufficiently accurate relief model it will be possible to estimate the dependence of potential flooding boundaries on the water discharges. In conjunction with the period of extreme low water that began in 2014 in the basins of lake Baikal and river Angara the problem of estimating the boundaries of shallowing of the lower pool of the IHPS and the Bratsk reservoir is of great current interest. To use the pilot chars we have to vectorize them (Fig. 1)

Models and methods

Results and discussion

Conclusion