Since the damming and channelization of the lower Long Tom River in the 1940s and 1950s, the quality and quantity of habitat for coastal cutthroat trout and spring Chinook salmon in the watershed has dramatically diminished. In order to better understand the potential for stream restoration, this study uses 2D hydraulic modeling to determine the impact of reconnecting historical meander bends to the main stem of the lower Long Tom River on localized flooding, sediment erosion and deposition, and salmonid physical habitat. These models compare the current conditions to two restoration scenarios that allow for fish passage given 1, 2, and 5-year flood events at two study sites. This study reveals important variations in the impact of restoration between the study sites and the reconnection methods. It also suggests that there is the potential for a large increase in the area of accessible habitat with stream restoration.

The master’s thesis deals with the hydraulic analysis of the water flow capacity for the flood flow on the river Litava in the river kilometres 11,550 – 18,315 using the HEC-RAS 5.0.5 specifically 1D-2D numerical model. On the basic of flood areas, depths and speeds the results were evaluated and subsequently was created own proposal flood protection.