Landslides can impact river systems in various ways. When a landslide occurs, it can deposit large amounts of debris into the river, causing blockages and altering the flow of water. This can lead to changes in the river's course and direction, as well as an increase in sediment transport downstream. Additionally, landslides can introduce pollutants and contaminants into the river, affecting water quality and wildlife habitats. Overall, landslides can have significant impacts on the ecology and hydrology of river systems.